热应激对泌乳母猪泌乳量、血液生化指标和免疫指标的影响

Effects of Heat Stress on Milk Yield,Blood Physiological,Biochemical and Immunological Indices of Lactating Sows

本研究旨在探讨热应激对泌乳母猪泌乳量、血液生化指标和免疫指标的影响。泌乳母猪的舒适温度区为16～22℃,因此分别在高温季节(日平均温度28.41℃)和适温季节(日平均温度20.78℃)各对20头长白泌乳母猪(初产母猪6头,经产母猪14头)开展相应的热应激和非热应激试验,检测并分析泌乳母猪在2种不同环境温度下的泌乳量、血液生化指标和免疫指标变化。结果表明:热应激极显著降低了混合胎次所有母猪泌乳期的泌乳量(P<0.01),其中热应激显著降低了初产母猪泌乳第21～24、25～28天的日均泌乳量(P<0.05),并极显著降低了经产母猪泌乳第5～8、9～12、17～20、21～24、25～28天的日均泌乳量(P<0.01);热应激还造成总蛋白含量、谷丙转氨酶活性显著降低(P<0.05),总胆固醇含量极显著降低,而尿素氮含量和乳酸脱氢酶活性极显著增加(P<0.01);热应激对泌乳母猪的免疫性能造成严重影响,导致IgM、补体3、γ干扰素含量显著增加及CD8活性显著增强(P<0.05),IgG和白细胞介素-2含量极显著增加(P<0.01)。综上,持续热应激会导致泌乳母猪泌乳量减少,血液生化指标和免疫指标发生显著改变,从而对泌乳母猪的健康产生不利影响。

The aim of this study was to explore the effects of heat stress on milk yield,blood biochemical and immunological indices of lactating sows.Since 16~22℃is the thermal comfort zone for lactating sows,heat stress experiment and no heat-stress experiment were carried out on 20 Landrace lactating sows respectively in high temperature season(average daily temperature 28.41℃)and mild temperature season(average daily temperature 20.78℃).Then,the milk yield,blood biochemical and immunological parameters were measured and carried out statistical analysis.The results showed that heat stress reduced milk yield of all mixed parities lactating sows during lactation significantly(P<0.01),in which average daily milk yield(ADMY)at lactation 21~24 d and 25~28 d of primiparous sows were decreased(P<0.05),furthermore,ADMY at lactation 5~8 d,9~12d,17~20 d,21~24 d and 25~28 d of multiparous sows were decreased remarkably(P<0.01).For blood biochemical parameters,total protein(TP)content and glutamic-pyruvic transaminase(GPT)activity under heat stress were lower than those under non-heat stress(P<0.05),and total cholesterol(TCH)concentration under heat stress were lower than that under non-heat stress significantly(P<0.01),however,heat stress increased blood urea nitrogen(BUN)concentration,lactate dehydrogenase(LDH)activity remarkably(P<0.01).Finally,heat stress also affected lactating sows’immune function significantly,resulting in an increase in CD8 activity and IgM,complement 3(C3)and interferon-γ(IFN-γ)contents(P<0.05),and increasing the IgG and interleukin-2(IL-2)contents significantly(P<0.01).In conclusion,continuously heat stress had significant effects on milk yield,blood biochemical indices and immune performance,which could cause negative effects on lactating sows’health.