Orégano em dietas para tilápia nilótica (Oreochromis niloticus)

Abstract

The use of feed additives capable of improve animal performance and is a tool of great interest for animal nutrition. The aim of this study was to evaluate the ability of growth promotion by the inclusion of dry leaves of oregano. 280 male juvenile nile tilapia (Oreochromis niloticus) were used with an initial average weight of 98.75 ± 8.83 g, housed in 28 tanks each with a capacity of 100L for 40 days, consuming increasing levels of oregano (0, 0.025, 0.050, 0.075, 0.100, 0.125 and 0.150%) in the diet. Were evaluated weight gain, feed intake and feed. The digestibility of protein, energy and ether extract were determined by the indirect method with chromic oxide as an inert indicator. Blood was collected from animals for glucose, hematocrit and total protein evaluation. For the morphometric analysis of the intestinal mucosa were collected fragments of approximately 5 cm length of the initial portion of the intestine. Statistical analyzes were performed with the aid of the program SAEG - Analysis System Statistics and Genetics (UFV, 1997) and the treatment means were subjected to regression studies. According to the equations, it was estimated that the inclusions of 0.043, 0.051 or 0.039% can improve by 0.21, 1.04 and 0.52% the digestibility of dry matter, organic matter and energy, respectively. For the other variables no significant effects were observed, allowing to conclude that the evaluated levels of oregano inclusion did not presented any change in animals health.