Standardized and true total tract phosphorus digestibility in canola meals (Brassica napus black and Brassica juncea yellow) fed to growing pigs
Acharya Adhikari, Pratima
Two experiments were conducted to determine the apparent (ATTD), standardized (STTD) and true total tract digestibility (TTTD) of phosphorus (P) and ATTD of calcium (Ca) in Brassica napus black (BNB) and Brassica juncea yellow (BJY) canola meal (CM) fed to growing pigs. In Experiment 1, eight semi-purified diets containing graded levels of P i.e., 0.8, 1.6, 2.4 and 3.3 g/kg of DM, from either BNB or BJY, were fed to growing pigs with an initial BW of 19.9 ± 0.22 kg (mean ± SEM) in a randomized complete block design. The total and basal EPL estimated with the regression analysis and P-free diet methods were 665 ± 0.03 and 209 ± 96 mg/kg of DMI, respectively. The TTTD and STTD of P were determined to be 33.3 and 31.0% for BNB and 32.0 and 28.3% for BJY, respectively. In Experiment 2, the effect of high level of phytase supplementation on the ATTD of P and Ca and STTD of P in growing pigs was studied. Forty-two growing pigs with an initial BW of 19.8 ± 1.22 kg (mean ± SEM) were randomly allocated to 7 dietary treatments with 6 pigs per treatment according to a completely randomised design in a factorial arrangement with the factors being: 1) 2 types of CM (BNB and BJY) and 2) 3 levels of phytase (i. e., 0, 500 and 2,500 U/kg). The ATTD of P increased from 39.1 to 69.3, and 78.0% in BNB and from 46.0 to 71.4, and 78.0% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg, respectively. The STTD of P increased from 40.0 to 70.0, and 78.3% in BNB, and from 46.3 to 72.1, and 78.5% in BJY as phytase levels were added at 0, 500 and 2,500 U/kg. The basal EPL estimate was 117 ± 23.4 mg/kg DMI. Fecal P excretion in BNB and BJY were reduced by average value of 50.3 and 61.0% with the addition of both 500 and 2,500 FTU phytase II respectively. Results from these two experiments show that the values obtained for STTD and TTTD of P in BNB and BJY were similar.