Feather meals and meat and bone meals from different origins as protein sources in rainbow trout (Oncorhynchus mykiss) diets

Two feeding trials were conducted to evaluate the potential of feather meal and meat and bone meal as protein sources in rainbow trout diets and as well as to compare the nutritive value of ingredients from different origins. Three feather meals were used in a 20-week trial with fish reared at 8.5 degrees C. The feather meals, alone or in combination with corn gluten meal and blood meal (steam-tube dried), replaced herring meal in diets formulated to be isoproteic (ca. 47% digestible protein (DP)) and isoenergetic (ca. 22 MJ/kg digestible energy (DE)) assuming apparent digestibility coefficient (ADC) values for protein and energy of 75% for the three feather meals. Three meat and bone meals were used in a 12-week trial with fish reared at 15 degrees C. Increasing levels of meat and bone meal replaced herring meal in diets formulated to be isoproteic (ca. 43% DP) and isoenergetic (ca. 19 MJ/kg DE) based on ADC for protein of 85% and ADC for energy of 70% for the three meat and bone meals. The incorporation of up to 15% feather meal (providing about 20% of total DP) in the diet was possible without affecting growth, feed efficiency, nitrogen or energy gains of the fish. The incorporation of up to 24% meat and bone meals (providing about 25% of total DP) in the diet was possible without affecting growth but resulted in a small yet significant reduction in feed efficiency compared to control diet. No significant differences were observed among feather meals and meat and bone meals from various origins. The results from this study show that feather meal and meat and bone meal have good potential for use in rainbow trout diets. (C) 2000 Elsevier Science B.V. All rights reserved.