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This Article Full Text (PDF) All Versions of this Article: jas.2008-1043v1 87/1/222    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Caton, J. S. Articles by Wallace, J. M. Search for Related Content PubMed PubMed Citation Articles by Caton, J. S. Articles by Wallace, J. M.

Effects of maternal nutrition and stage of gestation on body weight, visceral organ mass, and indices of jejunal cellularity, proliferation, and vascularity in pregnant ewe lambs

J. S. Caton^*, J. J. Reed^*, R. P. Aitken, J. S. Milne, P. P. Borowicz^*, L. P. Reynolds^*, D. A. Redmer^* and J. M. Wallace

^* Center for Nutrition and Pregnancy, Dept. of Animal Science, North Dakota State University, Fargo Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, United Kingdom

Joel.Caton{at}ndsu.edu

Abstract

Peri-pubertal ewe lambs (44.3 ± 1.1 kg initial BW) were used in a 2 x 3 factorial design to test effects of plane of nutrition (diet) and stage of gestation on maternal visceral tissue mass, intestinal cellularity, crypt cell proliferation, and jejunal mucosal vascularity. Singleton pregnancies to a single sire were established by embryo transfer, and thereafter ewes were offered a control (Control) or high (High) level of a complete diet (2.84 Mcal/kg and 15.9% CP; DM basis) to promote slow or rapid maternal growth rates. After d 90 of gestation, feed intake of the Control group was adjusted weekly to maintain BCS and meet the increasing nutrient demands of the gravid uterus. Ewes were slaughtered at 50 (n = 6 Control, 5 High), 90 (n = 8 Control, 6 High), or 130 (n = 8 Control, 6 High) d of gestation. Ewes were eviscerated and mass of individual organs recorded. The jejunum was sampled and processed for subsequent analyses. Final ewe BW for Control ewes was similar at d 50 and 90 and increased (P = 0.10) from d 90 to 130 (46.0, 48.9, and 58.2 ± 1.6 kg, respectively), whereas final BW increased (P 0.01) throughout gestation in High ewes (58.3, 68.8, and 81.1 ± 1.6 kg, respectively). Relative jejunum mass (g/kg maternal BW) was greater (P = 0.003) in Control compared with High ewes and tended (P = 0.11) to decrease from d 50 to 130. There were diet x stage of gestation interactions (P 0.08) for ileum and small intestinal total and relative weights. Ileum mass (g/kg maternal BW) in Control ewes was less (P = 0.07) compared with High ewes at d 50, was equal (P = 0.19) to High ewes at d 90, and greater (P = 0.02) than High ewes at d 130. Small intestine mass (g/kg maternal BW) was similar between Control and High ewes at d 50 and 90, but Control ewes had greater (P = 0.01) mass at d 130. Jejunal RNA and protein concentrations were lower (P 0.07) and DNA unaffected (P = 0.43) in Control vs. High ewes. Stage of gestation did not affect jejunal RNA, DNA (mg/g), or protein concentrations. Jejunal cellular proliferation was not affected by diet or stage of gestation. In jejunal mucosal tissue, capillary number decreased whereas capillary surface density and area per capillary increased (P = 0.01) with advancing pregnancy (d 50 vs. d 130) but were independent of diet. Data indicate that intestinal mass as a proportion of maternal BW declines in over-nourished gestating ewe lambs. This response is more pronounced during late gestation and is likely explained by increasing maternal BW and adiposity rather than changing cellularity or cell proliferation.

Key Words: cellularity • intestine • nutrition • pregnancy • vascularity