Alternative sources of proteins in farm animal feeding

The global demand for protein is on the rise owing to the exponential increase in the world population and to meet the global protein requirements, it is imperative to seek alternative sources of proteins in farm animal feeding. Recognizing the importance of proteins and the fact that a major portion of human protein requirements is derived from livestock in the form of meat, milk, and eggs, the available protein-feeding stuff in the form of soybean meal cannot be regarded as sufficient for feeding to livestock. Oil seeds such as rapeseed meal and canola meal have a crude protein content of 30%-40% and are widely used and hence a potential alternative protein source to soybean meal. Going forward, Grain legumes such as peas, faba beans, and lupins, another alternative source of proteins have the potential to replace traditional protein feeds completely or partially such as bone and fish meals. Duckweed with a protein content of 20%-45% is another plant-based potential protein source that can be employed in livestock feeding particularly pigs owing to its huge potential as a growth promoter as evidenced by studies in pigs and piglets. Because of their nutritional qualities and possible environmental advantages, insects represent another class of alternative protein sources that have enormous potential to function as sustainable protein sources. Several insect species have been assessed for use as animal feeds; the most promising ones include the yellow mealworm (Tenebrio molitor, TM), the common house fly (MD), and the black soldier fly (Hermetia illucens, HI). Byproducts from aquaculture and fisheries are abundant in macro- and micronutrients, and their utilisation can provide fishmeal and fish oil, which can then be further adapted for use as a source of protein in animal nutrition. Employing microalgae as an alternative source of protein in animal feeding is somehow a new concept. Many nutritional and toxicological studies have demonstrated the potential of algae biomass as a valued feed supplement or substitute for conventional protein sources such as soybean meal. While these alternative protein sources in livestock feeding may serve as useful tools, parameters such as feed safety and acceptability should be monitored based on feed safety regulations.