Effect of Feed Restriction on Performance, Carcass Composition and Physicochemical Properties of the M. Pectoralis Superficialis of Broiler Chickens

The aim of this study was to evaluate the effect of feed restriction on carcass composition, breast meat quality and microstructure of the m. pectoralis superficialis of broiler chickens. A total of 315 day-old female broilers (Ross 308) were randomly assigned to 3 groups of 105 birds each in 3 pen replicates. They were fed ad libitum as the control (I), and restricted for 6 h/day (from 08:00 to 14:00 h) as group II (3 and 4 weeks of age) and group III from 4 to 5 weeks of age. On day 42 of growth, 6 broilers with average body weight were chosen from each group for slaughter to analyse dressing percentage, carcass quality, physicochemical properties of breast muscles, including pH, colour (CIE L*a*b*), expressible juice, drip loss, thawing loss, cooking loss, Warner-Bratzler shear force, texture (TPA) and chemical composition, as well as histochemical profile of the m. pectoralis superficialis. Temporary feed restriction did not significantly alter the final body weight, dressing percentage and the proportion of breast and leg muscles, but increased the proportion of abdominal fat. No differences were found in the microstructure of the m. pectoralis

superficialis of restricted and ad libitum fed chickens. Restricted feeding had an effect on water holding capacity and tenderness of breast muscles, and a non-significant effect on texture parameters and chemical composition. Restricted feeding of chickens changed their meat quality to a greater extent when applied from 3 to 4 weeks compared to analogous procedures introduced from 4 to 5 weeks of age.