Seasonal changes in energy economy of farmed polecat as evaluated by body weight, food intake and behavioural strategy

Korhonen, Hannu T.; Harri, Mikko

doi:10.1016/0031-9384(86)90184-8

Cited by 16 publications

(4 citation statements)

References 23 publications

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“…Thus, although the natural body condition of the European polecat is lean, it has the potential for extensive weight gain and obesity analogous to humans. The high fat-% (40%) of the farmed polecats probably results from excessive and prolonged positive energy balance (18) and limited physical activity (19,20)-crucial aspects in human obesity, as well. Artificial selection for a large body size (21) may also be a causative factor.…”

Section: Discussionmentioning

confidence: 99%

Response to Fasting in an Unnaturally Obese Carnivore, the Captive European Polecat Mustela putorius

Mustonen

Puukka²,

Rouvinen‐Watt³

et al. 2009

Exp Biol Med (Maywood)

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The European polecat (Mustela putorius) is a naturally lean carnivore prone to excessive weight gain in captivity. This study assessed its suitability to investigate the natural history of the obese phenotype displayed in overweight humans, domestic animals, and seasonally obese wild mammals. Ten farm-bred polecats were subjected to a 5-day fast with 10 controls. Obesity (40% body fat) was associated with an unfavorable plasma lipid profile and high glucose and insulin concentrations. The polecats were in phase II of fasting with normoglycemia, low liver carbohydrate stores, and decreased plasma concentrations of urea and most amino acids. Although the plasma nonesterified fatty acid (NEFA) levels were elevated, the adipose tissue lipase activities suggested a blunted lipolytic response. Lipid mobilization was more efficient from intraabdominal fat. The animals developed hepatic lipidosis with elevated NEFA influx into the liver and losses of n-3 polyunsaturated fatty acids and arginine as hypothetical etiological factors. The plasma leptin, insulin, and triiodothyronine levels decreased but were not accompanied by reduced sex steroid or increased stress hormone concentrations. The blunted lipolytic response often encountered in obesity suggests that the organism is trying to defend the obese phenotype. Liver lipidosis and decreased insulin and triiodothyronine levels seem to be among the most consistent responses to fasting manifested in diverse mammalian orders and different levels of body fatness. The polecat could be recommended as an easily accessible carnivorean model to study the natural history of the obese phenotype and its comorbidities.

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Section: Discussionmentioning

confidence: 99%

Response to Fasting in an Unnaturally Obese Carnivore, the Captive European Polecat Mustela putorius

Mustonen

Puukka²,

Rouvinen‐Watt³

et al. 2009

Exp Biol Med (Maywood)

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“…seasonal changes in body weight of farmed mink, Korhonen and Niemelä, 1998), a phenomenon also found in captive animals when fed ad libitum (e.g. Korhonen and Harri, 1986). Also, heavier foxes lost more weight than lighter ones, a finding that was most pronounced in the excessive fed foxes.…”

Section: Discussion Experimentsmentioning

confidence: 64%

Responses of farmed silver foxes (Vulpes vulpes) to excessive food availability: Implications for using food as a yardstick resource in motivation tests

Hovland

Mason

Ahlstrøm

et al. 2007

Applied Animal Behaviour Science

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Food is frequently used as a 'yardstick' in operant experiments. However, previous work on silver foxes had suggested that how food is presented can affect how they respond to it, with excess food leading to variable consumption rates, and cages containing food being avoided over control cages except while eating. Our first experiment therefore examined foxes' consumption of excess food in more detail by comparing their daily intakes with foxes fed a control diet for 4 weeks. Eighteen silver fox vixens were assigned to one of two groups in which the experimental group (N = 9) was feed 2.5 times that of control (N = 9). Although appetite, measured as the amount of food consumed, tended to fluctuate none of the overly fed foxes stopped eating during the experimental period. On average, the excessive fed group consumed more food (317 AE 18 g/day) compared to the controls (273 AE 12 g/day).In Experiment 2 we aimed to test whether the presence of excess food affected the foxes' use of the cage. Five silver fox males were housed in separate multi-compartment apparatuses and the position of a food bowl was randomly switched between two cages for 18 days. The subjects had to perform one operant response to enter each cage and time inside the compartments was calculated. The foxes spent significantly less time in the food compartment (4 h 13 min), compared to the empty cage (12 h 12 min) and as expected by random (8 h) (P < 0.05). These results confirm that ad libitum fed silver foxes have a more fluctuating intake rate than animals fed just below maintenance, and that placing food in a cage reduces the time spent there. The day-to-day use of food, and perhaps even its value, can therefore be shaped by how it is presented. Implications for using food as a yardstick resource for silver foxes is that the ration should be held at maintenance. Also, to control for a motivation to leave food positioned in the operant test cage a free control cage distant from food could be provided. #

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“…Seasonal weight changes have been observed in polecats and other closely related species such as mink. These weight changes are seen as adaptations to the differing energy intake and expenditure requirements of winter and summer [ 17 , 18 ]. In animal care facilities, daylight hours can be easily regulated and are often set at a 12-hour light cycle (12-hours ON, 12-hours OFF) or synchronised with the external environment; for example, varying from a minimum 8-hour cycle in winter (8-hours ON, 16-hours OFF) to maximum 16-hour cycle in summer (16-hours ON, 8-hours OFF) [ 19 – 22 ].…”

Section: Introductionmentioning

confidence: 99%

Seasonal weight changes in laboratory ferrets

et al. 2020

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Ferrets (Mustela putorius furo) are a valuable animal model used in biomedical research. Like many animals, ferrets undergo significant variation in body weight seasonally, affected by photoperiod, and these variations complicate the use weight as an indicator of health status. To overcome this requires a better understanding of these seasonal weight changes. We provide a normative weight data set for the female ferret accounting for seasonal changes, and also investigate the effect of fluid regulation on weight change. Female ferrets (n = 39) underwent behavioural testing from May 2017 to August 2019 and were weighed daily, while housed in an animal care facility with controlled light exposure. In the winter (October to March), animals experienced 10 hours of light and 14 hours of dark, while in summer (March to October), this contingency was reversed. Individual animals varied in their body weight from approximately 700 to 1200 g. However, weights fluctuated with light cycle, with animals losing weight in summer, and gaining weight in winter such that they fluctuated between approximately 80% and 120% of their long-term average. Ferrets were weighed as part of their health assessment while experiencing water regulation for behavioural training. Water regulation superimposed additional weight changes on these seasonal fluctuations, with weight loss during the 5-day water regulation period being greater in summer than winter. Analysing the data with a Generalised Linear Model confirmed that the percentage decrease in weight per week was relatively constant throughout the summer months, while the percentage increase in body weight per week in winter decreased through the season. Finally, we noted that the timing of oestrus was reliably triggered by the increase in day length in spring. These data establish a normative benchmark for seasonal weight variation in female ferrets that can be incorporated into the health assessment of an animal's condition.

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Seasonal changes in energy economy of farmed polecat as evaluated by body weight, food intake and behavioural strategy

Cited by 16 publications

References 23 publications

Response to Fasting in an Unnaturally Obese Carnivore, the Captive European Polecat Mustela putorius

Response to Fasting in an Unnaturally Obese Carnivore, the Captive European Polecat Mustela putorius

Responses of farmed silver foxes (Vulpes vulpes) to excessive food availability: Implications for using food as a yardstick resource in motivation tests

Seasonal weight changes in laboratory ferrets

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