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Small ruminants farming plays an important role in the livelihood of a large part of the population. Herein we aimed to analyze the effects of single nucleotide polymorphisms in PRKAA2 gene on the growth-related traits of Hu sheep and Dorper sheep. The body weight and body type of 1254 sheep were measured at 80, 100, 120, 140, 160 and 180d, and 37620 phenotypic data were collected. RT-qPCR analysis was performed to test PRKAA2 gene expressed in different tissues of sheep, with the highest expression level in spleen, followed by kidney. In the present study, the PRKAA2 gene sequencing revealed one polymorphism located on Chr1 (Oar_rambouillet_v1.0), termed as chr1:32832382 G > A, and were significantly associated with growth traits of sheep (p < 0.05). The body weight, body length, chest circumference, and cannon circumference of individuals with AA genotype were significantly higher than those with the GG and GA genotypes (p < 0.05). Our findings reveal that PRKAA2 gene could be used as a marker-assisted selection to improve the growth-related traits of sheep. [ABSTRACT FROM AUTHOR]

The development of the rumen is a critical physiological challenge in newborn ruminants. However, the molecular mechanism underlying different stages of rumen development in sheep remains poorly understood. Here, RNA sequencing and bioinformatics analysis were performed to compare the transcription profiles of rumen development at 7, 28 and 56 days of birth (D7, D28 and D56). We identified 1246, 2257 and 627 differentially expressed genes (DEGs) between D7 and D28, between D7 and D56, between D28 and D56, respectively. Also, 70 DGEs were co-expressed at these three time points. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated most DEGs mainly related to transporter activity, channel activity and metabolism pathways. Noteworthy, the expression levels of most genes (CA4, CA9, CA12 and CA14) in nitrogen metabolic pathways were negatively correlated with the papilla length and width, but the papilla length and width were positively correlated with the expression of genes (PLA2G3, SLC26A9, SLC34A3) in ion transport pathway, suggesting that these genes may be involved in nitrogen metabolic and ion transport pathway and thus affect rumen development. These results provide new insight into the changes in RNA expression at different time points of rumen development in Hu sheep. [ABSTRACT FROM AUTHOR]

Feed efficiency makes up a large part of sheep production, which also has a crucial impact on the economic benefits of producers. This study explores the polymorphism of Adenylyl cyclase 8 gene associated with feed efficiency and detects the expression characteristics of ADCY8 in ten tissues of Hu sheep. The polymorphism of ADCY8 was recognized by using PCR amplification and Sanger sequencing, KASPar technology was used for genotyping subsequently, and the relationship between SNP and RFI is also studied. The results indicated that an intronic mutation g.24799148 C > T (rs 423395741) was identified in ADCY8, and association analysis showed that the SNP g.24799148 C > T (rs 423395741) was significantly associated with RFI at 100–120, 100–140, 100–160, and 100–180 days (p < 0.05). The quantitative real-time PCR (qRT-PCR) result showed that ADCY8 was expressed in ten tissues, and the expression of ADCY8 gene in rumen tissue was significantly higher than in the other tested tissues. Therefore, these results indicated that the ADCY8 mutation locus may be used as a candidate molecular marker for evaluating the feed efficiency of Hu sheep. [ABSTRACT FROM AUTHOR]

Hu sheep is an excellent short fat-tailed breed in China. Fat deposition in Hu sheep tail affects carcass quality and consumes a lot of energy, leading to an increase in feed cost. The objective of this study was to analyze the effects of HMGA1 polymorphism on tail fat weight in Hu sheep. Partial coding and non-coding sequences of HMGA1 were amplified with PCR and single nucleotide polymorphisms (SNP) of HMGA1 in 1163 Hu sheep were detected using DNA sequencing and KASPar technology. RT-qPCR analysis was performed to test HMGA1 expression in different tissues. The results showed that the expression of HMGA1 was higher in the duodenum, liver, spleen, kidney, and lung than in the heart, muscle, rumen, tail fat, and lymph. A mutation, g.5312 C > T, was detected in HMGA1; g.5312 C > T was significantly associated with tail fat weight, relative weight of tail fat (body weight), and relative weight of tail fat (carcass) (p < 0.05). The tail fat weight of the TT genotype was remarkably higher than that of the CC and TC genotypes. Therefore, HMGA1 can be used as a genetic marker for marker-assisted selection of tail fat weight in Hu sheep. [ABSTRACT FROM AUTHOR]

The early weaning and starter feeding have significant effects on lamb growth and digestive tract development. However, it is not clear whether the expression of IGF-1/IGF-1R genes could be affected by feeding starter and weaning. Therefore, a total of 102 Hu male neonatal lambs were randomly divided into 3 groups: fed with starter at 42d + weaned at 56d (group A), fed with starter at 7d + weaned at 28d (group B) and fed with starter at 7d + weaned at 56d (group C), to explore the effects of starter feeding and weaning age on developmental expressions of IGF-I gene in liver and IGF-IR gene in rumen of Hu sheep. The results showed that IGF-I and IGF-IR genes were expressed extensively in various tissues of lambs, the expression of IGF-I was significantly higher in liver (p < 0.01), while the expression of IGF-IR was higher in rumen among gastrointestinal tissues. The mRNA level of IGF-I of group C was strikingly higher than that of group A at 28, 70, and 84d (p < 0.01) in liver, respectively. Rumen mRNA level of IGF-IR of group C was prominently higher than that of group A at 70d and 84d (p < 0.05), respectively. However, IGF-IR expression of group A was higher than that of group C at 14 and 42d (p < 0.05). The mRNA level of IGF-I of group B was significantly higher than that of group C at 42, 56, 70, and 84d (p < 0.01) in liver, while IGF-IR expression of group B was higher than that of group C at 70d (p < 0.01). In conclusion, early weaning and starter feeding affected liver IGF-I mRNA and rumen IGF-IR mRNA expression. [ABSTRACT FROM AUTHOR]