Lipid metabolism in rainbow trout ( Salmo gairdnerii) fed diets containing partially hydrogenated fish oil

Abstract

1. 1. Rainbow trout were fed diets containing either 15% crude fish oil (CFO), 11.5% partially hydrogenated fish oil (PHFO) and 3.5% CFO, or 15% PHFO. 2. 2. Fish maintained on PHFO exhibited the highest death and lowest growth rates. CFO- and PHFO + CFO-fed fish had similar death and growth rates. After 15 months, PHFO + CFO fish had larger hearts and livers than fish fed CFO. 3. 3. Plasma cholesterol and triglyceride concentrations were similar in CFO and PHFO + CFO-fed fish and lowest in the group fed PHFO. 4. 4. Tissue lipids of PHFO + CFO fish were richer in 18:1 and less unsaturated than those of the CFO group. PHFO was richer in 22:1 than CFO, but the 22:1 contents of tissue lipids of PHFO + CFO and CFO fish were similar and less than those of the dietary oils. 5. 5. Cyanide-insensitive palmitoyl-CoA oxidation activity in liver was highest in trout fed the PHFO + CFO diet, while carnitine palmitoyltransferase was not affected by diet. 6. 6. It is suggested that the excess of long chain monoenes in relation to polyunsaturates in a PHFO + CFO diet causes an induction of the peroxisomal β-oxidation of fatty acids in fish liver.