Relevance of insect proteins in ruminant nutrition: A critical review

Environmental and demographic pressures have driven researchers to explore alternative protein sources for soybean meals and fish meals in ruminant nutrition. Among these alternatives, insects have emerged as a promising option due to their high protein content and well-balanced amino acid profiles. However, most studies identify regulatory restrictions on processed animal proteins as the primary limitation to their inclusion in ruminant diets. This critical review aims to go beyond regulatory concerns by highlighting the physiological and functional limitations of using insect proteins in ruminant nutrition. Special emphasis is placed on the unique aspects of ruminant nitrogen metabolism, the current limitation due to the cost of these proteins, the issue of feed–food competition, and the current methods used to assess insect protein value. In doing so, this review seeks to provide a more nuanced understanding of the challenges and potential of insect-based proteins for sustainable ruminant feeding systems.