BENEFICIAL IMPACTS ON IMMUNE RESPONSES AND DISEASE RESISTANCE OF WHITELEG SHRIMP (Litopenaeus vannamei) FED DIETARY HERBAL EXTRACTS

The present study was conducted to determine the effective herbal extracts of Phyllanthus urinaria and Combretum quadrangulare incorporated into the diets on the health of whiteleg shrimp (Litopenaeus vannamei). A commercially available feed diet was incorporated with a concentration of 1% P.urinaria, 1% C.quadrangulare,1% of a mixture of both 1% P. urinaria and 1% C. quadrangulare Kurz (experimental diets), and no herbal extract (control treatment). Shrimps (1.05±0.33 g) in triplicate groups were fed with the supplemented diets for 4 weeks in a 500 L tank with a stocking density of 70 shrimp/tank. Hematological and immunological parameters (Total hemocyte count, granular cells, hyaline cells, phenoloxidase activity-PO, and immune gene expressions) were evaluated after the feeding trial. The results showed that after 4 weeks of dietary herbal supplementation of 1% P. urinaria (PUE), and 1% mixture of P. urinaria and C. quadrangulare (PUE-CQE) significantly enhanced hematological and immunological parameters (total hemocyte count, granular and hyaline cells, phenoloxidase, lysozyme, and Penaeidin-3). After being challenged against V. parahaemolyticus, cumulative mortality of shrimp in treatment of a 1% mixture of P. urinaria and C. quadrangulare (PUE-CQE) was lower compared to the positive control at 43.6% and 66.7% respectively and the difference was statistically significant (p<0.05). Dietary herbal-supplemented treatments of 1% CQE and 1% PUE were slightly lower than the positive control at 55.6% and 59.5% respectively hence no significant difference (p>0.05). This shows that all the herbal treatments lowered the susceptibility and increased protection against V. parahaemolyticus compared to the positive control. In summary, the results indicate that P. urinaria and C. quadrangulare dietary herbal extracts have beneficial impacts on immune responses and disease resistance in whiteleg shrimp (Litopenaeus vannamei) against V. parahaemolyticus.