Our goal was to trace the inclusion of poultry offal meal (OM) in diets by using carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N) isotopic ratios of different tissues in order to contribute for the development of an independent technology for the certification of the feeding of broilers reared on diets with no addition of animal ingredients. Eighty one-dayold chicks were randomly distributed into five experimental treatments, that is, diets containing increasing levels of OM inclusion (0, 2, 4, 8 and 16% OM), with four replicates of four birds each. At 42 days of age, four birds per treatment (n=4) were randomly selected, weighed, and sacrificed to collect breast muscle (Pectoralis major), keel and tibia samples to determine their isotopic ratios ( 13 C/ 12 C e 15 N/ 14 N). It was observed that 13 C and 15 N enrichment increased as a function of increasing OM inclusion in all diets. The analyses of the Pectoralis major showed that that only treatments with 8 and 16% OM dietary inclusion were different form those in the control group (0% OM). On the other hand, when the keel and tibia were analyzed, in addition to 8 and 16% OM), the treatment with 4% OM inclusion was also different from the control group. The use of isotopic ratios of stable carbon and nitrogen isotopes is an alternative to trace OM inclusion in broiler diets as it is capable of tracing OM levels below those usually practiced by the poultry industry in Brazil.

The present study aimed at evaluating the effect of the dietary inclusion of organic trace minerals selenium and zinc on the performance and internal and external egg quality of Japanese quails submitted to heat stress. Data on egg production, feed conversion (kg feed intake/ kg eggs and dozen eggs), egg weight, egg specific gravity, eggshell thickness and weight, Haugh unit, yolk index, albumen index and mortality (%) of 144 quails were evaluated for 112 days, divided in eight cycles of 14 days. Birds were distributed according to a randomized block experimental design into four treatments (control; 0.3ppm Se; 60ppm Zn and 0.3ppm Se + 60ppm Zn) with six replicates each. There were no differences (p > 0.05) in egg production (%), egg mass (g/hen/ day), feed conversion per egg mass (kg/kg), feed conversion per dozen eggs (kg/dz), average egg weight (g), egg specific gravity, eggshell thickness and weight (g), Haugh unit, yolk index, albumen index and mortality (%). However, quails fed the combination of Se and Zn presented higher (p < 0.05) feed intake (28.73 g/hen/day). Those fed only organic selenium had higher average daily egg production (30.17 eggs/day), and those fed the diet only supplemented with zinc presented higher mortality (p < 0.05). The results of the present study suggest that the supplementation of organic trace minerals in Japanese quails diets submitted to heat stress does not significantly influence quail performance and internal egg quality, whereas the supplementation of the combination of organic Zn and Se increases feed intake.

The 13C turnover rates of the liver and thoracic pectoral muscle of growing broilers were determined by feeding diets with varying 13C content. Male chicks (1-d-old) were subjected to treatments based on free choice of 5 different mixes of energy and protein sources from plants with C3 and C4 photosynthetic pathways that had differing 13C content. Rice bran (R) and soybean meal (S) were the C3 sources, while maize (C) and maize gluten meal (G) were the C4 sources. Choices were R + S, C + G, R + G, C + S or R + C + G + S. The 6th treatment was a complete feed (CF) that was similar to a commercial broiler feed. The isotopic composition of the birds' tissues was representative of the isotopic composition of the diets. The assimilation was faster for C3, in both liver and muscle, than for C4 diets, and give the delta per mil difference between the diet and tissues. The liver is the most active metabolic tissue and gave more rapid isotope turnover than in muscle.

Studies on the detection of animal by-products in poultry meat are rare and practically nonexistent in chicken meat. With the development of the technique of stable isotopes for traceability purposes and the certification of broiler diet patterns, it has been necessary to know the behavior of the isotopic signature of different tissues in birds, in case of a potential replacement of a diet containing animal ingredients with a strictly vegetable one and vice versa. Thus, this study, carried out at the São Paulo State University, Botucatu Campus, Brazil, aimed to evaluate meat from the breast, thigh, drumstick, and wings to trace the presence of poultry offal meal (OM) in broiler feed using the analysis of stable isotopes of carbon ((13)C/(12)C) and nitrogen ((15)N/(14)N) by mass spectrometry. In total, 720 one-d-old chicks were distributed into 6 groups: vegetable diet (VD) from 1 to 42 d; 8% poultry offal meal (OM) diet from 1 to 42 d; VD from 1 to 21 d and 8% OM diet from 22 to 42 d; VD from 1 to 35 d and 8% OM diet from 36 to 42 d; 8% OM diet from 1 to 21 d and VD from 22 to 42 d; and 8% OM diet from 1 to 35 d and VD from 36 to 42 d. Through the analysis of C and N, it is possible to trace the use of OM in broiler feeding when this ingredient is part of the feeding throughout the breeding phase or when it substitutes a strictly VD even up to 35 d. When an OM diet is substituted by a VD, the animal ingredient has to be part of the feeding for 21 d or longer to be detected by this method.