| Plant sterol has the effect of reducing plasma cholesterol content,antioxidant stress,promoting growth,anticancer and so on.Among them,phytosterol as growth-promoting additive has been widely used in livestock and poultry breeding production.However,there are still few studies on anti-heat stress.The aim of this study was to investigate the effects of phytosterol on the production performance,slaughter performance,proportion of immune organs,serum physiological and biochemical indexes and antioxidant performance of yellow broiler under high temperature.In this trial,60026-day-old healthy ephedra hens were randomly divided into 5 groups with 3 replicates per group and 40 replicates per group,The trial period was 30 days.Group A was the blank control group fed basic diet,while group B,C,D and E were supplemented with additional5% plant sterol of 100 g/t,200 g/t,300 g/t and 400 g/t,respectively,in addition to the basic diet.The ambient temperature is controlled at 33℃±1℃,and the humidity is more than70%±10%.After fasting for 12 h at the age of 55 days,a chicken with a similar average weight was randomly selected for slaughter for each repetition.Abdominal fat,bursa of fabricius,spleen,pectoralis and thigh muscles were weighed,and the serum from the chicken neck was separated and stored for testing.The blood routine index was examined to determine the serum fat metabolism index and antioxidant index.The middle jejunum was sectionized and the thickness of the intestinal mucosa,the height of the villi and the depth of the crypt were measured.The results are as follows:(1)Different levels of phytosterols were added to the diet to improve the end weight,daily weight gain,feed intake and feed ratio of rhubarb feathered chicken with heat stress,among them,300 g / T group was significantly better than the control group in terms of food intake,daily gain and survival rate(P<0.05).(2)There was no difference in slaughter rate,half bore rate,full bore rate,chest muscle rate,leg muscle rate.Abdominal fat rate decreased;(3)Compared with the control group,the bursa index and spleen rate index of each experimental group were increased,but the difference was not reached(P>0.05).(4)There was no difference in Blood Routine Indexes between the experimental group and the control group(P>0.05).Cholesterol and LDL cholesterol decreased to a certain extent,and the content of cholesterol in serum was negatively correlated with the amount of phytosterol added;the content of alkaline phosphatase in serum increased,but each index did not reach a significant difference(P>0.05);(5)the content of superoxide dismutase in each experimental group was higher than that in the control group,and the content of malondialdehyde was lower than that in the control group,but it did not reach a significant level There were significant differences(P>0.05);glutathione peroxidase content in 200g/t-400g/t groups was significantly higher than that in the control group(P<0.05);6)the height of jejunal villi in each experimental group was higher than that in the control group,and the depth of jejunal villi and V/C in 200g/t group were significantly higher than that in the control group(P<0.05);The depth of jejunal crypt in 200g/t group was significantly better than that in the control group(P<0.05).To sum up: adding different levels of phytosterol in the diet can improve the growth performance of the yellow feather broilers under high temperatur.Phytosterol can alleviate the damage of heat stress on the yellow feather broilers by improving the antioxidant capacity of the body and maintaining the intestinal morphology.In the whole experimental period,the daily gain,feed intake,survival rate,serum antioxidant index and jejunum morphology and structure of yellow feather broiler which in 300g/t group were the best among the four different dosages of phytosterol at high temperature.Generally speaking,the effect of using 300g/t phytosterol in the diet of Lingnan Yellow Feather Broiler is relatively good. |
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