Influência dos horários de fornecimento de dietas na atratividade e palatabilidade para o dourado (Salminus brasiliensis) e para a tilápia do Nilo (Oreochromis niloticus)

Abstract

This work was conducted with the objective of analyzing parameters related to the attractiveness and palatability of feed for dorado (Salminus brasiliensis) and Nile tilapia (Oreochromis niloticus) in relation to the feeding times, to investigate whether the schedules can influence these parameters. In this way, two works of research were carried out. In each one, quantitative data from the two experiments on the attractiveness and palatability were analyzed, observing the following parameters: time to capture the first pellet, number of rejections after capturing the pellet, number of approaches without pellet capture, number of pellets consumed, time taken for total consumption and API (attractiveness and palatability index). Thus, the parameters of each experiment were separated by time, and statistical analyses were performed. In the first research, the fish were placed individually in aquariums and were fed six times a day (8 am, 10 am, 12 pm, 2 pm, 4 pm and 6 pm) with different diet compositions (tested in comparison to a control diet). The results showed significant differences between the diets tested: in the first experiment, at 8 am, 12 pm, 4 pm and 6 pm, in parameters such as number of rejections after pellet capture, number of pellets consumed, time spent for total consumption and API; and in the second experiment, at 8 am, 10 am, 12 pm, 2 pm and 6 pm, the parameters were number of pellets consumed, time taken for total consumption and API. Therefore, in this first research, it was verified that the times of supplying diets to the dorado can influence parameters of attractiveness and palatability. On the other hand, in the second research carried, in the case of Nile tilapia, quantitative data from two experiments with the species were analyzed, in which the fish were distributed individually in aquariums and were fed with different feeding frequencies (an experiment at 8am, 10:30 am, 1 pm, 3:30 pm and 6 pm; and the other experiment at 8 am, 10 am, 12 pm, 2 pm, 4 pm and 6 pm) and different feed compositions (with different substances tested as possible substitutes for fishmeal). The results of this research with Nile tilapia showed the following statistical effects between the tested diets: in the first experiment, at 10:30 am, 3:30 pm and 6 pm, in parameters such as the number of pellets consumed and time spent for total consumption; in the second experiment, at 10 am and 4 pm, respectively in the parameters time spent for total consumption and number of approaches without pellet capture. Therefore, this second research concluded that feed supply times for Nile tilapia can influence certain parameters of attractiveness and palatability. In view of both research carried out, with dorado and Nile tilapia, it appears that the times of offering food to these species influence parameters of attractiveness and palatability.