Immune responses and gene expression in white shrimp, Litopenaeus vannamei, induced by Lactobacillus plantarum.

The total haemocyte counts, phenoloxidase (PO) activity, respiratory bursts, superoxide dismutase (SOD) activity, and phagocytic activity and clearance efficiency to Vibrio alginolyticus, as well as prophenoloxidase (proPO), lipopolysaccharide- and beta-1,3-glucan-binding protein (LGBP), serine protein (SP), and peroxinectin (PE) mRNA transcription of L. vannamei, and its susceptibility to V. alginolyticus when the shrimp were fed diets containing Lactobacillus plantarum at 0 (control), 10(7), and 10(10) cfu (kg diet) (-1) for 48 and 168 h were evaluated. The results indicated that PO activity, SOD activity, clearance efficiency to V. alginolyticus, proPO and PE mRNA transcription, and the survival rate after challenge with V. alginolyticus all significantly increased, but the total haemocyte counts significantly decreased in shrimp fed a diet containing Lac. plantarum at 10(10) cfu (kg diet) (-1) for 168 h. However, no significant differences in phagocytosis, LGBP, or SP mRNA expression of shrimp were observed among the different treatments. It was concluded that administration of Lac. plantarum in the diet at 10(10) cfu (kg diet) (-1) induced immune modulation and enhanced the immune ability of L. vannamei, and increased its resistance to V. alginolyticus infection.