| Home | << 1 2 3 4 5 >> |
|
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.
Keywords: Age Factors; Animals; Cell Line, Transformed; Cells, Cultured; Female; Inflammation Mediators/*physiology; Kidney/metabolism; Mesangial Cells/metabolism; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred MRL lpr; Mice, Knockout; Nitric Oxide/biosynthesis; Nitric Oxide Synthase Type II/biosynthesis/genetics; PPAR gamma/*biosynthesis/*genetics/metabolism; Up-Regulation/immunology
|
|
Nicol, C. J., Davidson, H. P. D., Harris, P. A., Waters, A. J., & Wilson, A. D. (2002). Study of crib-biting and gastric inflammation and ulceration in young horses. Vet. Rec., 151(22), 658–662.
Abstract: Nineteen young horses that had recently started to perform the stereotypy of crib-biting were compared with 16 non-stereotypic horses for 14 weeks. After initial observations of their behaviour and an endoscopic examination of the condition of their stomachs, the horses were randomly allocated to a control or an antacid diet At the start of the trial, the stomachs of the crib-biting foals were significantly more ulcerated and inflamed than the stomachs of the normal foals. In addition, the faecal pH of the crib-biting foals (6.05) was significantly lower than that of the normal foals (6.58). The antacid diet resulted in a significant improvement in the condition of the horses' stomachs. The crib-biting behaviour declined in most of the foals, regardless of their diet, but tended to decline to a greater extent in the foals on the antacid diet.
Keywords: Animal Husbandry/methods; Animals; Antacids/therapeutic use; *Behavior, Animal; Diet/veterinary; Endoscopy, Gastrointestinal/veterinary; Feces/chemistry; Female; Gastritis/diet therapy/physiopathology/*veterinary; Horse Diseases/diet therapy/*physiopathology/psychology; Horses; Hydrogen-Ion Concentration; Male; Random Allocation; Stereotyped Behavior/*physiology; Stomach Ulcer/diet therapy/physiopathology/*veterinary; Treatment Outcome; Weaning
|
|
Waters, A. J., Nicol, C. J., & French, N. P. (2002). Factors influencing the development of stereotypic and redirected behaviours in young horses: findings of a four year prospective epidemiological study. Equine Vet J, 34(6), 572–579.
Abstract: Stereotypies are invariant and repetitive behaviour patterns that seemingly have no function, which tend to develop in captive animals faced with insoluble problems and may be indicative of reduced welfare. A 4 year prospective study of the factors influencing the development of stereotypic and redirected behaviours (abnormal behaviour) in a population of 225 young Thoroughbred and part-Thoroughbred horses was conducted between 1995 and 1999. Abnormal behaviour affected 34.7% of the population. Multivariable analysis showed that foals of low- or middle-ranking mares were less likely to develop abnormal behaviour than foals of dominant mares (rate ratio (RR) 0.23, P<0.01; RR 0.48, P<0.01, respectively). Weaning by confinement in a stable or barn was associated with an increased rate of development of abnormal behaviour, compared with paddock-weaning (RR 2.19, P<0.05), and housing in barns, rather than at grass after weaning, was associated with a further increase (RR 2.54, P<0.01). Specific stereotypic and redirected behaviours were then considered as separate outcomes. Crib-biting was initiated by 10.5% of horses at median age 20 weeks, weaving by 4.6% of horses at median age 60 weeks, box-walking by 2.3% of horses at median age 64 weeks and wood-chewing by 30.3% of horses at median age 30 weeks. Wood-chewing developed at a lower rate in horses born to subordinate or mid-ranking mares than in horses born to dominant mares (RR 0.29, P<0.01; RR 0.41, P<0.01, respectively), and at a higher rate in horses kept in barns or stables rather than at grass after weaning (RR 4.49, P<0.001; RR 1A6, P<0.001, respectively). Feeding concentrates after weaning was associated with a 4-fold increase in the rate of development of crib-biting (RR 4.12, P = 0.02). The results of this study support the idea that simple changes in feeding, housing and weaning practices could substantially lower the incidence of abnormal behaviour in young horses.
|
|
Abeyesinghe, S. M., Nicol, C. J., Wathes. C.M., & Randall, J. M. (2001). Development of a raceway method to assess aversion of domestic fowl to concurrent stressors. Behav. Process., 56(3), 175–194.
Abstract: The requirement for assessing the effects of stressor combinations in improving the welfare of animals has not been widely recognised. Knowledge of the effects of concurrent stressors is needed to improve environments such as transport, where animals are presented with many simultaneous challenges. However, no method for measuring the effects of different stressors with a common unit is currently available. A locomotor passive avoidance method was developed as a common currency measure of the aversion of domestic fowl to concurrent stressors, using vibrational and thermal stressors as an exemplar. Juvenile fowl, fasted overnight, were trained to run a raceway into a goal-box for small food rewards (FR1). When running consistently, the reinforcement schedule was superimposed with a FR5 treatment schedule (60 min confinement in the goal-box with either a control of no other stressors [N] or concurrent vibration and thermal stressors [VT]). Subsequent latency to return to the goal-box was recorded as a measure of aversion. The factors affecting bird response were addressed in a series of experiments to optimise the method and clarify interpretation of results. Pre-feeding (20% ration 2 h prior to testing) did not affect response, but increasing the number of treatment presentations facilitated learning and increased method sensitivity. Treatment responses were consistent across experiments; overall VT was avoided (P<0.001), but N was not. However, there was large individual variation in response to VT. A final experiment indicated that, given a visual discriminatory cue, birds were capable of learning the required association between entering the goal-box and receiving the treatment, suggesting that the delay responses were due to aversion rather than the immediate impact of treatment on ability to respond. Further work is required to test the singular stressors, but the method retains common currency potential for assessing aversion to multiple stressors.
|
|
McGreevy, P. D., French, N. P., & Nicol, C. J. (1995). The prevalence of abnormal behaviours in dressage, eventing and endurance horses in relation to stabling. Vet. Rec., 137(2), 36–37.
Abstract: The behaviour of horses competing in different disciplines was studied and the relationship between the time they spent out of the stable and the prevalence of abnormal behaviour was examined. The owners of dressage, eventing and endurance horses were sent a questionnaire and a total of 1101 responses were received, giving data on 1750 horses. The behaviours studied were wood-chewing, weaving, crib-biting/wind-sucking and box-walking. The reported percentage prevalences of abnormal behaviour for the dressage, eventing and endurance horses were 32.5, 30.8 and 19.5, respectively. The relationship between the time spent in the stable and the prevalence of abnormal behaviour was examined by chi 2 tests which showed that there were significant linear trends for the eventing group (P < 0.001) and the dressage group (P < 0.05). It is concluded that the time a horse spends out of the stable is related to the discipline for which it is being trained and in dressage and eventing horses the time spent in a stable is correlated with an increased risk of abnormal behaviour.
|
|
Lindberg, A. C., Kelland, A., & Nicol, C. J. (1999). Effects of observational learning on acquisition of an operant response in horses. Appl. Anim. Behav. Sci., 61(3), 187–199.
Abstract: The effect of observational learning on the acquisition of an operant response was examined in eighteen riding horses and ponies. The test horses were randomly divided into three groups of six and individually exposed to one of three treatments. An additional horse was trained as a demonstrator, to perform the operant response. The observer horses watched either the demonstrator performing the bin-opening response (Group D+B); the demonstrator standing passively (Group D); or the operant bin in the absence of the demonstrator (Group B). Observers had access to and were free to interact with an identical bin during testing. Observers in Groups D+B and D were socially familiar with the demonstrator. Each test horse was tested once a day for 10 days. An ANOVA revealed no significant differences between treatment groups in the number of responses or the time taken to reach the learning criterion. However, there were highly significant differences between breed types, with non-warmbloods performing more bouts of opening the bin and feeding (p=0.02), feeding from the bin sooner (p=0.01) and reaching the criterion for learning sooner than warmbloods (p=0.05). There was also a significant negative linear relationship between horses' ages and time spent investigating the bin, with younger horses performing more investigative behaviour (y=-3.08x+106.86; p=0.02).
|
|
Clarke, J. V., Nicol, C. J., Jones, R., & McGreevy, P. D. (1996). Effects of observational learning on food selection in horses. Appl. Anim. Behav. Sci., 50(2), 177–184.
Abstract: Fourteen riding horses of mixed age and breed were randomly allocated to observer and control treatments. An additional horse was pre-trained as a demonstrator to walk the 13.8 m length of the test arena and select one of two food buckets using colour and pattern cues. Observer horses were exposed to correct performances of the task by the trained demonstrator, for 20 trials held over 2 days. Control horses were subjected to the same handling and placement procedures as the observer horses but without exposure to the behaviour of the demonstrator. The third day for all subjects was designated as a test day. Each subject was released individually in a predetermined place in the arena, and the latency to walk the length of the test arena to the food buckets, the latency to feed, the identity of the bucket approached and the identity of the bucket selected were recorded on ten consecutive trials. During tests both food buckets contained food to minimize the possibility of individual trial and error learning. On the first trial the mean latency to approach the goal area was 18 s for observer horses, compared with 119 s for control horses (t = 2.8, d.f. = 12, P < 0.01) and the mean latency to eat was 35 s for observer horses, compared with 181 s for control horses (t = 4.86, d.f. = 11, P < 0.001). However, observer horses were no more likely to choose the demonstrated bucket than control horses on the first trial. Twelve of the 14 horses decreased their latency to approach the goal area during the series of ten trials, but there were no significant changes in the buckets selected.
Keywords: Horse; Observational learning; Food discrimination
|
|
Nicol, C. J. (2006). How animals learn from each other. Appl. Anim. Behav. Sci., 100(1-2), 58–63.
Abstract: This paper explores ways by which animals may learn from one another, using examples drawn mostly from the chicken, an animal for which social learning is likely to be less dangerous than individual learning. In early life, the behaviour of the hen is important in encouraging chicks to peck at edible items. Maternal display not only attracts chicks to profitable food items, but also redirects their attention away from harmful or non-profitable items. Older chicks can enhance their foraging success by observing the behaviour of conspecifics within their own social group. Hens have been trained to perform a novel behaviour (key-pecking for food) by observation of a trained demonstrator bird. Moreover, observers learnt most from watching dominant demonstrators. Thus the ability to learn from others is not `fixed', but depends on the context and the social identity of both the observer and the demonstrator.
Keywords: Social learning; Chickens; Demonstrators; Dominance
|
|
Nicol, C. J. (1995). The social transmission of information and behaviour. Appl. Anim. Behav. Sci., 44(2-4), 79–98.
Abstract: Social influences on established behaviour and on the acquisition of new information and behaviour are reviewed. Distinctions between social facilitation and contagious behaviour are drawn and suggestions for further research on contagious behaviour are made. Socially derived visual, olfactory and auditory cues are considered as important influences on behaviour and subsequent learning. The evidence supporting two potential mechanisms of social learning, i.e. stimulus enhancement followed by individual learning, and imitation, is reviewed in detail. It is argued that the functions of social learning are similarly heterogeneous and include motor skill acquisition, gathering of environmental information, and social conformity. Factors affecting the spread of socially acquired skills, including the social relationship between demonstrator and observer, are highlighted. Lastly, the few studies of social learning that have been conducted with domestic species are reviewed and potential applied goals that could stimulate further research in this area are suggested.
|
|
Nicol, C. J., & Pope, S. J. (1999). The effects of demonstrator social status and prior foraging success on social learning in laying hens. Anim. Behav., 57(1), 163–171.
Abstract: Opportunities for social learning within a group of animals are likely to be influenced by the social dynamics of that group. Some individuals may be more influential demonstrators than others even when there are no differences in their skill level or performance. In this study of domestic hens,Gallus gallus domesticus, differences in demonstrator salience were examined. From 24 separate flocks we selected as demonstrators a dominant cockerel, a dominant hen, a mid-ranking hen or a subordinate hen. Demonstrators were pretrained to perform an operant discrimination task to obtain food. Six observers from each flock individually watched the demonstrator perform the task for four 5-min sessions held on consecutive days. On the fifth day observers were tested individually in the operant chamber. We analysed data from 19 flocks, where there were no quantitative differences in demonstrator performance. Observer hens of relatively high social status performed more correct operant pecks than observer hens of relatively low social status. Demonstrator category also had a significant effect on subsequent observer behaviour. Hens that had observed cockerels performed very few general pecks or operant pecks. Hens that had observed dominant hens performed more operant pecks, but hens that had observed sub-ordinate hens performed more general pecks in the chamber. The results suggested either that there was an interaction between dominance and gender in demonstrator salience or that dominant hens might have been influential because of some factor imperfectly associated with their dominance status. A possible candidate was the foraging ability of the dominant hens. In a second experiment using the same protocol, we manipulated the prior foraging success of dominant hens from four additional flocks but this had no significant effect on their subsequent influence as demonstrators.
|