This study showed the uses of garlic (Allium sativum) supplemented feed on Clarias batrachus for the judgment of garlic potential against Acanthocephala. Garlic allicin content (an active component of garlic) worked for C. batrachus to inhibit infection by Acanthocephala. Four garlic supplemented diets (50, 100 150 and 200 ml/kg) of different concentrations and a non-supplemented control diet were fed to C. batrachus for three months. Long-term (90 days) supplementation with garlic significantly reduced infection success by up to 80% as compared to controls and did not negatively affect palatability of the feed, Specific Growth Rate (SGR) (3.60±0.13) and Food Conversion Ratio (FCR) (2.33±0.38). Infection success was not influenced by short-term (30 days) supplementation suggesting that a delayed host response must occur to improve resistance to infection [prevalence (71%, 35%) and intensity (0.8, 0.5)] and 60 days conditioning period showed reduction of parasite respectively [prevalence (75%, 25%) and intensity (1, 0.6). Incorporation of garlic into a pressure-extruded pellet was found to be an effective method of delivery as only minimal leaching of allicin from the diet occurred (˂ 3% of allicin detected) during the interval of water contact between delivery and consumption. This study demonstrates that garlic extract (200 mL/kg) administered as a dietary supplement is one of the most practical methods to prevent Acanthocephala infection in Aquaculture.

Streptococcus iniae is an important pathogen that can cause a broad range of disease in aquatic animals. To avoid the use of antibiotics and drugs, it is critical to identify protective antigens for developing highly effective vaccines against this pathogen. Vaccination is the most effective means of preventing infectious diseases; however, few vaccines are effective against Streptococcus iniae (S. iniae) in monosex Nile Tilapia. This work presents an efficacious and safe vaccine against S. iniae infections in monosex Nile tilapia (Oreochromis niloticus). The vaccine candidate S. iniae F-1 strain administered by intraperitoneal (i.p.) injection, and consisted of inactivated antigens; both the vaccinated and nonvaccinated fishes were challenged intraperitoneally with S. iniae (1 × 10 7 CFU ml −1 ) isolates and PBS (negative control). Peripheral blood samples were collected for SDS-PAGE, phagocytosis and agglutination assays. Present results indicated that immunoglobulin M (IgM) was maximally expressed in the low-amperage electric current inactivated (ECKC) vaccinated group at 3 months post-secondary vaccination (PSV). Phagocytic activity and index increased significantly in (ECKC) vaccinated group. Furthermore, fish in (ECKC) vaccinated group exhibited significantly elevated agglutination titers compared to fish in the control group, in which almost no agglutination reaction was detected. In the efficacy test, the vaccinated fishes had a significant increase in RPS (69 and 89, respectively); the percentage mortality declined from 83 ± 0.6 and 74 ± 0.7 in challenged and control fishes to 25% ± 0.8% and 8% ± 0.8% in vaccinated and challenged fish groups, respectively. Furthermore, the level of protection observed in the field trial closely resembled that achieved on a laboratory scale. Therefore, EC-killed showed the highest molecular weight 31 kDa in SDS-PAGE and Western blot and increased RPS (91%), suggested that the EC-killed cells of S. iniae could play an important role in immunizing mono-sex Nile tilapia. The EC-killed cells of S. iniae will may safe and long-lasting protection against streptococcosis.

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