Partial substitution of soybean meal with animal protein sources in diets for channel catfish

Abstract

Nine-week laboratory feeding experiments were conducted to evaluate partial substitution of animal protein sources into a 32% protein soybean-meal-corn basal diet for channel catfish ( Ictalurus punctatus) fingerlings. In the first experiment, substitution of 5, 10, 20, and 40% menhaden fish meal into the basal diet resulted in increases in weight, protein, and fat gains as fish mean was increased to 20% ( P < 0.05), and an increase in fat gain as fish meal was increased to 40% ( P < 0.05). In the second experiment, the basal diet was supplemented with 5 and 10% fish meal or isonitrogenous amounts of protein from meat and bone meal (5.6 and 11.3%), blood meal (3.4 and 6.8%), and a 60:40 combination of meat and bone and blood meals (5 and 10%). Weight, protein, and fat gains were improved ( P < 0.10) when the lower level of each animal protein, except blood meal, was substituted into the basal diet. Increasing the dietary level of each animal protein, except blood meal, improved gains over those from diets containing the lower level of the animal protein ( P < 0.10). Fish meal improved gains more than isonitrogenous levels of the other animal proteins at both dietary levels ( P < 0.10). Estimated amino-acid contents of the diets indicate that the increase in growth produced by including fish meal may be explained on the basis of increasing dietary levels of the most limiting amino acids; however, the increase in growth effected by including the other animal protein sources in the diet cannot be explained on that basis. Food consumption during the first 3 days of experiment indicated that inclusion of fish meal, meat and bone meal, or the meat and bone-meal-blood-meal combination improved diet palatability.