Study on Optimal Dietary Metabolizable Energy and Crude Protein Levels for Xueshan Breeding Hens during Growing Period
This study was conducted to investigate the effects of dietary metabolizing energy(ME)and crude protein(CP)levels on growth performance,body size traits,slaughter performance,ovarian index,laying age,primary egg weight and intestinal microflora of Xueshan breeding hens during growing period,in order to determine the appropriate dietary ME and CP levels.Three ME levels(10.88,11.30 and 11.72 MJ/kg)and three CP levels(12.50％,14.00％and 15.50％)were set in the experiment using a 3x3 two-factor completely randomized experimental design.At the same time,1 458 healthy Xueshan breeding hens with similar body weight at the end of 6 weeks of age were selected and randomly divided into 9 groups with 9 replicates per group and 18 chickens per replicate.The experiment lasted for 10 weeks,and the growth performance and slaughter samples were measured at the end of 16 weeks of age;the laying age and primary egg weight were tracked from 20 weeks of age.The results showed as follows:1)with the increase of dietary ME and CP lev-els,the final body weight and average daily gain of Xueshan breeding hens during growing period were signifi-cantly increased(P＜0.05),and the ratio of feed to gain was significantly decreased(P＜0.05).There were significant interaction effects between dietary ME and CP level on final body weight and average daily gain(P＜0.05).2)The body slope length,fossil bone length and slaughter rate in medium and high ME groups were significantly higher than those in low ME group(P＜0.05);the body slope length and fossil bone length in high protein group were significantly higher than those in low protein group(P＜0.05),and the eviscerated rate was significantly higher than that in medium and low protein groups(P＜0.05).3)The primary egg weight in medium ME group was significantly higher than that in high ME group(P＜0.05);the ovarian index in high protein group was significantly higher than that in low and medium protein groups(P＜0.05).4)The relative abundances of Firmicutes and Lactobacillus in cecum in medium ME group and high protein group was high,while the Proteobacteria relative abundance in cecum was low.Considering all indices comprehensively,it is recommended that the optimal dietary ME and CP levels for Xueshan breeding hens during growing period are 11.30 MJ/kg and 15.50％,respectively.[Chinese Journal of Animal Nutrition,2024,36(6):3642-3656]
万方数据
维普
