Linseed oil can decrease liver fat deposition and improve antioxidant ability of juvenile largemouth bass,...

Area of Science:

• Aquaculture Nutrition
• Fish Physiology
• Lipid Metabolism

Background:

• Fish oil (FO) is a primary source of essential fatty acids in aquaculture diets.
• Linseed oil (LO), rich in alpha-linolenic acid, is a potential alternative to FO.
• Understanding the impact of LO on fish health and metabolism is crucial for sustainable aquaculture.

Purpose of the Study:

• To evaluate the effects of dietary linseed oil (LO) on growth, plasma biochemistry, hepatic metabolism, and antioxidant capacity in juvenile largemouth bass (Micropterus salmoides).
• To determine the optimal level of fish oil (FO) replacement with LO in largemouth bass diets.

Main Methods:

• Juvenile largemouth bass were fed diets with 0%, 33.3%, 66.7%, and 100% FO replacement by LO for 8 weeks.
• Growth performance parameters (weight gain, feed intake, feed conversion ratio) were measured.
• Plasma biochemistry, liver metabolism enzymes (AMPK, PPAR-α, PEPCK, FBPase), and antioxidant status (SOD, CAT, GPx, iNOS, MDA) were analyzed.

Main Results:

• Complete replacement of FO with LO (100% LO) significantly reduced weight gain, specific growth rate, and protein efficiency ratio, while increasing feed conversion ratio.
• Dietary LO significantly decreased liver glycogen, lipid, non-esterified fatty acid, plasma triglyceride, and total cholesterol content.
• LO supplementation increased hepatic antioxidant enzyme activities (SOD, CAT, GPx, iNOS) and reduced malondialdehyde (MDA) levels, indicating enhanced antioxidant capacity.

Conclusions:

• Linseed oil can improve the liver function and antioxidant capacity of largemouth bass.
• Partial replacement of fish oil with linseed oil may not significantly affect growth performance.
• Complete substitution of fish oil with linseed oil negatively impacts the growth performance of largemouth bass.