Efficacy of feeding glucosinolate-extracted crambe meal to broiler chicks

Glucosinolates and their breakdown products (nitriles) have long been implicated as toxic factors when feeding rapeseed (Brassica napus) meals and crambe (Crambe abyssinica) meals to poultry. Accordingly, various methods have been developed to remove these compounds from the meals to enhance their value as feed supplements. Glucosinolates and nitriles were extracted from commercially processed, defatted crambe meal by washing with water or various solvent-water mixtures: 50% isopropanol, 50% acetone, or 50% ethanol. In addition, crambe seed was extruded and extracted in the laboratory with isopropanol or hexane. Water washing of commercially defatted meal proved to be the most effective method of extraction, removing 95% of the glucosinolates and nitriles. Meals were fed to 7-d-old broiler chicks at 10% of the diet for 14 d. Weight gain decreased (P < .05) in most groups; however a greater decrease (P < .01) was observed in birds fed meals with high glucosinolate content. Feed intake also decreased (P < .05) in most groups; consequently, feed efficiencies were similar for all groups. No changes in serum chemistries, triiodothyronine, thyroxine, or tissue lesions were associated with glucosinolate or nitrile intake. A relationship (P < .05, r = .74) was found between weight gain and glucosinolate intake. No correlation was found between feed intake and meal glucosinolate or nitrile concentrations.