Effects of no feeding, maintenance feeding, and refeeding on production and processing characteristics of market-size hybrid catfish

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

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2016
Publication Date: 6/15/2016
Citation: Menghe, L.H., Wise, D.J., Bosworth, B.G., Lucas, P.M., Kingery, K. 2016. Effects of no feeding, maintenance feeding, and refeeding on production and processing characteristics of market-size hybrid catfish. North American Journal of Aquaculture. 78:(3)224-228.

Interpretive Summary: n commercial catfish production, harvest delays can occur for various reasons (off-flavor, oversupply of fish, or low fish prices). Delays in harvest increase risk of fish mortalities and restrict cash flow resulting in diminished profits for farmers. In addition, fish larger than optimal harvest size convert feed less efficiently and decrease in value because they are too large for routine processing. Issues with harvest delays are accentuated in hybrid catfish (female channel catfish × male blue catfish) because of their very aggressive feeding and rapid growth. Development of feeding strategies to maintain body weight of market-size hybrid catfish is needed to minimize economic losses associated with harvest delays. A pond study was conducted to examine effects of no feeding, maintenance feeding (feeding once weekly), and refeeding on production and processing characteristics of market-size hybrid catfish. Fish were either not fed, fed once weekly or fed to satiation once daily for two months; and then fish in half the ponds were harvested, measured for total weight and processing traits. All fish in the remaining ponds were then fed daily to satiation for an additional month. Fish not fed for two months had a 14.3% weight loss and fish fed once per week had a 6.7% weight gain. Fish not fed and fed once per week both had reduced visceral fat and fillet yield compared with fish fed daily. After one month of daily feeding following feed restriction, fish previously not feed and fed once per week had the same weight gain, fat levels and fillet yield. Fish fed daily throughout the trial had significantly higher visceral fat and marginally higher fillet yield than both feed restricted groups at the end of the study. Feeding once weekly to maintain body weight, followed by a month of re-feeding seems to be the best strategy to prevent fish from becoming to large and alleviate reductions in carcass yield due to feed restriction.

Technical Abstract: A pond study was initiated to evaluate effects of no feeding, maintenance feeding, and refeeding on production and processing characteristics of market-size hybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus). Fish with an average weight of 644 g were stocked into 20 earthen ponds (0.04 ha) at 14,826 fish/ha at the end of May. They were either not fed (N2), fed once weekly (W2) to satiation for 2 months to simulate a longterm harvest delay, or fed daily (D2) to satiation. After 2 months fish in half the ponds in each of the two feedrestricted treatments were harvested, and all fish in the remaining ponds were fed daily for an additional month. After 2 months N2 fish experienced a 14.3% weight loss compared with a weight gain of 6.7% for FW2 fish. After 2 months both N2 and W2 fish had reduced visceral fat and fillet yield compared with fish fed daily, but there were no significant differences in visceral fat percentage and fillet yield between N2 and W2 fish. At the end of 3 months, there were no significant differences in weight gain, net yield, fillet yield, or visceral fat whether fish were previously not fed or fed once weekly for the first 2 months, but fish fed daily throughout had significantly higher visceral fat and marginally higher fillet yield. Feeding once weekly for 2 months followed by 1-month full feeding resulted in significantly higher feed conversion ratio than fish fed daily for 3 months. Results demonstrate feeding once weekly can generally maintain body weight of hybrid catfish. No feeding or feeding once weekly for 2 months does not affect survival but significantly reduces fillet yield. One month of full feeding following no feeding or maintenance feeding improves fillet yield relative to values before refeeding.