摘要
Selenium protects cells from oxidative damage and reduces lipopolysaccharide （LPS）-induced expression of inflammatory cytokines. Because inflammatory cytokines induce growth depression, we hypothesized that selenium-rich yeast （SeY） would inhibit growth depression caused by LPS. Twenty Meishan weanling pigs [28 （s.d. 2 d）, 7.6 （s.d. 0.3 kg） body weight （BW）] were used in a 2×2 factorial design （n=5）. The main factors were dietary Se sources [selenium-rich yeast （SeY） vs. sodium selenite （SSe）] with supplement level at 0.3 mg Se/kg, and immunological stress （LPS vs. saline）. The experiment lasted for 28 d. On d 14 and d 21, half of pigs in each dietary treatment were intramuscularly injected with either 50 μg/kg BW LPS or an equivalent amount of sterile saline. Blood samples were collected at 3 h post-injection. There were no interactions between dietary Se sources and immunological stress on growth performance. LPS depressed average daily gain （ADG） （d 14-21, P〈0.05; d 21-28, P〈 0.01）, and elevated feed to gain ratio （F/G） （d 21-28, P〈0.05）, while SeY elevated ADG （d 0-14, P〈0.05; d 21-28 and d 0-28, P〈0.01）, and decreased F/G （P〈0.01）. Interactions were observed on interleukin-1β（IL-1β） and interleukin-6 （IL-6） from serum samples of d 14 and d 21 （P〈0.01）, as well as superoxide dismutase （SOD） and insulin like growth factor （IGF-1） of d 21 （P〈0.05）. In conclusion, SeY relieved the growth depression of piglets immunologically stressed by LPS, which maybe resulted from the decreased externalization of inflammatory cytokines and improved antioxidant status.
