Nutritional evaluation of wheat and barley cultivars by growth rate and body composition of larvae of Tenebrio molitor.

Larvae of the yellow mealworm, Tenebrio molitor L., Gembloux strain, race F, were reared on diets of 17 cultivars of wheat and 29 cultivars of barley, prepared for determination of digestible energy with mice, for 4 weeks at 27 +/- 0.25 degrees C and 65 +/- 5% relative humidity. Values for percentage crude protein of tissues of larvae fed wheat cultivars were significantly and positively correlated with values for digestible energy as determined with mice. These values were not correlated for larvae fed barley cultivars; however, values for per cent dry matter content of larvae were significantly and positively correlated with values for digestible energy determined with mice. This apparent discrepancy is explained on the basis of the chemical constitution of barley and the availability of amino acids of barley to the larvae. Use of larvae of Tenebrio molitor to indicate the digestible energy of cereal grains is feasible, provided that the proper parameter is chosen. Nevertheless, use of this biological method seems more suitable for evaluation of protein quality and of amino acid availability than for a measure of digestible energy of feeds.