Vitamin E is an efficient antioxidant and a modulator of the immune system. Although racial differences in both baseline vitamin E level and immunologic subsets are known, no reliable data exist for the Asian population. Furthermore, the extent of the effect of alpha-tocopherol in protecting lymphocyte cells against oxidative stress and its association with cell-mediated immunity have not been elucidated. This study was undertaken to investigate the immunologic and antioxidant effects of vitamin E in healthy ethnic Chinese men and women. Volunteers < 35 y old (n = 26) were supplemented with 233 mg/d dl-alpha-tocopherol for 28 d. The in vitro proliferative response to phytohemagglutinin (PHA) or lipopolysaccharide (LPS) of T-lymphocytes was determined in the study group before and after vitamin E supplementation. Cell-mediated immunity subsets and hydrogen peroxide production in T-lymphocytes were investigated by flow cytometry. The oxidant-antioxidant balance in plasma and urine was studied by spectrophotometric and gas chromatography-mass selective detection methods. The antioxidant properties of vitamin E were established (P: < 0.01) by the elevation of plasma vitamin E, together with depression in both plasma malondialdehyde and urinary DNA adduct 8-hydroxy-2'-deoxyguanosine after supplementation. Our data suggest a specific requirement for vitamin E in total-T and T-helper cell proliferation. We present the first evidence of the beneficial effects of supplemental vitamin E in healthy Chinese individuals on cell-mediated immunity and oxidative stress.

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The study was conducted to evaluate the extruded and pelleting feed production on growth performance, intestinal histology and microbiome analysis of juvenile red swamp crayfish, Procambarus clarkii. Crayfish were fed either pelleted or extruded feeds that were made using the same formula. Crayfish fed extruded feed had a lower feed conversion ratio, as well as significantly higher levels of trypsin and amylase (p < 0.05) than those fed pelleted feed. However, other growth indices and the activity of lipase were not significantly influenced by the feed processing technique (p > 0.05). In comparison with the pelleted feed group, the lamina propria thickness of crayfish fed extruded feed was significantly lower (p < 0.05). Additionally, the abundance of intestinal microbiota in the extruded feed group was higher than that in the pelleted feed group. The dominant phyla in the intestine of both groups were Proteobacteria, Tenericutes, and Firmicutes, and the relative abundance of Proteobacteria in the extruded feed group was significantly higher than that in the pelleted feed group (p < 0.05). These results revealed that P. clarkii fed extruded feed had higher feed utilization and better intestinal health.

We evaluated the effect of vitamin C (Vit C) supplementation on the resistance of Megalobrama amblycephala to Aeromonas hydrophi1a infection under pH stress. Fish were randomly divided into six groups: a control group (fed with a basal diet) and five treatment groups (fed with basal diet supplemented with 33.4, 65.8, 133.7, 251.5 and 501.5 mg/kg Vit C, respectively). After 90 days, fish were exposed to combined stressors, first pH 9.5 followed by A. hydrophila infection. The results showed that 133.7 mg/kg vit C improved complement 4 (C4), anti-superoxide anion free aradical (ASAFER) and heat shock protein (HSP) 70 compared with the control group; and 251.5 mg/kg vit C enhanced complement 3 (C3), HSP60, HSP70 and HSP90 compared to the control group before stress. After pH stress and A. hydrophila infection, hemoglobin, ASAFER and HSP60, HSP70, HSP90 in the groups fed with 133.7 and 251.5 mg/kg vit C were still significantly higher, while serum cortisol in the group fed with 251.5 mg/kg vit C was lower compared to the control group 15 days after pH stress. The cumulative mortality of the control group was higher than that of the five treatment groups at 12, 24 h after A. hydrophila infection. The results of this study suggest that 133.7-251.5mg/kg vit C in a diet could have potential to stimulate immune response, and enhance resistance against high pH stress and A. hydrophila infection of Wuchang bream.

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This study was aimed to evaluate the effects of feeding frequency on growth performance, antioxidant status and immunity of juvenile red swamp crayfish Procambarus clarkia (average weight: 3.01±0.02 g). Crayfish were randomly assigned to one of five feeding frequencies (1,2,3,4 and 5 times/day, F1, F2, F3, F4 and F5) following the same ration size for 60 days. After the feeding trial, fish were challenged with white spot syndrome virus (WSSV) and cumulative mortality was recorded for the next 4 days. The results showed that the weight gain rate (WGR) of crayfish tended to increase initially and then decrease as feeding frequency increased. The WGR in F3 were significantly higher than those fed 1, 4 and 5 times/ day (P<0.05). The highest serum lysozyme (LZM), lowest catalase (CAT) and malondialdehyde (MDA) were observed in crayfish fed 3 times/day. However, there were no significant differences in cortisol, glucose (Glu), and superoxide dismutase (SOD) among all groups (P>0.05). The cumulative mortality in F3 was significantly lower than that of the other groups at d4 after challenge (P<0.05). In conclusion, both low and high feeding frequencies could cause stress of juvenile Procambarus clarkia and the optimal feeding frequency to enhance growth and immunity of this species at juvenile stage is 3 times/day.