Study looks at black soldier fly meal in laying hen diets

When Stephanie Collins thinks about insects as a poultry feed ingredient, she’s really thinking about the future. Collins and her research team at Dalhousie University have recently completed a feeding trial with black soldier fly larvae meal in laying hen diets.

“We aren’t the first to use insects but we are thinking about how to feed future generations and also looking to adopt more efficient environmental practices,” says Collins, an associate professor and animal nutritionist in the faculty of agriculture. 

Black soldier fly meal is showing signs of being a bit of a wonder feed, as an economical alternative protein in poultry diets to replace some of the corn or soybean content, and one that’s generated in a carbon negative environment. Already an approved feed ingredient in Canada, and in other countries around the world, widespread commercial production and adoption of the insect meal is a little way off. 

In the meantime, Collins and her team, including PhD student Jing Lu, are gathering valuable experience and information about the impact and opportunities of including black soldier fly meal in laying hen diets. 

They recently completed a four-month feeding trial with 180 laying hens to compare levels of black solider fly meal in layer diets – 0 per cent, 6.5 per cent or 13 per cent of the diet – in brown- and white-feathered birds. They measured hen performance, egg production, egg quality, diversity of microbes in the gut, production of short chain fatty acids in the gut, as well as the fatty acid composition of eggs.

“Our goal was to learn more about this up-and-coming feed ingredient to support gut health, food security and environmental sustainability,” says Collins. 

She credits her full team on this research – in addition to Lu – including Hannah Facey, Sarah MacPherson, Krista Budgell, Janice MacIsaac, Sasha Di Stefano-Pitre and Jamie Fraser.

More meal is better
Sometimes the most important finding in research is that the idea worked. That’s what Collins and Lu found with black soldier fly meal. 

“You don’t always get what you wish for in research,” says Lu. “But we did this time in terms of a more diverse gut microbiome with birds fed black soldier fly meal.”

In fact, they found that more is better. When birds were fed black solider fly meal in the diet, there was increased diversity in the gut microbiome. And the diversity increased with the percent of black soldier fly meal in the diet.

“At the 13 per cent inclusion level, both strains of birds had a more diverse microbiome community in the gut,” says Lu. “What was interesting was the white strain had a more naturally diverse gut microbiome at the beginning of the trial, but the brown strain hens basically caught up by the end of the trial.”

Lu says this could be beneficial if you feed black soldier fly meal to birds that have a less diverse gut at the start of the feeding period, as opposed to indicating the insect meal is more beneficial to brown-feathered birds.

Better bacteria in the gut
They also looked at short chain fatty acids in the gut, comparing them between the different levels of black soldier fly meal in the diet. Again, they found encouraging, positive results. 

Short chain fatty acids are formed when bacteria in the gut are metabolized. They saw a similar response to the gut microbiomes and more signs of improved gut health. “When we fed increased levels of black soldier fly meal, we saw a corresponding increase in acetic acid and decrease in butyric acid,” says Lu.

Better shelf life potential
When they analyzed the impact on egg quality and production, Collins and Lu found that including black soldier fly meal in the diet – at any level – had no negative effect. But again, they also found more encouraging news. 

“We saw an increase in lauric acid levels in eggs yolks as a result of feeding black soldier fly meal,” says Lu. “Birds fed 13 per cent black soldier fly meal were really good at assimilating the fatty acid from the meal and in turn making a big impact on the fatty acid profile of the egg yolk.”

That’s important because lauric acid is associated with antimicrobial effects – eggs with more lauric acid could have the potential for improved food safety with better shelf life and less spoilage. “That was a fun finding to realize the positive impact on the fatty acid profile in the egg yolk was the result of feeding black soldier fly meal,” says Collins.

What’s next
With all the positive findings from this trial with laying hens, Collins and Lu will be taking a closer look at what the bacteria are doing in the gut. “We’ll be looking at resilience and immune response in hens fed black soldier fly meal,” says Collins.

The bigger implications are that better gut health – that includes a more diverse microbiome – potentially contributes to a stronger immune response and better bird health. “We are really excited about this research and believe additional work is warranted to be sure that what we are finding is true to theory,” says Collins.

While there isn’t a consistent supply of black soldier fly meal available in Canada, Collins wants the industry to be ready. “We saw an improvement in many parameters we measured with black soldier fly meal,” says Collins. “Feeding insects is a tool that I’d like to be ready for producers if and when they want to use it.” 

The promise of black soldier fly meal

• Approved feed ingredient in Canada by CFIA
• Excellent source of protein and calcium
• Requires low levels of water and feed
• Efficient converters of low-value nutrients into high-value protein
• Rearing considered net negative for greenhouse gas emissions
• Can be farmed vertically
• Need for larger scale operations in Canada to provide more readily available, cost-effective product