Níveis de extrato de orégano e proteína em dietas para tilápia nilótica (Oreochromis niloticus)

Abstract

The aim of the study was to assess how the protein inclusion in the diet can improve the growth promoting effect of oregano extract to juvenile tilapia (Oreochromis niloticus). 360 juvenile males of Nilotic tilapia (Oreochromis niloticus) were used, with initial average weight of 36,80 ± 11,85g, kept in 30 tanks with a capacity of 100L each, for 60 days. The animals were randomly distributed in the tanks, consisting 12 animals. At the end of the experiment, four animals of each unit had blood collected by cardiac puncture. Of each slaughtered animal was collected a gut sample to morphometric analysis. The animals were gutted and packed in plastic containers for later determination of dry matter, ash, crude protein, gross energy and ether extract. The group fed 33% CP and 2,5% oregano had the highest values for average weight gain and weight gain. For hepatosomatic, treatments containing 1,5% and 2,0% different from each other, and the group with 30% CP had higher values. The diet with addition of 33% protein does not adversely alter the performance parameters of hematology and animals besides animal body parameters are unchanged and appropriate for the species. The best percentage of oregano used was 2,5%, having improved the weight gain of the animals.