Dietary supplementation with chitin and chitosan on haematology and innate immune response in Epinephelus bruneus against Philasterides dicentrarchi

The present study investigated the effect of 1.0% chitin and chitosan supplementation diets on haematology and immune response in Kelp grouper, Epinephelus bruneus against protozoan parasite, Philasterides dicentrarchi. The red blood cells (RBC), white blood cells (WBC), haemoglobin levels, lymphocytes, monocytes, and neutrophils significantly increased in kelp grouper fed with chitin or chitosan enriched diets against P. dicentrarchi. The mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and thrombocytes did not significantly change against pathogen. The phagocytic activity, respiratory burst activity, complement activity, antiprotease activity, and α2-macroglobulin were significantly enhanced in fish fed with 1% chitin and chitosan diet on weeks 2 and 4. The lysozyme activity, total protein, and myeloperoxidase activity significantly increased in fish fed with chitin or chitosan supplementation diet from weeks 1 to 4 against pathogen. The cumulative mortality was found low in fish fed with chitin and chitosan enriched diets than those of control against pathogen. The present study suggests that supplementation of 1.0% chitin or chitosan in diets positively enhances immune response and affords disease resistance in kelp grouper, E. bruneus against P. dicentrarchi infection.