Armin Tuchscherer

Early identification of neonates at risk: traits of newborn piglets with respect to survival.

Despite technological changes and improved management, piglet mortality remains a problem for both production and welfare. Most preweaning mortality occurs within the first 3 days after birth because of problems with adaptation and development. Thus, the purpose of our study was to determine the physiologic state of newborn pigs with respect to piglet survival. Data were collected from 1024 live-born piglets of 106 primiparous German Landrace sows to analyze relationships between farrowing traits, early postnatal vitality and blood chemistry, including immunity of piglets at birth. Surviving piglets were compared with those that died during the first 10 days of life. The survivors were significantly heavier at birth (P=0.001), were born earlier in the birth order (P=0.04), reached the udder and took in first colostral milk more quickly (P=0.001) and had a smaller drop in rectal temperature I h after birth (P=0.001) than dead. However, dead piglets had significantly higher blood levels of inorganic phosphorus (P=0.0001), calcium (P=0.04) and urea (P=0.05), but a lower concentration of alpha2-macroglobulin and lower lymphocyte proliferation indices in response to pokeweed mitogen (P=0.05). Models fitted for discrimination between survivors and piglets that died included, in addition to birth weight and litter size, the foraging behavior of neonates (time from birth to first suckle) and their thermoregulatory capacity (rectal temperature 1 h after birth) in the first experimental unit, as well as prenursing biochemical measures (inorganic phosphorus, calcium and glucose) in the second experimental unit. These ethophysiological and biochemical traits of early postnatal vitality are important determinants of maturity and development at birth. Hence, breeding programs and perinatal housing and feeding conditions should ensure a high physiological maturity to improve mortality rates of neonates.

Consequences of repeated early isolation in domestic piglets (Sus scrofa) on their behavioural, neuroendocrine, and immunological responses.

Stress in the form of intermittent maternal deprivation and social isolation during early postnatal life in rats and monkeys produces persistent changes in physiology and behaviour. In farm animals physiological consequences of disrupting mother-infant interactions with respect to health and animal welfare are relatively unknown. Therefore, the aim of the present study was to investigate the behavioural, neuroendocrine and immunological consequences of a 2 h daily social isolation from day 3 to day 11 of age in domestic piglets as well as potential long-term effects on the brain-endocrine-immune regulation. Repeated social isolation resulted in significantly decreased open-field activity (locomotion, vocalization) during the isolation period, increased basal cortisol concentrations and decreased lymphocyte proliferation in response to concanavalin A and pokeweed mitogen one day after the isolation. There was also a significant increase of interleukin-1beta (IL-1beta) concentration in hippocampus in isolated piglets compared to controls at this time. Six weeks after isolation significant enhanced basal ACTH concentrations as well as higher IL-1beta content and glucocorticoid receptor (GR) binding in hippocampus were found. These endocrine and immune responses were associated with decreased CRH levels in the hypothalamus and increased CRH content in the amygdala. The present data indicate that early social isolation in pigs may cause changes in behavioural, neuroendocrine, and immune regulation and produce long-term effects not only on the activity of the hypothalamic-pituitary-adrenal (HPA) system, but also on the immune-brain circuitry with possible negative consequences in health and welfare of commercial pigs. Using the pig as a suitable animal model, the finding of this study may also have some implications for the etiology of anxiety and depression in humans.

Effects of social status after mixing on immune, metabolic, and endocrine responses in pigs

The effects of social rank on immune, metabolic, and endocrine responses were studied in 10 newly mixed groups of German Landrace pigs (9 individuals each) at an age of 12 weeks. Immediately after mixing, the agonistic interactions (AI) of all group members were continuously recorded over 3 days (10 h daily). An individual dominance value (DV) was calculated by the number of wins minus defeats in relation to all decisive fights (DV < or = 0, subordinate; DV > 0, dominant). Blood samples were taken 24 h before and 3 days after mixing. The data showed that the social status had a significant effect on lymphocyte proliferation in responses to different mitogens: socially dominant pigs had higher proliferative response than subordinate pigs. In addition, during the observation period the lymphocyte activation by mitogens increased in the dominant animals and decreased in the subordinate animals with increasing number of agonistic interactions. The rise in total serum IgG concentration 3 days after mixing was higher in dominant pigs compared with subordinates. The dominance status did not significantly affect plasma metabolic levels nor cortisol concentrations. However, mixing appeared to increase glucose and total protein values and to decrease alkaline phosphatase and cortisol levels in both, dominant and subordinate pigs. In conclusion, mitogen induced cell proliferation seems to be a valuable marker for acute social stress in pigs.

Variation in fat mobilization during early lactation differently affects feed intake, body condition, and lipid and glucose metabolism in high-yielding dairy cows

Fat mobilization to meet energy requirements during early lactation is inevitable because of insufficient feed intake, but differs greatly among high-yielding dairy cows. Therefore, we studied milk production, feed intake, and body condition as well as metabolic and endocrine changes in high-yielding dairy cows to identify variable strategies in metabolic and endocrine adaptation to overcome postpartum metabolic load attributable to milk production. Cows used in this study varied in fat mobilization around calving, as classified by mean total liver fat concentrations (LFC) postpartum. German Holstein cows (n=27) were studied from dry off until d 63 postpartum in their third lactation. All cows were fed the same total mixed rations ad libitum during the dry period and lactation. Plasma concentrations of metabolites and hormones were measured in blood samples taken at d 56, 28, 15, and 5 before expected calving and at d 1 and once weekly up to d 63 postpartum. Liver biopsies were taken on d 56 and 15 before calving, and on d 1, 14, 28, and 49 postpartum to measure LFC and glycogen concentrations. Cows were grouped accordingly to mean total LFC on d 1, 14, and 28 in high, medium, and low fat-mobilizing cows. Mean LFC (±SEM) differed among groups and were 351±14, 250±10, and 159±9 mg/g of dry matter for high, medium, and low fat-mobilizing cows, respectively, whereas hepatic glycogen concentrations postpartum were the highest in low fat-mobilizing cows. Cows in the low group showed the highest dry matter intake and the least negative energy balance postpartum, but energy-corrected milk yield was similar among groups. The decrease in body weight postpartum was greatest in high fat-mobilizing cows, but the decrease in backfat thickness was greatest in medium fat-mobilizing cows. Plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate were highest around calving in high fat-mobilizing cows. Plasma triglycerides were highest in the medium group and plasma cholesterol concentrations were lowest in the high group at calving. During early lactation, the decrease in plasma glucose concentrations was greatest in the high group, and plasma insulin concentrations postpartum were highest in the low group. The revised quantitative insulin sensitivity check index values decreased during the transition period and postpartum, and were highest in the medium group. Plasma cortisol concentrations during the transition period and postpartum period and plasma leptin concentrations were highest in the medium group. In conclusion, cows adapted differently to the metabolic load and used variable strategies for homeorhetic regulation of milk production. Differences in fat mobilization were part of these strategies and contributed to the individual adaptation of energy metabolism to milk production.

Effects of postnatal social isolation on hormonal and immune responses of pigs to an acute endotoxin challenge

Social stress during early postnatal life often results in long-term effects on neuroendocrine and immune adaptation mechanisms. Therefore, the aim of the present study was to determine the influence of a 2-h daily social isolation from Day 3 to Day 11 on the acute and long-term proinflammatory and neuroendocrine responses of piglets challenged with the bacterial endotoxin lipopolysaccharide (LPS; 100 microg/kg body weight). Peripheral LPS administration significantly increased plasma concentrations of tumor necrosis factor-alpha (TNF-alpha), ACTH and cortisol in isolated and control pigs. However, the activity of the hypothalamic-pituitary-adrenal (HPA) axis after LPS stimulation was not significantly affected by isolation treatment, whereas the prior social isolation diminished the plasma TNF-alpha response to LPS 1 day as well as 45 days after the isolation period. The hippocampal TNF-alpha concentration in response to LPS was also reduced in priorly isolated pigs compared to control animals. Furthermore, the significant increase of TNF-alpha in the spleen caused by LPS was associated with a dramatic decrease in glucocorticoid receptor (GR) binding. The GR binding in hippocampus was increased in isolated pigs and was significantly decreased after LPS injection. In addition, the repeated isolation stressor was shown to increase hippocampal levels of interleukin-1beta (IL-1beta). The present results indicate that repeated social isolation of neonatal pigs may cause long-term effects on proinflammatory regulation at the periphery and in the brain following immune challenge with particular importance of TNF-alpha in mediating these interactions.

Neuroendocrine and Immune Responses to Acute Endotoxemia in Suckling and Weaned Piglets

The objective of this study was to characterize effects of weaning stress on behavioural, endocrine and immune responses to acute peripheral lipopolysaccharide (LPS) challenge in neonatal pigs. Weaning in 28-day-old piglets was accompanied by a significant increase in ACTH concentrations (p = 0.0378) and an increase in basal cortisol level (p = 0.0135). There was also a significant suppressive effect on lymphocyte proliferation in response to concanavalin A (p = 0.0048) in newly weaned piglets. Peripheral administration of LPS induced vomiting, diarrhoea and somnolence in both suckling and weaned piglets. The frequency of these signs of sickness was significantly higher in weaned piglets compared with suckling piglets (p = 0.0049). Additionally, LPS significantly increased plasma concentrations of TNF-α, cortisol and ACTH. While weaned piglets reacted to LPS with a higher release of ACTH (p = 0.0239) and cortisol (p = 0.0015) than suckling piglets there was no significant effect of weaning on the magnitude of TNF-α. The present data indicate that weaning suppresses the lymphocyte function, causes changes in endocrine regulation and has a substantial effect on the behavioural and endocrine response to an acute peripheral LPS challenge; consequently it could increase disease susceptibility.

A single exposure to social isolation in domestic piglets activates behavioural arousal, neuroendocrine stress hormones, and stress-related gene expression in the brain

Stressful early life events can have short- and long-term effects on neuroendocrine and behavioural mechanisms of adaptation. Here, we investigated the effects of a single social isolation (4 h) of domestic piglets on both behavioural alterations in open-field tests and modifications in the expression of genes regulating glucocorticoid response in stress-related brain regions at 7, 21 or 35 days of age. The mRNAs of glucocorticoid receptor (GR), mineralocorticoid receptor (MR), 11ss-hydroxysteroid dehydrogenase 1 and 2 (11ss-HSD1 and 11ss-HSD2) and c-fos were analysed by real-time RT-PCR in the hypothalamus, hippocampus and amygdala. The social isolation caused both elevated stress hormone concentrations (e.g. cortisol) and open-field reactivity (e.g. locomotion, vocalisation) compared to control piglets. The enhanced behavioural and neuroendocrine activity was associated with distinct changes in gene expression in the limbic system. The hypothalamic GR, MR and 11ss-HSD1 mRNA expressions and the hippocampal 11ss-HSD1 mRNA was significantly higher in isolated piglets, whereas in the amygdala social isolation caused a significant decrease in MR mRNA expression. Isolated piglets also displayed significantly higher c-fos mRNA expression, an estimate of neuronal activation, in hypothalamus and amygdala. The mRNA alterations as well as the behavioural and hormonal pattern show an effect of social isolation on days 7 and 21, but no effect on day 35. In conclusion, a single social isolation in piglets caused age-dependent neuroendocrine and behavioural changes that indicate increased arousal and experienced distress. The present results also suggest that psychosocial stress effects should be considered for the assessment of livestock handling practices with respect to health and welfare.

Early social isolation alters behavioral and physiological responses to an endotoxin challenge in piglets

Psychosocial stress in the form of maternal deprivation and social isolation during early postnatal life induces persistent alterations in behavioral and physiological mechanisms of adaptation. One consequence may be an increased susceptibility to diseases in later life. Therefore, the aim of the present study was to investigate in domestic piglets the effects of a repeated social isolation (2 h daily from day 3 to day 11 of age) on behavioral, endocrine and immune responses to an endotoxin challenge with lipopolysaccharide (LPS) 1 day or 45 days after the isolation period. Peripheral LPS administration caused serious sickness behavior (somnolence, shivering, vomiting) and provoked profound increases in circulating tumor necrosis factor-alpha (TNF-alpha), ACTH and cortisol concentrations. The prior social isolation treatment enhanced signs of sickness and impaired suckling behavior. Early isolated piglets responded to LPS by an increase of shivering on day 12 and by increased vomiting on day 56 compared to controls. Further, there were considerable delays and reductions of time isolated piglets spent suckling on day 12. The repeated isolation stressor diminished TNF-alpha increases after LPS, whereas stress hormone levels were not significantly affected by isolation treatment. Finally, stronger relationships between signs of sickness and physiological measures were revealed in early isolated piglets. The duration of somnolence in isolated piglets was related to changes of cortisol and TNF-alpha concentrations, and the highest impact on duration of shivering was found for changes in cortisol and corticosteroid binding globulin levels. The present results suggest a sustained adaptive sensitization of coping with infection by social stress experience during early development in piglets.

Changes in cumulus-oocyte complexes of pregnant and non-pregnant camels (Camelus dromedarius) during maturation in vitro.

The aim of the present study was to examine the cumulus morphology and the oocyte chromatin quality of camel cumulus-oocyte complexes (COCs) at the time of recovery, and to monitor changes in oocyte chromatin configuration and apoptosis in cumulus cells from camel COCs during in vitro maturation (IVM) (0, 12, 24, 32, 36, 42, and 48 p.IVM) depending on pregnancy of donors. A total of 1023 COCs were isolated from sliced ovaries after slaughtering of 47 pregnant and 43 non-pregnant camels in an abattoir. The mean number of COCs per donor was 10.3 in pregnant and 12.5 in non-pregnant donors. The cumulus morphology of COCs was independent of the type of donor and was divided in COCs with compact (26.9 and 28%), dispersed (39.3 and 46%), corona radiata cumulus investment (27.9 and 21.7%) and without cumulus (6 and 4.2%), respectively for pregnant and non-pregnant donors. The highest proportion of COCs exhibited dispersed cumulus (P<0.05). Oocytes with meiotic stages of diplotene >50% were found only in compact (55 and 56.5%) and in dispersed COCs (58.4 and 60%), respectively for pregnant and non-pregnant donors. During IVM (0-48h) the first significant onset of specific meiotic stages were different in oocytes from pregnant donors: metaphase 1 (24-32h), metaphase 2 (36-42h), versus oocytes from non-pregnant donors: metaphase 1 (24h), metaphase 2 (32-48h) (P<0.05). The level of apoptotic cells in cumuli of matured COCs increased during IVM and was higher in matured COCs from non-pregnant donors for each time point during IVM (P<0.01). Camel oocytes meiosis during IVM is accompanied by a drastic increase of apoptosis in the surrounding cumulus cells 0-32 and 0-24h during IVM, respectively for pregnant and non-pregnant donors. The oocytes of pregnant camels require 36h of maturation to reach levels of >50% metaphase 2 stage in comparison to oocytes from non-pregnant donors where 32h are sufficient. The earlier onset of apoptosis in the COCs derived from non-pregnant donors possibly determines the faster progression of the oocytes through the final stages of meiosis.

Changes in endocrine and immune responses of neonatal pigs exposed to a psychosocial stressor.

The aim of the study was to determine the effects of a single social isolation (4h) of piglets on immediate changes in stress hormones and immune responses at 7, 21 or 35 days of age. This social stressor caused an increase in plasma ACTH and cortisol concentrations and a decrease in plasma TNF-alpha. The percentage of CD8+ cells increased and the CD4+ cell percentage decreased, resulting in decreasing CD4+/CD8+ ratio. The observed changes were consistent for all days studied. Further, the isolation treatment resulted in diminished LPS-stimulated IL-1beta and IL-10 production in whole-blood cultures. In isolated piglets, positive correlations were estimated between changes in percentage of CD8+ cells and cortisol, and negative ones between changes in plasma TNF-alpha and culture supernatant IL-1beta with ACTH and cortisol. The data suggest that psychosocial stress in neonatal pigs induced immune alterations to maintain adaptive stability, but reflecting also negative emotions experienced by this treatment.