文献类型： 外文期刊

第一作者： Tang, Shanlong

作者： Tang, Shanlong;Li, Meijing;Zhong, Ruqing;Chen, Liang;Zhang, Hongfu;Sun, Yue;Liao, Yuanyuan;Wu, Xiaofeng

作者机构：

关键词： growing pigs; heat stress; immune organs; immunophenotyping; lymphocytes

期刊名称：JOURNAL OF ANIMAL SCIENCE （ 影响因子：3.338； 五年影响因子：3.243 ）

ISSN： 0021-8812

年卷期： 2022 年 100 卷 11 期

页码：

收录情况： SCI

摘要： This study illustrates that HS affects the lymphocyte immunophenotyping in pig spleen and thymus, providing novel information of the negative effects of chronic HS on functions of immune systems and its further molecular mechanism. This study aimed to investigate the effects of chronic heat stress on the immunophenotyping of lymphocytes in immune organs of growing pigs. A single-factor randomized block design was used, and 15 healthy growing large white barrows (5 litters, 3 pigs/litter) with similar body weight (40.8 kg) were assigned into 3 groups (5 pigs in each group). Groups were: control group (Con, in 23 degrees C environmental control chamber, fed ad libitum), heat stress group (HS, in 33 degrees C environmental control chamber, fed ad libitum), and pair-fed group (PF, in 23 degrees C environmental control chamber, fed diets according to the feed intake of HS group). After a 7-d adaption, the experiment lasted for 21 d. The results showed as follows: (1) activated T cells in the thymus of HS pigs were higher than those in PF pigs (P < 0.05). Monocytes and dendritic cells in the thymus of HS pigs were significantly higher than that in Con and PF pigs (P < 0.05), while the proportions of these 2 lymphocytes in the thymus of Con pigs did not differ from PF pigs (P > 0.05). Compared with Con pigs, the proportion of CD4(+) (P < 0.05) and CD8(+) T cells (P < 0.10) in the thymus was increased in HS pigs, while the proportion of CD4(+) and CD8(+) T cells in PF pigs did not differ from Con pigs (P > 0.05). (2) Compared with Con pigs, significantly decreased T cells, increased B cells and monocytes were found in the spleen of pigs exposed to heat stress (P < 0.05); the proportions of these 3 types of lymphocytes were not significantly different between Con and PF pigs (P > 0.05). The proportions of CD4(+) T cells and Treg cells in the spleen of pigs exposed to heat stress tended to be lower than those in the Con pigs (P < 0.10). (3) The proportion of lymphocytes in the tonsils of pigs exposed to heat stress did not differ from Con pigs (P > 0.05); compared with PF pigs, the proportion of Treg cells was significantly decreased in HS pigs (P < 0.05). In conclusion, chronic heat stress stimulates the development and maturation of T cells in the pig thymus toward CD4(+) and CD8(+) T cells and increases the proportion of monocytes and dendritic cells; under the condition of chronic heat stress, the immune response process in the spleen of pigs is enhanced, but chronic heat stress impairs the survival of CD4(+) T cells in the spleen. Lay Summary Chronic heat stress (HS) has become a common hazard to livestock and poultry as global warming intensifies and breeding densities increase, which undoubtedly causes enormous economic losses to animal husbandry annually. Furthermore, it could also negatively impact the immune function of poultry and vaccines, resulting in various animal diseases. Until now, very few studies have focused on how HS affects the immune system of growing pigs, especially the immunophenotyping of lymphocytes in their immune organs (thymus, spleen and tonsils). In this study, the spleen and thymus are more severely affected by chronic HS than tonsils in growing pigs. Chronic HS stimulates the development and maturation of CD4(+) and CD8(+) T lymphocytes in the thymus. Under chronic HS, the immune response process in the spleen is enhanced, that is, the proportion of monocytes and B lymphocytes supporting immune responses increased, while the proportion of Treg cells decreased; yet long-term HS damaged the survival of CD4(+) T lymphocytes in spleen.

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