Effects of Low Protein Diet Supplemented with Rumen Protected Lysine on Growth Performance,Nutrient Apparent Digestibility,Rumen Fermentation Parameters and Nitrogen Metabolism of Duolang Sheep
This experiment was conducted to study the effects of low protein diet supplemented with rumen pro-tected lysine(RPLys)on growth performance,nutrient apparent digestibility,rumen fermentation parameters and nitrogen metabolism of Duolang sheep.Nine Duolang wethers with similar body conditions and permanent fistulas were randomly divided into three groups using a 3 × 3 Latin square design:CK group(fed a diet with 14％protein level),DP group(fed a diet with 12％protein level),LP group(fed a diet with 12％protein level+14.0 g/d RPLys).The experiment was divided into 3 periods,each period of 28 days,including 15 days of pre-test period and 13 days of trial period.The results showed as follows:1)there was no significant difference in initial body weight and dry matter intake(DMI)among groups(P＞0.05).The average daily gain(ADG)of LP group was significantly higher than that of CK group and DP group(P＜0.01),and there was no significant difference in ADG between CK group and DP group(P＞0.05).The feed/gain(F/G)of LP group was significantly lower than that of CK group and DP group(P＜0.05),and there was no significant difference in F/G between CK group and DP group(P＞0.05).2)There was no significant difference in ap-parent digestibility of dry matter(DM),neutral detergent fiber(NDF),acid detergent fiber(ADF)and crude fat(EE)among the groups(P＞0.05).The apparent digestibility of CP of LP group was significantly higher than that of CK group and DP group(P＜0.01),and the apparent digestibility of CP of CK group was significantly higher than that of DP group(P＜0.01).The apparent digestibility of OM of LP group was signifi-cantly higher than that of CK group and DP group(P＜0.01),but there was no significant difference between CK group and DP group(P＞0.05).3)Low protein diet supplemented with RPLys had no significant effect on rumen ammoniacal nitrogen(NH3-N),butyric acid(BA)and valeric acid(VA)contents of Duolang sheep(P＞0.05);the content of microbial protein(MCP)of DP and LP groups was significantly higher than that of CK group(P＜0.01).The contents of acetic acid(AA)and propionic acid(PA)of LP group were signifi-cantly higher than those of CK and DP groups(P＜0.01),and there was no significant difference in the con-tents of AA and PA between CK and DP groups(P＞0.05).The ratio of acetic acid/propionic acid of CK group was significantly higher than that of LP group(P＜0.01).The content of total volatile fatty acids(TV-FA)of LP group was significantly higher than that of CK group and DP group(P＜0.01),and there was no significant difference between CK group and DP group(P＞0.05).4)There was no significant difference in nitrogen intake,urine nitrogen,fecal nitrogen,total nitrogen excretion,deposited nitrogen,nitrogen utilization rate and nitrogen biological value of Duolang sheep among all groups(P＞0.05).However,compared with CK group,the fecal nitrogen of DP group and LP group tended to decrease(0.05＜P＜0.10),and the nitrogen utilization rate and nitrogen biological value of DP group and LP group increased by 6.55％,14.09％and 2.58％,11.06％,respectively.In summary,supplementation of 14.0 g/d RPLys in low protein diets can im-prove the ADG,the apparent digestibility of CP and OM,promote the synthesis efficiency of MCP,increase VFA production,and improve nitrogen utilization and biological value of Duolang sheep.[Chinese Journal of Animal Nutrition,2024,36(3):1756-1768]
low protein dietrumen protected lysineapparent digestibilityrumen fermentationnitrogen metabolism
万方数据
维普
