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Effect of a polychlorinated biphenyl mixture on swine reproduction and tissue residues
THERIOGENOLOGY
weeks prepartum. A C17,201yase activity was found, converting 17a progesterone into 170(,2Oalprogesterone, and androstenedione to estrone. It seems that placental exposure to either endogenous or exogenous glucocorticosteroids result in the induction of C17.201yase activities, and a subsequent rise in estrogen synthesis. W. Jtlchle PORCINE Oyck,
Effects of a cold environment and growth rate G. W.: on reproductive efficiency in gilts. Can. 3. Anim. 1974. Sci., %:207-292, Research Station, Agriculture Canada, Brandon, Manitoba.
Well documented information on environmental influences on nutritional requirements for growth and reproduction is sparce. In this study, 96 Lacombe gilts and El boars were assigned for a 42-day breeding season, and half of them kept in a heated piggery (lo-15OC) or in outside lots with a wooden cabin for shelter (mean maximum - 12oC, mean minimum -22OC). Food was provided for either minimum growth (O.OSkg/day) or moderate growth (0.36 kg/day). While gilts housed in the piggery were fed 1.5 and 3.0 kg/day, gilts housed outside had their feed consumption increased by a maximum of 1 kg/day to maintain similar growth rates. No effects of the cold environment ware seen on ovulation rate, fetal survival, fetal weight, uterine weight, and ovarian weight as measured at 60 days of gestation. The mean weight of corpora lutea was greater for gilts housed outside (498 vs. 459 g). Moderate growth rate was combined with a greater ovulation rate (13.4 vs. 12.3, p < 0.05), lower fetal survival (65.6 vs. 77.7 %, p C O.Ol), heavier fetuses (112.6 vs. 98.0 g, p c O.Ol), heavier uteri (1,556 vs. 1,391 g, p < 0.05), heavier ovaries (15.4 vs. 13.1 , p < O.Ol), and heavier corpora lutea (500 vs. 448 mg, p L 0.01 3' compared with minimum growth rates. Pregnancy rate was similar for the two groups (piggery, 77.1 '$; outside lots 72.9 %). Pregnancy rate was greater for gilts with moderate growth rate W. JBchle (85.4 VS. 64.6 $, p < 0.05). '-!nnscn,L. G., c. s. Cycrly, A. L. Iletco!.f& R. F. Bevill: iffact of a ;,olychlorinated biphenyi mixture on swine reproduction an!{ tissue residues. An. 3. Vet. Rcs., ;G ( lj.7.. li175. Gl;L,'Af Veterinary medicine, University of Illinois, Urbana, IL GltSOl, USA. Folychlorinatcd biphenyls(PC9) ore persistent chemicals wilich arc of low ncute but of much higher, even sublethal Since chronic exposure to small chrcnic to:;icLty to :ianmols. concontrstionc is hard to csccpc, concern is Crowing about T_‘Ci: iirfccts on re;lroduction and accumulation Ln tissues in ? '1il;i or;i:~~l fccrlin~ cf
MAY
spccic. 7
In
this
study,
the
long-tern
effect
of
PC3-mixture at a dose level of 20 ppm was test-
1975 VOL. 3 NO. 5
203
THERIOGENOLOGY
cd in length
third litter sows which At before being bred.
had
been
fed
at
least
one
cycle
each placenta was exfarrowing, Piglets were uoaned at 35 days -mined for mummified fetuses. slaughtered for pock-~artum, and all. sous and some piglets Trented sous farrawod 6.4 -idctsrnination. t i 7 c I ICI rcciduc 11.4 + 1.14 in controls (p c 0.05) vcrcuc L:.?.‘: 1 ivi? piglets PCR had no effect on Locta2nd lh,~rl norc nunrnificd TotusecT In the sous, PC0 tion c;nrl pi.zlct ncrtnl.ity before LJeaning. and erosion of the stonach, of the liver caused liy,1c rtrophy Glood and atrophy of spleen and thyroid glnnds. 2nd ciir,i1t !.r.veir;, with tircuz in sous 2nd piglets
the
exception
of
fat,
LJOT~ below
0.5
ppm
with ctrong varictions bctaecn individuals 2.5 ppn uere found in sows and 1.8 ppm and tissues. In fat, Individual differences in reproductive performance !n rviclets. related to exposure and tissue resiciur I.evclo L!crc directly effects and the lowest concentrations tirlc, i. e. the least U. Jtichle FCB exposure times. l,ero seen wth the shortest Webel,
S. K. & P. 3. Oziuk: Effect of stage of uterine space on prenatal survival in the Sci., 38(5):960-963, 1974. Univerxty of Illinois at Urbana-Champaign, inois 61801, USA.
gestation pig. J. Urbana,
and Anim. Ill-
Since it became known that in the sow only 60 to 65 % of the ovulated eggs are represented by live fetuses at term, causes for embryonic or fetal losses have been studied but are still not well understood. In this study, the possible role of utsrine space was examined in 25 gilts at three stages of gestation: Day 25-30, Day 31-40, and Day 41 to term. Uterine space was varied so that either twice normal, half-normal, or the normal amount of uterine space was available per embryo; this was done by unilateral oviduct ligation before or after superovulation; or removal of one ovary and the ipsilateral horn, which causes compensitory hypertrophy of the contralateral ovary but not of the remaining horn; or superovulation only. When the uterus was unchanged but the number of embryos entering the uterus was reduced, the proportion of embryos surviving at any stage of gestation was not different from normal. Decreasing the uterine space to half did not affect survival to Day 30, but the proporation of embryos surviving after Day 30 was reduced. These results strongly indicate that uterine space is not associated with the embryonic mortality observed before Day 30, but that it may be a factor in fetal death after Day 30, but only when large numbers of fetuses are present or when uterine space is restricted. A search for the causes of early embryonic losses might therefore be directed toward other areas like the possibility at fertilization errors or genetic aberrations. W. JHchle
204
MAY 1975 VOL. 3 NO. 5
weeks prepartum. A C17,201yase activity was found, converting 17a progesterone into 170(,2Oalprogesterone, and androstenedione to estrone. It seems that placental exposure to either endogenous or exogenous glucocorticosteroids result in the induction of C17.201yase activities, and a subsequent rise in estrogen synthesis. W. Jtlchle PORCINE Oyck,
Effects of a cold environment and growth rate G. W.: on reproductive efficiency in gilts. Can. 3. Anim. 1974. Sci., %:207-292, Research Station, Agriculture Canada, Brandon, Manitoba.
Well documented information on environmental influences on nutritional requirements for growth and reproduction is sparce. In this study, 96 Lacombe gilts and El boars were assigned for a 42-day breeding season, and half of them kept in a heated piggery (lo-15OC) or in outside lots with a wooden cabin for shelter (mean maximum - 12oC, mean minimum -22OC). Food was provided for either minimum growth (O.OSkg/day) or moderate growth (0.36 kg/day). While gilts housed in the piggery were fed 1.5 and 3.0 kg/day, gilts housed outside had their feed consumption increased by a maximum of 1 kg/day to maintain similar growth rates. No effects of the cold environment ware seen on ovulation rate, fetal survival, fetal weight, uterine weight, and ovarian weight as measured at 60 days of gestation. The mean weight of corpora lutea was greater for gilts housed outside (498 vs. 459 g). Moderate growth rate was combined with a greater ovulation rate (13.4 vs. 12.3, p < 0.05), lower fetal survival (65.6 vs. 77.7 %, p C O.Ol), heavier fetuses (112.6 vs. 98.0 g, p c O.Ol), heavier uteri (1,556 vs. 1,391 g, p < 0.05), heavier ovaries (15.4 vs. 13.1 , p < O.Ol), and heavier corpora lutea (500 vs. 448 mg, p L 0.01 3' compared with minimum growth rates. Pregnancy rate was similar for the two groups (piggery, 77.1 '$; outside lots 72.9 %). Pregnancy rate was greater for gilts with moderate growth rate W. JBchle (85.4 VS. 64.6 $, p < 0.05). '-!nnscn,L. G., c. s. Cycrly, A. L. Iletco!.f& R. F. Bevill: iffact of a ;,olychlorinated biphenyi mixture on swine reproduction an!{ tissue residues. An. 3. Vet. Rcs., ;G ( lj.7.. li175. Gl;L,'Af Veterinary medicine, University of Illinois, Urbana, IL GltSOl, USA. Folychlorinatcd biphenyls(PC9) ore persistent chemicals wilich arc of low ncute but of much higher, even sublethal Since chronic exposure to small chrcnic to:;icLty to :ianmols. concontrstionc is hard to csccpc, concern is Crowing about T_‘Ci: iirfccts on re;lroduction and accumulation Ln tissues in ? '1il;i or;i:~~l fccrlin~ cf
MAY
spccic. 7
In
this
study,
the
long-tern
effect
of
PC3-mixture at a dose level of 20 ppm was test-
1975 VOL. 3 NO. 5
203
THERIOGENOLOGY
cd in length
third litter sows which At before being bred.
had
been
fed
at
least
one
cycle
each placenta was exfarrowing, Piglets were uoaned at 35 days -mined for mummified fetuses. slaughtered for pock-~artum, and all. sous and some piglets Trented sous farrawod 6.4 -idctsrnination. t i 7 c I ICI rcciduc 11.4 + 1.14 in controls (p c 0.05) vcrcuc L:.?.‘: 1 ivi? piglets PCR had no effect on Locta2nd lh,~rl norc nunrnificd TotusecT In the sous, PC0 tion c;nrl pi.zlct ncrtnl.ity before LJeaning. and erosion of the stonach, of the liver caused liy,1c rtrophy Glood and atrophy of spleen and thyroid glnnds. 2nd ciir,i1t !.r.veir;, with tircuz in sous 2nd piglets
the
exception
of
fat,
LJOT~ below
0.5
ppm
with ctrong varictions bctaecn individuals 2.5 ppn uere found in sows and 1.8 ppm and tissues. In fat, Individual differences in reproductive performance !n rviclets. related to exposure and tissue resiciur I.evclo L!crc directly effects and the lowest concentrations tirlc, i. e. the least U. Jtichle FCB exposure times. l,ero seen wth the shortest Webel,
S. K. & P. 3. Oziuk: Effect of stage of uterine space on prenatal survival in the Sci., 38(5):960-963, 1974. Univerxty of Illinois at Urbana-Champaign, inois 61801, USA.
gestation pig. J. Urbana,
and Anim. Ill-
Since it became known that in the sow only 60 to 65 % of the ovulated eggs are represented by live fetuses at term, causes for embryonic or fetal losses have been studied but are still not well understood. In this study, the possible role of utsrine space was examined in 25 gilts at three stages of gestation: Day 25-30, Day 31-40, and Day 41 to term. Uterine space was varied so that either twice normal, half-normal, or the normal amount of uterine space was available per embryo; this was done by unilateral oviduct ligation before or after superovulation; or removal of one ovary and the ipsilateral horn, which causes compensitory hypertrophy of the contralateral ovary but not of the remaining horn; or superovulation only. When the uterus was unchanged but the number of embryos entering the uterus was reduced, the proportion of embryos surviving at any stage of gestation was not different from normal. Decreasing the uterine space to half did not affect survival to Day 30, but the proporation of embryos surviving after Day 30 was reduced. These results strongly indicate that uterine space is not associated with the embryonic mortality observed before Day 30, but that it may be a factor in fetal death after Day 30, but only when large numbers of fetuses are present or when uterine space is restricted. A search for the causes of early embryonic losses might therefore be directed toward other areas like the possibility at fertilization errors or genetic aberrations. W. JHchle
204
MAY 1975 VOL. 3 NO. 5