ABSTRACT This study investigated the effect of calcium (Ca) and phytase interaction on growth performance and bone quality in 1-42-day-old broiler chickens. A total of 624 female one-day-old Ross 308 broilers were allotted to 13 treatments with four replicates and 12 birds per replicate. A 2 × 6 factorial experiment was designed to test the combinations of 0.50% and 1.00% Ca with 0, 500, 1,000, 2,500, 5,000, and 10,000 FTU/kg phytase in the basal diet (0.25% non-phytate phosphorus, NPP). The control diet contained adequate Ca and phosphorus (P). Dietary Ca, phytase, and their interaction affected growth performance and bone mineralization of broilers at 1-42 days of age (p<0.05). The broilers fed with 1.00% Ca had lower body weight gain (BWG) and feed intake (FI) compared with the birds fed with 0.50% Ca (p<0.05). The BWG, FI, leg bone weight, and ash weight of the broilers fed with 0.25% NPP were lower than those of birds fed with the control diet (p<0.05). The addition of 500-10,000 FTU/kg phytase improved growth rate and leg bone quality, especially at 1.00% Ca (p<0.05). No differences were observed in growth performance and bone quality of 42-day-old broilers fed with 1.00% Ca + 2,500-10,000 FTU/kg phytase and the control diet (p>0.05). These data indicated that high doses of phytase (2,500-10,000 FTU/kg) alleviate the negative effects of Ca and P imbalance (Ca-to-NPP ratio = 4.0) on growth performance and bone mineralization of broiler chickens.

ABSTRACT This study aims to investigate whether resveratrol (RES) could inhibit NF-κB activity and protect in vitro cultured chicken lymphocytes from apoptosis induced by continuous LPS stimulation. Blood lymphocytes of chickens were collected and cultured. LPS was added to the samples of treatment group, while the same volume of normal saline (NS) was supplemented to those of the control group. In the treatment groups, four different concentrations of RES (0, 20, 40, and 80 µg/ml) were admixed. Then, the following indicators were tested: lymphocyte apoptotic rate, lymphocyte viability, NF-κB activity, TNF-a level, reactive oxygen species (ROS), and expression of apoptosis-related proteins (Fas/FasL and Caspase-8). The results indicated that the application of different concentrations of RES could significantly increase the viability of lymphocytes and decrease the apoptotic rate (p<0.05) after continuous stimulations by LPS. The activity of NF-κB levels of TNF-a and ROS in the RES treatment subgroups was significantly decreased in comparison with that in the RES-blank subgroup (p<0.05). The cells in the treatment group that had been treated with 20, 40 and 80 μl/ml of RES exhibited a significantly lower Fas and Caspase-8 expression level than that in the RES-blank subgroup (p<0.05). These findings revealed that RES could substantially diminish the concentrations of ROS and TNF-a, down-regulate NF-κB activity, decrease the expression of Fas and Caspase-8, stimulate the activity of peripheral lymphocytes, and lower the rate of their apoptosis, induced by continuous LPS stimulation in chicken lymphocyte cultures.