Genetic analysis of emotional reactivity in sheep: effects of the genotypes of the lambs and of their dams

A total of 1347 weaned lambs from eight genotypes were tested over five consecutive years: Romanov (ROM) and Lacaune (LAC) pure breeds, the two F1 crossbreeds (RL and LR) and the offspring of ewes from these four genotypes sired with Berrichon-du-Cher rams (BCF). The lambs were individually exposed to three challenging tests involving novelty, human contact and social isolation. Ten synthetic variables were used to express social reactivity (i.e., active vs. passive strategy), exploratory activity and reactivity to humans. BCF crossbreds were more active (i.e., high bleats, locomotion and attempts to escape) than purebreds and F1. In contrast, ROM expressed more passive responses (i.e., low bleats and vigilance postures) than LAC and BCF crossbreds. In addition, ROM approached a motionless human less and had longer flight distances to an approaching human than did LAC and BCF crossbreds. When restrained, ROM, and to a lesser extent B×ROM and B×LR, avoided human contact more than did LAC, RL and B×LAC. Most of these differences were explained by direct additive genetic effects while maternal influences or heterosis effects were rarely significant. The highest heritability was for high bleats (h² = 0.48). Females were more active and avoided human contact more than did males.     

Effect of subacute dietary nitrate on production traits and plasma analytes in Suffolk ewes

Elevated dietary nitrate (NO3-) is associated with production losses in ruminant livestock, resulting in substantial economic losses incurred by producers. Severe drought, fertilization practices and poorly maintained pastures increase the risk of elevated NO3- intake among cattle and sheep. Nitrate is metabolized to nitrite (NO2-) in the rumen and further reduced to ammonia. Ruminants consuming high dietary NO3- vary in ability to efficiently reduce excess NO2- to ammonia. This leads to methemoglobin formation and ultimately NO3- toxicity signs. Variation in individual tolerance to elevated dietary NO3- can be partially attributed to rate and duration of exposure, rate of elimination, metabolism, species and dose. Our objectives were to confirm and quantify variation in individual tolerance to subacute levels of dietary NO3-, and determine if individuals could be identified as highly or lowly tolerant to elevated dietary NO3- based on production traits, plasma analytes and(or) signs of subacute NO3- toxicity. Purebred Suffolk ewes were administered supplement mixed with tap water (control; n = 8) or potassium nitrate (NO3- treated; 300 mg NO3-/kg BW daily; n = 47) for 8 days. Coefficients of variation (CV) indicated that supplement intake was more variable in NO3- treated ewes (CV = 59.3%) than in control ewes (CV = 13.6%). Among NO3- treated ewes, six ewes highly tolerant and six ewes lowly tolerant to elevated dietary NO3- were identified based on individual performance, NO3- treated supplement intake, and signs of toxicity. Supplement intake was lower (P < 0.0001) in NO3- treated ewes than in control ewes, indicating elevated dietary NO3- influences feed intake. Supplement intake differed (P < 0.0001) between control, highly tolerant and lowly tolerant ewes. Supplement intake of highly and lowly tolerant ewes was 82% and 23%, respectively, of the control ewes' intake. Weight change and plasma concentrations of NO2-, cortisol, glucose and retinol were not different (P 0.38) among control, highly tolerant and lowly tolerant ewes. Plasma urea nitrogen (PUN) levels were not different (P = 0.25) between control and lowly tolerant ewes, but were lower (P = 0.02) in highly tolerant ewes than in control ewes. Furthermore, PUN and NO3- treated supplement intake were highly correlated (0.71; P < 0.0001) in lowly tolerant ewes. These results confirm and quantify variation in response to subacute levels of dietary NO3- and indicate that individuals can be identified as highly or lowly tolerant to elevated dietary NO3- based on their performance and NO3- toxicity signs.     

Evidence that endogenous thyrotropin-releasing hormone (TRH) may control vagal efferents to thyroid gland: neural inhibition by central administration of TRH antiserum

The intracerebroventricular (i.c.v.) injection of rabbit antiserum to thyrotropin-releasing hormone (TRH) to the urethane anesthetized rat inhibited the spontaneous electrical discharge of the superior laryngeal nerve (n.sl). On the other hand, the i.c.v. injection of rabbit antiserum to somatostatin (SRIF) failed to influence the nerve activity whereas SRIF itself is capable of inhibiting the n.sl activity. These findings suggest that TRH in the brain takes a role continuously in regulating the neural activity while SRIF is involved in the neuronal circuits as an agent for the down regulation of the autonomic nervous system.     

Subjective assessment of reactivity level and personality traits of rhesus monkeys

The purposes of this study are to determine whether subjective assessment of reactivity level in rhesus macaques, between 1 and 14 years old, is related to assessment of personality traits and whether a configuration of personality traits most salient for assessment of reactivity can be defined. Results indicate that subjective assessment of reactivity is complementary to that of personality traits. Interrater reliability and convergent validity are established. Principal-component and discriminant analyses of the present data show that 10 personality traits can assign all' subjects to reactivity level, but as few as 3 traits may be sufficient.     

Effect of plane of nutrition of 1- and 2-year-old ewes in early and mid-pregnancy on ewe reproduction and offspring performance up to weaning

The objective of the present study was to determine the effect of plane of nutrition in early pregnancy (EP) and mid-pregnancy (MP), on the productive performance of 1- and 2-year-old ewes and their offspring. Over 2 successive years, between days 0 and 39 after synchronized mating (EP), 1- (n = 117) and 2- (n = 52) year-old ewes were allowed 60% (low, L-EP), 100% (medium, M-EP) or 200% (high, H-EP) of requirements for maintenance (M). Between days 40 and 90 (MP), 1-year-old ewes were allowed 140% (M-MP) or 200% (H-MP), while 2-year-old ewes were allowed 80% (M-MP) or 140% (H-MP) of their M requirement. After day 90, all ewes were fed to meet requirements for late pregnancy. Increasing the plane of nutrition between days 0 and 39 resulted in increases in live weight (LW) (P < 0.001) and body condition score (BCS) (P < 0.001) during the EP period (H-EP > M-EP > L-EP), differences that in 1-year-old ewes were sustained to lambing (P < 0.05). On day 42 of gestation H-EP ewes had lower plasma progesterone concentrations than L-EP or M-EP ewes in 1- (P < 0.01) and 2- (P < 0.001) year olds. This was concomitant with diet H-EP tending to reduce the number of lambs born per ewe in both age groups (P = 0.06 and 0.07, respectively). Foetuses from 1-year-old L-EP ewes had smaller cranial (P < 0.01) and abdominal (P < 0.05) diameters at day 53 of gestation, with H-EP lambs tending to be heaviest at birth (P = 0.07). Similar findings were recorded for 2-year-old ewes. One-year-old ewes offered diet L-EP presented negative maternal behaviours more frequently (P < 0.05), while the incidence of lamb mortality at 6 weeks tended to be greater for L-EP lambs (P = 0.07). In MP, 1-year-old ewes offered diet M-MP were associated with foetuses with bigger abdominal diameters at day 78 (P < 0.05). However, there were no differences in lamb weight or size at term (P > 0.05). These ewes exhibited more positive maternal behaviours (e.g. increased grooming frequency and duration; P < 0.05) than ewes offered diet H-MP, and their offspring were more successful in suckling (P < 0.05). Results suggest that in young ewes, a temporary nutrient restriction in EP resulted in increased prolificacy. However, ewes and their offspring were lighter at birth and ewe maternal behaviour was poorer, resulting in increased lamb mortality. In MP, a medium plane of nutrition offered to 1-year-old ewes led to improved maternal and offspring behaviour.     

Age-related changes in the innervation of the prostate gland

The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.     

Nutritional status of adult ewes during early and mid-pregnancy. 1. Effects of plane of nutrition on ewe reproduction and offspring performance to weaning

The objective of this study was to determine the effects of plane of nutrition during early and mid-pregnancy on the performance of mature ewes and their offspring. From day 0 to day 39 post mating (early pregnancy, EP), 82 multiparous ewes were fed to provide either 60% (low, L), 100% (medium, M) or 200% (high, H) of predicted metabolisable energy (ME) requirements for maintenance, following a synchronised mating. From day 40 to day 90 (mid-pregnancy, MP), ewes were provided with either 80% (M) or 140% (H) of ME requirements. After 90 days of gestation, all ewes were fed to meet requirements for late pregnancy. During EP, mean live weight (LW) and body condition score (BCS) change of ewes were -6.3, -0.8 and +6.0 kg and -0.02, +0.10 and +0.22 units in the L-, M- and H-EP treatments, respectively. During MP, mean LW and BCS change were -0.8 and +4.9 kg and -0.09 and +0.09 units in the M- and H-MP treatments, respectively (P < 0.001). Treatments had no effect (P > 0.05) on conception rate, although there tended to be an inverse relationship (P = 0.085) between plane of nutrition in EP and plasma progesterone concentrations at day 42 of gestation. EP nutrition influenced foetal development with lambs from ewes offered diet L-EP being smaller (P < 0.01) at day 56 than M- or H-EP lambs. However, at parturition L-EP lambs were heavier (P < 0.05) and tended to have higher (P = 0.056) immunoglobulin status 24 h after birth. Mortality rates at weaning were reduced (P < 0.05) for lambs born from ewes offered diet L-EP compared with M- or H-EP lambs. Diet M during mid-pregnancy resulted in larger (P < 0.05) foetuses at day 80 of gestation. At parturition, these lambs had longer head and crown-rump lengths than H-MP lambs (P < 0.05). Lambs born to ewes offered diet M-MP tended to progress faster to attempting to suckle than H-MP lambs (P = 0.089). There was an interaction between plane of nutrition in early and mid-pregnancy, whereby the highest number of lambs weaned was a result of diet L-EP followed by diet M-MP. These results indicate that in adult ewes, temporary nutrient restriction during early pregnancy results in better lamb survival; and mild nutrient restriction in mid-pregnancy tends to improve neonatal behaviour and results in lambs with longer skeletal size.     

Development of the swimbladder and its innervation in the zebrafish, Danio rerio

Many teleosts including zebrafish, Danio rerio, actively regulate buoyancy with a gas-filled swimbladder, the volume of which is controlled by autonomic reflexes acting on vascular, muscular, and secretory effectors. In this study, we investigated the morphological development of the zebrafish swimbladder together with its effectors and innervation. The swimbladder first formed as a single chamber, which inflated at 1-3 days posthatching (dph), 3.5-4 mm body length. Lateral nerves were already present as demonstrated by the antibody zn-12, and blood vessels had formed in parallel on the cranial aspect to supply blood to anastomotic capillary loops as demonstrated by Tie-2 antibody staining. Neuropeptide Y-(NPY-) like immunoreactive (LIR) fibers appeared early in the single-chambered stage, and vasoactive intestinal polypeptide (VIP)-LIR fibers and cell bodies developed by 10 dph (5 mm). By 18 dph (6 mm), the anterior chamber formed by evagination from the cranial end of the original chamber; both chambers then enlarged with the ductus communicans forming a constriction between them. The parallel blood vessels developed into an arteriovenous rete on the cranial aspect of the posterior chamber and this region was innervated by zn-12-reactive fibers. Tyrosine hydroxylase- (TH-), NPY-, and VIP-LIR fibers also innervated this area and the lateral posterior chamber. Innervation of the early anterior chamber was also demonstrated by VIP-LIR fibers. By 25-30 dph (8-9 mm), a band of smooth muscle formed in the lateral wall of the posterior chamber. Although gas in the swimbladder increased buoyancy of young larvae just after first inflation, our results suggest that active control of the swimbladder may not occur until after the formation of the two chambers and subsequent development and maturation of vasculature, musculature and innervation of these structures at about 28-30 dph.     

Nutritional status of adult ewes during early and mid-pregnancy. 2. Effects of supplementation with selenised yeast on ewe reproduction and offspring performance to weaning

The objective of this study was to determine the effects of selenium (Se) supplementation of mature ewes in the period from day −14 to day 90 post mating on Se status, productivity and viability of ewes and their offspring. Multiparous crossbred ewes (n = 82) were randomly assigned to receive a standard dried grass-based diet (control) or dried grass diet supplemented with 1 g of selenised yeast (Selplex®), providing 0.5 mg Se per ewe per day. After day 90 post mating, all ewes were offered grass-based diets supplemented with a standard multivitamin and mineral mix, up to lambing. Ewes that were fed additional Se had increased (P < 0.001) activity of glutathione peroxidase enzyme (GPx) and increased plasma Se concentrations throughout the treatment period. At lambing, GPx activity of supplemented ewes was higher (P < 0.001) than that of controls. Twenty-four hours after birth, lambs of ewes given Se had higher (P < 0.001) concentration of Se in plasma, greater (P < 0.001) activity of GPx and better (P < 0.01) immune status. Lambs of ewes that received supplementation showed a faster progression to stand than control lambs (P < 0.05), independent of maternal behaviour which was not affected. Supplementation reduced perinatal lamb mortality (0.04 v. 0.17; P < 0.05). However, overall mortality from birth to weaning was unaffected (P > 0.05). Supplemented ewes weaned lambs on average 2 kg heavier than control ewes, due to the higher (P < 0.05) growth rates achieved by their offspring. In conclusion, for ewes with a marginal Se status, an organic source of Se supplemented throughout pregnancy, compared with supplementation only in the last trimester, positively affected measures of lamb viability and survival.     

The placebo effect and the autonomic nervous system: evidence for an intimate relationship

For many subjectively experienced outcomes, such as pain and depression, rather large placebo effects have been reported. However, there is increasing evidence that placebo interventions also affect end-organ functions regulated by the autonomic nervous system (ANS). After discussing three psychological models for autonomic placebo effects, this article provides an anatomical framework of the autonomic system and then critically reviews the relevant placebo studies in the field, thereby focusing on gastrointestinal, cardiovascular and pulmonary functions. The findings indicate that several autonomic organ functions can indeed be altered by verbal suggestions delivered during placebo and nocebo interventions. In addition, three experimental studies provide evidence for organ-specific effects, in agreement with the current knowledge on the central control of the ANS. It is suggested that the placebo effects on autonomic organ functions are best explained by the model of 'implicit affordance', which assumes that placebo effects are dependent on 'lived experience' rather than on the conscious representation of expected outcomes. Nevertheless, more studies will be needed to further elucidate psychological and neurobiological pathways involved in autonomic placebo effects.     

Adaptive evolution of a key gene affecting queen and worker traits in the honey bee, Apis mellifera

The vitellogenin egg yolk precursor protein represents a well-studied case of social pleiotropy in the model organism Apis mellifera. Vitellogenin is associated with fecundity in queens and plays a major role in controlling division of labour in workers, thereby affecting both individual and colony-level fitness. We studied the molecular evolution of vitellogenin and seven other genes sequenced in a large population panel of Apis mellifera and several closely related species to investigate the role of social pleiotropy on adaptive protein evolution. We found a significant excess of nonsynonymous fixed differences between A. mellifera, A. cerana and A. florea relative to synonymous sites indicating high rates of adaptive evolution at vitellogenin. Indeed, 88% of amino acid changes were fixed by selection in some portions of the gene. Further, vitellogenin exhibited hallmark signatures of selective sweeps in A. mellifera, including a significant skew in the allele frequency spectrum, extreme levels of genetic differentiation and linkage disequilibrium. Finally, replacement polymorphisms in vitellogenin were significantly enriched in parts of the protein involved in binding lipid, establishing a link between the gene's structure, function and effects on fitness. Our case study provides unequivocal evidence of historical and ongoing bouts of adaptive evolution acting on a key socially pleiotropic gene in the honey bee.     

Promoting positive states: the effect of early human handling on play and exploratory behaviour in pigs

It is known that tactile stimulation (TS) during ontogeny modifies brain plasticity and enhances the motor and cognitive skills. Our hypothesis was that early handling including TS would increase play and exploratory behaviour in commercial pigs under standardized test conditions. Piglets from 13 litters were subjected to three handling treatments from 5 to 35 days of age: all the piglets were handled (H), none of the piglets were handled (NH) or half of the piglets in the litter were handled (50/50). At 42 days of age, the pigs’ behaviour was observed in pairs in a novel pen with a ‘toy’ (tug rope). The main results were that more locomotor play was performed by pigs from litters where all or half of them had been handled, whereas social exploratory behaviour was more pronounced in pigs from litters where half of them had been handled. Although behaviour was affected by the interaction of treatment with sex or with weight category, we propose that the handling procedure does seem to have acted to increase locomotor skills and that handling half of the piglets in the litter may have triggered a series of socio-emotional interactions that were beneficial for the whole group.     

Physiological and Neurochemical Aspects of Corticotropin-Releasing Factor Actions in the Brain: The Role of the Locus Coeruleus

Corticotropin-releasing factor (CRF) is both a major regulator of the hypothalamo-pituitary-adrenal (HPA) axis and the activity of the autonomic nervous system. Besides, it exerts numerous effects on other physiological functions such as appetite control, motor and cognitive behavior and immune function. The basis for these effects is constituted by its distribution in hypothalamic and extrahypothalamic brain areas, the latter being represented by limbic structures such as the central nucleus of the amygdala or by brain stem neurons such as the locus coeruleus (LC) or nucleus of the solitary tract (NTS). The effects of CRF are mediated through recently described CRF-receptor subtypes, whose molecular biology, biochemistry and pharmacological regulation are discussed in detail. In the second part of this review, we will focus on the physiology of CRF-systems in the brain, with a particular emphasis on cardiovascular regulation, respiration, appetite control and stress-related behavior. Finally, the role of the locus coeruleus in the control of CRF-mediated behavioral activities is discussed. The interaction of noradrenergic and CRF-neurons clearly implies that CRF appears to directly activate LC neurons in a stressful situation, thus ultimately coordinating the bodily response to a stressful stimulus.     

A comparison of the periparturient rise in fecal egg counts of exotic and domestic ewes

Ewes of three exotic breeds (Florida Native, Barbados Blackbelly and St. Croix) showed no periparturient rise in fecal egg counts (PPR) when housed from late fall through lambing and weaning. Domestic breed ewes (Rambouillet and Finn-Dorset × Rambouillet) showed a pronounced PPR 6–7 weeks post-lambing while St. Croix × domestic ewes showed an intermediate PPR under similar conditions. There was no PPR in non-lambing ewes.In a second experiment, breed differences in the PPR were not as pronounced when ewes were allowed to graze a contaminated pasture after lambing. Florida Native, St. Croix and $\text{3}\text{4}$ St. Croix × $\text{1}\text{4}$ domestic showed lower PPRs than the remaining breeds (Barbados Blackbelly, F₁ hybrids of exotic and domestic breeds and domestic ewes), but the magnitude of the PPR was generally small in all breeds. No relationship was observed between hemoglobin genotype and PPR in either experiment.It was concluded that a low or absent PPR is an important manifestation of breed resistance in exotic ewes and that this may be useful as a marker for breeding parasite-resistant sheep.     

Circadian expression of connexins in the mouse heart

Significant circadian variations exist in the frequency of cardiac arrhythmia; however, the underlying mechanism is largely unknown. Connexins are essential in the propagation of electrical activity throughout the heart and are an important determinant of conduction velocity. Their dysfunction is related to the genesis of cardiac arrhythmia. In this study, we investigated if cx40 and cx43 expressed circadianly in the mouse heart using suprachiasmatic nuclei (SCN) lesion and pharmacological autonomic nervous system block mouse. Significant 24-h variations were observed in the expression of cx40 and cx43 in the sham-operated mice. In the SCNX mouse, all genes examined lost circadian rhythm. In the ANSB mouse, the expressions of Bmal1 was dampened significantly but still had circadian rhythm, whereas the two connexin gene expressions lost rhythm. These results suggest that cx40 and cx43 gene expressions have clear circadian rhythm and might be regulated by the central clock in the SCN through the ANS.     

Autonomic denervation for the treatment of atrial fibrillation

The influence of the autonomic nervous system (ANS) on triggering and perpetuation of atrial fibrillation (AF) is well established. Ganglionated plexi (GP) ablation achieves autonomic denervation by affecting both the parasympathetic and sympathetic components of the ANS. An anatomic approach for GP ablation at relevant atrial sites appears to be safe, and improves the results of PV isolation in patients with paroxysmal and persistent AF. GP ablation can be accomplished endocardially or epicardially, ie, during the maze procedure or thoracoscopic approaches. Further experience is needed to assess the clinical value of this promising technique.     

Effects of age and streptozotocin-induced diabetes on biogenic amines in rat tail artery

The changes in amine concentrations in different segments of the rat tail artery have been investigated at different ages and after different durations of streptozotocin-induced diabetes. There was a significant positive slope to the relationship between amine concentrations and age in proximal portion of the normal tail artery, and a significant additional increase in amine concentrations following induction of diabetes. The peak of the latter response occurred between 10 and 20 weeks following the induction of diabetes. There was also a significant dependence on the length of the post-ganglionic neurones, which may be related to the failure of axonal transport of some of the essential enzymes or transporters for these biogenic amines. This model of altered catecholamine metabolism and handling requires further investigation so that alterations in the mechanisms involved in processing of these amines in diabetic autonomic neuropathy may be elucidated. (Mol Cell Biochem 261: 77–82, 2004)