The Effect Of HMBi On Growth Performance Of Fujian Yellow Rabbit

Purpose:This test was conducted to determine the effect of different HMBi levels on intestinal enzyme activity, immunity performance and cecum flora of Fujian yellow rabbits.which would provide theoretical basis for applications of spent HMBi as Feed additives in Fujian yellow rabbits feed.Method:In this study, two hundred weaned Fujian yellow rabbits(similar SW) of 35 ± 2 days were randomly divided into 4 groups with 5 repeats, and each replicate 10 Fujian yellow rabbits. The control group (CK)was fed the basal diet;Group Ⅰ, Ⅱ and Ⅲ were fed the basal diets supplemented with 0.20%,0.40% and 0.60% HMBi,respectively.Pre-feeding period was 7 days and the experiment was lasted for 52 days. Growth and slaughter performance, immune organ index, serum biochemical criterion, small intestinal digestive enzyme activity, cecal microflora and intestinal morphology, muscle amino acids content in the four groups were compared and analyzed.Results1. The growth and slaughter performance:HMBi levels could improve average daily gain(ADG) and average daily intake (ADI)(P<0.05), when the HMBi additional levels was 0.4%, ADG reached the highest and ADI reached the biggest; The feed to gain ratio(F/G) was the minimum which the HMBi additional levels was 0.6%, it was 11.05% lower than the control group.Compared with control group, the carcass weight and slaughter rate in group Ⅱ were significantly and extremely significantly increased (P< 0.05; P< 0.01), the body weight in groups Ⅱ and Ⅲ was significantly increased (P< 0.05).2. Immune organ index:Spleen weight and spleen index of groups Ⅰ, Ⅱ, Ⅲ were higher than those of control group (P> 0.05), Group Ⅰ was close to the control group. Thymus index of Group Ⅱ were higher than those of control group(P<0.01),Liver index of Group Ⅱ and Group Ⅲ were significantly higher than those of control group (P< 0.05).The immune organ weight and immune index reached the maximum,when the HMBi additional level was 0.4%.3. Immunoglobulin:IgA level of group Ⅱ was significantly higher than the control group(P<0.05).IgG level of group Ⅱ was 5.65% higher than the control group.There was no significant effect on IgM(P>0.05).4. Serum biochemical criterion:HMBi levels could improve serum total protein.Group Ⅱ and group Ⅲ were significantly higher than the control group (P< 0.05).The serum cholesterol of group Ⅲ was significantly lower than the control group(P<0.01).There were no significant difference in the albumin,triglycerides ,glucose and urea nitrogen among test groups and control group(P> 0.05).5. Intestinal enzyme activity:Compared with control group, the amylase activity of group Ⅱ and Ⅲ were significantly increased(P< 0.05).The activity of lipase and trypsin were no significant difference among the test groups and control group(P> 0.05).The strongest lipase activity was group Ⅱ,and the lipase activity was 68.10± 7.13U/g·prot.6. The intestinal morphology:Compared with control group.the villous height of duodenum and jejunum in group Ⅱ were extremely significantly increased (P< 0.01),the villous height of jejunum and ileum in group Ⅲ were extremely significantly increased (P< 0.01);The crypt depth of duodenum and jejunum in groups Ⅰ,Ⅱ and Ⅲ were significantly or extremely significantly decreased (P< 0.05;P< 0.01),the crypt depth of ileum in groups Ⅱ and Ⅲ were significantly increased (P< 0.05);Compared with control group,the V/C of duodenum and ileum were significantly increased(P< 0.05),the V/C of jejunum in group Ⅲ was extremely significantly increased (P< 0.01).7. Caecal microflora:HMBi levels could improve lactic acid bacteria and the total number of anaerobic bacteria(P<0.05),meanwhile,HMBi levels had effects on e. coli number and the total number of aerobic bacteria(P<0.05).The group II had the best effectiveness.8. Muscle amino acids content:Compared with the control group,serine, glycine, isoleucine and phenylalanine content had significant difference(P<0.05); Compared with the control group content of aspartic acid, glutamic, methionine and leucine had highly significant difference(P<0.01),group of Ⅲ was highly significantly higher than other groups on methionine content(P<0.01); Associated with the taste of muscle like serine, glutamic acid, glycine, leucine and isoleucine levels were increased with the increment of HMBi added.Conclusion1. Dietary HMBi Supplementation had significant influence on growth and slaughter performance of Fujian yellow rabbits.2. Dietary HMBi Supplementation could improve serum biochemical criterion of Fujian yellow rabbits, raise immune function and small intestinal digestive enzyme activity, maintain the cecum micro ecological balance and the intestinal morphology structure, improve the quality of the rabbit meat.3. The appropriate HMBi level in the diet of Fujian yellow rabbit was 0.40%, could maintain the best balance of intestinal flora, and improve the production performance and digestive enzyme activity, rabbit meat good flavor and quality.