| The purpose of this experiment was to investigate the effects of dietary Chitooligosaccharides(COS)on growth performance,nutrient apparent digestibility,blood physiological indexes,immune indexes and cecum microflora of meat rabbits.A total of 300 growing meat rabbits with similar age(35±2),healthy condition and body weight were randomly divided into 6 groups with 5 replicates per group and 10 rabbits per replicate.In a single factor completely randomized design,the experiment was divided into 6 treatment groups,including blank control group and antibiotic control group(20mg/kg polymyxin E),and the 4 chitosaccharides groups were supplemented with 50,100,150 and 200 mg/kg,respectively.The pre-trial period lasted for 7 days,and the trial period lasted for 35 days.The results are as follows:(1)Chito-oligosaccharides of 50,100 and 150mg/kg can effectively improve the average daily gain of meat rabbits;The ratio of feed to gain of 150mg/kg group was the best;The mortality and diarrhea rate of 50mg/kg group were the lowest.Chito-oligosaccharides supplementation had a better effect on slaughter performance,and the carcass weight of meat rabbits at 50 and 150mg/kg was significantly higher than that of the control group.Compared with blank control group,the evisceration rate of meat rabbits in chitosaccharide treatment groups was significantly increased.(2)Dietary chito-oligosaccharides significantly increased the digestibility of dry matter,energy and crude protein of meat rabbits,and the best effect was achieved when the supplemental level was 50mg/kg.Compared with antibiotic group,50mg/kg chito-oligosaccharide group could significantly reduce blood glucose and triglyceride contents,and extremely significantly reduce cholesterol content in meat rabbits.Compared with control group and antibiotic group,the thymus weight of meat rabbits in 50 and 150mg/kg chito-oligosaccharide groups was significantly increased.The serum Ig M content of 100mg/kg chito-oligosaccharide group was the highest.The contents of Ig G and complement C4 in serum of 150mg/kg group were the highest.The serum Ig A content in 200mg/kg group was the highest.(3)Dietary chito-oligosaccharides can enrich the intestinal flora structure,and50mg/kg chito-oligosaccharides group significantly increased the abundance of Proteobacteria,and extremely significantly increased the abundance of Rhodanobacteria.In conclusion,feed add shell oligosaccharide can effectively improve the feeding rabb growth performance,apparent digestibility of feed,can improve the thymus weight,the content of immunoglobulin and complement C4,compared with antibiotics can reduce the content of serum cholesterol,triglycerides,and glucose,enrich the community structure in the cecum,feed add shell oligosaccharides have partly replace antibiotic effect.The optimal supplemental levels of chito-oligosaccharides in diets are 50～100mg/kg. |
