L.G. Gaya et al. 760 Genetics and Molecular Research 4 (4): 760-764 (2005) www.funpecrp.com.br Genetic trends of abdominal fat content in a male broiler chicken line Leila de Genova Gaya 1 , Gerson Barreto Mourão 1 , Fernanda Marcondes de Rezende 1 , Elisângela Chicaroni de Mattos 1 , Tércio Michelan Filho 2 , Luís Gustavo Girardi Figueiredo 1 , José Bento Sterman Ferraz 1 and Joanir Pereira Eler 1 1 Grupo de Melhoramento Animal, Departamento de Ciências Básicas, Faculdade de Zootecnia e Engenharia de Alimentos, Pirassununga, SP, Brasil 2 Agroceres Ross Melhoramento Genético de Aves S.A., Rio Claro, SP, Brasil Corresponding author: L.G. Gaya E-mail: genova@usp.br Genet. Mol. Res. 4 (4): 760-764 (2005) Received December 9, 2004 Accepted April 29, 2005 Published December 15, 2005 ABSTRACT. Data of chickens from a broiler-breeding program were collected and used to determine the genetic trends of absolute and rela- tive abdominal fat content. The genetic trends were estimated by the regression of trait genetic value averages on hatch-years. Genetic val- ues from 32,485 individuals were used for regression analysis. The ge- netic trend estimate for absolute abdominal fat content was +0.39 g per year, indicating that abdominal fat deposition in the analyzed line, in ab- solute terms, tended to increase, making the existing excess fat deposi- tion in the broilers even worse. However, the genetic trend of relative abdominal fat content was not significant, indicating that there is no in- crease on abdominal fat content when it is corrected for body weight. Key words: Abdominal fat, Animal breeding, Broilers, Genetic value, Genetic trend Genetics and Molecular Research 4 (4): 760-764 (2005) FUNPEC-RP www.funpecrp.com.br