The importance of vitamin E for farmed fish — A review

Abstract

Vitamin E (VE) is composed of a group of fat-soluble molecules, from which the most active homologous is α-tocopherol. VE is a structural component of cell membranes with a potent chain-breaking antioxidant action, which plays a main role in several biological processes. In cultured fish, VE can prevent peroxidation of cellular and subcellular membrane phospholipids and also red blood cells, leading to maintaining the structural and functional integrity of animal cells. VE performs several other biological and metabolic functions, including improvement of the immune response, enhancing growth performance and feed efficiency, preventing muscle degeneration, reducing the risk of atherosclerosis, improving reproductive efficiency and larval performance, meat quality and shelf life of seafood. Besides, VE interacts with other micronutrients, especially vitamin C and selenium. Fish feed and fish flesh generally contain high concentrations of lipids, especially polyunsaturated fatty acids, which renders these lipids more susceptible to lipid peroxidation. Supplemental VE may, therefore, become necessary to prevent this peroxidation. However, the VE requirement of farmed aquatic animals varies significantly, depending on dietary contents of VC, selenium and lipid (unsaturated fatty acids). This review summarizes the current knowledge on the physiological functions of VE in farmed fish and shrimp, and the effects of supplemental VE on fish performance, reproduction, health and product quality. The future considerations of VE requirements of farmed fish in light of the predicted climate change have also been discussed, especially with regard to feed input supplies (fish meal and fish oil vs. plant proteins and oils) and weather temperature.