Cortisol levels are positively associated with pup-feeding rates in male meerkats

In societies of cooperative vertebrates, individual differences in contributions to offspring care are commonly substantial. Recent attempts to explain the causes of this variation have focused on correlations between contributions to care and the protein hormone prolactin, or the steroid hormone testosterone. However, such studies have seldom considered the importance of other hormones or controlled for non-hormonal factors that are correlative with both individual hormone levels and contributions to care. Using multivariate statistics, we show that hormone levels explain significant variation in contributions to pup-feeding by male meerkats, even after controlling for non-hormonal effects. However, long-term contributions to pup provisioning were significantly and positively correlated with plasma levels of cortisol rather than prolactin, while plasma levels of testosterone were not related to individual patterns of pup-feeding. Furthermore, a playback experiment that used pup begging calls to increase the feeding rates of male helpers gave rise to parallel increases in plasma cortisol levels, whilst prolactin and testosterone levels remained unchanged. Our findings confirm that hormones can explain significant amounts of variation in contributions to offspring feeding, and that cortisol, not prolactin, is the hormone most strongly associated with pup-feeding in cooperative male meerkats

STUDY OF SALT TOLERANCE PARAMETERS IN PEARL MILLET PENNISETUM AMERICANUM L.

The genetic basis of salinity tolerance for three parameters Ct, C50 and C0 in P. americanum using the diallel analysis was investigated. Tolerance for Ct, C50, and C0 was due to both additive and dominance genetic effects with indication of over-dominance. For these three parameters, dominance is predominantly towards salt sensitivity, but it appears that in different accessions, there are different gene effects for each character. Recessive genes are evident in the salt tolerant line ICMV-94474 for Ct and C50, and in the other tolerant line 10878 are also evident for C50 and C0 for recessive genes. Salinity data set were found to be adequate totally for C50 and C0, but partially adequate for Ct. It appears in pearl millet that in some accessions recessive genes are responsible for salt tolerance for Ct, C50, and C0, but this trend is not consistent. Different (dominant / recessive) genes control each accession for Ct, C50, and C0. The maximum narrow sense and broad sense of heritability were found for C50 and this suggests that C50 is the best character for selection, rather than absolute root length. C50 is highly correlated with Ct, and C50 is also signifi cantly correlated with C0. These results suggest that the genetic bases of these genes are linked to some degree. These correlations would be of considerable value in breeding for improved salinity tolerance

The effect of dietary intervention on the metabolic and behavioural impairments generated by short term high fat feeding in the rat

AbstractPrevious studies have shown that rats fed a high calorie diet rich in saturated fat for 12weeks exhibit peripheral insulin resistance and impairments of behavioural flexibility when switched from an operant delayed matching to place (DMTP) schedule to a delayed non-matching to place (DNMTP) schedule. However, the metabolic changes evoked by feeding a high fat (HF) diet can be observed within two weeks of commencing the diet. The current study has confirmed that 4weeks exposure to an HF diet resulted in increased body weight, peripheral insulin resistance and plasma leptin. Studies performed during weeks 3 and 4 on the HF diet revealed suppressed lever pressing rates and impaired behavioural flexibility in the operant DMTP/DNMTP task. When animals fed the HF diet were then returned to a standard chow (SC) diet for 5weeks their weight and blood biochemistry no longer differed from those measured in animals that had never been exposed to the HF diet. The animals restored to the SC diet exhibited a clear ability to acquire the DNMTP schedule of reinforcement although these animals continued to lever press at a lower rate when compared with animals that received the SC diet throughout. The data suggest that exposure to an HF diet diminishes the motivation to respond for a reward and, thus, the capacity to adapt behavioural performance. This deficit was ameliorated, but not totally reversed, by the dietary intervention. If also true for humans, the results suggest that deficits in behavioural flexibility develop after only a short period on a high calorie diet but may be largely reversible through simple dietary intervention, at least in the early stages of deficit development. However, the putative effects of short-term exposure to an HF diet on behavioural motivation may persist for some time after switching to a healthier low fat diet and remain a problem for those seeking to adopt a healthier diet

Genome-wide association studies of parasite resistance, productivity and immunology traits in meat in Scottish Blackface sheep

Gastrointestinal parasitism represents a global problem for grazing ruminants, which can be addressed sustainably by breeding animals to be more resistant against infection by parasites. The aim of this study was to assess the genetic architecture underlying traits associated with gastrointestinal parasite resistance, immunological profile and production in meat sheep, and identify and characterise candidate genes affecting these traits. Data on gastrointestinal parasite infection (faecal egg counts for Strongyles (FECS) and Nematodirus (FECN) and faecal oocyst counts for Coccidia, along with faecal soiling scores (DAG), characterised by the accumulation of faeces around the perineum) and production (live weight (LWT)) were gathered from a flock Scottish Blackface lambs at three and four months of age. Data on the immune profile were also collected from a subset of these lambs at two and five months of age. Immune traits included the production of Interferon-γ (IFN-γ), Interleukin (IL)-4 and IL-10 following stimulation of whole blood with pokeweed mitogen (PWM) or antigen from the gastric parasite Teladorsagia circumcincta (T-ci), and serum levels of T. circumcincta-specific immunoglobulin A (IgA). Animals were genotyped with genome-wide DNA arrays, and a total of 1 766 animals and 45 827 Single Nucleotide Polymorphisms (SNPs) were retained following quality control and imputation. Genome-wide association studies were performed for 24 traits. The effects of individual markers with significant effects were estimated, and the genotypic effect solutions were used to estimate additive and dominance effects, and the proportion of additive genetic variance attributed to each SNP locus. A total of 15 SNPs were associated at least at a suggestive level with FECS, FECN, DAG, IgA, PWM-induced IFN-γ and IL-4, and T-ci-induced IL-10. This study uncovered 52 genes closely related to immune function in proximity to these SNPs. A number of genes encoding C-type lectins and killer cell lectin-like family members were close to a SNP associated with FECN while several genes encoding IL-1 cytokine family members were found to be associated with IgA. Potential candidate genes belonging to or in close proximity with the Major Histocompatibility Complex (MHC) were revealed, including Homeostatic Iron Regulator and butyrophilin coding genes associated with IFN-γ(PWM), and IL-17 coding genes associated with IgA. Due to the importance of the MHC in the control of immune responses, these genes may play an important role in resistance to parasitic infections. Our results reveal a largely complex and polygenic genetic profile of the studied traits in this Scottish Blackface sheep population.</p

A novel technique for retrospective genetic analysis of the response to vaccination or infection using cell-free DNA from archived sheep serum and plasma

Genetic variation is associated with differences in disease resistance and susceptibility among individuals within a population. To date, molecular genetic analyses of host responses have relied on extraction of genomic DNA from whole blood or tissue samples. However, such samples are not routinely collected during large-scale field studies. We demonstrate that cell-free genomic DNA (cfDNA) may be extracted and amplified from archived plasma samples, allowing retrospective analysis of host genetic diversity. This technique was also applicable to archived serum samples up to 35 years old and to different ruminant species. As proof of concept, we used this cfDNA approach to genotype the major histocompatibility complex (MHC) class II DRB1 locus of 224 Merino sheep which had participated in field trials of a commercial Haemonchus contortus vaccine, Barbervax®, in Australia. This identified a total of 51 different DRB1 alleles and their relative frequencies. This is the first study to examine host MHC diversity using DNA extracted from archived plasma samples, an approach that may be applied to retrospective analyses of genetic diversity and responses to vaccination or infection across different species and populations

Correlations of milk and serum element concentrations with production and management traits in dairy cows

The present study investigated the potential consequences, positive or negative, that selection for favorable production-related traits may have on concentrations of vitamin B(12) and key chemical elements in dairy cow milk and serum and the possible impact on milk healthiness, and associated benefits, for the dairy product consumer. Milk and serum samples (950 and 755, respectively) were collected from Holstein-Friesian dairy cows (n = 479) on 19 occasions over a 59-mo period, generating 34,258 individual records, and analyzed for concentrations of key trace and quantity elements, heavy metals, and milk vitamin B(12). These data were then matched to economically important production data (milk, fat, and protein yield) and management data (dry matter intake, liveweight, and body condition score). Multivariate animal models, including full pedigree information, were used to analyze data and investigate relationships between traits of interest. Results highlighted negative genetic correlations between many quantity and trace elements in both milk and serum with production and management traits. Milk yield was strongly negatively correlated with the milk quantity elements Mg and Ca (genetic correlation between traits, r(a) = −0.58 and −0.63, respectively) as well as the trace elements Mn, Fe, Ni, Cu, Zn, and Mo (r(a) = −0.32, −0.58, −0.52, −0.40, −0.34, and −0.96, respectively); and in serum, Mg, Ca, Co, Fe, and Zn (r(a) = −0.50, −0.36, −0.68, −0.54, and −0.90, respectively). Strong genetic correlations were noted between dry matter intake with V (r(a) = 0.97), Fe (r(a) = −0.69), Ni (r(a) = −0.81), and Zn (r(a) = −0.75), and in serum, strong negative genetic correlations were observed between dry matter intake with Ca and Se (r(a) = −0.95 and −0.88, respectively). Body condition score was negatively correlated with serum P, Cu, Se, and Pb (r(a) = −0.45, −0.35, −0.51, and −0.64, respectively) and positively correlated with Mn, Fe, and Zn (r(a) = 0.40, 0.71, and 0.55, respectively). Our results suggest that breeding strategies aimed at improving economically important production-related traits would most likely result in a negative impact on levels of beneficial nutrients within milk for human consumption (such as Mg, Ca, Fe, Zn, and Se)

High intensity exercise as a dishabituating stimulus restores counterregulatory responses in recurrently hypoglycemic rodents

Hypoglycemia is a major adverse effect of insulin therapy for people with type 1 diabetes (T1D). Profound defects in the normal counterregulatory response to hypoglycemia explain the frequency of hypoglycemia occurrence in T1D. Defective counterregulation results to a large extent from prior exposure to hypoglycemia per se, leading to a condition called impaired awareness of hypoglycemia (IAH), the cause of which is unknown. In the current study, we investigate the hypothesis that IAH develops through a special type of adaptive memory referred to as habituation. To test this hypothesis, we used a novel intense stimulus (high-intensity exercise) to demonstrate two classic features of a habituated response, namely dishabituation and response recovery. We demonstrate that after recurrent hypoglycemia the introduction of a novel dishabituating stimulus (a single burst of high-intensity exercise) in male Sprague-Dawley rats restores the defective hypoglycemia counterregulatory response. In addition, the rats showed an enhanced response to the novel stimulus (response recovery). We make the further observation using proteomic analysis of hypothalamic extracts that high-intensity exercise in recurrently hypoglycemic rats increases levels of a number of proteins linked with brain-derived neurotrophic factor signaling. These findings may lead to novel therapeutic approaches for individuals with T1D and IAH.</jats:p

STUDY OF SALT TOLERANCE PARAMETERS IN PEARL MILLET PENNISETUM AMERICANUM L.

The genetic basis of salinity tolerance for three parameters Ct, C50 and C0 in P. americanum using the diallel analysis was investigated. Tolerance for Ct, C50, and C0 was due to both additive and dominance genetic effects with indication of over-dominance. For these three parameters, dominance is predominantly towards salt sensitivity, but it appears that in different accessions, there are different gene effects for each character. Recessive genes are evident in the salt tolerant line ICMV-94474 for Ct and C50, and in the other tolerant line 10878 are also evident for C50 and C0 for recessive genes. Salinity data set were found to be adequate totally for C50 and C0, but partially adequate for Ct. It appears in pearl millet that in some accessions recessive genes are responsible for salt tolerance for Ct, C50, and C0, but this trend is not consistent. Different (dominant / recessive) genes control each accession for Ct, C50, and C0. The maximum narrow sense and broad sense of heritability were found for C50 and this suggests that C50 is the best character for selection, rather than absolute root length. C50 is highly correlated with Ct, and C50 is also signifi cantly correlated with C0. These results suggest that the genetic bases of these genes are linked to some degree. These correlations would be of considerable value in breeding for improved salinity tolerance