Effect of dietary β-1,3-glucan on resistance to white spot syndrome virus (WSSV) in postlarval and juvenile Penaeus monodon

Abstract

This study evaluated the effectiveness of dietary incorporation of P-1,3-glucan from SchizophyUum commune in enhancing the resistance of postlarval (PL15) or juvenile (5.5 * 0.5 g ) Penaeus monodon to white spot syndron~e virus (WSSV). The shrimp were fed experimental diets with (2 g kg-' diet) or without P-1,3-glucan for 15 d (postlarvae) or 10 or 20 d (juveniles). Following these dietary treatments, the postlarvae were challenged by imrnerslon and the juveniles by injection using WSSV solution. After challenge with WSSV, initial mortality was significantly (p < 0.005) lower in all the glucan-fed groups than in the respective non-glucan control groups. In the juvenile groups, glucan supplementation for 20 d rather than 10 d significantly (p < 0.005) enhanced survival. After the WSSV challenge, none of the control diet postlarvae or juveniles survived beyond 4 d and none of the 10 d glucan-fed juveniles survived beyond 6 d. By contrast, some of the glucan-treated postlarvae (12.2%) and some of the 20 d glucan-treated juveniles ('OX,) were still alive at Day 6. These surviving individuals were reared onwards up to 120 d post-challenge, at which tlme overall survivals were 5.5% (postlarvae) and 13.3% (juveniles) and body weights were 25 to 30 g (postlarvae) and 30 to 40 g (juveniles). Half of the surviving postlarvae and 58% of the surviving juveniles were 2-step WSSV polymerase chain reaction (PCR) negative 6 d after challenge. All the surviving shrimp were 2-step WSSV PCR negative 120 d after challenge.

Influence of selected Indian immunostimulant herbs against white spot syndrome virus (WSSV) infection in black tiger shrimp, Penaeus monodon with reference to haematological, biochemical and immunological changes

“…Haemocytes are responsible for clotting, exoskeleton hardening and elimination of foreign materials [27]. Mean THCs of healthy penaeid shrimps ranged from 20 to 40 Â 10 6 cells ml ÿ1 [20]. Molting, development of organs, reproductive status, nutritional condition and disease have been shown to influence haemocyte abundance [29].…”

“…The DNA extraction and PCR amplification followed the method described by Chang et al [20]. Different organs such as head tissue, eye stalk, gills and tail muscle of experimental and control shrimps (AeE) were tested by first step PCR.…”

Dose/frequency: A critical factor in the administration of glucan as immunostimulant to Indian white shrimp Fenneropenaeus indicus

“…The most active of these compounds is (1-3)-β-D-glucan (Bhon and Be Miller, 1995), a natural polymer isolated from the cell wall of yeast and mold. β-glucans have been used as immunostimulants to enhance the defence potential of fish and shellfish against bacterial or viral infection (Oliver et al, 1986;Sung et al, 1994;Song et al, 1997;Chang et al, 1999Chang et al, , 2000Chang et al, , 2003. Currently many commercial immunostimulants are available in the shrimp aquaculture industry and are extensively used by shrimp farmers.…”

Protection against white spot syndrome virus (WSSV) infection in kuruma shrimp orally vaccinated with WSSV rVP26 and rVP28

“…A low level of protection against WSSV challenge was observed in the control shrimp that were orally vaccinated with E. coli proteins, with a 54% RPS following oral WSSV challenge and 22% by immersion challenge (Table 3). We believe this low level of WSSV protection suggests that the E. coli proteins might have an immunostimulatory effect on the shrimp as in previous studies , Chen et al 1999, Sritunyalucksana et al 1999. Wu et al (2002) reported that resistance to WSSV in shrimp that survived WSD appeared 3 wk after primary infection and persisted for about 2 mo.…”