COMPARING THE ENRICHMENT OF LIVE FEEDS WITH a-TOCOPHEROL OR A MIXED TOCOPHEROL PRODUCT AND THEIR EFFECTS ON THE PERFORMANCE OF YELLOW PERCH Perca flavescens LARVAE

John D. Grayson*, Richard Bruno, and Konrad Dabrowski
School of Environment and Natural Resources
The Ohio State University
Columbus, OH 43210
grayson.37@osu.edu
 

Yellow perch is an important commercial and recreational finfish species in the Great Lakes region with considerable potential for aquaculture expansion. The optimization of feeding and nutrition in early life stages is vital for the commercial success of yellow perch production. Live food enrichment with polyunsaturated fatty acids (PUFA) is a commonly used technique in larval finfish culture, and elevated dietary PUFA often necessitates antioxidant supplementation. Concentrated α-tocopherol (α-T) is the most common form of vitamin E used as a dietary antioxidant, however mixtures of all tocopherol forms (α, β, γ, and δ) require less processing and are more sustainably sourced. This investigation examined the culture performance of yellow perch larvae during the first ten days of feeding with rotifers (Brachionus plicatilis) and Artemia nauplii enriched with PUFA and α-T or mixed tocopherol (mix-T) antioxidant supplementation.

Larvae were reared in a specialized recirculating system with nine 50 L conical tanks. Water was kept at 21.6±0.4˚C. Sea salt and microalgae concentrate were continuously added to maintain a salinity of 2.8±0.5 ‰ and a turbidity of 8.2±1.2 NTU. Enrichment emulsions contained 890 mg ω-3 PUFA and no tocopherol (Control PUFA), 235 mg*g-1 α-T (25% α-T), or 235 mg*g-1 mix-T (25% mix-T; TC-70 Natural Mixed Tocopherols, Organic Technologies®, Coshocton, OH). The lipid and tocopherol composition of live feeds and yellow perch were assessed using gas chromatography and high-performance liquid chromatography.

The treatment groups had statistically significant differences (α=0.1) in fish survival and final weight at the end of the feeding period (Figure). The mix-T group had the fastest growth, but lower survival than the α-T group. While differences in survival are statistically significant, all group means were within 5% of each other. These data suggest that tocopherol supplementation to live food PUFA enrichments is beneficial to the culture of yellow perch larvae, and that mix-T may have unclear impacts compared to α-T.