Evaluation of crude palm oil and refined palm olein as dietary lipids in pelleted feeds for a tropical bagrid catfish Mystus nemurus (Cuvier & Valenciennes)

The effects of different dietary lipids on the growth, feed utilization and tissue fatty acid composition of a tropical bagrid catfish Mystus nemurus (Cuvier & Valenciennes) were investigated. Eight isonitrogenous and isoener getic semi-purified diets were fed to triplicate groups of M. nemurus finge rlings for 10 weeks. Diet lipid levels were fixed at 10%, with 1% coming fr om residual oil in fishmeal and the remainder from cod liver oil (CLO), cor n oil (CORN), soybean oil (SBO), crude palm oil (CPO), refined, bleached an d deodorized palm olein (RBDPO) or various combinations of these oils. Catf ish fed diets supplemented with 9% RBDPO showed significantly (P < 0.05) hi gher growth rates compared with fish fed the other seven diets. No signific ant differences in growth performance or feed efficiency ratio were observe d between M. nemurus fed 9% CLO, CORN or CPO or fish fed diets containing 4 % CLO with either 5% CORN, SBO, CPO or RBDPO. Based upon these results, pal m oil-based diets can be used effectively for M. nemurus without compromisi ng growth or feed utilization efficiency. Muscle and liver fatty acid compo sition of M. nemurus reflected that of the dietary oils added in pelleted d iets fed to the fish. Considering the lower cost and availability of palm o il (compared with imported vegetable oils and fish oils) in many tropical c ountries, its use in dietary formulations for M. nemurus, and possibly othe r catfish species, will make these fish feeds less expensive.