硫化氢暴露不同时长对断奶仔猪生长性能、血液指标及组织病理学的影响

本试验旨在研究15 mg·m^-3硫化氢暴露不同时长,对断奶仔猪生长性能、血液生理生化指标以及主要呼吸、循环、代谢和免疫器官健康的影响。试验选取35日龄健康断奶仔猪12头,平均体重（11.25±0.69）kg,随机分为2组,每组6个重复,公母各半,分别饲喂在2个密闭的环控舱内,对照组硫化氢浓度为0 mg·m^-3,试验组硫化氢浓度为15 mg·m^-3,试验期28 d。测定其生长性能、血液生理生化、脏器指数等指标并观察组织病理学变化。结果显示：1）生长性能测定结果：试验组较对照组的平均日采食量（ADFI）、平均日增重（ADG）和料重比（F/G）无显著性差异（P>0.05）。2）血常规测定结果：硫化氢暴露2 d,试验组中平均红细胞体积（MCV）、血小板压积（PCT）、平均血小板体积（MPV）、血小板分布宽度（PDW）显著升高（P<0.05）,平均血红蛋白浓度（MCHC）显著降低（P<0.05）;暴露14 d,试验组中淋巴细胞百分比（LYM%）、平均血红蛋白含量（MCH）显著升高（P<0.05）,红细胞总数（RBC）显著降低（P<0.05）;暴露28 d,粒细胞百分比（GRA%）、血红蛋白（HGB）、MCH、PDW显著升高（P<0.05）,血小板总数（PLT）、PCT显著降低（P<0.05）。3）肝、心及肾功能相关生化指标测定结果：硫化氢暴露2 d,试验组中总蛋白（TP）、谷丙转氨酶（ALT）、总胆红素（TBIL）和肌酸激酶（CK）显著升高（P<0.05）;暴露14和28 d,与肝、心以及肾功能相关的生化指标均无显著性差异（P>0.05）。4）免疫相关指标检测结果：硫化氢暴露2 d,试验组中免疫球蛋白A（IgA）显著升高（P<0.05）;暴露14 d,试验组中各项指标无显著性差异（P>0.05）;暴露28 d,试验组中IgA、免疫球蛋白M（IgM）和C反应蛋白（CRP）显著升高（P<0.05）。5）脏器指数及组织病理学观察结果：试验结束时,肺、肝、心、肾、脾以及胸腺的脏器指数均无显著性变化（P>0.05）,组织病理学观察结果仅在肺中发现轻微炎症性损伤,其余器官未见明显病理性损伤。以上结果表明,断奶仔猪暴露于浓度为15 mg·m^-3硫化氢中,短时间内可能引起免疫应答以及一定的肝功能和心功能损伤,随着时间的积累,各器官发生代偿修复,机体适应能力增强,但长时间暴露会造成肺炎症性损伤,不利于断奶仔猪生长和健康。

Effects of Hydrogen Sulfide Exposure for Different Duration on Growth Performance,Blood Indexes and Histopathology in Weaned Piglets

This experiment was conducted to study the effects of 15 mg·m^-3 H₂S exposure for different duration on the growth performance, blood physiological and biochemical indicators and the health of the main respiratory, circulatory, metabolic and immune organs in weaned piglets. Twelve healthy 35-day-old weaned piglets with an average body weight of (11.25±0.69) kg were randomly divided into 2 groups with 6 replicates per group and half males and half females in each group. The piglets were fed in 2 sealed environment controlled chambers, respectively. The concentration of hydrogen sulfide in the control group was 0 mg·m^-3, the concentration of hydrogen sulfide in the experimental group was 15 mg·m^-3. The experiment lasted for 28 days. The growth performance, blood physiology and biochemistry indicators, organ indexes and histopathological observation were measured. The results showed as follows:1) The results of growth performance:Compared with the control group, there were no significant changes in ADFI, ADG and F/G in experimental group (P>0.05). 2) The results of blood routine indexes:In the experimental group, MCV, PCT, MPV and PDW were significantly increased (P<0.05) and MCHC were significantly decreased (P<0.05) after 2 days of H₂S exposure; LYM% and MCH were significantly increased (P<0.05) and RBC were significantly decreased (P<0.05) after 14 days of H₂S exposure. GRA%, HGB, MCH and PDW were significantly increased (P<0.05) after 28 days of H₂S exposure, while PLT and PCT were significantly decreased (P<0.05). 3) The results of the serum biochemical indexes related to liver, heart and kidney functions:Serum TP, ALT, TBIL and CK in experimental group were significantly increased (P<0.05) after 2 days of H₂S exposure. There were no significant differences in biochemical indexes related to liver, heart and kidney functions after 14 and 28 days of H₂S exposure (P>0.05), respectively. 4) The results of serum immune-related indicators:In the experimental group, IgA was significantly increased (P<0.05) after 2 days of H₂S exposure, and there were no significant differences in all indicators after 14 days of H₂S exposure (P>0.05); IgA, IgM and CRP were significantly increased (P<0.05) within 28 days of H₂S exposure. 5) The results of organ indexes and histopathology:There were no significant changes in the organ indexes of lung, liver, heart, kidney, spleen and thymus (P>0.05) within 28 days of H₂S exposure. Histopathological observation revealed that slight inflammatory damage was found only in the lung, while no pathological damage was observed in the other organs. The above results showed that for the weaned piglets under different exposure times at the concentration of 15 mg·m^-3 H₂S, a short period of exposure may cause immune response as well as liver and heart injury. Then with the time accumulation of exposure, each organ proceeded compensatory repair by itself and enhanced the adaptability. But long time exposure induced slight inflammatory injury in lung, ultimately not conducive to the growth and health of weaned piglets.