Effects of dietary supplementation with a chlorella by‐product on the growth performance, immune response, intestinal microflora and intestinal mucosal morphology in broiler chickens
Algae species are available that produce novel compounds. Among these, Chlorella (Chlorella vulgaris) is an important unicellular green micro‐alga that is used for human food, animal feed, bio‐fertilizers, biofuels and the development of pharmaceuticals (Borowitzka, 1988; Beecker, 2004). It contains nutrient components (protein, fat, fibre, carbohydrate, vitamins and minerals) and active compounds (phycobilins, phenol, terpenoid, steroid and polysaccharide) which play a role as antibiotic and antioxidant (Chen et al., 2011). It has been reported that supplementation of Chlorella in human and animal diets performed numerous biochemical and physiological functions (Lee et al., 2010) and immunomodulation (Guzman et al., 2003). Research has been conducted to the possibility of using Chlorella in poultry diet (Halle et al., 2009; Kang et al., 2013). In poultry rations, algae up to a level 5–10% can be used safely as partial replacement for conventional proteins (Spolaore et al., 2006). Ginberg et al. (2000) showed a significant reduce in the serum content of cholesterol and triglycerides of rodents fed with red algal biomass. Also, there is evidence showing efficiency of chlorella in reducing total lipid and the cholesterol in the serum (Okudo et al., 1975; Skjanes et al., 2013). More recently, work has been conducted to study the potential health benefits of chlorella to improve the growth performance of birds by increasing the intestinal microbial population (Kang et al., 2013; Kim and Kang, 2015). Composition and nutrient of micro‐algae influenced by some factors such as nutrition difference, environment and growth phase (Mata et al., 2010). We hypothesized that the active substances in Chlorella by‐products (CBPs) affect the immune response, morphology, intestinal microflora activity of chickens. Therefore, this study aimed at determining the effect of inclusion level of CBP on growth performance, immune response, morphology and intestinal microflora of broilers.