Fat content and morphology of liver and intestine of Atlantic salmon (Salmo salar): Effects of temperature and dietary soybean oil

Summary

We investigate the effect of adding soybean oil (SO) to the diet of Atlantic salmon and water temperature on lipid composition and morphology of the liver and intestine. The fish were fed fish meal-based diets supplemented with either 100% fish oil (100% FO), 50% soybean oil (50% SO) or 100% soybean oil (100% SO) for 950 day degrees at 5 and at 12 degrees C. Fish fed the 50% SO and 100% SO diets had higher percentages of 18:2n - 6 and 18:1n - 9 in the triacylglycerol (TAG) fractions of liver and intestine than fish fed the 100% FO diet, at both temperatures. In addition, the percentages of 20:5n - 3 and 22:6n - 3 were considerably lower, while the percentages of 20:4n - 6 and 20:4n - 3 were higher in the phospholipids (PL) fractions of both liver and intestine of fish fed diets containing SO. Both morphological and chemical analyses revealed higher accumulation of fat both in the intestine and liver at 5 than at 12 T. Diets, on the other hand, did not affect the fat content of the intestine on the contrary to what was found in the liver. Fish fed the 100% SO diet had higher accumulation of fat in the liver than fish fed the 100% FO diet at 5 T. The higher fat accumulation in liver from 100% SO fed fish seemed to be mainly caused by a selective accumulation of 18:2n - 6 and 18:1n - 9. (c) 2005 Elsevier B.V. All rights reserved.