Depletion study and estimation of the withdrawal period for enrofloxacin in pacu (Piaractus mesopotamicus).

Defining the pharmacokinetic parameters and depletion intervals for antimicrobials used in fish will help in the development of important guidelines for future regulations by Brazilian agencies on the use of these substances in fish farming. This paper presents a depletion study for enrofloxacin (ENR) and its main metabolite, ciprofloxacin (CIP), in pacu (Piaractus mesopotamicus) fillets. The depletion study was carried out under monitored environmental conditions, with the temperature controlled at 27 °C to mimic the fish farming conditions in Brazil. ENR was administered orally via medicated feed for 10 consecutive days at daily dosages of 10 mg/kg body weight (b.w.). The fish were slaughtered at 6, 12, and 24 h and 2, 3, 5, 8, 12, 17, and 24 days after the medication period. Considering a maximum residue limit of 100 µg/kg for the sum of the ENR and CIP residues in the fillet, the results obtained in the depletion study allowed the estimation of a half-life for ENR of 2.75 days and a withdrawal period of 23 days. The results obtained in this study are important for the farming of pacu in tropical regions.

Produção, caracterização e avaliação biológica de silagens de resíduos de camarão para tilápia-do-nilo / Production, characterization and biological evaluation of shrimp waste silage for Nile tilapia

Elaboraram-se e caracterizaram-se nutricionalmente dois tipos de silagens fermentadas de resíduos de camarão-sete-barbas (Xiphopenaeus kroyeri), alterando-se as fontes de carboidratos. As silagens foram formuladas com resíduo de camarão, 15 por cento de carboidrato -melaço de cana-de-açúcar (SM) ou varredura da farinha láctea (SF)-, 10 por cento de iogurte, 0,25 por cento de ácido sórbico e 1 por cento de ácido fórmico. Cada silagem foi caracterizada durante a estocagem, por 120 dias, quanto à composição centesimal, nitrogênio não protéico e todas comparadas por meio do teste de digestibilidade in vivo com juvenis de tilápia-do-nilo. Após o 30º dia de estocagem, observou-se que a SM apresentou maior (P<0,05) teor de cinzas (SM= 34,97g.100g-1 e SF= 30,92g.100g-1) e menor teor de matéria seca (SM= 20,02g.100g-1 e SF= 21,11g.100g-1). Os coeficientes de digestibilidade aparente (CDA) e a proteína digestível não diferiram entre os tratamentos (P>0,05), mas observou-se alta digestibilidade nas dietas (CDA SM= 78,2 por cento e CDA SF= 73,1 por cento). Independente da fonte de carboidrato, as silagens elaboradas com resíduos de camarão-sete-barbas mantiveram-se estáveis durante 120 dias e podem ser utilizadas como ingrediente de rações para a tilápia-do-nilo

Two types of fermented shrimp waste silage (Xiphopenaeus kroyeri) were elaborated and characterized, alternating the sources of carbohydrates. The silages were elaborated with shrimp waste, 15 percent of carbohydrate - sugar cane molasses (SM) or "Farine Lactée" (SF) -, 10 percent of yogurt, 0.25 percent of sorbic acid, and 1 percent of formic acid. Each silage was characterized during storage for 120 days on proximate composition and non protein nitrogen, besides nutritionally compared by digestibility trials to Nile tilapia juveniles. After the 30th storage day, it was observed that SM presented higher ashes content (SM= 34.97g.100g-1 and SF= 30.92g.100g-1) and lower dry matter content (SM= 20.02g.100g-1, SF= 21.11g.100g-1). The apparent digestibility (ADC) and digestible protein coefficients did not vary between trials (P>0.05), but higher digestibility in the diets (ADC SM= 78.2 percent, ADC SF= 73.1 percent) was observed. No matter which carbohydrate source used, silage made from shrimp waste remained stable for 120 days and may be used in diets to Nile tilapia