Abstract Objective: To review the technical aspects of body composition assessment by dual-energy X-ray absorptiometry (DXA) and other methods based on the most recent scientific evidence. Materials and methods: This Official Position is a result of efforts by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism (Associação Brasileira de Avaliação Óssea e Osteometabolismo, ABRASSO) and health care professionals with expertise in body composition assessment who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications. In this first part of the Official Position, the authors discuss the different methods and parameters used for body composition assessment, general principles of DXA, and aspects of the acquisition and analysis of DXA scans. Conclusion: Considering aspects of accuracy, precision, cost, duration, and ability to evaluate all three compartments, DXA is considered the gold-standard method for body composition assessment, particularly for the evaluation of fat mass. In order to ensure reliable, adequate, and reproducible DXA reports, great attention is required regarding quality control procedures, preparation, removal of external artifacts, imaging acquisition, and data analysis and interpretation.

ABSTRACT This study aimed to define management zones (MZs) for fertirrigated açaí cultivation, based on spatial variability of the foliar nutrients and productivity data. The work was carried out in an area of 5.75 ha of a 7-year crop, with 80 georeferenced sample points. Fresh fruit productivity and nutrient (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, and Zn) contents were determined. The average contents of macronutrients were considered adequate for adult açaí plants, and their spatial dependence associated with fruit productivity allowed the representation of their distributions through maps of variability. Through multivariate analysis, three main components were highlighted. These components explained 51.5 % of the total variability of the data, where PC1 showed a higher correlation with Ca, Mg, K, and P. In addition, three MZs were obtained, out of which one with the highest productivity showed the best Ca, Mg, S, B, and Fe leaf contents. Principal component analysis and determination of MZs emphasized Ca and Mg nutrition as being more related to spatial variability and açaí fruit productivity.

O efeito da substituição dos antimicrobianos (A) pelo ovo desidratado (OD) na ração e do tipo de cama (nova ou reciclada) usada na cobertura do piso sobre o desempenho de pintainhas de dois grupos genéticos foi avaliado em 1.440 aves de 1 dia de idade (720 de cada linhagem - leve e semipesada), distribuídas em 72 boxes de 1 x 1,5 m. A cama reciclada consistiu de bagaço de cana contaminado com excretas de frangos com sintomas de coccidiose. As pintainhas foram pesadas e distribuídas em um delineamento inteiramente ao acaso, em arranjo fatorial 3 x 2 x 2 (três rações x duas camas x duas linhagens), totalizando 12 tratamentos, cada um com seis repetições de 20 aves. As rações, formuladas com doses comerciais de antimicrobianos (R1), sem antimicrobianos (R2) ou sem antimicrobianos + 0,6% de OD (R3), foram fornecidas à vontade até os 7 dias de idade. O ovo desidratado foi composto de gema e albúmem desidratados a 55°C durante 72 horas e apresentou resultado negativo para Salmonella spp. O uso da cama reciclada afetou o desempenho das pintainhas dos dois grupos genéticos, especialmente das semipesadas, que apresentaram também menores pesos de baço e da bolsa de Fabricius, sugerindo atrofia de tecidos linfóides, o que provavelmente explica a menor tolerância dessas aves ao ambiente com cama reciclada. Os antimicrobianos atenuaram o efeito redutor do ambiente com cama reciclada sobre o desempenho das aves. O fornecimento de ovo desidratado é uma boa alternativa aos antimicrobianos e pode melhorar o desempenho de aves na fase pré-inicial criadas em ambiente convencional.

The effect of antimicrobial (A) replacement with dehydrated egg (DE) and of type of litter (new and recycled) used in the floor covering on pullet performance was evaluated in 1,440 1-d chicks, 720 of each strain (White and Brown), allotted to 72 boxes (1 x 1.5 m). Recycled litter consisted of sugar cane bagasse containing droppings of broilers chicks with symptoms of coccidiose. The pullets were weighed and assigned to a complete randomized design with a 3 x 2 x 2 (three diets x two litter x two strains) factorial arrangement, in a total of 12 treatments with six replications of 20 pullets. The experimental diets (D) were: D1 = diet with commercial dose of antimicrobial; D2 = diet without antimicrobial; and D3 = diet without antimicrobial + 0.6% of DE. DE was composed by dehydrated yolk+albumen (55°C for 72 hours) and showed negative result to Samonella spp. test. The use of recycled litter decreased pullet performance of two genetic groups, specially the Brown ones, that showed lower weights of spleen and bursa of Fabricius. This fact suggests better enlargement of lymphoid tissues, and that probably explains the smaller tolerance of White pullets to recycled litter. The antimicrobials minimize negative effect of recycled litter on pullet performance. Dehydrated egg is a good alternative to antimicrobials and can improve performance of pullets in the pre-starter on conventional environment.