Transgenerational Analysis Of APS Effect On Gene Transcription Of Male Chicken Breeder

Breeding and intensive production can enhance the production performance of broiler chickens, but it is harmful to their immunity. So the use of immunomodulators such as antibiotic growth promoters, is necessary in keeping the health of broiler chickens, but could also cause problems such as drug residues. Research in nutriepigenetics found that nutrients of organisms can modulate the traits of their offsprings. And it is reported that astragalus polysaccharides(APS) can be used as immunomodulator in improving the performance and immunity function of broiler chickens. So we designed and studied the effects of the APS supplement in the diet of male chicken breeder on the performance of commercial broiler chicken as well as the transcriptional regulation of the transgenerational genes. Exp. 1 The effects of APS supplement in the diet of male chicken breeder on the performance of both parental and commercial broilersThe experiment was conducted to study the effects of APS supplement in the diet of male chicken breeder on the performance of commercial broiler chicken and then find out the APS level which could induce the regulation effect on commercial broilers. 160 Cobb 500 male chicken breeder were used in a single-factor design with APS supplement. The 5 levels of APS were 0(Blank), 10^(-5), 10^(-4), 10^(-3), 10^(-2) in the basal diet, respectively, with 4 replicates per group and 8 roosters per replicate. The results showed that APS had no effects on the growth performance as all the roosters were restrictedly fed. No effects were found on the semen quality and hatchability of eggs. The body weight from d 5 to 9 was increased by 10^(-2) APS(P≤0.05) and there was an increasing trend from d 10 to 14. The growth performance of commercial broilers could be improved by 10^(-2) APS supplement into the diet of parental breeder rooster. Exp. 2 The transgenerational analysis of transcriptional information of both parental and commercial broilersWe explored the effects of APS on the function of thymus through screening the differential expression genes of thymus from both parental and commercial broilers by RNA-seq method together with the functional enrichment analysis of GO and KEGG pathway. The 5 levels of APS were 0(Blank), 10^(-5), 10^(-4), 10^(-3), 10^(-2) in the basal diet, respectively. Three replicates of male chicken breeder as well as their commercial broilers were randomly chosen to be slaughtered to get and analyze the thymus sample by RNA-seq method. Based on the results, the amount of Clean Reads from all the 30 samples of thymus was more than 46 million and the results of sequence alignment were good which could be used for the subsequent analysis of biological information such as screening of differential expression gene. Compared to the control group, 313(249 up-regulated, 64 down-regulated), 177(68 up-regulated, 109 down-regulated), 129(66 up-regulated, 63 down-regulated) and 164(84 up-regulated, 80 down-regulated) differential expression genes were found in the parental breeder roosters from group 2-5, respectively. And 52(30 up-regulated, 22 down-regulated), 90(55 up-regulated, 35 down-regulated), 82(52 up-regulated, 63 down-regulated) and 66(44 up-regulated, 22 down-regulated) differential expression genes were found in the commercial broilers, which was less than that in male chicken breeder. Based on the functional characteristics, 4 differential expression genes were chosen to be analyzed by RT-PCR and the results showed that the expressions of these 4 genes were similar to the PRKM value by RNA-seq, which indicated the accuracy of RNA-seq data and the screening of differential expression genes. From the functional enrichment analysis of GO and KEGG pathway, the screened differential expression genes were mainly enriched in the recognition, processing and presentation of antigen which were related to the function of immunity and the cytoskeleton. The differential expression genes which were relevant to the enrichment entry were MHC-I and the cytoskeleton genes and the congruity of all these genes existed between male chicken breeder and commercial broiler chicken. Our study showed that the APS supplement into the diet of male chicken breeder could affect the function of thymus both on themselves and their commercial broilers by regulating the expression of MHC-I and cytoskeleton genes.