Study On The Application Of Vitamin B12 Fermentation Production By-products To Replace Part Of Soybean Meal In Broiler Production

The aim of the present study was to investigate the effects of replacenment of soybean meal by different levels of VB12 fermentation production by-products on growth performance,nutrient digestibility,activities of digestive enzymes,intestinal morphology,slaughter performance,and carcass quality of broilers.The breeding benefits of using VB12 by-products as raw materials for proteinein feed in the production of broilers were also discussed,which provided a theoretical basis for the rational development and utilization of VB12 by-products in broiler production.This study is consist of four experiments:The objective of Trial 1 was to study the effects of different supplyment levels of VB12 by-products in the diet on performance,organ index and blood biochemical parameters of broilers.A total of 576 healthy 1 day-old Arbor Acres(AA)broilers were randomly divided into 6 groups.Each group consisted of 6 replicates with 16 broilers per replicate.The control group was received the corn-soybean basal diets from 1 to 42 d of age.While,the experimental groups were fed the basal diets containing 1%,3%,5%,7%,and 9%VB12 by-products,respectively.The experiment period is 42dincluding the early stage(1～21 d)and the late stage(22～42 d).The results showed that:(1)From d 1 to d 42s,the average daily feed intake of broilers in experimental groups was significantly lower than that in control group(P<0.05).The supplement of 5%,7%,and 9%VB12 by-products also decreased average daily gain of broilers(P<0.05).(2)There are no significant difference in serum biochemincal indicators of broilers at 42 d of age when the supplement levels of VB12 by-product was less than 7%(P>0.05).The aim of Trial 2 was to valuate the effects of different supplyment levels of VB12 by-products in the diet on nutrient digestibility,activities of digestive enzymes,intestinal morphology and mRNA levels of intestinal nutrient transporters of broilers.This study shared the same details of the experiment design as that of trial 1.The results indicated that:(1)Compared with the control group,the dry matter digestibility and organic matter digestibility of the group treated with 9%VB12 by-product were decreased significantly at 21 days(P<0.05).In addition,reduced digestion of crude proteinein and crude fat at 42 d of age were observed in broilers fed with the diet containing 7%and 9%VB12 by-product(P<0.05).(2)The supplement of 9%VB12 by-product significantly impaired amylase activity in jejunal chyme and pancreas and trypsin activity in jejunal chyme at 21 d of age(P<0.05).The activity of pancreatic lipase and amylase of jejunal chime in the 7%and 9%groups were also significantly decreased at the age of 42 d(P<0.05).(3)Compared with the control group,the broilers in 7%and 9%groups had a lower villus height in jejunum and ileum at the age of 21 d(P<0.05)..The ileal villus height of broliers in 7%and 9%groups presented the same trend(P<0.05).The Trial 3 investigated the effects of different supplement levels of VB12 by-products in the diet on slaughter performance,meat quality and muscle nutrient composition of broilers.The details of experiment design of this study is same as that of Trial 1.The observations showed that:(1)The semi-eviscerated weight rate and the whole net carcass rate of 9%group were significantly lower than that of the control group(P<0.05),while the slaughter rate,abdominal fat rate and thigh muscle rate of broilers were not altered by supplement of VB12 by-products(P>0.05).(2)Dietary supplementation of VB12 by-products also significantly affected the pH,yellowness and drip loss of the breast muscle(P<0.05).The aim of Trial 4 was to analyze the effects of different supplement levels of VB12 by-products in the diet on breeding benefits of broiler production.This study shared the same details of the experiment design as that of trial 1.The results showed as follows:replacement of soybean meal with 1%VB12 by-product in the broiler diet significantly improved the economic benefit of broiler production,and the income of each broiler will increase by ￥ 0.1 at the age of 42 d.In conclusion,the addition of 3%VB12 by-product to the broiler diet could improve the organ index,immune function and meat quality of broiler in actual production,and no negative impact on growth performance slaughter performance and nutrient digestibility of the broiler were ovserved.In contrast,the high supplement of VB12 by-products in broiler diets will reduce the breeding benefits of broilers production.