In vitro and in vivo immunologic potentiation of herb extracts on shrimp (Litopenaeus vannamei)

In vitro and in vivo effects of Astragalus polysaccharide (APS), chlorogenic acid (CGA) and berberine (BBR) on shrimp (Litopenaeus vannamei) were studied. In vitro test showed that the combination of APS and BBR and the combination of APS and CGA have strong immune enhancement effects and no lysosomal membrane damage on hemocyte. Then, feeding experiment was proceeded to optimize the concentrations of compound herbal extracts. Four diets containing G1-G4(0.5 g kg ^-1 APS + 0.5 g kg ^-1 BBR, 1.0 g kg ^-1 APS +1.0 g kg ^-1 BBR, 0.5 g kg ^-1 APS +0.5 g kg ^-1 CGA, 1.0 g kg ^-1 APS + 1.0 g kg ^-1 CGA) associated with the control group (common diet) were compared and determined their biomolecule damage to hepatopancreas including DNA damage, lipid peroxidation and protein carbonyl. The results indicated that G3 (0.5 g kg ^-1 APS +0.5 g kg ^-1 CGA) showed higher total hemocyte counts, phagocytic activities, antibacterial activities and bacteriolytic activities during 6 days feeding, and without biomolecule damages after 6 days post-withdrawal. Therefore, the appropriate immunostimulants formula in this study was the combination of 0.5 g kg ^-1 APS and 0.5 g kg^-1 CGA, which was used for 6 days followed by 6 days post-withdrawal. Additionally, our study provides new support for screening composite immunostimulants formula by using primary shrimp hemocyte culture.

Toxic responses of swimming crab (Portunus trituberculatus) larvae exposed to environmentally realistic concentrations of oxytetracycline

Oxytetracycline (OTC) is the most commonly used antibiotics for bacterial treatment in crustacean farming in China, and because of their intensive use, the potential harmful effects on aquatic organisms are of great concern. The aim of this study was to investigate the effects of oxytetracycline (OTC) on the antioxidant system, detoxification progress, and biomolecule damage in Portunus trituberculatus larvae. In this study, larvae that belonged to four zoeal stages were exposed to four different concentrations of OTC (0, 0.3, 3, and 30 μg/L) for 3 days. The results showed that the exposure to OTC significantly suppressed the antioxidant system of, especially, zoea I (Z1) and zoea II (Z2) larvae. OTC inhibited the transcriptional expression of phase I (CYP2 and CYP3) and phase II detoxification genes (GST) in a dose-dependent manner and altered the expressions of their corresponding enzymes, namely, aminopyrine N-demethylase, erythromycin N-demethylase, and glutathione S-transferase. Moreover, 0.3 μg/L OTC activated the transcription of ATP-binding cassette (ABC) transporter subfamily B (ABCB) and subfamily G (ABCG) in the Z1 and Z2 larvae, while 3 and 30 μg/L OTC suppressed all of them. Additionally, malondialdehyde content exhibited a dose- and zoea-effect relationship to some extent, but no significant differences were observed in the F values of the Z3 and Z4 larvae, except for the 30 μg/L OTC treatment. Thus, the Z3 and Z4 larvae were less sensitive to OTC exposure than the Z1 and Z2 larvae.