Nilo tilapia (Oreochromis niloticus) performance in different population densities

Abstract

The objectives of this study were to evaluate the zootechnical indexes (standard length, body width and weight) of Nile tilapia fingerlings (Oreochromis niloticus), of the Aquabel Premium strain, at different stocking densities T1 (250 fish/m3), T2 (500 fish/m3); T3 and T4 (1000 fish/m3) from day zero to 14 and, after, stocking with T3 (250 fish/m3) and T4 with (500 fish/m3) all using artificial aeration. The use of high stocking densities in tilapia culture is a possibility. In intensive systems, the objective is to maximize the use of water, increase productivity and profitability. However, high density is a factor that can be harmful because as it can cause biochemical and physiological alterations in animals. The changes are reflect in the behavior, aggressiveness is evident there is competition for food and territory, this eventually leads to decreased performance and weight loss, the high rates of nitrogenous excreta in the environment cause a decrease water quality. All these associated factors directly affect the growth potential and the welfare of the animals, reflecting in economic losses. While overcrowding triggers high mortality rates, low stocking rates bring economic losses. The experiment was carried out at the São Paulo Agribusiness Technology Agency, located in the city of Presidente Prudente/SP, and had as experimental design different population densities (T1, T2, T3, T4), with two repetitions each treatment. The tilapias were randomly distributed in 08 tanks, with artificial aeration and water recirculation, with unit volume of 250 liters. Oxygen and temperature were measured daily, the hydrogen potential was cheked weekly, and the filters were cleaned 03 times a week. All fingerlings were fed the same commercial feed containing 32% protein, offered until satiation (ad libitum). To evaluate the development of the animals, biometrics were performed at the beginning of the experiment, at 14 and 30 days. According to the results for body weight, there was a statistically significant difference for treatment 1 (T1), which was superior to the other treatments (T2, T3 and T4) at 14 and 30 days of the experiment.