Protein Nutrition in Fish-V

Abstract

The mode of utilization of absorbed nitrogen for maintenance, growth and waste energy was investigated on the basis of the previous study on the biological values of various pro-teins. The results obtained are summarized as follows: 1. The biological value of dietary proteins exerts a remarkable influence upon the mode of utilization of absorbed nitrogen for maintenance, growth and energy. 2. Dietary protein is most effectively utilized for growth at near 100mg of absorbed nitrogen per 100g of weight per day. 3. The amount of nitrogen required for maximal retention of protein is found to be 190-220mg daily per 100g of weight when casein (biological value 80) is used. This nitrogen requirement varies according to the biological value of the dietary protein. 4. When casein is used as the sole nitrogen source for carp, the amounts of protein required for maintenance, maximal retention and optimal utilization are considered to be around 0.95g, 13g and 7g per 1kg of weight per day, respectively.