A new study out of Brazil’s São Paulo University suggests daily supplementation with the ancient plant aloe vera could be used naturally improve the immunity of farm-raised pacu fish.
Professors were mainly interested in whether aloe vera had any effect reducing the pacu’s reaction to the bacteria Aeromonas hydrophila, which often causes diseases in fish. They were also curious to see if the aloe vera plant strengthened the pacu fish’s immune response to travel stressors.
In total, researchers examined 240 young pacu fish who were split up into four different groups. The control group was only given a standard diet without aloe vera extract. The other three groups were given 5, 10, or 20 grams of aloe vera spray in their commercial feed every day.
After ten days, scientists packed the fish up and sent them on a four-hour drive to another facility. Researchers then took blood samples of all the fish to see how they fared with the added stress of travel. They also injected a few fish with a placebo and others with the A. hydrophila bacteria to see if aloe vera had any positive effect.
When they examined the blood samples of the four groups of fish, researchers found that the aloe vera groups had a stronger immune system than the control group. They also found that fish who had aloe vera had a lower amount of the stress hormone cortisol in their bloodstream than the control group.
Researchers hope this study will encourage people working in aquaculture to consider using natural remedies like aloe vera to combat travel stress and bacterial infections rather than harsh antibiotics.
Fábio S. Zanuzzo, who works at São Paulo University’s Aquaculture Center of Unesp, was the lead author on this study. This study was recently published in Fish & Shellfish Immunology under the title, “Aloe vera enhances the innate immune response of pacu (Piaractus mesopotamicus) after transport stress and combined heat killed Aeromonas hydrophila infection.”