ABSTRACT. Oreochromis niloticus (Nile tilapia) is one of the most produced fish for human consumption globally; however, these fish are susceptible to exposure to toxic chemicals in the water. Pyriproxyfen is a pesticide widely used to control mosquitoes in drinking water supplies and pests in crops. The present study aimed to examine pyriproxyfen's effects on fish O. niloticus fingerlings exposed using an acute 96 h and subchronic tests for 28 days. The lethal concentration LC50−96 h for O. niloticus was 2.77 mg L−1, no observed effect concentration (NOEC), and the lowest observed effect concentration (LOEC) was 1.0 and 2.5 mg L−1, respectively. The hepatic catalase activity was significantly changed after exposure to pyriproxyfen above 0.4 mg L−1. Pyriproxyfen also induced histopathological lesions in the hepatic tissue at 28 days in a dose-dependent pattern at concentrations above 0.4 mg L−1. Pyriproxyfen above 1.2 mg L−1 reduced the locomotor behavior, distance traveled inside the tank, mean speed, and angular variation. This pesticide also decreased weight gain, food conversion, and specific growth rate at concentrations above 1.2 mg L−1. In conclusion, exposure to pyriproxyfen in water from 0.4 mg L−1 may impair O. niloticus development; consequently, pyriproxyfen may affect this fish's production and quality at higher concentrations than commonly used in water (0.01 mg L−1).

O uso do farelo de coco pode representar uma fonte alternativa na alimentação de peixe. Por esse motivo avaliaram-se os reflexos de sua utilização sobre o valor nutricional do filé de tilápia-do-nilo. O experimento foi realizado em um delineamento inteiramente ao acaso com 4 tratamentos (T1 - 0%, T2 - 10%, T3 - 20% e T4 - 30% de inclusão de farelo de coco) e cinco repetições. Foram determinados a composição centesimal, o teor de colesterol e os teores de ácidos graxos. Observou-se diferença (p < 0,05) entre T1 e T3, T2 e T3 para os teores de umidade; entre T2 e T3 para os lipídios; T1 apresentou diferença com relação aos demais tratamentos referentes aos carboidratos; e quanto aos teores de cinzas foi observada diferença de T1 e T2 entre T3 e T4. Os teores de colesterol apresentaram um aumento gradual significativo. Com relação aos ácidos graxos, observou-se diferença (p < 0,05) entre os tratamentos referentes aos C10:0; C12:0; C14:0; C18:1; C18:3 (gama); C20:3; e C22:6 numa proporção tal que não determinou diferença na qualidade nutricional do produto.

The use of coconut meal may represent an alternative source to fish feeding. The purpose of this work was to assess the impact of the use of coconut meal in Nile tilapia feeding and on the nutritional value of the fish fillets. The experiment was conducted in a completely randomized design with 4 treatments (T1 - 0%, T2 - 10%, T3 - 20%, and T4 - 30% for the inclusion of coconut meal) with five repetitions. The proximate composition, cholesterol, and fatty acids were determined. There was a difference (p < 0.05) between the treatments T1 and T3 and between T2 and T3 with regard to moisture levels; between T2 and T3 with regard to lipids; T1 and all the other treatments with regard to carbohydrates, and finally between T1 and T2 and between T3 and T4 with regard to ash. The cholesterol level showed a significant gradual increase following the increase in the inclusion of coconut meal. There was also a difference (p < 0.05) between the treatments concerning the following fatty acids: C10:0; C12:0; C14:0; C18:1; C18:3 (gama); C20:3 , and C22:6 , but the nutritional quality of the product was not affected.