摘要
本试验旨在研究低蛋白质饲粮补加过瘤胃赖氨酸(RPLys)对多浪羊生长性能、养分表观消化率、瘤胃发酵参数及氮代谢的影响.将9只体况相近且安装永久性瘘管的多浪羊羯羊,采用3×3拉丁方设计,随机分为3组:CK组(饲喂14％蛋白质水平的饲粮)、DP组(饲喂12％蛋白质水平的饲粮)、LP组(饲喂12％蛋白质水平饲粮+14.0 g/d RPLys).试验分3期进行,每期28 d,其中预试期15 d,正试期13 d.结果表明:1)各组间的初重及干物质采食量(DMI)无显著差异(P＞0.05),LP组的平均日增重(ADG)极显著高于CK组和DP组(P＜0.01),CK组和DP组的ADG差异不显著(P＞0.05),LP组的料重比(F/G)显著低于CK组和DP组(P＜0.05),CK组和DP组的F/G差异不显著(P＞0.05).2)各组间干物质(DM)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)和粗脂肪(EE)表观消化率差异不显著(P＞0.05);LP组粗蛋白质(CP)表观消化率极显著高于CK组和DP组(P＜0.01),CK组CP表观消化率极显著高于DP组(P＜0.01);LP组有机物(OM)表观消化率极显著高于CK组和DP组(P＜0.01),CK组和DP组OM表观消化率差异不显著(P＞0.05).3)低蛋白质饲粮补加RPLys对多浪羊瘤胃氨态氮(NH3-N)、丁酸(BA)和戊酸(VA)含量无显著影响(P＞0.05);DP组和LP组微生物蛋白(MCP)含量极显著高于CK组(P＜0.01);LP组乙酸(AA)和丙酸(PA)含量极显著高于CK组和DP组(P＜0.01),CK组和DP组AA和PA含量差异不显著(P＞0.05);CK组乙酸/丙酸极显著高于LP组(P＜0.01);LP组总挥发性脂肪酸(TVFA)含量极显著高于CK组和DP组(P＜0.01),CK组和DP组TVFA含量差异不显著(P＞0.05).4)各组间多浪羊进食氮、尿氮、粪氮、总排出氮、沉积氮、氮利用率和氮生物学价值均差异不显著(P＞0.05),但与CK组相比,DP组与LP组的粪氮有降低的趋势(0.05＜P＜0.10),且DP组与LP组的氮利用率和氮生物学价值分别提高了 6.55％、14.09％和2.58％、11.06％.综上所述,低蛋白质饲粮补加14.0 g/d RPLys能够提高多浪羊的ADG以及CP和OM表观消化率,促进MCP的合成效率,增加挥发性脂肪酸产量,并提高氮利用率和生物学价值.
Abstract
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]
基金项目
国家自然科学基金(32260845)
兵团重大科技项目(2023AB078)
塔里木大学校长基金重大项目培育专项(TDZ-KZD202204)
维普
万方数据