Effect of Dietary Total Protein and Animal Protein on Growth and Feed Efficiency of Juvenile Channel Catfish Ictalurus punctatus and Their Response to Edwardsiella ictaluri Challenge

A laboratory study was conducted to evaluate effects of dietary total protein and animal protein source and concentration on growth and feed efficiency of juvenile channel catfish Ictalurus punctutus and their response to Edwardsiellu ictuluri challenge. Eight diets evaluated were: three diets containing either 28, 32, or 36% crude protein with 6% menhaden fish meal and 6% meat and bonehlood meal and five diets containing 32% crude protein with either no animal protein, 68 or 12% menhaden fish meal, or 6% or 12% meat and bonehlood meal, respectively. Twenty channel catfish with an average weight of 6.6 g/fish were stocked into each of forty 110-L flow-through aquaria (five aquaridtreatment). Fish were fed to approximate satiation twice daily for 9 wk. Fish in each tank were then exposed to E. ictaluri . There were no differences in feed consumption, weight gain, feed efficiency, and survival before and after challenge among fish fed diets containing 28, 32, or 36% protein with 6% menhaden fish meal and 6% meat and bone/ blood meal. Fish fed a 32% all-plant protein diet had weight gain and feed efficiency similar to fish fed diets containing 12% menhaden fish meal, but had a higher weight gain than fish fed a 32% protein diet containing 6% meat and bonehlood meal. No significant differences were observed in survival after E. ictuluri challenge among fish fed diets containing the various levels of animal proteins. Results indicate that dietary protein levels varying from 28% to 36% do not appear to affect growth, feed efficiency. and E. icraluri resistance or susceptibility in fingerling channel cattish fed to satiation and raised from approximately 7 to 56 g under laboratory conditions. Data also demonstrate that a 32% all-plant protein diet can be fed to small fingerling channel catfish without adversely affecting growth, feed efficiency, or resistance to E. ictuluri .