Growth, feed efficiency and body composition of second- and third-year channel catfish fed various concentrations of dietary protein to satiety in production ponds

摘要: Abstract Two pond-feeding experiments were conducted with channel catfish ( Ictalurus punctatus ), one for second-year fish and the other third-year fish, in which 400-m 2 earthen ponds fed five practical-type diets that contained 24, 28, 32, 36 or 40% crude protein. The similar to those used commercially, major ingredients being soybean meal, grain products, vitamin mineral supplements. Protein concentration of was increased by substituting a fixed ratio meal (5 : 1) corn. Energy not regulated. All adequate essential amino acids on percentage-of-protein basis. In experiment 1, from an average size 20 g 488 (151 days) at stocking density 13 590 per ha 594 1632 (141 4942 ha. Each diet four replicate ponds, once daily satiation through growing seasons. Increasing dietary protein had no significant effect weight gain negative linear fish. feed consumption Weight positively correlated both groups conversion significantly affected concentration. Efficiency utilization decreased linearly as increased. Dressing percentage 24 36% but dressing thirdyear muscle fat linearly, while moisture increased, Second-year lower conversion, less than results indicate second- highly intensive cultures will maximally feeds containing more approximately 24% satiate feeding, although content be higher (of only) low-protein diet. have advantages over efficiency fat, disadvantage yield.