Effects Of Different Pigment Sources, Proportion And Use Time On Skin Pigmentation In Yellow-Feathered Broilers

The objective of this study was to estimate the regularity of pigment deposition in chicken,and effects of different levels and combinations of pigments on pigmentatio n in broiler.This study contained three trials.In trail one and trial two: yellow-skinned chickens were used to estimate the effects of different sources and combination of pigments on skin coloration,and the regression models of pigment level in feed a nd skin coloration in chicken were established.Results showed that:(1)There was no difference of body weight gain and feed to gain ratio among treatments(P>0.05);Growth performance was observed no difference in chickens fed with corn-soybean meal diet or sorghum-barley diet(P>0.05).(2)The coloration of tightandback skinwere improved in broilers fed with pigment-contained feed in a dose–dependent manner(P<0.05).(3)The tight skin coloration and the back skin coloration were lower in chicken fed with diet contained 10% synthetic yellow pigment than chicken fed with diet added 2% natural lutein.To achieve the same pigmentationeffect of corn-based diet in chicken,1500g/t natural lutein(2%)and 50g/t red pigment(10%)should be recommended to add in sorghum and barley-based diet.(4)Different pigments showed different coloration effects of skin.Natural pigments exhibited better effect than synthetic pigments.The combination of synthetic pigments and red pigments showed better effect than synthetic pigments alone;Skin pigmentation was better in chicken feed with diet contained pigments for 21 days than 15 days.(5)According to the regression model of level and combination of pigment and skin coloration,the amount of pigment added in feed can be preciselydet ermined.(6)The pigmentation showed the same of chicken fed with sorghum and barley-based dietadded of 1500g/t natural lutein(2%)and 50g/t red pigment(10%)compared to chicken fed with corn-based diet.(7)The tight pigmentationwas observed nodifferencewhen chickens stored under 4? for twelve days.The coloration of back skin decreased after chickens stored under 4? for six days,however,coloration of back skin did not change from six to twelve days.