1. The objective of the study was to investigate the effect of transport distance on blood metabolites and breast meat quality of broilers slaughtered at different weights. 2. The study was conducted on Ross 308 broilers from 27 different flocks reared under similar conditions. Slaughter weight was classified as <2·0 kg, 2·0-2·4 kg, and >2·4 kg. Transport distance was categorised as short (65 km), medium (115 km) and long (165 km) distance representing 90, 155 and 220 minutes at an average 45 km/h speed, for each slaughter weight. 3. Higher heterophils and heterophil:lymphocyte (H/L) ratios were obtained for broilers transported over a long distance. Long distance transport increased blood albumin, glucose, and triglycerides levels for <2·0 kg broilers, which did not differ from broilers slaughtered at >2·4 kg after long-distance transport. 4. Broilers slaughtered at >2·4 kg after long-distance transport had lower pH(u), and paler and tougher breast meat, than those broilers slaughtered at <2·0 kg after long-distance transport. 5. A negative correlation was obtained between pH(u) and L*, thawing loss and texture. The L* value was negatively correlated with a*; and positively correlated with b*, thawing and cooking losses. 6. It was concluded that the effect of transport distance could not be evaluated independently of slaughter weight. The interaction between transport distance and slaughter weight contributes to preslaughter stress and meat quality.

In the past 20 years, broiler production has increased in hot climate countries, due to a greater potential for further growth. Thus, there is a necessity to improve thermotolerance of broilers produced in hot climates. Incubation period will become increasingly important in enhancing thermotolerance, because higher temperatures during incubation may lead to an elevation of the thermoregulatory set-point after hatch. Two recent experiments, conducted to determine the effect of high incubation temperature (INC HIGH ) from d 10 to 18 on hatching performance and carcass characteristics of broilers, have been compared with broilers from incubated at control temperatures (INC CONT ). INC HIGH resulted in a delay in external pipping and hatching times compared with INC CONT . There was no incubation temperature effect on the weights of bursa of fabricius, spleen and lungs, and moisture content of chicks but lowered heart and liver weights. When broilers exposed to daily cyclic high temperature from 21 to 42 d, slaughter weight of broilers from INC CONT reduced while heavier body weight and breast yield were obtained in broilers from INC HIGH . It was concluded that higher incubation temperature from d 10 to 18 for 6 h/d had no effect on chick weights and minimized the negative effect of heat stress on slaughter weight and breast meat yield.

Hypoxia strongly affects embryonic development during the pre-hatch period. This study was conducted to investigate the effects of oxygen supplementation (O) and a 38.5°C high temperature (HT) at high altitude (HA, 1720 m) on morphological traits during a pre-hatch period and on relative fluctuating asymmetry (relative FA) and allometric growth during an early post-hatch period in broilers. A total of 720 eggs were obtained from a 45-week-old Ross 308 broiler breeder flock raised at sea level (2 m). The eggs were divided into six incubation condition (IC) groups and were incubated at HA. O groups were exposed to 23.5% O2 for 1 h daily from either days 0 to 11 (O0-11), days 12 to 21 (O12-21) or days 18 to 21 (O18-21) of incubation. HT groups were exposed to 38.5°C daily from either days 12 to 21 (HT12-21) or days 18 to 21 (HT18-21) of incubation. A control was maintained at 37.8°C and 21% O2. The hatched chicks were raised for 6 days at HA. Embryo/chick and beak lengths and head diameter were measured during pre- and post-hatch periods. The face, middle toe and shank lengths were measured for each chick. The relative asymmetry (RA), mean RA (MRA) and allometric growth of the lengths were computed and the existence of FA was demonstrated. The IC significantly affected the embryo length, with embryos of the O0-11 group shorter than embryos of the other O groups. Chicks were longer in the O and HT groups than those in the control, except for the O0-11. We found significant interactions between the IC and each development period for beak length. During the post-hatch period, the head diameter of the O0-11 was significantly smaller than that of the other groups, but not in O12-21. The interactions among IC, age and sex were significant for the RA of the face and middle toe lengths and for MRA. All the examined bilateral traits were evaluated as allometric growth. The FA for bilateral traits was determined in both sexes. The right (R) - left (L) and IR-Ll were the lowest in females for face length and in males for shank length from the O18-21 and in males for middle toe length from the O0-11 and HT18-21 groups. Therefore, the effects of factors such as HT and O2 could mitigate the adverse effects of HA-induced hypoxia on optimal developmental stability of bilateral traits of broiler.

No abstract

Bu çalışmada, kesim öncesi maruz kalınan akut stres (14 saat süreyle aç bırakılma) etmenine karşı, doğal bir yem katkı maddesi olan, farklı oranlarda humik asit (HA) ilavesinin, Japon bıldırcınlarında karkas parça randımanı, et kalite özellikleri ve bazı kan parametreleri üzerine etkilerinin incelenmesi amaçlanmıştır. Materyal ve Metot: Bu amaçla, toplam 184 adet karışık eşeye sahip Japon bıldırcını, dört gruba ayrılmış, gruplardan biri kontrol (HK, HA=0) olarak muhafaza edilmiş ve çalışmanın sonuna kadar ticari karma yem (KY) (%24 protein ve 2900 kcal/kg ME; NRC, 1994) ile beslenmiştir. Diğer 3 gruba, fizyolojik stresin etkilerini önleme amacıyla farklı dozlarda HA ilavesi yapılmıştır (H1=KY+%0.10 HA, H1.5=KY+%0.15 HA; H2= KY+%0.20 HA). Kesimden 1 gün önce tüm yem grupları 2 alt gruba ayrılmış (23 bıldırcın/grup) ve hayvanların yarısı 14 saat (açlık stresi, AS) diğer grup 3 saat süreyle aç bırakılmıştır (Kont.). Bulgular: Açlık stresi ve HA ilavesi karkas ağırlığını etkilememiştir. Tüm et kalite özellikleri AS uygulamasından etkilenmiş, HA uygulaması ise yalnızca pH24 üzerinde etkili olmuştur. Serum toplam protein seviyesi AS grubunda azalırken, LDH artmıştır. HA uygulaması, kontrol grubuna kıyasla H1.5 grubunda en yüksek LDH seviyesini göstermiştir. Sonuç: Kesim öncesi açlık stresinin bıldırcın göğüs eti kalitesini etkilediği, ancak yeme ilave edilen HA'in önemli bir etkisinin olmadığı görülmektedir.