Juliano Uczay

Farinha de minhoca em dietas para juvenis de jundiá

One of the greatest demands, concerning native fish nutrition, is the evaluation of alternative protein sources that can be used in diets. This study aimed at evaluating the growth rate and body composition of jundia juveniles fed with different levels of earthworm meal. A total of 300 fish, with an average initial weight of 15.6 g ± 5.65 g, were distributed in 15 polypropylene tanks (250 L), for 30 days. A completely randomized design with five treatments (10%, 20%, 30% and 40% of earthworm meal inclusion and a control treatment) and three replications, totaling 20 fish per experimental unit, was used. The fish were fed twice a day, getting 5% of their body weight in feed day -1 . At the end of the experimental period, the final weight, total and standard length, specific growth rate, condition factor and relative weight gain were evaluated. The body composition was also analyzed, being determined the rates of moisture, ashes and body fat and protein, as well as blood glucose. The weight and total and standard length were not influenced by the addition of earthworm meal to the diet. The inclusion levels of earthworm meal affected the fish specific growth rate, relative weight gain and condition factor. The earthworm meal can be added up to 30%, in jundia juveniles diets, without compromising fish growth .

Utilização de óleos vegetais em dietas para juvenis de piava (Leporinus obtusidens)

This study aimed to evaluate the response of piava (Leporinus obtusidens) after the use of vegetable oils in the diet, under performance, nutrient deposition and activity of digestive enzymes. Over 35 days five treatments were tested, with the inclusion of 3% of corn oil, soy, canola, linseed, and a control treatment without the inclusion of oil. Fish with an average initial weight of 1.78±0.07 g were randomly assigned in a water recirculation system consisting of 15 tanks, with suitable water quality parameters throughout the trial period. At the end of biometrics experiment data was collected. The experimental design was completely randomized, with five treatments and three replicates; the data was submitted to normality test and analysis of variance. The averages, when significant, were compared by Tukey test (p<0.05). Fish fed diets containing canola oil showed higher weight and length and protein deposition when compared to the control treatment. Higher chymotrypsin activity was observed in the fish fed the diet containing soya oil and lower with linseed oil. It is concluded that the use of oils in the diet is essential for best performance of the fish, and canola oil as indicated by optimizing the deposition of body protein for animals.

Produtos anestésicos para juvenis de carpa húngara ("Cyprinus carpio")

In the aquaculture procedures, the fishes are easily stressed in differetn rearing phases. So, is important the use of anesthetics for to prevent physical injuries and promote metabolism decrease, resulting in improved welfare for fish. The aim of this study was analyze the anesthetical induction of Hungarian carp fingerlings (Cyprinus Carpio) displayed of the different dosages of eugenol (20, 30, 40 and 50mg/L), ketamine (300, 600, 900 and 1200mg/L), xylazine (800, 1100, 2000mg/L) and the ketamine/xylazine association (300/300, 600/600, 900/900 and 1200/1200mg/L). Each dosage was tested for ten fish, individually subjected to the anesthetic bath with container containing 1 liter of water. All experimental procedures were the same as in the tests. After, it was analyzed the anesthetic time (TA) and the recovery time (TR). The anesthetics eugenol, ketamine and the ketamine/xylazine association allowed the deep anesthesia, but xilazine didn’t allow it. Among the anesthetics tested, eugenol at 50mg/L demonstrated better anesthetic induction and recovery time for carp juveniles.

Diet selenium improves the antioxidant defense system of juveniles Nile tilapia ( Oreochromis niloticus L.)

From the advancement of tilapia production in recent years, diets are sought that allow the maximum growth, improving health and fish quality. In this study growth, biochemical, hematological and oxidative parameters were evaluated of tilapia fed with increasing selenium levels: 0.53, 0.86, 1.04 and 1.22 mg kg-1. It was used 400 juveniles (initial weight = 36.51 ± 10.88 g), fed for six weeks. There was no effect of selenium on fish growth, biochemical and hematological parameters. In the oxidative parameters, there was an increase in non-protein thiols and a decrease in malondialdehyde levels, evidencing antioxidant effects of selenium. The diet selenium levels above 0.86 mg kg-1 improved the antioxidant system and does not affect to biochemical, hematological and growth parameters of tilapia juveniles.