Specific gastrointestinal microbiota profiles in Chinese Tan sheep are associated with lauric acid content in muscle.

The biological mechanisms underlying meat quality remain unclear. Currently, many studies report that the gastrointestinal microbiota is essential for animal growth and performance. However, it is uncertain which bacterial species are specifically associated with the meat quality traits. In this study, 16S rDNA and metagenomic sequencing were performed to explore the composition and function of microbes in various gastrointestinal segments of Tan sheep and Dorper sheep, as well as the relationship between microbiota and meat quality (specifically, the fatty acid content of the muscle). In the ruminal, duodenal, and colonic microbiome, several bacteria were uniquely identified in respective breeds, including Agrobacterium tumefaciens, Bacteroidales bacterium CF, and several members of the family Oscillospiraceae. The annotation of GO, KEGG, and CAZYme revealed that these different bacterial species were linked to the metabolism of glucose, lipids, and amino acids. Additionally, our findings suggested that 16 microbial species may be essential to the content of fatty acids in the muscle, especially C12:0 (lauric acid). 4 bacterial species, including Achromobacter xylosoxidans, Mageeibacillus indolicus, and Mycobacterium dioxanotrophicus, were positively correlated with C12:0, while 13 bacteria, including Methanobrevibacter millerae, Bacteroidales bacterium CF, and Bacteroides coprosuis were negatively correlated with C12:0. In a word, this study provides a basic data for better understanding the interaction between ruminant gastrointestinal microorganisms and the meat quality traits of hosts.

A comprehensive microRNA expression profile of the backfat tissue from castrated and intact full-sib pair male pigs.

BACKGROUND: It is widely known that castration has a significant effect on the accumulation of adipose tissue. microRNAs (miRNAs) are known to be involved in fat deposition and to be regulated by the androgen-induced androgen receptor (AR). However, there is little understanding of the relationship between miRNAs and fat deposition after castration. In this study, the high-throughput SOLiD sequencing approach was used to identify and characterize miRNA expression in backfat from intact and castrated full-sib male 23-week-old pigs. The patterns of adipogenesis and fat deposition were compared between castrated and intact male pigs. RESULTS: A total of 366 unique miRNA genes were identified, comprising 174 known pre-miRNAs and 192 novel pre-miRNAs. One hundred and sixty-seven pre-miRNAs were common to both castrated (F3) and intact (F4) male pig small RNA libraries. The novel pre-miRNAs encoded 153 miRNAs/miRNA*s and 141 miRNAs/miRNA*s in the F3 and F4 libraries, respectively. One hundred and seventy-seven miRNAs, including 45 up- and 132 down-regulated, had more than 2-fold differential expression between the castrated and intact male pigs (p-value < 0.001). Thirty-five miRNAs were further selected, based on the expression abundance and differentiation between the two libraries, to predict their targets in KEGG pathways. KEGG pathway analyses suggested that miRNAs differentially expressed between the castrated and intact male pigs are involved in proliferation, apoptosis, differentiation, migration, adipose tissue development and other important biological processes. The expression patterns of eight arbitrarily selected miRNAs were validated by stem-loop reverse-transcription quantitative polymerase chain reaction. These data confirmed the expression tendency observed with SOLiD sequencing. miRNA isomiRs and mirtrons were also investigated in this study. Mirtrons are a recently described category of miRNA relying on splicing rather than processing by the microprocessor complex to generate the RNAi pathway. The functions of miRNAs important for regulating fat deposition were also investigated in this study. CONCLUSIONS: This study expands the number of fat-deposition-related miRNAs in pig. The results also indicate that castration can significantly affect the expression patterns of fat-related miRNAs. The differentially expressed miRNAs may play important roles in fat deposition after castration.

[Polymorphism analysis of the exon 2 of SLA-DQB gene in Xiao Meishan, Zhong Meishan and Yorkshire pigs with PCR-RFLP].

SLA is an important genetic region which influences disease resistance in pigs, and the gene family is one of important candidates for disease resistance and susceptibility. In present research the exon 2 of SLA-DQB gene was amplified and a uniform fragment of 273 bp was obtained in Xiao Meishan, Zhong Meishan and Yorkshire Pigs. The 273 bp PCR product was digested with restriction endonuclease Rsa I and genetic Polymorphism was investigated with PCR-RFLP (restriction fragment length polymorphism). Polymorphic sites were detected at base position 11, 94 and 124 of the exon 2 of SLA-DQB gene. There were two kinds of genotypes in Xiao Meishan pigs, 246 bp/27 bp(AA) and 132 bp/84 bp/30 bp/27 bp(BB), the frequencies of genotype AA and BB are 0.571, and 0.439 respectively. Four kinds of genotypes were found in Zhong Meishan pigs, 246 bp/27 bp (AA), 132 bp/84 bp/30 bp/27 bp(BB), 132 bp/114 bp/27 bp(CC) and 246 bp/132 bp/84 bp/30 bp/27 bp(AB), their frequencies are 0.037, 0.593, 0.037 and 0.333 respectively. Five kinds of genotypes were found in Yorkshire pigs, 246 bp/27 bp(AA), 246 bp/132 bp/114 bp/27 bp(AC), 132 bp/114 bp/27 bp(CC), 246 bp/132 bp/84 bp/30 bp/27 bp(AB) and 273 bp/246 bp/27 bp(AD), the frequencies of five genotypes are 0.467, 0.300, 0.100, 0.100 and 0.033 respectively. Statistical results indicated that there is no favorable allele in Xiao Meishan pig breed; B is the favorable allele in Zhong Meishan and its gene frequency is 0.759; while in Yorkshire pigs A is the favorable allele and its gene frequency is 0.683. Four alleles (A, B, C and D) were found in SLA-DQB locus among three pig breeds; The results of chi 2 showed that four alleles of this locus fit with Hardy-Weinberg equilibrium. The research showed that conservation of Chinese local pig breeds is necessary in order to protect our rich genetic resources and make use of them in the future.