A mating scheme based on molecular parentage improves growth performance in slow- growing chickens over three generations

The objective of this study was to assess the effect on growth traits of a mating scheme aimed to minimize progeny inbreeding using genomic information. 150 birds (75 males and 75 females) of Bianca di Saluzzo, a slow growing breed autochthonous of Piedmont region, were genotyped by a set of 14 microsatellite markers. For each subject the genetic distances were calculated. Six family lines were identified and 10 hens for each line were grouped in a single box. For each line the cock with the highest genetic variability was identified and coupled with the most distant female genetic line. 440 individuals of three generations (G0, G1 and G2) were weighted every 15 days from hatch to 180 days of age; Gompertz linear model was used to describe the growth index over the three generations. Daily growth rate significantly increased (P < 0.001) over successive generations in males (G0 = 16 g/d; G1 = 20 g/d; G2 = 25 g/d) and in females (G0 = 12 g/d; G1 = 14 g/d; G2 = 28 g/d). The age Inflection point significantly decreased (P<0.05) in males (G0 = 101 d; G1 = 93 d; G2 = 68 d) and in females (G0 = 90 d; G1 = 87 d; G2 = 62 d). The live weight corresponding to the inflection point decreased (P=0.06) over the generations in males (G0 = 1230 g; G1 = 1156 d; G2 = 1148 g) and in females (G0 = 881 g; G1 = 835 d; G2 = 794 g). The estimated weight at 180 days of age increased over the generations: +28% in cocks (G0 = 2288 g; G1 = 2470 d; G2 = 2853 g) and +13% in hens (G0 = 1758 g; G1 = 1810 g; G2 = 1988 g). In conclusion, the results showed an improvement of growth performance as the offspring heterozygosity increased and inbreeding decreased. The use of molecular parentage in mating schemes could be a reliable tool for the management of small size chicken populations and the improvement of their production.