Effect of Microbial Phytase on Digestibility of Phosphorus in Seven Sources of Sunflower co-Products Fed to Growing Pigs.

An experiment was conducted to test the hypothesis that there are no differences among sources of sunflower co-products on the apparent total tract digestibility (ATTD) of P and Ca and on the standardized total tract digestibility (STTD) of P regardless of where the ingredients were produced. Six sources of sunflower meal (SFM) were obtained from the U.S. (2 sources), Ukraine (2 sources), Hungary, and Italy. A source of sunflower expellers (SFE) from the U.S. was also used. Seven diets were formulated by mixing each source of sunflower co-product with cornstarch; therefore, the sunflower co-product was the only source of P in these diets. Seven additional diets that were similar to the previous seven diets with the exception that 300 units per kg of microbial phytase were added were also formulated. A total of 112 barrows (initial body weight = 17.95 kg ± 1.37 kg) were allotted to the 14 diets using 4 blocks, 2 pigs per diet in each block, and a total of 8 replicate pigs per diet. Pigs were placed in individual metabolism crates to allow for the total collection of fecal materials for 4 days after 7 days of adaptation to the diets. Diets and dried fecal samples were analyzed for dry matter, Ca, and P. Data for Ca and P digestibility were analyzed in a randomized complete block design in a 7 × 2 factorial arrangement using the PROC MIXED function in SAS. Results indicated that diets containing phytase had greater (P < 0.01) ATTD of Ca and P and greater (P < 0.01) STTD of P than diets without phytase (Table 1). Digestibility of P was also greater in one of the sources of SFM from Ukraine compared with the other sources except for the SFM from Hungary (Table 2). Pigs fed the diet containing one of the sources of SFM from the U.S. had greater (P < 0.05) ATTD of Ca compared with pigs fed diets containing the other source of SFM from the U.S. or one of the Ukraine SFM sources. In conclusion, some variability in the ATTD and STTD of P and the ATTD Ca was observed among SFM of different origins, but the ATTD and STTD of P and ATTD of Ca in SFM and SFE were greater if microbial phytase was used. [ABSTRACT FROM AUTHOR]