In the defence against hyperglycaemia: an avian strategy

Klandorf, H.; Probert, I.L.; Iqbal, Muhammad Kashif

doi:10.1079/wps19990019

Cited by 41 publications

(18 citation statements)

References 97 publications

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“…In birds, flight can increase the protein catabolism of muscle fibres (Bordel and Haase, 2000;Jenni et al, 2000;McWilliams et al, 2004), which in turn influences the production of uric acid, a waste product of nitrogen metabolism. However, uric acid is also well known to have antioxidant properties Klandorf et al, 1999;Tsahar et al, 2006). It could be that in the HF birds, the plasma concentration of uric acid did not decrease over the trials as it did in the CF (and to a lesser extent MF) birds, because it was…”

Section: Discussionmentioning

confidence: 98%

Loss of integration is associated with reduced resistance to oxidative stress

Costantini

Monaghan

Metcalfe

2013

Journal of Experimental Biology

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SUMMARYOne cellular mechanism thought to be particularly important as a constraint on lifespan and life-history strategies is oxidative stress. Susceptibility to oxidative stress is influenced by a number of antioxidant defences, whose effectiveness depends on the synergistic and competitive interactions among them (biochemical integration). It is generally assumed that exposure to oxidative stress is detrimental, but it is also possible that low level oxidative stress has a positive effect on integration, and therefore carries some benefits. Using three experimental groups of zebra finches (control, mild and high flight activity), we tested whether exercise-induced oxidative stress altered the integration of the pro-oxidant/antioxidant system by manipulating levels of flight activity, known to generate oxidative stress in birds. We show for the first time that a short-term high level of physical activity leads to a reduction in integration among components of the blood antioxidant defences, associated with a reduced resistance to oxidative stress. We found no evidence of improved integration in the antioxidant defences at low levels of oxidative stress exposure, suggesting that improved integration is not the route whereby any benefits of low level stress exposure occur. These findings point to a reduction in biochemical integration as a potential mechanism explaining a reduced resistance to oxidative stress induced by short-term stressors. Supplementary material available online at

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Section: Discussionmentioning

confidence: 98%

Loss of integration is associated with reduced resistance to oxidative stress

Costantini

Monaghan

Metcalfe

2013

Journal of Experimental Biology

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“…The main purpose of the present study was to determine from the first day after hatching the effect of 30‐day dietary cadmium exposure to chicken small intestine. Chicken are especially useful in biological studies due to their high intensity of some metabolic processes [24]. Over the last 15 years, chicken have been used extensively as monitors for pollutants.…”

Section: Discussionmentioning

confidence: 99%

Cadmium‐Induced Enteropathy in Domestic Cocks: A Biochemical and Histological Study after Subchronic Exposure

Berzina

Markovs²,

Isajevs

et al. 2007

Basic Clin Pharma Tox

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Abstract:The biochemical and histological sequelae resulting from a diet containing 50.20 mg cadmium/kg were studied in Lohmann brown cockerels from hatching until 30 days of age. The additional cadmium chloride (CdCl 2 ) to the diet induced the formation of lipid peroxides, which via a chain reaction led to accumulation of malondialdehyde in intestinal mucosa. At the end of the study (after 30 days of cadmium exposure) total protein and metallothionein levels in the intestinal mucosa and the relative ileal and duodenal weight increased. Histological data show that CdCl 2 causes an increase in number of goblet cells and granular lymphocytes in the intestinal mucosa. Down-regulation of the serotonin-positive cells in the cadmium-treated animals was observed. Growth retardation (by 27%) occurred in chicken fed the cadmium-enriched diet for 30 days. Cadmium accumulation in the intestine was markedly higher (154 times) in the cadmium-treated animals compared to the control group. Cadmium induced a decrease in zinc (but not copper) content in intestinal mucosa. We suggest that cadmium uptake triggers an inflammatory and secretory response in chicken small intestine.

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“…In humans, chronic levels of uric acid greater than about 0.4 mM cause gout (Pittman and Bross 1999), and values in most mammals (<0.01 mM) are much lower than in birds (Johnson and Rideout 2004). Uric acid is a potent scavenger of oxidants, and it has been proposed that uricotelism in birds could contribute to low ROS levels (Klandorf et al 1999). Diet manipulation studies in chickens have shown that plasma uric acid concentration is inversely correlated with cellular oxidation activity (Simoyi et al 2002), leading the authors to suggest that uric acid could have an important anti-aging role in birds.…”

Section: Antioxidantsmentioning

confidence: 98%

Avian senescence: underlying mechanisms

2007

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Candidate mechanisms for physiological aging include free radical production and resulting oxidative damage, progressive erosion of telomeres and cellular senescence, age-dependent trade-offs in hormone signaling pathways, and immunosenescence, leading to an increased risk of infection, autoimmune disease, and cancer. These mechanisms are inter-related, not mutually exclusive, and probably all contribute to the aging phenotype. To date, most studies on mechanisms of aging are based on cell culture or lab animals, but interest in comparative studies is growing rapidly. Compared to mammals, birds have long life spans for their body sizes. Birds also appear to have lower rates of free radical production and oxidative damage than mammals, despite higher levels of oxidative metabolism. High levels of the antioxidant, uric acid, in birds may help protect against oxidative damage. Cultured bird cells are more resistant to oxidative damage than mammal cells, and membrane phospholipids of birds are less susceptible to peroxidation than those of mammals of the same size, but show a similar susceptibility as those of mammals with the same life span. In birds, telomeres shorten with age, and the rate of shortening is proportional to life span. Telomerase has a higher activity in long-lived than in short-lived species. Within a species, short telomeres correlate with reduced survival. Birds have higher plasma glucose than mammals, but lower levels of protein glycation, which contributes to aging damage. Immunosenescence is linked to both oxidative damage and telomere shortening. Patterns of cellular and humoral immunosenescence differ among species in birds. The rate of decline in cell-mediated immune function is inversely correlated with life span. Comparative studies on mechanisms underlying senescence in birds will continue to provide us with valuable information on how aging mechanisms have evolved.

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In the defence against hyperglycaemia: an avian strategy

Cited by 41 publications

References 97 publications

Loss of integration is associated with reduced resistance to oxidative stress

Loss of integration is associated with reduced resistance to oxidative stress

Cadmium‐Induced Enteropathy in Domestic Cocks: A Biochemical and Histological Study after Subchronic Exposure

Avian senescence: underlying mechanisms

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