Turnover do δ13C na substituição de dietas com ingredientes de diferentes ciclos fotossintéticos em ovos de codornas japonesas (Coturnix coturnix japonica)

The study aimed to evaluate the turnover of 13C by replacing the C3 photosynthetic pathway diet to C4 and C4 to C3 in eggs of japanese quail (Coturnix coturnix japonica) using the technique of stable isotopes. Two hundred and sixteen japanese quail, 50 days old, distributed in a completely randomized experimental design with two treatments in six replications, in an experimental period of 48 days, were used. Prior to 50 days of age, half of quails consumed diet based on C4 plants (corn) and the other half based on C3 plants (rice), both containing meat meal and bone meal. There was replacement of those diets during the experimental period,  C3 based diet to C4 and C4 to  C3. A total of six eggs were collected from each treatment per day, according the quails age: 50, 51, 52, 54, 57, 60, 64, 68, 73, 78, 85, 91 and 98 days. To determine the turnover rate, the exponential model of isotopic dilution was employed. The experimental time of 48 days was enough for the total turnover in the eggs, with the incorporation of 99% of the carbon atoms of the new diet. The incorporation speed was slower when replacing diets were from C3 to C4 than C4 to  C3, which can be explained by bromatological differences of the ingredients.