EFFECTS OF CRATING AND TRANSPORT ON STRESS AND MEAT QUALITY CHARACTERISTICS IN BROILERS

Experiments were conducted to determine 1) whether different crating d urations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticos terone (CORT) levels and meat quality. In a preliminary experiment, ma le broilers (n = 50) were held in crates (10 birds per crate) for eith er 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not af fect plasma CORT level, cooking loss, shear value of breast or thigh m uscles, or carcass skin discolorations. Crating duration also did not affect the color (L, a*, b*, chroma, and hue angle) of breast meat, b ut did change the color of thigh meat, with samples from the 3 h crati ng group having the highest hue values (P < 0.01). Corticosterone conc entrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not infl uence plasma CORT, epinephrine, or norepinephrine concentrations, init ial pH, color, or texture of breast and thigh meat samples. in Experim ent 2, broilers were crated (nine birds per crate) early in the mornin g and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Cor ticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affec ted by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a signific ant correlation (P < 0.01, r = 0.302) between CORT levels and hue valu es of thigh meat. These results suggest that higher preslaughter stres s levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this st udy.