|Abstract or Summary
- Two lots of six White Leghorn male chickens were fed diets containing
7.3% linoleic acid and either .075% ethoxyquin (lot 1) or 32.4
mg/kg of added vitamin E (lot II) for 47 weeks both of which were
designated as positive controls. A third group (lot III) containing 30
males received the same level of linoleic acid but had no added
vitamin E or ethoxyquin until the 38th week when the lot was divided
into five sub-lots, equalized for fertility, based on the results of the
34th week. At this time the subdivided lots were supplemented with
.075 or .3% ethoxyquin (lots IV and V) and 32.4 or 162.0 mg/kg of
vitamin E (lots VI and VII) while one group was retained as the negative
control (lot III).
During the depletion period fertility in lot III, the negative control
group, decreased to 29.2% at 38 weeks. Fertility in the lots supplemented
throughout the trial with .075% ethoxyquin (lot I) and 32.4
mg/kg of vitamin E (lot II) was significantly greater than lot III beginning at 25 and 30 weeks, respectively, and throughout the remainder
of the depletion period. During the depletion period no
meaningful differences were observed between the two positive control
groups. At 47 weeks, fertility of the lot retained as the negative
control decreased to 4.8% while fertility in lots supplemented
with .075 or .3% ethoxyquin (lots IV and V) and 32.4 or 162.0 mg/kg
of vitamin E (lots VI and VII) increased to levels comparable to the
positive controls. At 47 weeks fertility in all supplemented lots was
significantly greater than the negative control.
Semen density from males in lot III decreased with each measurement
throughout the depletion period. Lot I had a significantly
higher density than the negative control beginning at 20 weeks and
throughout the remainder of the experiment, except during the 30th
week while lot II was significantly greater during the 34th and 38th
weeks of the depletion period and at 47 weeks. No significant differences
were present between the positive control lots throughout
the trial. At 47 weeks, density in all supplemented lots was significantly
greater than the negative control with the exception of lot IV.
The pattern of significant differences for concentration was
quite similar to that for semen density during the depletion period
except lot I was significantly greater than lot II at 12 weeks and lot
III at 30 weeks. With the exception of lot IV, semen concentration
in all supplemented lots was significantly higher than that of lot III
at the end of the trial. No meaningful differences were noted for hatchability of fertile
eggs, semen volume, sperm live-dead percent, feed consumption or
body weight throughout the trial.
From these findings one may conclude the following:
1. Male chickens fed diets high in linoleic acid maintained
their fertilizing capacity when supplemented with . 075% ethoxyquin
or 32.4 mg/kg of vitamin E when compared to the .3% and 162.0
mg/kg, respectively, reported by Arscott et al. (1965).
2. Sterility induced by linoleic acid and a deficiency of vitamin
E and ethoxyquin in male chickens was equally reversible by supplementation
with .075% ethoxyquin and 32.4 mg/kg of vitamin E as well
as .3% ethoxyquin and 162.0 mg/ kg of vitamin E. Thus, vitamin E
appears to act similarly to an antioxidant in reversing sterility of
male chickens fed diets high in linoleic acid.
3. The procedure for semen concentration outlined in this
thesis gave results similar to the procedure for semen density (Kosin
and Wheeler, 1956) in determining the percent of sperm per unit
volume of semen.