Submitted:
02 October 2025
Posted:
04 October 2025
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Abstract
Moderately fermentable dietary fiber, especially when combined with stimbiotic (STB) supplementation, can enhance intestinal health, nutrient utilization, and overall perfor-mance in laying hens, although effects depend on fiber type, level, and diet composition. To investigate this, 1,200 Bovans White laying hens (32 weeks old) were assigned to a 2 × 6 factorial experiment with two levels of supplementation (without or with 0.01% STB) and six dietary fiber treatments: Control (corn–soybean), Wheat–High CF, 75:25 wheat–corn, 50:50 wheat–corn, 25:75 wheat–corn, and Corn–soybean–Low CF. The study spanned five 28-day periods, evaluating productive performance, egg quality, and intestinal morphol-ogy. Dietary fiber levels significantly improved feed intake, egg production, egg mass, feed conversion, and intestinal structure, while STB alone had limited effects. Hens fed 75:25 and 50:50 wheat–corn diets consumed more feed, and the highest egg production and mass were observed in birds receiving Control, 75:25 wheat–corn, and Wheat–High CF diets. Egg quality benefited from the fiber–STB interaction, producing heavier eggs with higher yolk pigmentation, thicker shells, and greater Haugh unit and specific gravity. STB supplementation increased jejunal villus width and absorptive area, whereas fiber type affected ileal morphology. In conclusion, high dietary fiber improves performance, egg quality, and intestinal health in laying hens, and supplementation with 0.01% STB further enhances these effects.
Keywords:
fermentable fiber
; feed efficiency
; gut health
; xylanase
; wheat bran
1. Introduction
Historically, dietary fiber has been considered a low-value component in poultry nutrition, viewed as an energy diluent and associated with the presence of antinutritional factors [1]. However, recent studies show that its effect is highly dependent on solubility and fermentability, which can positively or negatively impact performance and gut health [2,3]. Moderately fermentable fiber can stimulate gastrointestinal tract development, enhance endogenous enzyme production, and modulate the microbiota, resulting in improved nutrient utilization and immune responses [4,5,6].
In laying hens, this issue is even more relevant due to their prolonged production cycle, increasing animal welfare demands, and the frequent use of fibrous ingredients in commercial diets [7]. Nevertheless, the presence of soluble non-starch polysaccharides (NSPs), especially arabinoxylans, can increase digesta viscosity, impair digestion and microbiota balance, and predispose birds to enteric disorders [8,9,10].
Commercial diets are most commonly based on corn, which contain low levels of arabinoxylans and fiber, limiting the effectiveness of xylanase in enhancing fiber fermentation. Conversely, the inclusion of wheat bran tends to increase the availability of substrates for enzyme activity. Wheat bran is an insoluble fiber source rich in arabinoxylans—estimated at around 23.2% [11]. Studies have shown that moderate inclusion of wheat bran can improve intestinal health in poultry, as it provides energy for enterocytes through the fermentation of arabinoxylo-oligosaccharides by the microbiota, producing short-chain fatty acids (SCFAs) [12,13]. According to Suriano et al. (2018), wheat bran also exerts anti-inflammatory effects and improves intestinal barrier function and microbial composition.
The use of exogenous enzymes, such as xylanase, has emerged as a strategy to hydrolyze NSPs and release fermentable oligosaccharides, thereby improving digestibility and reducing the negative effects of viscosity [14,15]. In this context, stimbiotic (STB) supplementation—a combination of β−1,4-endo-xylanase and xylo-oligosaccharides (XOS)—is noteworthy, as it has a dual mode of action: degrading fibrous fractions and providing prebiotic substrates for cecal fermentation, resulting in SCFA production with beneficial effects on gut health [16,17,25].
Although studies in broilers have consistently shown positive effects of STB, results in laying hens remain limited and inconsistent, varying according to fiber type and level, diet composition, and production conditions [2,3,6]. Thus, a knowledge gap remains regarding which dietary fiber levels, with or without STB supplementation, can simultaneously optimize performance, egg quality, and intestinal integrity in commercial layers.
Therefore, this study evaluated the effect of different dietary high-fiber levels, with or without STB supplementation, on productive performance, egg quality, and intestinal morphology of laying hens.
2. Materials and Methods
2.1. Local and Animals
This study was conducted at Campus II of the Federal University of Paraíba, located in the city of Areia, at a latitude of 6°57′48″ S, a longitude of 35°41′30″ W, and an altitude of 618 m in Paraíba, Brazil. All protocols and procedures followed animal welfare guidelines and were approved by the local Ethics Committee of the Federal University of Paraíba (Areia, Paraíba, Brazil).
A total of 1,200 Bovans White laying hens, 32 weeks of age, were used in the study. These birds were obtained at one day of age and managed according to the instructions described in the strain manual until the beginning of the experimental phase. The hens were housed in conventional laying facilities with clay-tiled roofs, equipped with trough feeders and nipple drinkers. They were kept in galvanized wire cages measuring 100 × 45 × 45 cm.
2.2. Experimental Diets and Design
The diets were formulated to meet the nutritional requirements of the Bovans White strain, considering an average intake of 120 g/bird/day, according to [19]. The experimental design was conducted in a 2 × 6 factorial arrangement, with two levels of supplementation (without or with 0.01% stimbiotic - STB) and six fiber levels, consisting of: 1. Control (corn–soybean); 2. Wheat–High CF; 3. 75:25 wheat–corn; 4. 50:50 wheat–corn; 5. 25:75 wheat–corn; 6. Corn–soybean–Low CF; 7. Control (corn–soybean) + STB; 8. Wheat–High CF + STB; 9. 75:25 wheat–corn + STB; 10. 50:50 wheat–corn + STB; 11. 25:75 wheat–corn + STB; 12. Corn–soybean–Low CF + STB (Table 1). The STB (Signis, β-1,4-endo-xylanase and xylo-oligosaccharides, AB Vista, Marlborough, UK) was supplemented at 100 mg/kg of feed, providing an activity of 16,000 BXU/kg. One BXU (xylanase unit) corresponds to the amount of enzyme required to release 1 nmol of reducing sugars from birchwood xylan per second at 50 °C and pH 5.3.
2.3. Experimental Variables
Performance
The experiment consisted of five periods of 28 days each. The variables evaluated included feed intake (FI, g/bird/day). To determine FI, the residual feed was weighed and subtracted from the amount of feed initially provided for the entire period. At the end of each 28-day period, the amount of feed consumed was divided by the number of hens in each treatment and by the number of days to calculate the average grams of feed consumed per hen per day.
Egg production (EP, %) was determined by recording the number of eggs produced per day, including broken, cracked, and abnormal eggs (e.g., soft-shelled eggs). This value represented the average EP of the hens during each period.
Egg mass (EM, g) was calculated by multiplying the average egg weight by the total number of eggs produced during the experimental period.
Feed conversion ratio per egg mass (FCR-EM, g/g) was calculated as the total FI divided by the total EM produced (kg/kg). Feed conversion ratio per dozen eggs (FCR-DZ, g/dozen) was calculated as the total FI (kg) divided by the number of dozens of eggs produced.
Body weight variation (BWV, g) was obtained by weighing the hens at the beginning and at the end of the experimental phase. The average BWV is expressed in grams per hen.
Egg Quality
Egg quality analyses were performed during the last three days of each 28-day period. Three eggs with average weight from each replicate were collected, individually identified, and weighed on an analytical balance. Subsequently, the eggs were broken onto a flat surface to measure albumen height (mm) using a depth micrometer (model S-8400, Ames®) [20].
Yolk and albumen weights were then recorded. The shells were dried in a forced-air oven at 45 °C for 48 h and subsequently weighed. Percentages of each component were calculated by dividing the weight of the component by the total egg weight and multiplying by 100.
Yolk color was assessed using the DSM Yolk Color Fan scale (DSM, São Paulo, Brazil).
The Haugh Unit was determined using the equation proposed by [21]: HU = 100 × log (H – 1.7 × W^0.37 + 7.57), where HU = Haugh Unit, H = albumen height (mm), and W = egg weight (g).
Eggshell thickness was assessed with a digital micrometer at three evenly spaced locations on the equatorial region of the shell, and the arithmetic mean was used as the representative value.
Specific gravity was determined using the saline flotation method. Eggs were immersed in sodium chloride (NaCl) solutions with densities ranging from 1.0700 to 1.0975 g/cm3, with a gradient of 0.0025 between successive solutions. The density of the solutions was regularly verified using an oil densimeter.
Intestinal Morphology
At the end of the experiment, one bird per replicate was euthanized for the subsequent collection of biological material. A 1 cm fragment was collected from the middle portion of the duodenum, jejunum, and ileum of each bird, with each treatment comprising; these fragments were fixed by immersion in 10% formaldehyde. The tissue fragments were embedded in paraffin according to standard histological procedures. Next, 5 µm sections were cut from each paraffin block in a microtome, and the histological slides were stained with “periodic acid–Schiff” (PAS) and scanned with a Motic camera (Motic Instruments Inc., Xiamen, China) coupled to an Olympus BX-53 microscope (Olympus Corporation, Tokyo, Japan) with Motic Image Plus 2.0 image analyzer software (Motic Instruments Inc., Xiamen, China).
For each photomicrograph, three measurements of the intestinal villus and crypt depth were taken, totaling 90 measurements (10 animals × 3 photomicrographs × 3 measurements) for each variable mentioned above per treatment. The villus width and height (μm) was measured from the region of the intestinal mucosa that coincided with the upper portion of the crypts until its apex. The crypt depth (μm) was the distance between the villus base to the crypt–villus transition region. The villus–crypt ratio was determined by the ratio of the villus height to the crypt depth. The absorptive surface area (μm) was estimated by considering a villus as a cylindrical structure. Villus absorptive surface area was calculated using the formula: Villus absorptive surface area = 2π × (average villus width/2) × villus height [23].
2.4. Statistical Analysis
Data were analyzed as a 2 × 6 factorial using the PROC GLM procedure of SAS (version 9.4, SAS Institute Inc., Cary, NC, USA). The factors included stimbiotic supplementation (0 or 100g/ton of feed) and levels of dietary fiber (Control (corn–soybean); 2. Wheat–High CF; 3. 75:25 wheat–corn; 4. 50:50 wheat–corn; 5. 25:75 wheat–corn; 6. Corn–soybean–Low CF). Significance was set at p ≤ 0.05 and tendency was declared at 0.05 < p ≤ 0.1. Significantly different means were separated using Tukey’s HSD.
3. Results
3.1. Performance
There was no significant interaction between dietary fiber levels and STB supplementation (p > 0.05). Independently, STB supplementation did not affect feed intake (FI), egg production (EP), egg mass (EM), feed conversion per egg mass (FCR-EM) or per dozen eggs (FCR-DZ), or body weight variation (BWV) (p > 0.05). However, dietary fiber levels significantly influenced all variables evaluated (p < 0.05; Table 2).
Hens fed the 50:50 wheat–corn and 75:25 wheat–corn diets had higher FI compared with the other treatments (p = 0.0029). The highest EP and EM were obtained from hens fed the Control (corn–soybean), 75:25 wheat–corn, and Wheat–High CF diets (p < 0.0001). Consequently, these diets also promoted better FCR-EM (p < 0.0001) and FCR-DZ (p < 0.0001). Regarding BWV, hens fed the Corn–soybean–Low CF, 25:75 wheat–corn, and 75:25 wheat–corn diets exhibited less body weight loss at the end of the experimental period (p = 0.0152).
3.2. Egg Quality
Interactions between STB supplementation and dietary fiber levels were observed for yolk color, shell thickness, and eggshell specific gravity (p < 0.0001) (Table 3 and Table 4). The main effect of STB supplementation significantly affected Haugh unit (p = 0.0222) and specific gravity (p < 0.0001).
Laying hens fed the Control (corn–soybean), 25:75 wheat–corn, and 75:25 wheat–corn diets produced heavier eggs (p < 0.0001). More intensely pigmented yolks were obtained from hens fed the Control (corn–soybean) and Wheat–High CF diets (p < 0.0001). The highest Haugh unit and specific gravity values were observed in eggs from hens fed the Wheat–High CF diet (p < 0.0001), whereas thicker eggshells were produced by hens fed the 75:25 wheat–corn diet (p = 0.0198). Dietary fiber levels did not influence the percentage of yolk, albumen, or eggshell.
Table 4 details the interactions between dietary fiber levels and STB supplementation. Eggs from hens fed the 25:75 wheat–corn diet supplemented with STB exhibited darker yolk pigmentation, similar to those from hens receiving the 50:50 wheat–corn diet without STB. The Control (corn–soybean) diet supplemented with STB resulted in thicker eggshells (p < 0.0001). Moreover, STB supplementation in the Corn–soybean–Low CF, 50:50 wheat–corn, or 25:75 wheat–corn diets significantly increased specific gravity (p < 0.0001).
3.3. Intestinal Morphology
Interactions between STB supplementation and dietary fiber levels were observed for duodenum and ileum morphology in laying hens (p < 0.0001) (Table 5 and Table 6). The main effect of STB supplementation promoted wider villi (p < 0.0001) and a greater absorptive area in the jejunum (p = 0.0063). In the ileum, hens not receiving STB supplementation exhibited taller villi (p = 0.0092) and deeper crypts (p = 0.0054). The Control (corn–soybean), Corn–soybean–Low CF, and Wheat–High CF diets also influenced ileal morphology, promoting wider villi (p = 0.0025) and a greater absorptive area.
Table 6 shows the specific interactions between dietary fiber levels and STB supplementation. In the duodenum, hens fed the Corn–soybean–Low CF diet with STB exhibited wider villi (p = 0.0106). Conversely, the 25:75 wheat–corn diet with STB reduced villus width, while the 50:50 wheat–corn diet without STB resulted in shallower crypts (p = 0.0011). Additionally, the Corn–soybean–Low CF diet with STB decreased the villus-to-crypt ratio (p = 0.0058), whereas the Wheat–High CF diet with STB increased the absorptive area (p = 0.0086). In the ileum, hens receiving the 50:50 wheat–corn diet with STB presented narrower villi (p = 0.0011), a lower villus-to-crypt ratio (p = 0.0058), and a reduced absorptive area (p = 0.0086).
Table 6.
Influence of dietary fiber levels and STB supplementation on the intestinal morphology in laying hens.
Table 6.
Influence of dietary fiber levels and STB supplementation on the intestinal morphology in laying hens.
| Diets | Duodenum | Jejunum | Ileum | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Villus width (μm) | Villus height (μm) | Crypt depth (μm) | Villus-to-crypt ratio | Absorptive area | Villus width (μm) | Villus height (μm) | Crypt depth (μm) | Villus-to-crypt ratio | Absorptive area | Villus width (μm) | Villus height (μm) | Crypt depth (μm) | Villus-to-crypt ratio | Absorptive area | ||
| Means for main effect of STB | ||||||||||||||||
| STB | + | 227.99 | 1475.87 | 130.99 | 11.40* | 335961.40 | 174.40a | 1241.06* | 123.31 | 10.26* | 219140.03a* | 120.28 | 689.01b | 82.14b | 8.48* | 85329.04 |
| - | 222.07 | 1472.02 | 128.90 | 11.53* | 327658.78 | 147.96b* | 1170.26* | 118.79 | 9.91* | 175594.70b* | 122.95 | 755.23a | 91.03a | 8.47* | 94820.98 | |
| Means for main effect of Fiber levels | ||||||||||||||||
| Fiber levels | Control (corn– soybean) | 236.88 | 1450.11 | 124.57 | 11.72 | 343478.44 | 156.36 | 1113.23 | 116.55 | 9.58 | 172678.47 | 125.84a | 759.63 | 90.45 | 8.56 | 96595.74a |
| Corn–soybean – Low CF | 236.31 | 1440.79 | 129.25 | 11.20 | 335886.31 | 163.44 | 1251.48 | 125.37 | 10.04 | 211014.41 | 130.93a | 749.15 | 89.15 | 8.56 | 100142.94a | |
| 50:50 wheat–corn | 224.90 | 1409.99 | 130.40 | 10.93 | 319300.48 | 157.94 | 1176.85 | 125.20 | 9.56 | 186341.53 | 119.16ab | 714.31 | 88.38 | 8.22 | 91060.62ab | |
| 25:75 wheat–corn | 220.41 | 1546.29 | 134.65 | 11.62 | 342153.02 | 168.73 | 1211.42 | 120.14 | 10.14 | 209486.93 | 107.2b | 688.81 | 82.48 | 8.40 | 75438.83b | |
| 75:25 wheat–corn | 213.25 | 1444.77 | 129.15 | 11.31 | 308635.09 | 156.31 | 1230.10 | 119.06 | 10.47 | 194397.30 | 118.54ab | 746.35 | 87.05 | 8.57 | 84733.48ab | |
| Wheat – High CF | 223.16 | 1447.56 | 130.88 | 11.21 | 324053.74 | 146.12 | 1114.93 | 115.88 | 9.67 | 163737.46 | 126.10a | 679.90 | 86.67 | 7.95 | 92480.37ab | |
| Pooled SEM | 0.052 | 0.053 | 0.037 | 0.035 | 0.073 | 0.086 | 0.080 | 0.053 | 0.042 | 0.133 | 0.066 | 0.070 | 0.061 | 0.038 | 0.114 | |
| p-Value | STB | 0.2749 | 0.5182 | 0.9377 | 0.4139 | 0.6161 | 0.0001 | 0.6331 | 0.7308 | 0.4119 | 0.0063 | 0.5508 | 0.0092 | 0.0054 | 0.464 | 0.0641 |
| Fiber levels | 0.0924 | 0.2949 | 0.1923 | 0.2771 | 0.2774 | 0.5587 | 0.3727 | 0.2715 | 0.0592 | 0.2404 | 0.0025 | 0.1829 | 0.5037 | 0.2029 | 0.0156 | |
| STB* Fiber levels | 0.0106 | 0.2262 | 0.0011 | 0.0058 | 0.0086 | 0.0742 | 0.848 | 0.1193 | 0.6487 | 0.1753 | 0.0011 | 0.2348 | 0.0058 | 0.1507 | 0.0086 | |
STB, stimbiotic; CF, crude fiber; *, interaction effect; a,b Means in a column, within a group, with different superscripts are significantly different (p < 0.05).
Table 7.
Interactions between dietary fiber levels and STB supplementation on the intestinal morphology in laying hens.
Table 7.
Interactions between dietary fiber levels and STB supplementation on the intestinal morphology in laying hens.
| Diets | Duodenum | Ileum | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Villus width (μm) |
Crypt depth (μm) |
Villus-to-crypt ratio |
Absorptive area |
Villus width (μm) |
Crypt depth (μm) | Absorptive area | |||||||||
| STB | + | - | + | - | + | - | + | - | + | - | + | - | + | - | |
| Control (corn– soybean) |
235.64Aab | 238.11Aa | 120.22Aa | 128.92Aab | 11.70Aa | 11.73Aa | 331621.91Aab | 355334.96Aa | 133.52Aa | 118.16Aa | 92.57Aa | 88.33Aa | 101858.81Aa | 91332.68Aa | |
| Fiber levels | Corn–soybean – Low CF |
258.01Aa | 214.62Aa | 133.83Ab | 124.66Ab | 10.53Bb | 11.88Aa | 355183.26Aa | 316589.35Aab | 124.20Aa | 137.66Aa | 84.05Aab | 94.25Aa | 91952.60Aa | 108333.28Aa |
| 50:50 wheat–corn | 223.50Aab | 222.81Aa | 137.66Ab | 124.09Bb | 11.22Aab | 11.21Aab | 339579.57Aab | 308527.91Ab | 94.00Bb | 120.52Aa | 73.64Bb | 99.71Aa | 57953.41Bb | 92924.27Aa | |
| 25:75 wheat–corn | 208.04Ab | 218.46Aa | 128.11Aab | 130.19Aab | 11.20Aab | 11.41Aab | 296733.41Ab | 320536.78Aab | 121.55Aa | 116.78Aa | 84.69Aab | 89.41Aa | 93264.89Aa | 88856.35Aa | |
| 75:25 wheat–corn | 211.68Aab | 229.15Aa | 131.06Ab | 138.25Aa | 11.60Aa | 11.64Aa | 320082.39Aab | 364223.65Aa | 116.62Aa | 120.47Aa | 79.79Aab | 85.18Aa | 80661.37Aab | 88805.61Aa | |
| Wheat – High CF | 239.72Aab | 210.08Aa | 128.36Aab | 132.44Aab | 11.32Aab | 10.54Ab | 346183.93Aab | 292417.03Bb | 134.53Aa | 117.68Aa | 88.21Aab | 88.56Aa | 95276.01Aa | 89684.73Aa | |
| Pooled SEM | 0.052 | 0.066 | 0.061 | 0.114 | 0.066 | 0.061 | 0.114 | ||||||||
| p-Value | STB*Fiber levels | 0.0106 | 0.0011 | 0.0058 | 0.0086 | 0.0011 | 0.0058 | 0.0086 | |||||||
AB, uppercase letters compare the inclusion or not of STB within columns; abc, lowercase letters compare dietary fiber levels within rows; significantly different (p < 0.05) according to Tukey’s test.
4. Discussion
This study evaluated the effect of different dietary high-fiber levels, with or without STB supplementation, on productive performance, egg quality, and intestinal morphology of laying hens. It was demonstrated that dietary fiber levels, rather than STB supplementation alone, were the main drivers of productive performance in laying hens. Hens fed diets with moderate wheat inclusion 75:25 wheat–corn or wheat–high CF presented higher EP and EM, which translated into improved FCR. These findings align with reports that moderately fermentable fiber stimulates gastrointestinal tract development and supports nutrient utilization through the production of short-chain fatty acids [5,18]. In contrast, excessive inclusion of wheat (50:50 wheat–corn) increased FI without improving egg output, suggesting that higher fiber levels may have diluted dietary energy, leading to compensatory FI but lower efficiency. Similar outcomes were observed by [2], who noted that high-fiber diets can impair nutrient digestibility in layers.
With respect to BWV, hens fed the 25:75 wheat–corn and 75:25 wheat–corn diets exhibited reduced weight loss. This effect may reflect a balance between adequate fermentable substrates and the metabolic benefits of short-chain fatty acid production, which provide energy to enterocytes and support gut health [12,24].
Regarding egg quality, both dietary fiber levels and their interaction with STB supplementation influenced yolk pigmentation, Haugh unit, shell thickness, and specific gravity. Heavier eggs and darker yolks were associated with corn–soybean and wheat–high CF diets, in agreement with [7], who reported that yolk pigmentation is directly linked to dietary pigment sources and gut absorptive capacity. The beneficial effect of STB on eggshell traits, particularly the increase in specific gravity when combined with low- or moderate-fiber diets, may result from enhanced mineral absorption following partial hydrolysis of arabinoxylans [14,16]. However, the inconsistent effects observed across fiber levels suggest that the efficacy of STB in laying hens is highly diet-dependent, confirming the variability reported in previous studies [3,6].
Intestinal morphology was also markedly influenced by fiber level and its interaction with STB supplementation. Wider villi and larger absorptive areas were observed in hens receiving the corn–soybean or wheat–high CF diets, indicating that these formulations supported epithelial development and nutrient uptake. The main effect of STB supplementation increased villus width and jejunal absorptive area, corroborating its proposed prebiotic role through stimulation of beneficial microbial fermentation and SCFA production [17]. Conversely, the narrower villi and reduced villus-to-crypt ratio observed in hens fed the 50:50 wheat–corn diet with STB suggest a potential imbalance in fiber fermentability, where excessive NSP hydrolysis may have led to intestinal irritation or altered microbiota composition. These findings reinforce that the benefits of STB depend on both the type and level of dietary fiber [3,6].
Taken together, these results demonstrate that dietary fiber exerts a stronger and more consistent influence on performance, egg quality, and gut morphology in laying hens compared to STB supplementation. Nevertheless, STB may provide targeted improvements in nutrient absorption and eggshell quality when combined with specific fiber levels. Further research is warranted to clarify the optimal combinations of fiber sources and STB supplementation capable of simultaneously enhancing productivity, intestinal health, and egg quality in commercial laying hens.
5. Conclusions
High dietary fiber levels improved laying hens’ performance, egg quality, and intestinal morphology, and supplementation with 0.01% stimbiotic further enhanced these effects, highlighting it as an effective strategy to optimize production and gut health in commercial laying hens.
Author Contributions
Conceptualization, A.L., R.G., F.P.C., I.K., A.V.d.L., P.S., X.R., G.N. and M.L.; methodology, A.L., I.K., D.V., C.N., E.S., X.R. and D.T.C.; software, M.L., F.P.C., D.V., A.L., and A.V.d.L; formal analysis, I.K., R.G., C.N., E.S., P.S., D.T.C., G.N. and F.P.C.; writing—review and editing, A.L., R.G., F.P.C., I.K., A.V.d.L., G.N. and D.T.C. All authors have read and agreed to the published version of the manuscript.
Funding
This research received no external funding.
Institutional Review Board Statement
The animal study protocol was approved by the Institutional Ethics Committee of the Federal University of Paraiba (protocol code 5673170325 and date of approval.
Informed Consent Statement
Not applicable.
Data Availability Statement
Dataset available on request from the authors.
Acknowledgments
Special thanks are given to AB Vista for providing research materials used for the experiments.
Conflicts of Interest
Xavière Rousseau is employee of AB Vista, the company that supplied Signis® for this study. These co-authors were not involved in the preparation of the manuscript in a manner that would favor the company’s product. All authors declare that the research was conducted independently and without any commercial or financial relationships that could be construed as a potential conflict of interest.
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Table 1.
Feedstuff and chemical composition (g/kg) of diets for Bovans White laying hens.
| Items | Control (corn–soybean) |
Corn–soybean – Low CF |
75:25 wheat–corn |
50:50 wheat–corn |
25:75 wheat–corn |
Wheat – High CF |
|---|---|---|---|---|---|---|
| Wheat | 169.0 | 0.0 | 449.2 | 299.5 | 149.7 | 598.9 |
| Wheat bran | 0.0 | 0.0 | 128.4 | 85.6 | 42.8 | 171.2 |
| Corn | 535.3 | 565.1 | 145.3 | 285.2 | 425.1 | 5.4 |
| Corn gluten meal | 0.0 | 221.0 | 55.3 | 110.5 | 165.8 | 0.0 |
| Soybean meal | 195.1 | 111.3 | 111.5 | 111.4 | 111.4 | 111.5 |
| Soybean oil | 1.3 | 3.7 | 8.7 | 7.0 | 5.3 | 10.3 |
| Coarse limestone | 48.0 | 47.7 | 43.6 | 43.3 | 43.0 | 48.5 |
| Fine limestone | 32.0 | 31.9 | 37.0 | 37.0 | 37.0 | 32.3 |
| Dicalcium phosphate | 8.7 | 6.9 | 7.4 | 7.3 | 7.1 | 7.6 |
| Salt | 2.5 | 1.0 | 1.6 | 1.4 | 1.2 | 1.8 |
| Sodium bicarbonate | 1.0 | 1.0 | 1.6 | 1.4 | 1.2 | 1.7 |
| L-Lysine HCl, 780 g/kg | 1.0 | 2.6 | 2.4 | 2.5 | 2.6 | 2.3 |
| DL-Methionine, 999 g/kg | 1.8 | 1.8 | 2.0 | 1.9 | 1.8 | 2.0 |
| L-Threonine, 985 g/kg | 0.0 | 0.2 | 0.6 | 0.4 | 0.3 | 0.7 |
| L-Tryptophan, 980 g/kg | 0.0 | 0.6 | 0.2 | 0.3 | 0.5 | 0.0 |
| L-Valine, 990 g/kg | 0.0 | 0.0 | 0.4 | 0.2 | 0.1 | 0.5 |
| L-Isoleucina | 0.1 | 0.9 | 0.8 | 0.9 | 0.9 | 0.8 |
| Choline chloride, 600 g/kg | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 | 2.3 |
| Vitamin premix and trace mineral1 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 | 2.0 |
| Stimbiotic (STB) 2 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Total | 1000 | 1000 | 1000 | 1000 | 1000 | 1000 |
| ME kcal/kg | 2830 | 2670 | 2670 | 2670 | 2670 | 2670 |
| Crude protein | 163 | 164 | 164 | 164 | 164 | 165 |
| Met + Cys dig | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 | 7.0 |
| Lys dig | 7.4 | 7.4 | 7.4 | 7.4 | 7.4 | 7.4 |
| Tre dig | 5.3 | 5.3 | 5.3 | 5.3 | 5.3 | 5.3 |
| Tryp dig | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 | 1.8 |
| Val dig | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 | 6.0 |
| Ca | 334 | 334 | 334 | 334 | 334 | 334 |
| Available P | 3.9 | 3.9 | 3.9 | 3.9 | 3.9 | 3.9 |
| Na | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 |
| CF | 23.4 | 37.3 | 29.9 | 32.4 | 34.9 | 27.4 |
| Neutral detergent fiber | 101 | 161 | 132 | 142 | 151 | 122 |
| Acid detergent fiber | 43.2 | 58.2 | 58.4 | 58.3 | 58.3 | 58.4 |
1 Vitamin premix provided per kg of product: vitamin A, 9637 UI; vitamin D3, 2409 UI; vitamin E, 36.1 UI; vitamin K3, 1.93 mg; vitamin B1, 2.59 mg; vitamin B12, 0.016 mg; vitamin B6, 3.61 mg; vitamin B5, 12.95 mg; vitamin B3, 39.0 mg; vitamin B9, 0.90 mg; biotin, 0.09 mg; Trace mineral provided per kg of product: Mn, 64.20 mg; Zn, 59.63 mg; Fe, 45.85 mg; Cu, 9.14 mg; I, 0.927 mg; Se, 0.275 mg. 2 Signis, β−1,4-endo-xylanase and xylooligosaccharides, AB Vista, Marlborough, UK.
Table 2.
Influence of dietary fiber levels and STB supplementation on the performance of laying hens.
Table 2.
Influence of dietary fiber levels and STB supplementation on the performance of laying hens.
| Diets | FI (g/bird/day) |
EP (%) |
EM (g) |
FCR- EM (kg/kg) |
FCR-DZ (kg/dozen) |
BWV (g) |
|
|---|---|---|---|---|---|---|---|
| Means for main effect of STB | |||||||
| STB | + | 117.55a | 94.46a | 56.41a | 2.10a | 1.50a | 6.81a |
| - | 117.27a | 95.05a | 56.87a | 2.08a | 1.48a | 8.08a | |
| Means for main effect of fiber levels | |||||||
| Control (corn– soybean) | 115.65b | 96.10a | 57.92a | 2.01d | 1.45c | 11.07a | |
| Corn–soybean – Low CF | 117.13ab | 91.72c | 54.24c | 2.17a | 1.54a | 6.00b | |
| 50:50 wheat–corn | 118.46a | 94.98ab | 56.68ab | 2.10bc | 1.50ab | 7.44ab | |
| 25:75 wheat–corn | 117.6ab | 93.62bc | 55.52bc | 2.12ab | 1.51ab | 6.16b | |
| 75:25 wheat–corn | 118.30a | 95.97a | 57.66a | 2.07bcd | 1.48bc | 6.13b | |
| Wheat – High CF | 117.49ab | 96.15ª | 57.83ª | 2.05cd | 1.47bc | 7.88ab | |
| Pooled SEM | 0.216 | 0.243 | 0.174 | 0.007 | 0.005 | 0.478 | |
| p-Value | STB | 0.5042 | 0.1637 | 0.0908 | 0.0743 | 0.0697 | 0.16 |
| Fiber levels | 0.0029 | <.0001 | <.0001 | <.0001 | <.0001 | 0.0152 | |
| STB* Fiber levels |
0.4499 | 0.4077 | 0.8681 | 0.4592 | 0.2274 | 0.2084 | |
STB, stimbiotic; CF, crude fiber; FI, Feed intake; EP, Egg production; EM, Egg mass; FCR-EM, Feed Conversion Ratio per egg mass; FCR-DZ, feed conversion dozen eggs; BWV, Body weight variation; a,b,c,d Means in a column, within a group, with different superscripts are significantly different (p < 0.05).
Table 3.
Influence of dietary fiber levels and STB supplementation on the egg quality in laying hens.
Table 3.
Influence of dietary fiber levels and STB supplementation on the egg quality in laying hens.
| Diets | Egg weight (g) |
Yolk (%) |
Albume (%) |
Eggshell (%) |
Yolk color | Haugh unit | Shell thickness (mm) | Specific gravity (g/cm3) |
|
|---|---|---|---|---|---|---|---|---|---|
| Means for main effect of STB | |||||||||
| STB | + | 59.63 | 26.01 | 63.84* | 10.15 | 4.08* | 94.10a | 0.411 | 1.18a* |
| - | 59.90 | 25.88 | 63.94* | 10.17 | 4.17* | 93.70b | 0.411 | 1.16b* | |
| Means for main effect of fiber levels | |||||||||
| Control (corn– soybean) | 60.35a | 26.05a | 63.81a | 10.17a | 4.85a | 93.14d | 0.412ab | 1.159c | |
| Corn–soybean – Low CF | 58.82c | 26.39a | 63.41a | 10.18a | 5.03a | 94.59a | 0.409b | 1.185a | |
| 50:50 wheat–corn | 59.66ab | 25.44a | 64.43a | 10.11a | 4.22b | 94.50ab | 0.410ab | 1.173ab | |
| 25:75 wheat–corn | 59.31bc | 25.76a | 63.97a | 10.27a | 4.76ab | 94.10abcd | 0.411ab | 1.166bc | |
| 75:25 wheat–corn | 60.08a | 26.05a | 63.81a | 10.10a | 3.05c | 93.46cd | 0.410ab | 1.170ab | |
| Wheat – High CF | 60.29a | 26.96a | 63.92a | 10.10a | 2.84c | 93.77bcd | 0.413a | 1.166bc | |
| Pooled SEM | 0.088 | 0.106 | 0.197 | 0.021 | 0.104 | 0.093 | 0.001 | 0.003 | |
| p-Value | STB | 0.1097 | 0.5632 | 0.6779 | 0.5797 | 0.4853 | 0.0222 | 0.8505 | <.0001 |
| Fiber levels | <.0001 | 0.2586 | 0.319 | 0.1419 | <.0001 | <.0001 | 0.0198 | <.0001 | |
| STB* | 0.6820 | 0.3484 | 0.4067 | 0.1310 | <.0001 | 0.0674 | <.0001 | <.0001 | |
| Fiber levels | |||||||||
STB, stimbiotic; CF, crude fiber; *, interaction effect; a,b,c,d Means in a column, within a group, with different superscripts are significantly different (p < 0.05).
Table 4.
Interactions between dietary fiber levels and STB supplementation on the egg quality in laying hens.
Table 4.
Interactions between dietary fiber levels and STB supplementation on the egg quality in laying hens.
| Fiber levels | Yolk color | Shell thickness (mm) | Specific gravity (g/cm3) | |||
|---|---|---|---|---|---|---|
| STB | ||||||
| + | - | + | - | + | - | |
| Control (corn– soybean) | 4.770Aa | 4.936Aab | 0.419Aa | 0.405Bb | 1.154Ac | 1.164Aa |
| Corn–soybean – Low CF | 4.731Aa | 5.337Aa | 0.404Bc | 0.414Aa | 1.212Aa | 1.159Ba |
| 50:50 wheat–corn | 3.704Bc | 4.729Aab | 0.407Ab | 0.413Aa | 1.185Ab | 1.162Ba |
| 25:75 wheat–corn | 5.476Aa | 4.038Bbc | 0.411Ab | 0.411Aab | 1.179Ab | 1.155Ba |
| 75:25 wheat–corn | 3.270Abc | 2.822Ac | 0.406Ab | 0.410Aab | 1.179Ab | 1.162Aa |
| Wheat – High CF | 2.542Ac | 3.131Ac | 0.417Aab | 0.411Aab | 1.165Aac | 1.168Aa |
| Pooled SEM | 0.104 | 0.001 | 0.003 | |||
| p-Value | ||||||
| STB*Fiber levels | <.0001 | <.0001 | <.0001 | |||
AB, uppercase letters compare the inclusion or not of STB within columns; abc, lowercase letters compare dietary fiber levels within rows; significantly different (p < 0.05) according to Tukey’s test.
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