Genome-Wide Association Study of Abdominal Fat in Wenshang Barred Chicken Based on the Slaf-Seq Technology

Chicken abdominal fat (AF) is an economically important trait, and many studies have been conducted on genetic selection for AF. However, previous studies have focused on detecting functional chromosome mutations or regions using gene chips. The present study used the specific-locus amplified fragment sequencing (SLAF-seq) technology to perform a genome-wide association study (GWAS) on purebred Wengshang Barred chicken. A total of 1,286,715 single-nucleotide polymorphisms (SNPs) were detected, and 175,211 SNPs were selected as candidate SNPs for genome-wide association analysis using TASSEL general linear models. Two SNPs markers reached genome-wide significance. Of these, rs7943847, rs127627362 were significantly associated with AF at 120 days. These SNPs are close to eight genes (SLC16A6, ARSG, WIPI1, PRKAR1A, FAM20A, ABCA8, ABCA9, CPQ,). These results would enrich the studies on AF and promote the use of Chinese chicken, especially the Wenshang Barred chicken.(AU)

Effect of Plant Essential Oil on Growth Performance and Immune Function During Rearing Period in Laying Hens

The effects of plant essential oil (PEO) on the production performance and immune function of laying hens were evaluated to provide theoretical basis for promoting the natural plant extracts. Eight thousand 1-day-old healthy laying hens were randomly divided into a control group or PEO group, with four replicates per treatment and 1000 hens per replicate. The PEO diet was supplemented with 3g/kg plant extract. Diets were fed for 56 days. The tibia length and keel length were detected on an empty stomach at the end of the trial. Blood samples were collected on the 28th and 56th days to detect the level of C3, C4, IL-1, IL-2, IL-17 and immunoglobulin in the serum. The results showed that, compared with the control, PEO supplementation significantly increased the weight gain rate (WGR) at the 2nd, 4th, 5th and 7th week (p 0.05), and decreased the WGR at the 3rd and 6th week. The tibial length was significantly increased at the 3rd, 5th, 6th and 7th week (p 0.01), and also the keel length at the 5th and 7th week in PEO group. The concentration of IgG and IgM also significantly influenced with PEO supplementation, but there was no significant difference in the complements, C3 and C4, and the IL levels between days 28 and 56. Moreover, no significant difference was observed in body weight and immune organ on day 56. Therefore, we conclude that the addition of PEO could improve the production performance and immune function in laying hens.(AU)

Effect of Plant Essential Oil on Growth Performance and Immune Function During Rearing Period in Laying Hens

The effects of plant essential oil (PEO) on the production performance and immune function of laying hens were evaluated to provide theoretical basis for promoting the natural plant extracts. Eight thousand 1-day-old healthy laying hens were randomly divided into a control group or PEO group, with four replicates per treatment and 1000 hens per replicate. The PEO diet was supplemented with 3g/kg plant extract. Diets were fed for 56 days. The tibia length and keel length were detected on an empty stomach at the end of the trial. Blood samples were collected on the 28th and 56th days to detect the level of C3, C4, IL-1, IL-2, IL-17 and immunoglobulin in the serum. The results showed that, compared with the control, PEO supplementation significantly increased the weight gain rate (WGR) at the 2nd, 4th, 5th and 7th week (p 0.05), and decreased the WGR at the 3rd and 6th week. The tibial length was significantly increased at the 3rd, 5th, 6th and 7th week (p 0.01), and also the keel length at the 5th and 7th week in PEO group. The concentration of IgG and IgM also significantly influenced with PEO supplementation, but there was no significant difference in the complements, C3 and C4, and the IL levels between days 28 and 56. Moreover, no significant difference was observed in body weight and immune organ on day 56. Therefore, we conclude that the addition of PEO could improve the production performance and immune function in laying hens.

Effect of Heat Stress on the Expression of GABA Receptor mRNA in the HPG Axis of Wenchang Chickens

We investigated the effect of heat stress (HS) on the expression of the GABA receptor in the hypothalamic-pituitary-gonadal (HPG) axis of Wenchang chickens. Real-time quantitative RT-PCR (qRT-PCR) was used to quantify the GABA receptor mRNA levels along the HPG axis of chickens under HS (40±0.5 °C) for 1-6 weeks. Our results showed that the expression of GABAA and GABAB receptor at the mRNAs levels in the tissues of HPG axis exhibited fluctuation and variability. After HS, the mRNA level of GABAA receptor was significantly reduced in the hypothalamus of 1-week-old and in the pituitary of 3-week-old chickens, but significantly increased in the pituitary of 1-, 4-, and 5-week-old chickens. The GABAB receptor mRNA level significantly declined in the hypothalamus of 1-week-old and in the pituitary of 3-week-old chickens, but was significantly upregulated in the pituitary and testis of 1- and 2-week-old chickens. At other time points, the expressions of GABAA receptor and GABAB receptor showed no significant differences compared with control group. These results indicated that the levels of GABAA receptor and GABAB receptor mRNAs varied in different tissues of the HPG axis in chickens of different ages, displaying temporal and spatial variations. GABA receptor behaved as a positively-regulated gene by HS, i.e., its mRNA was increased by HS; similarly, it was a negatively-regulated gene by HS, when its expression was reduced by HS.

Effect of Heat Stress on the Expression of GABA Receptor mRNA in the HPG Axis of Wenchang Chickens

We investigated the effect of heat stress (HS) on the expression of the GABA receptor in the hypothalamic-pituitary-gonadal (HPG) axis of Wenchang chickens. Real-time quantitative RT-PCR (qRT-PCR) was used to quantify the GABA receptor mRNA levels along the HPG axis of chickens under HS (40±0.5 °C) for 1-6 weeks. Our results showed that the expression of GABAA and GABAB receptor at the mRNAs levels in the tissues of HPG axis exhibited fluctuation and variability. After HS, the mRNA level of GABAA receptor was significantly reduced in the hypothalamus of 1-week-old and in the pituitary of 3-week-old chickens, but significantly increased in the pituitary of 1-, 4-, and 5-week-old chickens. The GABAB receptor mRNA level significantly declined in the hypothalamus of 1-week-old and in the pituitary of 3-week-old chickens, but was significantly upregulated in the pituitary and testis of 1- and 2-week-old chickens. At other time points, the expressions of GABAA receptor and GABAB receptor showed no significant differences compared with control group. These results indicated that the levels of GABAA receptor and GABAB receptor mRNAs varied in different tissues of the HPG axis in chickens of different ages, displaying temporal and spatial variations. GABA receptor behaved as a positively-regulated gene by HS, i.e., its mRNA was increased by HS; similarly, it was a negatively-regulated gene by HS, when its expression was reduced by HS.(AU)