Influence of Levels of Dietary Protein and Supplementary Copper on the Performance of Growing Rabbits

Abstract

Ninety-six six-week-old New Zealand White rabbits were fed a low protein diet (LP) containing 14% protein, a medium protein diet (MP) containing 18% protein or a high protein diet (HP) containing 22% protein. Each dietary protein treatment was further supplemented with either 0, 100, 150 or 200 parts/10 6 copper. The MP diet was superior to the LP or HP diet in promoting daily rate of growth and efficiency of feed utilization. Liver and kidney weights were increased ( P < 0.05) by the MP diet over the LP diet, but non-significantly over the HP diet. Stomach weight increased ( P < 0.05) and the caecum and small intestine were thickened as dietary protein level increased. Added copper improved rate of growth and carcass yield. The main result of copper on abdominal organs was a significant ( P < 0.05) thinning of the caecum. The experiment seems to indicate that as the level of dietary protein increases, the level of supplemental copper required to bring about a relative improvement in body gains reduces.