Wanja Daniel W, Mbuthia Paul G, Waruiru Robert M, Mwadime Janet M, Bebora Lilly C, Nyaga Philip N, Ngowi Helena A
University of Nairobi, College of Agriculture and Veterinary Sciences, Department of Veterinary Pathology, Microbiology and Parasitology, P.O. Box 29053-00625, Kangemi, Nairobi, Kenya.
Sokoine University of Agriculture, College of Veterinary and Medical Sciences, P.O. Box 3000, Chuo Kikuu, Morogoro, Tanzania.
Vet Med Int. 2020 Mar 19;2020:6839354. doi: 10.1155/2020/6839354. eCollection 2020.
Fish mortality has an enormous impact on the aquaculture industry by reducing fish production and slowing industrial growth. A cross-sectional study was carried out in Kirinyaga County, Central Kenya, to evaluate potential risks of fish mortality and disease transmission and suitability of pond water for rearing fish. A semistructured questionnaire that focused on general information, management practices, and disease history was administered to 92 small-scale fish farmers. Parasitological examination of fish sampled from selected farms (farms that were reporting mortality at the time of sampling) was done by following the standard procedure. Water quality parameters for 33 ponds were evaluated (recorded on pond site) and (analysed at the laboratory) following the standard methods. The risks were assessed by adjusted odds ratio based on univariate regression analysis. Prevalent fish husbandry practices that were found to be associated with fish mortality and acquisition of pathogens in the study area were the use of raw livestock manure (0R = 1.500), high fish stocking density (0R = 1.168), and feeding fish on homemade rations (0R = 1.128). Parasitological investigation found infestation with spp., spp., spp., and leeches. Water temperature and pH were found fit for rearing fish. Of the 33 fishpond water samples tested, 1 (3%) and 6 (18%) exceeded the recommended limits of <100 mg/L and <0.2 mg/L of nitrate and nitrite, respectively. Of the 29 fishpond water tested, 15 (59%) exceeded the recommended limits of <100 mg/L of total ammonia. The findings show that the use of raw livestock manure, high fish stocking density, high nitrates and nitrites, and high ammonia levels in fishponds are potential risk factors for fish mortality and acquisition of infectious pathogens in a pond environment in a rural setup, in Central Kenya. There is a need to address the above factors in small-scale farming practices to minimize fish loss and also to prevent the occurrence and spread of infectious pathogens.
鱼类死亡通过降低鱼类产量和减缓产业增长，对水产养殖业产生巨大影响。在肯尼亚中部的基里尼亚加县开展了一项横断面研究，以评估鱼类死亡和疾病传播的潜在风险以及池塘水用于养鱼的适宜性。向92位小规模养鱼户发放了一份侧重于一般信息、管理做法和疾病史的半结构化问卷。从选定养殖场（在采样时报告有鱼类死亡的养殖场）采集的鱼进行寄生虫学检查时遵循标准程序。按照标准方法对33个池塘的水质参数进行了评估（在池塘现场记录）并（在实验室分析）。基于单变量回归分析，通过调整后的比值比评估风险。在研究区域发现，与鱼类死亡和病原体感染相关的常见养鱼做法包括使用生畜粪肥（比值比=1.500）、高鱼类放养密度（比值比=1.168）以及用自制饲料喂鱼（比值比=1.128）。寄生虫学调查发现有 属、 属、 属寄生虫和水蛭感染。发现水温及pH值适合养鱼。在检测的33个鱼塘水样中，分别有1个（3%）和6个（18%）超过了硝酸盐<100毫克/升和亚硝酸盐<0.2毫克/升的推荐限值。在检测的2个鱼塘水中，15个（59%）超过了总氨<100毫克/升的推荐限值。研究结果表明，在肯尼亚中部农村地区的池塘环境中，使用生畜粪肥、高鱼类放养密度、高硝酸盐和亚硝酸盐以及高氨水平是鱼类死亡和感染性病原体感染的潜在风险因素。有必要在小规模养殖实践中解决上述因素，以尽量减少鱼类损失，并防止感染性病原体的发生和传播。
