Orally administered [beta]-glucan improves the hemolytic activity of the complement system in horses

Background and Aim: Immune-modulating molecules mainly act on innate immune cells, which are central to early defense against invading pathogens and contribute to developing adaptive immunity. Yeast-extracted [beta]-glucan, a model immune-modulating molecule, is widely used in several animal species; however, its effect on horse immune parameters has not been thoroughly investigated yet. This study aimed to evaluate the effects of orally administered [beta]-glucan on selected innate immune parameters in horses. Materials and Methods: Eighteen thoroughbred horses were assigned equally into three groups as follows: One control group (no [beta]-glucan) and two [beta]-glucan experimental groups (one received 125 mg and the other 2 g of [beta]-glucan per day for 28 days). Blood samples were collected before and at the end of the experiment for hematological analysis, whole blood phagocytosis, respiratory burst assays, and to assess the serum lysozyme and complement hemolytic activities. Results: At the end of the experiment, significant decreases (p