Date of Completion

8-30-2017

Embargo Period

2-26-2018

Keywords

inflammation, maternal nutrition, pregnancy, sheep

Major Advisor

Sarah Reed

Associate Advisor

Steven Zinn

Associate Advisor

Kristen Govoni

Associate Advisor

Tania Huedo-Medina

Associate Advisor

Rachael Gately

Field of Study

Animal Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Breeding and management of pregnant females are essential components of livestock production. Improper gestational management creates maternal stressors which negatively affect prenatal and postnatal offspring development. We hypothesized that 1) using transabdominal ultrasound, pregnancy diagnosis would be accurate during early gestation in ewes and measure fetal growth patterns during mid-gestation, and 2) inflammation may be a mechanism contributing to suboptimal offspring performance when maternal nutrition is poor during gestation. To investigate, 99 ewes were scanned three times per wk between d26 and d40 of gestation. The sensitivity and specificity of pregnancy diagnoses were >90% from d33 onward, coinciding with visualization of fetal and placental development. This demonstrated that transabdominal ultrasound can be accurately integrated during early gestation for proactive flock management. Ewes determined to be pregnant (n=82) were randomly assigned to diets of 100% (CON), 60% (RES) or 140% (OVER) of NRC from d30 through parturition. Ultrasounds continued weekly between d45 and d90 to monitor growth of the fetal heart width (HW), umbilical diam., (UMB) and rib width (RW). At d45 and d90, ewes (n=20 or 21) were euthanized and fetuses were obtained for comparative gross measurements. As gestation advanced, measurement of the HW and UMB increased (PP<0.12). Interactions of maternal diet and litter size with gestation were observed for the RW; however, the effects were inconsistent and explained by Bland-Altman analysis that demonstrated measurement bias on ultrasound. At d45 ultrasound measurement underestimated RW by 7.7% but overestimated RW by 23.8% at d90. To determine how gestational diet affected the inflammatory status of dams (n=5 to 7 per diet) and offspring (n=6 per diet), RT-PCR arrays were utilized. RES and OVER promoted differing maternal systemic pro-inflammatory gene expression, with RES linked to increased NEFA concentrations. At birth, offspring systemic C-C motif chemokine ligand 8 increased in RES and OVER, and hepatic tumor necrosis factor increased in RES. Pro-inflammatory cytokines induced by maternal diet may antagonize offspring growth and performance. Future research may address anti-inflammatory interventions which can be implemented according to gestational information gained via ultrasound.

Available for download on Monday, February 26, 2018

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