Effects Of The Starch Source On Pellet Processing Characteristics,Production Performance And Cecal Microflora Of Meat Rabbits

The purpose of this experiment was to study the effects of the starch source on pellet processing characteristics,production performance,nutrient digestibility,intestinal digestive enzyme activity and cecal microflora of meat rabbits.A single factor fully randomized experimental design was adopted.Ninety-six weaned meat rabbits with good health and average body weight of 104.17 g were randomly divided into four groups,each group contained four replicates of six rabbits and reared in a single cage.Rabbits in each group were fed 6% different sources(corn starch,wheat starch,potato starch and pea starch)of starch diet.(The composition and proportion of raw materials are the same.).The pre-test period was 5days and the trial period was 40 days.At the end of feeding experiment,the digestion test was carried out by endogenous indicator method.After that,heart blood was collected and serum was separated.Rabbits were slaughtered and the contents of stomach,duodenum,jejunum,ileum and cecum were taken and a variety of indexes were determined.The test results showed as follows.(1)Processing characteristics of feed pellet.The hardness of pellet feed in potato starch group was the highest and the powder content was the lowest,which were contrary to that of wheat starch group.The percent fines of pea starch group was significantly higher than that of corn starch and potato starch group(P<0.01),and significantly higher than that of wheat starch feed(P<0.05).The pellet bulk density of corn starch and potato starch group was significantly higher than that of pea starch group(P<0.01),and they were higher than that of pea starch for 5.90% and 4.27%,respectively.The pellet bulk density of wheat starch diet was significantly higher than that of pea starch diet(P<0.05).Therefore,the order of superiority and inferiority was potato starch > corn starch > wheat starch > pea starch.(2)Production performance.Corn starch diet significantly increased the average daily gain(ADG)of meat rabbits(P<0.05),and decreased the feed-gain ratio(F/G).The mortality elimination rate and F/G of meat rabbits in pea starch group were the highest.The average daily feed intake(ADFI)of meat rabbits in potato starch group was significantly higher than that in wheat starch and pea starch group(P<0.05),but there was no significant differencewith corn starch group(P>0.05).The order of superiority and inferiority was corn starch >wheat starch > potato starch > pea starch.(3)The nutrient digestibility and intestinal digestive enzyme activity.The rate of nutrient digestibility and energy utilization of meat rabbits in corn starch and wheat starch groups were higher than those meat rabbits in potato starch and pea starch.The amylase activity of empty ileum in meat rabbits was significantly increased in potato starch group(P<0.05),moreover,the amylase activity of duodenum was also the highest.The cellulase activity of cecum in meat rabbits in pea starch group was the highest.The pepsinase activity of meat rabbits in corn starch group was significantly higher than that in wheat starch group(P<0.05).Potato starch and pea starch diets were benefit for increasing the activity of intestinal digestive enzyme meat rabbits.(4)Blood biochemical indicators.The content of serum total cholesterol of meat rabbits was significantly increased in corn starch and wheat starch groups(P<0.05).The content of serum lactic dehydrogenase of meat rabbits was significantly increased in pea starch group(P<0.05).The content of blood sugar and insulin of meat rabbits were the highest in wheat starch group and the lowest in potato starch group.The content of serum triglyceride was the highest in corn starch group and the lowest in potato starch group.The content of glucagon was the highest in pea starch group and the lowest in corn starch group.(5)Cecal microflora.Pea starch significantly increased the contents of butyric acid(P<0.01),acetic acid and propionic acid(P<0.05)in cecum of meat rabbits.The cecal acetic acid and propionic acid contents in potato starch group were significantly higher than those in corn starch group(P<0.05),while butyric acid content was significantly higher than that in corn starch group and wheat starch group(P<0.05).Potato starch and pea starch significantly increased the ccal volatile fatty acids and lactic acid contents of meat rabbits(P<0.05).The similarity of cecal microflora of meat rabbits among groups was very low,and there was no obvious clustering rule.The starch source had no significant effects on abundance and diversity of cecal microflora and proportion of dominant microflora in meat rabbits(P>0.05).The dominant bacteria of meat rabbits were Firmicutes(64.99%),Bacteroidetes(18.18%),Verrucomicrobia(10.30%),etc.Pea starch and potato starch significantly decreased the number of Escherichia coli in cecum of meat rabbits(P<0.05),and pea starch significantly increased the number of Lactobacillus in cecum of meat rabbits(P<0.05).In summary,in the experimental condition,potato starch was benefit for improving the pellet processing characteristics,corn starch and wheat starch had better influences on the production performance and nutrient digestibilty of meat rabbits.The starch source affected the fermentation parameters of the cecal microflora and the number of main microflora,but had no significant effect on the microbial structure.The order of superiority and inferiority was corn starch > wheat starch > potato starch > pea starch.