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Unlocking the Potential of Indian Pasture Legumes: Nutrition, Mineral, Gas and Methane Production Insights for Use in Semiarid Regions

A peer-reviewed version of this preprint was published in:
Animals 2023, 13(23), 3676. https://doi.org/10.3390/ani13233676

Submitted:

10 October 2023

Posted:

12 October 2023

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Abstract
This study evaluated five annual and eleven perennial Indian pasture legumes species for their nutritive value, dry matter, mineral contents and in vitro fermentation parameters, aiming to boost their potential as animal feed. Legume species significantly differed (p<0.05) in organic matter, crud protein (CP), ether extracts, fibres, and protein fractions. Clitoria ternatea (CT) a perennial had higher (p<0.05) buffer soluble protein (477), while neutral detergent soluble protein was highest in annually grown Lablab purpureus (420 g/kg CP). Atylosia scarabaeoides (AS) had higher NSC (392 g/kg DM) than SC (367 g/kg DM). Rapidly degradable fraction (51.7 g/kg tCHO) was lower (p<0.05) than other fractions of carbohydrate. Total digestible nutrients, digestible energy and metabolisable energy varied and values were higher for Desmenthus virgatus and lowest for Stylosanthas seabrana (SSe). The NE values for lactation (NEL), maintenance (NEM) and gain (NEG) were also higher for DV (6.6, 7.95 and 4.28) and lowest for SSe (3.54, 4.24 and 0.58 kJ/g DM), respectively. dry matter intake, digestible DM (DDM) and relative feed value of legumes differed (p<0.05) with mean values of 2.22% body weight, 592 g/kg DM and 102%, respectively. Annual grasses like Dolichos biflorus, Macroptilium atropurpureum, Rhynchosia minima (RM) were found better with micro minerals compared to other perennials. In vitro dry matter degradability, partition factor, short chain fatty acids and microbial protein production of legumes varied (P<0.05) and mean values were 578 g/kg DM, 5.61 mg DDM/mL, 2.42 mm/g and 352 mg/g, respectively. Gas and CH4 production (mL/g and mL/g DDM) varied (p<0.05) being lowest gas from AS (55.5) and highest from CT-blue (141), while CH4 production was lower (p<0.05) from CT-white and AS (8.24 and 9.14) and higher from Arachis glabrata (AG) and Arachis hagenbackii (AH) (15.2 and 15.1). Methane in total gas was low for DV, RM and CT-w (8.99, 9.72 and 9.51%) and loss of DE and ME as CH4 varied (P<0.05) amongst the legumes with mean values of 4.62 and 7.86%, respectively. Based on these findings, each legume offers unique benefits, allowing for tailored combinations of annual and perennial legumes to optimize rumen feed efficiency.
Keywords: 
animal feed
;  
annual legumes
;  
perennial legumes
;  
nutritional value
;  
minerals
;  
in vitro fermentation
;  
methane production
Subject: 
Biology and Life Sciences  -   Agricultural Science and Agronomy

1. Introduction

Inadequate availability feed and forage coupled with their low nutritive value (crop residues, grasses of pasture and grazing lands) are the prime factors for poor animal production in tropics and subtropics. For ages forage legumes had played an important role in dairy and meat production [1]. Forage legumes species usually had high feeding value as they are generally rich in protein, provides substantial amount of energy, mineral and vitamins with higher intake and digestibility [2,3]. Even in grain-based feed lot livestock production, forage legumes are essential to maintain animal health [4]. In recent many researchers have reviewed the role of forage legumes, for sustenance of mixed crop-livestock production, sustenance of pasture and grazing lands along with ecosystem services [5,6,7]. Dietary supplementation of forage legumes not only increases livestock production primarily through higher intake, nutrient contents, digestibility than cereal crops-grasses, sorghum, maize etc. [8,9] but also improves the rumen fermentation efficiency through enhanced metabolisable energy, protein ratio and ruminal bypass protein availability to animals [10], increased N retention [11] and reduced methane emission [8,12,13]. Further the introduction of forage legumes in grass production areas as grass-legume mixture could be one of the promising strategies to mitigate the GHG emissions from pasture-based livestock production [7].
As per Food and Agriculture Organization of the United Nations (FAO; www.feedipedia.org) lists around 169 legume species are being used as forage and about 20 Mha land area in under forage legume monoculture [14]. Species of Aeschynomene, Arachis, Centrosema, Desmodium, Macroptilium, and Stylosanthes offer promise for improved tropical pasture systems [15]. Alike the wider morphological genetic variability in legume species [16] there exists nutritional variability [17]. In addition to genetic differences the nutritional composition of legumes also influenced by the season and growing location. So, to have correct information on legumes level of supplementation and nutritive value, their evaluation for chemical composition has a substantial impact on the understanding of their nutritional value and also a great influence on animal nutrition [8,18]. The chemical composition (CP, NDF, ADF and lignin) and total digestible nutrients TDN, in vitro digestibility has limited application for formulating precise diet specific to animal species and their physiological stages [19,20]. To have comprehensive information on feeding value of each legume, the present study was planned to evaluate 16 annual and perennial different legume species from nine genera for protein, cell wall constituents, carbohydrate fractions, protein fractions, energy contents, minerals, intake, digestibility and in vitro fermentation pattern (gas and methane production) for their judicious use in ruminant diets.

2. Materials and methods

2.1. Experimental Sites

The study was carried out at Plant Animal relationship Division, ICAR-Indian Grassland and Fodder Research institute, Jhansi (India). Laboratory procedures and animal management for donor sheep were carried out as per Institute animal ethics committee guidelines.

2.2. Sample collection and processing of forage legumes

Annual species: Dolichos biflorus (DB), Lablab purpures (LLP), Macroptilium atropurpureum (MA), Rhynchosia minima (RM), Stylosanthas hamata (SH); Perennial species: Arachis glabrata (AG), Arachis hagenbackii (AH), Atylosia scarabaeoides (AS), Clitoria ternatea-white (CT-W), Clitoria ternatea-blue (CT-B), Centrosoma pubescene (CPb), Desmenthus virgatus (DV), Stylosanthas scabra (SSc), Stylosanthas scofield (SSco), Stylosanthas seabrana (SSe) and Stylosanthus viscosa (SV) were collected randomly from plots (30×10 m) maintained by Grassland and Silvipasture Management Division of Institute. The legumes samples were harvested after monsoon (rainy season) growth in first week of September 2016. Collected samples were dried initially under shade on cemented floor and then in hot air oven at 60°C for 2-3 consecutive days. The DM contents were 36.03, 29.26, 22.21, 17.98, 16.62, 31.14, 28.48, 32.23, 29.13, 35.57, 20.40, 30.38, 39.04, 29.77, 15.83 and 17.71% for AG, AH, CP, DB, CT-w, SSe, SH, SSc, SSco, MA, AS, DV, RM, CT-b and LLP, respectively.

2.3. Chemical analyses

Samples dry matter (DM), crude protein (CP), ether extract (EE) and ash were estimated as per methods of AOAC (1995). CP of samples was estimated as Kjeldahl N × 6.25 by digesting in sulfuric acid and digestion mixture (Consisting of sodium/ potassium sulphate and copper sulphate in 10:1 ratio) using semi auto analyser (Kel Plus Classic-DX, Pelican). The EE was determined by refluxing samples in petroleum ether using extraction apparatus. For ash estimation samples were put in tarred silica basins, desmoked and then basins were put into a muffle furnace at 600°C temperature for 4h. Neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose and lignin (ADL) were estimated by sequential procedure modified by Van Soest et al. [21] using fiber tech (Fibra Plus FES 6, Pelican). Heat labile alpha amylase and sodium sulphite were not used in NDF solution. For lignin (ADL) estimation sample left after ADF estimation were treated with 72% H2SO4 followed by ashing in muffle furnace.

2.4. Carbohydrate and protein fractionation

Carbohydrate fractions were estimated according to the CNCPS [22]. This is broadly classified into 4 fractions as follows:
a)
CA: rapidly degradable CHO including sugars.
b)
CB1: intermediately degradable starch and pectin.
c)
CB2: slowly degradable cell wall.
d)
CC: unavailable/lignin bound cell wall.
Total carbohydrate (tCHO g/kg DM) was determined by subtracting CP, EE and ash contents from 1000. Structural carbohydrates (SC) were calculated as the difference between NDF and neutral detergent insoluble protein and non fiber carbohydrates were estimated as the difference between total CHO and SC [23]. Starch estimated by samples extraction with 80% ethyl alcohol to solubilize free sugars, lipids, pigments and waxes. Residue rich in starch was solubilized with perchloric acid and extract was treated with anthrone-sulphuric acid to determine glucose colorimetrically using standard glucose [24].
Protein fractions of samples were partitioned into five fractions according to Licitra et al. [25]. These are as follows:
PA: non-protein nitrogen (NPN), the difference between total nitrogen and true CP nitrogen precipitated with sodium tungstate (0.30 M) and 0.5 M sulfuric acid.
PB1: buffer soluble protein, the difference between true protein and buffer-insoluble protein, estimated with borate-phosphate buffer (pH 6.7 to 6.8) and freshly prepared 10% sodium azide solution.
PB2: neutral detergent soluble protein (NDSP), buffer-insoluble protein minus ND insoluble protein.
PB3: acid detergent soluble CP, the difference between ND insoluble protein and acid detergent insoluble CP.
PC: indigestible.
All fractions, including CP, were analysed in triplicate and N content determined by Kjeldahl. Crude protein was determined as Kjeldahl N × 6.25 using semi auto analyzer (Kel Plus Classic-DX Pelican India).

2.5. Dry matter intake, digestibility and energy calculations

Legumes dry matter intake (DMI), digestible DM (DDM), relative feed value (RFV), total digestible nutrients (TDN) and net energy for different animal functions i.e. lactation (NEl), gain (NEg) and maintenance (NEm), were calculated using the following equations (DMI = 120/NDF; DDM =88.9-0.779×ADF; RFV =(DDM×DMI)×0.775; TDN = 104.97−(1.302×ADF); NEl =(TDN×0.0245)-0.012; NEg=TDN×0.029)-1.01; NEM = (TDN×0.029)-0.29) of Undersander et al. [26]. Digestible energy (DE, KJ/g DM; DE= TDN×0.04409) and metabolizable energy (ME, KJ/g DM) values were calculated using the equations of Fonnesbeck et al. [27] and Khalil et al. [28], respectively. Metabolizable energy was calculated as 0.821 × DE.

2.6. Estimation of minerals

For minerals estimation legumes samples were wet digested with 3:1 HNO3: perchloric acid mixture, cooled and filtered through Whatman 42 filter paper. The aliquot was used for estimation of calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn) using an atomic absorption spectrophotometer (Varian AA 240) against their standards.

2.7. Donor animals and inoculum preparation

Four male adults of Jalauni sheep with mean body weight of 36.2± 0.217 kg were used as inoculums donors. These animals were maintained on sole berseen hay diet and had free access to clean drinking water. Rumen liquor was collected in a pre-warmed thermos from each animal before feeding using a perforated tube from stomach with the help of vacuum pressure pump. Collected rumen liquor was filtered through four layers of muslin cloth and thus strained rumen liquor obtained from different animals was mixed, kept at 39°C in water bath, gassed with CO2 till used for mixing with incubating buffer media.

2.8. In vitro incubations

In vitro gas production was determined according to the pressure transducer technique of Theodorou et al. [29]. Ruminal fluid was collected in pre warmed thermos using a stomach tube before feeding from adult male Jalauni sheep maintained on berseem hay diet. Collected rumen fluid was filtered through a double layer of cheese cloth and bubbled with CO2. The incubation medium (1L) was prepared by sequential mixing of buffer solution, macro-mineral solution, micro-mineral solution and resazurin solution (Menke and Steingass 1988). Incubation medium was fluxed with CO2 till the pink colour turned colourless and then 250 mL rumen liquor was added to attain incubation medium: rumen liquor ratio of 80:20. Samples (0.5g) of air dry foliages were weighed into three 100 mL serum bottles. Three serum bottles without substrate/sample were used as blanks. Sample and control serum bottles were initially gassed briefly with CO2 before adding 50 mL of inocuolum medium. Bottles were continuously fluxed with CO2 and then sealed with aluminium crimps. Before incubation, the gas pressure transducer was used to adjust head space gas pressure in each bottle to adjust the zero reading on the LED display and then incubated at 39°C for 24 h to estimate the total gas production.

2.9. Methane measurements

Methane in total gas measured at 24h from three bottles incubated for each of the tree leaves was analysed by gas chromatography (Nucon 5765 Microprocessor controlled gas chromatograph, Okhla, New Delhi, India) equipped with a stainless-steel column packed with Porapak-Q and a Flame Ionization Detector. One ml gas sampled using a Hamilton syringe from total gas produced was injected manually (pull and push method of sample injection) into the GC, which was calibrated with standard CH4 and CO2. Methane was also measured from blank bottles incubated for 24h and used for correction of CH4 produced from the inoculum. Methane measured was related to total gas to estimate its concentration [30] and converted to energy and mass values using 39.54 kJ/l CH4 and 0.716 mg/mL CH4 factors, respectively [31]. Short chain fatty acids (SCFA) were calculated using 24h gas production [32], while the partition factor (PF) and microbial mass (MBM) were estimated as described in previously described method [33].

2.10. Statistical analysis

The means of nutritional and gas fermentation parameters of legumes were compared using one way ANOVA of SPPS (version 16) with legumes as fixed factor and parameters as dependent variables. Post hoc multi comparison was performed using Duncan Multiple Range test to differentiate the means at p<0.05 level.

3. Results

3.1. Chemical composition

Legumes differed (p<0.05) in OM, CP, EE, NDF, ADF, cellulose and lignin contents and their mean values were 906, 125, 33.4, 549, 382, 281 and 93.9 g/kg DM, respectively (Table 1). The protein contents were > 150 g/kg DM in CP, CT-b and LLP and lower < 100 g/kg DM in DB, SSe, SH, SSc and SSco (87.9, 80.4, 93.5, 92.2 and 94.8 g/kg DM). The EE contends were higher in CT-w, CT-b and DV (48.3, 46.6 and 63.8 g/kg DM), while lignin contents were lower in LLP (62.7) and AH (68.1) against highest in SSe (134) and CT-w (124 g/kg DM). Stylosanthes species had higher ADF (401 to 508) and cellulose (297 to 365 g/kg DM) contents except (DB) than other evaluated legumes.

3.2. Protein and carbohydrate fractions

Contents of tCHO, SC and NSC varied (p<0.05) in legumes and their mean values were 747, 484 and 263 g/kg DM, respectively. Amongst the evaluated legumes AS is the legume which had higher NSC than SC (392 vs 367 g/kg DM Table 3). SC contents were highest in DB and lowest in AS (684 vs 367 g/kg DM). Carbohydrate fractions CA, CB1, CB2 and CC differed (p<0.05) in legumes and ranged between 143-589, 33.5-84.7, 4.30-551 and 221-428 g/kg tCHO, respectively. Rapidly degradable carbohydrate fraction CB1 (51.7) was lower (p<0.05) than CA (405), CB2 (242) and CC (302 g/kg tCHO), respectively.
Legumes protein fractions PA, PB1, PB2, PB3 and PC differed (p<0.05 Table 2) and had mean values were 226, 295, 209, 167 and 102 g/kg CP, respectively. Legumes had highest (295) accumulation of rapidly degradable protein fraction (PB1) against lowest (1023 g/kg CP) of lignin bound protein fraction (Pc). Clitoria species (CT-w and CT-b) and MA had higher PB1 fraction (437, 477 and 430) and lowest PC fraction (52.9, 71.6 and 75.2 g/kg CP).
Table 2. Carbohydrates (g/kg DM), its fractions (g/kg tCHO) and protein fractions (g/kg CP) of range legumes.
Table 2. Carbohydrates (g/kg DM), its fractions (g/kg tCHO) and protein fractions (g/kg CP) of range legumes.
Legumes Carbohydrate and its fractions Protein fractions
tCHO SC NSC CA CB1 CB2 CC PA PB1 PB2 PB3 PC
AG 730e 424bc 306ghi 470f 71g 127bc 315gh 223de 394fg 161cd 116cd 98.8d
AH 739f 430bcd 309ghi 439ef 57e 282gh 221a 228de 374ef 224e 92.8bc 81.5c
CP 705c 457cde 248def 459ef 48cd 153cd 349def 214cd 185b 305g 202ef 93.7d
DB 781i 683h 976a 143a 52d 551j 253a 324h 123a 300g 118cd 134fg
CT-w 725de 500f 225cd 429ef 37a 121bc 428g 211c 437h 91.5b 208f 52.9a
SSe 823L 561g 261ef 358c 43b 208def 391fg 184b 352e 172d 178e 113e
SH 802k 589g 213bc 278b 61e 365i 297bc 277g 232c 346h 60.8a 83.7c
SSc 780j 483ef 296gh 406de 37a 332hi 224a 236ef 182b 292g 139d 150h
SSco 773i 454cde 319hi 431ef 58e 251efg 260ab 238ef 194b 179d 246g 142gh
SV 797k 464de 333i 414de 65f 277fgh 243a 214cd 265d 138c 254g 129f
MA 689b 415b 274fg 478f 85h 70b 367ef 165a 430h 252f 78.3ab 75.2cd
AS 759h 367a 392i 589g 43b 4.3a 364def 250f 205bc 99.1b 330h 116e
DV 721d 458cde 263ef 410de 49cd 296gh 245a 215cd 281d 310g 110cd 82.9c
RM 749g 516f 233cd 375cd 45bc 254efg 326cde 210c 418gh 25.2a 245g 1015d
CT-b 708c 453cde 254def 450ef 42b 187cde 321cd 205c 477i 33.8a 213f 71.6b
LLP 676a 484ef 191b 356b 33a 388i 223a 215cd 177b 420i 76.8ab 111e
Mean 747 484 263 405 52 242 302 226 295 209 167 102
SEM 0.343 2.74 2.77 14.03 1.96 19.5 9.50 5.30 16.4 16.4 11.3 3.90
Significance <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001
NSC, non-structural carbohydrates; PA, non-protein nitrogen; PB1, buffer soluble protein; PB2, neutral detergent soluble protein; PB3, acid detergent soluble protein; PC, indigestible protein; SEM, standard error of means; SC, structural carbohydrates; tCHO, total carbohydrates.

3.3. Energy, energy efficiency, intake, digestibility and relative feed value of legumes

The TDN, DE and ME contents of legumes varied (p<0.05) and their values were higher for DV (703, 12.9 and 10.6) and lowest for SSe (398, 7.28 and 5.99 kJ/g DM Table 3). Similarly, the NE values of legumes for lactation (NEL), maintenance (NEM) and gain (NEG) were higher for DV (6.66, 7.94 and 4.28) and lowest for SSe (3.53, 4.24 and 0.582 kJ/g DM), respectively. DMI, DDM and RFV of evaluated legumes differed (p<0.05) with mean values of 2.22 % body weight, 592 g/kg DM and 102%, respectively.
Table 3. Energy value of range legumes.
Table 3. Energy value of range legumes.
Legumes TDN DE ME NEL NEM NEG DMI DDM RFV
AG 553de 10.1e 8.32d 5.16f 6.16e 2.45de 2.51g 592de 114.94ef
AH 604f 11.1f 9.11e 5.66g 6.74f 3.08f 2.51g 623f 121.26fg
CP 555e 10.2e 8.36d 5.16ef 6.16e 2.50e 2.19def 593e 100.45cd
DB 511ab 9.36bc 9.69bc 4.70be 5.62bc 1.96bc 1.64a 567bc 72.20a
CT-w 534cde 9.82cde 8.03cd 4.95cdef 5.91cde 2.25cde 2.12cd 581cde 95.48c
SSe 398a 7.28a 5.99a 3.54a 4.24a 0.58a 1.99bc 499a 76.80a
SH 525c 9.65cd 7.90c 4.87cde 5.78c 2.12c 1.93b 575c 86.16b
SSc 498b 9.150b 7.48b 4.58b 5.49b 1.83b 2.20def 559b 95.65c
SSco 528cd 9.69cde 7.94cd 4.87cde 5.82cd 2.16cd 2.27ef 577cd 101.46cd
SV 520ab 9.52bc 7.82bc 4.78f 5.74c 2.08bc 2.20def 572bc 97.68c
MA 552de 10.1de 8.32d 5.12bc 6.12de 2.45de 2.50g 591de 114.36e
AS 605f 11.1f 9.11e 5.66g 6.78f 3.08f 2.73h 623f 131.73h
DV 703g 12.9g 10.6f 6.66h 7.95g 4.28g 2.31f 682g 122.22g
RM 611f 11.2f 9.19e 5.74e 6.82f 3.16f 2.02be 627f 97.92c
CT-b 534cde 9.77cde 8.03cd 4.95b 5.91cde 2.25cde 2.21def 580cde 99.45cd
LLP 613f 11.2f 9.23e 5.74e 6.86 f 3.20f 2.16de 627f 104.94d
Mean 553 10.15 8.40 5.12 6.12 2.47 2.22 592 102.04
SEM 2.04 0.029 0.029 0.021 0.025 0.025 0.011 1.22 0.548
Significance <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001
DM, dry matter; EE, ether extract; Lignin(sa), lignin solubilized with sulphuric acid; fibre expressed inclusive residual ash; NEL, net energy for lactation; NEM, net energy for maintenance; NEG, net energy for growth; NSC, non-structural carbohydrates; OM, organic matter; SEM, standard error of means; TDN, total digestible nutrients.

3.4. Minerals

Micro minerals (Cu, Zn, Fe and Mn) of legumes varied (p<0.05) in range of 11.11-76.74, 20.77-65.85, 31.53-1288.04 and 18.61-70.51 ppm, respectively (Table 4). Ca and Mg varied from 0.55-2.77 and 0.25-0.88% with mean values of 1.26 and 0.42%, respectively.

3.5. Fermentation pattern

Fermentation parameters (DMD, ME, PF, SCFA and MBP) of the legumes incubated in sheep inoculums varied (p<0.05 Table 5) and their mean values were 578 g/kg DM, 5.88 kJ/g DM, 5.61mL/mg DM, 2.42 mm/g and 351.65 mg/g, respectively. Microbial protein production efficiency varied (p<0.05) from 0.32 for DV to 0.68 for CT-w.

3.6. Gas, methane and loss of energy as methane

In vitro gas and methane production (mL/g and mL/g DDM) of legumes varied (p<0.05 Table 6). Gas production (mL/g) was lowest from AS (55.5) and highest from CT-b (141), while CH4 production was lower (p<0.05) from CT-w and AS (8.24 and 9.14) and higher from AG and AH (15.2 and 15.1). Methane in total gas varied (p<0.05) and was low for DV, RM and CT-w (8.99, 9.72 and 9.51%) and higher for MA, AG and AH (14.1, 14.0 and 13.9%), respectively. The loss of DE and ME as CH4 varied (p<0.05) amongst the legumes with mean values of 4.62 and 7.86%, respectively.

4. Discussion

4.1. Chemical composition

Information on the chemical composition of forages has significant impact on the understanding of their nutritive value and animal production [8,18]. Legumes evaluated in present study except DB and Stylosanthes species had CP contents above 110 g/kg DM recommended to fulfil the protein requirement of growing cattle. Crude protein and NDF contents of Arachis, Centro, Stylo and Siratro legumes in range of 129-191 and 452-592 g/kg DM [34] were within range of our values baring Stylosanthes species and AS. The earlier reported CP contents of C. pubescens (221) and S. guyyanensis (179 g/kg DM) reported were higher than our values (172 and 80.4-105 g/kg DM), respectively [17]. The CP, EE, NDF, AFD, cellulose and lignin contents of C. pubesecens were found similar to earlier reports [17,35]. Whereas S. gyuyanensis was in lower contents than Stylosanthes except lignin. Further the EE contents of C. pubescens and S. guyanensis (24.0 and 47.0 g/kg DM) of these workers were similar to values of CPb (25.0) and SSc (43.2 g/kg DM), respectively. The OM, NDF and ADF contents in C. pubescens, S. hamata, and S. scabra was recorded as same by Musco et al. [36]. However, the lignin contents of C. pubescens (167) and S. scabra (187) were higher than our values (103 and 72.9 g/kg DM), respectively. The NDF and ADF contents of C. pubescens, Macroptelium bracteatum and M. gracile was at par with previous study [37]. Similarly, the range of CP, EE, OM, NDF, ADF, cellulose and lignin contents in Macroptilium species, Rhynchosia minima, S. humilis, Clitoria ternatea were found in coherence with other studies [38,39]. In contrast, significant differences in DM contents (154-253 g/kg DM) of 13 legumes were also recorded previously [40]. The CP content in 24 accessions of Arachis species was ranged from 14.7 to 22.55 [41] that was like our results whereas in a study it was recorded even at higher range (184-250 g/kg DM) [42]. Whereases OM and lignin contents (873-919) and 63-82 g/kg DM) were like values presented in present study. The CP (73-129), EE (15-36) and ADF (373-424) except NDF (416-510 g/kg DM) of ten Stylosanthes guyanensis varieties recorded by Li et al. [43] were within the range of our observed values of Stylosantehs species. Furthermore, the value chemical composition recorded in Arachis hypogeal, C. pubescens, Clitoria ternatea, M. atropurpureus and S. guyanensis were found similar of earlier studies [44,45].

4.2. Protein and carbohydrate fractions

Feeds protein fractions composition reflect rumen degradation rates that estimate the dietary nitrogen efficiency. Thus, the utilization level of the nitrogenous fraction is important at the evaluation of feeds and at the specification of nutritional requirements of ruminants [46]. Protein fractions (PB1, PB2, PB3 and PC) differed (p<0.05) across legumes may be attributed to differences in concentrations of CP and lignin. About 50‒150 g/kg CP of total forage N is bound to lignin, or rather, is unavailable to ruminal microorganisms [47] and our legumes values for PC lies within this range (52.9 to 150 g/kg CP). The PC fraction of Arachis pinto ten accessions in range of 178-276 g/kg CP [42] (Ferreira et al. 2012) was higher than our Arachis species values. Due to good source of protein the annual Lablab purpures is predominantly cultivated in dry and semi-dry tropical regions [48].
Carbohydrates constitute the main energy source of plants (500-800 g/kg DM) and play an important role in animal nutrition as a prime source of energy for rumen microorganisms [47]. Carbohydrate accumulation in fodder crops is influenced by several factors like plant species, variety, growth stage and environmental conditions during growth (Buxton and Fales 1994). Mlay et al. [49] reported mean tCHO content of 746 g/kg DM for Macropttlium atropurpurus legume which was higher than our values (689 g/kg DM). The higher tCHO contents for blue (800) and white (830 g/kg DM) varieties of Clitoria ternatea than our CT-w (725) and CT-b (708 g/kg DM) values was reported earlier [38]. The tCHO (626-701 g/kg DM) for ten Arachis pinto accessions found marginally lower than our AG and AH values [42]. Higher SC in DB, SSe, SH and RM may be due to their higher NDF contents recorded in the present study. The legumes AG, AH, CPb, MA, CT-b and AS had higher contents of CA fraction (> 44 g/kg tCHO) and feeds higher in this fraction are considered good energy sources to stimulate rumen microorganism growth [50] and the synchronism between the protein and carbohydrate digestion rates, having an important effect on the end products of fermentation and on animal production [51]. Low contents of unavailable carbohydrate fraction (CC) in AH, DB, SSe, DV, SV and LLP may be due to their lower lignin contents. This indigestible fraction with CB2 usually affects animal intake by the rumen fill, which can reduce animal performance [52]. In our study we recorded that DB, DV, RM, SH and LLP legumes with higher hemicelluloses contents (315, 253, 258, 221 and 220 g/kg DM) had higher CB2 fraction contents (551, 296, 254, 365 and 388 g/kg tCHO) which is more slowly degraded in the rumen, impacting microbial synthesis and animal performance [53]. Higher hemicellulose concentrations result in higher concentrations of CB2 fraction. Carvalho et al. [50] reported that NDF concentration influences carbohydrate fraction CB2 and forages high in NDF concentration usually have higher values of CB2. Our results partially agree with these observations that most of the legumes with higher NDF contents had higher CB2 fraction value. Additionally, annual forage RM rich in flavonoids and found suitable for long-term rangelands improvement [54,55].

4.3. Energy, energy efficiency, intake, digestibility and relative feed value of legumes

Feed or fodder nutritive value is a function of its dry matter intake and its ability to provide the nutrients in the right proportion required by animals for different physiological functions [56]. Greater calculated DMI value for AG, AH, MA and DV (2.51, 2.51, 2.50 and 2.73%) than other legumes (1.64-2.31%) may be due to lower NDF contents. The NDF of forages has been negatively correlated with DMI which is always not consistent, although the NDF is positively related with resistance to comminution [57]. Lowest and highest DMD of SSe and DV legumes may be due to their highest (501) and lowest (266 g/kg DM) ADF contents, respectively.
Musco et al. [36] reported higher NEL values for C. pubescens, S. hamata and S. scabra (9.53, 6.16 and 5.49 kJ/g DM) than our recorded values (5.16, 4.88 and 4.58 kJ/g DM), respectively. Similarly, ME values of C. pubescens were higher (6.53) than our values (5.78 kJ/g DM) [58]. The ME contents (9.44-10.36 kJ/g DM) of 13 legumes were higher than ME values observed in present study [40]. The TDN consists of digestible nutrients that are available for livestock and is primarily related to forage ADF contents. With increase in ADF there is decline in TDN resulting unavailability of forage nutrients to animals [59]. The relatively higher values for TDN (634 g/kg DM), GE (17.2), DE (11.5) and ME (9.44 kJ/g DM) were recorded than values of MA in present study [49].
The IVDMD of C. pubescens and S. guyanensis (530 and 570 g/kg DM) reported earlier was like our values of CPb (513) and SSe and SV (578 and 580 g/kg DM) but lower to SH (641, SSc (631) and SSco (646 g/kg DM), respectively [17]. The OMD of C. pubescens (478), S. hamata (609) and S. scabra (593) were relatively higher than our values (457, 447 and 471 g/kg DM), respectively. Tona et al. [35] reported higher ME and OMD for C. pubescens than our values. The DMD and OMD (614-712 and 586-688 g/kg DM) for five forage legumes [37] were more than range values (395-663 and 375-526 g/kg DM) of legumes evaluated in present study. Similarly, the mean OMD and DMD (656 and 684 g/kg DM) were higher than average OMD and DMD values of tested legumes. The higher values for OMD (642-739 g/kg DM) in legume forage than our values are mentioned earlier[40]. Fernandes et al. [60] recorded DMD of ten Arachis species over three years in range of 501-632 g/kg DM. The values of IVOMD between 600 to 740 g/kg DM for 24 accessions of Arachis pinto substantiate our DMD values of Arachis species [41]. Highest and lowest TDN values for DV and SSe in present study may be attributed to differences in their digestibility and lower and higher ADF contents as ADF increased TDN values decreases.
The NDF and ADF contents are negatively associated with OMD and ME values of legumes [40]. Intake an important part of forages nutritive value is partially related to cell wall content and bulkiness of forages. Lowest value of DMI for DB (1.64) versus highest of AS (2.73%) may be attributed to their maximum (730) and minimum NDF contents (440 g/kg DM) as the NDF contents are negatively associated with DMI [47].
The relative feed value (RFV) of ten varieties of S. guyanensis in range of 102.8-130.5% [43] were higher than values determined for Stylosanthes species (70.80-101.46%). The values of IVDMD and TDN of A. hypogeaea (78.86 and 71.44), C. pubescens (59.89 and 51.30), Clitoria ternatea (74.15 and 60.20) M. atropurpureus (66.51 and 56.15) and S. guyanensis (66.22% and 54.43%) which were higher than our values for these legumes [45]. The DMD of Arachis species (AG and AH) was higher (650 and 663 g/kg DM) except LLP than other legume species is similar to previous observations [61] where reported that DMD of Arachis species in general is greater than other tropical legumes.

4.4. Minerals

The Ca contents (0.50-0.80%) of legumes studied here were found relatively lower than earlier reported [17], while Mg contents (0.32-0.63%) were like our values of legumes. Similar trend of Ca and Mg contents were reported in other study [62]. Legumes Fe, Cu, Mn and Zn contents in range of 441-494, 2.42-7.14, 55.2-61.3 and 34.8-65.3 ppm [62] were more or less similar to our micro mineral values. In contrast, the relatively lower Ca (1.01-1.62%) and higher Mg (0.92-1.96%) of different Arachis pinto cultivars under humid and sub-humid environment were reported than our values [63]. Further the Cu, Fe, Zn and Mn reported for this legume were inconsistent to our values. Macro (Ca and Mg) and micro minerals (Cu. Zn, Fe and Mn) of white and blue varieties of Clitoria ternatea reported earlier [38] were more or less similar to our CT-w and CT-b values. Fernandes et al. [60] reported Ca and Mg values in range of 1.4-2.47% and 0.08-0.59% for ten Arachis species over three years were similar to our Arachis species values. Macro (Ca and Mg) and micro minerals (Cu, Fe, Zn and Mn) of four herbaceous legumes and two browse legumes reported by [63] were in partial agreement to our mineral values. The variation in mineral contents of legume species may be due to differences in soil mineral contents, growth stage, fertilizer application and environment conditions [64,65].

4.5. Fermentation pattern

The 1.15 µmole SCFA content for C. pubescens legume at 24h of fermentation was reported earlier [35]. The partition factor in range of 3.07-4.94 mg/mL reported earlier [36] was lower than PF values (3.45-7.08) of legumes evaluated in present study. The reason for higher PF values for evaluated legumes may be ascribed to less gas production due to lower DMD.
Partition factor an indicator of fermentation efficiency of a feedstuff is expressed as volume of gas (mL) produced per mg of substrate degraded. Legumes mean PF values were higher (5.61) than the theoretically possible maximum value (4.14) [33]. Higher PF values for CT-w (7.05) could not translate to higher microbial mass probably due to their less gas production. Higher SCFA for DV, LLP, SSc and RM may be due to their higher gas production as reported. For DV legume microbial protein production was lowest (143 mg/g) and methane production was highest (26.45 mL/g DDM) which is consistent with previous observations [66]. Greater PF values for CT-w did not translate to greater microbial mass as noted in previous study [67]. We expected with higher PF to translate to greater microbial mass as PF is the measure of efficiency of microbial production. We can only speculate the reason for this observation, but higher SCFA value noted for DV consistent with previous report that microbial mass and SCFA are inversely related [68]. It may be that DV partitioned more energy into SCFA versus microbial mass production, while in case of LLP energy partition was well distributed between SCFA and microbial mass production.

4.6. Gas, methane production and loss of energy as methane

One of the options to improve the feed efficiency through efficient rumen fermentation is that dry matter conversion to methane is less and utilization by animal is more. Methane an end-product of rumen fermentation causes 2-12% loss of dietary energy [69]. This loss of feed energy as methane varies with its quality [70,71,72,73] and animal species. Methane % of gas between 15.9 to 18.4%) from 13 legumes [40] was higher than our recorded values for 16 legumes (9.0 to 14.1%). Our values for proportion of methane in total gas except for DV, RM and CT-b were within the value (12.3-15.9%) reported earlier [62]. Lopez et al. [74] categorised methane reduction potential as low potential (% of CH4 in gas between 11 and 14%). So, legumes evaluated in present study had low methane production potential. Furthermore, gas production was higher from AG and AH (110.25 and 108.92) than MA and CPb (90.46 and 99.14 ml/g) as recorded in present study [34]. A higher gas production for S. hamata and S. scabra (195 and 193) than C. pubescens (136 mL/g OM) were reported and these values were higher with similar gas production pattern [36]. Similarly, a report on higher gas production at 24h for C. pubescens (25.4 mL/200mg) than our values was published [58]. Like our observations [40] recorded significant difference in gas production (42.56 to 51.42 mL/200mg) from hays of 13 legumes and these values were higher than our values (55.46 to 141.26 mL/g) from 16 legumes and these differences may be due to our lower OMD values as low OM fermented for gas production. Further the methane production in range of 7.36-8.78 mL/200mg was higher than our methane production values. The differences in gas and methane production of evaluated pasture legume species may be ascribed to the variation in their chemical composition and degradation. Such variation in methane and gas production of legume species has been recorded earlier [40,75,76,77].
The proportion of methane to total gas production is an important indicator of methane emission potential of feed/fodder degradation. This ratio of methane to gas for common feeds (hays, concentrate, mixture of hays and concentrate) vary between 16-20%. Methane production from Desmodium intortum (3.67), Medicago sativa (5.90) and Vicia sativa (5.73 mL/200mg DM) legumes observed by [62] was also higher than most of our legumes but similar to Arachis species. Maccarana et al. [78] reported gas production, methane production and CH4% of total gas in range of 72-480 mL/g DM, 7.3-77.5 mL/g and 9.4-40.61% from 390 observations of 30 studies. Relatively lower values of gas production, methane production and CH4% total gas in present study may be due to sheep rumen liquor as values of gas and methane production and CH4% total gas were higher when bovine rumen liquor was used for incubations [79,80]. Greater methane production may be attributed to their higher IVDMD values. In line of present findings, previous studies reported that feedstuffs with higher gas production and IVDMD tended to have higher methane production per gram DM incubated [81]. Methane emission differences within legumes may be attributed to the variability in their chemical constituents as reported earlier [82,83,84]. The differences in relative proportion of CH4 to energy values (CH4% of DE and % of ME) may be attributed to variations in legumes energy values, level of methane production, dry matter degradability. Variability in proportion of methane to energy of feeds and fodders has been reported earlier [62,84].

5. Conclusions

Range legumes evaluated in present study had CP more than 100 g/kg DM except for Stylosanthes species. Legumes AG, AH, DV and AS had higher energy values and relative feed values along with lower accumulation of structural carbohydrates. The CH4% of total gas and CH4 (% of DE and ME) were lowest for DV and RM legumes.

Author Contributions

Conceptualization, S.S., T.S., P.K. and Y.R.; methodology, S.S., T.S., P.K., M.C. and U.Y.A.; formal analysis, S.S., T.S. and P.K.; investigation, S.S., T.S. and B.K.B.; writing—original draft preparation, S.S., T.S., P.K., M.C. and Y.R; writing—review and editing, S.S, T.S, P.K., U.Y.A., M.C. and Y.R.; visualization, P.K. and U.Y.A.; supervision, S.S., B.K.B. and Y.R.; project administration, S.S. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Not applicable.

Acknowledgments

Authors are thankful to Director IGFRI for providing financial support and Head Plant Animal Relationship Division for providing laboratory and animal facilities to carry this research work.
Conflicts of interest: The authors have no conflicts of interest.

References

  1. Russelle, M.P. Alfalfa: After an 8,000-year journey, the" Queen of Forages" stands poised to enjoy renewed popularity. Am. Sci. 2001, 89, 252–261. [Google Scholar] [CrossRef]
  2. Olalekan, A.J.; Bosede, B.F. Comparative study on chemical composition and functional properties of three Nigerian legumes (jack beans, pigeon pea and cowpea). Journal of Emerging Trends in Engineering and Applied Sciences 2010, 1, 89–95. [Google Scholar]
  3. Amiri, F. Comparison of nutritive values of grasses and legume species using forage quality index. Songklanakarin Journal of Science & Technology 2012, 34. [Google Scholar]
  4. Wattiaux, M.; Howard, T. , Technical dairy guide: nutrition and feeding. University of Wisconsin. 2001.
  5. Muir, J.P.; Pitman, W.D.; Dubeux Jr, J.C.; Foster, J.L. The future of warm-season, tropical and subtropical forage legumes in sustainable pastures and rangelands. Afr J Range Forage Sci 2014, 31, 187–198. [Google Scholar] [CrossRef]
  6. Schultze-Kraft, R.; Rao, I.M.; Peters, M.; Clements, R.J.; Bai, C.; Liu, G. Tropical forage legumes for environmental benefits: An overview. Tropical Grasslands-Forrajes Tropicales 2018, 6, 1–14. [Google Scholar] [CrossRef]
  7. Soussana, J.-F.; Lemaire, G. Coupling carbon and nitrogen cycles for environmentally sustainable intensification of grasslands and crop-livestock systems. Agric., Ecosyst. Environ. 2014, 190, 9–17. [Google Scholar] [CrossRef]
  8. Dewhurst, R.J.; Delaby, L.; Moloney, A.; Boland, T.; Lewis, E. Nutritive value of forage legumes used for grazing and silage. Irish Journal of Agricultural and Food Research 2009, 167–187. [Google Scholar]
  9. Kleen, J.; Taube, F.; Gierus, M. Agronomic performance and nutritive value of forage legumes in binary mixtures with perennial ryegrass under different defoliation systems. The Journal of Agricultural Science 2011, 149, 73–84. [Google Scholar] [CrossRef]
  10. Virgona, J.; Harris, C.; Kemp, S.; Evans, J.; Salmon, R. Australian Legume Research–synthesis and future directions. Crop and Pasture Science 2012, 63, 918–926. [Google Scholar] [CrossRef]
  11. Foster, J.; Adesogan, A.; Carter, J.; Blount, A.; Myer, R.; Phatak, S. Intake, digestibility, and nitrogen retention by sheep supplemented with warm-season legume hays or soybean meal. J. Anim. Sci. 2009, 87, 2891–2898. [Google Scholar] [CrossRef]
  12. Eckard, R.; Grainger, C.; De Klein, C. Options for the abatement of methane and nitrous oxide from ruminant production: A review. Livestock science 2010, 130, 47–56. [Google Scholar] [CrossRef]
  13. Puchala, R.; Min, B.; Goetsch, A.; Sahlu, T. The effect of a condensed tannin-containing forage on methane emission by goats. J. Anim. Sci. 2005, 83, 182–186. [Google Scholar] [CrossRef]
  14. Graham, P.H.; Vance, C.P. Legumes: importance and constraints to greater use. Plant Physiol. 2003, 131, 872–877. [Google Scholar] [CrossRef]
  15. Thomas, D.; Sumberg, J. A review of the evaluation and use of tropical forage legumes in sub-Saharan Africa. Agric., Ecosyst. Environ. 1995, 54, 151–163. [Google Scholar] [CrossRef]
  16. Lewis, G.; Schrire, B.; Mackinder, B.; Lock, M. Legumes of the World. Royal Botanic Gardens, Kew. Edinb. J. Bot 2005, 62, 195–196. [Google Scholar]
  17. Valarini, M.; Possenti, R. Research note: Nutritive value of a range of tropical forage legumes. Tropical Grasslands 2006, 40, 183. [Google Scholar]
  18. Zhao, D.; MacKown, C.T.; Starks, P.J.; Kindiger, B.K. Interspecies variation of forage nutritive value and nonstructural carbohydrates in perennial cool-season grasses. Agron. J. 2008, 100, 837–844. [Google Scholar] [CrossRef]
  19. Guo, X.; Wilmshurst, J.F.; Li, Z. Comparison of laboratory and field remote sensing methods to measure forage quality. Int. J. Environ. Res. Public Health 2010, 7, 3513–3530. [Google Scholar] [CrossRef]
  20. Kassi, A.L.; Newbold, C.; Wallace, R. Chemical composition and degradation characteristics of foliage of some African multipurpose trees. Anim. Feed Sci. Technol. 2000, 86, 27–37. [Google Scholar]
  21. Van Soest, P.V.; Robertson, J.B.; Lewis, B.A. Methods for dietary fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci. 1991, 74, 3583–3597. [Google Scholar] [CrossRef]
  22. Sniffen, C.J.; O'Connor, J.D.; Van Soest, P.J.; Fox, D.G.; Russell, J.B. A net carbohydrate and protein system for evaluating cattle diets: II. Carbohydrate and protein availability. J. Anim. Sci. 1992, 70, 3562–3577. [Google Scholar] [CrossRef]
  23. Caballero, R.; Alzueta, C.; Ortiz, L.T.; Rodríguez, M.L.; Barro, C.; Rebolé, A. , Carbohydrate and protein fractions of fresh and dried common vetch at three maturity stages. Agron. J. 2001, 93, 1006–1013. [Google Scholar] [CrossRef]
  24. Sastry, V.; Kamra, D.; Pathak, N. Laboratory manual of animal nutrition. Indian Veterinary Research Institute, Izatnagar, India 1999, 255. [Google Scholar]
  25. Licitra, G.; Hernandez, T.M.; Van Soest, P.J. Standardization of procedures for nitrogen fractionation of ruminant feeds. Anim. Feed Sci. Technol. 1996, 57, 347–358. [Google Scholar] [CrossRef]
  26. Undersander, D. , Mertens, D., Thiex, N. Forage Analyses. In Information Systems Division, National Agricultural Library (United States of America) NAL/USDA, 10301 Baltimore Avenue Beltsville, Md. 2070., 1993.
  27. Fonnesbeck, P.V.; Clark, D.H.; Garret, W.N.; Speth, C.F. Predicting energy utilization from alfalfa hay from the Western Region. Proc. Am. Anim. Sci.(Western Section) 1984, 35, 305–308. [Google Scholar]
  28. Khalil, J.; Sawaya, W.N.; Hyder, S.Z. Nutrient composition of Atriplex leaves grown in Saudi Arabia. Rangeland Ecology & Management/Journal of Range Management Archives 1986, 39, 104–107. [Google Scholar]
  29. Theodorou, M.K.; Williams, B.A.; Dhanoa, M.S.; McAllan, A.B.; France, J. A simple gas production method using a pressure transducer to determine the fermentation kinetics of ruminant feeds. Anim. Feed Sci. Technol. 1994, 48, 185–197. [Google Scholar] [CrossRef]
  30. Tavendale, M.H.; Meagher, L.P.; Pacheco, D.; Walker, N.; Attwood, G.T.; Sivakumaran, S. Methane production from in vitro rumen incubations with Lotus pedunculatus and Medicago sativa, and effects of extractable condensed tannin fractions on methanogenesis. Anim. Feed Sci. Technol. 2005, 123, 403–419. [Google Scholar] [CrossRef]
  31. Santoso, B.; Mwenya, B.; Sar, C.; Takahashi, J. Methane production and energy partition in sheep fed timothy silage-or hay-based diets. Jurnal Ilmu Ternak dan Veteriner 2007, 12, 27–33. [Google Scholar]
  32. Getachew, G.; Makkar, H.; Becker, K. Tropical browses: contents of phenolic compounds, in vitro gas production and stoichiometric relationship between short chain fatty acid and in vitro gas production. The Journal of Agricultural Science 2002, 139, 341–352. [Google Scholar] [CrossRef]
  33. Blümmel, M.; Steingaβ, H.; Becker, K. The relationship between in vitro gas production, in vitro microbial biomass yield and 15N incorporation and its implications for the prediction of voluntary feed intake of roughages. Br. J. Nutr. 1997, 77, 911–921. [Google Scholar] [CrossRef]
  34. Herrero, M.; Jessop, N. In In vitro gas production of tropical pasture legumes. In Proceedings of the XVIII international grassland congress, Winnipeg, Manitoba and Saskatoon, Saskatchewan, Canada, 1997; pp. 63–64. [Google Scholar]
  35. Tona, G.; Ogunleke, F.; Asaolu, A.; Yusuf, A.; Olasusi, E. In vitro evaluation of grass and legume/browse species grazed by west african dwarf goats in South-Western Nigeria. IOSRJ. Agric. Vet. Sci 2017, 10, 70–75. [Google Scholar] [CrossRef]
  36. Musco, N.; Koura, I.B.; Tudisco, R.; Awadjihè, G.; Adjolohoun, S.; Cutrignelli, M.I.; Mollica, M.P.; Houinato, M.; Infascelli, F.; Calabrò, S. , Nutritional characteristics of forage grown in south of Benin. Asian-Australas J Anim Sci 2016, 29, 51. [Google Scholar] [CrossRef]
  37. Mokoboki, H.; Ndlovu, L.; Ayisi, K. Chemical and physical parameters of forage legume species introduced in the Capricorn region of Limpopo Province, South Africa. S. Afr. J. Anim. Sci. 2002, 32, 247–255. [Google Scholar]
  38. Deshmukh, S.; Jadhav, V. Bromatological and mineral assessment of Clitoria ternatea Linn. leaves. Energy (KJ) 2014, 459, 489.24-2.83. [Google Scholar]
  39. Silva, D.L.; Oliveira, K.P.; Aroeira, L.J.; Chaves, D.F.; Ponciano, M.F.; Braga, A.P.; Júnior, D.M.L. Chemical composition of Caatinga potential forages species. Tropical and Subtropical Agroecosystems 2015, 18, 267–272. [Google Scholar] [CrossRef]
  40. Suha Uslu, O.; Kurt, O.; Kaya, E.; Kamalak, A. Effect of species on chemical composition, metabolizable energy, organic matter digestibility and methane production of some legume plants grown in Turkey. J Appl Anim Res 2018, 46, 1158–1161. [Google Scholar] [CrossRef]
  41. Carvalho, M.; Quesenberry, K. Agronomic evaluation of Arachis pintoi (Krap. and Greg.) germplasm in Florida. Arch. Zootec. 2012, 61, 19–29. [Google Scholar] [CrossRef]
  42. Ferreira, A.L.; Maurício, R.M.; Fernandes, F.D.; Carvalho, M.A.; Ramos, A.K.B.; Junior, R.G. Ranking contrasting genotypes of forage peanut based on nutritive value and fermentation kinetics. Anim. Feed Sci. Technol. 2012, 175, 16–23. [Google Scholar] [CrossRef]
  43. Li, M.; Zi, X.; Zhou, H.; Hou, G.; Cai, Y. Chemical composition and in vitro digestibility of Stylosanthes guianensis varieties. Grassl Sci 2014, 60, 125–129. [Google Scholar] [CrossRef]
  44. Ali, A.; Abdullah, L.; Karti, P.D.; Chozin, M.; Astuti, D. Production, competition indices, and nutritive values of Setaria splendida, Centrosema pubescens, and Clitoria ternatea in mixed cropping systems in peatland. Media Peternakan 2013, 36, 209–209. [Google Scholar] [CrossRef]
  45. Nasrullah, M.N.; Niimi, M.; Akashi, R.; Kawamura, O. Nutritive evaluation of forage plants grown in South Sulawesi, Indonesia II. Mineral Composition. Asian-Australasian Journal of Animal Science 2004, 17, 63–67. [Google Scholar] [CrossRef]
  46. da Silva Cabral, L.; Filho, S.d.C.V.; Muniz, P.A.; Malafaia, R. d. P. L.; da Silva, J.F.C.; Vieira, R.A.M.; Pereira, E.S. Frações protéicas de alimentos tropicais e suas taxas de digestão estimadas pela incubação com proteases ruminais. Rev Bras Zootec 2000, 29, 2316–2324. [Google Scholar]
  47. Van Soest, P. Nutritional Ecology of The ruminants, Cornell University, Ithaca, 1994. 1994.
  48. Naeem, M.; Shabbir, A.; Aftab, T.; Khan, M.M.A. Lablab bean (Lablab purpureus L.)—An untapped resilient protein reservoir. Neglected and Underutilized Crops 2023, 391–411. [Google Scholar]
  49. Mlay, P.S.; Pereka, A.; Chikula Phiri, E.; Balthazary, S.; Igusti, J.; Hvelplund, T.; Riis Weisbjerg, M.; Madsen, J. Feed value of selected tropical grasses, legumes and concentrates. Vet Arh 2006, 76, 53–63. [Google Scholar]
  50. Carvalho, G.G.P. d.; Garcia, R.; Pires, A.J.V.; Pereira, O.G.; Fernandes, F.É. P.; Obeid, J.A.; Carvalho, B.M.A. d. , Carbohydrate fractioning of elephantgrass silage wilted or enriched with cocoa meal. Rev Bras Zootec 2007, 36, 1000–1005. [Google Scholar] [CrossRef]
  51. Nocek, J.E. In situ and other methods to estimate ruminal protein and energy digestibility: a review. J. Dairy Sci. 1988, 71, 2051–2069. [Google Scholar] [CrossRef]
  52. Mertens, D. Predicting intake and digestibility using mathematical models of ruminal function. J. Anim. Sci. 1987, 64, 1548–1558. [Google Scholar] [CrossRef]
  53. Ribeiro, K.G.; Pereira, O.G.; Valadares Filho S d, C.; Garcia, R.; Cabral, L.d.S. Characterization of the protein and the carbohydrate fractions, and the respective degradation rates of Tifton 85 bermudagrass hay at different regrowth ages. Rev Bras Zootec 2001, 30, 589–595. [Google Scholar] [CrossRef]
  54. Adewole, A.H.; Famuyide, I.M.; McGaw, L.J.; Selepe, M.A.; October, N. Antifungal Compounds from the Leaves of Rhynchosia minima. Chem. Biodivers. 2022, 19, e202200837. [Google Scholar] [CrossRef]
  55. Osman, I.M.; Acar, R.; Babikir, E.S.N. EXPLOITING INDIGENOUS PLANTS SPECIES TO REHABILITATE DEGRADED RANGELANDS OF SUDAN USING RHYNCHOSIA MINIMA (L.) DC. PROCEEDING BOOK 2022, 157. [Google Scholar]
  56. Teferedegne, B. New perspectives on the use of tropical plants to improve ruminant nutrition. Proc. Nutr. Soc. 2000, 59, 209–214. [Google Scholar] [CrossRef] [PubMed]
  57. Romney, D.; Gill, M. Intake of forages. Forage Evaluation in Ruminant Nutrition, CAB International 2000, 43–62. [Google Scholar]
  58. Warly, L.; Fariani, A.; Ichinohe, T.; Fujihara, T. Study on nutritive value of tropical forages in North Sumatra, Indonesia. Asian-Australas J Anim Sci 2004, 17, 1518–1523. [Google Scholar]
  59. Aydın, N.; Mut, Z.; Mut, H.; Ayan, İ. Effect of autumn and spring sowing dates on hay yield and quality of oat (Avena sativa L.) genotypes. 2010.
  60. Fernandes, F.D.; Ramos, A.K.; Carvalho, M.A.; Maciel, G.A.; ASSIS, G.M.D.; Braga, G.J. Forage yield and nutritive value of Arachis spp. genotypes in the Brazilian savanna. Tropical Grasslands-Forrajes Tropicales 2017, 5, 19–28. [Google Scholar] [CrossRef]
  61. Gama, T. d. C. M.; Volpe, E.; Lempp, B. Biomass accumulation and chemical composition of Massai grass intercropped with forage legumes on an integrated crop-livestock-forest system. Rev Bras Zootec 2014, 43, 279–288. [Google Scholar] [CrossRef]
  62. Melesse, A.; Steingass, H.; Schollenberger, M.; Rodehutscord, M. Screening of common tropical grass and legume forages in Ethiopia for their nutrient composition and methane production profile in vitro. Tropical Grasslands-Forrajes Tropicales 2017, 5, 163–175. [Google Scholar] [CrossRef]
  63. Sébastien, A.; Jérôme, B.; Claude, A.; Soumanou, T.S.; Marcel, H.; Brice, S. Variety and environmental effects on crude protein concentration and mineral composition of Arachis pintoi (Kaprovickas & Gregory) in Benin (West Africa). Journal of Applied Biology and Biotechnology 2013, 1, 024–028. [Google Scholar]
  64. Juknevičius, S.; Sabienė, N. The content of mineral elements in some grasses and legumes. Ekologija 2007, 53, 44–52. [Google Scholar]
  65. McDowell, L.; Valle, G. Major minerals in forages. Forage evaluation in ruminant nutrition. 2000, 373–397. [Google Scholar]
  66. McCrabb, G.; Berger, K.; Magner, T.; May, C.; Hunter, R. Inhibiting methane production in Brahman cattle by dietary supplementation with a novel compound and the effects on growth. Aust. J. Agric. Res. 1997, 48, 323–329. [Google Scholar] [CrossRef]
  67. Anele, U.; Südekum, K.-H.; Hummel, J.; Arigbede, O.; Oni, A.; Olanite, J.; Böttger, C.; Ojo, V.; Jolaosho, A. Chemical characterization, in vitro dry matter and ruminal crude protein degradability and microbial protein synthesis of some cowpea (Vigna unguiculata L. Walp) haulm varieties. Anim. Feed Sci. Technol. 2011, 163, 161–169. [Google Scholar] [CrossRef]
  68. Hungate, R. The rumen and its microbes Academic Press New York and London; Academic Press: New York, Estados Unidos, 1966. [Google Scholar]
  69. Johnson, K.A.; Johnson, D.E. Methane emissions from cattle. J. Anim. Sci. 1995, 73, 2483–2492. [Google Scholar] [CrossRef]
  70. Mirzaei-Aghsaghali, A.; Maheri-Sis, N. Factors affecting mitigation of methane emission from ruminants I: feeding strategies. Asian J. Anim. Vet. Adv. 2011, 6, 888–908. [Google Scholar] [CrossRef]
  71. Singh, S.; Koli, P.; Bhadoria, B.K.; Agarwal, M.; Lata, S.; Ren, Y.; Du, X. Proanthocyanidins Modulate Rumen Enzyme Activities and protein utilization in vitro. Molecules 2022, 27, 5870. [Google Scholar] [CrossRef] [PubMed]
  72. Singh, S.; Kundu, S.S. Effect of tropical browse leaves supplementation on rumen enzymes of sheep and goats fed Dichanthium annulatum grass-based diets. Trop. Anim. Health Prod. 2010, 42, 1181–1187. [Google Scholar] [CrossRef]
  73. Koli, P.; Singh, S.; Bhadoria, B.K.; Agarwal, M.; Lata, S.; Ren, Y. Sequential Extraction of Proanthocyanidin Fractions from Ficus Species and Their Effects on Rumen Enzyme Activities In Vitro. Molecules 2022, 27, 5153. [Google Scholar] [CrossRef]
  74. Lopez, V.M.; Florentino, B.; Barlaz, M.A. Chemical composition and methane potential of commercial food wastes. Waste Manage. 2016, 56, 477–490. [Google Scholar] [CrossRef]
  75. Banik, B.; Durmic, Z.; Erskine, W.; Ghamkhar, K.; Revell, C. In vitro ruminal fermentation characteristics and methane production differ in selected key pasture species in Australia. Crop and Pasture Science 2013, 64, 935–942. [Google Scholar] [CrossRef]
  76. Bezabih, M.; Pellikaan, W.; Tolera, A.; Khan, N.; Hendriks, W. Chemical composition and in vitro total gas and methane production of forage species from the M id R ift V alley grasslands of E thiopia. Grass Forage Sci. 2014, 69, 635–643. [Google Scholar] [CrossRef]
  77. Boga, M.; Yurtseven, S.; Kilic, U.; Aydemir, S.; Polat, T. Determination of nutrient contents and in vitro gas production values of some legume forages grown in the Harran plain saline soils. Asian-Australas J Anim Sci 2014, 27, 825. [Google Scholar] [CrossRef] [PubMed]
  78. Maccarana, L.; Cattani, M.; Tagliapietra, F.; Bailoni, L.; Schiavon, S. Influence of main dietary chemical constituents on the in vitro gas and methane production in diets for dairy cows. Journal of Animal Science and Biotechnology 2016, 7, 1–8. [Google Scholar] [CrossRef] [PubMed]
  79. Bueno, I.C.; Brandi, R.A.; Franzolin, R.; Benetel, G.; Fagundes, G.M.; Abdalla, A.L.; Louvandini, H.; Muir, J.P. In vitro methane production and tolerance to condensed tannins in five ruminant species. Anim. Feed Sci. Technol. 2015, 205, 1–9. [Google Scholar] [CrossRef]
  80. Cone, J.W.; Van Gelder, A.H.; Bachmann, H. Influence of inoculum source on gas production profiles. Anim. Feed Sci. Technol. 2002, 99, 221–231. [Google Scholar] [CrossRef]
  81. Jayanegara, A.; Togtokhbayar, N.; Makkar, H.P.S.; Becker, K. Tannins determined by various methods as predictors of methane production reduction potential of plants by an in vitro rumen fermentation system. Anim. Feed Sci. Technol. 2009, 150, 230–237. [Google Scholar] [CrossRef]
  82. Singh, S.; Bhadoria, B.K.; Koli, P.; Lata, S. , Seasonal variation in chemical and biochemical constituents of tropical top feed species: components in silvipasture system. Range Manag. Agrofor. 2021, 42, 312–319. [Google Scholar]
  83. Singh, S.; Bhadoria, B.K.; Koli, P.; Singh, A. Nutritional evaluation of top foliages for livestock feeding in semi arid region of India. Indian J. Anim. Sci. 2019, 89, 1389–1398. [Google Scholar] [CrossRef]
  84. Singh, S.; Kushwaha, B.; Nag, S.; Mishra, A.; Singh, A.; Anele, U. In vitro ruminal fermentation, protein and carbohydrate fractionation, methane production and prediction of twelve commonly used Indian green forages. Anim. Feed Sci. Technol. 2012, 178, 2–11. [Google Scholar] [CrossRef]
Table 1. Chemical composition of range legumes (g/kg DM).
Table 1. Chemical composition of range legumes (g/kg DM).
Legumes OM CP EE NDF ADF Cellulose Lignin Hemi cellulose
AG 873b 123f 20.2ab 479b 381cd 2725e 101ef 976a
AH 878c 116e 23.4abc 478b 342b 273e 68.1ab 136bcd
CP 905g 172i 27.5cd 549cde 380c 266c 103ef 169d
DB 897f 88b 28.1cd 730h 414ef 325e 82.4bcd 316g
CT-w 919i 146h 48.3f 566f 396cde 270c 124gh 171d
SSe 930L 80a 26.6cd 604g 501g 365g 134i 103ab
SH 923j 93c 27.0cd 624g 403e 297d 99.2e 221e
SSc 915h 92c 43.2ef 548cde 423f 345f 72.9abc 124abc
SSco 886d 95c 18.5a 529cd 401de 307de 83.8bc 129abc
SV 927k 105d 24.6bcd 545cde 407ef 320g 80.7bc 139bcd
MA 855a 141g 24.9bcd 482b 382cd 271e 105ef 99.0a
AS 894e 105d 29.7d 439a 342b 213b 115fg 98.2a
DV 928kl 143gh 63.8g 519c 266a 177a 73.5abc 253ef
RM 934m 143gh 41.5e 595fg 337b 229b 1027ef 258f
CT-b 937n 183j 46.6f 544cde 396cde 296d 94.6de 147cd
LLP 896e 180j 40.3e 556de 335b 267c 62.7a 220e
Mean 906 12.54 33.4 549 382 28.09 93.9 168
SEM 2.12 0.283 0.421 - 1.51 6.93 1.69 2.87
Significance <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001
AG, Arachis glabrata; AH, Arachis hagenbackii; AS, Atylosia scarabaeoides; CPb, Centrosoma pubescene; CT-b; Clitoria ternatea(blue) CT-w, Clitoria ternatea(white); DV, Desmenths virgatus; DB, Dolichos biflorus; LLP, Lablab purpures; MA, Macroptilium atropurpureum; RM, Rhynchosia minima; SSe, Stylosanthas seabrana; SH, Stylosanthas hamata, SSc, Stylosanthas scabra, SSco, Stylosanthas scofield; SV, Stylosanthus viscosa.ADF, acid detergent fibre expressed inclusive residual ash; CP, crude protein; EE, ether extract; Lignin(sa), lignin solubilized with sulphuric acid; NDF, neutral detergent fibre expressed inclusive residual ash; OM, organic matter; SEM, standard error of means.
Table 4. Macro (%) and micro minerals (ppm) of range legumes.
Table 4. Macro (%) and micro minerals (ppm) of range legumes.
Legumes Cu Zn Fe Mn Ca Mg
AG 76.7h 65.8g 1150cde 47.5c 2.77f 0.59j
AH 60.7g 61.1g 737bc 47.3c 2.74f 0.58j
CP 28.7ef 42.2e 246ab 31.9ab 1.48e 0.37e
DB 35.7f 31.9bc 1271de 70.5ef 1.37e 0.41g
CT-w 24.9cde 41.7de 311ab 40.8bc 0.60a 0.37f
SSe 14.9ab 35.0 215ab 20.3a 0.94c 0.24e
SH 11.1a 26.7ab 259ab 77.37f 0.80b 0.25ab
SSc 13.6ab 32.0bc 174a 22.1a 1.34e 0.28bc
SSco 16.1abc 48.7f 1023cd 54.5cd 1.47e 0.29cd
SV 12.4ab 20.8a 137a 27.2a 1.44e 0.46h
MA 21.1bcde 30.1bc 1573e 61.4e 1.17d 0.34ef
AS 18.5abcd 28.5bc 1288de 72.3f 0.93c 0.36ef
DV 27.3def 27.1ab 32.8a 28.3ab 0.93c 0.88k
RM 59. 6g 25.5ab 183a 18.6a 0.58a 0.32de
CT-b 72.0h 35.3cd 31.5a 41.9bc 0.55a 0.53i
LLP 62.8g 39.3de 39.4a 41.6bc 0.98c 0.44gh
Mean 34.8 37.0 542 44.0 1.26 0.42
SEM 0.726 0.544 41.41 1.08 0.11 0.003
Significance <.0001 <.0001 <.0001 <.0001 <.0001 <.0001
SEM, standard error of means.
Table 5. Partition factor (PF), short chain fatty acids (SCFA), degradable dry matter and microbial protein production from fermentation of range legumes in sheep inoculum.
Table 5. Partition factor (PF), short chain fatty acids (SCFA), degradable dry matter and microbial protein production from fermentation of range legumes in sheep inoculum.
Legumes ME kJ/g DMD PF SCFA mm/g MBM mg/g EMBP mg/g
AG 6.07cd 649fg 6.09cde 2.44 cd 421efg 0.63 cd
AH 6.04cd 663g 6.35cde 2.41 cd 445g 0.64 cd
CP 5.77bcd 513b 5.35bc 2.20bcd 306 bc 0.60 bcd
DB 6.11cd 577cd 5.26bc 2.54 cd 346 cde 0.56bcd
CT-w 4.86ab 559cd 7.05de 1.80ab 392defg 0.68d
SSe 5.61bc 578cd 5.49bc 2.41 cd 355 cdef 0.59 bcd
SH 5.82bcd 641fg 6.20cde 2.37cd 417 defg 0.63 cd
SSc 6.18cd 631efg 5.60bcde 2.61de 385defg 0.59 bcd
SSco 5.78bcd 646 fg 6.25cde 2.42 cd 424 efg 0.63cd
SV 5.84bcd 580 cd 5.24bc 2.54 cd 342 cd 0.57 bcd
MA 5.59bc 594cde 7.08e 2.00abc 407 defg 0.66 d
AS 4.49a 394a 5.53bc 1.64a 238b 0.58 bcd
DV 6.53cd 409a 3.45a 2.77de 142a 0.32a
RM 6.25cd 547bc 4.82abc 2.60 cde 302 bc 0.53bc
CT-b 6.43cd 602de 4.37ab 3.13e 301 bc 0.48b
LLP 6.73d 660g 5.56bcd 2.76de 402 defg 0.58 bcd
Mean 5.88 578 5.61 2.42 352 0.58
SEM 0.080 10.4 0.151 0.059 11.00 0.013
Significance 0.001 <.0001 <.0001 <.0001 <.0001 <.0001
DMD, dry matter degradability; ME, metabolisable energy; MBM, microbial protein production; EMBP, efficient of microbial protein production; PF, partition factor (gas mL/mg DM); SFCA, short chain fatty acids; SEM, standard error of means.
Table 6. Gas production, methane production and loss of energy as methane from in vitro fermentation of range legumes in sheep inoculum.
Table 6. Gas production, methane production and loss of energy as methane from in vitro fermentation of range legumes in sheep inoculum.
Legumes Gas mL/g CH4 mL/g Gas mL/g DDM CH4 mL/g DDM CH4% Gas CH4%DE CH4% ME
AG 110cde 15.2d 170ab 23.5b 13.9 bc 5.77ef 7.03 ef
AH 109cde 15.1d 164 ab 22.7 b 13.9 bc 5.23 cdef 6.37 cdef
CP 99.1bcd 11.0bc 192 abc 21.4 b 11.1 abc 4.14 abc 5.04 abc
DB 114de 13.0cd 199 abc 22.6 b 11.5 abc 5.31 def 6.47def
CT-w 81.3b 8.24a 145 a 14.7 a 10.1 ab 3.23 a 3.94a
SSe 108cde 11.5bc 188 abc 20.1 ab 10.8 abc 6.10f 7.43 f
SH 107cde 11.5bc 166 ab 18.1ab 11.2 abc 4.61 bcd 5.61 bcd
SSc 117de 12.8cd 186 abc 20.4 b 11.3 abc 5.37 def 6.54 def
SSco 109cde 11.9bc 169 ab 18.6ab 11.4 abc 4.75 bcde 5.79 bcde
SV 115de 11.4bc 197 abc 19.7 ab 10.0 a 4.60 bcd 5.60 bcd
MA 90.4bc 12.4cd 153 a 21.0b 14.1 c 4.72 bcde 5.75 bcde
AS 55.4a 9.1ab 188 abc 23.2b 12.5 abc 3.17 a 3.86a
DV 122def 10.8 bc 309d 26.4 c 8.99a 3.24 a 3.94a
RM 117de 11.4 bc 215bc 21.0b 9.72 a 3.92 ab 4.78 ab
CT-b 141f 13.4cd 235 c 22.3 b 9.51a 5.27 cdef 6.42 cdef
LLP 124ef 12.8 cd 190 abc 19.4 ab 10.4abc 4.49 bcd 5.46 bcd
Mean 107 12.0 192 21.0 11.3 4.62 5.63
SEM 1.80 0.219 5.86 0.495 0.315 0.134 0.163
Significance <.0001 <.0001 <.0001 0.010 0.041 <.0001 <.0001
DDM, dry matter; ME, metabolisable energy; SEM, standard error of means.
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