Tenderness is the most important organoleptic characteristic of meat, and various methods have been developed to improve it. The purpose of this experiment was to evaluate the effect of different conditioning treatments of broiler carcasses on pH, cooking losses, shear values, R-values, and sensory tenderness of breast meat. All measurements were collected for breast muscle as follows: after 24 h of carcass aging (T1); after 24 h of carcass aging with muscle tensioning (T2); after 24 h of carcass aging with muscle tensioning, followed by muscle collection and marination in CaCl2 (T3); after hot-boning 15 min following slaughter (T4); after hot-boning 15 min following slaughter and marination in CaCl2 (T5). pH values in meat treated with CaCl2 were significantly lower than those in untreated meat from the aged carcass group (T3) or the hot-boning group (T5). Breasts from carcasses aged for 24 h (T1, T2, and T3) showed lower cooking loss than breasts harvested immediately after slaughter (T4 and T5). CaCl2 marination produced meats with cooking losses significantly higher than those observed for untreated meats. Regardless of muscle tensioning or marination treatments, aging of the carcass for 24 h (T1, T2, and T3) produced meats with lower shear values than those from hot-boned carcasses (T4 and T5). Hot-boned breasts treated with CaCl2 (T5) were judged less tender by panelists than breasts aged under muscle tensioning (T2 and T3).

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An experiment was designed to verify the effect of dietary NaHCO3 supplementation on performance of guinea fowl raised under high environmental temperatures (23.8 to 33.9 C) and average relative humidity of 78.7%. One hundred and forty guinea fowl in their final period of growth (56 to 84 d of age) were allotted to individual wire cages. Five isocaloric (3,000 kcal ME/kg) 16% CP diets based on corn and soybean meal and containing 0, 0.6, 1.2, 1.8, and 2.4% sodium bicarbonate were fed to the birds. The experiment followed a randomized block design with 28 birds per treatment (14 of each sex) with each bird being considered as one repetition. Results showed that weight gain, feed intake, feed conversion, mortality, blood pH, carcass yield, and carcass composition were not affected (P > 0.05) by dietary sodium bicarbonate supplementation. Weight gain, feed intake, feed conversion, carcass moisture, and fat content, however, were significantly (P < 0.05) affected by sex. Females showed 17.49% better weight gain, 7.16% greater feed intake, and 9.6% better feed conversion than males. These differences were exacerbated at supplementation levels of 1.2 and 1.8% sodium bicarbonate in the diet. Male birds showed carcass moisture values significantly (P < 0.05) greater than those of female birds; the opposite occurred with carcass fat levels. The use of sodium bicarbonate in levels up to 2.4% of the diet did not affect the performance of guinea fowl raised under the environmental conditions registered in this study.