Selenium-enriched polysaccharide (SeEPS) was prepared by reducing Se(IV) to elemental selenium and organic selenium in polysaccharide medium by the obtained Enterobacter cloacae strain Z0206 under aerobic conditions. In the present study, we focused on investigating the role of short-term supplementation of SeEPS at supernutritional doses in the regulation of growth performance, liver damage, antioxidant capacity, and selenium (Se) accumulation in C57 mice. Thirty-two C57 mice were randomly divided into four groups: the control group was gavaged with equal volume of phosphate-buffered saline, while the sodium selenite (Na2SeO3), selenomethionine (SeMet), and SeEPS groups were gavaged with 0.5 mg Se/kg BW of Na2SeO3, SeMet, and selenium-enriched polysaccharide (n = 8), respectively. We examined liver injury indicators, antioxidant capacity in the serum and liver, selenium deposition at different sites, selenoprotein levels, and selenocysteine-synthesizing and degradation-associated gene expression in mouse livers. SeEPS supplementation dramatically increased average daily weight gain but reduced the feed-to-gain ratio (F/G) of mice (P < 0.05). Compared to Na2SeO3 and SeMet supplementation, SeEPS supplementation at supernutritional doses did not cause the liver damage. SeEPS supplementation also markedly enhanced total antioxidant capacity (T-AOC), catalase (CAT), glutathione peroxidase (GSH-PX), and total superoxide dismutase (T-SOD) activities but reduced malondialdehyde (MDA) levels in the liver and serum (P < 0.05), while significantly increasing selenocysteine-synthesizing and degradation-related gene (SEPHS2, SEPSECS, Secisbp, Scly) expression at the mRNA level (P < 0.05), thus upregulating the mRNA levels of selenoproteins (SELENOP, SELENOK) (P < 0.05). We suggest that SeEPS could be a potential replacement for inorganic selenium to improve animals' growth performance, promote antioxidant capacity, and regulate selenium deposition.

中文翻译：

---

富硒多糖：C57小鼠有效且安全的硒源，可改善生长性能、调节硒沉积并促进抗氧化能力。

将获得的阴沟肠杆菌Z0206菌株在有氧条件下，在多糖培养基中将Se(IV)还原为元素硒和有机硒，制备富硒多糖(SeEPS)。在本研究中，我们重点研究短期补充超营养剂量的 SeEPS 对 C57 小鼠生长性能、肝损伤、抗氧化能力和硒 (Se) 积累的调节作用。将 32 只 C57 小鼠随机分为 4 组：对照组灌胃等体积磷酸盐缓冲盐水，亚硒酸钠（Na2SeO3）、硒代蛋氨酸（SeMet）和 SeEPS 组灌胃 0.5 mg Se/kg分别为 Na2SeO3、SeMet 和富硒多糖 (n = 8) 的 BW。我们检查了肝损伤指标、血清和肝脏的抗氧化能力、不同部位的硒沉积、硒蛋白水平以及小鼠肝脏中硒代半胱氨酸合成和降解相关基因的表达。补充 SeEPS 显着增加了小鼠的平均每日体重增加，但降低了小鼠的料增比 (F/G)（P < 0.05）。与补充Na2SeO3和SeMet相比，补充超营养剂量的SeEPS不会引起肝脏损伤。补充 SeEPS 还显着增强总抗氧化能力 (T-AOC)、过氧化氢酶 (CAT)、谷胱甘肽过氧化物酶 (GSH-PX) 和总超氧化物歧化酶 (T-SOD) 活性，但降低肝脏和血清中的丙二醛 (MDA) 水平。 P < 0.05），同时在 mRNA 水平上显着增加硒代半胱氨酸合成和降解相关基因（SEPHS2、SEPSECS、Secisbp、Scly）的表达（P < 0.05），从而上调硒蛋白（SELENOP、SELENOK）的 mRNA 水平（P < 0.05）。我们认为 SeEPS 可以作为无机硒的潜在替代品，以改善动物的生长性能、提高抗氧化能力和调节硒沉积。