Effect Of Methionine Level On Production Performance Of Hybrid Chicken And Study On Differential Expression Gene Of Leg Muscle

ObjectiveIn order to explore the most suitable methionine content for the growth stage of 5-13 week-old hybrid chickens,and to explore the relationship between leg muscle-related regulatory genes and muscle growth and metabolic pathways,and the molecular mechanism of regulatory differences in muscle growth and metabolism of hybrid chickens at the age of 5-13 weeks.MethodsTrial 1.126 healthy 4-week-old hybrid chickens and 63 hens each(?Big bone chicken×?Recessive white feather broiler),were randomly divided into three groups according to 2 × 3 factor,each treatment was divided into 3 groups,each treatment was divided into 3 duplications,7 for each repetition.Three treatment groups were fed with three different levels of methionine diets for 10 weeks to determine their growth performance.Trial 2.After feeding to 49 days and 91 days of age,3 broiler hens in each group were randomly selected and their slaughtering performance was determined after fasting for 12 hours.Trial 3.Sample of leg muscle from three chickens in each group of 91-day-old cocks,and perform RNA-Seq experimentResults1.The effect of dietary methionine level on the average feed intake of male hens aged 5 to 7 weeks was significant,while that of the high level group was significantly lower than that of the other two groups(P < 0.01).The average daily gain and feed / weight ratio had no significant effect on the cocks and hens.The average feed intake of cocks and hens at the age of 8-13 weeks showed that the low level group is higher than high level group(P < 0.01).The low level group was higher than the middle level group,the difference was significant(P < 0.05)and there was significant difference between the middle level group and the high level group(P < 0.05).There was no significant difference in average daily gain and feed-weight ratio between cocks and hens(P > 0.05).The high feed-to-weight ratio were better than those with high feed-to-weight ratio.2.The results of slaughtering performance of 49-day-old rooster showed that the ratio of cock leg in the middle level group was significantly higher than that in the low level group(P< 0.05).The leg muscle rate in the middle level group was higher than that in the high level group(P < 0.05),and the breast muscle rate in the middle level group was significantly higher than that in the low level group,but there was no significant difference in other indexes such as slaughter rate.There was no significant difference in seven indexes among hens(P> 0.05).The results of slaughtering performance of 91-day-old rooster showed that the ratio of leg to leg in the middle level group was higher than that in the high level group(P < 0.05),the leg muscle rate in the middle level group was higher than the high level group(P < 0.05),and the breast muscle rate in the middle level group was higher than that in the high level group(P < 0.01).There was no significant difference in other indexes;The leg ratio in the horizontal group was significantly lower than that in the other two groups,but the other indexes,such as the slaughtering rate of the hens,were not significantly affected.3.Nine samples of leg muscle of 91-day-old hybrid rooster were sequenced.29265 transcripts were expressed in leg muscle and 11 genes were co-expressed in three treatment groups.There were 831 differentially expressed genes in H group and M group,587 up-regulated genes and 244 down-regulated genes,among which 247 genes were up-regulated and 173 genes were down-regulated in L group and M group.There were 715 differentially expressed genes between H group and L group,of which 442 genes were up-regulated and 273 genes were down-regulated.These genes were analyzed by GO and KEGG.It was found that the biological processes included actin cytoskeleton,muscle phylogeny and so on and the enriched signaling pathways include adrenergic signal transduction,fatty acid prolongation,tyrosine metabolism,nicotinic acid and nicotinamide metabolism,etc.In order to screen the differential genes,there are 19 candidate genes were obtained.Conclusions1.The level of methionine had effect on the growth performance of aged 5-13 weeks hybrid chicken.The content of methionine(0.39%)was more beneficial to increase the average daily intake of hybrid chickens aged 5-7 weeks,and the content of methionine(0.28%)was more beneficial to increase the average daily intake of hybrid male hens aged 8-13 weeks.2.Methionine diet had an effect on slaughter performance of 49 and 91-day-old hybrid roosters.The content of methionine in the medium level group is more beneficial to improve the pectoral muscle rate,leg muscle rate and leg ratio of hybrid roosters.3.Methionine level in diet caused significant changes in the leg muscle transcriptome of hybrid rooster,in which the differentially expressed genes were mainly concentrated in the pathways related to muscle cell development,myosin protein synthesis,amino acid metabolism and other pathways.