Vitamin C dietary supplementation influence tadpoles of bullfrog Lithobates catesbeianus reared in low water temperature

Abstract

Vitamin C supplementation is important for the growth and development of bullfrog tadpoles under optimum water temperature conditions. Therefore, an experiment was carried out to evaluate the effects of vitamin C supplementation on the diet of bullfrog tadpoles at a low temperature. A total of 480 tadpoles with a mean weight of 0.078 g were distributed in 12 aquariums each containing 40 L of water in a closed water recirculation system. The experimental design was entirely randomized with four treatments (0, 150, 300, and 600 mg kg-1 of L-ascorbic acid monophosphate) and three replicates. The productive performance was measured by the weight gain, feed conversion, diet consumption, protein efficiency, carcass yield, hepatosomatic index, viscerosomatic index, visceral fat index, dry matter, and ethereal carcass extract. The water temperature during the experimental period was 21.74 ± 0.43 °C. Vitamin C supplementation did not influence carcass yield and viscerosomatic index. However, there was a quadratic effect of vitamin C supplementation on the weight gain, apparent feed conversion, protein efficiency, visceral fat index, hepatosomatic index, and ethereal carcass extract. Based on these results, bullfrog tadpoles should be supplemented with 600 mg vitamin C kg-1 of the diet when subjected to water temperatures of around 22 °C.