| Summary: | 博士 === 國立中興大學 === 獸醫學系 === 89 === 文摘要(Summary)
From July 1997 to March 1999, coccidial infection in Galliforme birds in a total of 19 zoos and pheasant farms in Taiwan were investigated by fecal examination. A total of 395 fecal samples from 41 species of birds were collected. From flotation method examinations, 96 fecal samples (24.3%) were found to contain coccidial oocysts. After sporulation, the oocysts from the 96 fecal samples examined showed 75 samples belonging to the genus Eimeria (78.1%), 24 samples to the genus Isospora (25.0%), 8 samples to the genus Gousseffia (8.3%) and 5 samples to the genus Pythonella (5.2%). This is the first report of the genera Gousseffia and Pythonella in Taiwan.
The non-sporulated oocysts of Eimeria colchici, a cecal coccidium of pheasants, were obtained by artificial inoculation; these oocysts were divided equally and treated with following 13 kinds of chemicals for one hour. After the treatment, the oocysts were washed by distilled water and centrifuged for 4 times to eliminate the remaining chemicals. They were then incubated at 28℃ constantly for 36 hours to calculate the sporulation rates of each test group and compared them to the rates of control group. The results indicated that treating with ammonia solution showed the best inhibition effect on oocysts sporulation (92.85%), the second was phenol (38.22%) and the third was hyamine (18.73%). After the sporulation, the E. colchici oocysts, which were obtained by the same way as the above, were treated with the same 13 kinds of chemicals for one hour, washed and centrifuged for 5 times and artificial inoculated to 14 days old pheasants, the orally inoculation dose was 120,000 oocysts. Compared to the control group, the mortality of Ammonia solution treated group was lowest, being 16.67% (3/18), and in other groups (including positive control) all the inoculated pheasants died(18/18).
Unsporulated oocysts of E. colchici, the cecal coccidium of Phasianus colchicus, were collected from the faeces after artificial inoculation. These and other groups of unsporulated oocysts from the cecal mucosa were immersed in ammonia solutions in different concentration (0.75%, 0.25%, 0.125% and 0.025%) for 1 hour, then washed with distilled water and centrifuged twice for 4 times to eliminate the remained ammonia. After incubating at a constant temperature of 28℃ for 36 hours, the sporulation ratios between ammonia-treated groups and negative control had been calculated. The results indicated that the stronger the concentration of ammonia solution, the better the inhibition effect to the sporulation of oocyst. Unsporulated oocysts collected from faeces were immersed in 4 different concentration of ammonia solutions, and the sporulation-inhibition ratio from high concentration to low one are 99.82%, 37.14%, 28.55% and 0% in order. The unsporulated oocysts collected from cecal mucosa were treated as the above, and the results are 99.68%, 96.42%, 57.81% and 26.05% respectively. It shows that if the concentration of ammonia solution is below 0.25%, the unsporulated oocysts which had been excreted from animals have more resistance to it than the ones which stay in the cecal mucosa still; besides, the ammonia solution in concentration lower than 0.025% will not have the capacity to kill the oocysts which have been excreted from animals.
Non-sporulated oocysts of E. colchici, when exposed to ozone showed lower sporulation ratio than the untreated one. Lower sporulation ratio was observed, with longer ozone exposure time. Among the 14-day-old Phasianus colchicus that were each orally inoculated with 120,000 sporulated oocysts which have been exposed to ozone for 15, 30 and 60 minutes, lower mortality were observed for those inoculated with oocysts treated with ozone for longer, period of time and the oocysts in feces per gram was also less than the untreated control group. Thus ozone treatment of oocyst had been shown to inhibit the growth and infectivity of E. colchici.
Low-dose immunization of pheasants with live E. colchici oocysts was observed to be effective against massive challenge infection. Fourteen-day-old pheasants, in groups of 28, were orally inoculated with about 100, 250, 500, 1,000 and 2,000 sporulated oocysts. These birds were then challenged homologously with about 120,000 sporulated oocysts 18 days after the immunization. During the 12 days observation period after the challenge infection, over 92.86% of the immunized pheasants were still alive, but only 10.71% of the non-immunized control birds survived the challenge infection. Moreover, the number of oocysts produced after challenge infection of the immunized gro
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