Abstract: The studies on isoenzyme of esterase (EST) and dehydrogenase (LDH) in adults and larvae of Chinese and American Trichinella spiralis (T.s) by PAGE and UVP gel documentation analysis system were reported. The results showed that there were 2 bands of EST isoenzyme in adults and larvae of Chinese heilongjian T.s , respectively. There was only one band of LDH in Chinese T.s larvae. In EST analysis 3 and 2 enzymatic bands were found in adults and larvae of American T.s , respectively. No LDH isoenzyme band of were observed in adults of Chinese and American T.s . Otherwise one band was found both in Chinese larvae and American larvae, the relative mobility was also different. The results indicated that there was genetic difference in different geographical T.s strains. In addition, there was great difference in isoenzyme patterns of different developmental stages of T.s .

Key words: different developmental stages of T.s, isoenzyme of esterase(EST), isoenzyme of dehydrogenase (LDH)