Aloe vera enhances the innate immune response of pacu (Piaractus mesopotamicus) after transport stress and combined heat killed Aeromonas hydrophila infection

Abstract

In this study, pacu (Piaractus mesopotamicus) were fed with diets containing Aloe vera for 10 days prior to transport stress and infection with heat killed Aeromonas hydrophila. A. vera is popular around the world due to its medicinal properties, including immunostimulatory effects which was observed in this study. The results show that transport causes immunosuppression, an effect that was prevented by A. vera. Specifically, A. vera prevented reductions of both leukocyte respiratory burst and hemolytic activity of complement system caused by transport. Further, fish fed with A. vera also showed significantly higher leukocyte respiratory burst, serum lysozyme concentrations and activity of complement system 24 h after bacterial infection. Additionally, we observed that A. vera may modulate the innate response through activation of complement system during bacterial immune stimulation. In summary, A. vera extract enhanced innate immune parameters and consequently the ability of fish to cope with pathogens following transport stress. These findings show that A. vera has promise for use in aquaculture and add further evidence that medicinal herbs added to fish feed assist to prevent disease outbreaks.

Effect of dietary Aloe vera polysaccharides supplementation on growth performance, feed utilization, hemato-biochemical parameters, and survival at low pH in African catfish (Clarias gariepinus) fingerlings

“…Gabriel et al (2015a) reported the same in a GIFT strain O. niloticus fed 100% A. vera extracts. In addition, improved innate immune response after dietary A. vera supplementation was reported in matrinxa, Brycon amazonicus (Zanuzzo et al 2015b); whiteleg shrimp, Litopenaeus vannamei (Trejo-Flores et al 2016); and pacu, Piaractus mesopotamicus (Zanuzzo et al 2017).…”

The use of feed and water additives for live fish transport

“…Zanuzzo et al . () administered one of four diets (0%, 0.5%, 1% or 2% A. vera ) for 10 days prior to a 4 h transport of juvenile pacu ( Piaractus mesopotamicus, Holmberg 1887). Immediately following transport, the pacu were divided into three sub‐groups: a noninjected control group, a buffer injected group and a group injected with inactivated Aeromonas hydrophila (Chester 1901) to stimulate their immune system.…”

“…One study looked at A. vera as a dietary supplement prior to transport (Zanuzzo et al . ; see above) and an additional study by the same group used A. vera in the water during transport of fish. Zanuzzo et al .…”

“…Kim et al 1999;Taiwo et al 2005;Dotta et al 2014;Gabriel et al 2015a,b;Zanuzzo et al 2015a,b). One study looked at A. vera as a dietary supplement prior to transport (Zanuzzo et al 2017;see above) and an additional study by the same group used A. vera in the water during transport of fish. Zanuzzo et al (2012) dissolved A. vera powder (concentrations: 0, 0.02, 0.2 and 2 mg L À1 ) in the transport water of matrinxã (Brycon amazonicus, Spix and Agassiz 1829).…”

“…V azquez et al 1996; Reynolds & Dweck 1999;Vogler & Ernst 1999;Choi et al 2001;Choi & Chung 2003;Mahor & Ali 2016) but little is known about the benefits of using A. vera as a dietary supplement in aquaculture. Zanuzzo et al (2017) administered one of four diets (0%, 0.5%, 1% or 2% A. vera) for 10 days prior to a 4 h transport of juvenile pacu (Piaractus mesopotamicus, Holmberg 1887). Immediately following transport, the pacu were divided into three sub-groups: a noninjected control group, a buffer injected group and a group injected with inactivated Aeromonas hydrophila (Chester 1901) to stimulate their immune system.…”