Fontes de óleos vegetais na dieta de rã-touro (Lithobates catesbeianus)

Abstract

The Bullfrog (Lithobates catesbeianus) is a species explored worldwide due to its easy adaptation to climatic conditions, its easy cultivation and excellent meat quality. The objective of the present work was to evaluate the performance of the Bullfrog (L. catesbeianus) fed with diets containing different vegetable lipid sources. For this purpose, 96 juvenile frogs were housed in 12 plastic boxes with a volume equal to 70 liters containing 8 animals per experimental unit, in a completely randomized design containing 4 treatments (sunflower, olive, corn and soybean oil) and 3 replications. The experiment lasted 61 days, during this period, a commercial fish feed with 40% protein and 2% inclusion of each oil source was offered. The animals received the diet at 3% of live weight per day, divided into 4 meals. The correction of the ration rate took place every 20 days. At the end of the experimental period, all animals were weighed, measured and counted, and three specimens from each box were slaughtered. Performance parameters were evaluated, such as final weight (g); weight gain (g), final length (cm), liver somatic index, visceral fat, intestinal quotient, feed conversion ratio, protein efficiency ratio (%), specific growth rate (%), feed efficiency and survival (%). Among the metabolic and biochemical analyses, blood was collected to measure glucose, triglycerides, total cholesterol and creatinine. In liver tissue, triglycerides were measured. Visceral fat, liver and intestine were collected to determine the amount of visceral fat (IGV), hepatosomatic index (IHS) and intestinal quotient (IQ). There were no statistical differences between the variables corresponding to zootechnical performance as a function of the supplementation of different oil sources (p>0.05). Among the blood metabolites, only creatinine was superior (p<0.05) in frogs fed a diet supplemented with soy oil, the other parameters, glucose, triglycerides and cholesterol were not changed, whereas the hepatic triglyceride of frogs fed with oil of corn was superior to the treatment with sunflower oil, but similar to the other treatments. Regarding the organo-body indices, IHS and IGV were similar between treatments, however, the IQ was higher (p<0.05) in animals that received the diet with the addition of soy oil (5.33±0.73) compared to those who received the diet including olive oil. It is concluded that the use of vegetable oil sources does not present changes to the zootechnical performance parameters of frogs, thus the use of soy oil is recommended, as it is an easy-to-purchase product and has a lower purchase value compared to other oils.