臺灣地區白肉種雞場之沙門氏菌汙染模式研究

Abstract

沙門氏菌是造成人類食因病的重要病因之一，經常藉由食入受汙染的禽肉與禽製品感染。本調查的目的是希望能找出並釐清臺灣白肉種雞場之汙染模式，以有助於政府對白肉種雞場進行的監測計畫與沙門氏菌控制計畫之研擬。本研究針對臺灣地區十四場白肉種雞場自其一日齡雛雞進雛起進行縱向性長期觀測，樣本總共2132個，包括一日齡雛雞(只有11場從一日齡雛雞開始監測)、沾有墊料和糞便的鞋套、飼料、水樣、中止蛋與孵化出之子代小雞，並依樣本種類不同共分成為1080個檢驗樣本，總分離率為8.3% (90/1080)；其中一日齡雛雞之分離率為24.6% (15/61)；沾有墊和料糞便的鞋套之分離率為13.1% (52/398)；飼料之分離率為5.5% (16/292)；水樣之分離率為0% (0/133)；中止蛋與孵化出之子代小雞之分離率為3.6% (7/196)。在這14場白肉種雞場中只有12場能從一日齡雛雞與鞋套樣本中分離到沙門氏菌，場陽性率為85.7%(12/14)，其中以S. Albany、S. Duesseldorf與S. Schwarzengrund等血清型最常被分離到，同時利用脈衝式電泳之分子分型以將分離株進行親緣性關係鑑定。從本次調查的結果發現在臺灣地區的白肉種雞場中，以一日齡雛雞是白肉種雞場內重要的沙門氏菌感染來源，而由飼料樣本分離到之沙門氏菌血清型與基因型來看，發現飼料雖然有被沙門氏菌汙染的情形出現，但造成白肉種雞場內持續傳播感染的機率卻不高。並且同一基因型的沙門氏菌在感染後可以持續於雞場內傳播，並可能經由垂直傳播模式傳給子代的商用白肉雞，因此在選購沙門氏菌清淨的小種雞是很重要的關鍵。另外在本次調查中亦發現白肉種雞場的種雞飼育隻數、飼育設備與白肉種雞場之沙門氏菌感染關係不大。

Salmonella is one of the important causes of human food disease, and people were often infected through ingestion of contaminated poultry and poultry products. The purpose of this study is to identify and clarify the pollution patterns of broiler breeder farms in Taiwan, and help the government carry out the monitor plan and develop the Salmonella control plan of broiler breeder farms. In this study, 14 broiler breeder farms in Taiwan were investigated by longitudinal observation since the first days of the 1-day-old chicken. The total numbers of samples were 2132, including 1-day-old chicken (there are only 11 farms sent samples of 1-day-old chichken), shoe covers stained with litter and feces, feed, water, suspended eggs and hatched chicken, and was divided into 1080 test samples according to the different types of samples. The total isolation rate was 8.3% (90/1080); the isolation rate of 1-day-old chicken was 24.6% (15/61); the isolation rate of shoe covers stained with litter and feces was 13.1% (52/398); the isolation rate of feed was 5.5% (16/292); the isolation rate of water was 0% (0/133); the isolation rate of suspended eggs and hatched chicken was 3.6% (7/196). In the 14 breeder farms, Salmonella were isolated from 12 farms, and the farm positive rate was 85.7%(12/14). In this study, S. Albany, S. Duesseldorf, and S. Schwarzengrund were the most frequently isolated serotypes and we used pulsed field gel electrophoresis to identify the genetic relationships of Salmonella isolates. These results showed that samples of 1-day-old chicken are important sources of Salmonella infection and though feed can be contaminated by Salmonella, the risk of Salmonella infection of chicken from feed is not very high. The Salmonella of the same genotype can persistently transmit in the broiler breeder farm, and may transmit to the child commercial broiler through vertical transmittion. Therefore, it is an important key to buy Salmonella free broiler breeder chicks. In this study we also found that the relationship of Salmonella infection between the numbers of broiler breeder and the raising facilities of broiler breeder farms is not close.