The stable carbon isotopes used in ecology and paleoecology during the last 30 years has now been used in dietary studies of animals. However, there are not enough studies on the metabolism patterns and turnover rates of the 13C in avian. This experiment established the turnover rates of the 13C in egg and liver tissues of adult laying hens through the substitution of commercial diets by diets containing C3 and C4 photosynthetic cycle grains for 50 days. The delta‰13C difference in two diets contents was 16.13‰. The diets 13C turnover rates in tissues were adapted in an exponential model that describes the isotopic carbon turnover in those tissues. Avian turnover rates of 13C fed with diet based on grains C3 were larger in liver than egg with half-life of 2.9 and 3.7 days. Avian fed with diet based on grains C4 showed turnover rates larger in egg than liver, with half-life of 4.0 to 5.3 days respectively. The delta‰13C values reached in egg and liver differed of the diet in approximately 2‰.
carbon-3; carbon-4; isotopic fractionation; nutritional metabolism; stable isotopes
