Abstract:
Spent chicken layers are available for meat after completion of their egg production year(s) but there is a dearth of information on the quality of such meat. Thus, this study investigated the effect of three different breeds of spent laying chickens (Barred Plymouth Rock, Bovan Brown and Harco Black) at different ages (12, 18 and 24 months in lay) on the serum cholesterol, carcass characteristics and meat quality. A completely randomized experimental design in a 3 x 3 factorial arrangement was adopted in which 54 spent layers were used. There were 18 chickens per breed with 6 chickens per age group. The birds were fed with commercial layers mash (16% CP) for 3 weeks before assessment. Carcass and organ characteristics were measured. Serum cholesterol content, proximate composition, cooking loss, tenderness, juiciness and oxidative stability of meat were determined. The study revealed that Harco Black had the highest live weight (P<0.05), followed by Bovan Brown and the lowest was Barred Plymouth Rock. Live weight and chicken parts generally increased with increasing age of the spent layers (P<0.01). The giblet weights were significantly (P<0.05) higher for 18 and 24-month old layers than those of 12 months. Harco Black had the highest (P<0.01) muscle fat content and cooking loss while the lowest was recorded for Barred Plymouth Rock. Fat contents of the meat increased with increasing age of the spent layers. Protein content of meat from Barred Plymouth Rock was higher than that of Bovan Brown and Harco Black. The chicken thigh had the highest fat content and cooking loss when compared with drumstick and breast. Oxidative stability of the spent layer was not significantly (P>0.05) influenced by breed and age, but by muscle type (higher in breast than drumstick and lowest for thigh). The tenderness and juiciness of meat from the chickens were not affected (P>0.05) by breed and age of the spent laying chickens. Harco Black had numerically highest serum cholesterol content and the serum cholesterol increased with increasing age of the spent layers (P>0.05). It was concluded that spent layer of Barred Plymouth Rock breed is preferred, followed by Bovan Brown and least for Harco Black in terms of meat quality. The 12 months old spent layers had the best meat quality.
