Efficacy of crystalline lysine in alternative diets for pond-raised hybrid catfish, female Ictalurus punctatus X male Ictalurus furcatus

Authors: MENGHE, LI - Mississippi State University; LUCAS, PENELOPE - Mississippi State University; KINGERY, K - Mississippi State University; Bosworth, Brian

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2015
Publication Date: 4/25/2016
Citation: Menghe, L.H., Lucas, P.M., Kingery, K., Bosworth, B.G. 2016. Efficacy of crystalline lysine in alternative diets for pond-raised hybrid catfish, female Ictalurus punctatus X male Ictalurus furcatus. North American Journal of Aquaculture. 47(4):519-525.

Interpretive Summary: Lysine is generally considered to be a limiting amino acid in diets for most farmed fish. In the past catfish diet formulations contained enough soybean meal to meet the lysine requirement. However, increases in the price of soybean meal have resulted in decreases in soybean meal and increases in corn-based products in recent catfish diets. Because corn is low in lysine, supplemental lysine is added to these new diet formulations to meet the requirement. The source of supplemental lysine can effect its absorption and availability to the fish, therefore it is necessary to know how the source of lysine effects the level of supplementation needed. In this study we compared production and processing traits of hybrid catfish (channel catfish female x blue catfish male F1 hybrid) fed traditional diets with adequate lysine to new diets supplemented with crystalline lysine at two levels. There were no differences in growth, survival, meat yield or body composition of catfish of hybrid catfish fed the different diets. Results from this study show that crystalline lysine can be considered 100% available when used to supplement lysine-deficient diets for pond-raised hybrid catfish. This information is important to catfish feed mill operators and farmers in evaluating diet formulations and effects of production and profitability.

Technical Abstract: study was conducted to examine the efficacy of crystalline lysine in alternative diets for pond-raised hybrid catfish, ' Ictalurus punctatus × ' Ictalurus furcatus. Two 28% protein alternative diets supplemented with l-lysine HCl at the required level based on 62% (previously published value) or 100% lysine availability were compared with a traditional 28% protein control diet. Hybrid catfish fingerlings (mean initial weight = 43 g/fish) were stocked into 15 earthen ponds (0.04 ha) at a density of 14,826 fish/ha with five ponds per treatment. Fish were fed once daily to apparent satiation for a 173-d growing season. There were no significant differences in total diet fed, net yield, weight gain, and survival among dietary treatments. There were also no significant differences in carcass yield, fillet yield, and fillet proximate composition and fillet lysine concentration among treatments. Fish fed the traditional control diet had slightly, but significantly, lower feed conversion ratio than fish fed alternative diets, which is likely related to higher dietary fiber levels in the alternative diets. Results from this study show that crystalline lysine can be considered 100% available when used to supplement lysine-deficient diets for pond-raised hybrid catfish.