Institute of Animal Science, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China.
Biol Trace Elem Res. 2018 Feb;181(2):251-257. doi: 10.1007/s12011-017-1064-5. Epub 2017 Jun 3.
Iodine (I) is an essential trace element that can influence animal health and productivity. In this study, we investigated the effects of dietary iodine on the antioxidant indices of organ (liver and thyroid gland) and messenger RNA (mRNA) expression of glutathione peroxidase (GSH-Px) in Rex rabbits. A total of 120 4-month-old Rex rabbits (2235.4 ± 13.04 g BW) were divided into four equal groups, and their diets were supplemented with iodine (0, 0.2, 2, or 4 mg/kg dry matter (DM)). The iodine concentration in basal diet (control group) was 0.36 mg/kg DM. In most of measured parameters, supplemental iodine exerted no significant effect. Growth and slaughter performance and organ weight were not influenced significantly by iodine supplementation. Serum T was significantly lower in 2-mg I group than in 0.2 and 4-mg I groups (P < 0.05). Superoxide dismutase (SOD), GSH-Px, methane dicarboxylic aldehyde (MDA), and thyroperoxidase (TPO) in the serum and liver were not influenced (P > 0.05). Conversely, serum catalase (CAT) was significantly reduced (P < 0.05). In the thyroid, GSH-Px was higher in the 2-mg I group than in the 0.2- and 4-mg I groups (P < 0.05). RT-PCR results showed that the mRNA expression level of GSH-Px in the liver was not significantly influenced (P > 0.05). In the thyroid gland, the mRNA expression level of GSH-Px was higher in the 2-mg I group than in the 4-mg I group (P < 0.05), which agreed with the activity of GSH-Px. In conclusion, iodine supplementation exerted no effect on the performance and antioxidant capacity of the body, but dietary iodine influenced serum T or GSH-Px in the thyroid gland. Thus, on the basis of serum T and GSH-Px levels in the thyroid gland, we hypothesized that GSH-Px secretion was increased by adding dietary iodine in the thyroid, which may inhibit the HO generation and further influence the thyroid hormone synthesis.
碘（I）是一种必需的微量元素，可影响动物的健康和生产力。本研究旨在探讨饲粮碘对 Rex 兔器官（肝脏和甲状腺）抗氧化指标及谷胱甘肽过氧化物酶（GSH-Px）信使 RNA（mRNA）表达的影响。将 120 只 4 月龄 Rex 兔（2235.4±13.04gBW）随机分为 4 组，每组 30 只，分别饲喂基础饲粮（对照组）和添加 0、0.2、2 或 4mg/kg 干物质（DM）碘的试验饲粮。基础饲粮中碘含量为 0.36mg/kgDM。在大多数测定指标中，补碘均无显著影响。生长性能、屠宰性能和器官重量不受碘添加的显著影响。与 0.2 和 4mg/kg 碘组相比，2mg/kg 碘组血清 T 水平显著降低（P<0.05）。血清和肝脏中超氧化物歧化酶（SOD）、GSH-Px、甲烷二羧酸醛（MDA）和甲状腺过氧化物酶（TPO）活性无显著变化（P>0.05）。相反，血清过氧化氢酶（CAT）活性显著降低（P<0.05）。甲状腺中，2mg/kg 碘组 GSH-Px 活性显著高于 0.2 和 4mg/kg 碘组（P<0.05）。RT-PCR 结果显示，肝脏中 GSH-Px mRNA 表达水平无显著变化（P>0.05）。甲状腺中，2mg/kg 碘组 GSH-Px mRNA 表达水平显著高于 4mg/kg 碘组（P<0.05），与 GSH-Px 活性一致。综上所述，饲粮碘对 Rex 兔的生产性能和抗氧化能力无影响，但影响血清 T 或甲状腺 GSH-Px。因此，基于血清 T 和甲状腺 GSH-Px 水平，推测饲粮碘增加了甲状腺 GSH-Px 的分泌，抑制了 HO 的生成，进一步影响了甲状腺激素的合成。
