Nutritional studies on rats and fish (carp Cyprinus carpio) fed diets containing unheated and heated Jatropha curcas meal of a non-toxic provenance

摘要

Unheated and heated (121deg C, 66% moisture; 15, 30 and 45 min) Jatropha seed meals of non-toxic provenance from Veracruz state in Mexico were evaluated using rats and fish. Seven Sprague-Dawley rats (70 g body weight) and 5 carp were used in each diettreatment. With rats, liveweight gain was highest for the casein diet followed by heated (30 min; only this treatment was studied using rats) and unheated Jatropha meal containing diets. The protein efficiency ratio (PER) for unheated and heated Jatropha meals was 37 and 86%, respectively, of the casein diet. Body weight gain, PER and feed conversion ratio of fish did not differ between unheated and heated (15, 30 and 45 min) Jatropha meal-containing diets fed for 35 days. Although these parameters were similar for the unheated and heated Jatropha meal-containing diets, liveweight gain, PER and protein productive value were highest and feed conversion ratio lowest with Jatropha meal heated for 15 min, suggesting that heat treatment for 15 min is optimum for the meal. Trypsin inhibitor and lectin activities decreased drastically (>83 and 99%, respectively) after 30 and 45 min of heat treatment and after 15 min, the residual lectin activity was negligible and the residual trypsin inhibitor activity was34%. The results, along with the nutritional parameters investigated, imply that Jatropha trypsin inhibitors and lectins do not have any adverse effects on carp at least up to 35 days of feeding. The nutritional value of Jatropha meal of the non-toxic provenance is high, and potential exists for its incorporation into the diets of monogastrics, fish and possibly humans.