Effect of dietary Mirex and PCB's on hepatosomatic index, liver lipid, carcass lipid and PCB and Mirex bioaccumulation in yearling coho salmon, oncorhynchus kisutch

Abstract

1. Hepatosomatic indices were significantly increased ( P < 0.01) in yearling coho salmon fed PCB diets (1.76 ± 0.07) and a mixed PCB-Mirex diet (1.42 ± 0.04) and significantly decreased ( P = 0.05) in salmon fed Mirex diets (1.15 ± 0.03) compared with controls (1.27 ± 0.03). 2. Liver lipid reserved (LLI) in PCB-fed fish (99.0 ± 16.6) were significantly increased ( P < 0.01) and carcass lipid (34.2 ± 3.0 mg/kg) significantly decreased ( P = 0.05) compared with controls (57.6 ± 6.7 for LLI and 50.8 ± 5.9 mg/kg for carcass lipid). 3. The LLI in Mirex-fed coho (55.7 ± 5.6) was similar to the controls although carcass lipid (22.5 ± 5.8 mg/kg) was significantly lower ( P < 0.01). 4. Carcass PCB levels in coho fed the high PCB diet (500 mg/kg) were only 3.2 fold higher than coho fed the low PCB diet (50 mg/kg), and Mirex levels in coho fed the high Mirex diet (50 mg/kg) only 6.0 fold higher than in coho fed the low Mirex diet (5 mg/kg). 5. Carcass PCB levels in coho fed a mixed PCB (50 mg/kg)-Mirex (5 mg/kg) diet were significantly higher ( P < 0.01) than in fish fed the low PCB diet; carcass Mirex levels in low Mirex diet-fed and mixed diet-fed coho were similar.