The impact of eggshell colour and spot area in Japanese quails: II. Slaughter and carcass characteristic

ABSTRACT This study was carried out to investigate the effects of eggshell colour and spot properties (colour and size of the spot area) on growth performance and carcass traits of Japanese quail (Coturnix coturnix japonica) eggs. Study material were allocated to five groups according to their eggshell and spot colours: black spots on greyish white coloured eggshell (I), blue spots on greyish white coloured eggshell (II), diffuse brown spots on greyish brown coloured eggshell (III), brown spots on light green colored eggshell (IV), and small brown spots on greyish brown coloured eggshell (V). The size of the spotted area was determined in each egg group using digital image analysis. The groups did not differ for body weight and length of the shank at the end of the growth period. However, the groups differed significantly for carcass yield after slaughter (not eviscerated) and carcass yield. These parameters were highest in Group I (82.08 and 76.09%) and lowest in Group III (80.20 and 73.86%). Digital image analysis demonstrated that heart length, cardiac fat area, gizzard width, and intestine length varied between the groups. Cardiac fat area was largest in Group III (0.86 cm2) and smallest in Group V (0.65 cm2). Gizzard width was greatest in Group I (2.63 cm) and smallest in Group V (2.47 cm). Intestine length was greatest in Group V (78.45 cm) and smallest in Group IV (72.39 cm). Body weight, shank length, and slaughter and carcass weight do not vary in relation to eggshell colour or the size of the spotted area. The lengths of intestine and heart, gizzard width, and cardiac fat area do vary in relation to eggshell colour or the size of the spotted area.