Diet containing 35% crude protein improves energy balance, growth, and feed conversion in the Amazon river prawn, Macrobrachium amazonicum

Abstract

A technological package has been developed in South America for culturing prawn Macrobrachium amazonicum; however, little information is available on its physiology and diet. We investigated the effect of different protein levels in the diet (32%, 35%, and 38% crude protein -P) on the feed conversion rate (FCR), hepatosomatic index (HSI), and energy balance, calculated through the energy ingested and channeled toward growth, metabolism, feces, excretion, and exuviae for 30 days. Animals fed with 35% P channeled more energy toward growth (8.6% of energy intake), defecated less (only 5% of food intake), and improved FCR (about 1.2), and accumulated more energy in the body. In contrast, animals fed with 32% P channeled more energy into feces (36% of energy intake), and those fed with 38% P had the worst FCR and HSI. Regardless of the diet, ingested energy was mainly channeled toward metabolism (63–91%). Thus, we conclude that the protein content affects the variables evaluated and that the diet containing 35% P is a good alternative to optimize the use of energy channeled toward growth and minimize energy loss via excretion.