Effects of fasting and refeeding on the antioxidant system in cockerels and pullets

Abstract

The effect of fasting and refeeding on total antioxidant status (TAS), glutathione peroxidase (GSH-Px) activity and concentration of some non-enzymatic antioxidant compounds was studied in cockerels and pullets. Blood was collected before and after 48-h fasting and 24 h after refeeding. In cockerels, fasting resulted in a significant decrease of TAS and uric acid concentration. After refeeding, the concentration of TAS remained significantly lower as compared to the control level. At the same time, blood plasma level of total lipids increased in comparison to the control and post-fasting values. In pullets, fasting resulted in a significant decrease of whole blood haemolysate GSH-Px activity and blood plasma concentrations of albumin and uric acid. Simultaneously, a significant increase in total lipids and cholesterol was obtained. In pullets, refeeding resulted in a further decrease of TAS to undetectable values, a significant decrease of blood plasma cholesterol, and a significant increase of GSH-Px in the whole blood haemolysate and in blood plasma uric acid content. The results indicate that fasting has a negative impact on the antioxidant defence system of the blood, which leads to a reduced resistance to oxidative stress in both cockerels and pullets. However, pullets seem to be more susceptible to fasting-provoked oxidative stress than cockerels.Key words: Antioxidant system, cockerel, pullet, fasting, refeeding Reactive oxygen compounds are produced continuously in most living organisms as a consequence of normal metabolic processes. Aerobic organisms,

Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins

“…The reduction in catalase activity observed in fasted penguins indeed indicates a reduction in the need for antioxidant protection, thus supporting this interpretation. This is reinforced by a previous study which reported that 48-h fasting considerably reduces the antioxidant defenses in the blood of cockerels and pullets (41).…”

Patterns of variation of serum oxidative stress markers in two seabird species

“…These birds experience five or six long fasting periods during each breeding season, which could increase oxidative stress and, possibly, reduce their fitness. Recent studies on birds suggest that fasting has a negative impact on the oxidative state (Milinkovic‐Tur et al. 2007; Rey et al.…”

Effect of a natural versus a synthetic antioxidant, and sex and age on the redox profile in the blood of growing turkeys

“…In turn, analyses of the other antioxidative parameters in the blood of the turkeys (FRAP, vitamin C, GSSG+GSH, H 2 O 2 ) demonstrated an initial increase until the 12th week of life, followed by a decrease in the 15th week. Investigations carried out with poultry, laboratory animals and humans have demonstrated that the activity of the antioxidative system, to some extent, is determined by age (Wang et al, 1998;Wickens, 2001;Milinković-Tur et al, 2007;Milinković-Tur et al, 2009). It has been proven that reactive oxygen species that induce cell damage and severe depletion of antioxidative defence elements accumulate in the course of body ageing (Sohal, 2002).…”

“…According to observations made in experiments with poultry and humans, the reducing level of FRAP along with age is an effect of depletion of non-enzymatic antioxidants, which are FRAP constituents (glutathione in particular) (Ibrahim et al, 2000;Milinković-Tur et al, 2007;Milinković-Tur et al, 2009). Results in the present study, viz.…”

“…The efficacy of antioxidative defence mechanisms is not a constant function, as it may be affected by the sex and age of the animal (Wang et al, 1998;Wickens, 2001;Milinković-Tur et al, 2007;Farahat et al, 2008b;Milinković-Tur et al, 2009). Modulation of the antioxidative status of the bird's body through specified treatments, including optimizing the level and quality of the diet, and selecting nutrients and functional components, may be one of the key and highly effective means of improving the efficiency of the antioxidative system and, thereby, the health status of poultry.…”