Mechanisms Underlying the Expansion and Functional Maturation of ß-Cells in Newborns: Impact of the Nutritional Environment.

The functional maturation of insulin-secreting ß-cells is initiated before birth and is completed in early postnatal life. This process has a critical impact on the acquisition of an adequate functional ß-cell mass and on the capacity to meet and adapt to insulin needs later in life. Many cellular pathways playing a role in postnatal ß-cell development have already been identified. However, single-cell transcriptomic and proteomic analyses continue to reveal new players contributing to the acquisition of ß-cell identity. In this review, we provide an updated picture of the mechanisms governing postnatal ß-cell mass expansion and the transition of insulin-secreting cells from an immature to a mature state. We then highlight the contribution of the environment to ß-cell maturation and discuss the adverse impact of an in utero and neonatal environment characterized by calorie and fat overload or by protein deficiency and undernutrition. Inappropriate nutrition early in life constitutes a risk factor for developing diabetes in adulthood and can affect the ß-cells of the offspring over two generations. A better understanding of these events occurring in the neonatal period will help developing better strategies to produce functional ß-cells and to design novel therapeutic approaches for the prevention and treatment of diabetes.

Feline neonatology: From birth to commencement of weaning - what to know for successful management.

PRACTICAL RELEVANCE: Despite considerable interest in the field of companion animal reproduction, feline neonatology remains largely unstudied. This contrasts with the need for a more professional veterinary approach to newborn kittens and feline husbandry, across the pet, breeding cattery and rescue shelter settings, to reduce kitten mortality. GLOBAL IMPORTANCE: Feline neonatology has relevance for veterinarians around the world as cats are continuing to become established as popular companion animals. CLINICAL CHALLENGES: Perinatal mortality in cats is remarkably high. Therefore, adequate neonatal evaluation and assistance at birth, careful monitoring of kittens in the vulnerable period until weaning begins, assessment of maternal factors and well-informed management of orphans are crucial in helping to reduce kitten losses. AIM: This review aims to deepen the basic knowledge of the veterinary clinical team regarding the characteristics of feline newborns under normal conditions at birth through to the commencement of weaning. Much of the information is also relevant to breeders and rescue/shelter caregivers. EVIDENCE BASE: In compiling the present review, the authors have drawn on specific feline research data, where available, complemented by data extrapolated from scientific publications on newborn dogs, and also their own and their colleagues' professional clinical experience.

A. muciniphila Supplementation in Mice during Pregnancy and Lactation Affects the Maternal Intestinal Microenvironment.

During pregnancy and lactation, considerable factors that affect the maternal microbiome are associated with the advancement of numerous diseases, which can potentially affect offspring health. Probiotics have shown potential for the maintenance of microbiota homeostasis of mothers in this period. The specific objective of this study was to investigate whether the application of Akkermansia muciniphila (A. muciniphila) during pregnancy and lactation impacts maternal and offspring health. Here we show that dams fed with A. muciniphila is safe, enhances the intestinal barrier and alters gut microbiota composition and diversity at the end of lactation, including the significant enrichment of A. muciniphila and Ruminococcus_1 in offspring from probiotic-fed dams. However, compared with the control group, the fecal metabolites of the A. muciniphila group only changed slightly. Additionally, A. muciniphila supplementation did not significantly increase the abundance of A. muciniphila in the fecal microbiota of offspring mice. Compared with the control group, the fecal metabolic profile of three-week-old offspring of mice fed with A. muciniphila were significantly changed, containing the D-glutamine and D-glutamate metabolism pathways. These results provided evidence that A. muciniphila supplementation in mice during pregnancy and lactation is safe and seemed to have a more beneficial effect on dams. In the future, using probiotics to regulate maternal microbiomes during pregnancy and lactation could be shown to have a more lasting and beneficial effect.

The imprinted Zdbf2 gene finely tunes control of feeding and growth in neonates.

Genomic imprinting refers to the mono-allelic and parent-specific expression of a subset of genes. While long recognized for their role in embryonic development, imprinted genes have recently emerged as important modulators of postnatal physiology, notably through hypothalamus-driven functions. Here, using mouse models of loss, gain and parental inversion of expression, we report that the paternally expressed Zdbf2 gene controls neonatal growth in mice, in a dose-sensitive but parent-of-origin-independent manner. We further found that Zdbf2-KO neonates failed to fully activate hypothalamic circuits that stimulate appetite, and suffered milk deprivation and diminished circulating Insulin Growth Factor 1 (IGF-1). Consequently, only half of Zdbf2-KO pups survived the first days after birth and those surviving were smaller. This study demonstrates that precise imprinted gene dosage is essential for vital physiological functions at the transition from intra- to extra-uterine life, here the adaptation to oral feeding and optimized body weight gain.

Review: Improving the performance of neonatal piglets.

Newborn piglets have a high incidence of preweaning mortality that is not only associated with low birth weights but also with the presence of intra-uterine growth-restricted (IUGR) piglets. Such IUGR piglets are commonly seen in litters from hyperprolific sows as a result of insufficient placental transfer of nutrients. Nutritional strategies can be used prior to and during gestation to enhance foetal development and can also be implemented in the transition period to reduce the duration of farrowing and increase colostrum yield. Recent findings showed that the energy status of sows at the onset of farrowing is crucial to diminish stillbirth rate. Newborn piglets often fail to consume enough colostrum to promote thermostability and subsequent growth, and this is particularly problematic in very large litters when there are fewer available teats than the number of suckling piglets. One injection of 75 IU of oxytocin approximately 14 h after farrowing can prolong the colostral phase, hence increasing the supply of immunoglobulins to piglets. Nevertheless, assistance must be provided to piglets after birth in order to increase their chance of survival. Various approaches can be used, such as: (1) optimising the farrowing environment, (2) supervising farrowing and assisting newborn piglets, (3) using cross-fostering techniques, (4) providing nurse sows, and 5) providing artificial milk. Although research advances have been made in developing feeding and management strategies for sows that increase performance of their newborn piglets, much work still remains to be done to ensure that maximal outcomes are achieved.

Pulmonary acini exhibit complex changes during postnatal rat lung development.

Pulmonary acini represent the functional gas-exchanging units of the lung. Due to technical limitations, individual acini cannot be identified on microscopic lung sections. To overcome these limitations, we imaged the right lower lobes of instillation-fixed rat lungs from postnatal days P4, P10, P21, and P60 at the TOMCAT beamline of the Swiss Light Source synchrotron facility at a voxel size of 1.48 µm. Individual acini were segmented from the three-dimensional data by closing the airways at the transition from conducting to gas exchanging airways. For a subset of acini (N = 268), we followed the acinar development by stereologically assessing their volume and their number of alveoli. We found that the mean volume of the acini increases 23 times during the observed time-frame. The coefficients of variation dropped from 1.26 to 0.49 and the difference between the mean volumes of the fraction of the 20% smallest to the 20% largest acini decreased from a factor of 27.26 (day 4) to a factor of 4.07 (day 60), i.e. shows a smaller dispersion at later time points. The acinar volumes show a large variation early in lung development and homogenize during maturation of the lung by reducing their size distribution by a factor of 7 until adulthood. The homogenization of the acinar sizes hints at an optimization of the gas-exchange region in the lungs of adult animals and that acini of different size are not evenly distributed in the lungs. This likely leads to more homogeneous ventilation at later stages in lung development.

Elevated fear responses to threatening cues in rats with early life stress is associated with greater excitability and loss of gamma oscillations in ventral-medial prefrontal cortex.

Stress experienced early in development can have profound influences on developmental trajectories and ultimately behaviors in adulthood. Potent stressors during brain maturation can profoundly disrupt prefrontal cortical areas in particular, which can set the stage for prefrontal-dependent alterations in fear regulation and risk of drug abuse in adulthood. Despite these observations, few studies have investigated in vivo signaling in prefrontal signals in animals with a history of early life stress (ELS). Here, rats with ELS experienced during the first post-natal week were then tested on a conditioned suppression paradigm during adulthood. During conditioned suppression, electrophysiological recordings were made in the ventral medial prefrontal cortex (vmPFC) during presentations of a fear-associated cue that resolved both single-unit activity and local field potentials (LFPs). Relative to unstressed controls, ELS-experienced rats showed greater fear-related suppression of lever pressing. During presentations of the fear-associated cue (CS+), neurons in the vmPFC of ELS animals showed a significant increase in the probability of excitatory encoding relative to controls, and excitatory phasic responses in the ELS animals were reliably of higher magnitude than Controls. In contrast, vmPFC neurons in ELS subjects better discriminated between the shock-associated CS+ and the neutral ("safe") CS- cue than Controls. LFPs recorded in the same locations revealed that high gamma band (65-95 Hz) oscillations were strongly potentiated in Controls during presentation of the fear-associated CS+ cue, but this potentiation was abolished in ELS subjects. Notably, no other LFP spectra differed between ELS and Controls for either the CS+ or CS-. Collectively, these data suggest that ELS experience alters the neurobehavioral functions of PFC in adulthood that are critical for processing fear regulation. As such, these alterations may also provide insight into increased susceptibility to other PFC-dependent processes such as risk-based choice, motivation, and regulation of drug use and relapse in ELS populations.

Cardiopulmonary effects and recovery characteristics associated with 2 sedative protocols for assisted ventilation in healthy neonatal foals.

Neonatal foals may require prolonged sedation to permit ventilatory support in the first few days of life. The objective of this study was to evaluate and compare the cardiopulmonary effects and clinical recovery characteristics of 2 sedative/analgesia protocols in healthy foals receiving assisted ventilation. Foals were randomized to receive dexmedetomidine, butorphanol, and propofol (DBP) or midazolam, butorphanol, and propofol (MBP) during a 24-hour period. Infusion rates of dexmedetomidine, midazolam, and propofol were adjusted and propofol boluses administered according to set protocols to maintain optimal sedation and muscle relaxation. Ventilatory support variables were adjusted to preset targets. Physiologic variables were recorded, cardiac output (CO) measured (thermodilution), and arterial and mixed venous blood collected for gas analysis at intervals up to 24 hours. Foals in group DBP received dexmedetomidine [2.4 ± 0.5 µg/kg body weight (BW) per hour], butorphanol (13 µg/kg BW per hour), and propofol (6.97 ± 0.86 mg/kg BW per hour), whereas foals in group MBP received midazolam (0.14 ± 0.04 mg/kg BW per hour), butorphanol (13 µg/kg BW per hour), and propofol (5.98 ± 1.33 mg/kg BW per hour). Foals in the DBP group received significantly more propofol boluses (9.0 ± 3.0) than those in the MBP group (4.0 ± 2.0). Although physiologic variables remained within acceptable limits, heart rate (HR), mean arterial pressure (MAP), and cardiac index (CI) were lower in foals in the DBP group than in the MBP group. Times to sternal recumbency, standing, and nursing were significantly shorter in the DBP than MBP group. We found that MBP and DBP protocols are suitable to assist ventilatory support in neonatal foals, although MBP results in a prolonged recovery compared to DBP.

Les poulains nouveau-nés peuvent nécessiter une sédation prolongée pour permettre une assistance ventilatoire au cours des premiers jours de vie. L'objectif de cette étude était d'évaluer et de comparer les effets cardio-pulmonaires et les caractéristiques de récupération clinique de deux protocoles sédatifs/analgésiques chez des poulains sains recevant une ventilation assistée. Les poulains ont été randomisés pour recevoir de la dexmédétomidine, du butorphanol et du propofol (DBP) ou du midazolam, du butorphanol et du propofol (MBP) pendant une période de 24 heures. Les débits de perfusion de dexmédétomidine, de midazolam et de propofol ont été ajustés et des bolus de propofol ont été administrés selon des protocoles définis pour maintenir une sédation et une relaxation musculaire optimales. Les variables d'assistance ventilatoire ont été ajustées à des cibles prédéfinies. Les variables physiologiques ont été enregistrées, le débit cardiaque (CO) mesuré (thermodilution) et le sang artériel et veineux mixte prélevé pour analyse des gaz à des intervalles allant jusqu'à 24 h. Les poulains du groupe DBP ont reçu de la dexmédétomidine [2,4 ± 0,5 µg/kg de poids corporel (PC) par heure], du butorphanol (13 µg/kg de PC par heure) et du propofol (6,97 ± 0,86 mg/kg de PC par heure), tandis que les poulains du groupe MBP ont reçu du midazolam (0,14 ± 0,04 mg/kg de PC par heure), du butorphanol (13 µg/kg de PC par heure) et du propofol (5,98 ± 1,33 mg/kg de PC par heure). Les poulains du groupe DBP ont reçu significativement plus de bolus de propofol (9,0 ± 3,0) que ceux du groupe MBP (4,0 ± 2,0). Bien que les variables physiologiques soient restées dans des limites acceptables, la fréquence cardiaque (FC), la pression artérielle moyenne (MAP) et l'index cardiaque (IC) étaient plus faibles chez les poulains du groupe DBP que dans le groupe MBP. Les temps de décubitus sternal, de station debout et d'allaitement étaient significativement plus courts dans le groupe DBP que dans le groupe MBP. Nous avons constaté que les protocoles MBP et DBP sont adaptés pour assister l'assistance ventilatoire chez les poulains nouveau-nés, bien que le MBP entraîne une récupération prolongée par rapport au DBP.(Traduit par Docteur Serge Messier).

Disinfection of Maternal Environments Is Associated with Piglet Microbiome Composition from Birth to Weaning.

Maternal factors predetermine offspring development and health, including the establishment of offsprings' first microbiomes. Research in swine has shown that early microbial exposures impact microbiome colonization in piglets, but this phenomenon has never been tested in the context of delivery room disinfection. Thus, we exposed gestating sows to two delivery environments (n = 3/environment): stalls cleaned with a broad-spectrum disinfectant (disinfected environment [D]) or stalls cleaned only with hot-water power washing (nondisinfected environment [Nde]), 3 days prior to farrowing. Microbiomes of sows and farrowed piglets (n = 27/environment) were profiled at 4 different time points from birth to weaning via 16S rRNA sequencing. The results show that although vaginal, milk, skin, and gut microbiomes in mothers were minimally affected, sanitation of farrowing stalls impacted piglet microbiome colonization. These effects were mainly characterized by lower bacterial diversity in the gut and nasal cavity, specifically in D piglets at birth, and by distinct taxonomic compositions from birth to weaning depending on the farrowing environment. For instance, environmental bacteria greatly influenced microbiome colonization in Nde piglets, which also harbored significantly higher abundances of gut Lactobacillus and nasal Enhydrobacter at several time points through weaning. Different sanitation strategies at birth also resulted in distinct microbiome assembly patterns, with lower microbial exposures in D piglets being associated with limited interactions between bacterial taxa. However, increasing microbial exposures at birth through the lack of disinfection were also associated with lower piglet weight, highlighting the importance of understanding the trade-offs among optimal microbiome development, health, and growth performance in swine production systems. IMPORTANCE We show that levels of disinfection in farrowing facilities can impact early microbial exposures and colonization by pioneer microbes in piglets. Although previous research has shown a similar effect by raising pigs outdoors or by exposing them to soil, these practices are unattainable in most swine production systems in the United States due to biosecurity practices. Thus, our results underscore the importance of evaluating different disinfection practices in swine production to safely reduce pathogenic risks without limiting early microbial exposures. Allowing early exposure to both beneficial and pathogenic microbes may positively impact immune responses, reduce the stressors of weaning, and potentially reduce the need for dietary antimicrobials. However, the benefits of modified early microbial exposures need to be accomplished along with acceptable growth performance. Thus, our results also provide clues for understanding how disinfection practices in farrowing rooms may impact early microbiome development and assembly.

Mortality and ventilatory effects of central serotonin deficiency during postnatal development depend on age but not sex.

Serotonin (5-HT) influences brain development and has predominantly excitatory neuromodulatory effects on the neural respiratory control circuitry. Infants that succumb to sudden infant death syndrome (SIDS) have reduced brainstem 5-HT levels and Tryptophan hydroxylase 2 (Tph2). Furthermore, there are age- and sex-dependent risk factors associated with SIDS. Here we utilized our established Dark Agouti transgenic rat lacking central serotonin KO to test the hypotheses that CNS 5-HT deficiency leads to: (1) high mortality in a sex-independent manner, (2) age-dependent alterations in other CNS aminergic systems, and (3) age-dependent impairment of chemoreflexes during post-natal development. KO rat pups showed high neonatal mortality but not in a sex-dependent manner and did not show altered hypoxic or hypercapnic ventilatory chemoreflexes. However, KO rat pups had increased apnea-related metrics during a specific developmental age (P12-16), which were preceded by transient increases in dopaminergic system activity (P7-8). These results support and extend the concept that 5-HT per se is a critical factor in supporting respiratory control during post-natal development.

Maternal caffeine administration to ewes does not affect perinatal lamb survival.

Perinatal mortality of lambs is the major source of reproductive loss in extensive sheep production systems. Treatment with caffeine has reduced intra-partum mortality and/or improved metabolic indicators in other species following hypoxia. This study was conducted to evaluate the efficacy of caffeine for improving perinatal lamb survival. Experiment 1 comprised group-fed Merino ewes grazing pasture and offered 1.8 g/day (estimated 20 mg/kg live weight) caffeine throughout a 4-week lambing period, and a control without caffeine. The survival of lambs to marking (vaccinated, tail docked, males castrated) age in the caffeine treatment group (0.81) did not differ (P = 0.199) from that of control lambs (0.73; total born n = 877). Experiment 2 comprised Merino ewes lambing from three successive weekly joining groups. Treated ewes were drenched with an aqueous caffeine solution at a dose rate of 10 mg/kg live weight from the day before anticipated lambing, until the individual lambed. Control ewes were drenched with water. The proportion of lambs born dead (0.07) and the survival of lambs to marking age (caffeine 0.61; control 0.62) were similar between treatment groups (total born n = 1158). In both experiments, ewe mortality and the weight of lambs at marking were not altered by caffeine treatments. The results from this large-scale field study indicate caffeine is not an effective therapeutic agent to increase either intra-partum or perinatal survival, or lamb growth rates.

Skeletal muscle thermogenesis enables aquatic life in the smallest marine mammal.

Basal metabolic rate generally scales with body mass in mammals, and variation from predicted levels indicates adaptive metabolic remodeling. As a thermogenic adaptation for living in cool water, sea otters have a basal metabolic rate approximately three times that of the predicted rate; however, the tissue-level source of this hypermetabolism is unknown. Because skeletal muscle is a major determinant of whole-body metabolism, we characterized respiratory capacity and thermogenic leak in sea otter muscle. Compared with that of previously sampled mammals, thermogenic muscle leak capacity was elevated and could account for sea otter hypermetabolism. Muscle respiratory capacity was modestly elevated and reached adult levels in neonates. Premature metabolic development and high leak rate indicate that sea otter muscle metabolism is regulated by thermogenic demand and is the source of basal hypermetabolism.

Influence of environmental and anthropogenic acoustic cues in sea-finding of hatchling leatherback (Dermochelys coriacea) sea turtles.

Although the visual and geomagnetic orientation cues used by sea turtle hatchlings during sea-finding have been well studied, the potential for auditory stimuli to act as an orientation cue has not been explored. We investigated the response of sea turtle hatchlings to natural and anthropogenic noises present on their nesting beaches during sea-finding. The responses of hatchling leatherback sea turtles, Dermochelys coriacea, collected from the Sandy Point National Wildlife Refuge, St. Croix, were measured in the presence of aerial acoustic sounds within hatchlings' hearing range of 50 to 1600 Hz. The highest sound energy produced by beach waves occurs at frequencies 50-1000 Hz, which overlaps with the most sensitive hearing range of hatchling leatherbacks (50-400 Hz). Natural beach wave sounds, which have highest sound energy at frequencies of 50-1000 Hz, may be masked by human conversations (85-650 Hz) and vehicle traffic noise (60-8000 Hz). In the presence of three stimuli, a) beach wave sounds (72.0 dB re: 20 µPa), b) human conversation (72.4 dB re: 20 µPa), and c) vehicle traffic noise (71.1 dB re: 20 µPa), hatchlings exhibited no phonotaxic response (wave sounds: mean angle = 152.1°, p = 0.645; human conversation: mean angle = 67.4°, p = 0.554; traffic noise: mean angle = 125.7°, p = 0.887). These results may be due to the hatchlings being unable to localize sounds in the experimental arena. Visual and auditory cues may also converge to affect sea-finding orientation. Future studies should focus on the localization ability of sea turtles and on the role that sound may play in orientation when combined with other sensory and environmental cues.

Exposure to RF-EMF Alters Postsynaptic Structure and Hinders Neurite Outgrowth in Developing Hippocampal Neurons of Early Postnatal Mice.

Exposure to radiofrequency electromagnetic fields (RF-EMFs) has increased rapidly in children, but information on the effects of RF-EMF exposure to the central nervous system in children is limited. In this study, pups and dams were exposed to whole-body RF-EMF at 4.0 W/kg specific absorption rate (SAR) for 5 h per day for 4 weeks (from postnatal day (P) 1 to P28). The effects of RF-EMF exposure on neurons were evaluated by using both pups' hippocampus and primary cultured hippocampal neurons. The total number of dendritic spines showed statistically significant decreases in the dentate gyrus (DG) but was not altered in the cornu ammonis (CA1) in hippocampal neurons. In particular, the number of mushroom-type dendritic spines showed statistically significant decreases in the CA1 and DG. The expression of glutamate receptors was decreased in mushroom-type dendritic spines in the CA1 and DG of hippocampal neurons following RF-EMF exposure. The expression of brain-derived neurotrophic factor (BDNF) in the CA1 and DG was significantly lower statistically in RF-EMF-exposed mice. The number of post-synaptic density protein 95 (PSD95) puncta gradually increased over time but was significantly decreased statistically at days in vitro (DIV) 5, 7, and 9 following RF-EMF exposure. Decreased BDNF expression was restricted to the soma and was not observed in neurites of hippocampal neurons following RF-EMF exposure. The length of neurite outgrowth and number of branches showed statistically significant decreases, but no changes in the soma size of hippocampal neurons were observed. Further, the memory index showed statistically significant decreases in RF-EMF-exposed mice, suggesting that decreased synaptic density following RF-EMF exposure at early developmental stages may affect memory function. Collectively, these data suggest that hindered neuronal outgrowth following RF-EMF exposure may decrease overall synaptic density during early neurite development of hippocampal neurons.

Rodent studies of developmental programming and ageing mechanisms: Special issue: In utero and early life programming of ageing and disease.

Compelling evidence exists indicating that developmental programming influences ageing. Programming alters life-course phenotype in multiple organs, predisposing to diseases such as diabetes, obesity and cardiovascular disease that shorten lifespan. This review describes studies in rodents, the most commonly studied species, addressing interactions of programming challenges with ageing. We first consider ageing and programming of insulin function that has been clearly shown to decrease with age. It is important to evaluate ageing in pancreatic islets isolated from other systems. Studies discussed show premature pancreatic islet ageing resulting from both maternal under- and overnutrition. New ways to determine programming of adipose tissue and effects on fat storage are explored. Oxidative stress is a major factor that regulates ageing in tissues. Oxidative stress is discussed in relation to reproductive and cardiovascular ageing. Premature ageing is associated with both low and high glucocorticoid function. Both over and undernutrition have offspring sex-specific programming effects on life-course glucocorticoid concentrations. Evidence is provided that maternal age at conception affects offspring endocrine and metabolism ageing. Finally, the importance of matching foetal nutrition and energy availability with composition and energy content in the post-weaning diet is demonstrated. This mismatch can lead to a greatly shortened lifespan. General principles are discussed throughout. For example, sexual dimorphism of age-related outcomes can be marked. Accelerated ageing occurs early in life. Improving knowledge on programming ageing interactions will improve health span as well as lifespan. Finally, there are considerable similarities in outcomes programmed by maternal undernutrition and overnutrition.

A functional model of adult dentate gyrus neurogenesis.

In adult dentate gyrus neurogenesis, the link between maturation of newborn neurons and their function, such as behavioral pattern separation, has remained puzzling. By analyzing a theoretical model, we show that the switch from excitation to inhibition of the GABAergic input onto maturing newborn cells is crucial for their proper functional integration. When the GABAergic input is excitatory, cooperativity drives the growth of synapses such that newborn cells become sensitive to stimuli similar to those that activate mature cells. When GABAergic input switches to inhibitory, competition pushes the configuration of synapses onto newborn cells toward stimuli that are different from previously stored ones. This enables the maturing newborn cells to code for concepts that are novel, yet similar to familiar ones. Our theory of newborn cell maturation explains both how adult-born dentate granule cells integrate into the preexisting network and why they promote separation of similar but not distinct patterns.

Evaluation of the Effects of Developmental Trauma on Neurotransmitter Systems Using Functional Molecular Imaging.

Early life stress (ELS) is strongly associated with psychiatric disorders such as anxiety, depression, and schizophrenia in adulthood. To date, biological, behavioral, and structural aspects of ELS have been studied extensively, but their functional effects remain unclear. Here, we examined NeuroPET studies of dopaminergic, glutamatergic, and serotonergic systems in ELS animal models. Maternal separation and restraint stress were used to generate single or complex developmental trauma. Body weights of animals exposed to single trauma were similar to those of control animals; however, animals exposed to complex trauma exhibited loss of body weight when compared to controls. In behavioral tests, the complex developmental trauma group exhibited a decrease in time spent in the open arm of the elevated plus-maze and an increase in immobility time in the forced swim test when compared to control animals. In NeuroPET studies, the complex trauma group displayed a reduction in brain uptake values when compared to single trauma and control groups. Of neurotransmitter systems analyzed, the rate of decrease in brain uptake was the highest in the serotonergic group. Collectively, our results indicate that developmental trauma events induce behavioral deficits, including anxiety- and depressive-like phenotypes and dysfunction in neurotransmitter systems.

BREEDING AND NEONATAL REARING PRACTICES AND CHALLENGES IN LESSER HEDGEHOG TENRECS (ECHINOPS TELFAIRI) IN NORTH AMERICAN ZOOS.

The unique reproductive and energetic features of lesser hedgehog tenrecs (Echinops telfairi) have been intensively studied in the field and within laboratory settings, but information on their propagation in zoological settings is limited. Based on a survey sent to zoological institutions currently housing reproductively active lesser hedgehog tenrecs in North America, this study reports on husbandry, veterinary practices, and demographics of reproducing lesser hedgehog tenrecs and their offspring. All 14 zoological institutions in the Lesser Hedgehog Tenrec Species Survival Plan who bred tenrecs within the last 12 years responded to the online survey. Provision of a nest box, nesting material, and a diet consisting of a commercial insectivore diet, insects, and produce was found in the majority of institutions, in addition to the practice of separating the breeding male and female before parturition. From the 24 dams representing 39 pregnancies and 158 young included in this study, the median calculated litter size was four young per litter. The median age of primiparity was 2.25 yr, and the oldest female to reproduce successfully was 10 yr old. The young had an overall rate of survival to weaning of 83%. A maternal complication rate of 26% and maternal mortality rate of 5% highlights the importance of veterinary care in periparturient dams, especially for detection and treatment of dystocia. These data provide guidance to zoological institutions breeding lesser hedgehog tenrecs.

GLUT1 overexpression enhances glucose metabolism and promotes neonatal heart regeneration.

The mammalian heart switches its main metabolic substrate from glucose to fatty acids shortly after birth. This metabolic switch coincides with the loss of regenerative capacity in the heart. However, it is unknown whether glucose metabolism regulates heart regeneration. Here, we report that glucose metabolism is a determinant of regenerative capacity in the neonatal mammalian heart. Cardiac-specific overexpression of Glut1, the embryonic form of constitutively active glucose transporter, resulted in an increase in glucose uptake and concomitant accumulation of glycogen storage in postnatal heart. Upon cryoinjury, Glut1 transgenic hearts showed higher regenerative capacity with less fibrosis than non-transgenic control hearts. Interestingly, flow cytometry analysis revealed two distinct populations of ventricular cardiomyocytes: Tnnt2-high and Tnnt2-low cardiomyocytes, the latter of which showed significantly higher mitotic activity in response to high intracellular glucose in Glut1 transgenic hearts. Metabolic profiling shows that Glut1-transgenic hearts have a significant increase in the glucose metabolites including nucleotides upon injury. Inhibition of the nucleotide biosynthesis abrogated the regenerative advantage of high intra-cardiomyocyte glucose level, suggesting that the glucose enhances the cardiomyocyte regeneration through the supply of nucleotides. Our data suggest that the increase in glucose metabolism promotes cardiac regeneration in neonatal mouse heart.

Day-old chicken quality and performance of broiler chickens from 3 different hatching systems.

In on-farm hatching systems, eggs are transported at d 18 of incubation to the broiler farm, where chickens have immediate access to feed and water after hatching. In hatchery-fed systems, newly hatched chickens have immediate access to feed and water in the hatchery and are transported to the farm thereafter. Conventionally hatched chickens can remain without access to feed and water up to 72 h after hatching until placement on the farm. The current study compared day-old chicken quality, performance, and slaughter yield of broiler chickens that were on-farm hatched (OH), hatchery-fed (HF), or conventionally hatchery-hatched (HH). The experiment was performed in 6 rooms in 1 house. Each room contained 2 duplicate pens with approximately 1,155 chickens per pen; 2 rooms with each 2 duplicate pens were assigned to 1 treatment. The experiment was repeated during 3 consecutive production cycles. Chickens originated from young parent stock flocks. Results showed that HF and OH chickens were heavier and longer than HH chickens at day (D) 1. Relative weight of stomach and intestines were highest for OH chickens. The OH chickens had worse day-old chicken quality in terms of navel condition and red hocks than HH and HF chickens. Treatments did not differ in first wk and total mortality. From D0 until slaughter age, body weight was highest for OH, followed by HF and HH. Furthermore, carcass weight at slaughter age (D40) was highest for OH chickens, followed by HF and HH chickens. Breast fillets showed a higher incidence of white striping and wooden breast in HF and OH chickens compared with HH chickens. In conclusion, the current study showed that both OH and HF chickens of young parent flocks had better growth performance, which could explain the higher prevalence of breast myopathies, compared with HH. The worse day-old chicken quality for OH compared with HH and HF does not seem to affect first wk mortality and later life performance.