Microencapsulates of Moringa oleifera seed extracts enhance immunological parameters of Almaco jack (Seriola rivoliana) upon Aeromonas hydrophila challenge.

Moringa oleifera seed (MoS) and spray-dried seed (Sd-Mo) were supplemented in experimental diets to Almaco Jack Seriola rivoliana, and sampled on weeks 2 and 4; also, resistance against Aeromonas hydrophila was evaluated. Chemical compounds were determined by GC/MS and polyphenols contents were determined in MoS. After 4 weeks of experimental trial, weight growth and bactericidal activity were evaluated in serum, while intestine content was obtained to determinate the short-chain fatty acids (SCFAs). Furthermore, remaining fish were challenged during week 4 against A. hydrophila, and immune response parameters were determined in serum; on the final day, fish were sampled to obtain leukocytes from head-kidney to evaluate innate immune parameters. The GC-MS analysis indicated that MoS contained 39 chemical compounds such as polyalcohol, in addition to the presence of phenols. The results revealed that Sd-Mo significantly increased (P < 0.05) weight gain after 2 and 4 weeks. Experimental diets supplemented with Sd-Mo showed significant increase on bactericidal activity against A. hydrophila A-315, as well as concentration of acetic (C2:0) acid obtained by SCFA in serum in this group of fish. After infection, total protein, lysozyme, nitric oxide and the antioxidant enzymes (SOD and CAT) were increased in serum from fish fed with Sd-Mo. Interestingly, ex vivo assay determined in head-kidney leukocytes revealed that fish fed with Sd-Mo increased their defense against A. hydrophila infection with enhanced phagocytosis, respiratory burst, myeloperoxidase, and nitric oxide production activities. In summary, this study suggested that fish fed with supplemented diets Sd-Mo (0.5 %) has a positive effect than not processed MoS, enhancing weight gain and in vivo and ex vivo immunological parameters after infection with A. hydrophila.