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4E - Food Safety (TH9/5) Polychlorinated biphenyls (PCBs) in broiler chicken diets: digestibility and incorporation in body tissues. Maervoet, Johan1, De Vos, Sven2, Chu, Shaogang1, De Schrijver, Remi2, Schepens, Paul1, 1 Toxicological Centre, University of Antwerp, Wilrijk, Belgium, Belgium2 Laboratory for Nutrition, Catholic University of Leuven, Leuven, Belgium, Belgium ABSTRACT- Broiler chickens (n=108) received ad libitum diets which differed in amount of added fat (4, 6, and 8%) and supplemented PCB levels (0 ng, 3 ng and 12 ng/g diet). PCBs were added to diets as a mixture of 7 reference congeners (IUPAC no. 28, 52, 101, 118, 138, 153 and 180) in peanut oil. After 2, 4 and 6 weeks, samples were taken and abdominal adipose tissue, breast and thigh muscle tissue and excrements were analyzed for their fat and PCB content. Neither fat nor PCB content significantly affected apparent fat digestibility. With regard to apparent PCB digestibility, there was no significant effect from dietary fat content. In contrast, higher apparent PCB digestabilities were observed when higher amounts of PCBs were added to the diets. PCB accumulation in the animal tissues was clearly dependent upon the administered dose, but not upon fat content. PCBs 52 and 101 presented a higher degree of metabolisation, while the other congeners were accumulated. The fat fraction in breast muscle contained higher amounts of PCBs than in thigh muscle when treatment groups with equal PCB ingestion were compared. On a tissue weight basis however, thigh muscle contained higher PCB levels due to a higher fat content. PCB levels in abdominal fat correlated best with PCB intake (r=0.96 , p<0.01 at 6 weeks) and can be used for monitoring. National Belgian limits of 200 ng/g lipid weight were never exceeded which creates room for a lowering of the maximum allowable PCB content in chicken and consequently in the animal feed. Key words: chicken, pcbs, accumulation, regulations |
