Review: Methods and biomarkers to investigate intestinal function and health in pigs

Society is becoming increasingly critical of animal husbandry due to its environmental impact and issues involving animal health and welfare including scientific experiments conducted on farm animals. This opens up two new fields of scientific research, the development of non- or minimally invasive (1) methods and techniques using faeces, urine, breath or saliva sampling to replace existing invasive models, and (2) biomarkers reflecting a disease or malfunction of an organ that may predict the future outcome of a pig’s health, performance or sustainability. To date, there is a paucity of non- or minimally invasive methods and biomarkers investigating gastrointestinal function and health in pigs. This review describes recent literature pertaining to parameters that assess gastrointestinal functionality and health, tools currently used to investigate them, and the development or the potential to develop new non- and minimally invasive methods and/or biomarkers in pigs. Methods described within this review are those that characterise gastrointestinal mass such as the citrulline generation test, intestinal protein synthesis rate, first pass splanchnic nutrient uptake and techniques describing intestinal proliferation, barrier function and transit rate, and microbial composition and metabolism. An important consideration is gut health, and several molecules with the potential to act as biomarkers of compromised gut health in pigs are reported. Many of these methods to investigate gut functionality and health are considered ‘gold standards’ but are invasive. Thus, in pigs, there is a need to develop and validate non-invasive methods and biomarkers that meet the principles of the 3 R guidelines, which aim to reduce and refine animal experimentation and replace animals where possible

Adverse effects of nutritional programming during prenatal and early postnatal life, some aspects of regulation and potential prevention and treatments

International audienceNutritional programming, regulation and some ways for prevention/treatment to ameliorate or normalize adverse outcomes of programming are discussed. Epidemiological studies in human and animal experiments showed that nutrition during fetal and neonatal life may lead to related disorders in adulthood. But several argues may question its validity arising the question of the adequate models used to reproduce human situations. Protein level in milk formula intake by infant during neonatal life is discussed. Body weight at birth reflects the product growth trajectory during fetal life. Low birth weight is considered as the result of an adverse growth trajectory and is often associated with later metabolic diseases in adult age. But, the sum of prenatal growth trajectory, rapid growth in early infancy (catch up growth), early adiposity rebound in childhood must be considered to determine the origins of later diseases in adulthood. The review focuses the regulation of nutritional imprinting on hormonal and epigenetic mechanisms which are complementary. The I-IPA axis and GH-IGF axis may have a crucial role in the regulation induced by nutritional programming. The persistent alterations seem to be a consequence, at least in part, of elevated insulin levels during 'critical periods" of pre- and early postnatal development. Also, leptin seems to play an important role in this complex system. New knowledge about these mechanisms involved suggest the development of new, rational, and effective preventive and/or therapeutic options before and/or after birth. Thus, early infancy may provide an opportunity for intervention aimed at reducing later disease risk

Adverse effects of nutritional programming during prenatal and early postnatal life, some aspects of regulation and potential prevention and treatments

International audienceNutritional programming, regulation and some ways for prevention/treatment to ameliorate or normalize adverse outcomes of programming are discussed. Epidemiological studies in human and animal experiments showed that nutrition during fetal and neonatal life may lead to related disorders in adulthood. But several argues may question its validity arising the question of the adequate models used to reproduce human situations. Protein level in milk formula intake by infant during neonatal life is discussed. Body weight at birth reflects the product growth trajectory during fetal life. Low birth weight is considered as the result of an adverse growth trajectory and is often associated with later metabolic diseases in adult age. But, the sum of prenatal growth trajectory, rapid growth in early infancy (catch up growth), early adiposity rebound in childhood must be considered to determine the origins of later diseases in adulthood. The review focuses the regulation of nutritional imprinting on hormonal and epigenetic mechanisms which are complementary. The I-IPA axis and GH-IGF axis may have a crucial role in the regulation induced by nutritional programming. The persistent alterations seem to be a consequence, at least in part, of elevated insulin levels during 'critical periods" of pre- and early postnatal development. Also, leptin seems to play an important role in this complex system. New knowledge about these mechanisms involved suggest the development of new, rational, and effective preventive and/or therapeutic options before and/or after birth. Thus, early infancy may provide an opportunity for intervention aimed at reducing later disease risk

Proteome and radioimmunoassay analyses of pituitary hormones and proteins in response to feed restriction of dairy cows

The hypothalamic-pituitary system controls homeostasis during feed energy reduction. In order to examine which pituitary proteins and hormone variants are potentially associated with metabolic adaptation, pituitary glands from ad libitum and energy restrictively fed dairy cows were characterized using RIA and 2-DE followed by MALDI-TOF-MS. We found 64 different spots of regulatory hormones: growth hormone (44), preprolactin (16), luteinizing hormone (LH) (1), thyrotropin (1), proopiomelanocortin (1) and its cleavage product lipotropin (1), but none of these did significantly differ between feeding groups. Quantification of total pituitary LH and prolactin concentrations by RIA confirmed the results obtained by proteome analysis. Also, feed energy restriction provoked increasing non-esterified fatty acid, decreasing prolactin, but unaltered glucose, LH and growth hormone plasma concentrations. Energy restriction decreased the expression of glial fibrillary acidic protein, triosephosphate isomerase, purine-rich element-binding protein A and elongation factor Tu, whereas it increased expression of proline synthetase co-transcribed homolog, peroxiredoxin III, beta-tubulin and annexin A5 which is involved in the hormone secretion process. Our results indicate that in response to feed energy restriction the pituitary reservoir of all posttranslationally modified hormone forms remains constant. Changing plasma hormone concentrations are likely attributed to a regulated releasing process from the gland into the blood

The energy expenditure of 2 Holstein cow strains in an organic grazing system

Until recently, measurements of energy expenditure (EE; herein defined as heat production) in respiration chambers did not account for the extra energy requirements of grazing dairy cows on pasture. As energy is first limiting in most pasture-based milk production systems, its efficient use is important. Therefore, the aim of the present study was to compare EE, which can be affected by differences in body weight (BW), body composition, grazing behavior, physical activity, and milk production level, in 2 Holstein cow strains. Twelve Swiss Holstein-Friesian (HCH; 616 kg of BW) and 12 New Zealand Holstein-Friesian (HNZ; 570 kg of BW) cows in the third stage of lactation were paired according to their stage of lactation and kept in a rotational, full-time grazing system without concentrate supplementation. After adaption, the daily milk yield, grass intake using the alkane double-indicator technique, nutrient digestibility, physical activity, and grazing behavior recorded by an automatic jaw movement recorder were investigated over 7d. Using the (13)C bicarbonate dilution technique in combination with an automatic blood sampling system, EE based on measured carbon dioxide production was determined in 1 cow pair per day between 0800 to 1400 h. The HCH were heavier and had a lower body condition score compared with HNZ, but the difference in BW was smaller compared with former studies. Milk production, grass intake, and nutrient digestibility did not differ between the 2 cow strains, but HCH grazed for a longer time during the 6-h measurement period and performed more grazing mastication compared with the HNZ. No difference was found between the 2 cow strains with regard to EE (291 ± 15.6 kJ) per kilogram of metabolic BW, mainly due to a high between-animal variation in EE. As efficiency and energy use are important in sustainable, pasture-based, organic milk production systems, the determining factors for EE, such as methodology, genetics, physical activity, grazing behavior, and pasture quality, should be investigated and quantified in more detail in future studies

Maturation of endogenous glucose production in preterm and term calves

Glucose disposability is often impaired in neonatal calves and even more in preterm calves. The objective of this study was to investigate ontogenic maturation of endogenous glucose production (eGP) in calves and its effects on postnatal glucose homeostasis. Calves (n = 7 per group) were born preterm (PT; delivered by section 9 d before term) or at term (T; spontaneous vaginal delivery), or spontaneously born and fed colostrum for 4 d (TC). Blood samples were taken immediately after birth and before and 2h after feeding at 24h after birth (PT; T) or on d 4 of life (TC) to determine metabolic and endocrine changes. After birth (PT and T) or on d 3 of life (TC), fasted calves were gavaged with deuterium-labeled water to determine gluconeogenesis (GNG) and intravenously infused with [U(13)C]-glucose to measure eGP and glucose oxidation (GOx) in blood plasma. After slaughter at 26h after birth (PT, T) or on d 4 of life (TC), glycogen concentrations in liver and hepatic mRNA concentrations and enzyme activities of pyruvate carboxylase, phosphoenolpyruvate carboxykinase (PEPCK), and glucose-6-phosphatase were measured. Preterm calves had the lowest plasma concentrations of cortisol and 3,5,3'-triiodothyronine at birth. Plasma glucose concentrations from d 1 to 2 decreased more, but plasma concentrations of lactate and urea and glucagon:insulin ratio were higher in PT than in T and TC calves. The eGP, GNG, GOx, as well as hepatic glycogen concentrations and PEPCK activities, were lowest in PT calves. Results indicate impaired glucose homeostasis due to decreased eGP in PT calves and maturation of eGP with ontogenic development

Intestinal glucose absorption but not endogenous glucose production differs between colostrum- and formula-fed neonatal calves

Glucose supply markedly changes during the transition to extrauterine life. In this study, we investigated diet effects on glucose metabolism in neonatal calves. Calves were fed colostrum (C; n = 7) or milk-based formula (F; n = 7) with similar nutrient content up to d 4 of life. Blood plasma samples were taken daily before feeding and 2 h after feeding on d 4 to measure glucose, lactate, nonesterified fatty acids, protein, urea, insulin, glucagon, and cortisol concentrations. On d 2, additional blood samples were taken to measure glucose first-pass uptake (FPU) and turnover by oral [U-(13)C]-glucose and i.v. [6,6-(2)H(2)]-glucose infusion. On d 3, endogenous glucose production and gluconeogenesis were determined by i.v. [U-(13)C]-glucose and oral deuterated water administration after overnight feed deprivation. Liver tissue was obtained 2 h after feeding on d 4 and glycogen concentration and activities and mRNA abundance of gluconeogenic enzymes were measured. Plasma glucose and protein concentrations and hepatic glycogen concentration were higher (P < 0.05), whereas plasma urea, glucagon, and cortisol (d 2) concentrations as well as hepatic pyruvate carboxylase mRNA level and activity were lower (P < 0.05) in group C than in group F. Orally administered [U-(13)C]-glucose in blood was higher (P < 0.05) but FPU tended to be lower (P < 0.1) in group C than in group F. The improved glucose status in group C resulted from enhanced oral glucose absorption. Metabolic and endocrine changes pointed to elevated amino acid degradation in group F, presumably to provide substrates to meet energy requirements and to compensate for impaired oral glucose uptake