Morphological and genetic characterization of 13 Italian local chicken breeds

Abstract

According to census accomplished in 2001, only 9% of Italian poultry breeds are still widespread. This project aims to describe morphological variability and genetic background among 13 Italian autochthonous chicken breeds, 10 from Northern Italy and 3 from Central Italy. An updated biometrical measurement protocol was established starting from phenotypic characterization guidelines released by FAO. Six traits were registered on each animal: live body weight (LBW), body length (BL), shank length (SL), shank width (SW), breast width (BW), and wingspan (WS). Moreover, all breeds were genotyped using the Affymetrix 600 K Chicken SNP Array, in order to evaluate genetic variability and population structure. Means of BL and BW showed low variability among breeds, with the lowest value in Pepoi (BL = 32.29 ± 1.57 cm and BW = 28.92 ± 1.93 cm), and maximum in Robusta Lionata for BL (46.79 ± 1.66 cm) and in Robusta Maculata for BW (42.33 ± 3.60 cm). On the contrary, average LBW varied notably among breeds, with the highest value for Robusta Maculata (♂ 4,221.7 ± 450.6 g; ♀ 2,831.7 ± 253.2 g) and the lowest values for Modenese males (1,695.0 ± 128.1 g) and Pepoi females (1,293.3 ± 219.2 g). The lowest observed heterozygosity (Ho) and expected heterozygosity (He) were obtained for Padovana Argentata (Ho: 0.151 ± 0.198; He: 0.146 ± 0.185) and the highest for Millefiori di Lonigo (Ho: 0.293 ± 0.199; He: 0.291 ± 0.178). Furthermore, multidimensional scaling plot showed clear genetic identity for each breed, with clusters formed according to geographical and historical origin of the breeds, which were confirmed in neighbor networks. In conclusion, local breeds have conserved authentic genetic patterns and these results can help improve conservation strategies.