Effect of commercial processing of canola and rapeseed on growth of larvae of the yellow mealworm, Tenebrio molitor L.

Larvae of Tenebrio molitor L., Gembloux strain, race F, were used to determine the nutritional quality of commercial canola and rapeseed products. Application of heat in commercial processing increased considerably the nutritive values of Midas, Tower and Torch cultivars, and to a lesser extent that of Candle. This improvement was most noticeable for thigh-glucosinolate cultivars, presumably through the destruction of a mechanism for production of isothiocyanates that may be phagodeterrent or toxic to the larvae. For low-glucosinolate varieties, the improvement may be related to inhibition of nitrile production in heated material. The processing also reduced the concentration of available lysine in the products of all four cultivars; however, growth was unimpaired by this reduction. The latter results suggest that the feed products resulting from processing may exceed the optimal dietary requirement of lysine by larvae of Tenebrio molitor.