Efficacy of orally administered kappa-carrageenan to enhance nonspecific immune responses and resistance of african catfish Clarias sp. against Aeromonas hydrophilla

Abstract

A study to evaluate the role of k-carageenan in varying dose to prevent A. hydrophilla infection was conducted. Experiment comprised by two stages. The first stage which to obtain the best dose, had performed by suplementation the k-carageenan at rate 5 g/kg, 10 g/kg, 20 g/kg of fish feed, and control. After four weeks rearing all fish except in negative group was chalenged by A. hydrophilla with consentration 108 cfu/fish that performed by means intramusculary injection. The best dose then determined according to survival and hematology assay of fish. The second stages studied about efficacy of duration administration at daily, seven days, 14 days, and 21 days of the best outcoming dose, where the efficacy determined through the growth rate and survival rate of fish during14 days post-infection. The results showed that fish in group 10g kg-1 had better performance compared to other chalenged group. The value of suvival rate, total haemoglobin, hematocrite, eritrocyte count, leucocyte count, and phagocytic activity were 95,83%; 10,40±1,25 g%; 33,47±1,47%; 2,19±0,06 (106 cell/mm3); 14,47 ± 0,96 (105 sel/mm3); and 16,35 ±1,10% respectively. Moreover, even not support survival rate of fish at best (only 71%, lower than 80% at 21 days treatment), application at 14 days had considered as the best duration administration due to it’s support to the growth rate of fish at best (28g) when compared to others. Then, it was conclude that administration at rate 10 g/kg in combination with 14 days application, had better effect to elevate the immune system of catfish.