Effects Of Lonicera Japonica Extract On Growth Performance,Antioxidant And Immune Function Of Broilers

Under the background of comprehensive ban on antibiotics in feed,plant extracts are widely used as green additives in livestock and poultry production.Lonicera japonica is a traditional Chinese medicine plant in my country with strong vitality and wide distribution.At present,Lonicera japonica extracts are mainly used in traditional Chinese medicine treatment and health care.There were relatively few studies on livestock and poultry production,especially on the effects of broiler growth.Therefore,this experiment took Hubbard broilers as the research object to investigate the effects of dietary supplementation with different levels of Lonicera japonica extract（LJE）on growth performance,slaughter performance,immune organ indexes,meat quality,serum antioxidant and biochemical indexes,and intestinal morphology,in order to provide technical guidance and theoretical basis for the application of LJE in the broiler industry.A total of 720 healthy 1-day-old Hubbard broilers with similar body weight were randomly divided into 4 treatment groups with 6 replicates per treatment and 30 broilers per replicate using a single-factor experimental design.The control group was fed a basal diet,and the experimental groups were fed the basal diet supplemented with 125 mg/kg LJE（LJE125 group）,250 mg/kg LJE（LJE 250 group）and 500 mg/kg LJE（LJE 500 group）,respectively.The experiment lasted for 42 days.The results show that:（1）From 1 to 21 days of age,compared with the control group,adding different levels of LJE significantly increased the average daily gain（ADG）and body weight at 21 days of age of broilers（P<0.01）,and significantly decreased the ratio of feed to gain（P<0.01）,but there was no significant difference among three groups（P>0.05）.Average daily feed intake（ADFI）and mortality were not affected by different LJE supplemental levels（P>0.05）.From22 to 43 days of age,compared with the control group,dietary LJE supplementation at different levels significantly increased ADG and body weight of broilers at 43 days of age（P<0.01）,and significantly decreased the ratio of feed to gain（P<0.01）,but there was no significant difference among three groups（P>0.05）.Dietary supplementation of different levels of LJE significantly increased ADFI of broilers（P<0.01）,and LJE 500 group significantly increased ADFI by 4.31%compared with LJE 250 group（P<0.05）,but there was no significant difference between LJE 125 group and LJE 500 group（P>0.05）.During the whole experiment period（1-43 days of age）,compared with the control group,dietary LJE supplementation at different levels significantly increased ADG（P<0.01）and significantly decreased the ratio of feed to gain（P<0.01）,but there was no significant difference among three groups（P>0.05）.Dietary supplementation of LJE at different levels significantly increased ADFI of broilers（P<0.01）,and LJE 500 group significantly increased ADFI by 3.21%compared with LJE 250 group（P<0.05）,but there was no significant difference compared with LJE 125 group（P>0.05）,and different LJE supplemental levels had no effect on mortality（P>0.05）.（2）The eviscerated yield percentage of broilers in LJE 250 and LJE 500 groups was significantly higher than that in control group（P<0.05）,and increased by 3.05%and 3.30%,respectively,while there was no significant difference among three groups（P>0.05）.LJE supplementation had no significant effects on dressing percentage,half-eviscerated yield percentage,chest muscle percentage,leg muscle percentage and abdominal fat percentage（P>0.05）.（3）Compared with the control group,thymus index of broilers in LJE 125 group was increased by 62.50%,the difference was significant（P<0.05）,but there was no significant difference among three groups（P>0.05）.LJE supplementation had no significant effects on spleen index and bursa of Fabricius index（P>0.05）.（4）Compared with control group,LJE 125 group and LJE 250 group,p H_45minof breast muscle in LJE 500 group was significantly increased（P<0.05）,and increased by 3.53%,6.18%and 3.99%,respectively.LJE supplementation had no significant effects on other indexes of chest muscle and leg muscle quality（P>0.05）.（5）The serum total superoxide dismutase activity in LJE 125 group was significantly increased by 23.73%compared with that in control group（P<0.05）,and the serum total superoxide dismutase activity in LJE 250 and LJE 500 groups was significantly higher than that in control group（P<0.01）.Compared with LJE 125 group,LJE 250 group was significantly increased by 22.17%（P<0.05）,and there was no significant difference between LJE 250 group and LJE 500 group（P>0.05）.The serum glutathione peroxidase activity of three experimental groups was significantly higher than that of control group（P<0.01）,and LJE 500 group was significantly higher than LJE 125 and LJE 250 groups（P<0.01）.LJE supplementation had no significant effects on catalase activity,total antioxidant capacity and malondialdehyde content in serum of broilers（P>0.05）.（6）LJE supplementation had no significant effects on serum alanine aminotransferase,total protein and albumin contents（P>0.05）.Serum aspartate aminotransferase content in LJE 125 and LJE 250 groups was significantly increased compared with control group（P<0.05）,and serum aspartate aminotransferase content in LJE 500 group was significantly increased compared with control group（P<0.01）,but there was no significant difference among three groups（P>0.05）.The serum immunoglobulin M content in LJE 125 group was significantly increased compared with control group and LJE 500 group（P<0.05）,but there was no significant difference between LJE 250 group and LJE 125 group（P>0.05）.（7）Compared with the control group,there were no significant differences in villus height and crypt depth of duodenum,jejunum and ileum and the ratio of villus height to crypt depth of duodenum in LJE 125 group（P>0.05）.The ratio of villus height to crypt depth of jejunum and ileum in LJE 125 group was increased by 31.10%and 40.92%,respectively（P<0.05）.In conclusion,dietary LJE supplementation can enhance antioxidant capacity and immune function,improve intestinal morphology and growth performance of broilers.Under the experimental conditions,the appropriate level of LJE in broiler diet is 125 mg/kg.