Abstract :
The effects of supplementation with clinoptilolite, a mineral from sedimentary deposits,
were evaluated in a controlled and randomized field study conducted on a sheep farm with
a known history of coccidiosis. Two groups of 6 pregnant ewes each, with three replicates
per group (3 experimental and 3 control groups) were included in the study. Sheep were
kept in pens and given free access to a basal diet or a clinoptilolite diet formulated by supplementation
of the basal diet with clinoptilolite at a level of 1.25% and feed intake was
determined on a daily basis. Clinoptilolite was fed to the experimental group for a mean of
72 days (30 ± 1.7 days before lambing through 42 days after lambing) and examination of
fecal samples was performed every seven days in ewes as well as on days 12, 14, 21, 28, 35,
and 42 in their lambs. The assessment of supplementation efficacy was based mainly on
total oocyst excretion of Eimeria oocysts in ewes and their offspring, and on morphology
of Eimeria oocysts. On day 42, efficacy reached a significant (P ≤ 0.05) reduction of 97% in
oocyst output in supplemented ewes in contrast with control animals. Lambs born from
supplemented ewes showed a reduction of 98% in oocyst output in a mean of 28 ± 2.14 days
after birth. Oocysts kept under laboratory sporulation conditions in 2% aqueous potassium
dichromate as standard for optimal sporulation. The proportion of sporulated oocysts was
determined microscopically every 12 h. Exposure to clinoptilolite in vitro or in vivo did not
affect significantly the sporulation of oocysts shed by naturally infected sheep. However,
72% and 38% of sporulated oocysts isolated from supplemented and non-supplemented
sheep, respectively, were deemed microscopically as damaged and seen to collapse when
incubated in the presence of clinoptilolite. Oocysts from control ewes remained morphologically
undamaged. These results suggest that clinoptilolite could reduce fecal shedding
of infective oocytes by ewes which would result in less environmental contamination and
lower the incidence of infection in suckling lambs under field conditions.
