Correlation of Diets High in n-6 Polyunsaturated Fatty Acids With High Growth Rate in

Lipids and, in particular, fatty acids (FA), are well known as dietary components that supply energy and act as pheromones, hormones, and components of membranes. Fish are unable to synthesize de novo polyunsaturated fatty acids (PUFA), also known as highly unsaturated fatty acids (HUFA), including the essential fatty acids, such as linoleic (18:2 n-6) and linolenic acid (18:3 n-3); therefore, they must obtain these substances through food (1). In contrast to omnivorous fish like zebrafish, carnivorous fish are unable to elongate and desaturate FA, and thus, they must take up all necessary FA from their prey. A lack of essential FA has been found to cause a variety of problems such as fin erosion, reduced reproduction, and decreased growth (2). The requirement of essential FA for food fish raised in aquac-ulture is well known, and most fish have a species-dependent need for n-3 and n-6 FA. Coldwater fish have a higher require