Relationships between individual digestion efficiencies and gut anatomy in broilers from experimental D+ and D Disgestion lines or from commercial strains

Calculations were performed using a combination of data from 5 previous studies conducted in broilers from the experimental D+ and D- Digestion lines (n=432) observed during their selection process on 3rd, Stn, 6th, 7th and 8th generation, or from 3 previous studies with broilers from commercial strains (n=118). In each experiment, individual diet (wheat or maize) AMEn values or protein digestibilities (PD) were measured at 3 weeks. Weights of empty gizzards and small intestines relative to body weight (G and I, respectively) were also measured at various ages from 22d to 62d. Phenotypic correlations between recorded traits were performed on data corrected for diet and age effects. In birds from Digestion lines, AMEn values were positively correlated to G (r = 0.32; 0.24) and G/I (r= 0.57; 0.42) and negatively correlated to I (r = -0.79; -0.46), with wheat and maize diets, respectively. In contrast, no significant correlation was found between AMEn and G in commercial birds. However, in commercial birds fed wheat diets, AMEn was also negatively correlated to I (r = -0.41) and positively correlated to G/I (r =0.32). PD was positively correlated to G (r = 0.35; 0.28) and G/I (r = 0.47; 0.36), and negatively correlated to I (r = -0.36; -0.17) in birds from Digestion lines and commercial strains, respectively. Cereals (wheat versus maize) did not affect regressions between PD and anatomic data neither in Digestion lines nor in commercial strains. (Résumé d'auteur