Abstract: The use of noninvasive measures of hypothalamic-pituitary-adrenal (HPA) axis function is of growing interest among preclinical and clinical investigators. This report describes a method for the repeated assessment of salivary free cortisol in awake, unrestrained squirrel monkeys (Saimiri sciureus) based on a saliva sampling technique previously developed for rhesus monkeys. Individually housed adult male squirrel monkeys were trained to chew on dental rope attached to a pole, from which saliva was extracted by centrifugation and analyzed for cortisol by radioimmunoassay (RIA). Eight of nine monkeys readily acquired the task, reliably providing adequate saliva samples for the assay. Salivary free cortisol levels were examined in these subjects under basal conditions and in response to two types of neuroendocrine challenge. Levels of salivary free cortisol showed relatively low intra- and interindividual variability, with mean individual morning levels ranging between 17.1 and 37.9 µg/dl. Squirrel monkeys demonstrated a consistent daily rhythm in salivary free cortisol ranging from a high of 27.4 ± 5.2 µg/dl (mean ± SEM) at 12 P.M. to a low of 7.5 ± 1.6 µg/dl at 6 P.M.. Intravenous (IV) challenges with 1 µg/kg ACTH, or 10 and 50 µg/kg CRF resulted in significant increases in salivary free cortisol. The described sampling technique provides a reliable and sensitive means for repeated measurement of HPA activity in unrestrained, awake squirrel monkeys. In addition, our findings illustrate several features of HPA system rhythmicity and reactivity using salivary cortisol instead of blood plasma or serum. Am. J. Primatol. 60:69–75, 2003. © 2003 Wiley-Liss, Inc.

Abstract: Delayed onset muscle soreness (DOMS) is a familiar experience for the elite or novice athlete. Symptoms can range from muscle tenderness to severe debilitating pain. The mechanisms, treatment strategies, and impact on athletic performance remain uncertain, despite the high incidence of DOMS. DOMS is most prevalent at the beginning of the sporting season when athletes are returning to training following a period of reduced activity. DOMS is also common when athletes are first introduced to certain types of activities regardless of the time of year. Eccentric activities induce micro-injury at a greater frequency and severity than other types of muscle actions. The intensity and duration of exercise are also important factors in DOMS onset. Up to six hypothesised theories have been proposed for the mechanism of DOMS, namely: lactic acid, muscle spasm, connective tissue damage, muscle damage, inflammation and the enzyme efflux theories. However, an integration of two or more theories is likely to explain muscle soreness. DOMS can affect athletic performance by causing a reduction in joint range of motion, shock attenuation and peak torque. Alterations in muscle sequencing and recruitment patterns may also occur, causing unaccustomed stress to be placed on muscle ligaments and tendons. These compensatory mechanisms may increase the risk of further injury if a premature return to sport is attempted.

Abstract: We describe two field experiments with wild guppies, Poecilia reticulata, in Trinidad that demonstrated that guppies can acquire foraging and predator escape-response information from conspecifics. In the foraging experiment, subjects were presented with two distinctly marked feeders in their home rivers. One feeder contained a conspecific shoal in a transparent container. Guppies preferred to enter the feeder containing this artificial shoal over the other feeder. In a test phase, the artificial shoal was removed and the feeders replaced at the testing site after a 5-min delay. More guppies entered the feeder that had contained the artificial shoal over the other feeder, a difference that can be explained only by the fish learning the characteristics or location of the feeder during the training phase. We suggest that subjects acquired a foraging patch preference through a propensity to approach feeding conspecifics, a local enhancement process. In the predator escape-response experiment, naive 'observer' guppies could avoid an approaching trawl net by escaping through either a hole to which 'demonstrator' guppies had been trained or through an alternative hole. When the demonstrators were present, the naive observers escaped more often and more rapidly by the demonstrated route than the alternative route. When the demonstrators were removed, observers maintained a route preference according to the training of their demonstrators, which suggests that the observers had learned an escape route through following or observing their more knowledgeable conspecifics. Thus, both experiments reveal that guppies can socially learn in the wild. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.

Abstract: Environmental enrichment is a simple and effective means of improving animal welfare in any species – companion, farm, laboratory and zoo. For many years, it has been a popular area of research, and has attracted the attention and concerns of animal keepers and carers, animal industry professionals, academics, students and pet owners all over the world.