Chlorophytum borivilianumPolysaccharide Fraction Provokes the Immune Function and Disease Resistance ofLabeo rohitaagainstAeromonas hydrophila
The present study aimed to investigate the effects ofChlorophytum borivilianumpolysaccharide (CBP), as a dietary supplement administered at varying concentrations with feed (basal diet), on various cytokine-related responses inLabeo rohitafingerlings. Immune parameters and immune-related gene expressions were measured at 3rd, 4th, and 5th week after feeding. The results revealed that dietary administration of CBP at 0.2% and 0.4% for 4 weeks significantly upregulated serum lysozyme and phagocytic activity. Complement C3 and respiratory burst activity (RBA) were significantly higher after 4 weeks of CBP feeding. The immune related genesIL-8,IL-1β,TNF-α, andiNOSwere downregulated (P<0.05) in groups with 0.2% and 0.4% CBP supplemented diets at week 4. Expression of anti-inflammatory cytokines (IL-10andTGF-β) was also downregulated (P<0.5) after 4 weeks of feeding with 0.2% to 0.8% CBP. However, five weeks of CBP administration had no significant effect on immune gene expression, exceptTNF-αandIL-8. Fish fed with 0.4% CBP for 4 weeks showed maximum resistance againstAeromonas hydrophila(73.3% survival) compared to control. From these results, we recommend that CBP administration at 0.4% for 4 weeks could effectively improve immune response and disease resistance inL. rohita.