The aim of this study was to identify differentially expressed genes, biological processes and metabolic pathways related to adipogenesis and lipogenesis in calves receiving different diets during the cow-calf phase. Forty-eight uncastrated F1 Angus × Nellore males were randomly assigned to two treatments from 30 days of age to weaning: no creep feeding (G1) or creep feeding (G2). After weaning, the animals were feedlot finished for 180 days and fed a single diet containing 12.6% forage and 87.4% corn-based concentrate. Longissimus thoracis muscle samples were collected by biopsy at weaning for transcriptome analysis by RNA-Seq and at slaughter for the measurement of intramuscular fat content (IMF) and marbling score (MS). Animals of G2 had 17.2% and 14.0% higher IMF and MS, respectively (P < 0.05). We identified 947 differentially expressed genes (log2 fold change 0.5; FDR 5%); of these, 504 were up-regulated and 443 were down-regulated in G2. Part of the genes up-regulated in G2 were related to PPAR signaling (PPARA, SLC27A1, FABP3, and DBI), unsaturated fatty acid synthesis (FADS1, FADS2, SCD, and SCD5), and fatty acid metabolism (FASN, FADS1, FADS2, SCD, and SCD5). Regarding biological processes, the genes up-regulated in G2 were related to cholesterol biosynthesis (EBP, CYP51A1, DHCR24, and LSS), unsaturated fatty acid biosynthesis (FADS2, SCD, SCD5, and FADS1), and insulin sensitivity (INSIG1 and LPIN2). Cow-calf supplementation positively affected energy metabolism and lipid biosynthesis, and thus favored the deposition of marbling fat during the postweaning period. Here it was shown, in an unprecedented way, by analyzing the transcriptome, genes, pathways and enriched processes due to the use of creep feeding.

Cattle spread throughout the American continent during the colonization years, originating creole breeds that adapted to a wide range of climate conditions. Population of creole cattle in Peru is decreasing mainly due to the introduction of more productive breeds in recent years. During the last 15 years, there have been a significant progress on cattle genomics. However, little is known about the genetics of the Peruvian creole cattle (PCC) even though its importance to (i) improve productivity in the Andean region, (ii) agricultural labor, and (iii) cultural traditions. In addition, the origin and phylogenetic relationship of the PCC is still unclear. In order to promote the conservation of the PCC, we sequenced for the first time the mitochondrial genome of a creole bull from the highlands of Arequipa, which also possessed exceptional fighting skills and was employed for agricultural tasks. The total mitochondrial genome sequence is 16,339 bp in length with the base composition of 31.43 % for A, 28.64 % for T, 26.81 % for C, and 13.12 % for G. It contains 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and a control region. Among the 37 genes, 28 were positioned on the H-strand and nine were positioned on the L-strand. The most frequently used codons were CUA (Leucine), AUA (Isoleucine), AUU (Isoleucine), AUC (Isoleucine), y ACA (Threonine). Maximum likelihood reconstruction using complete mitochondrial genome sequences clearly demonstrated that the PCC is strongly related to native African breeds, giving insights into the ancestry of PCC. The annotated mitochondrial genome of PCC would serve as an important genetic data set for further breeding work and conservation strategies.

The objective was to evaluate the metabolic and performance differences in primiparous Nellore cows, which became pregnant at 14 or 24 months. Thirty-eight primiparous Nellore cows, which were bred for first pregnancy at 14 or 24-mo of age, with 202 ± 5 days of gestation were divided into two treatments according to breeding age: 14 or 24 months in the breeding season. Cows were evaluated for weight, body condition score (BCS), carcass characteristics, milk yield and blood parameters: glucose, total proteins, albumin, urea, beta-hydroxybutyrate (β-OHB), non-esterified fatty acids (NEFA), progesterone, and for insulin-like growth factor-1 (IGF-1). There was an in-teraction (p < 0.01) between age at first pregnancy and time for body weight, where 24-mo cows were heavier, but both categories loss weight at parturition which concomitant decrease in the BCS (p < 0,01). However, BW of 24-mo remained stable (p > 0.05) after parturition. Milk yield was higher in 24-mo cows (p < 0.01). Interaction between sampling time and breading age was observed for Longissimus muscle area (p < 0.01) and tended for Longissimus muscle depth, where 24-mo cows had greater values in prepartum. Calves born from the cows bred at 24-mo, where was higher (p < 0.01) from 160 days of age until weaning at 240 days. Glucose, urea, total proteins, albumin and NEFA were affected (p < 0.01) by the parturition data-point. There was an interaction (p < 0.01) between breading age and sampling period for β-OHB. Progesterone concentration was greater in 24-mo cows (p < 0.01). It was concluded that primiparous cows that became pregnant at 14 or 24 months of age have different nutritional and metabolic responses.

Description of a novel bovine antimicrobial peptide and its antimicrobial spectrum. RNA isolation and RT-PCR were done from various tissues. DCD peptide was synthesized, and antimicrobial activity was analyzed. Bovine dermcidin gene contains five exons intermittent by 4 introns. Bovine DCD-mRNA was 398 bp with ORF 336 bp. Bovine DCD was expressed in skin and blood. Analysis of the amino acid compositions revealed that cysteine was repeated 6 times indicating the presence of 3 disulfide bonds that play role in the peptide stability. Staphylococcus epidermidis, Streptococcus bovis, and Enterococcus faecalis were affected by Bovine DCD peptide. Highest antimicrobial effect was at 50 and 100 µg/ml. The effect on Escherichia coli and Candida albicans was slightly low. In all bacteria, Bovine DCD peptide activity did not affect by varying pH values, but in Staphylococcus aureus, the activity was affected greatly at pH 4.5 and 5.5. The optimum salt concentrations were 100 and 50 mM NaCl with all bacterial strains and E. coli, respectively. In case of C. albicans, the antimicrobial activity of Bovine DCD peptide decreased with increasing the pH value regardless the NaCl concentration. The pH 6.5 of the sweat buffer was the optimum for the Bovine DCD peptide activity.