Production characteristics of pond-raised channel catfish Ictalurus punctatus fed diets with and without animal protein for three growing seasons.

摘要

An experiment was conducted to determine the long-term effects of an all-plant protein diet on production characteristics (harvest yield, dressing percentage and body composition) of catfish, I. punctatus, taken from top-harvested, multiple-stockedponds over a 2.5-year period of continuous production. Fish in eight 0.08-ha ponds were fed an extruded, 32% protein control diet (CON) containing animal and plant proteins, while fish in 8 replicate ponds were fed an isonitrogenous diet containing onlyplant proteins, primarily from cottonseed meal and soyabean meal (APP). Diets were fed once daily to apparent satiation during the growing season. Ponds were top-harvested twice per year in the spring and autumn and partially restocked after each harvest. CON-fed fish received 13 335 kg of feed during the 2.5-year period. APP-fed fish received 13 506 kg of feed. Total yields were 5562 kg of CON-fed fish and 5840 kg of APP-fed fish while average annual yields were 3477 kg/ha and 3650 kg/ha, respectively.Feed conversion ratios, 2.5 for CON-fed fish and 2.6 for APP-fed fish, did not differ. Liveweights at harvest averaged 529 (CON) and 481 g (APP), and were not significantly different. Dressing percentages were 59% for fish fed both diets. APP-fed fish had less (P<0.05) visceral fat and less (P<0.05) muscle lipid than CON-fed fish. Results indicate that a lysine-supplemented, all-plant protein diet containing 40% cottonseed meal and 20% soyabean meal is suitable for long-term production of channel catfish in earthen ponds and such a diet can reduce the fat content of pond-reared fish.