Effects Of Rosemary Extract On Growth Performance And Meat Quality Of Broilers

This experiment was conducted to investigate the effects of rosemary extract on growth performance,slaughter performance,meat quality,antioxidant capacity and immune level of broilers,and to find the appropriate supplemental level of Rosemary extract in broiler diet,so as to provide scientific basis for better utilization of Rosemary extract.A single-factor randomized block design was used in this experiment,and 560 one-day-old AA broilers were randomly divided into 5 treatments with 14 replicates per treatment and 8 broilers per replicate.The control group was fed a basal diet without rosemary extract,and the 4experimental groups were fed the basal diet with rosemary extract 250,500,750 and 1000mg/kg,respectively.The experiment lasted for 42 days and was divided into 2 stages of 1 to21 days of age and 22 to 42 days of age.At the end of the experiment,one chicken with an average body weight was selected from each replicate for blood sampling and slaughter,and growth performance,slaughter performance,meat quality,serum biochemical indices,immune indices and antioxidant indices were analyzed.The results were as follows:1、Rosemary extract had a tendency to increase ADG(P=0.058)and significantly reduce F/G(P<0.05)in the early period(1 to 21 days)of broilers,and the supplementation of 500mg/kg rosemary extract had the best effect.However,there were no significant differences in the indexes of broilers in the later stage(22-42d)and the whole experiment(P>0.05).2、There were no significant differences in half-eviscerated percentage,eviscerated percentage,percentage of breast muscle,percentage of leg muscle and percentage of abdominal fat(P>0.05),and no significant differences in relative length and weight of duodenum,jejunum and ileum(P>0.05).3、Rosemary extract significantly reduced the cooking loss of breast muscle and leg muscle of broilers(P<0.05),and the leg muscle shear force tended to decrease(P=0.09).4、Rosemary extract had significant effects on serum Glu,TP,ALB,UA,TC,TG,HDL-C and LDL-C levels of broilers(P<0.01).5、The levels of T-AOC,GSH-Px,SOD and CAT in serum and liver of broilers were significantly affected by rosemary extract(P<0.01).The levels of t-aoc,gsh-px,SOD and CAT in serum of broilers were the highest and the levels of MDA were the lowest when rosemary extract was added 500mg/kg.6、The levels of IL-2,IgM,IgG and IgA in serum and liver of broilers were significantly affected by rosemary extract(P<0.01),and the immune indexes of broilers were the best when rosemary extract was added 500mg/kg and 750mg/kg.Taking growth performance,slaughter performance,meat quality,serum biochemical indices,immune function and antioxidant capacity into consideration,the supplementation of500mg/kg rosemary extract had certain effects on growth performance and meat quality of broilers,and could also improve immune function and antioxidant capacity of broilers.