The effects of the dark house system on growth,performance and meat quality of broiler chicken

Meat production with minimum animal suffering is a humanitarian concern. Thus, the objective of this work was to observe the performance of Cobb broiler chickens from 7 to 46 days of age when raised under different installations: dark house system (DHS), conventional yellow system (CYC) and conventional blue system (CBC). The feed conversion ratio for the birds raised on the DHS was 3.8% and 2.7% lower than those for the CYC and CBC systems, respectively. Compared with the CYC and CBC systems, average daily gain under the DHS was 11.4% and 9.3% higher, respectively, and body weight at 46 days was 11.4% and 9.3% higher, respectively (P ≤ 0.05). The birds' welfare was assessed based on their stress by determining the amount of pale, soft and exudative (PSE) meat in the breast fillets. The CYC and CBC birds had 24.3% and 25.3% PSE meat, respectively, whereas the DHS birds had 37.0%. We concluded that the DHS has a greater potential to produce broiler chickens, with superior performance to conventional systems, despite the higher stress faced by the birds during the maneuvers just before slaughter.     

Threonine incorporation in tissues of growing broiler chickens using L-[15N] threonine

Most amino acid requirement trials appear for whole-body responses, but there is little information concerning amino acid incorporation in individual tissues, which may vary according to the age. L-[¹⁵N] threonine was used to evaluate its incorporation rate and distribution among broiler tissues in different ages. Seventy-two male broiler chickens were distributed into three different phases: starter (4 to 9 days old), grower (18 to 23 days old) and finisher phase (32 to 37 days old). L-[¹⁵N] threonine was added on balanced diets, and birds were fed for five days in each phase. Enriched samples of breast muscle, feathers, liver, jejunum and plasma were collected at 0, 6, 12, 24, 48, 72, 96 and 120 hr after fed birds with the tracer in each phase. In the tissues were analysed dry matter, nitrogen and stable nitrogen. The ¹⁵N isotope abundance according to the time was fitted into exponential or linear equations using a same intercept. The ratio of the steepness or slope coefficients was determined to compare the L-[¹⁵N] threonine incorporation according to the age. In addition, L-[¹⁵N] threonine mass balances were performed to assess the L-[¹⁵N] threonine distribution among the evaluated tissues. Except for feathers, the L-[¹⁵N] threonine incorporation rate decreased with ageing. Taking into account the L-[¹⁵N] threonine distribution in the tissues, only in the jejunum was not observed an increase as the broiler grew. The L-[¹⁵N] incorporation varied in each tissue and according to the age of the broiler chickens. These outcomes could be useful to comprehend changes in amino acid requirements tissue-specific according to age.     

Improving transport container design to reduce broiler chicken PSE (pale,soft, exudative) meat in Brazil

Throughout the chicken production chain, transport from farm to the commercial abattoir is one of the most critical sources of stress, particularly heat stress. The aim of this work was to describe the performance of a new prototype truck container designed to improve the microenvironment and reduce the incidence of pale, soft and exudative (PSE) meat and dead on arrival (DOA) occurrences. Experiments were carried out for four different conditions: regular and prototype truck, both with and without wetting loaded cages at the farm (for bird thermal stress relief) just before transporting. While there was no difference in the DOA index (P ≥ 0.05), the prototype truck caused a reduction (P < 0.05) in the occurrence of PSE meat by 66.3% and 49.6% with and without wetting, respectively. The results of this experiment clearly revealed a low‐cost solution for transporting chickens that yields better animal welfare conditions and improves meat quality.