Growth Response of Blue Tilapias to Selected Levels of Dietary Menhaden and Catfish Oils

Abstract

Blue tilapia (Tilapia aurea) fingerlings were fed a series of nine semipurified diets containing 0, 2.5, 5.0, 7.5 or 10% lipid in the form of menhaden oil or catfish oil over a 10-week experimental period. The study, conducted in flow-through aquaria, demonstrated that best growth and food conversions were obtained from fish fed the 10% menhaden oil diet. Total levels of the linolenic family (ω-3) of fatty acids were highest in the menhaden oil diets (up to 2.5%). In no instance did linolenic acid reach 1.0% of the total diet. That result supports the conclusion that growth reductions observed in tilapia and other fish species fed diets approaching 1% dietary linolenic acid are due to that specific fatty acid, and are not caused by the addictive effect of dietary ω-3 fatty acids.