Its use would reduce dependence on crops with high environmental impact, maintaining productivity and improving the nutritional quality of milk and meat.
ANA S. GONZÁLEZ
Scientific interest in insects as raw material for human and animal food is skyrocketing. Every year researchers publish more than three hundred articles on this topic; just two decades ago they barely exceeded ten. Among its great virtues is its high protein content and the environmental advantages of its production.
Although much of the world’s research has focused on insect meals as an alternative source of protein, the Mountain Livestock Institute (IGM, CSIC-ULE), located in neighboring León, focuses on a less studied component, but of enormous interest, oils, which are also, unlike meals, allowed in the diet of ruminants in Europe.
This opens the door to its immediate use. A systematic review of recent scientific literature, led by IGM researchers, shows that insects used as ingredients in animal feed contain mostly fatty acids common in livestock diets, such as palmitic, stearic, oleic or linoleic.
Their relative percentages confirm that these are fats technically comparable to those of vegetable origin. “The black soldier fly stands out for its richness in medium-chain saturated fatty acids, similar to coconut or palm kernel oil, while the mealworm has a profile rich in oleic and linoleic acid, similar to that of rapeseed, soybean or sunflower oil,” says Pablo Gutiérrez Toral, CSIC researcher at the IGM.
The composition can also be adjusted by modifying the breeding substrate, which makes these oils versatile and modular ingredients.
Faced with the challenge of reducing their dependence on imported raw materials for food, especially soy and palm oil, whose production is associated with deforestation, the loss of biodiversity and high carbon emissions, insects are presented as a promising, efficient and sustainable alternative.
«The interest is twofold, on the one hand, reducing the environmental footprint of livestock production; on the other hand, modulate the nutritional quality of derived products, meat and milk, through the lipid profile of the diet,” the researcher specifies.
One of the studies led by the IGM in recent years evaluated the replacement of palm oil with black soldier fly oil in Assaf sheep. The trial demonstrated that replacing 2% of the dry matter of the feed with this oil kept the level of milk production unchanged, with no differences in either feed efficiency or ruminal fermentation.
The composition of the milk also did not change, which shows that this ingredient can replace lipids of plant origin, of less sustainability, without compromising productivity. Later work analyzed how it influences the composition of milk fat and concluded that it increases some fatty acids considered beneficial and reduces others without affecting production or overall quality.
The Leonese institution collaborated with the University of Turin (Italy) by replacing hydrogenated palm oil in the diet of dairy cows with black soldier fly oil, without negative changes in digestion and in the composition of fatty acids in the rumen. Milk production, however, increased by almost a liter a day.
Another study analyzed mealworm oil. In in vitro studies with typical rations of fattening lambs and dairy sheep, it behaved similarly to soy or palm distillates, without affecting digestion or ruminal fermentation.
All of this leads Gutiérrez Toral to affirm that insects constitute a “sustainable and viable alternative” for feeding ruminants and that their oils allow us to reduce dependence on crops with high environmental impact, maintaining productivity and improving the nutritional quality of milk and meat.
