仔猪肠道疾病.ppt

Enteric Diseases of Young Pigs仔猪肠道疾病 作者：Larry Firkins, DVM, MS, MBA College of Veterinary Medicine University of Illinois 美国伊利诺斯大兽医学院 Definition of Diarrhea下痢的定义 Excess water in feces relative to dry matter.粪中含水量过大 Normally, much of the fluid is absorbed in the small intestine before it exits the ileum 通常，大部分水都在进入回肠之间就在小肠中被吸收了 Colon serves to conserve water and electrolytes结肠只起吸收水和电解质的作用 Mechanisms of Diarrhea下痢的机理 Secretory Diarrhea分泌性下痢 Result of the effect of enterotoxins secreted by bacteria and some viruses细菌和其它病毒分泌的肠毒素造成的结果 Alteration in secretion of electrolytes, water, and bicarbonate: gradient pulls water into lumen电解质、水和碳酸氢钠的分泌发生改变：使水进入肠腔 Absorption continues: Chyle in lymphatics Mechanisms of Diarrhea下痢的机理 Malabsorptive Diarrhea吸收不良性下痢 Reduction in surface area of intestine肠粘膜表面积减少 Loss of absorptive capacity吸收能力减弱 Villous atrophy绒毛萎缩 Chyle absent in lymphatics淋巴乳糜缺乏 Undigested ingesta ferments未消化的食糜发酵 Mechanisms of Diarrhea下痢的机理 Effusive Diarrhea渗漏性下痢 Result of severe damage to mucosa粘膜严重受损的结果 Necrotoxins produced by bacteria细菌产生的坏死毒素 Leakage of serum proteins and water due to vascular damage血管受损导致血清蛋白质和水漏出 Loss of absorptive capacity吸收能力减弱 Arriving at a Diagnosis诊断 History病史 Age of onset发病年龄 Vaccination history免疫接种历史 Sudden death vs. protracted diarrhea猝死和长期下痢 Arriving at a Diagnosis诊断 Selection of specimens病料采集 Diarrhea of 24 hrs or less下痢开始后24小时以内 Untreated未经治疗 Avoid pigs which “died during the night”不要从夜间死亡的猪采集病料 Selecting Segments of Intestine肠段的选择 Histopathology组织病理学 Sections representative of all areas of intestines要选择能代表肠道所有区域的部分 Better to have many small pieces than one large piece最好要采集多个较短肠段，而不要只采集一个很长的肠段 Segments ~ 1 cm long, opened lengthwise根据纵向尺寸的不同，采集1厘米左右的肠段 Selecting Segments of Intestine肠段的选择 Fresh samples样本要新鲜 7 – 10 cm segments of ileum, jejunum7～10厘米回肠和空肠的肠段 Segment of spiral colon结肠螺旋襻的肠段 Causes of pig diarrheas仔猪肠炎原因 Nursing Weaning 断奶前 断奶后 E. coli 大肠杆菌 11% 49%