Physiological and Productive Responses to Dietary Supplementation of Chlorella vulgaris in Growing Rabbits

Chlorella vulgaris (CV) acts as an immuno-modulator and growth enhancer, however, studies were concerned about its impact on growing rabbits. The present study was undertaken to evaluate CV addition on physiological responses and productive performance (feed intake, feed conversion ratio, body weight, mortality rate, and other parameters) of APRI rabbits. A total of 45 growing rabbits at their weaning age with an initial body weight of 574.8 ±11.79g were investigated. The rabbits were divided into three equal groups; the first group (G1) received a basal diet without any additions. While, the other two groups, G2 and G3 received basal diets that contained 0.5g and 1.0g CV/kg diets. The results revealed the positive impact of CV on immunity (IgA, IgM, and IgG) status, especially IgG, which was significantly higher in G3 than in G1. No negative effects of CV on kidney and liver functions, since the lowest levels of creatinine, blood urea, aspartate aminotransferase, and alanine aminotransferase were recorded in G3 compared with G1. Throughout the experimental period (8 weeks), G3 was the best group in feed intake with the lowest feed conversion ratio reflected on achieving the highest body weight compared to other experimental groups. No mortality cases were recorded in G3, while, G1 and G2 almost showed the same mortality rate (%). The histopathological examination of rabbits' intestines indicated that a less inflammation presence of rabbit intestinal cells has been noticed in G3 compared to G1 and G2. Therefore, it could be concluded that using CV at a level of 1.0 g/ kg in diet is the best level that can be used as a natural feed additive. This contributes to the health of growing rabbits by protecting their intestines against inflammation, lowering the mortality rate, and ultimately improving their overall productivity.