Probiotic supplementation on hematology and recruitment of policariontes macrophages in the Nile tilapia challenge with Aeromonas hydrophila and Streptococcus iniae

Abstract

Supplementation with probiotics has shown promising results in performance and in defense mechanisms in fish. These features contribute to the aquaculture activity, especially in the prophylaxis and prevention of diseases. Substances added to the diet of fish receiving the response of defense mechanism is called immunostimulants, which are characterized by biological or synthetic compounds that increase the efficiency of the mechanisms of specific immunity and non-specific. Are represented by combinations vitamins, trace minerals, products derived from plants or animals known as probiotics, pre-biotic and others. The objective of this test is to analyze the hematological parameters and recruitment of macrophages policariontes in Nile tilapia, Oreochromis niloticus fed probiotic composed of Bacillus subtillis, Saccharomyces cerevisiae and Aspegillus oryzae and subject to challenge with the bacteria Aeromonas hydrophila and Streptococcus iniae. For both, the fish will be fed for a period of time with the probiotic and them, glass blades will be implanted in the subcutaneous tissue of the fish. After pre-determined time (2, 7 and 14 days after implantation), the blades will be removed and analyzed for the migration of macrophages and assessed the haematological parameters. After this experiment, the fish will be challenged to experimental infections with the bacterias Streptococcus iniae and Aeromonas hydrophila and by intra-peritoneal inoculation and evaluated haematological changes, respiratory burst and survival of fish. (AU)