ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2019, Vol. 50 ›› Issue (6): 1219-1229.doi: 10.11843/j.issn.0366-6964.2019.06.012

• ANIMAL NUTRITION AND FEEDS • Previous Articles     Next Articles

Effects of Acute Heat Stress on Blood Biochemistry Indices and Expression of HSP70 Family Genes in Blood Lymphocytes in Goats

PENG Xiaokun, ZHAO Tian, HUANG Xiaoyu, ZHANG Yu, XING Xiaonan, ZHANG Enping*   

  1. College of Animal Science and Technology, Northwest A & F University, Yangling 712100, China
  • Received:2018-09-03 Online:2019-06-23 Published:2019-06-23

Abstract: This experiment was conducted to explore the effects of acute heat stress on antioxidant capacity, immune function and expression of HSP70 family genes in blood lymphocytes in goats. Five (12±0.5)-month-old healthy female goats (F1 of Boer goat×Guanzhong dairy goat) were selected and raised separately in cage in an environment controlled chamber (temperature:20℃, relative humidity:60%), adaptation period lasted for 5 days. At the 6th day, five goats were treated with acute heat stress at 38℃ for 12 h. Blood samples were collected before heat stress (0 h, 20℃) and after 2, 4, 8 and 12 h of heat stress. Serum antioxidant indexes (total antioxidant capacity, superoxide dismutase, glutathione peroxidase activity and malondialdehyde content), serum immune indexes (serum immunoglobulin and cytokine contents) and the expression of HSP70 family member genes (HSPA1A, HSPA6 and HSPA8) in blood lymphocytes were measured by colorimetric method, ELISA and RT-PCR, respectively. The results showed as follows:1) Heat stress time had significant effects on serum antioxidant indexes. Compared with 0 h before heat stress, serum T-AOC (P<0.05), SOD (P<0.05) and GSH-Px (P<0.01) activities decreased significantly after 8 h of heat stress, and MDA content increased significantly after 4 h of heat stress (P<0.05). 2) Heat stress time had also significant influence on serum immune indexes. The contents of serum TNF-α and IL-2 increased significantly after 4 h of heat stress (P<0.05), while the contents of IL-1β and IFN-γ increased significantly after 8 h of heat stress (P<0.05). The contents of IgG (P<0.01), IgM (P<0.01) and IgA (P<0.05) decreased significantly after 4 h of heat stress, while the content of IL-4 decreased significantly after 12 h of heat stress(P<0.01). 3) Heat stress time significantly increased the expression levels of HSP70 family genes (HSPA1A, HSPA6 and HSPA8) in blood lymphocytes. The mRNA expression of HSPA1A rose firstly, then declined, and then it reached the peak at 4 h after heat stress. In addition, the mRNA expression of HSPA1A was significantly higher at 2, 4, 8 and 12 h after heat stress than at 0 h (P<0.01). The mRNA expression of HSPA6 increased significantly at 2 h after heat stress (P<0.01), and returned to pre-stress level after 4 h (P>0.05). The mRNA expression of HSPA8 was significantly higher at 4 (P<0.05), 8 (P<0.01), 12 h (P<0.01) after heat stress than that at 0 h. In this experiment, acute heat stress at 38℃ could inhibit the immune and antioxidant functions and increased the mRNA expression of HSPA1A, HSPA6 and HSPA8 genes in blood lymphocytes. HSPA1A was more sensitive to temperature and time of heat stress, and could be used as a molecular marker of early heat stress in goats.

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