As the global population grows, so does the demand for animal protein, placing increasing pressure on livestock systems to produce more wit fewer natural resources. This challenge has led researchers and agricultural scientists to seek alternative, more sustainable protein sources. One emerging solution is insect protein—particularly mealworm larvae (MWL) and black soldier fly larvae (BSFL)—as a viable alternative to conventional feeds like soybean meal. In a recent study published in Translational Animal Science, researchers explored how these insect proteins could benefit cattle fed low-quality forage, a diet commonly found in resource-limited environments.
Insects are gaining attention for their potential in livestock nutrition due to their high protein content, scalability, and efficient use of natural resources. Mealworm larvae and black soldier fly larvae have been explored as protein sources for monogastric animals like poultry and swine, but their use in ruminant diets, particularly for cattle, is relatively novel. These insects can transform organic waste into nutrient-rich biomass, making them an attractive option for sustainable feed.
This study aimed to evaluate how MWL and BSFL would perform as protein supplements for cattle, comparing their effects on forage intake, digestion, and fermentation to a traditional protein source, soybean meal, and a control diet without any supplement.
Control (CON): No protein supplement.
Soybean meal (CONV): Traditional feed protein.
Black soldier fly larvae (BSFL): Defatted insect protein.
Mealworm larvae (MWL): Whole-dried insect protein.
MIX: A 50/50 blend of MWL and BSFL.
The cattle consumed a low-quality forage with only 4.2% crude protein, simulating the type of forage often available in drought-affected or resource-poor regions. Over several periods, the researchers measured forage intake, total digestible organic matter, digestibility, and ruminal fermentation to assess the effects of the different protein supplements.
1. Increased Forage Intake
Protein supplementation significantly increased the cattle's forage intake compared to the control group that received no supplements. Interestingly, the mealworm larvae (MWL) stimulated higher forage intake than the black soldier fly larvae (BSFL), though both were effective in enhancing consumption.
Control: 3.28 kg/day of forage organic matter intake.
Soybean meal: 4.71 kg/day.
Mealworm larvae: 4.43 kg/day.
Black soldier fly larvae: 4.30 kg/day.
This shows that MWL, in particular, holds great potential as a forage intake stimulant, similar to conventional protein sources.
2. Enhanced Total Digestible Organic Matter
Protein supplements, including insect-based ones, led to a noticeable increase in total digestible organic matter (TDOMI). The cattle receiving MWL, BSFL, or soybean meal digested more organic matter than those in the control group.
The control group had a digestible organic matter intake of 1.94 kg/day, while cattle receiving supplements averaged 3.24 kg/day across treatments.
3. Stable Digestibility
Despite the increased intake, there were no significant differences in digestibility among the different protein supplements. This indicates that while MWL and BSFL boost intake, they do not affect the cattle’s ability to digest their diet.
Organic matter digestibility averaged 66.5%, and neutral detergent fiber digestibility was 62.7% across all groups.
4. No Disruption to Rumen Fermentation
The study also measured ruminal volatile fatty acids (VFA) and ammonia-N concentrations, both key indicators of rumen health and fermentation. The results showed that neither MWL nor BSFL disrupted normal ruminal fermentation, suggesting they are safe and effective protein supplements for cattle.
The Sustainability Angle
The use of insects as protein sources for livestock not only boosts forage utilization but also presents a more sustainable approach to cattle farming. Insects like MWL and BSFL can be raised on organic waste, reducing reliance on resource-intensive crops such as soybeans. Moreover, insect farming has a significantly lower environmental footprint compared to traditional livestock farming, making it a win-win for both farmers and the planet.
With soybean meal being a staple in livestock feed, insect proteins offer a promising alternative that can help reduce the environmental impact of animal farming while meeting the nutritional needs of livestock. By providing a sustainable, scalable protein source, insects could play a vital role in the future of food security and animal nutrition.
Incorporating MWL and BSFL into cattle diets not only helps meet global food demands but also contributes to a more sustainable agricultural future. Further research could explore the scalability of insect farming and its integration into commercial cattle operations, paving the way for a greener, more resource-efficient livestock industry.