Estratégias de manejo alimentar para otimizar o uso de alimento em suspensão para tilápia do Nilo (Oreochromis niloticus) cultivada em bioflocos

Abstract

The development of technologies that allows use of nutrients by animals is very important for the economic and environmental aquaculture sustainability. The present study aimed to assess feeding strategies for tilapia juveniles in a biofloc system. This study evaluated water quality parameters and variables of performance, body composition and nutritional composition of the flocs. Nile tilapia juveniles weighing approximately 32 g were submitted to treatments with four frequencies (one, two, three and four times a day) and three feeding rates (100, 75 and 50% consumption in relation to visible satiety) in bioflocs (carbon source: sugarcane, C:N ratio: 6:1) for 56 days. With the exception of dissolved oxygen, protein retention rate and body protein content, the different feeding frequencies did not cause significant changes in the data on water quality, performance, survival, protein utilization, nutrient deposition, body composition and nutritional composition of the floc. The reduction in feed rate resulted in a lower performance, but promoted a decrease in the concentration of total ammoniacal nitrogen, solids, hepatosomatic index and body lipids. In addition, we found a better efficiency of protein utilization at 75% feed. The nutritional composition of the floc was not affected by the feed frequency, and the feed rate reduction from 100% to 75% did not significantly alter the protein content of the floc. In conclusion, the results showed that feeding once a day can be used for juveniles of Nile tilapia grown in bioflocs. Although the satiety rate has led to better performance, it may not be the best option for cultura in bioflocs, due to higher feed conversion and reduction of water quality (total solids and total ammoniacal nitrogen increase).