Ž .
Ž .
Fig. 2. Mean LSmeansSEM frequency of phasic pressure fluctuations frequencyrminute of the isthmus Ž
. Ž
. before and after ovulation in the control —l—, ns 5 and fasted – –B– –, ns5 sows, expressed as
Ž .
percentage of the within-group level before ovulation y11 to 0, time 0 s ovulation . Values with different Ž
. letters between the groups differs significantly
p- 0.05 . Values with different numbers within the same Ž
. group differ significantly p- 0.05 .
25 to 36 h after ovulation and remained thereafter unchanged. In the F-group, mean pressure remained unchanged during the period from 1 to 12 h after ovulation. Mean
Ž .
pressure then decreased significantly P - 0.05 during the periods from 13 to 24 h and 25 to 36 h after ovulation. Thereafter, mean pressure remained unchanged.
Changes in percent of the mean frequency of phasic pressure fluctuations Ž
. frequencyrminute before and after ovulation in the control and fasted sows are
Ž presented in Fig. 2. Calculated as 100 of the 12 h interval before ovulation y11 to 0
. Ž
. h , the frequency of phasic pressure fluctuations in the F- was 100 4.0 46.6 1.8
Ž .
and in the C-group was 100 4.0 41.7 1.8 . The mean frequency of phasic
Ž .
Ž pressure fluctuations was significantly higher
P - 0.05 in the F-
81.7 4.0; .
Ž .
38.1 1.8 than in the C-group 68.6 4.0; 28.9 1.8 during the period from 13 to 24 h after ovulation.
4. Hormones
4.1. Progesterone LSmeans SEM , F-group n s 5, C-group n s 5 Fig. 3 shows the changes in plasma progesterone before and after ovulation in the
control and fasted sows. No significant differences in progesterone were seen between
Ž .
Ž .
Fig. 3. Plasma progesterone LSmeansSEM levels before and after ovulation in the control —l—, ns 5 Ž
. Ž
. and fasted – –B– –, ns5 sows time 0sovulation . Values with different letters within the same group
Ž . Ž
. differ significantly p- 0.05 . A, B, C, D and E relate to the F- while a, b, c, d and e relate to the C-group .
the two groups either before or after ovulation. However, in both groups, plasma Ž
. progesterone levels increased significantly
P - 0.05 from 2.2 0.3 and 1.5 0.3 Ž
. nmolrl during the initial period 11 to 0 h before ovulation to 3.7 and 2.8 nmolrl
during the period from 1 to 12 h after ovulation, in the control and fasted sows, respectively. Thereafter, plasma progesterone levels continued to rise significantly in
both groups.
4.1.1. Oestradiol-17b LSmeans SEM , F-group n s 5, C-group n s 4 Percent changes in plasma oestradiol-17b levels are presented in Fig. 4. There were
no significant differences in the plasma oestradiol-17b levels between the C- and the Ž
. F-groups. Calculated as 100 of the 12 h interval before ovulation 11 to 0 h , the
Ž .
F-group showed a significant decrease P - 0.05 in the plasma oestradiol-17b levels Ž
. Ž
. from 100 6.4
6.8 0.5 pmolrl during the initial period
11 to 0 h before
Ž .
ovulation to 71.3 6.4 4.7 0.5 pmolrl during the period from 1 to 12 h after ovulation. Thereafter, plasma oestradiol-17b levels fluctuated between 60.8 6.4
Ž .
Ž .
3.8 0.5 pmolrl and 65.2 6.6 3.9 0.5 pmolrl during the periods from 13 to 24 h and 25 to 36 h after ovulation. In the C-group, plasma oestradiol-17b levels
Ž .
Ž .
decreased significantly P - 0.05
from 100 7.1 5.6 0.6 pmolrl during the
Ž .
Ž .
initial period 11 to 0 h prior to ovulation to 75.4 7.1 4.1 0.6 pmolrl during the period from 13 to 24 h after ovulation.
Ž .
Ž Fig. 4. Plasma oestradiol-17b LSmeansSEM levels before and after ovulation in the control —l—,
. Ž
. Ž
ns 4 and fasted – –B– –, ns5 sows expressed as percentage of the respective level pre-ovulation y11 .
Ž .
to 0, time 0 s ovulation . Values with different letters within the same group differ significantly p- 0.05 .
4.1.2. Prostaglandin metabolite LSmeans SEM , F-group n s 5, C-group n s 5 Ž
Fig. 5 shows the changes in the plasma prostaglandin F metabolite 15-ketodihy-
2 A
. dro-PGF
in the F- and C-sows. In the F-group, prostaglandin F metabolite levels
2 A 2 A
Ž .
increased significantly P - 0.05 from 339.0 23.9 pmolrl during the initial period Ž
. 11 to 0 h before ovulation to 423.5 24.9 pmolrl during the period from 1 to 12 h
after ovulation. Prostaglandin F metabolite continued to rise reaching maximum
2 A
values of 644.8 25.5 pmolrl 25 to 36 h after ovulation. There were no changes in the levels of prostaglandin F
metabolite before or after ovulation in the C-group. There
2 A
Ž .
were no significant p 0.05 differences in the levels of prostaglandin F metabolite
2 A
Ž .
between the F- and C-group sows during the initial period 11 to 0 h before ovulation . Ž
. However, prostaglandin F
metabolite levels were significantly P - 0.001 higher in
2 A
the F- than the C-group sows during all periods after ovulation. 4.1.3. Insulin, triglycerides and free fatty acids Means SD , F-group n s 5, C-group
n s 5 Ž
. Ž
. Serum insulin levels were significantly P s 0.05 lower 8.3 6.6 mUrml in the F-
Ž .
than in the C-group 12.6 4.5 mUrml while free fatty acids were significantly Ž
. Ž
. Ž
p - 0.01 higher 0.54 0.32 mmolrl in the F- than in the C-group 0.19 0.17
Ž .
Fig. 5. Plasma prostaglandin F metabolite LSmeansSEM levels before and after ovulation in the control
2 a
Ž .
Ž .
Ž .
—l—, ns 5 and fasted – –B– –, ns5 sows time 0sovulation . Values with different letters
Ž .
between the two groups differ significantly p- 0.05 . Values with different numbers within the same group Ž
. differ significantly p- 0.05 .
. mmolrl . There were no significant differences in the serum levels of triglycerides
Ž .
Ž .
between the F- 0.59 0.16 mmolrl and the C-group 0.73 0.24 mmolrl .
5. Discussion
