Effects of reducing dietary amino acid density and stocking density on growth performance, carcass characteristics, meat quality, and occurrence of white striping in broiler chickens


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Pekel A. Y. , Cengiz Ö., Tatli O., Sevim Ö., Kuter E., Köksal B. H. , ...Daha Fazla

2020 International Poultry Scientific Forum, Georgia, Amerika Birleşik Devletleri, 27 - 28 Ocak 2020, ss.8

  • Basıldığı Şehir: Georgia
  • Basıldığı Ülke: Amerika Birleşik Devletleri
  • Sayfa Sayıları: ss.8

Özet

A 49-d trial was conducted to determine the impact of dietary amino acid (AA) density and stocking density (SD) on growth performance, carcass traits, meat quality, and white striping (WS) occurrence in broiler chickens. A total of two hundred eighty eight Ross 308 male broilers consisting of 6 replicate cages with 8 broilers per replicate were used. Treatments were arranged in a 3 × 2 factorial and consisted of 3 AA densities [normal (Norm), 10% lower than Norm (10%low), or 20% lower than Norm (20%low)] and 2 different SD (High; 35 kg/m2 or Low; 26 kg/m2 ). Data were analyzed as a completely randomized design using the GLM procedure of SAS. Decreasing AA density decreased overall growth performance, carcass and breast yields and breast fillet dimensions linearly, whereas leg and rib cage yields increased linearly (P < 0.01). High SD decreased hot carcass, breast, wings, and rib cage weights in birds fed on Norm AA diets (P < 0.05). High SD increased the length of breast fillet (P < 0.05). Cooking loss, breast lightness (L*) and redness (a*) at 48 h postmortem increased linearly with decreasing AA density (P < 0.01), whereas breast ultimate pH (pHu ) decreased linearly (P < 0.001). Low SD caused a decrease in breast yellowness (b*) at 24 post mortem in birds fed on norm AA diet (P < 0.05). Nitrogen content of breast fillets decreased linearly with decreasing dietary AA density (P < 0.05). Breast muscles having severe WS contained higher fat when compared with breast muscles with moderate or no WS (P < 0.05). As the dietary AA density decreased, occurrence of no WS breast fillets increased, whereas occurrence of moderate WS fillets decreased (P < 0.005). However, dietary AA density did not affect the occurrence of severe WS fillets. Stocking density did not affect the occurrence of WS. Breast fillets having severe WS had higher pHu and less b* than normal breast fillets (P < 0.05). There were no differences for water holding capacity and cooking loss between different degrees of WS. Taken together, growth depression created by lowering dietary AA density regardless of SD resulted in a decrease in mean WS score. Severe WS fillets were heavier and had higher pHu , fat, and lower b* but no difference in water holding capacity compared to no WS fillets.