| Objective: Bitter almonds are good traditional Chinese medicine,and the main component of bitter almond for therapeutic effect is amygdalin.Amygdalin has a variety of biological activities of good antitussive and antiasthmatic effects,as well as anti-inflammatory,anti-tumor and immunoregulation biological functions.At present,there are few studies on the effects of amygdalin(cyanogenic glycoside)on the growth performance and meat quality of AA broilers.This experiment was conduct to investigate the effects of different doses of cyanogenic glycoside in bitter almond powder on growth performance,meat quality,antioxidant status and serum biochemical index of AA broilers,so as to explore the feasibility and optimum addition amount of bitter almond as feed additive in broiler diets.Methods: A total of 100 healthy(AA)broiler chicks were randomly divided into 4 groups with 5 replicates in each group and 5 broilers per replicate.And the control group was a blank control group,fed with basic complete ration.Groups A～C was the low,medium and high cyanogenic glycoside content groups respectively,fed with basic complete diet containing 7ppm,14 ppm and 27 ppm of cyanogenic glycoside in bitter almond powder(see Table 2-2 for specific groups).The test period was 45 days,the first 7 days were pre-feeding,and the test was officially started on the 8th day.During the first 1～21d days of the experiment,fed with young chicken feed,and during the second 22 to 45 days of the experiment,fed with Adult chicken feed.The growth performance related indexes were recorded during the feeding process,and biochemical indexes were detected by blood collection from the inferior pterygium vein after feeding.After slaughter,the pectoral muscles were taken to detect the meat quality and meat nutrition and other related indexes.The results showed as follows :(1)The effect of cyanogenic glycoside on the growth performance of broilers: compared with the control group,the daily gain of broilers in group c was significantly decreased(P<0.01)and the feed-to-meat ratio was significantly increased(P<0.01),which would lead to the reduction of the growth performance of broilers in the whole growth stage.However,the feed-to-meat ratio of group B broilers decreased,which would reduce the feed-to-meat ratio in the whole stage to a certain extent and improve the feed utilization rate.From day 1to 21 days,the growth performance of cyanogenic glycoside groups was no significant difference to compared with the control group.But,from day 22 to 45 days of the experiment,the growth performance indexes of broilers in Group C showed extremely significant increased compared to the control group.The results showed that the effect of cyanogenic glycoside addition to broiler diets on broiler growth performance was mainly in the late 22-45 days of the experiment.(2)The effect of cyanogenic glycoside on antioxidant and immune performance of broilers:compared with the control group,SOD and GSH-Px concentrations in liver of broilers in each cyanogenic glycoside concentration group were significantly increased and showed dose dependence(p<0.01);CAT content in group c was significantly increased(p<0.05).The indexes of thymus gland and bursa of fabricius in group c were significantly decreased(p<0.01).The spleen index of broilers in group b was significantly increased(P<0.05).The results showed that adding cyanogenic glycoside at different concentrations to broiler diets could improve the antioxidant capacity of broilers by increasing the concentration of antioxidant enzymes and eliminating lipid peroxides.Adding high-concentration cyanogenic glycoside(27mg/kg)to broiler diets will reduce the immune organ index of broilers.The spleen index was increased by adding a moderate dose of cyanogenic glycoside(14mg/kg).Further research is needed on whether cyanogenic glycoside can improve the immune ability of broilers.(3)The effect of cyanoside on the meat quality of broilers: After slaughtering for 45 minutes,the color value of broilers in group B rose significantly than that in the control group(P<0.05).After slaughtering for 24 h,the color value of the meat in group C declined significantly when compared with that in the control group(P<0.05).After slaughtering for2 h,the PH value of the control group declined the fastest when compared with that of the all cyanoside group.The p H value of the group B declined the most slowly,and there was a significant difference between the group B and the control group(P<0.05).After slaughtering for 24 h and 48 h,the PH value of group C declined significantly and the PH value declined the fastest when compared with the control group,(P<0.01).When compared with the control group,the shear force of the chicken meat in group C increased significantly(P<0.05)by 36%,while that in group A and B decreased by 9.8% and 15%,respectively.When each experimental group was compared,the drip loss in group A was the lowest,with a reduction of 36%,and that in group B reduced by 24%.The drip loss was the highest in group C,with an increase of 10.8%.There were an increasing among the protein contents of the cyanoside group with the low、medium and high concentrations when compared with the control group,and the group A increased significantly by 3.5%(P<0.05),while that in group B and C increased by 2.2% and 1.3%,respectively.Among the fat content of each experimental group,the group C increased by 14%.The results showed that adding cyanoside with medium concentration(14mg/kg)to the diet of broilers could improve the color value of chicken meat,improve the water power and tenderness of chicken,delay the decline of p H value,and improve the quality of chicken meat within 45 minutes.However,when the high concentration of cyanoside(27mg/kg)was added,the result was to degredate the quality of chicken.The addition of the low or medium concentrations of cyanoside(7mg/kg,14mg/kg)can help increase the protein content and improve the nutrition of chicken.(4)The effects of cyanoside on blood biochemical indexes and cytochrome oxidase of broilers: when compared with the control group,there was no significant difference in lipid metabolism related indexes and AST in each experimental group(P>0.05).The Crea concentration in group C increased significantly(P<0.01).There was no significant difference in liver cyclooxygenase in each experimental group(P>0.05).The results showed that adding cyanoside with the high concentration(27mg/kg)into the daily diets of broilers may cause the injury of renal functions.The addition of cyanoside at different concentrations in our experiment did not affect the cytochrome oxidase of broiler liver.Conclusion: Adding cyanoside with the low or medium concentration into the daily diet can improve the feed utilization rate,antioxidant capacity,chicken quality and protein content of broilers,and has no effect on lipid metabolism and liver and kidney functions of broilers.However,the addition of high concentration cyanoside can reduce the feed utilization rate of broilers,affect the muscle quality,and may cause the broilers’ s injury of kidney functions. |
