Farelo de pinhão-manso destoxificado na alimentação da tilápia-do-nilo

Abstract

Jatropha curcas cake/meal is an alternative protein feedstuff with potential to replace soybean meal in fish diets. Due to the presence of toxic compounds (phorbol ester) and some anti-nutrients, a detoxification process is recommended. However, there is not sufficient information regarding its nutritional value and the action of anti-nutritional factors in fish feeding. Levels of jatropha meal (DJM) detoxified by solvent, followed by extrusion in diets of Nile tilapia (Oreochromis niloticus) was evaluated for 65 days. A total of 200 fish with 3.59 ± 0.06 g initial weight were distributed in 20 cages (70 L) in a completely randomized design. The fish were fed diets (isonitrogenous CP = 26.81%, isoenergetic = 12.71 KJ of DE g-1 and isofibrous = 6.41% of CF) containing increasing levels of DJM (0.0, 3.0, 6.0, 9.0 and 12.0%) corresponded to five treatments and four repetitions. The average final weight, weight gain, specific growth rate, feed conversion ratio, and total feed intake presented a decreasing linear effect (p < 0.05). Data showed that hemoglobin, mean corpuscular volume, hepatosomatic indexes of visceral fat, intestinal quotient, total plasma protein, triglycerides, and lipid levels, iron and zinc in the fillet reduced significantly (p < 0.05). The opposite was observed for aspartate and alanine aminotransferasis, as well as for concentrations of phosphorus and magnesium in the fillet. Hematocrit, erythrocyte, mean corpuscular hemoglobin concentration, digestive and esplenossomatic indexes, cholesterol and glucose, and total protein, calcium and copper in the fillet were not affected by the different treatments. Fish showed mortality from the second week counting from the beginning of the experiment, with a survival of 100, 65, 90, 70 and 50% for DJM 0, 3, 6, 9 and 12, respectively, without difference (p > 0.05). The anti-nutritional factors and toxic residues present in the jatropha provided negative performance and fish health.