| In this study,the effects of different levels of bile acid salt added to the diet of yellow feather broilers on the growth performance,organ index,serum indicators,nutrient transporters and digestive enzyme genes in the liver and intestines of yellow feather broilers were studied,and the reasonable bile acid salt addition levels that can improve the growth performance,immune ability,regulate intestinal health and reduce the incidence of diseases of Qinghai yellow feather broilers were explored.420 healthy1-day-old yellow feather broilers hatched in the same batch were selected as the experimental animals.420 chickens were divided into 7 groups(4 replicates in each group)with 15 chickens in each replicate.The first group was the control group,and the second group was the antibiotic group.0.02% tylosin was used to replace the bran in the basic diet.The third group,the fourth group,the fifth group,the sixth group and the seventh group were added with 0.015%,0.025%,0.035%,0.045% and 0.055% bile acid to replace the bran in the basic diet.The feeding experiment was conducted for 28 days.The results showed that 0.015% bile acid salt could increase the body weight and daily gain of yellow feather broilers for 7 days(P<0.05),and 0.045% bile acid salt could increase the body weight and daily gain of yellow feather broilers for 28 days(P<0.05);0.035% bile acid salt reduced the feed weight ratio of 7-day yellow feather broilers(P<0.05),and 0.045% bile acid salt reduced the feed weight ratio of 28 day yellow feather broilers(P<0.05).To sum up,0.045% bile acid salt can promote the growth of Broilers and improve their growth performance.In terms of organ index,0.025% bile salt can improve the liver index of 7-day yellow-feather broiler(P<0.05),and 0.045% bile acid can improve the liver index of28-day yellow-feather broiler(P<0.05);0.045% bile acid Salt increased the thymus index of yellow-feather broilers on 21 d and 28 d(P<0.05);0.015%,0.035%,0.045%and 0.055% bile salts increased the bursa index of yellow-feather broilers on 14 d(P<0.05),0.045% bile salt could increase the bursa index of 21-day yellow-feathered broilers(P<0.05).From the above indicators,it is concluded that adding 0.045% bile salt can promote the growth of immune organs of yellow feather broilers,enhance the immunity of animals,and improve the disease resistance of animals.In terms of serum biochemical indicators,0.025% bile salt decreased serum total cholesterol and low-density lipoprotein,and increased the content of high-density lipoprotein;0.035% bile salt significantly reduced serum triglyceride,glucose and growth hormone,and increased glucagon levels;0.045% bile salts significantly decreased serum insulin and cortisol,and increased immunoglobulin Ig A and Ig M levels.Based on the above indicators,it was concluded that adding 0.035% and 0.45%bile salts can effectively improve the serum biochemical indicators of yellow feather broilers and enhance the immunity of chicks.In terms of gene expression,the results showed that:(1)The expression levels of SREBF1,FATP4,ApoB,FAS and ACC mRNA in different parts of broilers were significantly different(P<0.05).The expression level of SREBF1 mRNA was the highest in the ileum,followed by the jejunum,and then Liver and duodenum were the lowest;FATP4 mRNA expression was highest in duodenum,jejunum and liver,and lowest in ileum;ApoB mRNA expression was highest in ileum,followed by duodenum and jejunum,and lowest in liver;FAS mRNA expression The amount of ACC mRNA was the highest in the duodenum,jejunum and ileum,and the lowest in the liver;the expression of ACC mRNA was highest in the liver,followed by the duodenum and ileum,and the lowest in the jejunum.(2)There were significant differences in the expression of SREBF1,FATP4,ApoB,FAS and ACC mRNA in broilers at different days of age(P<0.05).The expression of SREBF1 mRNA decreased first and then increased with the increase of days of age,the highest at 7 and 28 days of age,the second at 14 days of age,and the lowest at 21 days of age;The expression of FATP4 mRNA decreased gradually with the increase of age,with the highest at 7 days,followed by 14 days,followed by 21 days,and the lowest at 28 days;The expression of ApoB mRNA decreased with the increase of age,the highest at 7 and 14 days,the second at 21 days,and the lowest at 28 days;FAS mRNA expression was the highest at 14 and 28 days of age,followed by 7 days of age and the lowest at 21 days of age;The expression of ACC mRNA increased with the age of 28 days,followed by 7,14 and 21 days.(3)There were significant differences in the expression of SREBF1,FATP4,ApoB,FAS and ACC mRNA among different bile salts(P<0.05),and 0.045% bile acid decreased the expression of SREBF1,FATP4,ApoB,FAS and ACC mRNA(P<0.05).From the above indicators,it can be concluded that adding 0.045% bile acid can regulate the expression of genes related to fat metabolism to promote fat catabolism,which plays a key role in improving fat deposition in broilers.Based on the analysis of the above indexes,it is suggested that 0.045% bile acid salt is the most suitable in the diet of yellow feather broilers. |
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