Kappa-Carrageenan as an Immunostimulant for Infectious Myonecrosis (IMN) Disease Control on Whiteleg Shrimp Litopenaeus vannamei

Abstract

The modulation on nonspesific immune response, growth and disease resistance of Litopenaeus vannamei against IMNV was aimed on this studied. Briefly, the experiment had comprised two stages. The first stage studied dose of k-carrageenan administration at rate 5, 10, and 15 g kg-1 feed for 4 weeks rearing, while the later studied about frequency of administration of the best outcoming dose including daily, 7 days interval, and 14 days interval administration for 5 weeks rearing. Both of stages had positive and negative control, and done in complete randomized design where the performance based on dynamic of immunity and shrimp growth were measured during rearing, while survival rate, clinical signs and histophatology were observed after challenged. Shrimp were fed three times a day at feeding rate of 4-5% of body weight day-1. Challenge test was performed by mean feeding the shrimp with IMNV via oral route at rate 10% of body weight during 3 consecutive days, than observed for 14 days. The results showed that shrimp which administered with k-carrageenan at rate of 15 g kg-1 feed had best performance than other aplications. The shrimp’s hemocyte count, phagocytic activity, phenoloxidase activity, and relative growth were 12±0,72 x 106 cell ml-1; 34,67±0,58%; 0,511±0,10 and 86.15% respectively. After challenged, the survival rate was 85±7.07%. Moreover, in the next stage work, aplication in 14 days interval gave 88.57% in relative growth and 93±5,8% in survival rate, higher than other aplications. They were confirmed by visual gross sign and histopathology that appeared as well as PCR test. Then, it was concluded that, the administration of k-carrageenan at rate 15 g kg-1 and present in 14 days interval had better immunostimulatory effect to enhance nonspesific immune response and elevate disease resistance of whiteleg shrimp juveniles against IMNV.