Carlson D B, Reed J J, Borowicz P P, Taylor J B, Reynolds L P, Neville T L, Redmer D A, Vonnahme K A, Caton J S
Center for Nutrition and Pregnancy, Department of Animal and Range Science, North Dakota State University, Fargo 58105, USA.
J Anim Sci. 2009 Feb;87(2):669-80. doi: 10.2527/jas.2007-0837. Epub 2008 Nov 7.
The objectives were to examine effects of dietary Se supplementation and nutrient restriction during defined periods of gestation on maternal adaptations to pregnancy in primigravid sheep. Sixty-four pregnant Western Whiteface ewe lambs were assigned to treatments in a 2 x 4 factorial design. Treatments were dietary Se [adequate Se (ASe; 3.05 microg/kg of BW) vs. high Se (HSe; 70.4 microg/kg of BW)] fed as Se-enriched yeast, and plane of nutrition [control (C; 100% of NRC requirements) vs. restricted (R; 60% of NRC requirements]. Selenium treatments were fed throughout gestation. Plane of nutrition treatments were applied during mid (d 50 to 90) and late gestation (d 90 to 130), which resulted in 4 distinct plane of nutrition treatments [treatment: CC (control from d 50 to 130), RC (restricted from d 50 to 90, and control d 90 to 130), CR (control from d 50 to 90, and restricted from d 90 to 130), and RR (restricted from d 50 to 130)]. All of the pregnant ewes were necropsied on d 132 +/- 0.9 of gestation (length of gestation approximately 145 d). Nutrient restriction treatments decreased ewe ADG and G:F, as a result, RC and CR ewes had similar BW and maternal BW (MBW) at necropsy, whereas RR ewes were lighter than RC and CR ewes. From d 90 to 130, the HSe-CC ewes had greater ADG (Se x nutrition; P = 0.05) than did ASe-CC ewes, whereas ADG and G:F (Se x nutrition; P = 0.08) were less for HSe-RR ewes compared with ASe-RR ewes. The CR and RR treatments decreased total gravid uterus weight (P = 0.01) as well as fetal weight (P = 0.02) compared with RC and CC. High Se decreased total (g; P = 0.09) and relative heart mass (g/kg of MBW; P = 0.10), but increased total and relative mass of liver (P < or = 0.05) and perirenal fat (P < or = 0.06) compared with ASe. Total stomach complex mass was decreased (P < 0.01) by all the nutrient restriction treatments, but was reduced to a greater extent in CR and RR compared with RC. Total small intestine mass was similar between RC and CC ewes, but was markedly reduced (P < 0.01) in CR and RR ewes. The mass of the stomach complex and the small and large intestine relative to MBW was greater (P = 0.01) for RC than for CR ewes. Increased Se decreased jejunal DNA concentration (P = 0.07), total jejunal cell number (P = 0.03), and total proliferating jejunal cell number (P = 0.05) compared with ASe. These data indicate that increased dietary Se affected whole-body and organ growth of pregnant ewes, but the results differed depending on the plane of nutrition. In addition, the timing and duration of nutrient restriction relative to stage of pregnancy affected visceral organ mass in a markedly different fashion.
本研究旨在探讨在初产妊娠绵羊的特定妊娠期内，日粮添加硒及营养限制对母体妊娠适应性的影响。64只怀孕的西部白面母羊羔羊按2×4析因设计进行处理。处理因素为日粮硒水平[充足硒（ASe；3.05微克/千克体重）与高硒（HSe；70.4微克/千克体重）]，以富硒酵母形式饲喂，以及营养水平[对照（C；100%的NRC需求）与限制（R；60%的NRC需求）]。整个妊娠期都给予硒处理。营养水平处理在妊娠中期（第50至90天）和晚期（第90至130天）进行，从而产生4种不同的营养水平处理[处理组：CC（第50至130天为对照）、RC（第50至90天限制，第90至130天对照）、CR（第50至90天对照，第90至130天限制）和RR（第50至130天限制）]。所有怀孕母羊在妊娠第132±0.9天（妊娠期约145天）进行剖检。营养限制处理降低了母羊的平均日增重（ADG）和料重比（G:F），结果，RC和CR组母羊在剖检时体重和母体体重（MBW）相似，而RR组母羊比RC和CR组母羊轻。从第90至130天，HSe - CC组母羊的ADG（硒×营养；P = 0.05）高于ASe - CC组母羊，而HSe - RR组母羊的ADG和G:F（硒×营养；P = 0.08）低于ASe - RR组母羊。与RC和CC组相比，CR和RR处理降低了妊娠子宫总重量（P = 0.01）以及胎儿体重（P = 0.02）。与ASe相比，高硒降低了心脏总重量（克；P = 0.09）和相对心脏重量（克/千克MBW；P = 0.10），但增加了肝脏总重量和相对重量（P≤0.05）以及肾周脂肪总重量和相对重量（P≤0.06）。所有营养限制处理均降低了胃复合体总重量（P < 0.01），但CR和RR组比RC组降低幅度更大。RC和CC组母羊的小肠总重量相似，但CR和RR组母羊的小肠总重量显著降低（P < 0.01）。RC组母羊的胃复合体以及小肠和大肠相对于MBW的重量比CR组母羊更大（P = 0.01）。与ASe相比，硒增加降低了空肠DNA浓度（P = 0.07）、空肠总细胞数（P = 0.03）和空肠增殖细胞总数（P = 0.05）。这些数据表明，日粮硒增加影响了怀孕母羊的全身和器官生长，但结果因营养水平而异。此外，相对于妊娠阶段的营养限制时间和持续时间以明显不同方式影响内脏器官重量。
