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Selenium (Se) is an essential trace element for humans and animals. Stropharia rugoso-annulata is a nutritional and functional mushroom containing many kinds of bioactive ingredients. The aims of this study were to investigate the Se-enrichment characteristics of S. rugoso-annulata in submerged culture and evaluate the antioxidant activities of Se-enriched mycelia in vivo in terms of the values of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and malondialdehyde (MDA). The optimum parameters of Se-enrichment under the optimal Se concentration (150 microg/mL) in media were as follows: biomass 8.11 +/- 0.25 g/L, Se content in mycelia 4,727.68 +/- 13 microg/g, Se-accumulated rate 24.68 +/- 1.67%, and percentage of organic Se 96.27 +/- 3.26%. The mainly subsistent forms of selenium in Se-enriched mycelia were selenoprotein and selenium-polysaccharide. The contents of total amino acids (TAA) and essential amino acids (EAA) in Se-enriched mycelia were increased by 13.5 +/- 1.09% and 12.8 +/- 0.89%, respectively. It was efficient for Se-enriched mycelia to elevate GSH-Px and SOD activities and decrease MDA content. These results indicated that Se-enriched mycelia of S. rugoso-annulata represent a novel dietary source of bioavailable supplemental selenium.

Ninety-six thousand one-day-old AA broilers were randomly assigned to two groups, 5 replicates in each group, and 9,600 chickens for each replicate. In the control group, 0.3 part per million (ppm) inorganic selenium (Na 2 SeO 3) was added to the diets; while in the experimental group, 0.3 ppm organic selenium (Se-enriched yeast) was added to the same basal diets. The feeding experimental period was 42 days. The results show that: (1) Organic selenium could increase daily weight gain and feed intake by 8.92 (P<0.05) and 3.99% (P<0.05), and decrease survival rate and feed conversion by 0.93 (P<0.05) and 4.84% (P<0.05), indicating that the effects of organic selenium on broiler growth performance were better than that of inorganic selenium, except for survival rate. (2) Compared with the control, meat red color degree of chest and thigh muscles were increased by 13.98 (P<0.05) and 20.83% (P<0.05); the drip losses of chest and thigh muscles were decreased by 13.57 (P<0.05) and 24.92% (P<0.05), respectively. (3) Serum glutathione peroxidase (GPX) activity in experimental group were 155.83% higher than that in the control (P<0.05). These results indicate that the effects of organic selenium on enhancing body oxidation resistance were superior to that of inorganic selenium.

Response surface methodology (RSM) was successfully applied to investigate the effect of cultivation temperature, time and volume of media on mycelia growth, in the light of exopolysaccharide content (EPC) and dry cell weight (DCW), by the fungus Stropharia rugosoannulata in submerged culture. The three significant factors influencing EPC and DCW were based on the results of a previous Plackett-Burman (PB) design. Results showed that the maximum predicted values of EPC and DCW reached 1,498.17 mg l −1 and 9.89 g l −1 , while the optimized conditions of cultivation temperature, time and volume of media for EPC and DCW were 28.35°C, 6.67 days, and 110.29 ml, and 28.23°C, 6.58 days, and 109.17 ml, respectively. When the above conditions were 28.29°C, 6.63 days, and 109.69 ml, the simultaneously maximal yield of exopolysaccharide and mycelia biomass were 1,498.08 mg l −1 and 9.88 g l −1 , respectively. These predicted values were also verified by validation experiments.