甜菜粕替代玉米对肉牛生长性能及瘤胃发酵成分的影响

Effects of dietary sugar beet pulp substitute of corn on growth performance,rumen fermentation and nutrient digestibility of beef

文章旨在研究日粮添加不同水平甜菜粕替代玉米对肉牛生长性能、瘤胃发酵能力及营养物质表观消化率的影响。试验选择初始体重为(237.2±24.5)kg的肉牛36头,随机分为4组,每组9头牛,每头牛作为1个重复,试验共进行20周。试验基础日粮以玉米和青贮高粱为主,处理组分别用33%、67%和100%甜菜粕等量替代玉米。结果:试验期间肉牛总增重和日增重随甜菜粕替代水平的升高表现为显著二次曲线效应(P<0.05),料比表现为显著二次曲线降低(P<0.05)。日粮添加甜菜粕显著提高肉牛瘤胃pH(P<0.05),33%甜菜粕替代玉米组瘤胃氨氮含量最高(P<0.05);随着日粮甜菜粕添加水平的升高,总脂肪酸、乙酸、丁酸含量及乙酸与丙酸比值表现为显著线性升高(P<0.05),而丙酸和异丁酸含量表现为显著线性降低(P<0.05)。有机物、粗蛋白质、中性洗涤纤维、酸性洗涤纤维和纤维素摄入量随日粮甜菜粕水平的升高表现为显著二次曲线增加效应(P<0.05),而粗脂肪摄入量表现为显著二次曲线降低效应(P<0.05)。有机物、中性洗涤纤维、纤维素和半纤维素表观消化率随甜菜粕水平的升高表现为显著线性升高(P<0.05)。血清肌酸酐、胆固醇水平随甜菜粕添加水平的升高表现为显著线性降低(P<0.05),而血清尿素氮、甘油三酯、IGF-1、皮质醇和T4含量表现为显著二次曲线升高效应(P<0.05)。结论:在本试验条件下,肉牛日粮用甜菜粕替代玉米可有效提高营养物质的消化率,改善肉牛瘤胃的发酵能力,在不损害动物健康的前提下提高日增重,降低料肉比,其适宜替代水平为67%。

We conducted this trial to evaluate the sugar beet pulp(SBP)replace corn in diet on growth performance, rumen fermentation and nutrient digestibility of beef. Thirty-six beef with the average body weight(237.2±24.5)kg were allotted to 4 groups,each had 9 beef and each one was be a replicate. This trial last 20 w. The control group fed with the cornsorghum silage diets,while the treatment groups fed with the diets using 33%,67% and 100% SBP substitute of corn. Body weight gain and average daily weight gain were quadratically increased(P < 0.05). Further,increasing the SBP amount in the diet quadratically(P < 0.05)decrease of feed conversion ratio. Ruminal pH was linearly increased(P < 0.05)when as SBP replaced the maize in the diet,While,ruminal NH3-Nconcentration was increased(P < 0.05)for the calves fed with 33% SBP. Increasing the level of SBP in the diet,a linear increase in the total short chain fatty acid,acetate and butyrate proportions (P < 0.05),while the propionate proportion was linearly declined,resulting in a linear increase(P < 0.05)in C2 :C3 ratio. The increased levels of SBP in the diet,the daily intakes of organic matter,crude protein,neutral detergent fiber,acid detergent fiber and cellulose were quadratically increased(P < 0.05),while daily intake of crude fat decline quadratically(P < 0.05). Increasing SBP in the diet increased the level of serum creatinine(P < 0.05)and cholesterol(P < 0.05)were linearly declined as the dietary level of SBP increased,and quadratic increases in the mean blood urea nitrogen,triglycerides,IGF-1, cortisol and T4 concentrations(P < 0.05). In conclusion,sugar beet pulp used in this study as a sole source of energy that can effectively enhance nutrients digestibility and create sufficient changes in ruminal fermentability to increase daily gain and decrease feed conversion without impairing animal health. Under the current results,replacement of up to 67% SBP could be available.