Fatty acid profiles of serum lipid fractions change minimally in sled dogs before and after short bouts of exercise

Although emerging data suggests a greater influence of gluconeogenic precursors, endurance sled dogs have long appeared to rely heavily on fatty acid oxidation for sustained energy production. However, much of the research investigating lipid utilization during exercise in sled dogs has been carried out with dogs subjected to extended bouts of endurance exercise. Less is known about changes in fatty acid composition in endurance training sled dogs subjected to short bouts of exercise, and fewer data define how fatty acid composition may change in distinct lipid fractions. As such, the study objective was to assess whether short bouts of submaximal exercise would affect fatty acid profiles of serum lipid fractions in endurance training sled dogs. Fifteen privately-owned Siberian huskies were used (8 females: 4 intact, 4 spayed; 7 males: 2 intact, 5 neutered), with an average age of 4.6 ± 2.5 years and body weight of 24.8 ± 4.2 kg. Throughout the diet acclimation and remainder of the study, all dogs were fed a dry extruded diet that met or exceeded all AAFCO nutrient recommendations. Dogs were weighed weekly and fed to maintain baseline body weight. A 12-week exercise regimen was designed to incorporate weekly increases in running distance, but weather played a role in setting the daily distance. On weeks 2, 5, and 11, an exercise challenge was implemented whereby dogs would run 4 km at 15 km/h in teams of 4. Pre- and post-exercise blood samples were taken, and gas chromatography was used to evaluate fatty acid profiles of all identified serum lipid fractions (cholesterol ester, diacylglycerol, free fatty acid, phospholipids, triglyceride). Data were analyzed using PROC MIXED of SAS, with dog as a random effect and week and sampling time point as fixed effects. Composition of oleic (18:1n9), linoleic (18:2n6), and alpha-linolenic (18:3n3) acids in the free fatty acid fraction decreased by ∼9, 10, and 60%, respectively, following exercise (P ≤ 0.05). The results presented herein suggest that aside from a degree of depletion of these 18-carbon unsaturated fatty acids, short bouts of submaximal exercise do not induce considerable changes to sled dog fatty acid profiles

Hydration status affects thirst and salt preference but not energy intake or postprandial ghrelin in healthy adults : a randomised crossover trial

Background Few studies have investigated the effect of hydration status on appetite for food in healthy adults. Prior work suggests hydration status does not alter appetite or energy intake, with mixed findings regarding appetite hormone secretion. However, an extensive investigation into both the psychological and physiological appetitive responses to hydration status has never been conducted. Objective To investigate the effect of hydration status on multiple facets of appetite. Design After 3 days pre-trial standardization, a range of appetite tasks were conducted when hypohydrated (HYPO) and euhydrated (EUHY) in 16 healthy participants (8 men). Hydration status was manipulated via dehydration in a heat tent for 60 min and subsequent fluid restriction (HYPO) or replacement (EUHY). The next day, a food reward computer task was completed followed by an ad libitum pasta meal. Pre- and post-prandial visual analogue scales assessing hunger, fullness, and flavour desires (sweet, salty, savoury and fatty) were additionally completed. Blood samples were taken the previous day before the hydration interventions in a euhydrated state, and in the fasted and post-prandial state during HYPO and EUHY. Results HYPO induced -1.9 ± 1.2% body mass change, compared to -0.2 ± 0.6% , with accompanying changes in markers of hypohydration which were not seen during EUHY. A higher desire for foods was associated with a higher water content but the association was weaker in EUHY compared to HYPO, (β= -0.33 mm/g of food water content, p < 0.001) in the food reward task. Visual analogue scales showed similar hunger and fullness between interventions, but during HYPO there was consistently higher thirst (average range in difference 27–32 mm across all time points) and lower fasted desire for salt (−23, 95% CI −10, −35 mm). Ad libitum energy intake (HYPO 1953 ± 742 kJ, EUHY 2027 ± 926 kJ; p = 0.542) and post-prandial ghrelin concentrations (HYPO 180 ± 65 pg mL−1, EUHY 188 ± 71 pg mL−1; p = 0.736) were similar by hydration status. Conclusions An acute manipulation to hydration status altered desire for salt and foods of differing water contents, but did not influence energy intake at an ad libitum pasta meal. Further research should investigate whether these appetites would alter food choice

Handling Of Virtual Contact In Immersive Virtual Environments: Beyond Visuals

This paper addresses the issue of improving the perception of contact that users make with purely virtual objects in virtual environments. Because these objects have no physical component, the user&apos;s perceptual understanding of the material properties of the object, and of the nature of the contact, is hindered, often limited solely to visual feedback. Many techniques for providing haptic feedback to compensate for the lack of touch in virtual environments have been proposed. These systems have increased our understanding of the nature of how humans perceive contact. However, providing effective, general-purpose haptic feedback solutions has proven elusive. We propose a more-holistic approach, incorporating feedback to several modalities in concert. This paper describes a prototype system we have developed for delivering vibrotactile feedback to the user. The system provides a low-cost, distributed, portable solution for incorporating vibrotactile feedback into various types of systems. We discuss different parameters that can be manipulated in order to provide different sensations, propose ways in which this feedback can be combined with feedback of other modalities to create a better understanding of virtual contact, and describe possible applications. KEY WORDS: haptic feedback; multimodal interaction; vibrotactile feedback 1

Investigating the effects of incremental conditioning and supplemental dietary tryptophan on the voluntary activity and behaviour of mid-distance training sled dogs.

Serotonin is a neurotransmitter synthesized by the amino acid tryptophan, that has the potential to impact the behaviour and activity of dogs. The objective of this study was to assess the effects of supplemental tryptophan and a 12-week incremental training regimen on the voluntary activity and behaviour of client-owned Siberian Huskies. Sixteen dogs were blocked for age, BW and sex and then randomly allocated to either the control or treatment group. Both groups were fed the same dry extruded diet; however, the treatment group were supplemented with tryptophan to achieve a tryptophan: large neutral amino acid ratio of 0.075:1. Once a week, a 5-minute video recording was taken immediately pre- and post- exercise to evaluate dogs' behaviours. Activity monitors were used to record voluntary activity on both training and rest days. Linear regression analysis was used to assess the relationship between training week and time spent performing each behaviour. Additionally, a repeated measure mixed model was used to test differences between diet groups and training week for both behavioural and activity count data. The time spent performing agonistic behaviours prior to exercise was negatively associated with week for treatment dogs (β = -0.32, 95% CI [-0.55, -0.10], P 0.10). Treatment did not have any effect on activity levels (P > 0.10). For all dogs, locomotive behaviours decreased prior to exercise as weeks progressed (P < 0.05), while run day voluntary activity depended on the distance run that day (P < 0.05). These data suggest that sled dogs experience an exercise-induced reduction in voluntary locomotion in response to both single bouts and repetitive bouts of exercise. Additionally, tryptophan supplementation may decrease agonistic behaviours, without having any effect on voluntary activity

The Behavioural Impact on Cats during a Transition from a Clay-Based Litter to a Plant-Based Litter

Current guidelines recommend transitioning cats from one litter product to another over 6 days to minimize stress. The study objective was therefore to test these guidelines using 16 adult domestic cats (2 cohorts of 8) by observing behavioural changes associated with elimination throughout the litter transition. Cats were transitioned from a clay-based litter (CLAY) to a plant-based litter product (PLANT) over 6 days (period 1) via an incremental replacement of CLAY with PLANT. All cats then remained on PLANT for 8 days (period 2). This same transition process was executed for both cohorts, and litter box behaviours were observed via remote recording. Urination, defecation, cover, and dig behaviours were not different between periods 1 and 2 (p > 0.05). Sniffing frequency was greater in period 2 than period 1 (p p < 0.05). These data suggest that 6 days may be an adequate amount of time to transition a cat to a new litter, although successful transition may also be specific to the types of litters investigated

“Undetectable, Now What?” HIV Provider Opinions on Barriers to Healthy Aging for Older People Living with HIV in North America

Background: People living with HIV (PLWH) experience age-associated health conditions earlier than their HIV-uninfected peers and have higher rates of co-occurring conditions that impact aging. Thus, HIV providers frequently confront issues related to HIV and aging. Objective: The objective of this project was to understand provider opinions about the care of older PLWH better. Design: This was accomplished using a quantitative survey. Participants: This study involved 681 physicians treating PLWH in North America. MAIN MEASURES: We collaborated with the Emerging Infections Network (EIN) to administer a ninequestion survey covering practice characteristics, attitudes, and perceived barriers in caring for older PLWH. Key Results: Two hundred and ninety-four (43.2%) responses were collected. Providers estimate that 35% (IQR: 25-50) of their HIV-infected patients were &gt;50 years. The majority (72%) agreed it is difficult to care for older PLWH but had confidence in their ability to do so (85%). Most list a lack of time (55.4%) and insufficient multidisciplinary support (58.5%) as limitations to the effective management of older PLWH. Multi-morbidity was overwhelmingly perceived as the most important barrier to healthy aging (62.2%) followed by tobacco/alcohol use (10%), low income/savings (8.2%), polypharmacy (4.8%) and mental illness (4.4%). Loneliness, frailty, and cognitive difficulties were judged to be less important. In conclusion, HIV providers recognized the complexity of caring for older PLWH, and yet were confident they could care for this population. Conclusion: Multi-morbidity was identified as a major barrier to healthy aging, while syndromes such as frailty and cognitive difficulties were deemed less important despite a growing body of evidence that these geriatric syndromes are common in older PLWH