Meat quality of heat stressed broilers: effects of thermal conditioning at pre- and -postnatal stages.
Makaleler > Tam Makale · 2005
Yazarlar: Zişan Servet YALÇIN, Alper Önenç, Sezen ÖZKAN, Hüseyin Cem GÜLER, P.B. Siegel
, Uluslararası, 2005, ss 145-150
Özet
Summary This study was conducted to investigate the effects of exposure of eggs to heat during incubation and heat conditioning chicks at 5 d on the meat quality of broilers reared under heat stress. The 1,000 eggs used in this experiment were obtained from younger (YBB, 28 wks) and older (OBB, 58 wks) broiler breeders from the same genetic stock. Eggs were randomly divided into two incubation temperature groups. 1). Standard (SInc) where eggs were incubated at 37.8oC from d 1 to 18 of incubation; 2). High (HInc) where eggs were heated at 39.6oC for 6 h daily from d 10 to 18 of incubation. At hatch, chicks were placed into 36 floor pens and chicks from 12 pens (3 pens/parent age/incubation temperature) were heat-conditioned (Cond) at 5 d of age for 24 h. At 21 d of age, 3 pens/parent age/incubation temperature were kept as controls (C), and the remaining broilers (including group Cond) were heat stressed (HS) daily from 21 to 49 d and then slaughtered. After postchilling, samples of pectoralis muscle were taken and pH, colour, thawing, and cooking loss and shear force were measured. Breeder age interacted with incubation and rearing temperatures and influenced meat quality. Age of breeder was significant for meat colour and pH, with meat from YBB broilers less light, redder, and less yellow with higher pH. HInc increased L* and b* values but decreased a* values in meats from OBB broilers. In the YBB group, pH was lower for HS broilers and the pH of meats of Cond and C broilers were similar. Although incubation temperature had no effect on cooking loss from YBB broilers, cooking loss from OBB broilers was decreased by HInc. Rearing temperature affected cooking loss with meat from YBB broilers being lower than that for broilers reared at HS.