Thrifty development: Early-life diet restriction reduces oxidative damage during later growth

Abstract

1.Conditions during early stages of life may have an important effect on phenotype, by inducing programmed responses that may remain throughout the lifetime of an animal. One very important factor that can promote long-term changes in phenotype is restriction of food intake (dietary restriction, DR). 2.Recently, it has been shown that DR may induce an increase in antioxidant and repair mechanisms as a result of hormetic responses. Interestingly, the induction of antioxidant and repair mechanisms may be triggered by transitory increases in reactive oxygen species. Dietary-derived antioxidants, such as vitamin E, may be important to determine the compensatory effect of DR. 3.To investigate the effect of DR on attenuation of oxidative damage, we manipulated dietary intake (by restricting food ingestion) and antioxidant availability (by vitamin E supplementation) during the first days of life of yellow-legged gull (Larus michahellis) chicks. We then measured oxidative status and body mass during the early development of chicks. 4.We found that an early short event of food shortage strongly affected the oxidative status of the chicks and their growth patterns. We observed less oxidative damage to proteins and DNA in dietary restricted chicks, after the period of food restriction, than in non-restricted chicks. Unexpectedly, vitamin E supplementation did not suppress the hormetic effect of DR, but instead increased it. 5.These novel results support the idea that short events of DR during early development induce a reduction in oxidative damage in wild animals. The results suggest that DR promotes the induction of an early hormetic response in some antioxidant defence processes and/or repair mechanisms. These findings have important implications for our understanding of how early conditions may shape the phenotype of an organism, and also for the study of evolutionary trade-offs during early growth.