PAQ-Xtract^®: Quillaja Saponaria Extract in the Control of Intracellular Bacteria in Salmon

The SRS Case

One of the main infectious diseases caused by a facultative intracellular gram-negative bacteria (Piscirickettsia salmonis) is Piscirickettsiosis (salmonid rickettsial septicemia or SRS), responsible for significant economic losses in the salmon industry.

Among the main strategies that P. salmonis uses as a facultative intracellular bacteria to generate its systemic infection, is to infect, survive and reproduce within cells of the innate immune system with phagocytic capacity, such as macrophages (Mccarthy et al. al, 2008), circumventing the host’s immune response (Perez-Stuardo, et al, 2019; Rozas-Serri et al, 2018; Labra et al, 2016; Fernández et al, 2006).

Taking into account that the control of Piscirickettsiosis is a complex task, that optimizing the use of antibiotics in the salmon industry is essential to counteract the development of bacterial resistance, that some of the strategies used so far do not induce the expected effectiveness, and that it is necessary to complement the work done by vaccines, nutritional additives and genomic selection, the current challenge remains the development of new non-pharmacological solutions to prevent and control Piscirickettsia salmonis infections in the salmon industry.

A non-pharmacological alternative that can increase resistance to diseases and reduce the impact of Piscirickettsiosis in salmonids, by modulating the innate and adaptive immune response, are the highly purified extracts of Quillaja saponaria Mol (Paq-Xtract), rich in triterpenoid saponins. (Marciani, 2018; Maier et al, 2015; Kensil et al, 1991) and that when administered orally, have demonstrated beneficial effects to increase resistance to diseases, and improve nutrient utilization in both aquaculture and terrestrial species ( Wang et al, 2016; Ng’ambi, 2016; Naknukool et al, 2011; Cheeke et al, 2005; Francis et al, 2005; Ninomiya et al, 1995).