Effect of dietary lipids on histological changes in hepatic tissues of Catla catla fingerlings

The aim of the study was to understand the impact of dietary lipids on the histological changes in liver of Catla catla fingerlings. Ninety advanced fingerlings (av. wt. 16 g) were randomly distributed in six treatment groups with three replicates each for an experimental period of 60 days. Six isoprotein (40.00–41.90%) and isocaloric (4260 kcal kg-1) semi-purified diets were prepared with varying levels of soybean oil (SBO) and cod liver oil (CLO) containing a total of 8% lipid viz., D₁ (Control), D₂ (8% SBO), D₃ (6% SBO and 2% CLO), D₄ (4% SBO and 4% CLO), D₅ (2% SBO and 6% CLO) and D6 (8% CLO). Histological studies of liver showed normal hepatocytes in D₂ and D₃ groups and inclusion of cod liver oil above 2% showed marked changes in the hepatocytes suggesting that the cod liver oil was a good source of essential fatty acids. The use of this oil in the diets of fishes should be limited due to the changes caused by it in the liver cells as it could affect the normal functioning of the liver.