Recent Trends in the Nutritional Value of Mealworm(Tenebrio molitor) and Its Feeding Effects in Monogastric Animals

With the global increase in population and the growing demand for livestock products, the need to secure sustainable feed ingredients has become increasingly important. Conventional major protein sources, such as soybean meal and fish meal, are limited by high price volatility and environmental burdens, prompting attention toward Tenebrio molitor as a promising alternative insect protein. Mealworms are characterized by high crude protein and crude fat contents and excellent digestibility, indicating substantial potential as an alternative protein source for monogastric animal diets. However, their proximate composition as well as amino acid and fatty acid profiles may vary depending on larval developmental stage, processing and pretreatment methods, and the nutrient composition of the rearing substrate. In addition, concerns regarding reduced oxidative stability and the potential generation of toxic compounds associated with their high fat content should also be considered. According to this review, dietary inclusion of mealworm powder in swine diets for weaned and growing pigs did not adversely affect overall growth performance, nutrient digestibility, or immune responses; however, partial reductions in productivity were observed when conventional protein sources were replaced at excessively high levels. In poultry diets, mealworm supplementation showed positive effects on early growth performance in broilers, while in laying hens, productivity and egg quality were generally maintained at low inclusion levels, although negative outcomes were observed at high dietary inclusion rates. In conclusion, for mealworms to be used as a stable alternative feed ingredient for monogastric animals, standardization of insect rearing and feed formulation is required to minimize variation in larval body composition, and precise determination of optimal inclusion levels considering the physiological characteristics of each livestock species is essential.