Animal Biotechnology最新文献

The gastrointestinal microbiome is pivotal to nutrient utilization and productivity in dairy cattle. This study compared the ruminal and fecal microbiomes of Holstein, Jersey, and Jeju Black cattle using 16S rRNA gene sequencing and three taxonomic classification databases to identify microbial differences across breeds. A total of 25 samples were analysed to evaluate microbial composition, diversity, functional phenotypes, and interactions. Jeju Black cattle exhibited significantly higher ruminal diversity (p < 0.001), whereas Holstein and Jersey cows had more diverse fecal microbiomes. Prevotella, Ruminococcus and Succinivibrio dominated the rumen of commercial breeds, while Methanobrevibacter and Desulfovibrio were enriched in Jeju Black cattle. Amino acid prototrophs were abundant in Holstein and Jersey feces, while sulfur-metabolizing microbial phenotypes predominated in the Jeju Black rumen, with implications for nitrogen metabolism and methane production. Microbial network analysis revealed Mogibacterium as a high-centrality genus in Holstein and Jersey cows, and Anaerovibrio in Jersey cows, potentially linked to propionate production. Jeju Black cattle displayed distinct microbial interactions involving sulphur-reducing and methanogenic bacteria. These results might be showing breed-related microbiome variability, potentially influencing feed efficiency, fermentation, and emissions. However, future work should standardize diets, feeding conditions, sampling methods, and include performance metrics to clarify breed-specificity of microbiome-function relationships.

Body weight and withers height are critical indicators of growth in animals, influencing husbandry practices. In this study, we measured the body weight and withers height of Gannan yaks at different ages (0, 6, 18, 30, 42, 54, 66, and 78 months). Four nonlinear growth models (Logistic, Gompertz, von Bertalanffy, and Brody) were evaluated. The Brody model was identified as the best fit for both body weight and withers height. Females exhibited lower A values and higher K values than males, suggesting earlier onset of puberty. The absolute growth rate (AGR) for males ranged from 16.979 to 0.809 kg/month, while for females, it ranged from 7.202 to 0.588 kg/month. The relative growth rate (RGR) ranged from 74.00 to 0.18% for males and 27.12 to 0.25% for females. Regarding withers height, the AGR and RGR for males ranged from 3.749 to 0.0409 cm/month and 6.69 to 0.034%, respectively. For females, these values ranged from 3.765 to 0.0294 cm/month and 7.02 to 0.026%. Females exhibited fasterGA from birth to 78-months, while males had higher GA in withers height until 17 months, after which females surpassed malesA. Overall, males can achieve larger mature sizes, but females exhibited faster early GA.

This study was designed to assess the genetic diversity and population genetic structure of five sheep breeds in Shanxi Province, China, and to infer the heterosis potential based on their genetic relationships using 20 genome-wide microsatellite markers. Our analysis focused on the local Guangling Large Tail Sheep (GLLTS) breed and four introduced breeds: Hu Sheep (HS), Oula Tibetan Sheep (OLTS), Texel Sheep (TS), and Small Tail Han Sheep (STHLS). The results demonstrated that all microsatellite loci exhibited high levels of polymorphism, making them suitable for evaluating genetic diversity. The genetic parameters indicating that the five populations possess substantial genetic diversity. The genetic variation index (Fst) results among the five populations showed that moderate differentiation between populations. The genetic structure analysis results and the UPGMA clustering diagram were largely consistent. TS exhibited a distant genetic relationship with the other breeds, while HS and GLLTS shared the closest genetic relationship. Based on these genetic evidences, crossing GLLTS with TS or STHLS could potentially achieve a greater degree of heterosis. These research findings provide a molecular genetic foundation for analyzing the genetic diversity of sheep in Shanxi Province and offer guidance for hybrid breeding programs aimed at optimizing breed performance and resource conservation.

It is essential to identify potential genes and genetic variants associated with growth traits to enhance sheep breeding. Previous studies have suggested that the Rho GTPase-activating protein 24 (ARHGAP24) gene may influence the growth of some animals. However, no association has been established between polymorphisms in the ARHGAP24 gene and sheep growth traits. In this study, single-nucleotide polymorphisms (SNPs) in the ARHGAP24 gene of Hu sheep were detected, and functional SNPs associated with Hu sheep growth traits were identified. Twenty-six SNPs were discovered in Hu sheep. Association analysis revealed NC_056059.1:g.455981A > G was significantly associated with average daily gain from six months to one year of age, while NC_056059.1:g.456083 A > G was significantly associated with average daily gain from weaning to six months of age. The relative fluorescence activity (firefly luciferase and sea kidney luciferase) of haplotype GGGG was significantly lower than that of haplotypes GGAA, AAAA and AAGG. Furthermore, ARHGAP24 mRNA expression in the longissimus dorsi muscle of six-months-old sheep was significantly lower than birth sheep. The results showed that NC_056059.1:g.455981A > G and g NC_056059.1:g.456083A > G of ARHGAP24 gene were related to some growth traits of Hu sheep, and ARHGAP24 mRNA was differentially expressed in longissimus dorsi muscle of Hu sheep at different months of age, which could be used as a candidate gene for molecular marker-assisted selection of Hu sheep.

The objective of this study was to perform genome-wide association analysis and thus search for candidate genes for milk production and composition, milk coagulation properties (MCP), and milk protein profile in dairy sheep from a New Zealand flock. After quality control, 45,801 single nucleotide polymorphisms (SNPs) were included in the analysis, 147 ewes, and 470 individual records. A total of 87 SNPs and 55 candidate genes were found across Ovis aries autosomes (OAR) 2, 3, 6, 16, 18, 20, 25, and 26. Of particular importance, were the candidate genes PDZRN4 for milk yield, and BMP2K for contents of α_s1- and α_s2-caseins. No SNPs were found in the casein genes, LALBA or PAEP. Only one SNP was significant for MCP, and overall, the genetic architecture of MCP was similar to that of ratio of casein to calcium, pH, lactose, and the ratio of casein to protein. Further studies with larger flocks and with genomic imputation are required to validate the findings of this study before incorporating markers or genes into breeding programmes.

This study aimed to investigate the expression profiles of the myogenic regulatory genes MYOD1, MYOG, MYF5, MYF6, and MSTN in longissimus dorsi muscle, as well as the correlation of the expression levels of these genes with carcass characteristics and growth performance in the Kivircik and Hungarian Merino sheep breeds. The expression levels of the MYF5, MYF6, and MYOG genes were found to be significantly correlated with the rib proportion, the expression level of the MYOG gene was identified as being the main determinant of variations in the rib proportion in the Kivircik lambs. The regression analysis results revealed that the expression levels of the MYF5 and MSTN genes played an essential role in determining the cold carcass dressing percentage in Hungarian Merino lambs. Further, as a result of the regression analysis, the model including the expression level of the MYF6 gene demonstrated that this gene could be responsible for 36.4% of the differences observed in cold carcass weight. In conclusion, the findings of this study suggest that the expression levels of the MYF5, MYF6, and MYOG genes were associated with various carcass traits, particularly in the Kivircik breed, and these genes hold potential as markers for enhancing breed productivity.

Mastitis, an inflammation of the bovine mammary gland, reduces dairy productivity and poses significant health risks to Ethiopian dairy cattle. This study aimed to identify genomic regions associated with milk somatic cell score (SCS) and estimate its genetic parameters. The dataset included 1647 phenotypic cows, 6964 genotyped animals, and 39,976 single nucleotide polymorphism (SNP) markers. A single-step genome-wide association study (ssGWAS) was conducted, accounting for fixed effects of parity, genomic breed composition, altitude, and lactation stage, and random effects of herd-year-calving-season and permanent environment. Genetic variance using 20 adjacent SNPs sliding windows explaining ≥1% of the total genetic variance were used for candidate genes and quantitative trait loci (QTL) identifications. The estimated heritability of SCS was 0.11 ± 0.06. Genomic regions on BTA 15, 19, and 26 were identified associated with SCS, encompassing 116 genes, including MPP7, MPP8, MMP13, BIRC2, BIRC3, BTRC, SRSF1, and MPO, which are involved in immunity, inflammation, apoptosis, antimicrobial defense, and tissue remodeling. Gene enrichment analysis revealed that the genes are involved collagen catabolic process and IL-17 signaling pathway. These findings provide insights into genomic regions that could be targeted in genomic selection to improve mastitis resistance in Ethiopian dairy cattle.

This study aimed to 1) Establish relationships between feed conversion efficiency (FCE; live weight gain/intake) and several biomarkers in pigs using blood and hair samples, and 2) Investigate the relative FCE performance of pigs from maternal vs. terminal genetic lines fed high vs. low energy diets. 80 male pigs (Large White x Landrace) were fed for 56 days. The terminal genetic line and pigs fed the high energy diet had 5% and 15% higher FCE than the maternal genetic line and pigs fed the low energy diet, respectively. Blood nitrogen isotopic fractionation (Δ¹⁵N; animal δ¹⁵N - feed δ¹⁵N) explained 34% more variation of FCE, compared with the blood insulin‑like growth factor‑1 (IGF‑1). The turnover rate of δ¹⁵N in plasma was faster than δ¹⁵N in blood, suggesting that blood and plasma δ¹⁵N can predict long‑term versus short‑term FCE changes. Pigs fed the high energy diets showed 13% higher live weight gain, 16% greater high standard carcass weight, and 38% higher carcass backfat than those on low‑energy diets. In conclusion, Δ¹⁵N is a more effective FCE biomarker for pigs compared to IGF‑1. Hair samples were less predictive of FCE than blood‑derived biomarkers, suggesting further refinement in the methodology of harvesting hair samples.

This research focused on assessing the molecular prevalence of Bovine Leukemia Virus (BLV) in different cattle farms throughout Khyber Pakhtunkhwa and characterizing the dominant BLV genotypes by analyzing partial sequences of the gp51 gene. A total of 1,250 blood samples were collected from cattle of both sexes, various age groups (<1 year, 1-3 years, 3-5 years, and >5 years), and different breeds (Friesian, Jersey, Sahiwal, Achai, and crossbred) from multiple cattle farms. Of the 1,250 samples tested, BLV was detected in 136 (10.88%) using nested PCR. Risk factor analysis revealed a significantly higher prevalence of BLV in exotic breeds and older cattle. To confirm the findings and genotype the BLV isolates, four PCR-positive samples were sequenced. Phylogenetic analysis identified the isolates as belonging to genotype I, closely related to GI BLV isolates from Japan. Furthermore, the isolates in this study formed a tightly clustered group, suggesting a common origin from an earlier virus introduced into the host population in the study area.