Desempenho e qualidade de carcaÃa e carne de frangos criados em sistema alternativo / Performance and quality of carcass and meat of chickens raised in an alternative system

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

This work was intended to evaluate the characteristics of performance, carcass and cut yield, centesimal, physicochemical composition and morphometric characteristics of the muscle fiber and conjunctive tissue of the strains ParaÃso PedrÃs (fast-growing) and PescoÃo Pelado (slow-growing) of both sexes (males and females), reared in an alternative system and slaughtered at four slaughter ages (65, 75, 85 and 95 days). The experiment was conducted in CRD (completely randomized design) in the factorial scheme 2 x 2 x 4 (two strains, two sexes and four slaughter ages) and 3 replicates, each replication being made up of four chickens. The experiment was undertaken in the Federal Center of Technological Education of CuiabÃ. The analyses of centesimal and physicochemical composition were carried out in the Food Science Department of the Federal University of Lavras, Lavras-MG. The analyses of morphometry of muscle fiber and conjunctive tissue were performed in the Institute of Tropical Pathology and Public Health of the Fderal Univesity of GoiÃs, GoiÃnia-GO. A study of performance of the birds at start (1 to 28 days) and finish phase (29 to 95 days), with the determinations of Live Weight (PV), Feed Consumption (CR), Daily Average Weight Gain (GMPD) and Feed Conversion (CA) was accomplished. The performance results revealed that during start phase the strains presented similar behavior, with increased destaque for live weight and weight gain for ParaÃso PedrÃs at finish phase. As far as the carcass is concerned, the live weight of slaughter (Pva), carcass weight (Pc), carcass yield (Rc), cut yield (breast, thigh, drumstick, dorsum, neck and wings), abdominal fat yield (Ga) and eatable vÃsceras yield (Rvc) (moela, heart and liver) was determined. The results for both Pva and Pc showed higher values in the strain ParaÃso PedrÃs strain, with higher means for males. The breast yield was higher in the ParaÃso PedrÃs strain and in female. The thigh and drumstick yields were higher in PescoÃo Pelado animals and in males. The dorso results were similar at 85 and 95 days. Wing yield reduced as slaughter age increased. The Ga values showed higher means in ParaÃso PedrÃs and in females. The Rvc was influenced by both sex and slaughter age. In the evaluation of the centesimal composition, it was found that the content of moisture and protein for the breast reduced as related to the age and there were no differences between the strains, while for thigh, moisture showed differences between the strains at 85 days with greater means for PescoÃo Pelado and the protein values were lower at 75 days. Lipid content in both the cuts was greater for ParaÃso PedrÃs, it increased as related to age and was higher in females. As regards ash content, for breast, higher values were found at 95 days and fro thigh, there was no difference from 85 days, with increased mean for females in both cuts. Also, the following physicochemical analyses were performed: Color (CIELAB system), final pH, shearing force (FC) and Weight Loss by Cooking (PPC) fro breast and thigh. The luminosidade values (L*) reduced for breast and thigh as related to age; the values of red index (a*) were higher in the breast for males and in the thigh for females; and in the breast, higher values of yellow index (b*) were found for PescoÃo Pelado, while in the thigh, greater means were verified in ParaÃso PedrÃs. The pH values of the breast were lower for ParaÃso PedrÃs and females, whereas for thigh, those values were lower for PescoÃo Pelado. The FC increased as age for both the cuts increased and showed no difference of strain and sex for breast, whilst for thigh, higher values were reported for PescoÃo Pelado. The values of PPC in the breast were greater for males, for thigh they were higher for females and PescoÃo Pelado chickens. In the morphometric study of the of the muscle fiber diameter and conjunctive tissue of the breast and thigh, the influence of slaughter age for these parameters was verified, showing similar behavior in relation to the variation of sex and strain.

ASSUNTO(S)

ciencia de alimentos muscle fibers meat quality broiler qualidade de carne frango alternative system sistema alternativo fibra muscular carne meat

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