Evaluating different levels of α-tocopherol supplementation for Live Food PUFA Enrichments and their influence on the survival, growth, and condition of yellow perch Perca flavescens larvae

Yellow perch (Perca flavescens) is an important commercial and recreational finfish species in the Great Lakes region with great potential for aquaculture expansion. The optimization of feeding and nutrition, especially in early life stages, is necessary for the commercial success of yellow perch production. Live food enrichment with polyunsaturated fatty acids (PUFA) is a commonly used technique for increasing the growth and survival of larval fish, but increased dietary PUFA can also be a major source of oxidative stress. This investigation examined the intensive culture performance of yellow perch larvae during the first ten days of feeding with rotifers (Brachionus plicatilis) and Artemia nauplii enriched with PUFA and three levels of α-tocopherol (α-T) antioxidant supplementation.

Larvae were reared in a specialized recirculating system with nine 50-L conical tanks equipped with surface spray. Water was kept at 22.6±0.6˚C and evaporated salt and marine microalgae were continuously added to maintain a salinity of 2.3±0.3 ‰ and a turbidity of 9.3±1.1 NTU. Enrichment emulsions contained 754 mg PUFA and 0, 155, or 260 mg α-T *g^-1 dry weight (Control PUFA, 25% α-T, and 50% α-T, respectively). The fatty acid and tocopherol composition of live feeds and yellow perch were assessed using gas chromatography and high-performance liquid chromatography.

The treatments correlated with significant differences (α≤0.1) in fish survival and final weight at the end of the feeding period (Figure). The α-T content of both live foods and the fish were significantly influenced by treatment, with the supplemented groups having greater concentration than the Control PUFA group (p<0.001). The only significant difference between the 25% α-T and 50% α-T groups was in yellow perch α-T concentration (p=0.038). These data suggest that α-T supplementation to live food PUFA enrichments is beneficial to the intensive culture of yellow perch larvae, and that 260 mg α-T *g^-1 has no significant benefit over 155 mg α-T *g^-1.