Effects Of Diets Supplemented With Essential Oil Eutectic On Grow Performance,Intestinal Health,Antioxidant Capacity,and Immune Function In Meat Poultry

The objective of this thesis was conducted to investigate the effect of different dosage of thymol and carvacrol eutectic supplementation in the diets on the grow performance,intestinal health,antioxidant capacity,and immune function in meat ducks and broiler chickens.This study includes two experiments.Experiment 1:Effects of diets supplemented with essential oil eutectic on Growth Performance,Intestinal Morphology,Digestive Enzyme activity,and Antioxidant Capacity in meat ducksA total of 480 1-day-old cherry valley ducks with similar body weight were randomly divided into 5 groups(6 replicates/group,16 ducks/replicate).The ducks in control group and 4 experimental groups were fed essential oil eutectic(EOE)0,15,30,60 or 120mg/kg,respectively.The EOE is a 1:1 eutectic of thymol and carvacrol,and its effective content is 50%.The experiment lasted for 35 days,feed and water were provided ad libitum.The experiment is divided into the early stage(1-14 days)and the later stage(15-35 days).The results showed that: 1)There were no significant differences in the growth performance and the contents of total bacteria,Salmonella and Escherichia coli in cecal digesta among all groups(P > 0.05);but with increasing of dietary EOE levels,the mortality rate was linearly decreased in the early stage(P < 0.05).2)Compared with the control group,at 14 days of age,diets supplemented with 60 and 120 mg/kg EOE significantly increased the villus heigh;at 35 days of age,diet supplemented with 30mg/kg EOE significantly increased the jejunal villus height and villus to crypt ratio(P <0.05).3)Compared with the control group,adding 120 mg/kg EOE significantly increased jejunum amylase activity of ducks at 35 days of age(P < 0.05).4)Compared with the control group,diets supplemented with 60 and 120 mg/kg EOE significantly increased the content of MDA in ileum mucosa at 35 days of age(P < 0.05);but MPO activity in ileum mucosa in 30 and 120 mg/kg EOE groups was significantly increased(P < 0.05).These results suggest that the effects of EOE are dose-dependent;it is recommended to add 120mg/kg EOE for meat ducks based on the growth performance,digestive enzyme activity,and antioxidant capacity.Experiment 2:Effects of diets supplemented with essential oil eutectic on Growth Performance,Serum Immunoglobulin Content,Intestinal Health,and Antioxidant Capacity in Broiler ChickensA total of 640 one-day-old Arbor Acres broilers with similar body weight were randomly divided into 4 groups(8 replicates/group,20 broilers/replicate).Birds in the 4experimental groups were fed a basal diet with EOE at 0,30,60 or 120 mg/kg,respectively.The EOE is the same with Exp.1.The experiment lasted for 42 days,feed and water were provided ad libitum.The experiment is divided into the early stage(1–21 days)and the later stage(22-42 days).The results showed that: 1)The growth performance of birds during 22-42 d or 1-42 d of age,jejunal and ileal morphology,and ileal MUC2,OCLN and IL-10 m RNA expression at 42 d of age linearly or quadratically increased(P < 0.05)and the ileal IL-6 m RNA expression quadratically decreased(P < 0.05)with increasing of dietary EOE levels;Meanwhile,compared with the other 3 groups,birds fed diet with 30mg/kg EOE presented better growth performance,intestinal morphology and function.2)Compared with the control group,supplemented 60 mg/kg EOE significantly increased serum MDA and T-AOC content,as well as the ileal mucosal MDA content of broilers at21 days of age(P<0.05).However,supplemented 120 mg/kg EOE significantly increased serum GSH and T-AOC,as well as the ileal mucosal MDA content(d 21)and SOD activities(d 42)and T-AOC in breast muscle(d 42)(P < 0.05).Meanwhile,the contents of serum MDA,GSH,and T-AOC(21 d)and ileal mucosa T-AOC and SOD(42 d)and breast muscle T-AOC linearly or quadratically decreased with increasing of dietary EOE levels(P < 0.05).3)Compared with the control group,the addition of 30 mg/kg EOE significantly increased the total bacteria content in cecal digesta of 42-day-old broilers(P <0.05).It is recommended to add 30 mg/kg EOE for broilers based on growth performance,intestinal morphology,and antioxidant capacity.In conclusion,supplemented EOE to the diets could enhance the growth performance,the intestinal villus height,and villus to crypt ratio and improve the intestinal morphology and then regulate the antioxidant capacity in meat ducks and broiler chickens.The effect of EOE is dose dependent.At last,the appropriate amount of EOE addition could be recommended based on different biological indicators.