Effect of Feeding 0.8% Dried Powdered Chlorella vulgaris Biomass on Growth Performance, Immune Response, and Intestinal Morphology during Grower Phase in Broiler Chickens

Simple Summary Chlorella vulgaris (CV) is a microalgae of great interest for broiler production, due to its nutritional and functional properties. Currently, expensive bioprocessing steps are used to acquire the functional components that could achieve the desired biofunctionality of CV, in particular to maintain productivity and support health in broilers. This makes CV an expensive feed ingredient that can only be used in low inclusion levels, otherwise the cost of the feed is too high. However, it is not clear whether low CV inclusion levels have positive effects on broiler production and immune response. This study investigated whether the addition of CV biomass, at a low inclusion level of 0.8%, to broiler diets maintained the functional properties of microalgae and improved broiler productive performance. We found that the addition of 0.8% CV biomass affects the immune response, and has positive effects on the overall productive performance of broilers. An experiment was performed to study the effects of a low inclusion level of Chlorella vulgaris (CV) biomass in broiler diets on performance, immune response related to inflammatory status, and the intestinal histomorphology. The study was performed with 120 Ross 308 male broiler chickens from 0-35 days of age. The broilers were housed in 12 floor pens (1.5 m(2)) bedded with wood shavings. The broilers received a three phase diet program, either with 0.8% CV biomass (CV) or without CV (CON). Each diet program was replicated in six pens. The final body weight increased (p = 0.053), and the feed conversion ratio (FCR), corrected for body weight, was reduced (p = 0.02) in birds fed CV compared to birds fed CON. In addition, decreased haptoglobins (p = 0.02) and interleukin-13 (p < 0.01) responses were observed during the grower phase of birds fed CV compared to the birds fed CON. A strong correlation (r = 0.82, p < 0.01) was observed between haptoglobin response and FCR. Histomorphology parameters of the jejunum were not different between the groups. It was concluded that the inclusion of 0.8% CV biomass in broiler diets is effective in influencing immune responses related to inflammatory status and promoting broiler growth.