Toxicological Response Of Rats Fed Lake-Ontario Or Pacific Coho Salmon For 28 Days

The present study was undertaken to determine if the feeding of Lake Ontario salmon containing a mixture of chemical contaminants, could produce a toxicological response in rats. Male and female rats were fed freeze‐dried Lake Ontario or Pacific Coho salmon for 28 days at levels of 1.45%, 2.90% and 5.80% of their normal diet. Body weight changes, organ weights, food intake, routine hematology, biochemical parameters, residue levels and gross and microscopic pathological changes were determined. Body weight gain was decreased in all groups of male rats fed Lake Ontario or Pacific salmon but this was attributed to the unpalatibility of the diet since the food intake in these groups was decreased during the first week of the study. No effects were observed on body weight gain or food intake in female rats. Hematological parameters including hemoglobin, hematocrit, white blood count and red blood count were not affected by treatment. Serum potassium levels were significantly decreased in all three groups of male rats receiving Pacific salmon and in the two highest groups of female rats receiving the Pacific fish. Hepatic mixed function oxidase activity was increased in both males and females of the two highest Lake Ontario treatment groups. There appeared to be an altered steroid hormone metabolism in female adrenals which occurred only in Pacific Coho groups. Altered steroid metabolism in male adrenals was also observed but this occurred in both Lake Ontario and Pacific groups. Minor histological changes were observed in thyroid and liver of males and females fed Lake Ontario salmon and were attributed to the contaminants found in this fish source. Lesions of the kidney were observed in all female groups receiving either source of salmon but these could not be attributed to any specific contaminants. The results obtained here indicate that the feeding of Lake Ontario salmon results in certain biochemical and histological changes in male and female rats which are attributed to chemical residues found in those fish.