Hemolytic activity of alternative complement pathway as an indicator of innate immunity in pacu (Piaractus mesopotamicus)

Abstract

-The objective of this study was to evaluate the methodology to establish the hemolytic activity of alternative complement pathway as an indicator of the innate immunity in Brazilian fish pacu (Piaractus mesopotamicus), in addition to verifying the influence of β-glucan as an immunostimulant. Fish were fed with diets containing 0, 0.1 and 1% β-glucan, during seven days, and then inoculated with Aeromonas hydrophila. Seven days after the challenge, they were bled for serum extraction. The methodology consisted of a kinetic assay that allows calculating the required time for serum proteins of the complement to promote 50% lysis of a rabbit red blood cell suspension. The method developed in mammals was successfully applied for pacu and determined that the hemolytic activity of the proteins of the complement system (alternative pathway) increased after the pathogen challenge, but was not influenced by the β-glucan treatment.

The immune system is limited by oxidative stress: Dietary selenium promotes optimal antioxidative status and greatest immune defense in pacu Piaractus mesopotamicus

“…For this assay, samples of 200 mL serum dilution from each treatment condition were mixed with a 400-mL suspension of red blood cells. Absorbance was read for 10 min at 700 nm in a spectrophotometer in a 25 C waterbath, with modifications proposed by Biller-Takahashi et al [38].…”

Reproductive Behaviour, Hematological Profile and Monogenean Microfauna of the Nest-Breeding, Nile Green Tilapia (Tilapia zilli) Gervais, 1848

“…Many studies indicated that fish thrombocytes are blood phagocytes, which form an important tool of the protective barriers in fish (e.g. [43,44]) Significantly higher levels (counts) of the blood thrombocytes of the breeding forms of the green tilapia seem likely to represent an immune response and a healing process following frequent injuries induced by invaders of the nesting arenas such as antagonistic, non-breeding males of the cichlid fish and the freshwater carb, Liocarcinusvernalis and the crayfish,Procambarusclarkii.…”

Supplementation with arginine in the diet of Nile tilapia reared in net cages

“…Indicators of the innate immune system were also evaluated, such as leukocyte respiratory activity and complement pathway protein activity, according to the method described by Biller-Takahashi et al (2012.…”