The Effect Of Beta-Carotene On Broilers Performance,Pigmentation And Anti-heatstress Ability

This study included two experiments to part discern to the effect of Beta-carotene on growth performance,pigmentation and anti-heatstress ability of broilers.1.Experiments 1144 8-day-old Avian broiler chickens were randomly allocated into 6 groups of 4 replicates of 6 broilers each.The experimental period is from day 1 to 42,during which, two-phase trial(2～4w,5～7w) were conducted.The feeding trail was designed as follows:the supplementation of beta-carotene to basal feed is 150,600,1000,2000mg/kg for group 1,2,3,4,respectively.1%Beta-carotene of fermentation and group 5 +50mg/kg 10%canthaxanthine.Body weight and feed consumption were recorded at 8,28,49 days. On the first day of trial and last day of every phase,2 broiler chickens from each replicate were killed,by jugular bloodletting and blood samples were collected.The objective of present study were conducted to study the effect of Beta-carotene and canthaxanthine on growth performance,antioxidative capability,pigmentation and blood biochemistry index of broilers and then to investigate the effects of Beta-carotene on growth performance and pigmentation.The results showed as follows:The growth performance:The resulted showed that from the whole trial period,the supplementation of Beta-carotene increased average daily gain(ADG) and decreased feed/gain ratio compared to the control group,of which,ADG in group 2 dramatically increased by 8.65%compared to control groups(p＜0.05).Average daily feed intake (ADFI) in group 4 increased by 5.03%compared to control groups(p＜0.05),while decrease was observed in other groups,however,no significant difference was observed (p＞0.05).There is a significant decrease in feed/gain ration of group 2 and 3 compared to control groups(p＜0.05).In the fifth to the seventh week,however,no significant difference was observed in ADG compared to control group(p＞0.05).ADFI showed the same tendency in all treatments,while ADFI significantly decreased by 7.17%in group 4 (p＜0.05),feed/gain in group 2 significantly decreased compared to control groups (p＜0.05).The antioxidative capability:The Beta-carotene supplementation significantly increased on SOD and T-AOC activity in serum and liver(p＜0.05),and the highest level of which observed in group 2.Comparing to control group,MDA concentration in serum and liver was decreased in all treatments,while MDA concentration in group 2 were significantly decreased(p＞0.05).However,no significant difference was observed in SOD,MDA and T-AOC concentration of serum and liver(p＜0.05),when broiler chickens were fed 50mg/kg canthaxanthine diet.The biochemical parameters in serum:The supplementation of Beta-carotene and canthaxanthine in diet had no significant effect on the concentration of T₃,T₄,glucose and activity of enzyme LDH,CK,AST,ALT,albumin and Tot Prot in serum among all dietary treatments(p＞0.05).In the second to the fourth week,all treatments with supplementation Beta-carotene and canthaxanthine had no significant effect on total cholesterol concentration in serum(p＞0.05).The maximum HDL-C concentration was observed in the treatment 3 group(p＜0.05),while the minimum HDL-C concentration appeared in control group.The Beta-carotene groups significantly decreased LDL-C concentration in serum compared to the control groups(p＜0.05).In the fifth to the seventh week,the cholesterol concentration in treatment 2 and 4 was significantly lower in serum compared to the control group(p＜0.05).All treatments improved concentration in serum compared to the control group,but there were no significantly effect on HDL-C and triglyceride in serum(p＞0.05).The treament 2 group decreased significantly on LDL-C concentration compared to control group(p＜0.05).The canthaxanthine diet also had no significantly effect of TCHO,TG,LDL-C,HDL-C in serum(p＞0.05).The slaughter performance:Throughout the whole experiment,the addition of Beta-carotene and canthaxanthine diets showed no significantly effect on naked body ingredient,and there was little increased on liver exponent and immune organ exponent compared to the control group,but had no significantly effect(p＞0.05).The body pigmentation:The canthaxanthine treated diet elevated obviously by chest fur skin,crura fur skin,back fur skin,foot cervical part and muscle pigmentation(p＜0.05); in contrast,Beta-carotene treated groups increased little on the naked body pigmentation. In the second to the fourth week,compared to the control group,the treament 3 group improved significantly on chest fur skin,crura fur skin pigmentation(p＜0.05),and the treatment 2,3 groups raised obviously back fur skin chroma(p＜0.05),muscle pigmentation in all treatments are significantly increased,compared to control group (p＜0.05).2.Experiments 296 8-day-old Avian broiler chickens were randomly allotted into 4 treaments of 4 replicates of 6 each.Group 1 is control group with feeding basal diet;experiment1,2,3 group in heatstress +600,1000mg/kg 1%Beta-carotene of fermentation and 50mg/kg 10% canthaxanthine.Body weight and feed consumption were recorded at 8,28,49days of experiment.On the first day of trial and last day of every phase,2 broiler chickens from each replicate were killed by jugular bloodletting and blood sample were collected.The results showed as follows:The growth performance:From the whole rearing period,high temperature had Severity effect on ADFI,ADG(p＜0.05) and feed/gain ratio(p＞0.05) of broiler chickens. As compared to the control group which were under the high-temperature,ADFI and ADG was significantly increased in the group of addition of Beta-carotene(p＜0.05),but there were no significantly decreased on feed/gain ratio(p＞0.05).In contrast,the addition of the canthaxanthine have no significantly increased on ADFI and ADG(p＞0.05). Meanwhile ADG in all treatments with supplementation of Beta-carotene was significantly reduced compared to the control 1 group(p＜0.05).The antioxidative capability:As compared to control groups with high temperature, all Beta-carotene and canthaxanthine groups broiler chickens fed beta-carotene addition diet displayed higher levels of SOD capability in serum and liver,meanwhile they decreased by MDA concentration,and the lowest MDA concentration was observed in treatment 2;In addition,both serum and liver of T-AOC levels in the treatment 1,2 groups were significantly elevated(p＜0.05).In contrast,the addition of the canthaxanthine have no significantly effect on SOD,MDA and T-AOC(p＞0.05).The biochemical parameters in serum:T₄ in serum concentration during in high temperature was significantly decreased in the second to the fourth week(p＜0.05). Throughout the whole experiment,compared to control group,the addition of canthaxanthine had no significantly effect on T₃,T₄ concentration(p＞0.05).In the fifth to the seventh week,there were significantly decreased on T₃ in serum concentration during in high temperature(p＜0.05).The treament 2 groups had significantly increased on T₄ compared to control 2(p＜0.05).There were significantly improved on LDH,CK,AST and ALT capability in high temperature compared to control 1(p＜0.05).Altogether the Beta-carotene and canthaxanthine treated groups had no signicantly effect on blood glucose(p＞0.05).The addition of 10mg/kg Beta-carotene had significanly decreased on LDH,CK,AST and ALT capability comparing to control 2(p＜0.05).Through out the whole experiment,albumin and Tot Prot in serum were reduced in high temperature. There were different effect on albumin and Tot Prot in serum of the addition of Beta-carotene and canthaxanthine.In the second to the fourth week,all Beta-carotene and canthaxanthine treated groups got significantly increased on albumin and Tot Prot compared to control 2(p＜0.05).In the fifth to the seventh week,the addition of 10mg/kg Beta-carotene had significantly increased on albumin in serum compared to control 2 (p＜0.05),whereas Tot Prot of all treatment groups had no significantly effect(p＞0.05). The addition of Beta-carotene and canthaxanthine got no significantly effect on lipide index in serum in high temperature(p＞0.05).The slaughter performance:There were no significantly effect on naked body ingredient of broiler chickens in high temperature,while belly fat rate significantly elevated compared to control 1 group(p＜0.05),and the high temperature control group also showed litter decreased on immunity organ exponent(p＞0.05) and significantly decreased on liver exponent(p＜0.05).In the second to the fourth week,except belly fat rate,Beta-carotene and canthaxanthine did not significantly effect the slaughter performance in high temperature(p＞0.05).On the other hand,in the fifth to the seventh week,the addition of Beta-carotene diet had significantly elevated by eviscerated carcass rate,breast muscle rate and crura muscle rate compared to control 2(p＜0.05),while the 10mg/kg Beta-carotene diet also showed significantly lower belly fat rate(p＜0.05).In addition,both Beta-carotene and canthaxanthine got the tendency of increased on immunity organ exponent,but they had no significantly effect compared to control 2 (p＞0.05),meanwhile liver exponent was significantly increased when added 10mg/kg, compared to control 2(p＜0.05).The body pigmentation:High temperature may be had obvious effect on pigmentation and reduced naked body chroma.Compared to control 2,the addition of canthaxanthine diet got significantly increase on the chroma of chest fur skin,crura fur skin,back fur skin,foot cervical part and muscle(p＜0.05);in contrast,Beta-carotene diet also showed litter increase on the naked body pigmentation,but the extent of improving was lower than the addition of canthaxanthine diet,extraordinary with regard to foot cervical part.The nutritional composition of muscle:High temperature may effect on the nutritional composition of muscle and reduced crude protein and crude fat.Throughout the whole experiment,the treament 2 group increased on crude protein of breast and crura muscle compared to control 2(p＜0.05).In the second to the fourth week,the treament1,2 groups improved remarkably by crude fat compared to control 2(p＜0.05),while they was remarkably decrease comparing to control 1(p＜0.05).However,the addition of Beta-carotene were no significantly effect on crude fat of breast and crura muscle in later stage(p＞0.05).In conclusion,these results suggest that the addition of Beta-carotene significantly enhanced the growth performance and antioxidative capability,and released heatstress effects on the growth performance and tissue damage in Avian broilers.Meanwhile Beta-carotene treated diet may improved the naked body pigmentation.In contrast,the canthaxanthine diet increased significantly on the chroma of chest fur skin,crura fur skin,back fur skin,foot cervical part and muscle,however,however,no significant effect was observed in the growth performance,antioxidative capability and anti-heatstress ability.