SUMMARY
In order to evaluate in vitro enzyme activity and in vivo efficacies of three new phytase products the diets of CON, Phy-500, Phy-1000 and Phy-5000 which were formulated to contain 0.0, 500, 1000 and 5000 FTU phytases per kg diet, respectively were analysed for their phytase activity by a universal method and fed to the 14 day-old quail chicks for 3 weeks. The results indicated that the universal method was successfully transferred at our laboratory (the precision of measurments =1.6-2.6% ). The measurements obtained from this study were more precise and accurate than any other data reported previously. However, the attention must be made on less recovery (39-40%) with thermostable enzyme. The results of efficacy trial indicated that weight gain and feed conversion ratio (FCR) were high with all enzyme added diets during feeding period compared to CON diet. The Phy-1000, however, provided significantly better FCR values than the rest of diets due to a marked reduction (P<0.05) in feed intake. Dry matter retention was significantly (P<0.05) high with Phy-500 diet. Weight (g) and relative weight (g/100 BW) of digestive tract was significantly (P<0.05) low with Phy-1000 and Phy-5000 diets. The length of digestive tract was significantly (P<0.05) high with Phy-500. The results indicated that the performance of quails and their digestive tract development were markedly influenced by the novel enzyme products.Â