ABSTRACT This study was conducted to evaluate the impact of litter type and litter treatment with enzymatic-bacterial production incidence and severity of footpad dermatitis and consequently on behavior of broiler chickens. A total of 1,200 one day-old Ross 308 broilers were randomly allocated to 4 treatments with 4 replicates in 2 x 2 factorial design. The first factor was the physical form of the straw (chopped on approximately 2 cm or un-chopped) and the second factor was addition of enzymatic-bacterial product applied directly on the straw. Each replicate consisted of 75 as-hatched birds per pen. Occurrence and severity of the footpad dermatitis and histological evaluation of the scores was done at the end of the trial (42 days of age). During the trial, at 3 and 6 weeks of age, broiler behavior was observed by Scan Sampling Method. The results showed that chopped straw significantly lowered the incidence of footpad dermatitis. Chopped straw in combination with enzymatic-bacterial product showed the lowest footpad dermatitis score in broilers. Histological procedures confirmed the macroscopic evaluation of the footpad dermatitis severity. The chopped straw had a significant effect on some behavioral patterns of broiler chickens. Differences were observed for dust bathing and scratching. Correlation between footpad dermatitis and birds locomotor activity was not confirmed.

This study was performed to determine the effects of a natural yeast-based feed ingredient (natural carbohydrate fraction (NCF) isolated from a specific strain of yeast) on broiler chickens, and to examine its mode of action. The trial was set up as a complete randomized design with three treatments and eight replicates (38 Ross 308 chickens per pen). Two levels of NCF, 0.2 g/kg and 0.4 g/kg, were compared to a negative control. The NCF addition increased body weight during the initial period, but this benefit was lost towards the end of the trial. Feed conversion ratio was improved significantly with 0.4 g NCF/kg (1.79 compared with 1.83 in control group). Mortality was numerically lower in the groups receiving NCF. Significant effects on caecal bacterial population were not found. Intestine length and weight were not affected by treatments, while some changes in intestine histology were found. The area described as the 'cup' of mucus-producing cells, representing the quantity of stored mucins, was significantly larger in chickens receiving NCF. Relative weights of the spleen and bursa of Fabricius did not change significantly compared with the control. The NCF can improve performance and affects mucus-producing cells. Full elucidation of the mechanisms of action requires further research.