Differences in advanced glycation endproducts (AGEs) in plasma from birds and mammals of different body sizes and ages.

Birds and mammals provide a physiological paradox: similar-sized mammals live shorter lives than birds; yet, birds have higher blood glucose concentrations than mammals, and higher basal metabolic rates. We have previously shown that oxidative stress patterns between mammals and birds differ, so that birds, generally, have lower blood antioxidant capacity, and lower lipid peroxidation concentration. There is a close association between oxidative stress and the production of carbohydrate-based damaged biomolecules, Advanced Glycation End-products (AGEs).

Dietary vitamin E reaches the mitochondria in the flight muscle of zebra finches but only if they exercise.

Whether dietary antioxidants are effective for alleviating oxidative costs associated with energy-demanding life events first requires they are successfully absorbed in the digestive tract and transported to sites associated with reactive species production (e.g. the mitochondria).

Acute effects of intense exercise on the antioxidant system in birds: does exercise training help?

The acute effects of an energy-intensive activity such as exercise may alter an animal's redox homeostasis, although these short-term effects may be ameliorated by chronic exposure to that activity, or training, over time. Although well documented in mammals, how energy-intensive training affects the antioxidant system and damage by reactive species has not been investigated fully in flight-trained birds. We examined changes to redox homeostasis in zebra finches exposed to energy-intensive activity (60 min of perch-to-perch flights twice a day), and how exercise training over many weeks affected this response.

Dynamics of Individual Fatty Acids in Muscle Fat Stores and Membranes of a Songbird and Its Functional and Ecological Importance.

Although tissue fatty acid (FA) composition has been linked to whole-animal performance (e.g., aerobic endurance, metabolic rate, postexercise recovery) in a wide range of animal taxa, we do not adequately understand the pace of changes in FA composition and its implications for the ecology of animals.

Turnover of muscle lipids and response to exercise differ between neutral and polar fractions in a model songbird, the zebra finch.

The turnover rates of tissues and their constituent molecules give us insights into animals' physiological demands and their functional flexibility over time. Thus far, most studies of this kind have focused on protein turnover, and few have considered lipid turnover despite an increasing appreciation of the functional diversity of this class of molecules. We measured the turnover rates of neutral and polar lipids from the pectoralis muscles of a model songbird, the zebra finch (, =65), in a 256 day C/C diet shift experiment, with tissue samples taken at 10 time points.

The role of the antioxidant system during intense endurance exercise: lessons from migrating birds.

During migration, birds substantially increase their metabolic rate and burn fats as fuel and yet somehow avoid succumbing to overwhelming oxidative damage. The physiological means by which vertebrates such as migrating birds can counteract an increased production of reactive species (RS) are rather limited: they can upregulate their endogenous antioxidant system and/or consume dietary antioxidants (prophylactically or therapeutically). Thus, birds can alter different components of their antioxidant system to respond to the demands of long-duration flights, but much remains to be discovered about the complexities of RS production and antioxidant protection throughout migration.

The metabolic rate of cultured muscle cells from hybrid Coturnix quail is intermediate to that of muscle cells from fast-growing and slow-growing Coturnix quail.

Growth rate is a fundamental parameter of an organism's life history and varies 30-fold across bird species. To explore how whole-organism growth rate and the metabolic rate of cultured muscle cells are connected, two lines of Japanese quail (Coturnix coturnix japonica), one that had been artificially selected for fast growth for over 60 generations and a control line were used to culture myoblasts. In line with previous work, myoblasts from the fast growth line had significantly higher rates of oxygen consumption, glycolytic flux, and higher mitochondrial volume than myoblasts from the control line, indicating that an increase in growth rate is associated with a concomitant increase in cellular metabolic rates and that mitochondrial density contributes to the differences in rates of metabolism between the lines.

Physiological underpinnings associated with differences in pace of life and metabolic rate in north temperate and neotropical birds.

Animal life-history traits fall within limited ecological space with animals that have high reproductive rates having short lives, a continuum referred to as a "slow-fast" life-history axis. Animals of the same body mass at the slow end of the life-history continuum are characterized by low annual reproductive output and low mortality rate, such as is found in many tropical birds, whereas at the fast end, rates of reproduction and mortality are high, as in temperate birds. These differences in life-history traits are thought to result from trade-offs between investment in reproduction or self-maintenance as mediated by the biotic and abiotic environment.

Cellular metabolic rates in cultured primary dermal fibroblasts and myoblast cells from fast-growing and control Coturnix quail.

Fibroblast cells have been extensively used in research, including in medicine, physiology, physiological-ecology, and conservation biology. However, whether the physiology of fibroblasts reflects the physiology of other cell types in the same animal is unknown. Dermal fibroblasts are responsible for generating connective tissue and involved in wound healing, but generally, this cell type is thought to be metabolically inactive until it is required at the site of tissue damage.