Small algae, big changes: how broiler chickens respond to high-chlorella diets

Farmers looking for plant-based feed alternatives often turn to microalgae like Chlorella vulgaris because it’s packed with nutrients and grows quickly. But when chickens ate diets where soy meal was swapped for 20 % Chlorella, something unexpected happened—growth slowed down and certain fats in the blood went up. Scientists tested three ways to fix the problem: plain Chlorella, enzyme-spiked Chlorella, and heat-treated Chlorella. Only the enzyme version (pancreatin at 0. 3 %) kept the birds’ weight gain close to normal, showing that digestibility is the real bottleneck. Without help, the algae’s tough cell walls and high fiber content block the absorption of energy and nutrients.The birds weren’t just lighter, though. Their livers started storing different kinds of fats and antioxidants. Chlorella diets cut the ratio of “healthy” to “less healthy” fatty acids and pumped up levels of specific fats, including palmitic acid and an omega-3 called EPA. The liver also held more cholesterol and colorful compounds like β-carotene and vitamin E precursors, especially when the algae was fed raw. These shifts suggest the microalgae can reshape metabolism, but they don’t necessarily improve growth unless enzymes are added. Looking at blood and liver samples under the microscope of statistics, researchers saw clear patterns. Plasma results split into four separate groups—one for each diet—while liver data only separated control birds from all Chlorella-fed groups. That means the liver reacts the same way to Chlorella whether it’s cooked, raw, or enzyme-treated, while the rest of the body adjusts differently depending on processing. In short, adding pancreatin is the simplest way to make high-algae diets work in the barn, turning a potential feed problem into an option that supports both bird performance and health.