Rearing of Hermetia Illucens on Different Organic By-Products: Influence on Growth, Waste Reduction, and Environmental Impact

In the last few years great efforts have been made to find alternative protein sources to soybean meal and valorize organic by-product, which are produced in large amounts by food industries and are often inedible by humans. In this context, insects could be an alternative protein source. The aims of this study were to evaluate the growth performance, nutrient composition, and environmental impact of Hermetia illucens reared on a control hen diet and by-products diets (okara, maize distillers, and brewer’s grains). The rearing substrate affected larvae growth performance, nutritive value, and environmental impacts. Larvae fed on a hen diet and the maize distiller exhibited the higher final weight and required fewer days to reach the prepupal stage. The lipid content of the larvae was positively correlated to that of the insect diets. The environmental impact of larvae production on the hen diet, characterized by a high inclusion of soybean meal, was the most impactful for most of the environmental categories. Feed production activities were the main contributor to environmental impact. The use of by-products for larvae growth allowed us to reduce the environmental impact to produce 1 kg of protein in comparison with the use of soybean meal as a protein source