Use of mixed feeding schedules in fish culture: performance of common carp, Cyprinus carpio L., on plant and animal protein based diets

Abstract

A 90-day growth trial was conducted with common carp, Cyprinus carpio L., to test the suitability of mixed feeding using a plant-based low-protein diet (16% -diet A), and two fish-meal-based diets of 26% protein (diet B) and 31% protein (diet C). Three mixed feeding schedules were tested: 1A/2B, 2A/2B and 2A/2C; numerals refer to number of days each diet (A, B or C) was offered continuously. Fish fed diets A, B or C continuously served as controls. Fish grown on diet A grew the least, while there was no significant difference between those fed on diets B or C. Of the three mixed schedules, 2A/2C produced the highest growth, which was better than that on control diets B or C. Specific growth rate (%) and food conversion ratio and protein retention were found to be good for all mixed feeding schedules. The plant protein diet resulted in poor-quality flesh as indicated by carcass composition. The study supports the view that fish can be fed alternately with animal- and plant-protein-based diets of varied protein levels. This practice would help to reduce protein input, and would contribute to the efficient utilization of low-quality, plant-protein-based diets.