Effects Of High-energy And Low-nitrogen Diets On The Quality Of Eliminated Gushi Chicken Eggs And Related Genetic Screening

Gushi chickens an excellent local variety in China which has beautiful appearance and strong ability of adaptation with high quality of meat and eggs.After an egg production cycle in the production practice,we try to increase the energy level and reduce the protein level one month before on the market for making the carcass traits and body fat deposition of the old chickens more suitable for the market demand of high-quality chickens.600 chickens at the age of 42 weeks which were similar and healthy were randomly divided into 2 groups(6 replicates in each group,50 in each replicate)for the feeding experiment.In the 45-day feeding experiment,the control group was fed the corn glutinous basic diet(ME2.62 MJ/kg;CP 15.54%),and the test group was fed the corn glutinous high-energy low-protein diet(ME2.78 MJ/kg;CP 14.51%).The body size indexes,slaughtertraits,meat quality,phenotype and biochemical parameters of 42-week-old experiment chickens were respectivelydetected.What’s more,we took transcriptome sequencing with chest muscle tissue of two groups by high-throughput sequencing and screened out differently expressed genes between the two groups.Differential genes were analyzed by GO and KEGG enrichment to find key genes affecting fat deposition.The results are as follows:Experiment 1:Effects of high energy and low protein diet on body size and carcasses of Gushi chicken at the later stage of egg productionThere was no significant difference in body length,shank circumference,keel length and chest width between the experimental group and the control group(P>0.05).The chest depth of the chicken in the experimental group was significantly higher than that in the control group(P<0.05).The high-energy and low-protein diet had no significant effect on the live weight,slaughter weight,slaughter rate,semi-net sputum rate,total net sputum rate and abdominal fat rate of the spent Gushi chicken(P>0.05).Compared with the control group,the difference in intermuscular fat bandwidth between the high-energy and low-protein groups was significantly lower(P<0.05).Experiment 2:Effects of high-energy and low-protein diets on the spent Gushi chicken meat quality and serum related indicatorsThere was significant difference in breast muscle moisture content and leg muscle dry matter between the experimental group and the control group(P<0.05).The IMF in the control group was higher than that in the experimental group but the difference was not significant(P>0.05).The PH values of the pectoral muscles at 45 min and 24 h were not significantly different between the two groups.(P>0.05).A total of 17 amino acids were detected in the two groups.There was no significant difference in the ratio of non-essential amino acids to total amino acids,the proportion of essential amino acids to total amino acids,and the proportion of essential amino acids to non-essential amino acids between the two groups(P>0.05).A total of 22 species of saturated and unsaturated fatty acids were detected in the test and control groups.There were significant difference in C20:0,C20:1,C22:0,C20:4n6 between two groups(P<0.05).The other fatty acid content and inosinic acid content were not significantly different between the two groups.(P>0.05).The total protein(TP),albumin(ALB),globulin(GLO),total cholesterol(TC),and triglyceride levels(TG)in the test group were higher than those in the control group,but the difference were not significant(P>0.05).Among them,the white ball ratio(A/G),glucose(GLU),and high-density lipoprotein(HDL-C)in the control group were higher that in the experiment group without significant difference(P>0.05).The intermuscular fat bandwidth was significantly positively correlated with total cholesterol(TC),high density lipoprotein(HDL-C),and low density lipoprotein LDL-C(P<0.01);subcutaneous fat thickness and total protein(TC),white Protein(ALB),globulin(GLO),and glucose(GLU)were significantly negatively correlated(P<0.01).Experiment 3:Determination of quality traits in the elimination of Gushi eggs by high-energy and low-protein dietsThe egg weight and eggshell rate of the experimental group and the control group were significantly different(P<0.05),and the other egg quality indicators were not significantly different.The high-energy and low-protein diet can significantly increase the egg weight and eggshell rate of eggs in the late egg-producing period,and the Hastelloy unit and protein height belong to the A-class category.Compred chickens ive analysis shows that the test group has better egg quality than the control group.Experiment 4 Screening of Differential Genes in Chest Muscle of Gushi Chicken with Different DietsHigh-throughput transcriptome sequencing technology was used to successfully perform RNA-Seq sequencing on the muscles of Gushi chickens in the late two-stage laying period.The expression level of the detected genes showed that the total expression of 13486 genes was quantitatively analyzed.A total of 171 differential genes were screened,of which 99 were up-regulated and 72 were down-regulated.Selected differential genes were conducted enrichment analysis using GO and KEGG,and these genes which were took GO enrichment analysis were annotated into 73 GO terms.Eight of the biological process function terms are annotated,with the regulation of leukocyte chemotaxis being the primary secondary term.There are 19 annotations in the cellular component term,of which the extracellular region is the most important secondary term.In the molecular function term,46 terms were annotated,and the serine-type endopeptidase activity was the most important secondary term.Meanwhile six genes related to fat deposition,HABP2、CD36、ABCA12、COL6A1、ACAA2、ETNPPL、FAS,which were found to be the focus of follow-up research.