Dietary fulvic acid effects on survival and expression of immune-related genes inLitopenaeus vannameichallenged withVibrio parahaemolyticus

Abstract

The effects of fulvic acid (FA) on survival and immune-related gene expression were investigated in Litopenaeus vannamei challenged with Vibrio parahaemolyticus by immersion. Shrimp were fed with different dietary FA concentrations (1, 2, 4 and 6 g/kg feed) for 20 days (first bioassay) or 8 days (second bioassay, 2 g/kg feed of FA added every 2 days) and then challenged with V. parahaemolyticus. In a third bioassay, the expression of three immune-related genes (translationally controlled tumour protein [TCTP], superoxide dismutase [SOD] and heat-shock protein 70[HSP70]) in haemocytes or hepatopancreas of experimental shrimp was measured by real-time quantitative PCR at 0, 6, 12, 24, 48, 72 and 96 hr after FA (2 g/kg feed) administration. Fulvic acid increased survival at a concentration of 2 g/kg feed supplied every two days. Interestingly, TCTP gene expression was upregulated, whereas gene expression of SOD and HSP70 was downregulated. In conclusion, dietary fulvic acid improves survival in white shrimp challenged with V. parahaemolyticus and modulates the immune response. Therefore, FA merits further evaluation as prophylactic treatment in commercial shrimp farms. K E Y W O R D SAHPND, fulvic acid, gene expression, Litopenaeus vannamei, Vibrio parahaemolyticus

Effects of Chitosan–Gentamicin Conjugate Supplement on Non-Specific Immunity, Aquaculture Water, Intestinal Histology and Microbiota of Pacific White Shrimp (Litopenaeus vannamei)

“…However, the excessive or inappropriate use of antibiotics may increase the prevalence of multi-drug-resistant strains, environmental pollution, and residue accumulation. In response to these concerns, alternative strategies have been proposed, including plant extracts [ 7 , 8 ], probiotics [ 4 , 9 ], polysaccharides [ 10 , 11 ], and other feed supplements [ 12 , 13 ]. However, these strategies are ineffective; once the Vibrio break out, the shrimps will still die in large numbers.…”

Phenol-rich fulvic acid as a water additive enhances growth, reduces stress, and stimulates the immune system of fish in aquaculture

“…Beneficial effects of HS, when used as feed additives, include growth stimulation, reduced mortality, accelerated recovery after diseases, and stimulation of immune-related genes [15][16][17][18] . However, negative or contradictory effects are reported as well, including genotoxicity in blood lymphocytes, oxidative stress, and reduced offspring in Daphnia magna [19][20][21] .…”

Effect of dietary C‐Phycocyanin on growth, survival, haematology, immune response, gut microbiome and disease resistance of Pacific white shrimp, Penaeus vannamei

“…In the present study, SOD gene levels in the CPC fed shrimps were not different from control except for CPC 800 in pre‐and post‐challenged shrimps and CPC 200 in post‐challenged shrimps, which might be due to decreased oxidative stress and free radical activities for the maintenance of superoxide anion levels during the feeding trial. In contrast, the inclusion of astaxanthin (Wang et al, 2015) or fulvic acid (FA) significantly improved SOD activity in the Chinese shrimp P. chinensis (Zhao et al, 2001) and modulated the immune response in P. vannamei (Fierro‐Coronado et al, 2018). The decrease in SOD mRNA levels observed in CPC 800 could indicate the decreasing superoxide anion (O 2 − ) and hydrogen peroxide (H 2 O 2 ) levels, indicating a decline in ROS production.…”