Abstract
Two experiments will be performed in order to evaluate the influence of organic minerals (selenium and zinc) on the incidence of foot dermatitis contact, incidence of injuries and skin resistance, and also evaluate the influence of these minerals combined with vitamin E on the characterization histopathology of foot dermatitis, meat quality, performance and carcass quality and immune system in broilers. The experiments it will conduct in the experimental shed FMVZ-UNESP/Botucatu in each experiment will be used 1080 one day-old chicks of the Cobb® males housed with a density of 12 birds/m², for 42 days. Feeding will be divided into four phases: pre-starter (1-10 days), early (11-21 days), growth (22-35 days) and late (36-42 days). In experiment 1, the experimental design is completely randomized in factorial 3x2, with three levels of organic zinc (0, 45 e 90 mg/kg of feed) and two levels of organic selenium (0 e 0.3 mg/kg of feed) with 6 replicates of 30 birds each. At 42 days into the aviary will be accomplished the macroscopic evaluation of the legs of all birds for the classification of the injuries scores. Also at 42 days, 48 birds per treatment will be slaughtered to evaluate the incidence of skin lesions and endurance, and histological collection of skin and foot dermatitis. In experiment 2, the experimental design is completely randomized in factorial 3x2, with three levels of vitamin E (0, 50 and 100UI/kg diet) and two levels of organic selenium and zinc (control and the best dosage obtained in experiment 1) with 6 replicates of 30 birds each. Will be carried out analysis of immunological parameters, using blood samples at 10, 21 and 42 days. At 42 days of age all birds will be evaluated in the aviary for macroscopic score foot callus. Also at 42 days of age, 40 birds per treatment will be slaughtered at the abattoir experimental FMVZ/UNESP following steps stunning, bleeding, scalding, evisceration and cooling of the carcasses. Will be collected all the legs of birds slaughtered, for the implementation of microbiological tests to assess the presence of E. coli, Clostridium and Staphylococcus sp perfingiens. Later will be the weighing of carcasses and parts with and without bone. Boneless breasts will be collected, identified for the analysis of meat quality. At 24 hours post-mortem will be evaluated pH, objective color and drip loss. For analysis of cooking loss, shear force, the samples will be frozen at -20°C until the time of analysis. For the analysis of TBARS (thiobarbituric acid reactive substances) and MFI (myofibrillar fragmentation index) after the breasts are boned, packaged in plastic containers appropriate, and sealed under vacuum, will be frozen (-18°C) through three storage periods 0, 45 and 90 days. (AU)