Measurement of total tract retention of phosphorus in several feedstuffs of plant origin for broiler chickens: effect of microbial phytase

An experiment was conducted to compare the true total tract retention of phosphorus (P) in soybean meal, canola meal, cottonseeds meal, peanut meal, corn distiller's dried grains with soluble (DDGS), wheat bran, wheat grain, and wheat shorts with or without phytase addition. A total of 576 male Arbour Acres broilers aged 23 days of similar live weight were randomly assigned into 16 treatments with 6 replicates each and 6 birds in each replicate. Sixteen diets were designed by combining 2 factors that include 8 ingredients and phytase level (0 or 1000 FTU/kg). Dietary P was only provided by the ingredient to be tested. A purified P-free diet was prepared to determine endogenous P loss (EPL). The retainability of P was evaluated by collecting an excreta trial. The results showed that basal EPL was 97.45 mg/DMI. The true retainability of P in soybean meal, canola meal, cottonseed meal, and DDGS was 53.90%, 53.22%, 54.73%, and 49.45%, respectively, much higher than peanut meal (42.76%), wheat bran (38.26%), wheat grain (36.77%), and wheat shorts (36.95%). Phytase significantly increased apparent or true retainability of P (p < .05). Phytase showed the greatest improvement of retainability of P for wheat ingredients (wheat shorts 41.35%; wheat grain 41.34%; wheat bran 35.94%) and soybean meal (31.52%), followed by canola meal (23.07%), cottonseed meal (14.43%), peanut meal (11.51%), and DDGS (10.23%). The retainable P equivalent of 1000 FTUs of microbial phytase corresponding to ingredients was between 0.4 g (DDGS and peanut meal) and 1.3 g (wheat bran).