The effect of genotype of broiler chickens on carcass quality in extensive rearing system

Abstract

Research was carried out on chickens of four genotypes: two slow-growing genotypes, Master Gris (MG) and Farm Q (FQ), one fastgrowing, Hubbard Classic (HC) and one medium-growing Red Bro (RB). To the age of 3 weeks, chickens were reared according to all technological norms for intensive production. After that period, chickens were moved and fattening in extensive conditions resumed, using unlimited free range. The significance of genotype on body mass was established. The greatest final body mass was established in chickens of the Master Gris genotype (1983 g) and the lowest in Farm Q (1371 g). Fast-growing chickens of genotype Hubbard Classic at the age of 84 days had body mass at the level of medium-growing Red Bro genotype at the age of 91 days (1730 g, and 1759 g, respectively). In accordance to the established body mass, slaughter yields of Farm Q broilers were significantly the lowest. Also, chickens of this genotype also had significantly (p (lt) 0.05) lower share of abdominal fat compared to other genotypes. Chickens of Master Gris and Red Bro genotypes had significantly greater shank length (22.57 and 21.01 g/mm, respectively), whereas in fast-growing genotype Hubbard Classic a significantly greater breast angle (90.15 degrees) was determined. Accordingly, share of breast (15.90 %), as well as share of breast meat (10.11 %) was significantly greater in carcasses of Hubbard Classic chickens.

Ovo ispitivanje je obavljeno na pilićima četiri genotipa: dva sporog porasta, Master Gris (MG) i Farm Q (FQ), jednog brzog porasta, Hubbard Classic (HC) i jednog 'medium-growing' Red Bro (RB). Pilići su do uzrasta 3 nedelje gajeni po svim tehnološkim normativima intenzivne proizvodnje. Nakon tog perioda, izvršeno je preseljenje pilića i nastavljen je tov u ekstenzivnim uslovima, sa korišćenjem neograničenog ispusta. Utvrđen je signifikantan uticaj genotipa na telesnu masu. Najveću završnu telesnu masu su postigli pilići genotipa Master Gris (1983 g) a najmanju Farm Q (1371 g). Brzo-rastući brojleri genotipa Hubbard Classic su u uzrastu od 84 dana imali telesnu masu u nivou 'medium-growing' genotipa Red Bro u uzrastu od 91 dana (1730 g, odnosno 1759 g). U skladu sa utvrđenom telesnom masom, i klanični randmani pilića Farm Q su bili signifikantno najmanji. Takođe, pilići ovog genotipa su imali i značajno (p (lt) 0,05) manji udeo abdominalne masti u odnosu na ostale genotipove. Pilići genotipa Master Gris i Red Bro su imali značajno veću dužinu piska (22,57 i 21,01 g/mm), dok je kod brzorastućeg genotipa Hubbard Classic utvrđen signifikantno veći grudni ugao (90,15 stepeni). Saglasno tome i udeo grudi (15,90 %), kao i udeo mesa grudi (10,11 %) je bio signifikantno veći u trupu pilića Hubbard Classic.