Abstract
L‐carnitine is a multi‐functional nutrient which plays a leading role in fatty acid metabolism in mammals and other eukaryotes. Its main physiological function is to promote fatty acid β‐oxidation to produce energy, which reduces body fat content and improves body weight without affecting moisture content in whole body and muscle. In recent years, its dietary supplementation in aquaculture nutrition has been studied in different cultured species. It has been proved that L‐carnitine can improve growth and increase lipid utilization rate in some aquatic animals. However, such beneficial effects of dietary L‐carnitine are limited or absent in other species. The reasons for the conflicting results obtained on L‐carnitine functions in aquatic animals need to be elucidated. This review explores comprehensively the different physiological functions of L‐carnitine in various aquatic animals. In the end, research strategies are provided to elucidate the existing conflicts on dietary L‐carnitine application in aquaculture nutrition in order to promote its utilization in aquatic feed industry.