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The objective of this experiment was to test the effects of the addition of chlorine to broiler drinking water during a 12-h preslaughter feed withdrawal period on reduction of the quantities of microorganisms, such as Escherichia coli and enterococci, in broiler crops and ceca. Reduction of these microorganisms would likely also reduce contamination of broiler meat by pathogenic bacteria during processing. It was also investigated if the chlorine caused some intestinal damage that could disseminate the microorganisms to the carcass. A total of 40 Cobb male broilers were used. Samples of crop and cecal content were collected for microbiological analysis, and duodenum and jejunum were used for morphological analysis from 10 birds in each treatment. The most probable number (MPN) of E. coli and enterococci in the collected samples of crop and ceca and the measure of the free residual chlorine in water were determined. The scanning electron microscopy from duodenum and jejunum was used to illustrate the mucosa integrity. The chlorine added to water was efficient in reducing the quantities of microorganisms in broiler crops and improved the integrity of the mucosa. Therefore, preslaughter feed withdrawal should be coupled with crop disinfection, because preslaughter feed withdrawal increases the MPN of enterococci and E. coli in broiler crops. So, it presents a higher risk for carcass contamination during slaughterhouse processing and, consequently, a higher risk for public health.

The objective of this experiment was to determine the normal values of bone radiographic density (BRD) by using the optical densitometry in radiographic images and the biochemical values represented by serum calcium, ash percentage, and minerals (calcium, phosphorus, and magnesium) from tibia ash of Cobb broilers at 8, 22, and 43 d of age. A total of 14 broilers were used for densitometric analysis, and 15 were used for biochemical dosages. The BRD values increased (P < 0.05) with age and in all tibia regions (proximal epiphysis, diaphysis, and distal epiphysis), concluding that growth was a determinative factor for bone performance, demanding a higher BRD during broiler development. Tibia proximal epiphysis presented higher BRD values in relation to the other bone regions (P < 0.05), as a result of a possible biomechanical adaptation to ligaments and tension of the muscle tendons at this region, allowing the support of the muscle mass increase. The serum calcium values were kept constant, as a result of the appropriate nutritional levels of the diet that supported the animal homeostasis. The bone ash and mineral percentage increased (P < 0.05) at 22 d of age, due to the higher mineral requirement in this age. The correlation between bone densitometry and the invasive techniques showed that the bone densitometry can substitute the determination of mineral percentage in the ash. This experiment presented normal values of the noninvasive and invasive methods more used in aviculture, allowing us to compare, subsequently, pathological and physiological values or results of broilers fed with different diets.