dPRLR causes differences in immune responses between early and late feathering chickens after ALV-J infection.

To understand the differences in immune responses between early feathering (EF) and late feathering (LF) chickens after infection with avian leukosis virus, subgroup J (ALV-J), we monitored the levels of prolactin, growth hormone and the immunoglobulins IgG and IgM in the serum of LF and EF chickens for 8 weeks. Moreover, we analysed the expression of immune-related genes in the spleen and the expression of PRLR, SPEF2 and dPRLR in the immune organs and DF-1 cells by qRT-PCR. The results showed that ALV-J infection affected the expression of prolactin, growth hormone, IgG and IgM in the serum. Regardless of whether LF and EF chickens were infected with ALV-J, the serum levels of the two hormones and two immunoglobulins in EF chickens were higher than those in LF chickens (P < 0.05). However, the expression of immune-related genes in the spleen of positive LF chickens was higher than that in the spleen of positive EF chickens. In the four immune organs, PRLR and SPEF2 expression was also higher in LF chickens than in EF chickens. Furthermore, the dPRLR expression of positive LF chickens was higher than that of negative LF chickens. After infection with ALV-J, the expression of PRLR in DF-1 cells significantly increased. In addition, overexpression of PRLR or dPRLR in DF-1 cells promoted replication of ALV-J. These results suggested that the susceptibility of LF chickens to ALV-J might be induced by dPRLR.

A novel SNP of MYO1A gene associated with heat-tolerance in Chinese cattle.

With the advent of global climate change, heat-tolerance is becoming more and more important to the sustainability of animal husbandry production systems. Previous studies have shown that MYO1A gene associated with pigmentation may be closely related to heat-tolerance in cattle. In this study, a novel missense mutation (NC_037332.1 g.56390345 A > G) was first detected in MYO1A in 891 individuals of 35 cattle breeds, which transformed the amino acid isoleucine into valine. The purpose of this study was to determine the allele frequencies distribution of this locus in Chinese indigenous cattle and to analyze the relationship between this locus and heat-tolerance. Further analysis showed that frequency of wild allele A decreased gradually from northern cattle to southern cattle, whereas frequency of mutant type allele G showed the opposite pattern, which was consistent with the distribution of various climatic conditions of China. Additionally, association analysis was carried out between genotypes and four climatic conditions (annual mean temperature (T), relative humidity (H), temperature-humidity index (THI) and average annual sunshine hours (100-cloudiness) (SR)). Analysis results showed that genotypes were significantly correlated with climatic conditions. Therefore, our results suggest that the novel SNP (rs209559414) is related to heat-tolerance trait of Chinese indigenous cattle.

Genetic Characteristics and Pathogenicity of a Novel Porcine Deltacoronavirus Southeast Asia-Like Strain Found in China.

Farmers involved in the lucrative pork trading business between China and Southeast Asian countries should be aware of a recently discovered novel porcine deltacoronavirus (PDCoV) in Guangxi province, China. A PDCoV strain, CHN/GX/1468B/2017, was isolated from the small intestinal contents of piglets with diarrhea from this region, with a titer of 1 × 108.0 TCID50/mL on LLC-PK cells. The full-length genome sequence consists of 25,399 nt as determined by next-generation sequencing and this was deposited in the GenBank (accession number MN025260.1). Genomic analysis showed that CHN/GX/1468B/2017 strain had 96.9~99.4% nucleotide homology with other 87 referenced PDCoV strains from different areas, and contained 6 and 9-nt deletions at positions 1,733~1,738 and 2,804~2,812, respectively, in the ORF1a gene. Phylogenetic analyses based on the whole gene sequence as well as S protein and ORF1a/1b protein sequences all showed that this strain was closely related to the Southeast Asia strain. When 7-day-old piglets were inoculated orally with the CHN/GX/1468B/2017 strain, they developed severe diarrhea, with a peak of fecal viral shedding at 4 days post-infection. Although no death or fever were observed, the CHN/GX/1468B/2017 strain produced a wide range of tissue tropism, with the main target being the intestine. Importantly, the VH:CD ratios of the jejunum and ileum in infected piglets were significantly lower than controls. These results indicate that CHN/GX/1468B/2017, isolated in China, is a novel PDCoV Southeast Asia-like strain with distinct genetic characteristics and pathogenicity. This finding enriches the international information on the genetic diversity of PDCoV.

The Expression Profiles of mRNAs and lncRNAs in Buffalo Muscle Stem Cells Driving Myogenic Differentiation.

Buffalo breeding has become an important branch of the beef cattle industry. Hence, it is of great significance to study buffalo meat production and meat quality. However, the expression profiles of mRNA and long non-coding RNAs (lncRNA) molecules in muscle stem cells (MuSCs) development in buffalo have not been explored fully. We, therefore, performed mRNA and lncRNA expression profiling analysis during the proliferation and differentiation phases of MuSCs in buffalo. The results showed that there were 4,820 differentially expressed genes as well as 12,227 mRNAs and 1,352 lncRNAs. These genes were shown to be enriched in essential biological processes such as cell cycle, p53 signaling pathway, RNA transport and calcium signaling pathway. We also identified a number of functionally important genes, such as MCMC4, SERDINE1, ISLR, LOC102394806, and LOC102403551, and found that interference with MYLPF expression significantly inhibited the differentiation of MuSCs. In conclusion, our research revealed the characteristics of mRNA and lncRNA expression during the differentiation of buffalo MuSCs. This study can be used as an important reference for the study of RNA regulation during muscle development in buffalo.

Mitogenome Diversity and Maternal Origins of Guangxi Cattle Breeds.

Guangxi Province is located in the southernmost region of China, adjacent to the hotspot that is considered to be the putative migratory corridor or domestication area for Chinese indicine cattle. Here, we investigated the evolutionary status of Guangxi native breeds, Longlin (n = 21), Nandan (n = 18), and Weizhou cattle (n = 17) using mitogenome sequencing. Our results show that Bos indicus sub-haplogroup I1a predominates in Guangxi cattle breeds. Population structure by multidimensional-scaling analysis significantly differentiates Weizhou from the other two breeds (Longlin and Nandan). Moreover, the mtDNA haplotype composition and FST values indicate that the formation of Longlin and Nandan breeds may have been affected by Indian indicine, whereas, Weizhou island might have preserved pure Chinese indicine cattle due to its geographical isolation. We speculate that following the initial entry of zebu into southern China, the subsequent introgression of Indian indicine may have influenced the matrilineal origin of local breeds in southwestern China.

A Missense Mutation of the HSPB7 Gene Associated with Heat Tolerance in Chinese Indicine Cattle.

The small heat shock proteins (HSPB) are expressed in response to heat stress, and the heat shock protein family B (small) member 7 (HSPB7) gene has been reported to play an important role in heat tolerance pathways. Only a missense mutation (NC_037329.1: g.136054902 C > G: p.Ala69Gly) was identified in the HSPB7 gene in indicine cattle, which might be a candidate mutation associated with the heat tolerance. Here, we explore the allele frequency of this mutation in 774 individuals belonging to 32 Chinese indigenous cattle breeds using polymerase chain reaction (PCR) and DNA sequencing methods. The distribution of alleles of NC_037329.1: g.136054902 C > G displays significant geographical difference across native Chinese cattle breeds that the allele C was dominant in northern cattle groups, while allele G was dominant in southern indicine cattle groups. Additionally, the association analysis indicated that the G allele was significantly associated with mean annual temperature (T), relative humidity (RH), and temperature humidity index (THI) (p < 0.01), suggesting that cattle carrying allele G were distributed in regions with higher T, RH, and THI. Our results demonstrate that the mutation of the HSPB7 gene in Chinese indicine cattle might be a candidate gene associated with the heat tolerance.

A field study on artificial insemination of swamp and crossbred buffaloes with sexed semen from river buffaloes.

Sex preselection by flow sorting of X- and Y-sperm has been proven to be an efficient and economically feasible strategy for use in Holstein dairy cow breeding, and previous reports have demonstrated the feasibility of altering the sex ratio in buffalo species by using sexed semen in either artificial insemination or IVF. However, because buffalo reproductive physiology and farm management are different from Holsteins, factors involved in artificial insemination by sexed semen need to be further addressed before being applied in buffalo breeding at village-level husbandry. In this study, a total of 4521 swamp or crossbred (F1 or F2) buffaloes with natural estrus were inseminated with X-sorted sperm from river buffaloes, resulting in a 48.5% (2194 of 4521) pregnancy rate and 87.6% (1895 of 2163) sex accuracy in the derived calves. The pregnancy rate obtained with sexed semen from Murrah bulls was higher than that of Nili-Ravi, 52.5% (895 of 1706) versus 46.1% (1299 of 2815; P < 0.01), respectively. Also, significant variations were seen in pregnancy rates from inseminations performed in different seasons (P < 0.01) and by different technicians (P < 0.01). In contrast to Holsteins, no difference was seen in the pregnancy rate between heifers and parous buffalo cows, and buffalo cows with different genetic backgrounds (swamp type, crossbred F1 and F2) showed similar fertility after insemination with sexed semen. The findings in the present study under field conditions pave the way for application of sexing technology to buffalo breeding under village-level husbandry and diverse genetic backgrounds.