Essay: Issues affecting prawn aquaculture

The giant freshwater prawn Macrobrachium rosenbergii is an economically important farmed inland crustacean species of the family Palaemonidae. This species inhabits a wide range of salinity levels during its life cycle and is found in waters ranging from 0 to 18 ppt. (Nelson et al., 1977). The giant freshwater prawn, M. rosenbergii (de Man), has commanded significant attention in tropical freshwater aquaculture research and development. The characteristics that make the culture of this species attractive include breeding easily in captivity, high hatching rate, high quality meat and in many countries, high market value. However, the relatively low survival of larval and juvenile stages often prevents the development of full economic potential of this crustacean (New et al. 2010). The intensification of prawn aquaculture linked with deteriorated pond environment and resultant stress as well as poor quarantine in many prawn hatcheries and farms in West Indies, China, Taiwan, India, and Thailand have witnessed the epizootics of M. rosenbergii nodavirus (MrNV) (Arcier et al., 1999; W. Cheng & Chen, 1998; Sahoo et al., 2005; Sahul, Yoganandhan, Widada, & Bonami, 2004). In India, juveniles and adults of M. rosenbergii have been suffered a major setback due to occurrence of appendage deformity syndrome (ADS) (Sahoo et al., 2005) and several disease outbreaks have occurred due to bacterial pathogens’ (Chen et al., 2001; Phatarpekar et al., 2002) such as Vibrio spp., ‘Aeromonas spp., and Pseudomonas spp., and Lactococcus garviae infection (Winton Cheng & Chen, 2000) which caused high mortalities in hatcheries (Delves-Broughton & Poupard, 1976; H. H. Sung et al., 2000; Tonguthai, 1995). Among, Aeromonas spp. is considered to be the major threat to the commercial cultivation of M. rosenbergii aquaculture in Taiwan (H.-H. Sung et al., 2000) and Brazil (J. V. Lombardi & V. L. Labao, 1991a) including India (Chand et al., 2006; K. V. Lalitha & P. K. Surendran, 2006; P. K. Sahoo et al., 2007; R. Shankar et al., 2011). The majority of the freshwater prawn mortality can be attributed to the involvement of pathogenic bacteria (Hoa et al. 2000; Scan 2003; Keysami et al. 2007). In the prawn aquaculture industry, Aeromonas hydrophila infection is considered a major cause of shell diseases and low rate of survival (Lightner & Redman, 1998; H.-H. Sung et al., 2000). Several studies have been reported that the application of herbal or other immunostimulants in fish and shrimp farming for enhancing immune response and reduction of disease impacts (G. Balasubramanian, Sarathi, Venkatesan, Thomas, & Sahul Hameed, 2008; Chand et al., 2006; R. Harikrishnan, C. Balasundaram, & M. S. Heo, 2011; R. Harikrishnan, C. Balasundaram, S. Jawahar, & M. S. Heo, 2011; B. Liu et al., 2010; R. Shankar et al., 2011). The potential immunostimulating properties of natural and commercial plant-derived products were evaluated for immunostimulation purpose in finfish and shellfish aquaculture against viral and bacterial diseases (G. Balasubramanian et al., 2008; Harikrishnan, Balasundaram, & Heo, 2011; Harikrishnan, Balasundaram, Jawahar, et al., 2011). The use of antibiotics to prevent these diseases has normally ‘been practiced in many cases although their indiscriminate use has led to increase in antibiotic resistance and residual level in the products (Plumb & Hanson, 2011; Sorum & Sunde, 2001; Vasudevan, 2000). While vaccines are specific for pathogen, thus novel strategies to control Aeromonas spp. in prawn culture are needed:
– To prevent and control prawn diseases
– Reduce stress and associated diseases outbreak
– Reduce potential human risk
– Decrease cost of rearing
– Using novel and friendly environment strategy
– Sustainable prawn production
In this study attempt using of oral OMPs vaccine at the rate of 25, 50, 75 and 100 ??g/kg body weight. The effect of OMPs vaccine on innate immune parameters, that was investigated in M. rosenbergii against A. hydrophila infection including:
i. Total haemocyte count (THC)
ii. Phenoloxidase activity (PO)
iii. Bacterial clearance efficiency
iv. Superoxide anion protection (O2_)
v. Superoxide dismutase activity (SOD)
vi. Relative percent survival (RPS)