Author
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Bosworth, Brian |
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Wolters, William |
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Submitted to: Journal of Applied Aquaculture
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/1/2004 Publication Date: 3/1/2005 Citation: Bosworth, B.G., Wolters, W.R. 2005. Effects of short-term feed restriction on production, processing, and body shape traits in market-weight channel catfish, ictalurus punctatus. (Rafinesque). Aquaculture Research 36:344-351. Interpretive Summary: Restricted feeding of farm-raised catfish is sometimes used during periods of low fish prices and high feed prices or to reduce the incidence of disease. Restricting feeding reduces growth but the effects of restricted feeding on catfish meat yield are not known. Market weight channel catfish were subjected to a 4-week period of restricted feeding to determine the effects on growth, survival, and meat yield. Growth was slower in feed-restricted fish as expected, but there was no effect of feed restriction on survival. Feeding status had no effect on carcass yield (weight of headless, eviscerated carcass relative to whole weight), but feed-restricted fish had lower boneless fillet yield (ratio of fillet weight to whole weight) than fish fed to satiation. Processors could minimize losses in meat yield due to processing fish from feed restricted environments as carcasses or steaks since yield of these product forms appears to be less affected than fillet yield by feed restriction. Technical Abstract: Effects of feed restriction on channel catfish production, processing, and body shape traits were determined. Channel catfish (mean weight = 0.77 kg) were stocked in 0.04 ha ponds and assigned to three feeding regimes: fed daily to satiation, fed once weekly to satiation, and not fed for a 4-week trial (2 ponds per regime). Fish were measured for processing yield and visceral composition after 2 and 4 weeks, and for body shape after 4 weeks. Growth was fastest in fish fed daily, intermediate in fish fed weekly, and slowest in unfed fish. There were no differences in survival among feeding regimes. Fish fed daily had thicker bodies and smaller heads than fish that were not fed and fish fed once weekly were intermediate. Carcass yield was higher for females than males and higher at week 2 than at week 4, but was not affected by feeding regime. Total fillet and shank fillet yield were higher in females than males, higher at week 2 than at week 4, and higher for fish fed daily than for feed restricted fish (fed once weekly and not fed). Visceral fat and liver yield were higher at week 2 than at week 4, and highest for fish fed daily, intermediate for fish fed weekly, and lowest for unfed fish. Short-term feed restriction had negative impacts on growth and meat yield. Processors could minimize yield losses by selling fish from feed restricted environments as carcasses or steaks since yield of these product forms appears to be less affected than fillet yield by feed restriction. |
