The Distribution Characteristics Of Polybrominated Dipheny Ether In Feed And Biological Accumulation And Transformation In Chicken

Polybrominated biphenyl ether?PBDEs?can biomagnify through the food web,thus expose potential risks to animals and human health.Diet is considered as the most important animals and human exposure path way for PBDEs.As an important source of PBDEs in animals,feed has not been systematically evaluated.Poultry is a kind of typical food,and the metabolism,migration,and accumulation patterns of PBDEs in different growth stages of chickens are helpful for evaluating human exposure from the food,but such information is scarce.Therefore,two dependent researches were conducted in this study.Firstly,we collected the major domestic famous brands of feeds and its raw materials and examined the levels and source of PBDEs in these feeds and raw materials,finally assessed the potential health risks based on feeds.Secondlly,female chickens were fed with food spiked with BDE-209 at 85 mg/kg?wet weight?,chickens were continuously exposed to BDE-209 through diet for 50 days.We intended to characterize the intake,accumulation,metabolism,and excretion of BDE-209 and its main metabolites in various tissues at different growth periods.This could provide basic data for the accumulation and transformation of polybrominated biphenyl ether in animals and human.Polybrominated biphenyl ether in domestic animal feeds collected in China,including fish,poultry and pig feeds as well as their raw materials,were analyzed.?₈PBDE concentrations were 0.25–5.7?average:1.0?ng/g dry weight?dw?in animal feeds,and 0.27–0.84?average:0.44?ng/g dw in raw materials.The average concentrations of PBDEs in feeds followed fish?1.7 ng/g dw?>chicken?1.2 ng/g dw?>pig?0.90 ng/g dw?>duck?0.53 ng/g dw?.However,analysis of variance?ANOVA?demonstrated no statistically significant difference in?₈PBDE concentrations among these four groups of animal feeds.The average?₈PBDE concentrations in animal feeds of different brands followed a sequence of Others?1.5ng/g dw?>Zhengda?1.1 ng/g dw?>Shuangbaotai?0.77 ng/g dw?>Baoshun?0.65ng/g dw?>Yangzhiyuan?0.36 ng/g dw?.Brand Yangzhiyuan contained statistically?P<0.01?lower?₈PBDE levels than all the other brands except for Baoshun.BDE-209 was the dominant congener in all animal feeds analyzed,accounting for 65–100%of?₈PBDE concentrations.Similarly,BDE-209 was also the most abundant?60–100%?BDE congener in raw materials.BDE-209 was the most important contaminant among all feed types,and the abundance of BDE congeners in feeds followed BDE-209>BDE-153>BDE-28>BDE-183>BDE-99>BDE-47>BDE-154>BDE-100.Except for BDE-209,concentrations of?₇PBDE?sum of BDE-28,47,99,100,153,154,and 183?ranged from ND?<reporting limit?to 0.080 ng/g in ordinary fish meal and ND to 0.070 ng/g dw in super fish meal,indicated the heavier pollution of BDEs in source materials than feeds?ND–0.040 ng/g dw?.However,?₈PBDE concentrations in feeds of all brands except for Yangzhiyuan were higher than those in raw materials,suggesting additional contamination sources of PBDEs existed in feed production and sales process.In addition,chicken was selected as a main edible meat to assess human exposure risks via the consumption of chicken raised by feeds investigated in this study.Hazard quotients of feeds did not exceed the threshold of the risk assessment model,indicating that consumption of chicken raised with feeds under investigation posed low potential risk to human.The results of the present study suggest that the usage pattern of feeds in mainland of China may have to be adjusted with controlled procedures to minimize contamination of raw materials for animal feeds.On the other hand,concentrations of BDE-209 and its metabolites in exposed chicken tissues increased over time in a tissue-specific manner;they were the greatest in liver and generally the lowest in breast meat during the entire exposure period.The kinetic patterns were dependent on both dilution from continuous growth of the organs,and on accumulated concentrations of BDE-209.Tissue concentrations of?₈PBDE followed the sequence of blood>liver>intestine>leg meat>skin>stomach>breast meat.Different tissue partition coefficients and perfusion rates for blood may have resulted in different PBDE concentrations in tissues.Small portions of BDE-209 appeared to be debrominated to BDE-47,99,100,and 183.The absorption efficiency of BDE-209 in chicken tissues followed the sequence of liver?0.15±0.032%?>skin?0.14±0.038%?>intestine?0.071±0.021%?>breast meat?0.062±0.020%?>leg meat?0.059±0.016%?>stomach?0.021±0.0095%?,likely due in part to facilitated absorption of BDE-209 by transport proteins?P-glycoproteins?.On average,9.3±1.7%of BDE-209 was excreted in feces.Estimated human average dietary intake via the consumption of chicken tissues of?₈PBDE for adults and children was 320 and 1400 ng/day for liver,210 and 630 ng/day for leg meat,and 100 and 310 ng/day for breast meat from the contaminated group.Liver clearly poses the highest exposure risk for human consumption,particularly if chickens are fed with contaminated feed.