Impacts of maternal nutritional plane on umbilical artery hemodynamics, fetal and placentome growth in sheep

Abstract The present study aimed to examine the impact of maternal nutritional plane on umbilical hemodynamics. Ewes (n = 15) were assigned to 1 of 3 dietary treatments [control (CON; 100% of NRC requirements), restricted (RES; 60% of CON) or overfed (OVR; 140% of CON)] beginning on day 40 of gestation. Umbilical artery hemodynamics, fetal growth and placentome growth were measured on days 40, 45, 52, 80, 94 and 108 of gestation by Doppler ultrasonography. The percentage change in umbilical artery pulsatility and resistance indices remained steady through day 80 of gestation, and then decreased (P < 0.03) by day 108 of gestation. Moreover, plane of nutrition affected (P < 0.03) the percentage change in pulsatility index from day 40, with RES ewes having a greater (P < 0.03) change compared to CON (16.7 ± 7.5 vs. -15.6 ± 7.5%), with OVR being intermediate (3.2 ± 7.5%). Fetal biparietal and abdominal diameters increased (P < 0.01) throughout gestation, and fetal heart rate decreased (P < 0.01) from day 52 to 108 of gestation. Placentome diameter increased (P < 0.01) through day 80 of gestation, was similar (P > 0.05) on days 80 and 94 of gestation, and then decreased (P < 0.01) by day 108 of gestation. Maternal plane of nutrition can impact umbilical resistance indices, and ultimately may impact blood flow to the fetus

Epigenetics and developmental programming of welfare and production traits in farm animals

The concept that postnatal health and development can be influenced by events that occur in utero originated from epidemiological studies in humans supported by numerous mechanistic (including epigenetic) studies in a variety of model species. Referred to as the ‘developmental origins of health and disease’ or ‘DOHaD’ hypothesis, the primary focus of large-animal studies until quite recently had been biomedical. Attention has since turned towards traits of commercial importance in farm animals. Herein we review the evidence that prenatal risk factors, including suboptimal parental nutrition, gestational stress, exposure to environmental chemicals and advanced breeding technologies, can determine traits such as postnatal growth, feed efficiency, milk yield, carcass composition, animal welfare and reproductive potential. We consider the role of epigenetic and cytoplasmic mechanisms of inheritance, and discuss implications for livestock production and future research endeavours. We conclude that although the concept is proven for several traits, issues relating to effect size, and hence commercial importance, remain. Studies have also invariably been conducted under controlled experimental conditions, frequently assessing single risk factors, thereby limiting their translational value for livestock production. We propose concerted international research efforts that consider multiple, concurrent stressors to better represent effects of contemporary animal production systems

Nutrition During Gestation and Fetal Programming

Historically, considerable efforts have been made to understand how nutrition impacts health and productivity during the postnatal period. While maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition impacts the health and productivity of the offspring. Indeed, the prenatal growth trajectory is sensitive to the direct and indirect effects of maternal dietary intake from the earliest stages of embryonic life when the nutrient requirements for conceptus growth are negligible (Robinson et al., 1977). Not only is neonatal health compromised, but the subsequent health may be “programmed” as offspring from undernourished dams have been shown to exhibit poor growth and productivity and also to develop significant diseases later in life (Barker et al., 1993; Godfrey and Barker, 2000). Fetal, or developmental programming, defined as the concept that a maternal stimulus or insult at a critical period in fetal development has long term impacts on the offspring, was originally coined by Dr. David Barker, at Southampton University in England (Barker et al., 1993; Godfrey and Barker, 2000). Barker and his colleagues studied birth records in the United Kingdom and Europe, and related different maternal stresses to infant weight and physical characteristics at birth and to subsequent health status in later life. Of interest was that they determined that maternal undernutrition in the first half of gestation, followed by adequate nutrition from mid-gestation to term, resulted in infants of normal birth weight, which were proportionally longer and thinner than normal. This early fetal undernutrition resulted in an increased incidence of health problems experienced by these individuals as adults, including obesity, diabetes, and cardiovascular disease. In livestock production settings, undernutrition can often occur during gestation, particularly during the first two trimesters. This results from either low feed reserves and(or) management practices that result in cows losing weight during late fall and early winter (Sletmoen-Olsen et al., 2000a,b). However, current data indicate that health and growth of offspring born from undernourished mothers are diminished (Godfrey and Barker, 2000; Vonnahme et al., 2003). This theory of developmental programming has been experimentally challenged and verified using several animal models. While variations in the duration and severity of maternal undernutrition do not always result in a reduced birth weight, physiologic alterations such as glucose intolerance, skewed growth patterns and even alterations in carcass characteristics have been reported. Therefore, birth weight in and of itself may not be the best predictor for calf survival and productivity. The objective of this paper is to review the literature on bovine fetal and placental development and how maternal nutrition impacts fetal, neonatal and postnatal health and performance of the offspring. While this work will concentrate on beef cattle, examples from other species will be added when appropriate

Effects of maternal nutrition on conceptus growth and offspring performance: Implications for beef cattle production

Developmental programming is the concept that a maternal stimulus or insult at a critical period in fetal development has long-term effects on the offspring. Historically, considerable effort has been made to understand how nutrition influences health and productivity during the postnatal period. Whereas maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition affects the health and productivity of the offspring. Conceptus growth is sensitive to direct and indirect effects of maternal dietary intake. Even from the earliest stages of embryonic life, when nutrient requirements for conceptus growth are negligible, alterations in tissue composition can occur, influencing future growth of the compromised organ system. Not only is neonatal health compromised, but subsequent health may also be programmed because offspring from undernourished dams have exhibited poor growth and productivity and have developed significant diseases later in life. Although the literature is now evolving, with increasing evidence of how maternal nutrient restriction impairs several prenatal physiological variables, few studies have evaluated postnatal growth and development in livestock species, and fewer have evaluated it in beef cattle. In addition, very few studies have evaluated restriction of specific components of the diet during pregnancy (such as protein) on offspring growth and performance. This review focuses on how maternal nutrition affects conceptus growth and postnatal responses in beef cattle

Effects of maternal nutrient restriction followed by realimentation during midgestation on uterine blood flow in beef cows

The objective was to examine the effect of maternal nutrient restriction followed by realimentation during midgestation on uterine blood flow (BF). On Day 30 of pregnancy, lactating, multiparous Simmental beef cows were assigned randomly to treatments: control (CON; 100% National Research Council; n = 6) and nutrient restriction (RES; 60% of CON; n = 4) from Day 30 to 140 (period 1), and thereafter, realimented to CON until Day 198 of gestation (period 2). Uterine BF, pulsatility index (PI), and resistance index (RI) were obtained from both the ipsilateral and contralateral uterine arteries via Doppler ultrasonography. Generalized least square analysis was performed. Ipsilateral uterine BF in both groups increased quadratically (P \u3c 0.01) during period 1 and linearly (P \u3c 0.01) during period 2. There was a treatment (P = 0.05) effect during period 2; where RES cows had greater ipsilateral BF versus CON. Ipsilateral uterine PI and RI decreased linearly (P ≤ 0.01) during period 1 across treatments. Contralateral uterine BF in CON cows tended (P \u3c 0.09) to be greater versus RES in both periods. Contralateral PI in both groups increased linearly (P ≤ 0.01) during period 1. Contralateral uterine RI was increased (P ≤ 0.05) in RES cows versus CON in both periods. There was no interaction or treatment effect (P ≥ 0.24) for total BF during either period. Nutrient restriction does not alter total uterine BF, but it may increase vascular resistance. However, up on realimentation, local conceptus-derived vasoactive factors appear to influence ipsilateral uterine BF

Effects of Maternal Nutritional Plane and Selenium Supply on Cellularity Estimates of Neonatal Lamb Jejunal Mucosa, Heart, and Skeletal Muscle

Objectives were to investigate the effects of maternal nutrition and Se supply during gestation on lamb jejunal mucosa, heart, and skeletal muscle RNA, DNA, and protein. Rambouillet ewe lambs (n = 84) were allotted to a 2 x 3 factorial design including dietary factors of Se [adequate Se (ASe; 11.5 μg/kg BW) or high Se (HSe; 77.0 μg/kg BW)] and nutritional plane [60% (RES), 100% (CON), or 140% (HIGH)]. At breeding Se treatments were initiated followed by nutritional treatments on d 40 of gestation. At birth, lambs (n = 13, 14, 14, 12, 13, and 15 for ASe-RES, ASe-CON, ASe-HIGH, HSe-RES, HSe-CON, and HSe-HIGH, respectively) were removed from ewes before nursing, placed in a common pen, and group fed until necropsy at 20.6 ± 0.9 d of age. Maternal nutritional plane affected (P ≤ 0.07) offspring jejunal mucosal scrape concentration (mg/g) and total content (mg) of DNA where RES was least, HIGH greatest, and CON intermediate. Plane of nutrition also affected (P = 0.07) right ventricle DNA content where RES (189.8 ± 11.8 mg) was least, HIGH (208.2 ± 11.2 mg) intermediate, and CON (227.7 ± 11.3 mg) greatest. Maternal Se supplementation decreased (P = 0.08) left ventricle protein:DNA in offspring. For lamb right ventricle, RNA concentration was greatest (P = 0.05) for ASe-RES and least for HSe-RES with all other treatments intermediate. However when lamb right ventricle RNA was expressed as total content, HSe-RES was least (P = 0.02), ASe-HIGH intermediate, and all other treatments were greater. When RNA:DNA was calculated in right ventricle, ASe-RES and HSe-HIGH were greatest (P = 0.02), ASe-CON intermediate, and ASe-HIGH, HSe- RES, and HSe-CON least. Skeletal muscle RNA concentration and RNA:DNA were least (P \u3c 0.05) for ASe-HIGH, intermediate for HSe-RES and HSe-CON, and greatest for ASe-RES, ASe-CON, and HSe-HIGH. These data indicate cellularity estimates have tissue specific responses to maternal nutritional plane and Se supply

US Federal Travel Restrictions for Persons with Higher-Risk Exposures to Communicable Diseases of Public Health Concern

Published guidance recommends controlled movement for persons with higher-risk exposures (HREs) to communicable diseases of public health concern; US federal public health travel restrictions (PHTRs) might be implemented to enforce these measures. We describe persons eligible for and placed on PHTRs because of HREs during 2014–2016. There were 160 persons placed on PHTRs: 142 (89%) involved exposure to Ebola virus, 16 (10%) to Lassa fever virus, and 2 (1%) to Middle East respiratory syndrome coronavirus. Most (90%) HREs were related to an epidemic. No persons attempted to travel; all persons had PHTRs lifted after completion of a maximum disease-specific incubation period or a revised exposure risk classification. PHTR enforced controlled movement and removed risk for disease transmission among travelers who had contacts who refused to comply with public health recommendations. PHTRs are mechanisms to mitigate spread of communicable diseases and might be critical in enhancing health security during epidemics

Diversity and distribution of Tardigrada in Arctic cryoconite holes

Despite the fact that glaciers and ice sheets have been monitored for more than a century, knowledge on the glacial biota remains poor. Cryoconite holes are water-filled reservoirs on a glacier's surface and one of the most extreme ecosystems for micro-invertebrates. Tardigrada, also known as water bears, are a common inhabitant of cryoconite holes. In this paper we present novel data on the morphology, diversity, distribution and role in food web of tardigrades on Arctic glaciers. From 33 sampled cryoconite holes of 6 glaciers on Spitsbergen, in 25 tardigrades were found and identified. Five taxa of Tardigrada (Eutardigrada) were found in the samples, they are: Hypsibius dujardini, Hypsibius sp. A, Isohypsibius sp. A., Pilatobius recamieri, and one species of Ramazzottiidae. H. dujardini and P. recamieri were previously known from tundra in the Svalbard archipelago. Despite the number of studies on Arctic tundra ecosystems, Hypsibius sp. A, one species of Ramazzottiidae and Isohypsibius sp. A are known only from cryoconite holes. Tardigrade found in this study do not falsify the hypothesis that glaciers and ice sheets are a viable biome (characteristic for biome organisms assemblages -tardigrades). Diagnosis of Hypsibius sp. A, Isohypsibius sp. A, and species of Ramazzottiidae with discussion on the status of taxa, is provided. To check what analytes are associated with the presence of tardigrades in High Arctic glacier chemical analyses were carried out on samples taken from the Buchan Glacier. pH values and the chemical composition of anions and cations from cryoconite holes water from the Buchan Glacier are also presented. The current study on the Spitsbergen glaciers clearly indicates that tardigrade species richness in cryoconite holes is lower than tardigrade species richness in Arctic tundra ecosystems, but consists of unique cryoconite hole species. As cryoconite tardigrades may feed on bacteria as well as algae, they are primary consumers and grazers-secondary consumers of the decomposer food chain in this extreme ecosystem

Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes

The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/ kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed individually from d 40, and lambs were removed at parturition. Colostrum was milked from all ewes at 3 h postpartum, and one-half of the ewes (n = 42) were transitioned to a common diet meeting lactation requirements and mechanically milked for 20 d. Colostrum yield was greater (P = 0.02) for HSe ewes than ASe, whereas CON had greater (P \u3c 0.05) colostrum yield than RES and HIH. Colostrum Se (%) was greater (P \u3c 0.01) for HSe than ASe. Colostrum from ewes fed HSe had less (P = 0.03) butterfat (%), but greater (P ≤ 0.05) total butterfat, solids-notfat, lactose, protein, milk urea N, and Se than ASe. Colostrum from HIH ewes had greater (P ≤ 0.02) solids- not-fat (%) than RES, whereas RES had greater (P ≤ 0.04) butterfat (%) than CON and HIH. Colostrum from ewes fed the CON diet had greater (P = 0.01) total butterfat than HIH. Total solids-not-fat, lactose, and protein were greater (P \u3c 0.05) in colostrum from CON than RES and HIH. Ewes fed HSe had greater (P \u3c 0.01) milk yield (g/d and mL/d) than ASe, and CON and HIH had greater (P \u3c 0.01) yield than RES. Milk protein (%) was greater (P ≤ 0.01) in RES compared with CON or HIH. Ewes fed HSe had greater (P \u3c 0.01) milk Se (µg/g and mg/d) than ASe on each sampling day. Milk from CON and HIH ewes had greater (P \u3c 0.01) total solids-not-fat, lactose, protein, and milk urea N than RES. Total Se was greater (P = 0.02) in milk from ewes fed the CON diet compared with RES. Somatic cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P \u3c 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met