Produção de juvenis de tilápia-do-nilo (Oreochromis niloticus) em função de diferentes fontes de alimentação.

Abstract

In family production, the bottleneck for tilapia production in the Brazilian semiarid is the availability of feed purchases by producers. Thus, it is important for these producers to be able to produce rations with ingredients available in the region, in order to make production costs cheaper, either for subsistence or to increase family income. Therefore, the objective was to indicate a source of food alternative to commercial feed, which is economically viable, and which does not intervene in the zootechnical performance of the fry. Thus, three 50 m2 nurseries with a depth of 1.7 meters were used. These were previously drained and dried in the sun, with subsequent liming for their disinfection. Hydrated lime in the proportion of 200g m- 2 was used in the nurseries. Chemical fertilization was carried out in one of the nurseries using 0.715 kg of simple superphosphate and 0.250 kg of urea for the 50 m2, repeating the application of urea weekly. 300 Nile tilapia fingerlings were used, divided into 100 fingerlings per nursery, with L2, L3 and L4, with an average weight of 86.54g, 85.60g and 86.04g, respectively. Providing as feed, experimental diets with 36% and commercial diets with 32% CP provided four times a day (07:00, 10:00, 13:00 and 16:00 hours). The nursery with primary production from fertilization was fertilized weekly. The experimental feed was formulated according to the Brazilian Tables for Tilapia Nutrition, with 3042 kcal ED, 35% PB and 32% PD. The experimental feed the ingredients were ground into particles smaller than 0.7mm in diameter and homogenized. Subsequently, 40% distilled water at 55 ° C was added to the mixture. The mixture of ingredients was processed in a meat grinder to form the pellets. The feed was dehydrated in an air circulating oven at 55 ° C for 24 hours and finally stored in plastic bags. Physical standards of water quality were measured. The first biometry was carried out 30 days after the beginning of the experiment, with the subsequent biometrics performed every 14 days, taking a sample of 10 fish. At the end of the experiment, the fish were caught, counted and weighed, and weight gain and apparent feed conversion were evaluated. Information on the price of inputs was collected and an economic analysis was carried out between the two rations in the experiment. In possession of the data, they were subjected to ANOVA analysis of variance by the F Test at 1% probability, by the SAS statistical program (2011). The results obtained allowed to observe that the feeding of the fish only and exclusively through fertilization products is not enough for a good development of the fry. The commercial feed showed better weight gain and feed conversion, but the total cost and the cost per kilogram of feed are higher. Experimental feed is a good alternative to commercial feed, with similar weight gain until the 73rd day, and a lower total cost and cost per kilogram of feed.