Abstract:

In order to find out the infection intensity and type of Sarcocystis ovis in Xining of Qinghai Province, different parts of muscle tissues of slaughtered sheep were randomly collected from markets, supermarkets and vendors in districts and counties under the jurisdiction of Xining. Microscopic examination and staining section observation were conducted for morphological identification. Genomic DNA extracted from myocardial and diaphragm samples of sheep with high worm content was taken for PCR amplification and sequencing analysis of mitochondrial cytochrome C oxidase subunit 1 (Cox1) gene. The results showed that in Xining, the infection rate of Sarcocystis ovis was 82.5%, and the average infection intensity was 7.67. In terms of parasitic sites, the highest infection rate was found in diaphragm (75%), followed by that in myocardium (67.5%), tongue (57.5%), while no infection was found in esophageal muscle. The muscle tissue at the edge of the worm was loose, and the cyst wall of the worm was divided into two layers. The structure of the primary and secondary cyst wall was flat, without protrusion and wrinkle. The 905bp target fragment was amplified by PCR and the sequence was aligned in GenBank. The homology between the target fragment and the published sequence of Sarcocystis tenella was 98%. So it was identified as Sarcocystis tenella. In conclusion, this research preliminarily clarified that the main infection of sheep in Xining of Qinghai Province is Sarcocystis tenella, and the infection rate in Xining is higher than the average level in China. We suggest that the laboratory detection, transportation and slaughter inspection and quarantine of Sarcocystis ovis in Xining of Qinghai Province should be strengthened, to ensure the sanitary quality of mutton products in market and the health and food safety of the public.

Key words: sheep, infection intensity, cytochrome C oxidase subunit 1, Sarcocystis tenella