Growth of Nile tilapia post-larvae from broodstock fed diet with different levels of digestible protein and digestible energy

This study was carried out to evaluate the influence of different levels of digestible energy and digestible protein in diets of Nile tilapia (Oreochromis niloticus) broodstock on offspring growth during sex reversal stage. A total of 2,700 post-larvae (8.2±0.001 mg) derived from breeders fed nine diets with distinct levels of digestible protein (28, 34 and 40% DP) and digestible energy (2,800; 3,400; and 4,000 kcal DE.kg-1) were stored in twenty-seven 70 L tanks. After 30 days of growth, their average final weight (AFW, g), average weight gain (AWG, g), final standard length (SL, cm), condition factor (CF), specific growth rate (SGR, %/day), stock uniformity (UNI, %), survival (SUR, %) and sex reversal rate (SRR, %) were measured. Although female nutrition is thought to influence the performance or quality of progeny during early life stages, no influence of diets supplied to broodstock was detected on any parameter. Nonetheless, the offspring presented commercially satisfactory growth rates. Thus, diets containing 28% of digestible protein and 2,800 kcal of digestible energy.kg of diet-1 can be used to feed Nile tilapia broodstock without jeopardizing offspring performance during the sex reversal phase

Hypervitaminosis induced by vitamin A supplementation in ration for post larvae of Nile tilapia

O presente trabalho foi realizado para avaliar os efeitos da hipervitaminose por meio de suplementação de diferentes níveis de vitamina A em rações balanceadas, sobre o desempenho da tilápia do Nilo (Oreochromis niloticus) durante a fase de reversão sexual. O período experimental foi de 30 dias, com um delineamento inteiramente casualizado com seis tratamentos e cinco repetições. Foi considerado como unidade experimental um aquário de 50L contendo 70 pós-larvas. O primeiro tratamento constituiu de uma ração onde foi adicionado apenas o premix comercial como fonte de vitamina A (30 KUI). Os outros foram suplementados com 1.030, 2.030, 3.030, 4.030 e 5.030 KUI de vitamina A. Ao final do experimento os peixes foram avaliados quanto ao peso médio final (PMF), aos comprimentos total final (CT) e padrão final (CP), ao ganho de peso médio (GPM), ao ganho de biomassa (GB), a conversão alimentar aparente (CAA), ao fator de condição final (FC) e à sobrevivência (%). Os resultados de PMF, CP, GPM e GB mostraram um efeito linear negativo (P<0,05) em relação ao aumento dos níveis de vitamina A na ração. Conclui-se que a inclusão de vitamina A em níveis acima de 30 KUI prejudicam o crescimento das pós larvas de tilápia do Nilo. The present study was carried out to evaluate the effect of the hypervitaminosis by supplementation of vitamin A in balanced ration, on the performance of Nile tilapia (Oreochromis niloticus) during sex reversal phase. The experiment was carried out during 30 days in a randomized experimental design with six treatments and five repetitions. Was considered an experimental unit an aquarium of 50L contends 70 post larvae. The first treatment was consisted by a ration where was added only commercial premix how a vitamin A (30 KUI) source. The others had been supplemented with 1.030, 2.030, 3.030, 4.030 e 5.030 KUI of vitamin A. At the end, the final average weight (FAW), the standard (SL) and total length (TL), the weight gain (WG), the biomass gain (BG), the apparent feed conversion (FA), the condition factor (CF) and the survival (SU) were assessed. The results of FAW, SL, WG and BG showed a negative linear effect (P<0,05) by the increase of the vitamin A in the ration. The hipervitaminosis of vitamin A above of 30 KUI damaged the post larvae Nile tilapia growth