|
|
Hothersall, B., Harris, P., Sörtoft, L., & Nicol, C. J. (2010). Discrimination between conspecific odour samples in the horse (Equus caballus). Appl. Anim. Behav. Sci., 126(1-2), 37–44.
Abstract: Behavioural observations suggest that smell is important in social discriminations between horses but balanced studies of this capacity are lacking. We used a habituation-discrimination procedure to investigate the ability of horses to distinguish between pairs of odour samples from different individuals. In Study 1, separate tests were conducted for urine, faeces or fleece fabric previously rubbed on the coat (to pick up body odour samples (BOS)) and donor pairs differed in sex, and age. 10 pregnant mares each underwent three tests, one per sample type. A test consisted of three successive 2-min presentations of a sample from Individual A with a simultaneous presentation of a sample from Individual B during the final presentation. Doubly repeated measures ANOVA indicated a main effect of sample type on investigative response (df = 2, f = 7.98, P = 0.004): durations were longer for BOS than for urine or faeces but habituation across trials was most consistent for urine. In the final presentation, mares demonstrated discrimination by investigating the novel urine sample (B) more than the repeated sample (novel: median 8.0 s, IQR = 10; repeated: median 2.5 s, IQR = 6; z = -2.558, P = 0.008). In Study 2, urine samples from castrated male donors were used and neither mares nor their 4-month-old foals discriminated between samples from different individuals in the final presentation. The findings suggest that urine odour may contain some information that horses can use to discriminate between conspecifics. This may be limited to the level of broad categories such as sex or reproductive status; further investigation is needed to reveal what functional information can be transmitted and what compounds are involved.
|
|
|
|
Hothersall, B., Gale, E., Harris, P., & Nicol, C. (2010). Cue use by foals (Equus caballus) in a discrimination learning task. Anim. Cogn., 13(1), 63–74.
Abstract: Abstract Discrimination learning studies suggest that horses learn more easily using spatial than visible object-specific (OS) cues. However, spatial cues have generally confounded intra-array, distal and/or egocentric spatial information. It is also unclear whether conflicting cues compete for association or are redundantly encoded, and furthermore, the influence of prior experiences or training has not been quantified so far. We examined the effect of cue modality on unweaned foals’ performance in a discrimination learning task. After a pilot study confirmed that horses could perform the required OS cue discrimination, nine foals learnt to find food in one of three covered buckets, in any of four positions within a test arena. In Stage 1 the rewarded bucket was signified both by OS cues (pattern) and by relative spatial cues (position). On reaching criterion, cues were separated and foals had to ignore the inappropriate cue (Stage 2). Foals assigned to follow spatial cues (n = 5) completed Stage 2 faster than foals for whom OS cues remained consistent (n = 4). Spatial group foals all reached criterion without delay; no foal in the OS group reached criterion within the testing period. OS group foals initially persisted in responding to the previously correct position, adopting spatially-based strategies when this proved unsuccessful. The findings show for the first time that, even in the absence of distal spatial information, intra-array spatial cues were more salient than OS cues for foals in a food-finding task and learning appeared rather inflexible.
|
|
|
|
Haslam, S. M., Brown, S. N., Wilkins, L. J., Kestin, S. C., Warriss, P. D., & Nicol, C. J. (2006). Preliminary study to examine the utility of using foot burn or hock burn to assess aspects of housing conditions for broiler chicken. Br Poult Sci, 47(1), 13–18.
Abstract: 1. Eleven broiler chicken farms, representing 4 production system types, were visited during the last 5 d of the flock cycle: bird and flock details were recorded. Litter friability was assessed at 9 sites within the house, atmospheric ammonia was measured at three sites and bird cleanliness was assessed on a numerical rating scale. 2. For these flocks, hock burn, foot burn and breast burn were measured at the processing plant by standardised assessors. 3. Significant correlations were identified between the percentage of birds with foot burn and average litter score, average house ammonia concentrations and feather score. 4. No correlation was found between the percentage of birds with hock burn or breast burn and average litter scores, average ammonia concentrations or feather score. 5. No correlation was found between stocking density and foot burn, hock burn or breast burn.6. If confirmed, these findings may have implications for the draft EU Broiler Directive, for which it is proposed that permitted stocking density on farm may be determined by the incidence and severity of contact dermatitis measured on plant.
|
|
|
|
Harman, F. S., Nicol, C. J., Marin, H. E., Ward, J. M., Gonzalez, F. J., & Peters, J. M. (2004). Peroxisome proliferator-activated receptor-delta attenuates colon carcinogenesis. Nat Med, 10(5), 481–483.
Abstract: Peroxisome proliferator-activated receptor-delta (PPAR-delta; also known as PPAR-beta) is expressed at high levels in colon tumors, but its contribution to colon cancer is unclear. We examined the role of PPAR-delta in colon carcinogenesis using PPAR-delta-deficient (Ppard(-/-)) mice. In both the Min mutant and chemically induced mouse models, colon polyp formation was significantly greater in mice nullizygous for PPAR-delta. In contrast to previous reports suggesting that activation of PPAR-delta potentiates colon polyp formation, here we show that PPAR-delta attenuates colon carcinogenesis.
|
|
|
|
Guo, G. L., Moffit, J. S., Nicol, C. J., Ward, J. M., Aleksunes, L. A., Slitt, A. L., et al. (2004). Enhanced acetaminophen toxicity by activation of the pregnane X receptor. Toxicol Sci, 82(2), 374–380.
Abstract: The pregnane X receptor (PXR) is a ligand-activated transcription factor and member of the nuclear receptor superfamily. Activation of PXR represents an important mechanism for the induction of cytochrome P450 3A (CYP3A) enzymes that can convert acetaminophen (APAP) to its toxic intermediate metabolite, N-acetyl-p-benzoquinone imine (NAPQI). Therefore, it was hypothesized that activation of PXR plays a major role in APAP-induced hepatotoxicity. Pretreatment with the PXR activator, pregnenolone 16alpha-carbonitrile (PCN), markedly enhanced APAP-induced hepatic injury, as revealed by increased serum ALT levels and hepatic centrilobular necrosis, in wild-type but not in PXR-null mice. Further analysis showed that following PCN treatment, PXR-null mice had lower CYP3A11 expression, decreased NAPQI formation, and increased maintenance of hepatic glutathione content compared to wild-type mice. Thus, these results suggest that PXR plays a critical role in APAP-induced hepatic toxicity, probably by inducing CYP3A11 expression and hence increasing bioactivation.
|
|
|
|
Giles, S. L., Nicol, C. J., Harris, P. A., & Rands, S. A. (2015). Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus). Applied Animal Behaviour Science, .
Abstract: Abstract The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, Equus caballus. Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect. More dominant (p = 0.001) individuals generally had a higher body condition score (p = 0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS >= 7/9, p = 0.005). There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank (p < 0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.
|
|
|
|
Gavrilova, O., Haluzik, M., Matsusue, K., Cutson, J. J., Johnson, L., Dietz, K. R., et al. (2003). Liver peroxisome proliferator-activated receptor gamma contributes to hepatic steatosis, triglyceride clearance, and regulation of body fat mass. J Biol Chem, 278(36), 34268–34276.
Abstract: Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that mediates the antidiabetic effects of thiazolidinediones. PPAR gamma is present in adipose tissue and becomes elevated in fatty livers, but the roles of specific tissues in thiazolidinedione actions are unclear. We studied the function of liver PPAR gamma in both lipoatrophic A-ZIP/F-1 (AZIP) and wild type mice. In AZIP mice, ablation of liver PPAR gamma reduced the hepatic steatosis but worsened the hyperlipidemia, triglyceride clearance, and muscle insulin resistance. Inactivation of AZIP liver PPAR gamma also abolished the hypoglycemic and hypolipidemic effects of rosiglitazone, demonstrating that, in the absence of adipose tissue, the liver is a primary and major site of thiazolidinedione action. In contrast, rosiglitazone remained effective in non-lipoatrophic mice lacking liver PPAR gamma, suggesting that adipose tissue is the major site of thiazolidinedione action in typical mice with adipose tissue. Interestingly, mice without liver PPAR gamma, but with adipose tissue, developed relative fat intolerance, increased adiposity, hyperlipidemia, and insulin resistance. Thus, liver PPAR gamma regulates triglyceride homeostasis, contributing to hepatic steatosis, but protecting other tissues from triglyceride accumulation and insulin resistance.
|
|
|
|
Freire, R., Wilkins, L. J., Short, F., & Nicol, C. J. (2003). Behaviour and welfare of individual laying hens in a non-cage system. Br Poult Sci, 44(1), 22–29.
Abstract: 1. A leg band containing a transponder was fitted to 80 birds in a perchery containing 1,000 birds. 2. The transponder emitted a unique identification number when a bird walked on one of 8 flat antennae on the floor. The recording apparatus was used to measure the amount of time that each of the tagged birds spent on the slatted and littered areas in a 6-week period. 3. Some birds spent long periods of time on the slats, possibly as a means of avoiding repeated attacks. Duration on the slats was greatest in birds with the worst (as opposed to better) feather scores of the head, back and tail regions. 4. Birds that spent long periods on the slats were lighter than other birds at both 39 weeks of age and 72 weeks of age and had greater back, head and tail feather damage, consistent with these birds being victims of pecking. 5. Tagged birds received a social avoidance test outside the perchery at 39 weeks of age, which suggested that birds retreated to the slats in response to pecks rather than just to close proximity to other birds. 6. The failure to find that duration on the slats was related to anatomical indicators of stress (liver, spleen and bursa of Fabricius) suggests that retreating to the slats following pecking attenuates physiological stress responses. 7. We conclude that the provision of areas where birds in a large group can avoid pecking may improve the welfare of a minority of victimised birds.
|
|
|
|
Dixon, G., Green, L. E., & Nicol, C. J. (2006). Effect of diet change on the behavior of chicks of an egg-laying strain. J Appl Anim Welf Sci, 9(1), 41–58.
Abstract: Injurious pecking has serious welfare consequences in flocks of hens kept for egg laying, especially when loose-housed. Frequent diet change is a significant risk for injurious pecking; how the mechanics of diet change influence pecking behavior is unknown. This study investigated the effect of diet change on the behavior of chicks from a laying strain. The study included a 3-week familiarity phase: 18 chick pairs received unflavored feed (Experiment 1); 18 pairs received orange oil-flavored (Experiment 2). All chicks participated in a dietary preference test (P); a diet change (DC); or a control group (C), 6 scenarios. All P chicks preferred unflavored feed. In Experiment 1, DC involved change from unflavored to orange-flavored; Experiment 2, orange- flavored to unflavored. Compared with controls, Experiment 2 DC chicks exhibited few behavioral differences; Experiment 1 DC chicks exhibited increased behavioral event rates on Days 1 and 7. They pecked significantly longer at their environment; by Day 7, they showed significantly more beak activity. There was little evidence of dietary neophobia. Change from more preferred to less preferred feed led to increased activity and redirected pecking behavior.
|
|
|
|
Crosby, M. B., Zhang, J., Nowling, T. M., Svenson, J. L., Nicol, C. J., Gonzalez, F. J., et al. (2006). Inflammatory modulation of PPAR gamma expression and activity. Clin Immunol, 118(2-3), 276–283.
Abstract: Nitric oxide (NO) production increases with age in the lupus-prone MRL/lpr mouse, paralleling disease activity. One mechanism for excess NO production in MRL/lpr mice may be a defect in down-regulatory mechanisms of the iNOS pathway. A potential modulator of NO is the nuclear hormone receptor peroxisome proliferation activated receptor gamma (PPARgamma). We demonstrate that renal PPARgamma protein expression was altered as disease progressed in MRL/lpr mice, which paralleled increased iNOS protein expression. Additionally, MRL/lpr-derived primary mesangial cells expressed less PPARgamma than BALB/c mesangial cells and produced more NO in response to LPS and IFNgamma. Furthermore, PPARgamma activity was reduced in mesangial cells following exposure to inflammatory mediators. This activity was restored with the addition of a NOS enzyme inhibitor. These results indicate that the activation of inflammatory pathways may lead to reduced activity and expression of PPARgamma, further exacerbating the disease state.
|
|
