Adição de vitamina C na ração para alevinos de Tilápia do Nilo

Abstract

The influence of productive performance of male fry Nile tilapia (Oreochromis niloticus) from the GIFT strain was verified, with different levels of vitamin C added to the diet during 56 days of cultivation. Initially, the masculinized fry had an average weight of 0.5 g and were submitted to diets containing: 0 mg, 10 mg and 20 mg of vitamin C per kg of feed. The experimental design was completely randomized, with three treatments and four replications. 360 Nile tilapia fingerlings were grown in a water recirculation system, randomly dividing them 30 fingerlings in each 40-liter usable box. The variables of the physical and chemical parameters of the water of the recirculation system were monitored in each experimental unit, keeping within the ideal for the species, temperature 26 ° C, pH 6.1 and dissolved oxygen 3.07 mg / L. There was no significant difference in the final average weight and weight gain with 0, 10 and 20 mg of vitamin C per kg (P> 0.05). There was no significant difference for the rates of average daily weight gain and final biomass for treatment with 0 mg / kg compared to treatments with 10 and 20 mg / kg (P> 0.05). There was a significant difference for the specific growth index in relation to the levels of vitamin C addition, 0, 10 and 20 mg / kg (P <0.05). It was observed that the fry supplemented with 10 and 20 mg / kg had a higher feed intake and feed conversion than the treatment with 0 mg / kg. There not was a significant difference in the survival rate with supplementation of 10 mg / kg, with 85.83% (P <0.05). It is concluded that the parameters of productive performance observed in the cultivation of masculine fingerlings of Nile tilapia are influenced by the levels of ascorbic acid in the amounts of 10 mg / kg and 20 mg / kg added to the commercial diet, except for the specific growth parameter, that there was a significant difference (P> 0.05) for the addition levels of 10 mg / kg.