Value verification isotopic from cheese made with dairy cows milk fed with poultry litter

The objective was to verify the occurrence of differentiation in the nitrogen isotopic value (?15N) between cheeses from cows with diets based on plant and based on poultry litter. The study was approved by MAPA of its execution (process 21052.009187 / 2013-02), and conducted in FMVZ, UNESP, Botucatu, with 12 dairy cows in milk, distributed in a completely randomized design with two treatments: T1 - Diet Vegetable; and T2 - poultry litter, with six animals per treatment and the experimental period was 90 days. The experimental diets were based on NRC (2001), isoproteic and isocaloric with 14% CP and 67% TDN. The diets were T1: corn silage, silage moist grain and soybean meal; and T2: poultry litter, corn silage and silage moist grain. For isotopic analysis were collected 1.5 liters of milk per cow for the production of cheese frescal, made according BONASSI (1999), and two measures: the first on 56 and the second on 91, a total of 24 cheeses. The treatment 2 received diet T2 until day 56, after this period the animals received T1, for 35 days. The isotopic measurements were determined in Stable Isotope Center IBB, UNESP, Botucatu. The data were analyzed jointly by multivariate analysis (MANOVA) complemented by principal component analysis in Minitab 16 (2010). It was observed that until 56 days of feeding animals receiving diet with poultry litter had the isotopic signal to nitrogen similar to the value of the diet (?15N diet = 10.5 ? and ?15N cheese = 10.5 ?), and when it was removed the poultry litter supply and supplemented with diet based on vegetables, the signal for nitrogen in cheese from cows returned to diet signal vegetable based (?15N diet = 3.0 ? and ?15N cheese 5.83 ? in 91 days), demonstrating that the animal is what it consumes and this is according to the turnover of the tissues and organs will incorporate in time and different speeds. In this case, it indicates that as animals were fed with different diets, signals will be reflected in the final product. The poultry litter when administered to lactating cows was detected by nitrogen isotopes and when removed from its supply, after 35 days the isotopic signal was not detected over the same milk. The tool of stable isotopes can be used as a support traceability of food origin of cattle.