Study On The Effect Of Several Additives On Production Performance,Anti-oxidation Capacity And The Intestinal Histomorphology Of Dayu Duck

Dayu duck belongs to a fine local meat variety,which is the famous Nanan dry duck production raw material duck in our province.Dayu county belongs to subtropical monsoon climate,summer high temperature,high humidity duration is long,the average temperature is above 28 ?,and Dayu duck suitable growth temperature is 16-22 ?.When the duck environment temperature above 28 ?,the breed will show heat stress syndrome.The purpose of this study was to investigate the effects of dietary supplementation of ?-lipoic acid,bacitracin zinc,plant essential oil(cinnamaldehyde)and ?-aminobutyric acid on growth performance,slaughter performance,antioxidant capacity and intestinal barrier function of heat-stressed ducks,and to provide scientific basis and theoretical support for alleviating heat stress in meat ducks.There were 720 ducks with similar weight and good physique at 21 days old which were selected and divided into 36 groups for 42 days randomly.The experiment was divided into 6 treatments,6 replicates per treatment and 20 replicates per replicate.The processes are as follows:0(control group),100 mg/kg bacitracin zinc(?group),200 mg/kg ?-aminobutyric acid(group),200 mg/kg ??-lipoic acid(?group),200 mg/kg cinnamaldehyde(?group),50 mg/kg ?-aminobutyric acid+100 mg/kg ?-lipoic acid+100 mg/kg cinnamaldehyde(group)were added to the basal ?diet for 42 days.The growth performance,slaughter performance,serum antioxidant capacity and intestinal histomorphology of ducks were determined during the experiment.The results were as follows:1.There was no significant difference in average daily feed intake,final weight and average daily gain of ducks fed with different additives during the whole experiment period(P>0.05).However,compared with the control group,the feed-meat ratio of duck decreased significantly(P<0.05).At the age of 22-42 days,the feed meat ratio of group?and group ?decreased greatest by 9.44% and 9.30% respectively(P<0.05).The ratio of feed to meat in group was the lo? west at 43-63 days of age,which decreased by 11.30%(P<0.05),the difference between the other groups was not significant(P>0.05),but showed a decreasing trend.2.There was no significant difference in slaughter rate,abdominal fat rate,leg muscle rate and total evisceration rate of ducks fed with different additives during the whole experiment period(P>0.05).But compared with the control group,the half evisceration rate and pectoralis muscle rate of group?were significantly increased by 4.13 % and 11.71 %,respectively(P<0.05).3.Compared with the control group,SOD activity in serum of group and ? ?was significantly increased(P<0.05),GSH-Px activity in serum of group and ? ?was significantly increased(P<0.05),and there was no significant difference between the other groups(P>0.05).The T-AOC contents in serum of ducks were significantly increased(P<0.05)and the MDA contents in serum of ducks were significantly decreased(P<0.05)by adding different additives in diet.4.Compared with the control group,group ?,group ?and group ?could significantly increase the intestinal villus length of ducks(P<0.05).But there was no significant difference between the other groups(P>0.05).There was no significant difference in the depth of intestinal crypt between ducks fed with different additives(P>0.05).To sum up,adding different additives in diet can alleviate the effects of heat stress on the growth performance and slaughter performance of ducks.Group ?could better improve the growth performance of ducks,group and group could ? ?better improve the growth performance of ducks.Group ?and group ?could improve the serum antioxidant capacity of ducks.Group ?,group and group ? ?could enhance intestinal barrier function better.The results also showed that ?-aminobutyric acid,?-lipoic acid and cinnamaldehyde could be used in the production of heat-stressed meat ducks.But the optimum proportion of ?-aminobutyric acid,?-lipoic acid and cinnamaldehyde should be further discussed.