Ontogeny of metabolic effects on embryonic development in lactating and weaned primiparous sows
M. D. Vinsky A , F. Paradis A , W. T. Dixon A , M. K. Dyck A and G. R. Foxcroft A BA Swine Reproduction-Development Program, Swine Research & Technology Centre, University of Alberta, Edmonton, Alberta, Canada.
B Corresponding author. Email: george.foxcroft@ualberta.ca
Reproduction, Fertility and Development 19(5) 603-611 https://doi.org/10.1071/RD06116
Submitted: 8 September 2006 Accepted: 16 April 2007 Published: 31 May 2007
Abstract
Using an established experimental paradigm, feed restriction during the last week of lactation in primiparous sows reduces embryonic growth and development and produces female-specific embryonic mortality by Day 30 of gestation. Because this gender-specific loss of embryos at Day 30 was associated with changes in the variation of markers of epigenetic imprinting, the present study sought to establish the ontogeny of such epigenetic affects. Leucocyte DNA of restrict-fed sows exhibited decreased global methylation during the last week of lactation and during the return to oestrus (P < 0.05), but no associated changes in plasma folate and vitamin B12. Furthermore, no changes in methylation of blastocyst DNA, embryonic sex ratios or development were evident at Day 6 of gestation that would characterise the underlying defects that reduced female embryo survival by Day 30. However, regardless of treatment, embryo recovery rates and synchrony in embryonic development were associated with the stage of development of the recovered embryos (r = 0.68; P < 0.001). The subset of sows classified as bearing litters with superior embryonic development had lower net energy balance over lactation (P < 0.01) and higher ovulation rates (P < 0.005) compared with sows classified as having poorer embryonic development. Collectively, these data suggest that a subset of litters within restrict-fed sows will be most sensitive to the latent epigenetic mechanisms that ultimately trigger gender-specific loss of embryos by Day 30 of gestation, but that these selective mechanisms are not evident by Day 6 of gestation.
Acknowledgements
The authors acknowledge the staff of the University of Alberta Swine Research & Technology Center for their dedication in maintenance and care of the experimental animals. The authors are also grateful to Dr Peter Blenis for help with the statistical analysis, Shirley Shostak for guidance with the radioimmunoassay and Dr Gord Murdoch for advice on the polymerase chain reaction. Funding for this work was received from Natural Sciences and Engineering Research Council of Canada, Alberta Agricultural Research Institute, Alberta Pork and Hypor Inc. and through appointment of Dr George Foxcroft to a Canada Research Chair in Swine Reproductive Physiology.
Almeida, F. R. , Mao, J. , Novak, S. , Cosgrove, J. R. , and Foxcroft, G. R. (2001). Effects of different patterns of feed restriction and insulin treatment during the luteal phase on reproductive, metabolic, and endocrine parameters in cyclic gilts. J. Anim. Sci. 79, 200–212.
| PubMed |
Foxcroft, G. R. (1997). Mechanisms mediating nutritional effects on embryonic survival in pigs. J. Reprod. Fertil. Suppl. 52, 47–61.
| PubMed |
Park, I. Y. , Sohn, B. H. , Choo, J. H. , Joe, C. O. , Seong, J. K. , Lee, Y. I. , and Chung, J. H. (2005). Deregulation of DNA methyltransferases and loss of parental methylation at the insulin-like growth factor II (Igf2)/H19 loci in p53 knockout mice prior to tumor development. J. Cell. Biochem. 94, 585–596.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Pope, W. F. , Xie, S. , Broermann, D. M. , and Nephew, K. P. (1990). Causes and consequences of early embryonic diversity in pigs. J. Reprod. Fertil. Suppl. 40, 251–260.
| PubMed |
Silk, J. B. (1983). Local resource competition and facultative adjustment of sex-ratios in relation to competitive abilities. Am. Nat. 121, 56–66.
| Crossref | GoogleScholarGoogle Scholar |
Vanyushin, B. F. , Tkacheva, S. G. , and Belozersky, A. N. (1970). Rare bases in animal DNA. Nature 225, 948–949.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Vinsky, M. D. , Novak, S. , Dixon, W. T. , Dyck, M. K. , and Foxcroft, G. R. (2006). Nutritional restriction in lactating primiparous sows selectively affects female embryo survival and overall litter development. Reprod. Fertil. Dev. 18, 347–355.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Vinsky, M. D. , Murdoch, G. K. , Dixon, W. T. , Dyck, M. K. , and Foxcroft, G. R. (2007). Altered epigenetic variance in surviving litters from nutritionally restricted lactating primiparous sows. Reprod. Fertil. Dev. 19, 430–435.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Whittemore, C. T. , and Yang, H. (1989). Physical and chemical composition of the body of breeding sows with differing body subcutaneous fat depth at parturition, differing nutrition during lactation and differing litter size. Anim. Prod. 48, 203–212.
Yi, P. , Melnyk, S. , Pogribna, M. , Pogribny, I. P. , Hine, R. J. , and James, S. J. (2000). Increase in plasma homocysteine associated with parallel increases in plasma S-adenosylhomocysteine and lymphocyte DNA hypomethylation. J. Biol. Chem. 275, 29 318–29 323.
| Crossref | GoogleScholarGoogle Scholar |
Yoshida, M. , Ishigaki, K. , Nagai, T. , Chikyu, M. , and Pursel, V. G. (1993). Glutathione concentration during maturation and after fertilization in pig oocytes: relevance to the ability of oocytes to form male pronucleus. Biol. Reprod. 49, 89–94.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
Zak, L. J. , Cosgrove, J. R. , Aherne, F. X. , and Foxcroft, G. R. (1997). Pattern of feed intake and associated metabolic and endocrine changes differentially affect postweaning fertility in primiparous lactating sows. J. Anim. Sci. 75, 208–216.
| PubMed |
