Evaluation Of Growth And Meat Quality Traits Of Matching Combinations Of Royal Chickens By Combining Phenotypic And Metabolome

The traits of the Royal chickensinclude thin skin and bones,delicate meat,low fat content,and unique flavor.Additionally,the three-horned and five-toed symbol can be used as a unique Anti-counterfeiting label。However,due to their small size and slow growth,their production costs are high,which limits the development of the Royal Chicken industry.In order to improve the production performance of Royal chickenswhile maintaining their unique flavor,this experiment conducted back-andforth crosses between the high-legged Royal-chicken HD line and the low-legged Royal chicken LD line,as well as between the SHj line of Ye Jianren Agriculture and the D line and the L line.The hybrid offspring were designated as SHj HD,SHj LD,HDSHj,DHD,DLD,HDD,LHD,LLD,and HDL.The production performance,slaughter performance,and meat quality of the hybrid offspring were measured.The best combination of performance was identified using GC-TOF-MS and UHPLC-QE-MS metabolic profiling of the thymus muscle of the superior hybrid combination.The impact of different metabolites on the quality of the thymus muscle was explored,providing a scientific theoretical basis for hybrid improvement of Royal chickens.The main results of this experiment are as follows:1.Analysis of differences in production performance,slaughter performance,and meat quality among different mating combinations.HDL and HDD had a significant advantage in growth.The HDD male and female chickens reached a weight of 1,312.29 g and 1,141.14 g at 12 weeks of age,respectively,while the HDL male and female chickens reached weights of 1,483.33 g and 1,181.00 g.All of the mating combinations reached the market weight standard at 12 weeks of age.The HDD had the lowest feed-to-weight ratio,with a male ratio of 2.36 and a female ratio of 2.37.Hybridization of Royal-chickens improved the conversion efficiency of feed to meat.HDL had a significant advantage in morphometric parameters such as tibia length and pelvis length.Three nonlinear models,Gompertz,Logistic,and Von-Bertalanffy,were used to mathematically predict the weight change of the mating combinations.The three growth curves had a good fit,with a correlation coefficient greater than 0.995,and could well describe the growth and development patterns of the Royal-chicken mating combinations.The Gompertz model was found to be more suitable for predicting growth and development.Before 8 weeks of age,the growth rate of the 9 mating combinations was slow,but after 8 weeks,the absolute growth rate reached its maximum.Additionally,the 9 mating combinations had a higher half-empty carcass percentage and a higher total empty carcass percentage than other mating combinations,indicating good meat production.The DLD,HDD,and LHD breeds performed better in various slaughter parameters.The drip loss rate of the thigh muscle of each combination was not significantly different,with values ranging from less than 1.5% to 2.5%.The tenderness of the thigh muscle of DLD was the best,and the p H45 min and p H24 h values of all combinations were between 5.8 and 6.2 and 5.7and 5.9,respectively.The meat color of HDD,LHD,and HDL was more red than that of other combinations.The leg muscle of DLD,LHD,and HDL had better water retention and tenderness than other combinations.The p H45 min and p H values of DLD,HDD,and LDD were higher in the meat color.In summary,the DLD,HDD,and LHD breeds had a significant advantage in overall performance.2.Analysis of Metabolic Differences between DLD,DHD,and HDD in Chest Muscle.In this study,a total of 60 differential metabolites were screened between DLD and DHD using VIP > 1 and P < 0.05,of which 19 were upregulated and 41 were downregulated.These metabolites were enriched in pathways such as ascorbate and aldarate metabolism,porphyrin and chlorophyll metabolism,arginine and proline metabolism,glycine,serine,and threonine metabolism,taurine and hypotaurine metabolism,and ABC transporter pathways.In comparison to DLD,a total of 13 differential metabolites were screened out,of which 8 were upregulated and 5 were downregulated,including five acids,two amino acids,two lipids,and some nucleosides.These metabolites were enriched in pathways such as cofactor metabolism,purine metabolism,pyrimidine metabolism,arginine and proline metabolism,D-amino acid metabolism,aldehyde and acid metabolism,vitamin B6 metabolism,nitrogen metabolism,t RNAylation,amino acid metabolism,and ABC transporter pathways.Among these metabolites,2-oxoisovalerate,dihydrozeatine,propionic acid,glutamine,PC(P-18:1(11Z)/20:5(5Z,8Z,11 Z,14Z,17Z)),5-methylquinoline,PC(22:4(7Z,10 Z,13Z,16Z)/15:0),and taurine showed significant differences between DLD,DHD,and HDD.These differential metabolites may be the main reasons for the differences in meat quality and sensory properties between the three genotypes.In conclusion,this study found that DLD,DHD,and HDD were advantages genotypes through determining the production performance,slaughter performance,and meat quality of Royal.Chest muscle metabolic differences were analyzed between the three genotypes,and it was found that 2-oxoisovalerate,dihydrozeatine,propionic acid,glutamine,PC(P-18:1(11Z)/20:5(5Z,8Z,11 Z,14Z,17Z)),5-methylquinoline,PC(22:4(7Z,10 Z,13Z,16Z)/15:0),and taurine could affect meat quality.These results can provide a theoretical basis for the genetic improvement of royal chicken.