Sidhu Pritam Kaur, Mahajan Vishal, Verma Sunil, Gupta Mohinder Partap
Department of Animal Disease Research Centre, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India.
Toxicol Int. 2014 May;21(2):186-90. doi: 10.4103/0971-6580.139806.
Plant associated nitrate/nitrite poisoning in buffalo, cattle, goat and sheep had been reported from various parts of the world. Horses and pigs are considered less susceptible to nitrate poisoning. In this study epidemiology of rare outbreak of nitrate poisoning in combination with classical swine fever in a small pig farm was investigated for development of strategies to control and prevent such incidents in future.
Concurrent infection of nitrate toxicity and classical swine fever were recorded in district Nawanshahar, Punjab. Eight pigs suddenly fell sick and died 2 days after feeding barseem + oats and marriage waste food. Twelve pigs were sick exhibiting symptoms of anorexia, fever (104-105(o)F), depression, constipation followed by diarrhea, respiratory difficulty, tremors and staggering gait with recumbency in four completely off-feed pigs. Blotchy discolorations of the skin of extremities (ears and snout) were observed in three pigs.
Hematological examination revealed marked leucopenia. Postmortem examination revealed dark brown colored blood evident on opening the carcass and presence of barseem, oats in stomach and intestines. Lymph nodes were swollen and hemorrhagic. Serosal surface of spleen show various infarcts and button ulcers were recorded in cecum and colon, pathognomic lesion of classical swine fever. Nitrate toxicity was confirmed on the basis of quantitative determination of nitrate in the biological material of sick and dead animals. Fodder samples were (barseem + oats) positive for diphenylamine blue (DPB) test, Nitrate concentration in offended barseem and oats were found to be 2612 ppm and 3344 ppm as nitrate nitrogen (No3-N), respectively. Excessive amount of nitrate in stomach contents (924-1365 ppm), liver (22-48 ppm) and kidney (17-22 ppm) of dead animals (n = 8) confirmed that death of pigs was due to toxicity induced by nitrate/nitrite.
The green fodder should be used cautiously in pigs and screening of fodder with DPB test prior offering to animals is strongly recommended to contain the nitrate/nitrite toxicity risk.
世界各地均有报道水牛、牛、山羊和绵羊发生与植物相关的硝酸盐/亚硝酸盐中毒事件。马和猪被认为对硝酸盐中毒的易感性较低。在本研究中，对一个小型养猪场罕见的硝酸盐中毒与经典猪瘟并发疫情进行了流行病学调查，以制定未来控制和预防此类事件的策略。
在旁遮普邦瑙万沙哈尔地区记录到硝酸盐中毒与经典猪瘟的并发感染情况。8头猪在喂食苜蓿 + 燕麦和婚宴剩菜2天后突然生病死亡。12头猪患病，表现出厌食、发热（104 - 105华氏度）、抑郁、便秘继而腹泻、呼吸困难、震颤以及蹒跚步态，4头完全拒食的猪出现躺卧症状。3头猪的四肢（耳朵和口鼻部）皮肤出现斑点状变色。
血液学检查显示明显的白细胞减少。尸检发现打开尸体时血液呈深褐色，胃和肠道中有苜蓿和燕麦。淋巴结肿大且出血。脾脏浆膜表面有各种梗死灶，盲肠和结肠出现纽扣状溃疡，这是经典猪瘟的特征性病变。通过对患病和死亡动物生物材料中硝酸盐的定量测定，证实了硝酸盐中毒。饲料样本（苜蓿 + 燕麦）二苯胺蓝（DPB）试验呈阳性，受污染的苜蓿和燕麦中的硝酸盐浓度分别为2612 ppm和3344 ppm（以硝酸盐氮计，No3 - N）。死亡动物（n = 8）胃内容物（924 - 1365 ppm）、肝脏（22 - 48 ppm）和肾脏（17 - 22 ppm）中硝酸盐含量过高，证实猪的死亡是由硝酸盐/亚硝酸盐引起的中毒所致。
猪使用绿色饲料时应谨慎，强烈建议在将饲料投喂给动物之前用DPB试验对饲料进行筛查，以降低硝酸盐/亚硝酸盐中毒风险。
