Determination of oxytocin in milk of cows administered oxytocin

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Analytical and physiological validation of an enzyme immunoassay to measure oxytocin in dog, wolf, and human urine samples

Oxytocin (OT) promotes pro-sociality, bonding, and cooperation in a variety of species. Measuring oxytocin metabolite (OTM) concentrations in urine or saliva provides intriguing opportunities to study human and animal behaviour with minimal disturbance. However, a thorough validation of analytical methods and an assessment of the physiological significance of these measures are essential. We conducted an analytical validation of a commercial Enzyme Immunoassay (EIA; Arbor OT assay kit) to measure OTM concentrations in dog, wolf, and human urine samples. To test the assay's ability to detect changes in OTM concentrations, we administered oxytocin intranasally to 14 dogs. Assay performance with regard to parallelism was acceptable. Assay accuracy and extraction efficiency for dog and wolf samples were comparable to a previously validated assay (Enzo OT assay kit) but variation was smaller for human samples. Binding sensitivity and antibody specificity were better in the Arbor assay. Average OTM concentrations were more than twice as high as in comparable samples measured with the Enzo assay, highlighting a lack of comparability of absolute values between different assays. Changes in OTM concentrations after intranasal treatment were detected reliably. The Arbor assay met requirements of a "fit-for-purpose" validation with improvement of several parameters compared to the Enzo assay.

Interrelationships between metabolic hormones, leptin and ghrelin, and oil-related contaminants in control of oxytocin and prostaglandin F release by feline ovaries

We examined the effects of metabolic hormones leptin and ghrelin, and the oil-related environmental contaminants toluene and xylene on the release of ovarian hormones by gravid and non-gravid cats, as well as the functional interrelationships between metabolic hormones and contaminants. Ovarian fragments of non-gravid cats were cultured with and without leptin and toluene. Next, ovarian fragments of either non-gravid or gravid animals were cultured with and without ghrelin and xylene. Oxytocin (OT) and prostaglandin F (PGF) release was measured using ELISA. We confirm ovarian OT and PGF production by feline ovary, demonstrate the involvement of leptin and ghrelin in controlling OT and PGF release, show the direct influence of toluene and xylene on feline ovarian secretory activity, indicate the ability of leptin and ghrelin to mimic and promote the main contaminant effects, demonstrate that oil-related contaminants can prevent and even invert the effects of leptin and ghrelin on the ovary, and suggest the gravidity-associated changes in ability of ghrelin to promote xylene action on PGF (but not to OT), but not in basic ovarian OT and PGF release and their response to ghrelin or xylene.

Dairy cattle welfare as a result of human-animal relationship – a review

Despite the various concepts of human-animal relationship, the welfarist approach to this problem is one of the most often considered in theory and used in practice. When dealing with issues related to dairy cattle welfare (DCW), it is necessary to take into account both the reality characteristic for animals used to obtain milk (e.g. the problem of automatic milking of cows) and for slaughter cattle (e.g. slaughter of culled animals). It is not surprising, therefore, that issues related to DCW are the focus of the attention of the public, researchers, breeders as well as the dairy and meat industries. The aim of this article was to possibly most comprehensively cover the above-mentioned issues, although due to its huge scope it was obviously necessary to limit the article to what I think are currently most important issues. That is why in the review I (1) characterized the issues related to the division of human responsibility for DCW; (2) discussed the importance of technology to human-animal relationship; (3) elaborated the matter of stress, emotionality of animals and their cognitive abilities in the aspect of “negative” and “positive” DCW; (4) considered the possibilities of non-invasive assessment of animal welfare in the future and (5) discussed topics related to improving the conditions of the slaughter of animals. In summary, it was proposed paying more attention than has been paid until now, to the assessment of positive DCW in scientific research and breeding practice. I also drew attention to the necessity of reliable information flow on the line of the breeder/milk producer - industry - consumer, as negligence in this area is one of the reasons for public disinformation regarding the level of animal welfare.

Associations Between Nurse-Guided Variables and Plasma Oxytocin Trajectories in Premature Infants During Initial Hospitalization

BACKGROUND

Oxytocin (OT) is a social hormone that may help researchers understand how nurse-guided interventions during initial infant hospitalization, such as supporting human milk expression, promoting comforting touch, and reducing exposure to stressors, affect preterm brain development.

PURPOSE

To determine whether factors related to human milk, touch, or stressor exposure are related to plasma OT trajectories in premature infants.

METHODS

Plasma from 33 premature infants, born gestational ages 25 to (Equation is included in full-text article.)weeks, was collected at 14 days of life and then weekly until 34 weeks' corrected gestational age (CGA). Variables related to feeding volumes of human milk and formula; touch, as indexed by skin-to-skin contact (SSC) and swaddled holding; and clinical stressors were extracted from the electronic medical record. Linear mixed-models tested associations between nurse-guided variables and plasma OT trajectories.

RESULTS

In the final model, same-day SSC was positively related not only to plasma OT levels at 27 weeks' CGA (β= .938, P = .002) but also to a decline in plasma OT levels over time (β=-.177, P = .001). Volume of enteral feeds (mL/kg/d), its interaction with CGA, and number of stressful procedures were not statistically significant (β= .011, P = .077; β=-.002, P = .066; and β= .007, P = .062, respectively).

IMPLICATIONS FOR PRACTICE

Nurse-guided interventions are associated with infant plasma OT levels, suggesting nurses may impact the neurobiology of the developing premature infant.

IMPLICATIONS FOR RESEARCH

Replication with larger sample sizes and randomized controlled trial designs is needed to test effects of specific nursing interventions on infant OT.

Intestinal transepithelial permeability of oxytocin into the blood is dependent on the receptor for advanced glycation end products in mice

Plasma oxytocin (OT) originates from secretion from the pituitary gland into the circulation and from absorption of OT in mother's milk into the blood via intestinal permeability. However, the molecular mechanism underlying the absorption of OT remains unclear. Here, we report that plasma OT concentrations increased within 10 min after oral delivery in postnatal day 1-7 mice. However, in Receptors for Advanced Glycation End Products (RAGE) knockout mice after postnatal day 3, an identical OT increase was not observed. In adult mice, plasma OT was also increased in a RAGE-dependent manner after oral delivery or direct administration into the intestinal tract. Mass spectrometry evaluated that OT was absorbed intact. RAGE was abundant in the intestinal epithelial cells in both suckling pups and adults. These data highlight that OT is transmitted via a receptor-mediated process with RAGE and suggest that oral OT supplementation may be advantageous in OT drug development.

Neohormones in milk

Neohormone systems evolved specifically to regulate those mammalian traits, such as internal fertilization, pregnancy and lactation, which have proved to be central to the success, environmental independence, and adaptability of mammals as a vertebrate group. Neohormones such as oxytocin or relaxin are not only involved in the regulation of mammary gland development and function, but are also significant components of milk itself. Particularly for the latter hormone, it has been shown for the pig that relaxin in the first milk is taken up by the gastrointestinal tract of the offspring, enters the neonatal circulation and can have specific physiological and epigenetic effects on target organs such as the female reproductive system. Nevertheless, there are large gaps in our knowledge and understanding of such lactocrine systems especially in regard to other neohormones, species, and neonatal organ systems.

Colostrum oxytocin modulates cellular stress response, inflammation, and autophagy markers in newborn rat gut villi

Little is known about the role of oxytocin (OT) in colostrum during early gut colonization. We previously showed that transient OT receptor (OTR) expression on newborn rat enterocytes coincides with the milk-suckling period, and that OT activates endoplasmic reticulum stress sensors in cultured enterocytes. Here, we explored whether colostrum-OT attenuates stress in newborn villi primed and unprimed by colostrum by measuring levels of stress markers including BiP (an ER chaperone), eIF2a (translation initiation factor), and pPKR (eIF2a kinase). We also measured two inflammation-signaling proteins NF-κB and its inhibitor IκB. To test the impact of colostrum on autophagy, we measured a marker of autophagy initiation, LC3A. Colostrum increased inactive p-eIF2a, p-PKR and IκB and reduced p-IκB, BiP and LC3A. LPS increased and OT decreased p-IkB. BiP (GRP78) was higher in unprimed than primed villi. Together, these data suggest that colostrum OT attenuates the impact of inflammation on postnatal gut villi and that OT enhances autophagy to protect against amino acid insufficiency-induced stress during the interval between birth and the first feeding.

Calming Cycle Theory and the Co-Regulation of Oxytocin

The biological functions of oxytocin in attachment and bonding between mother and infant in parturition and breastfeeding and between adults have been studied extensively. However, most current authors have proposed that infant attachment to the mother is learned through operant conditioning mechanisms via the infant's brain and central nervous system. We propose that oxytocin levels in the mother and infant are co-regulated by emotional connection or disconnection, and that the autonomic co-conditioning learning mechanism can be exploited to change a negative physiological and behavioral response between mother and infant into a positive one. Lack of efficacy and scalability of child development therapies that have come out of the attachment theoretical framework have prompted calls for new ideas. Here, we review calming cycle theory, which takes a new view of the emotional relationship of mother and infant, and predicts ways to positively intervene when problems arise. The theory builds upon the research and ideas of Pavlov and his followers and proposes that subcortical Pavlovian co-conditioning of the autonomic nervous systems of mother and infant is the key to maintaining emotional connection between the two and to shaping emotional behavior of the infant into adulthood. We review evidence in support of calming cycle theory from a randomized controlled trial of Family Nurture Intervention (FNI), which is designed to overcome adverse emotional, behavioral, and developmental outcomes in prematurely born infants. Finally, we discuss the role of visceral oxytocin and emotional behavior, and that the conditional mother-infant relationship may affect behavioral changes through anti-inflammatory gut-brain stem vagal signaling.

Method for collecting mouse milk without exogenous oxytocin stimulation

It has been reported that breast-feeding more than 6 months strongly decreases the risk of allergy, diabetes, obesity, and hypertension in humans. In order to understand the mechanisms responsible for this benefit, it is important to evaluate precisely the composition of maternal milk, especially in response to environmental cues. Mouse models offer a unique opportunity to study the impact of maternal milk composition on the development and health of offspring. Oxytocin injection of the dam is usually used to stimulate milk ejection; however, exogenous oxytocin might have deleterious effects under some experimental conditions by modifying milk content as well as the physiology and behavior of the dam. Taking advantage of the natural stimulation of the mammary gland that occurs after the reunion of a dam that has been separated from her pups, we developed a new procedure to collect mouse milk without the injection of oxytocin. This method is easy to use, low-cost ,and non-invasive. Moreover, it provides a sufficient amount of milk for use in a wide range of biological analyses.

Oxytocin regulates gastrointestinal motility, inflammation, macromolecular permeability, and mucosal maintenance in mice

Enteric neurons express oxytocin (OT); moreover, enteric neurons and enterocytes express developmentally regulated OT receptors (OTRs). Although OT (with secretin) opposes intestinal inflammation, physiological roles played by enteric OT/OTR signaling have not previously been determined. We tested hypotheses that OT/OTR signaling contributes to enteric nervous system (ENS)-related gastrointestinal (GI) physiology. GI functions and OT effects were compared in OTR-knockout (OTRKO) and wild-type (WT) mice. Stool mass and water content were greater in OTRKO mice than in WT. GI transit time in OTRKO animals was faster than in WT; OT inhibited in vitro generation of ENS-dependent colonic migrating motor complexes in WT but not in OTRKO mice. Myenteric neurons were hyperplastic in OTRKO animals, and mucosal exposure to cholera toxin (CTX) in vitro activated Fos in more myenteric neurons in OTRKO than WT than in WT mice; OT inhibited the CTX response in WT but not in OTRKO mice. Villi and crypts were shorter in OTRKO than in WT mice, and transit-amplifying cell proliferation in OTRKO crypts was deficient. Macromolecular intestinal permeability in OTRKO was greater than WT mice, and experimental colitis was more severe in OTRKO mice; moreover, OT protected WT animals from colitis. Observations suggest that OT/OTR signaling acts as a brake on intestinal motility, decreases mucosal activation of enteric neurons, and promotes enteric neuronal development and/or survival. It also regulates proliferation of crypt cells and mucosal permeability; moreover OT/OTR signaling is protective against inflammation. Oxytocinergic signaling thus appears to play an important role in multiple GI functions that are subject to neuronal regulation.

Validation of an enzyme-linked immunoassay (ELISA) for plasma oxytocin in a novel mammal species reveals potential errors induced by sampling procedure

BACKGROUND

The neuropeptide oxytocin is increasingly the focus of many studies investigating human and animal social behaviours and diseases. However, interpretation and comparison of results is made difficult by a lack of consistent methodological approaches towards analysing this hormone.

NEW METHOD

This study determined the sample collection and analysis protocols that cause the least amounts of protocol dependant variation in plasma oxytocin concentrations detected by ELISA. The effect of vacutainer type, sample extraction prior to analysis and capture and restraint protocol were investigated while validating an assay protocol for two novel species, grey seals (Halichoerus grypus) and harbour seals (Phoca vitulina).

RESULTS

Where samples are extracted prior to analysis, vacutainer type (EDTA mean: 8.25±0.56 pg/ml, heparin mean: 8.25±0.62 pg/ml, p=0.82), time taken to obtain a sample and restraint protocol did not affect the concentration of oxytocin detected. However, concentrations of oxytocin detected in raw plasma samples were significantly higher than those in extracted samples, and varied significantly with vacutainer type (EDTA mean: 534.4±43.7 pg/ml, heparin mean: 300.9±19.6 pg/ml, p<0.001) and capture and restraint methodology. There was no relationship between oxytocin concentrations detected in raw and extracted plasma (p=0.25).

COMPARISON WITH EXISTING METHOD(S)

Over half the reviewed published studies analysing plasma oxytocin use raw plasma and different vacutainer types are used without consistency or justification through-out the literature.

CONCLUSIONS

We caution that studies using raw plasma are likely to over estimate oxytocin concentrations, cannot be used to accurately infer true values via correlations and are susceptible to variation according vacutainer type.

The impact of oxytocin on the hemodynamic features of the milk vein in dairy cows: a Color Doppler investigation

This manuscript investigates, by Color Doppler ultrasonography, the basal hemodynamic features of the left cranial epigastric vein (milk vein) of 210 Holstein-Friesian cows, throughout lactation. Blood velocity, diameter, blood flow of the milk vein (before and after milking) and milk production detected in cows administered oxytocin were compared with the same parameters found in untreated cows. Blood velocity tended to decrease throughout lactation as did milk production, whereas both diameters and blood flows tended to increase towards the end of the study. All the four parameters showed higher values in the treated cows than in the untreated ones. This study provides a detailed picture of the hemodynamic features of the milk vein of the dairy cows throughout lactation and suggest that oxytocin may exert a vasodilatory effect, in vivo, at least on the cranial epigastric vein of the dairy cow.

Development, validation and data quality assurance of screening methods: a case study

Despite the growing importance of qualitative screening tests in routine laboratories involved in the EU official control, their validation is not as deeply explained in Commission Decision 2002/657/EC as the validation of quantitative confirmatory methods. At the same time, the issue of quality assurance of screening assays defining internal quality control (IQC) procedures as required by accreditation bodies is undoubtedly less developed in this analytical field. As an example the present study describes the development, the validation and the IQC implemented for a commercial enzyme linked immunosorbent assay (ELISA) able to detect 17-α-19-nortestosterone (α-NT) and 17-β-19-nortestosterone (β-NT) isomers in bullock urine. In order to select a suitable sample treatment, two SPE purification protocols were preliminary compared. The chosen method was therefore fully validated determining the mandatory parameters required by Commission Decision 2002/657/EC: specificity, detection capability and robustness. An in-depth discussion was carried out illustrating the possible validation approaches and their implications especially in the assessment of the key performance characteristic: detection capability. Finally, the control charts implemented for continuous method verification during analyses of real samples were reported.

The bovine milk proteome: cherishing, nourishing and fostering molecular complexity. An interactomics and functional overview

Bovine milk represents an essential source of nutrients for lactating calves and a key raw material for human food preparations. A wealth of data are present in the literature dealing with massive proteomic analyses of milk fractions and independent targeted studies on specific groups of proteins, such as caseins, globulins, hormones and cytokines. In this study, we merged data from previous investigations to compile an exhaustive list of 573 non-redundant annotated protein entries. This inventory was exploited for integrated in silico studies, including functional GO term enrichment (FatiGO/Babelomics), multiple pathway and network analyses. As expected, most of the milk proteins were grouped under pathways/networks/ontologies referring to nutrient transport, lipid metabolism and objectification of the immune system response. Notably enough, another functional family was observed as the most statistically significant one, which included proteins involved in the induction of cellular proliferation processes as well as in anatomical and haematological system development. Although the latter function for bovine milk proteins has long been postulated, studies reported so far mainly focused on a handful of molecules and missed the whole overview resulting from an integrated holistic analysis. A preliminary map of the bovine milk proteins interactome was also built up, which will be refined in future as result of the widespread use of quantitative methods in protein interaction studies and consequent reduction of false-positives within associated databases.