The Effects Of Dietary Marigold Extract On Pigmentation,Meat Quality,Antioxidant And Immune Capacity In Broilers

Yellow poultry products are loved by people.Neither the broiler itself can synthesize pigment,nor typical corn and soybean based commercial diets provide adequate numbers and types of pigments to meet consumers' preference for yellow chicken products.In order to cater to the market demand,synthetic pigments are usually added into poultry feeds to enhance the yellowness color of poultry products in commercial production now.Although synthetic pigments are more stable in nature and lower in price,its security has been questioned by consumers all the time.Recently,the interest of the development and application of natural pigment substitutes in poultry production is increased because of potential health promoting functions of natural pigments.Marigold extract is a xanthophyll pigment mixture extracted from marigold flowers.Its active ingredient is the lutein,a kind of carotenoid.Marigold meals and its extract are most widely accepted products in poultry feeds among natural pigment.The purpose of this study was to conduct the effect of dietary marigold extract on pigmentation,meat quality,antioxidant and immune capacity in broiler chickens by adding different levels of marigold extract in broiler feed,thus providing a theoretical reference for the rational use of marigold extract in broiler industry.The main studying contents and the test results were as follows:1.This experiment was conducted to investigate the effects of dietary supplementation with marigold extract on growth performance,carcass characteristics,muscle antioxidant capacity and meat quality in broiler chickensA total of 320 one-day-old Arbor Acres(AA)chickens were randomly divided into 5 groups with 8 replicates of 8 chickens each.The chickens of control group were fed with basal diet and other experimental groups were fed with basal diet added 0.075%,0.15%,0.30%,0.60%marigold extract respectively(the concentrations of lutein were 15,30,60,120 mg/kg respectively).Test period was 42 days.The results showed as follows:Compared with the control group,1)the T-AOC of thigh and breast muscles of 0.30%and 0.60%marigold extract groups were significantly increased(P<0.05),the SOD activities of thigh muscles of all marigold extract groups were significantly increased(P<0.05),while the content of MDA was significantly decreased(P<0.05);2)the drip loss and shear force value of thigh and breast muscles were significantly decreased in marigold extract groups(P<0.05),meanwhile,the hardness and chewiness of breast muscles were significantly decreased(P<0.05),the a*of thigh muscle of 0.60%marigold extract group increased significantly(P<0.05);3)there was no significant difference on growth performance and carcass characteristics at 21 d and 42 d(P>0.05).The results indicated that,dietary supplementation with marigold extract could increase the antioxidant capacities and the water holding capacity and tenderness of thigh and breast muscles,thus improve the meat quality in broiler chickens.2.This experiment was conducted to investigate the effects of dietary supplementation with marigold extract on pigmentation and expression quantity of related genes in broiler chickensExperiment design was the same with experiment 1.The results showed as follows:Compared with the control group,1)the b*of skin,breast and thigh muscle of 0.15%,0.30%and 0.60%marigold extract groups increased significantly(P<0.05),the yellow scores of shank and beak increased with the time,there was a high positive correlation between color scores and additive amounts of marigold extract,the yellow score of shank of 0.30%marigold extract group had reached the maximum.2)the BCD02 mRNA abundance in liver and shank skin of 0.60%marigold extract group increased significantly(P<0.05),at the same time,the TYR mRNA abundance decreased significantly(P<0.05).The results indicated that,dietary supplementation with marigold extract could significantly increase the yellowness of all parts such as shank,beak,skin and muscle in broiler chickens,and the supplementation of marigold extract will affect the expression of BCD02 and TYR genes.3.This experiment was conducted to investigate the effects of dietary supplementation with marigold extract on the biochemical indexes,antioxidant and immune capacities of serum in broilersA total of 192 one-day-old Arbor Acres(AA)chickens were randormly divided into 3 groups with 8 replicates of 8 chickens each.The control group chickens were fed with basal diet and other test groups were fed with diet added 0.15%?0.60%marigold extract(the contents of lutein were 30,120mg/kg),respectively.Test period was 42 days.The results showed as follows:Compared with the control group,1)the contents of TG and LDL-C of serum of 0.60%marigold extract group at 21 d and 42 d were significantly decreased(P<0.05),while the content of HDL-C was significantly increased(P<0.05);2)the T-AOC,SOD,GSH-PX and CAT of serum of 0.15%and 0.60%marigold extract groups at 21 d and 42 d were significantly increased(P<0.05),the T-AOC,SOD and GSH-PX of liver of 0.60%marigold extract group at 21 d and 42 d were significantly increased(P<0.05),while the content of MDA were significantly decreased(P<0.05);3)The indexes of thymus,spleen and bursa of 0.60%marigold extract group at 21 d were significantly increased(P<0.05),the contents of IgM,IgG and IL-2 of serum were significantly increased(P<0.05),there was no significant difference on immune organ indexes at 42 d(P>0.05).The results indicated that,dietary supplementation with marigold extract could increase the antioxidant and immune capacities of bodies and regulate blood lipids metabolism in broiler Chickens.