Immunostimulants for shrimp aquaculture: paving pathway towards shrimp sustainability

Abstract

At present, food security is a matter of debate of global magnitude and fulfilling the feeding requirement of > 8 billion human populations by 2030 is one of the major concerns of the globe. Aquaculture plays a significant role to meet the global food requirement. Shrimp species such as Litopenaeus vannamei, Penaeus monodon, and Macrobrachium rosenbergii are among the most popular food commodities worldwide. As per Global Outlook for Aquaculture Leadership survey, disease outbreaks have been a matter of concern from the past many decades regarding the shrimp aquaculture production. Among the past disease outbreaks, white spot disease caused by the white spot syndrome virus is considered to be one of the most devastating ones that caused colossal losses to the shrimp industry. Since the virus is highly contagious, it spreads gregariously among the shrimp population; hence, practicing proper sanitization practices is crucial in order to have disease-free shrimps. Additionally, in order to control the disease, antibiotics were used that further leads to bioaccumulation and biomagnification of antibiotics in several food webs. The bioaccumulation of the toxic residues in the food webs further adversely affected human too. Recently, immunostimulants/antivirals were used as an alternative to antibiotics. They were found to enhance the immune system of shrimps in eco-friendly manner. In context to this, the present paper presents a critical review on the immunostimulants available from plants, animals, and chemicals against WSSV in shrimps. Looking into this scenario, maintaining proper sanitation procedures in conjunction with the employment of immunostimulants may be a viable approach for preserving shrimp aquaculture across the globe.

Keywords: Antivirals; Eco-friendly; Food security; Immunostimulants; Shrimp sustainable aquaculture; White spot disease; White spot syndrome virus.

Fig. 1

Shrimp farming production by region. Courtesy-Global Seafood Alliance

Fig. 2

Immune system of shrimps

Fig. 3

Effects on antibiotics on shrimp aquaculture and environment

Fig. 4

Effects of vaccination on shrimp aquaculture

Fig. 5

Effects of immunostimulants on shrimp aquaculture and its environment

Fig. 6

Sources of immunostimulants

Fig. 7

Function of immunostimulants

Fig. 8

Mechanism of immunostimulation within shrimp body: the PAMP located on immunostimulants (IM) is recognized by PRP located on the hemocyte. This pattern recognition between IM and hemocyte activates the cascade of cellular signals that brings the shrimp’s body into a state of elevated immune response. When a pathogen enters shrimp’s body in such a state of aggravated immune response, then the PAMP of pathogen gets recognized by PRP of hemocyte, to cause phagocytosis, encapsulation, melanization, and nodule formation of the pathogen. All these immunological responses altogether eventually kill and decompose the pathogen

Fig. 9

Snieszko “epidemiological triad” and its application to shrimp health management