Effects Of Adsorbent On Growth,Distribution,Accumulation And Disappearance In Cadmium-Stressed Broilers

Due to the accumulation of heavy metals?cadmium,Cd?deposition in the soil caused by mining,there is an significant increase of Cd level in feed,and therefore,animal body,resulting in a direct threat to human health.This trial is conducted to evaluate the effects Cd stress on growth performance,health,the adsorption effect of adsorbent on Cd by exogenous addition of Cd for providing a scientific basis for promoting animal health breeding.Experiment 1:Effects of different levels of cadmium on broilers growth performance and body antioxidant capacityExperimental design:Forty-eight 5-week-old broilers were randomly divided into 3 blocks of 4 repeats with 4 broilers in each repeat.Animals were fed the basal diet?control?,basal diet+75 mg/kg Cd?treatment 1 group?,basal diet+150 mg/kg cadmium?treatment 2 group?for determination of growth performance,nutrients metabolic rate,plasma metabolites,liver antioxidant metabolites,and meat quality.The results showed that:?1?The final body weight of treatment 2 was lower than control and treatment 1?P<0.05?.Broilers in control had the highest average daily feed intake?ADFI?,which was higher than treatment 1 and treatment 2?P<0.05?.Control and treatment 1 resulted in higher average daily body weight gain?ADG?than treatment 2?P<0.05?.Treatment 2 had higher ratio of feed to gain?F/G?than control and treatment 1?P<0.05?.?2?The CP metabolic rate in control was higher than treatment 2?P<0.05?.?3?In terms of blood biochemical indicators,Glu in the 2treatments was lower than that in the control,AST,ALT were higher than the control and 1 treatment?P<0.05?;level of TG in control and treatment 1 was higher than that of treatment 2?P<0.05?;TP,ALB and T-CHO levels in treatment 1 and treatment 2were higher than those in control?P<0.05?;the highest LDL-C in 2 groups?P<0.05?.?4?In terms of plasma and liver antioxidants,there were no significant differences in plasma CAT,SOD and liver MDA among the groups?P>0.05?;Plasma and liver GSH-Px levels in treatment 1 and treatment 2 were lower than control?P<0.05?.Plasma GSH-Px in treatment 1 was higher than treatment 2?P<0.05?.Plasma MDA of treatment 1 and treatment 2 was higher than control?P<0.05?.Liver CAT for control and treatment 1 was higher than treatment 2?P<0.05?.?5?Cadmium treatment has no effect on broilers quality(p H_{45 min},p H_{24 h},meat color brightness,shear force,water loss,cooked meat rate;P>0.05).Conclusion:Cadmium can damage broilers growth,reduce feed intake,daily weight gain and nutrients metabolic rate,and cause functional dysfunction of broilers plasma and liver antioxidant systems.Experiment 2:Effect of adsorbent on the disappearance of low-dose cadmiumExperimental design:Sixty-four 5-week-old broilers were randomly assigned to 4blocks with 4 repeats in each group and 4 broilers in each repeat.Animals were fed the basal diet?control?,basal diet+75 mg/kg Cd?treatment 1?,basal diet+75 mg/kg Cd+2%adsorbent?treatment 2?,basal diet+75 mg/kg Cd+4%adsorbent?treatment 3?.The adsorbent was 1:1 combined with zeolite and maifanite.Broilers were used to determine the growth performance,nutrients metabolic rate,plasma metabolites,antioxidant metabolites,and Cd deposition in the body.The results showed that:?1?Level of ADFI in control and treatment 2 was higher than treatment 1 and treatment 3?P<0.05?.Treatment 3 had lower ADG over control,treatment 1,and treatment 2?P<0.05?.The F/G in treatment 1 was lower than treatment 3?P<0.05?.?2?The OM metabolic rate of control and treatment 1 was higher than treatment 2 and treatment 3?P<0.05?.The CP metabolic rate of treatment1 was lower than other 3 groups?P<0.05?.?3?Plasma Glu in control was higher than treatment 1?P<0.05?.Plasma TG and UA levels in control and treatment 1 were higher than treatment 2 and treatment 3?P<0.05?.The plasma AST of treatment 1 was higher than other 3 groups?P<0.05?and treatment 2 was higher than control?P<0.05?.The T-CHO and LDL-C of control were lower than other 3 groups?P<0.05?.The T-CHO in treatment 3 was higher than other 3 groups?P<0.05?,and treatment 1 was higher than control and treatment 2?P<0.05?.?4?Plasma GSH-Px in control and treatment 2 were higher than treatment 1?P<0.05?.Level of MDA in control was lower than other 3 groups?P<0.05?.Liver SOD of control was higher than other 3groups?P<0.05?.The liver GSH-Px in treatment group 1 and treatment group 2 were lower than those in control group?P<0.05?and treatment group 3?P<0.05?.?5?As for the cadmium depletion in broilers,the cadmium content in the tissues of the 3treatment groups?liver,kidney,leg muscle,pectoral muscle?at different sampling points?15 days,30 days,45 days,60 days?was higher than that of the control group?P<0.05?.Conclusion:Addition of adsorbent did not improve the growth performance of broilers,but it can increase the CP metabolic rate and can also alleviate the damage extent of Cd exposure on plasma metabolites and liver antioxidant indicators,and reduce the concentration of Cd level in the body.Experiment 3:Disappearance effect of adsorbent on growth and health of broilers by high-dose Cd stressExperiment design:Sixty-four 5-week-old broilers were randomly assigned to 4blocks with 4 repeats in each group and 4 broilers in each repeat.Animals were fed the basal diet?control?,basal diet+150 mg/kg Cd?treatment 1?,basal diet+150 mg/kg Cd+2%adsorbent?treatment 2?,basal diet+150 mg/kg Cd+4%adsorbent?treatment3?.The adsorbent was 1:1 combined with zeolite and maifanite.Broilers were used to assess the growth performance,nutrients metabolic rate,plasma metabolites,antioxidant metabolites,and Cd deposition in the body.The results showed that:?1?Control and treatment 2 had higher final weight than treatment 1 and treatment 3?P<0.05?.Treatment 1 had lower ADFI than other 3groups?P<0.05?.Treatment 2 had higher ADG than other 3 groups?P<0.05?and control and treatment 3 were higher than treatment 1?P<0.05?.Treatment 1 resulted in higher F/G than control,treatment 2,and treatment 3?P<0.05?.?2?The OM metabolic rate in control and treatment 1 was higher than treatment 2 and treatment 3?P<0.05?.The CP metabolic rate of treatment 1 was lower than other 3 groups?P<0.05?.?3?The plasma Glu in control was higher than treatment 1 and treatment 2?P<0.05?.Treatment 1 showed higher plasma ALT,TG,T-CHO levels than other 3groups?P<0.05?.Plasma AST among treatment 1,treatment 2,treatment 3,and control was gradually decreased in order?P<0.05?.Plasma level of TP in control was lower than treatment 1 and treatment 2?P<0.05?.Control and treatment 3 had lower plasma ALB than treatment 1 and treatment 2?P<0.05?.?4?Control had lower plasma GSH-Px than other 3 treatments?P<0.05?and lower MDA than treatment 1?P<0.05?.Liver CAT and GSH-Px for control were lower than other 3 treatments?P<0.05?.Liver SOD level for control,treatment 3,treatment 2,and treatment 1 was decreased sequentially?P<0.05?.?5?There was no difference for meat quality among the 4treatments?P<0.05?.?6?The 3 treatments resulted in higher Cd levels for liver,kidney,leg muscles,and pectoral muscles relative to control?P<0.05?.Conclusion:when feeding high-dose dietary Cd,2%and 4%adsorbents can improve broilers ADFI and ADG,reduce F/G,promote CP metabolism,and also improve plasma metabolites and antioxidative function.High Cd is mainly deposited in the kidney and liver and there is a time-effect and dose-effect.The addition of adsorbents can reduce Cd level in tissues,however,the reduction extent does not reach the national standard.Overall,it is indicated that Cd exposure can damage broilers growth;reduce feed intake,daily gain and nutrients metabolic rate;and cause antioxidant functional dysfunction of broilers plasma and liver.Adsorbents can improve broilers growth performance,promote broilers CP metabolism,and alleviate the damage extent of Cd exposure on plasma metabolites and plasma and liver antioxidant,and then,reduce the concentration of Cd in the body.