| In this experiment,the aim of this study was to evaluate the effects of fiber level on growth performance,slaughter performance,blood biochemical parameters,apparent utilization of nutrients,gastrointestinal tract development,enzyme activity,gastrointestinal tract p H and microflora using corn straw fiber source in different growth stages of Zi geese.At the end of 4 weeks,the same batch of no significant difference in body weight in weight between of 288(male and female)healthy Zi geese were used in a complete randomized design with dietary fiber level and growth period as the experimental factors.They were randomly divided into 4 groups with 3 replicates in each group,and each replicate consisted of 24 Zi geese.The test for the 4 levels of dietary fiber,the theory of crude fiber levels were 4.00%,7.00%,10.00% and 13.00%.The whole period of the experiment was 5~13 weeks for the Zi geese.Body weight and daily feed intake were measured weekly throughout the experimental period.The Zi geese were slaughtered at 5,9 and 13 weeks of age,and the gastrointestinal flora,enzyme activity,gastrointestinal development,nutrient apparent metabolic rate,slaughter performance and blood biochemical parameters were sampled and determined.The results were as follows:(1)Dietary fiber level had no significant effect on daily feed intake and feed weight ratio(P>0.05),but there was an increasing trend in daily gain(P=0.0517).The daily gain of 13.00% dietary fiber was higher than that of the 4.00% dietary fiber at 10~13 weeks of age(P<0.05).Growth period had a significant effect on daily gain and feed weight ratio(P<0.05),but there was no significant effect on growth period(P>0.05).With the increase of age,the daily gain of each treatment group decreased gradually,and the material weight ratio increased gradually.(2)The apparent utilization rate of CF,NDF,ADF,HC,CP,Ca and P was affected by dietary fiber level and growth period(P<0.05).At 5 weeks of age,the apparent utilization of nutrients was highest at the level of 4.00% dietary fiber,and at 9 and 13 weeks of age,the apparent utilization rate of CP and Ca was still the highest at the level of 4.00% dietary fiber,and the apparent utilization rate of other nutrients was the highest at the level of 7.00% dietary fiber(P<0.05).However,with the increase of growth period,the apparent utilization rate of nutrients increased(P<0.05).(3)The relative weight of gizzard,stomach,duodenum,jejunum and ileum was the highest at 13.00% of dietary fiber level,and the length of jejunum and cecum length were the longest,and the relative weight of the gland was the highest at the level of dietary fiber of 4.00%(P<0.05).The VH of duodenum and cecum was the longest in 13.00% of dietary fiber,and the VW of duodenum and cecum was the widest in the dietary fiber of 13.00%,and the VCR of jejunum and caecum and the VSA of duodenum and ileum were the highest in 13.00% of dietary fiber(P<0.05).The CD of the cecum was the lowest in the 13.00% dietary fiber level(P<0.05).Dietary fiber level had an effect trend on VCR of duodenum(P =0.0652)in 13.00% of dietary fiber.The relative weight of the gastrointestinal tract,the length of the jejunum and cecum,the VH,VW,VCR and VSA of the duodenum and ileum,the VH,CD and villus surface area,and the VSA of the cecum were significantly affected by the growth period(P<0.05).(4)Under the condition of 13.00% dietary fiber level,the semi eviscerated rate,eviscerated rate and the leg muscle rate of the geese were the highest(P<0.05),while the dietary fiber level had no significant effect on the carcass rate and pectoral muscle ratio(P>0.05).The growth period has a significant impact on the slaughter performance(P<0.05),wherein the carcass rate and leg muscle rate decreased with the growth period of growth(P<0.05),semi eviscerated rate,eviscerated rate and breast muscle rate increased with increasing growth period(P<0.05).(5)The concentrations of BUN,TC and TG in the blood of the Zis were the highest in the 4.00% dietary fiber levels,and the lowest in the 13% dietary fiber(P<0.05),but they decreased with the growth period(P<0.05).The concentrations of GLU,TP and ALB were not affected by dietary fiber level and growth period(P>0.05).(6)Dietary fiber levels had no significant effect on p H in gastrointestinal tract(stomach,stomach,duodenum,jejunum,ileum,cecum and rectum)(P>0.05).The p H of the 13 week old cecum was significantly higher than that of the 5 and the 9 week old,and the p H of the ileum in the 5 and the 9 week old was significantly higher than that at the age of 13 weeks(P<0.05).The activity of carboxymethyl cellulose in addition to the ileum was affected by dietary fiber levels(P<0.05),not affected by the time of growth(P>0.05).The activities of avicelase,carboxymethyl cellulose,glycosidase and xylanase in the gizzard,duodenum,jejunum and caecum were affected by dietary fiber levels and growth periods(P<0.05).All parts of the gastrointestinal avicelase,carboxymethyl cellulose,glycosidase and xylanase activity increased with dietary fiber levels and growth period(P<0.05),the lowest activity in 4.00% levels of dietary fiber by enzyme,the 13.00% highest level of fiber(P< 0.05).(7)There are 25 phyla and 298 genera in the gastrointestinal tract of Zi goose,Firmicutes,Proteobacteria and Bacteroidetes are the main pathogens.The structures of the bacteria in the gizzard,ileum and caecum were different,and the ability of the bacteria in the cecum to carbohydrate metabolism was higher than that of the muscle stomach and ileum.Dietary fiber level affected the structure of cecal flora.At 13 weeks of age,with the increase of fiber level,the ability of bacteria to enhance the carbon metabolism was increased.To sum up,dietary fiber level had a significant effect on daily gain,apparent utilization rate of nutrients,gastrointestinal development,emi eviscerated rate,eviscerated rate and the leg muscle rate,the concentrations of BUN,TC and TG in the blood,enzyme of cellulase activity and gastrointestinal bacteria of Zi geese,but had no effect on the feed intake and feed weight ratio,p H of gastrointestinal tract.The level of dietary fiber suitable for the feeding of geese at 5~9 weeks was 7.00%,and at 10~13 weeks was10.00%. |
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