Trace mineral supplies for populations of little and large herbivores.

Copper (Cu), iron (Fe), and zinc (Zn) are essential trace minerals for the reproduction, growth, and immunity of mammalian herbivore populations. We examined the relationships between Cu, Fe, and Zn in soils, common plants, and hepatic stores of two wild herbivores to assess the effects of weather, sex, and population density on the transfer of trace minerals from soils to mammals during the growing season. Soils, grasses, woody browse, hispid cotton rats (Sigmodon hispidus), and white-tailed deer (Odocoileus virginianus) were sampled across 19 sites. Concentrations of Cu, Fe, and Zn in grasses and browse species were not correlated with concentrations of those minerals in soils sampled from the same areas. Leaves of woody browse were higher in Cu, lower in Fe, and similar in Zn when compared with grasses. Available concentrations of soils were positively related to liver Cu and Zn in hispid cotton rats, which was consistent with the short lives and high productivity of these small mammals that rely on grass seed heads. Interactions between soil concentrations and weather also affected liver Cu and Fe in deer, which reflected the greater complexity of trophic transfers in large, long-lived, browsing herbivores. Population density was correlated with liver concentrations of Cu, Fe, and Zn in hispid cotton rats, and concentrations of Cu and Fe in deer. Liver Cu was < 5 mg/kg wet weight in at least 5% of animals at two of eight sites for hispid cotton rats and < 3.8 mg/kg wet weight in at least 5% of animals at three of 12 sites for deer, which could indicate regional limitation of Cu for populations of mammalian herbivores. Our data indicate that supplies of trace minerals may contribute to density dependence of herbivore populations. Local population density may therefore influence the prevalence of deficiency states and disease outbreak that exacerbate population cycles in wild mammals.

The World Organisation for Animal Health and the World Health Organization: intergovernmental disease information and reporting systems and their role in early warning.

Only two international organisations have a global legal framework that allows them to request, collect, and release global animal or human health information: the World Organisation for Animal Health (OIE), which is responsible for transparently assessing the global animal health situation, and the World Health Organization (WHO), which is responsible for transparently assessing the global human health situation. Legal instruments bind OIE Member Countries and WHO States Parties (OIE's Standards and WHO's International Health Regulations [IHR]) to report certain disease outbreaks and public health events to their respective organisations. OIE Member Countries must report exceptional epidemiological events involving any OIE-listed diseases, including zoonoses. Moreover, they must notify the OIE of any emerging animal diseases. The IHR require WHO Member States to provide notification of events that may constitute a public health emergency of international concern. These include, but are not restricted to, outbreaks of communicable diseases of international concern. In both organisations, in addition to reporting outbreaks and exceptional events, Members also monitor diseases on an ongoing basis and provide regular reports. To complement these passive surveillance mechanisms, the OIE, WHO and the Food and Agriculture Organization of the United Nations track signals from informal sources of outbreaks of animal and zoonotic infectious diseases, thereby increasing the sensitivity of worldwide disease reporting. The formal information collected is disseminated to Members and the general public through various communication channels, so that countries can apply science-based measures to prevent further disease spread. Both the OIE and WHO reporting systems are supported by a range of coordinating activities to ensure the proper flow of information between national and international levels.

Deux organisations internationales seulement disposent d'un cadre juridique mondial permettant de demander, collecter et diffuser des informations sur la santé animale ou humaine dans le monde : il s'agit de l'Organisation mondiale de la santé animale (OIE), qui est chargée d'évaluer de manière transparente la situation zoosanitaire mondiale, et de l'Organisation mondiale de la santé (OMS), qui est chargée d'évaluer de manière transparente la situation de la santé humaine dans le monde. Ces deux organisations ont mis en place des instruments juridiques (les normes sanitaires de l'OIE et le Règlement sanitaire international [RSI] de l'OMS) qui imposent aux Pays membres de l'OIE et aux États parties au RSI de notifier tout événement sanitaire important à leurs organisations respectives. Les Pays Membres de l'OIE doivent notifier tout événement épidémiologique exceptionnel concernant les maladies de la liste de l'OIE, y compris les zoonoses. En outre, ils doivent notifier à l'OIE toute maladie animale émergente. Le RSI impose aux États membres de l'OMS de notifier tout événement pouvant constituer une urgence de santé publique de portée internationale. Cela couvre notamment les foyers de maladies transmissibles importantes au plan international. Outre le signalement des foyers et des événements exceptionnels, les Membres des deux organisations exercent également une surveillance de routine des maladies et communiquent des rapports réguliers. En complément de ces mécanismes de surveillance passive, l'OIE, l'OMS et l'Organisation des Nations Unies pour l'alimentation et l'agriculture (FAO) assurent le suivi de tout signalement provenant de sources non officielles concernant d'éventuels foyers de maladies animales infectieuses et zoonotiques, ce qui accroît la sensibilité du système de notification des maladies à l'échelle mondiale. Les informations recueillies par la voie officielle sont diffusées aux Pays membres et au grand public par divers canaux de communication afin que les pays puissent appliquer des mesures fondées sur la science et empêcher ainsi toute nouvelle propagation. Les systèmes de notification de l'OIE et de l'OMS s'appuient tous deux sur une série d'activités de coordination afin d'assurer la bonne circulation de l'information entre les niveaux national et international.

Solo dos organizaciones internacionales disponen de un mecanismo jurídico de alcance planetario que les permita solicitar, reunir y hacer pública información sanitaria o zoosanitaria de dimensión mundial: la Organización Mundial de Sanidad Animal (OIE), responsable de evaluar con transparencia la situación zoosanitaria del mundo; y la Organización Mundial de la Salud (OMS), que se encarga de evaluar con transparencia la situación mundial en materia de salud humana. Hay instrumentos jurídicos que obligan a los Países Miembros de la OIE y los Estados Miembros de la OMS a notificar a la organización correspondiente todo caso importante de enfermedad (las normas de la OIE, por un lado, y el Reglamento Sanitario Internacional de la OMS [RSI]), por el otro). Los Países Miembros de la OIE deben comunicar episodios epidemiológicos excepcionales en los que intervenga cualquiera de las enfermedades que figuran en la lista de la OIE, zoonosis inclusive. Además, deben notificar a la OIE la aparición de toda enfermedad animal emergente. El RSI obliga a los Estados Miembros de la OMS a notificar todo episodio que pueda constituir una emergencia de salud pública de importancia internacional, como pueden ser, por ejemplo, los brotes de enfermedades transmisibles de importancia internacional. Los Miembros de ambas organizaciones, además de comunicar brotes y episodios excepcionales, deben vigilar continuamente la presencia de enfermedades y presentar informes periódicos. Para complementar estos mecanismos de vigilancia pasiva, la OIE, la OMS y la Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO) siguen de cerca las señales procedentes de fuentes oficiosas que puedan indicar la presencia de brotes infecciosos de enfermedades animales o zoonóticas, con lo que acrecientan la sensibilidad del dispositivo mundial de notificación. La información oficial así obtenida transita por diversos canales de comunicación para llegar a los Países Miembros y el gran público, de forma que los países puedan adoptar medidas científicamente fundamentadas para evitar la ulterior propagación de los brotes. Los sistemas de notificación de la OIE y la OMS están respaldados por una serie de actividades de coordinación que aseguran la adecuada circulación de información entre los niveles nacional e internacional.

An overview of internet biosurveillance.

Internet biosurveillance utilizes unstructured data from diverse web-based sources to provide early warning and situational awareness of public health threats. The scope of source coverage ranges from local media in the vernacular to international media in widely read languages. Internet biosurveillance is a timely modality that is available to government and public health officials, healthcare workers, and the public and private sector, serving as a real-time complementary approach to traditional indicator-based public health disease surveillance methods. Internet biosurveillance also supports the broader activity of epidemic intelligence. This overview covers the current state of the field of Internet biosurveillance, and provides a perspective on the future of the field.

W135 invasive meningococcal infections imported from Sub-Saharan Africa to France, January to April 2012.

From January to April 2012, 16 cases of W135 invasive meningococcal infection were reported in France. Of these, eight were linked to a recent travel history to Sub-Saharan Africa. These cases were reported in France concomitantly with the meningitis epidemic season in Sub-Saharan Africa. Considering the high number of travellers between France and West-African countries belonging to the so-called meningitis belt, the French recommendations for travellers stress the importance of vaccination before travelling to these countries.

Glucocorticosteroid concentrations in feces and hair of captive caribou and reindeer following adrenocorticotropic hormone challenge.

Climate change and industrial development are contributing to synchronous declines in Rangifer populations across the Arctic. Chronic stress has been implicated as a proximate factor associated with decline in free-ranging populations, but its role in Rangifer is unspecified. Analysis of glucocorticosteroid (GC) concentration in feces, and more recently in hair, is a non-invasive method for monitoring stress in wildlife. Adrenocorticotropic hormone (ACTH) released from the pituitary gland stimulates GC release from the adrenals and can be administered to reflect adrenal activation. In this study, we assessed concentrations of GC metabolites in feces and cortisol in hair of Alaskan caribou (Rangifer tarandus granti) and reindeer (R. t. tarandus) following ACTH treatment. We predicted that ACTH challenge would increase concentrations of fecal GCs, but not hair cortisol because steroid deposited into the hair shaft occurs over an extended period of time (months) and is likely insensitive to acute adrenal stimulation. Adult caribou (n=10; mean age, 6.5 years old) exhibited a peak increase in fecal GCs 8h following a 2 IU/kg dose of ACTH compared to pre-injection concentrations. In contrast, sub-adult reindeer (n=10, 0.8 years old) elicited a diminished response to the same dose. Quadrupling the dose (8 IU/kg) prolonged the fecal GC response in female reindeer, but male reindeer were unresponsive. Hair cortisol was unaffected by a single ACTH challenge. Further investigation is required to ascertain whether subspecific differences in adrenal sensitivity are attributed to age or sex differences, or historical selective pressures from semi-domestication and/or sedentary life cycle in reindeer.

The influenza A(H5N1) epidemic at six and a half years: 500 notified human cases and more to come.

Since November 2003, the epidemic intelligence team at the French Institut de Veille Sanitaire has been gathering data on influenza A(H5N1) circulation in poultry and on human cases worldwide. As Indonesia notifies the world's 500th case to the World Health Organization, we discuss the epidemiological situation and trends of A(H5N1) influenza. Although the overall number of cases reported worldwide has decreased, influenza A(H5N1) continues to circulate intensely in some countries and more cases are to be expected, especially in Egypt and Indonesia.

Digestive challenges for vertebrate animals: microbial diversity, cardiorespiratory coupling, and dietary specialization.

The digestive system is the interface between the supply of food for an animal and the demand for energy and nutrients to maintain the body, to grow, and to reproduce. Digestive systems are not morphologically static but rather dynamically respond to changes in the physical and chemical characteristics of the diet and the level of food intake. In this article, we discuss three themes that affect the ability of an animal to alter digestive function in relation to novel substrates and changing food supply: (1) the fermentative digestion in herbivores, (2) the integration of cardiopulmonary and digestive functions, and (3) the evolution of dietary specialization. Herbivores consume, digest, and detoxify complex diets by using a wide variety of enzymes expressed by bacteria, predominantly in the phyla Firmicutes and Bacteroidetes. Carnivores, such as snakes that feed intermittently, sometimes process very large meals that require compensatory adjustments in blood flow, acid secretion, and regulation of acid-base homeostasis. Snakes and birds that specialize in simple diets of prey or nectar retain their ability to digest a wider selection of prey. The digestive system continues to be of interest to comparative physiologists because of its plasticity, both phenotypic and evolutionary, and because of its widespread integration with other physiological systems, including thermoregulation, circulation, ventilation, homeostasis, immunity, and reproduction.

The 2009 pandemic H1N1 influenza and indigenous populations of the Americas and the Pacific.

There are few structured data available to assess the risks associated with pandemic influenza A(H1N1)v infection according to ethnic groups. In countries of the Americas and the Pacific where these data are available, the attack rates are higher in indigenous populations, who also appear to be at approximately three to six-fold higher risk of developing severe disease and of dying. These observations may be associated with documented risk factors for severe disease and death associated with pandemic H1N1 influenza infection (especially the generally higher prevalence of diabetes, obesity, asthma, chronic obstructive pulmonary disease and pregnancy in indigenous populations). More speculative factors include those associated with the risk of infection (e.g. family size, crowding and poverty), differences in access to health services and, perhaps, genetic factors. Whatever the causes, this increased vulnerability of indigenous populations justify specific immediate actions in the control of the current pandemic including primary prevention (intensified hygiene promotion, chemoprophylaxis and vaccination) and secondary prevention (improved access to services and early treatment following symptoms onset) of severe pandemic H1N1 influenza infection.

Epidemiology of fatal cases associated with pandemic H1N1 influenza 2009.

This article describes the characteristics of 574 deaths associated with pandemic H1N1 influenza up to 16 July 2009. Data (except from Canada and Australia) suggest that the elderly may to some extent be protected from infection. There was underlying disease in at least half of the fatal cases. Two risk factors seem of particular importance: pregnancy and metabolic condition (including obesity which has not been considered as risk factor in previous pandemics or seasonal influenza).

Plague outbreak in the Libyan Arab Jamahiriya.

Plague is circulating regularly in localised areas worldwide, causing sporadic cases outside Africa and remains endemic or causes limited outbreaks in some African countries. Furthermore, some notable outbreaks have been reported in Asia in the last 20 years. A limited outbreak with five cases has recently been notified by the health authorities of the Libyan Arab Jamahiriya.

EpiSouth: a network for communicable disease control in the Mediterranean region and the Balkans.

The countries around the Mediterranean Sea share epidemiological characteristics and public health problems. In 2006 the EpiSouth Project was started as a framework for collaboration for communicable diseases surveillance and training in the Mediterranean Basin. As of December 2008, 26 countries from southern Europe, the Balkans, North Africa and the Middle-East are members of EpiSouth and several international organisations and institutions collaborate: the European Commission (EC), the European Centre for Disease Prevention and Control (ECDC), the Italian Ministry of Work, Health and Social Policies and the World Health Organization (WHO). The project is coordinated by the Italian national public health institute and three work packages (WPs) Cross-border epidemic intelligence, vaccine preventable diseases and migrants and Cross-border emerging zoonoses are operated by the national institutes of France, Bulgaria and Greece. These WPs constitute technical pillars on which the project develops. Networking and Training are WPs dedicated to capacity building and are run by the Padua Teaching Hospital (Italy) and the Spanish national public health institute. A steering committee guides EpiSouth's activities while all countries collaborate through WP steering teams and focal points. A number of outcomes have been accomplished and documents with results are available from the EpiSouth website which hosts a public website and a restricted area for direct sharing of information among the participants. Five electronic bulletins were published, two trainings for 63 participants performed, national epidemic intelligence systems were evaluated, a preliminary survey on vaccine-preventable diseases and migrants performed, and a list of priorities for emerging zoonoses in the Mediterranean area was selected. Overall the network succeeded in creating cohesion, mutual trust and concrete collaboration on cross-border public health issues in a geographical area that is not addressed as a whole by any other initiative or organisation.

[Emerging viral infections in South East Asia and the Pacific region]. / Viroses émergentes en Asie du Sud-Est et dans le Pacifique.

The epidemiology of several viral diseases underwent profound changes in South-East Asia and Oceania over the past decades. This was due to several factors, including the geographical distribution of vectors and the viruses they transmit; increasing traveling and trade; increasing ecological and demographic pressure. We reviewed the current state of knowledge based on published sources and available epidemiological data. The review was limited to potentially emerging viruses in Southeast Asia and the Pacific reported in human cases. Dengue, Chikungunya, and Japanese Encephalitis viruses have recurred on a yearly basis with a steady increase in these regions. Ross River and Barmah viruses now appear regularly in Australia, in an increasing number of cases. Nipah virus strikes regularly with limited but deadly epidemics in Southeast Asia. Finally, infections by lyssaviruses, Kunjin, Murray Valley, or Zika viruses were also reviewed.

Polygynous mating impairs body condition and homeostasis in male reindeer ( Rangifer tarandus tarandus).

Reindeer are polygynous ruminants that breed when plant growth declines in the Arctic. We studied seven males (2 years and older) in two herds with a total of 34 females to describe the costs and consequences of mating or rut. Body mass declined between September and November and did not recover through winter even though food was available ad libitum. Dominance did not affect body mass or any correlate of mass loss, indicating similar costs of rut among males. Males lost 34% of ingesta-free mass in 77 days of rut, which corresponded to depletion of 23% body protein and 78% body lipid. Water flux, plasma insulin, and plasma thyroxine were minimal 23 days after the peak in body mass, indicating low food intake. Maximum plasma testosterone and cortisol also followed peak mass and coincided with the death of two males from acute infections. Loss in body protein did not increase the ratio of urea to creatinine in plasma. Increased variance in plasma osmolality and urea during mass loss indicated altered homeostatic control during rut. Mating compromises survival of males through reduction of body reserves, food intake, and maintenance of tissues. These adverse effects may be the consequence of selection for large body size and aggression in a highly variable competition for mates.

Digestive constraints on an aquatic carnivore: effects of feeding frequency and prey composition on harbor seals.

We hypothesized that increased feeding frequency in captive harbor seals would increase nutrient loads and thus reduce retention time and the digestive efficiency of natural prey. We measured daily feed intake and excretion during 6 feeding trials and fed herring (49% lipid), pollock (22% lipid) or an equal mix of each diet over 24 months. Animals were accustomed to feeding at either high or low frequency. Body mass and intake did not vary with season. Although mean retention times were similar between diets and feeding frequencies, solute and particulate digesta markers separated at high feeding frequency. Consistent dry matter digestibility resulted in greater gut fill from pollock than from herring. Digestible energy intakes from pollock were approximately 25% greater than from either herring or the mixed diet. Lipid digestibility of herring declined from 90% to 50% when lipid intake exceeded 60 g kg(-0.75) day(-1). Our hypothesis of a trade-off between intake and digestion was not supported for protein but was supported for lipid. Results of this study imply that a flexible digestive system for harbor seals can compensate for ingesting prey of lower energy density by increasing gut fill and enhancing protein and lipid assimilation, to sustain digestible energy intake.

Intermittent fasting during winter and spring affects body composition and reproduction of a migratory duck.

We compared food intake, body mass and body composition of male and female black ducks (Anas rubripes) during winter (January-March). Birds were fed the same complete diet ad libitum on consecutive days each week without fasting (control; nine male; nine female) or with either short fasts (2 day x week(-1); nine male; nine female), or long fasts (4 day x week(-1); eleven male; twelve female). We continued treatments through spring (March-May) to measure the effect of intermittent fasts on body mass and egg production. Daily food intake of fasted birds was up to four times that of unfasted birds. Weekly food intake of males was similar among treatments (364 g x kg(-1) x week(-1)) but fasted females consumed more than unfasted females in January (363 g x kg(-1) x week(-1) vs. 225 g x kg(-1) x week(-1)). Although both sexes lost 10-14% body mass, fasted females lost less mass and lipid than unfasted females during winter. Total body nitrogen was conserved over winter in both sexes even though the heart and spleen lost mass while the reproductive tract and liver gained mass. Intermittent fasting increased liver, intestinal tissue and digesta mass of females but not of males. Fasting delayed egg production in spring but did not affect size, fertility or hatching of the clutch. Females on long fasts were still heavier than controls after laying eggs. Thus black ducks combine flexibility of food intake with plasticity of digestive tract, liver and adipose tissue when food supply is interrupted during winter. Females modulate body mass for survival and defer reproduction when food supply is interrupted in spring.

Surveillance of anti-tuberculosis drug resistance in Europe, 1999.

With the exception of Israel, representative data from Western and Central Europe indicate consistently low levels of resistance to isoniazid (0-9,3%) or rifampicin (0-2,1%) and of multidrug resistance (0-2,1%) among new tuberculosis (TB) cases. Resistance is more frequent among previously treated cases, but comparisons of data should be done cautiously, as criteria for inclusion in TB notifications may vary across countries. In Western Europe, drug resistance is more frequent among cases of foreign origin, a group with high TB incidence. In 1999, cases of foreign origin accounted for over 90% of the MDR cases in the West, and for all MDR cases notified in Israel. The majority of foreign born cases notified originated from Africa or Asia. In the East, representative data from the Baltic States show that overall, 15% of TB cases notified in 1999 were MDR, among the highest proportion worldwide and indicating inadequacies in previous treatment programmes. In the other countries of the former Soviet Union, non-representative data show high levels of resistance which, along with data from the Baltic states and results of surveys, are very alarming.

Mineral and heavy metal status as related to a mortality event and poor recruitment in a moose population in Alaska.

Moose (Alces alces) found dead (FD) and hunter-killed (HK) in 1995 on the north slope of Alaska (USA) in the Colville River Drainage were evaluated for heavy metal and mineral status. Compared to previous reports for moose and domestic cattle, and data presented here from Alaska moose outside the Colville River area, levels of Cu were determined to be low in hoof, hair, liver, kidney, rumen contents, and muscle for these north slope moose. Iron (Fe) was low in muscle as well. These findings, in conjunction with evidence of poor calf survival and adult mortality prompted investigation of a mineral deficiency in moose (serum, blood, and hair) captured in the spring of 1996 and 1997. Captured males had higher Ca, Zn and Cu levels in hair than captured females. Female moose hair samples were determined to be low (deficient) in Cu, Ca, Fe, and Se with mean levels (ppm) of 2.77, 599.7, 37.4, and 0.30, respectively. Serum Cu level was low, and to a lesser degree Zn was deficient as well. Whole blood (1997 only) was marginally deficient in Se and all animals were deficient in Cu. Based on whole blood, sera and hair, Cu levels were considered low for moose captured in spring 1996 and 1997 in the Colville River area as compared to published data and other populations evaluated in this study. Low levels of ceruloplasmin activity support this Cu deficiency theory. Evidence indicates that these moose are deficient in Cu and other minerals; however, the remote location precluded sufficient examination of animals to associate this apparent deficiency with direct effects or lesions. Renal levels of Cd increased with age at expected levels.

Ceruloplasmin as an indicator of copper reserves in wild ruminants at high latitudes.

Northern ungulates must establish trace mineral reserves when forage is available in spring and summer to sustain biochemical activities through the long winter. Copper (Cu), zinc (Zn) and iron (Fe) reserves were measured in the serum, digestive tract, liver, and kidney of six male caribou and reindeer (Rangifer tarandus) fed a complete pelleted ration. Dry matter content and absolute amounts of Cu, Zn and Fe were highest in the liver. Digesta contents of Cu and Zn were greatest in the rumen but dry matter concentrations were greatest in the cecum reflecting the high levels of Cu and Zn in the diet. Serum ceruloplasmin (an oxidase containing Cu) activity was related to liver copper in captive reindeer and caribou (P < 0.05, r2 = 0.82) during spring and winter but not during the rut. Michaelis-Menten kinetics of ceruloplasmin were measured in sera from captive reindeer, muskox (Ovibos moschatus) and moose (Alces alces) (n = 3/species). Maximum velocities (VMAX) were 42, 20 and 9 (IU x L(-1)); kM were 0.38, 0.55 and 0.62 (mM) for muskox, reindeer and moose respectively. Wild caribou (n = 3) from the Teshekpuk herd and moose (n = 3) from the Colville River had lower VMAX (7 IU x L(-1)) and higher km (1.9 mM) than their captive conspecifics. These kinetic parameters probably reflect differences in ceruloplasmin structure between species as well as differences in tissue reserves between populations within each species. Serum ceruloplasmin activity and kinetics can provide a non-lethal alternative to direct measures of hepatic Cu reserves in wild and captive populations. However, the method requires validation for the effects of sex, season, development and disease in each species.

Anatomy and development of the koala, Phascolarctos cinereus: an evolutionary perspective on the superfamily Vombatoidea.

Fifteen koalas (Phascolarctos cinereus)--5 pouched young from 4 to 6.5 months and 10 adults from 5 to 16.5 years--were analyzed for functional parameters (body composition, limb segment and muscle mass, post-cranial skeletal characters) and developmental expressions (growth of body, brain, musculature). These data were compared with a convergent eutherian, the three-toed sloth, Bradypus infuscatus, and with the koala's distant (Macropodid; wallabies) and proximate (Vombatid; wombats) marsupial relatives. Musculoskeletal structures correlated with sitting and climbing; the growth of the young and the physiological demands of adulthood correlated with the low-quality diet of Eucalyptus foliage. The gestalt of the ancestral Vombatoids (pronograde quadrupeds, generalist browsers and social conservatives with low basal metabolism and attenuated development) provided the baseline essential for their locomotor and nutritional divergence into arboreal browsers, the koalas, and fossorial grazers, the wombats.

Intermittent feeding in a migratory omnivore: digestion and body composition of American black duck during autumn.

Birds fast intermittently during weather disturbances and migration. We tested responses of black duck to lost feeding days during autumn mass gain. Nine adult males were fed a pelleted diet (1.5% fat, 15.8% protein, and 18.3% neutral detergent fiber) and caged indoors during September and October (12 h light; 17 degrees -24 degrees C) to measure balances over 14 d when fed ad lib. each day and fasted intermittently for 2 d wk(-1) (short fast) or 4 d wk(-1) (long fast). Body mass (1,081 g), body water content, and metabolizable intakes of energy and protein were maintained as daily intakes of dry matter increased to 1.65 (short fast) and 2.35 (long fast) times the unfasted level. Intermittent feeding reduced metabolizability of dry matter, energy, protein, and acid detergent fiber. Concentrations of Mn provided similar estimates of metabolizability to direct measures in unfasted birds but underestimated measures of birds on long fasts. Fasting regimes continued outdoors for 9 wk when temperatures declined to -9 degrees C. Birds on short fasts were heavier (1,373 vs. 1,241 g) and fatter (159 vs. 58 g) than those on long fasts, while body water (894 g) and protein (316 g) were similar between groups after 5 wk. Birds on long fasts subsequently gained mass when fed daily, but those on short fasts lost mass when fed each day. Omnivorous waterfowl combine ingestive and digestive flexibility with plasticity of body lipid to contend with uncertain food availability.