Evaluating the use of expanded polystyrene-reared yellow mealworm as a replacement for soybean meal in broiler diets

This experiment evaluated the effects of partially replacing soybean meal (SBM) with yellow mealworm ( Tenebrio molitor L.) meal (MWM) reared on either wheat bran (CMW) or expanded polystyrene (EMW) on broiler chicken growth performance, carcass traits, nutrient digestibility, and the intestinal morphology for 35 days. A total of 336 one-day-old male Ross 308 broiler chicks were randomly assigned to seven dietary treatments, each consisting of six replicates (eight chickens per cage). Dietary treatments included: (i) corn-SBM diet (Control); (ii) a diet including CMW 5% (CMW5); (iii) a diet including CMW 10% (CMW10); (iv) a diet including CMW 15% (CMW15); (v) a diet including EMW 5% (EMW5); (vi) a diet including EMW 10% (EMW10); and (vii) a diet including EMW 15% (EMW15). Results indicated that MWM, irrespective of substrate type, improved body weight ( ), average daily gain, and daily feed intake in broiler chickens compared to the control group. On day 21, broilers in the EMW groups had a higher dressing percentage than CMW groups ( ). Compared to the control, crude fat digestibility increased in the CMW5, CMW15, EMW10 and EMW15 groups ( ). In conclusion, substituting SBM with up to 15% MWM, irrespective of rearing substrate (wheat bran or expanded polystyrene), improved broiler growth performance, carcass characteristics, and fat digestibility without adverse effects on intestinal morphology or nutrient digestibility. Moreover, mealworms raised on expanded polystyrene showed comparable performance to those raised on wheat bran, suggesting their potential as a sustainable protein source in broiler diets.