Exogenous phytase activity in the gastrointestinal tract of broiler chickens

The aim of the study was to utilize Western blot and activity stain to detect the activity of phytase in different gastrointestinal segments of broiler chickens fed diets containing exogenous phytase. Three hundred day-old broilers (Arbor Acres) were selected and randomly allocated to three dietary treatment groups, with 12 replicates per treatment group. Two-phased diets were used. The grower and finisher diet was fed from 0 to 3 weeks and 4 to 6 weeks of age, respectively. A control diet containing adequate nonphytate phosphorus (NPP) was formulated. The control diet was reformulated to contain I g less NPP per kg diet to which 0 (low-NPP diet) or 750 U (phytase diet) of exogenous phytase per kg diet was added. Broilers fed the low-NPP diet gained weight slower (P < 0.05) than the other treatment groups. However, broilers fed the control diet gained weight at a rate similar (P > 0.05) to those fed the phyrase diet. The normal spectrophotometer method failed to detect exogenous phytase activity in the diet or in the digesta of broiler chickens fed the phytase diet. Exogenous phytase protein was detected in the phytase diet as well as in the digesta of crop, gizzard, duodenum and jejunum of broiler chickens fed the phytase diet. On the other hand, the activity stain detected phytase protein in all gastrointestinal segments with the exception of jejunum and ileum. The result of the study suggests that phytase activity in the digesta of the broiler gastrointestinal tract resulting from exogenous phytase supplementation in the diet can be detected and quantified by the Western blot and activity stain. (C) 2004 Elsevier B.V. All rights reserved.