Location: Warmwater Aquaculture Research UnitTitle: Channel catfish Ictalurus punctatus size and feed conversion ratio Author
Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2009
Publication Date: 10/1/2010
Publication URL: http://handle.nal.usda.gov/10113/55536
Citation: Robinson, E.H., Li, M.H. 2010. Channel catfish Ictalurus punctatus size and feed conversion ratio. Journal of the World Aquaculture Society. 41:829-833. Interpretive Summary: Feed conversion ratio is a measure of how efficiently an animal converts feed to body mass. It is affected by many factors including fish size and strain, feeding rate, feed quality, and environmental factors. This study determined effects of fish size on feed conversion ratio of pond-raised channel catfish. Results demonstrate that smaller catfish consume more feed as a percentage of body weight, grow faster, and convert feed more efficiently than larger fish. Results suggest that it is more cost effective to grow relatively smaller market-size fish than larger fish especially when feed prices are high.
Technical Abstract: Channel catfish, Ictalurus punctatus, of five size-classes were stocked into 20, 0.04-ha earthen ponds at a rate of 14,826 fish/ha. Mean initial weights for each size-class were 0.232, 0.458, 0.678, 0.911, and 1.10 kg/fish. Four ponds were randomly allotted to each treatment. A commercial 28% protein diet was fed daily to apparent satiation. When fish reached a predetermined weight in each size-class, all fish were harvested, counted, weighed. Mean final weights for each size-class were 0.435, 0.683, 0.904, 1.16, and 1.36 kg/fish. The data show that smaller fish consumed more feed (as a percentage of body weight) and grew faster than larger fish. The data clearly demonstrate that feed conversion ratio and fish size are highly correlated and that feed conversion ratio increases as fish size increases. These data hold to the basic principle of animal husbandry that smaller animals are fast gainers and fast gain is generally the most efficient gain.