ABSTRACT The survival of several fish species in captivity depends on their adaptation to the environmental conditions and the biological characteristics. The objective of the study was to evaluate the influence of different light intensity levels in growth, behavior and skin pigmentation in juvenile of Lophiosilurus alexandri. Fishes were exposed to the following luminosities: 0, 218, 278, and 459 lux. The experiment was conducted for 75 days, in a water recirculation system with controlled temperatures and aeration. Catfish juvenile were distributed in 35 L aquariums, at the density of 0.28 ind L-1. In order to evaluate fish growth, weight, standard- total length, weight gain, food consumption, food conversion, biomass, specific growth rate and survival were measured twice times a month. Also, swimming behavior, skin pigmentation and plasma cortisol levels were evaluated. Light influences L. alexandri feed consumption, food conversion, behavior and plasma cortisol levels. Environments with low light are recommended for the L. alexandri growth.

Abstract: This study aimed to evaluate the effect of the commercial probiotic (Saccharomyces cerevisiae), antibiotic (florfenicol), and its combination for Nile tilapia culture. The experiment was arranged in a completely randomized design with five replications, and five treatments diets: Control: water and diet without additives; YD: yeast in the diet (1 g Kg-1); AW: antibiotic in the water (0.002 g L-1); AWYD: antibiotic in the water, and yeast in the diet (0.002 g L-1 and 1 g Kg-1); and AD: antibiotic in the diet (0.01 g kg-1). The growth parameters as total and standard length, weight, weight gain, biomass, Fulton’s condition factor, specific growth rate and plasma cortisol of tilapia did not show the difference between the treatments. The survival rates and food conversion rate of fish were greater in treatment with florfenicol included in the diet. The commercial probiotic did not improve growth or survival. The administration of the antibiotic florfenicol in the water needs more studies. The inclusion of the antibiotic in the diet promotes growth and survival in Nile tilapia juvenile.

A Vancomicina (VCM) é indicada no combate à infecções por Gram-positivas, porém não é considerada um agente de primeira escolha por causa dos seus efeitos adversos. Acredita-se que o estresse oxidativo é o principal mecanismo responsável pela lesão endotelial e consequente toxicidade da VCM, que varia desde flebites à nefrotoxicidade. Ademais, as recomendações de doses, diluições, taxas e tipos de infusão ainda são controversos. O objetivo deste trabalho foi determinar o efeito de diferentes diluições de VCM na lesão endotelial, hepática e renal utilizando parâmetros bioquímicos e análise histopatológica. Ratos Wistar foram divididos aleatoriamente em seis grupos e submetidos à canulação da veia femoral para a administração de medicamentos. Os grupos controle receberam 0,9 ml de salina e os outros receberam VCM (10mg/Kg/dia) nas diluições de 5.0 e 10.0 mg/ml durante 3 e 7 dias. Homocisteína, PCR-us, AST, ALT, GGT, ureia, creatinina, licopeno, alfa-tocoferol, beta-caroteno e retinol foram analisados. Fragmentos de rins, fígado e veia femoral canulada foram coletados. Este estudo mostrou alterações na ALT, caracterizando hepatotoxicidade. Entretanto, as diluições dos medicamentos não foram capazes de evidenciar alterações nos outros parâmetros bioquímicos. Por outro lado, alterações histopatológicas foram observadas nos rins e endotélio. Mais estudos são necessários para a caracterização do efeito da VCM quanto à toxicidade nos rins e endotélio e ainda na busca de marcadores bioquímicos capazes de evidenciar tais alterações morfológicas.

Vancomycin (VCM) is indicated in combat against Gram-positive infections, but it is not considered a first-choice drug because of its adverse effects. It is believed that oxidative stress is the primary mechanism of endothelial injury and the consequent VCM toxicity, which varies from phlebitis to nephrotoxicity. Moreover, dose recommendations, dilution, rates and types of infusion are still controversial. The aim of this study was to determine the effect of different VCM dilutions in endothelial, liver and kidney injuries by biochemical parameters and histopathological analysis. Wistar rats were randomly divided into six groups and subjected to femoral vein cannulation for drug administration. Control groups received 0.9 ml of saline and the others received VCM (10mg/Kg/day) at dilutions of 5.0 and 10.0 mg/mL for 3 and 7 days. Homocysteine, hs-CRP, AST, ALT, GGT, urea, creatinine, lycopene, alpha-tocopherol, beta-carotene and retinol were analyzed. Kidney, liver and cannulated femoral vein fragments were collected.This study showed alterations in ALT which featured hepatotoxicity. However, drug dilutions were not able to show changes in other biochemical parameters. In contrast, kidney and endothelium pathological changes were observed. More studies are needed to characterize VCM induced kidney and endothelium toxicity and biochemical markers able to show such morphological modifications.