Fernanda G. Paião

Molecular cloning of αRYR hotspot region 1 from broiler chicken

Samples of Pectoralis major m. were collected, and an RT-PCR analysis of the α- Ryanodine receptor ( α RYR) from chicken mRNA hotspot region spanning aminoacid resi dues 386 to 540, numbered according to the turkey s equence, revealed two classes of transcripts. The sequences of the first class were similar to turkey and human with 97% and 74% of identity, respectively, and included all tra nscripts with substitutions in the nucleotide seque nce. The second class was characterized by the deletion of nucleoti des, leading to a premature stop codon and coding f or a truncated and nonfunctional protein. These results are to date the first report related to the sequenc ing of the chicken αRYR hotspot region 1, which will possibility serve as a guide for further studies regarding a solution in the poultry production chain related to the problem of pale, soft and exudative (PSE) meat.

Influence of Cooling on the Glycolysis Rate and Development of PSE (Pale, Soft, Exudative) Meat

The aim of this work was to evaluate pH values fall rate in chicken breast meat under commercial refrigeration processing conditions and the development of PSE (pale, soft, exudative) meat. Broiler breast samples from the Cobb breed, both genders, at 47 days of age (n = 100) were taken from refrigerated carcasses (RS) immersed in water and ice in a tank chilled at 0°C (±2). pH and temperature (T) values were recorded at several periods throughout refrigeration in comparison to samples left at room T as control (CS). The ultimate pH (pHu) value of 5.86 for RS carcasses were only reached at 11°C after 8.35 h post mortem (PM) while, for CS samples, pHu value was 5.94 at 22°C after 4.08 h PM. Thus, under commercial refrigeration conditions, the glycolysis rate was retarded by over 4.0 h PM and the breast meat color was affected. At 24.02 h PM, PSE meat incidence was 30% while for CS, meat remained dark and PSE meat was not detected. Results show retardation in the glycolysis rate and PSE meat development was promoted by the refrigeration treatment when compared with samples stored at processing room temperature.