Effects of environmental factors on breast blister incidence, growth performance, and some biochemical indexes in broilers

Breast blisters (BB) are an important factor affecting the carcass grade of broilers. To investigate the effects of floor type, stocking density, and sex management on the incidence of BB, an orthogonal design with 3 factors and levels [L-9(3(4))] was used in this study. A total of 324 Arbor Acre broilers, 21 d of age, were randomly allocated into 9 groups with 2 replicates each, and were raised in cages with different floor types ( wire netting, plastic slats, and bamboo slats), at different densities (17, 14, and 11 broilers/m(2)), and with different sex management (males, females, and mixed sexes). Effects of these factors on the incidence of BB, growth performance, and some biochemical indexes were studied for birds from d 21 to 42. The results showed that floor type had the greatest effect on the incidence of BB compared with stocking density and sex management. The incidence of broiler BB was significantly higher in cages with wire netting than in those with plastic or bamboo slats (P < 0.05) and was significantly higher in cages with 17 broilers/m(2) than in those with 11 broilers/m(2) (P < 0.05); however, there were no obvious differences between sexes. Feed intake, BW gain (BWG), and FCR were not affected by floor type. The BWG of birds from d 21 to 42 was higher in broilers housed at densities of 14 and 11 broilers/m(2) than in those housed at 17 broilers/m(2) P < 0.05). The BWG of male birds was higher than those of female birds and birds in the mixed-sex group (P < 0.05). Serum lactic acid content was higher in birds reared on wire netting than in those reared on bamboo slats (P > 0.05). Birds on plastic slats had higher total antioxidant capability values than those on wire netting or bamboo slats (P < 0.05). Malondialdehyde content of birds in the wire netting group was higher than those of birds on plastic and bamboo slats (P < 0.05). In this study, floor type was the main environmental factor affecting the incidence of BB in broilers, compared with density and sex management. Results suggest that the increased serum levels of lactic acid and malondialdehyde are involved in the development of BB.