Effects of selenium supply and dietary restriction on maternal and fetal body weight, visceral organ mass, cellularity estimates, and jejunal vascularity in pregnant ewe lambs

¹ Center for Nutrition and Pregnancy, Animal and Range Sciences Department, North Dakota State University, Fargo
² Agricultural Research Service, United States Department of Agriculture, Dubois, Idaho, United States; , United States

^* To whom correspondence should be addressed. E-mail: joel.caton{at}ndsu.edu.

	Abstract

To examine effects of nutrient restriction and dietary Se on maternal and fetal visceral tissues, 36 pregnant Targhee-cross ewe lambs were allotted randomly to 1 of 4 treatments in a 2 x 2 factorial arrangement. Treatments were plane of nutrition (control; 100% of requirements vs. restricted; RES, 60% of controls) and dietary Se (adequate Se; ASe, 6 µg/kg BW vs. high Se; HSe, 80 µg/kg BW) from Se enriched yeast. Selenium treatments were initiated 21 d before breeding and restriction began on d 64 of gestation. Diets contained 16% CP and 2.12 Mcal/kg ME (DM basis) and differing amounts were fed to control and RES groups. On d 135 ± 5 (mean ± range) of gestation, ewes were slaughtered and visceral tissues harvested. There was a nutrition x Se interaction (P = 0.02) for maternal jejunal RNA:DNA; no other interactions were detected for maternal measurements. Maternal BW, stomach complex, small intestine, large intestine, liver, and kidney mass were less (P 0.01) in RES than control ewes. Lung mass (g/kg empty BW) was greater (P = 0.09) in RES than control ewes and for HSe compared with ASe ewes. Maternal jejunal protein content and protein:DNA were less (P 0.002) in RES than control ewes. Maternal jejunal DNA and RNA concentrations and total proliferating jejunal cells were not affected (P 0.11) by treatment. Total jejunal and mucosal vascularity (mL) were less (P 0.01) in RES than control ewes. Fetuses from RES ewes had less BW (P = 0.06), empty carcass weight (P = 0.06), crown to rump length (P = 0.03), liver (P = 0.01), pancreas (P = 0.07), perirenal fat (P = 0.02), small intestine (P = 0.007), and spleen weights (P = 0.03) compared with controls. Fetuses from HSe ewes had heavier (P 0.09) BW, empty carcass, heart, lung, spleen, total viscera, and large intestine weights compared with ASe ewes. Nutrient restriction resulted in less protein content (mg, P = 0.01) and protein:DNA (P = 0.06) in fetal jejunum. Fetal muscle DNA (nutrition by Se interaction; P = 0.04) concentration was greater (P < 0.05) in restricted ewes fed HSe compared with other treatments. Fetal muscle RNA concentration (P = 0.01) and heart RNA content (P = 0.04) were greater in HSe vs. ASe ewes. Data indicate that maternal dietary Se may alter fetal responses as noted by greater heart, lung, spleen, and BW.

Key Words: fetal, maternal, nutrient restriction, pregnancy, selenium