Evaluation of low-protein alternative diets for pond-raised hybrid catfish, Ictalurus puncatus X Ictalurus furcatus

Authors: LI, MENGHE - Mississippi State University; ROBINSON, EDWIN - Mississippi State University; LUCAS, PENELOPE - Mississippi State University; Bosworth, Brian

Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2014
Publication Date: 4/2/2015
Citation: Li, M.H., Robinson, E.H., Lucas, P.M., Bosworth, B.G. 2015. Evaluation of low-protein alternative diets for pond-raised hybrid catfish, Ictalurus puncatus X Ictalurus furcatus. Journal of the World Aquaculture Society. 46:228-234.

Interpretive Summary: Previous research has shown there were no significant differences in weight gain and feed efficiency among hybrid catfish fed diets with protein levels ranging from 28 to 36%. Since the price of catfish food fish diets has reached nearly US $600/ton due to dramatic increases in prices of soybean meal and corn in the past few years, there is interest in evaluating low-protein diets for pond-raised hybrid catfish. It is not clear how much soybean meal can be replaced with less expensive alternative feedstuffs in lower protein, hybrid catfish diets. Therefore, this study was conducted to compare 24% protein, traditional and alternative diets containing various soybean meal levels with a 28% protein control diet for pond-raised hybrid catfish. Results show pond-raised hybrid catfish can be fed a 24% protein diet with 20% soybean meal from large fingerlings to market size without significantly affecting net yield, weight gain, feed conversion ratio, survival, and fillet proximate composition. However, fish fed 24% protein diets had reduced carcass and fillet yield compared with fish fed the 28% protein control diet. At moderate feed prices a 28% protein diet with ingredient composition similar to the one used in this study should be used to ensure optimum fish growth, feed efficiency, and processing characteristic of hybrid catfish. However, a 24% protein alternative diet with 20% soybean meal may be substituted for 28% protein diets for production of food-sized hybrid catfish, for example, when feed prices are high or when market-size fish must be maintained for extended periods before harvest.

Technical Abstract: A study was conducted to evaluate low-protein traditional or alternative diets for pond-raised hybrid catfish, Ictalurus punctatus × Ictalurus furcatus. Three 24% protein diets containing decreasing levels of soybean meal (30, 20, and 15%) and increasing levels of cottonseed meal and corn germ meal were compared with a 28% protein control diet. Hybrid catfish fingerlings (mean initial weight = 71 g/fish) were stocked into 20 earthen ponds (0.04 ha) at a density of 14,826 fish/ha with five ponds per dietary treatment. Fish were fed once daily to apparent satiation for a 191-day growing season. There were no significant differences in total diet fed, net yield, weight gain, feed conversion ratio (FCR), survival, or fillet proximate nutrient composition among dietary treatments (P = 0.10). However, regression analysis showed for fish fed 24% protein diets there was a linear increase in FCR as soybean meal levels decreased (P = 0.06). Compared with fish fed the 28% protein control diet, fish fed 24% protein diets had lower carcass and fillet yield. Results demonstrate a 24% protein alternative diet containing 20% soybean meal may be substituted for 28% protein diets for hybrid catfish during food fish production.