Assessment Of GS Genetic Gain Of Feed Utilization Efficiency In Jinling Yellow-feathered Broilers By Different Methods

In poultry production,feed costs account for more than 70% of the total feeding input.Improving feed efficiency can not only effectively reduce breeding costs,but also reduce the emission of nitrogenous compounds and protect the ecological environment.Genetic breeding is the main way to improve the feed utilization efficiency of broiler breeds.Genomic selectionis a novel generation technology of selection and breeding based on molecular genetic marker information,showing the advantages of realizing early selection,improving genetic gain and increasing the accuracy of selection.Herein,the genetic parameters of RFI and related traits were estimated base on the fast yellow-feathered broiler,the accuracy of different genomic selection methods in estimating the breeding value of feed utilization efficiency traits was compare,and the breeding effect of genomic selection technology on feed utilization efficiency of yellowfeathered broilers was evaluated.In Experiment 1,different methods were employed to estimate the genetic parameters of feed utilization efficiency traits of fast yellow-feathered broilers and to evaluate the accuracy of estimated breeding values of different genomic selection methods.The body weight and feed intake of 3499 yellowfeathered broilers aged 42-56 days were measured and genotyped by 55 K SNP chip.The results showed that the heritability of 42-day-old body weight,56-day-old body weight,average daily gain,average daily feed intake,FCR,RFI and abdominal fat percentage ranged from 0.10 to 0.62.There were differences in heritability estimated by different methods,and the heritability estimated by pedigree information was higher than that based on genomic marker information.A high genetic correlation between RFI and abdominal fat rate and average daily feed intake,and a high genetic correlation between FCR and average daily weight gain and abdominal fat percentage were observed.In SSGBLUP method,adjusting the weight ratio of genotype and pedigree matrix for each trait could effectively improve the prediction accuracy of genomic selection.For individuals with genotype information,PBLUP,GBLUP,SSGBLUP,Bayes A and Bayes B were used to compare the accuracy of 7 traits.The results showed that SSGBLUP method had the best prediction accuracy for 42-day-old body weight,average daily feed intake and FCR,Bayes B had the best prediction accuracy for 56-day-old body weight,average daily gain and RFI,Bayes A demonstrated the best prediction accuracy for abdominal fat percentage,and Bayes B showed the highest average prediction accuracy for 7 traits.For individuals without genetic information,conventional BLUP and SSGBLUP methods were used to compare the accuracy of 7 traits.The average prediction accuracy of SSGBLUP was higher than that of PBLUP.In Experiment 2,yellow-feathered broilers were selected based on RFI and 56-day-old body weight by SSGBLUP method in genomic selection.After selection from G1 to G3 generations,different progress has been made in feed utilization efficiency,growth and carcass traits.In the progress of breeding value,the population RFI decreased by 1.69 g,FCR decreased by 0.04,the body weight increased by 57.66 g,the edible rate increased by 0.21 percentage points,and the abdominal fat percentage decreased by 0.34 percentage points.In the progress of phenotypic value,the body weight of 56-day-old rooster increased by 14.33%,ther FCR increased by 7.86%,the edible rate increased by 9.49%,and the abdominal fat percentage decreased by 32.37%.Besides,the 56-day-old hen’s body weight increased by 7.85%,the FCR decreased by 4.68%,the edible rate increased by 8.98%,and the abdominal fat percentage decreased by34.08%.On the whole,the phenotypic progress was consistent with the breeding value progress as a whole,and the breeding traits were significantly improved.In summary,this study had moderately low heritability for FCR and RFI in yellow-feathered broilers,and SSGBLUP and Bayes B showed the highest prediction accuracy for FCR and RFI,respectively.By using the method of genomic selection and comprehensive index,the selection of yellow-feathered broilers based on RFI and body weight could significantly improve the feed utilization efficiency and meat production rate of yellow-feathered broilers.