Antibacterial activity of garlic (Allium sativum) againts Gram-positive bacteria isolated from tiger shrimp (Penaeus monodon)

Effect of dietary garlic (Allium sativum) on the zootechnical performance and health indicators of aquatic animals: A mini-review

Considerable efforts have been made by modern aquaculture to mitigate the environmental damages caused by its practices while also attempting to improve the quality of the aquatic organisms by promoting alternatives, such as the use of natural products, like garlic (Allium sativum), and instead of chemical agents. Garlic has multiple properties, including antifungal, antibacterial, antiviral, antitoxic, and anticancer effects. In fish, the antiparasitic activity of garlic is one of the most reported effects in the literature, mainly using immersion baths for aquatic organisms. Using garlic also has an antimicrobial effect on the culture of aquatic organisms. Therefore, this review focuses on the impact of garlic on the health and production of aquatic organisms.

Antibacterial activity of Oliveria decumbens against Streptococcus iniae in Nile tilapia (Oreochromis niloticus) and its effects on serum and mucosal immunity and antioxidant status

The aims of this study were to investigate the antibacterial, immunostimulatory and antioxidant properties of different derivatives of Oliveria decumbens, in vitro and in vivo. The GC-MS spectrometry analysis showed γ-terpinene as the most frequent compound in essential oil, whereas carvacrol and thymol were the most common ones in aromatic water. Plant essential oil and hydroethanolic extract showed a positive in vitro bactericidal activity against Streptococcus iniae as evaluated by disc diffusion, minimum inhibitory concentration and minimum bactericidal concentration methods. Also, in vivo resistance against S. iniae and immune and antioxidant responses of Nile tilapia (Oreochromis niloticus) were assayed after 60 days treatment with O. decumbens derivatives. Plant hydroethanolic extract and essential oil and their 1:1 combination were added to diet at 0 (negative control), 0.01, 0.1 and 1% (w:w). The plant aromatic water at doses of 0.0312, 0.0625 and 0.1250% were also used as bath treatment. The results showed that aromatic water at lowest dose was more effective than other treatments in increment of fish resistance against S. iniae (7.14% mortality in comparison with 50% mortalities in control fish) and modulation of post-challenge respiratory burst activity. The bactericidal activity and biochemical contents of skin mucus did not change significantly among treatments. The levels of superoxide dismutase and catalase antioxidant enzymes activities in spleen tissue were significantly higher in treatments received extract, essential oils and their combination in comparison to other groups, while treatments did not affect peroxidase level. In conclusion, administration of different derivatives of Oliveria decumbens showed remarkable antibacterial activity against streptococcosis and enhanced antioxidant status and post-challenge immunity in Nile tilapia.