title: Standardized total tract digestibility of phosphorus in flaxseed meal fed to growing and finishing pigs without or with phytase supplementation.
abstract: Two experiments were conducted to determine the apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of P in flaxseed meal (FM) and the effect of dietary microbial phytase on the digestibility of P in FM fed to growing and finishing pigs. In Exp. 1, eighteen growing barrows (26.6 ± 1.8 kg BW) were allotted to 1 of 3 experimental diets consisting of a diet containing 32% FM that was fed with or without phytase at 500 phytase units (FTU/kg and a P-free diet in a completely randomized design to give 6 replicates per diet. The experimental period lasted 12 d including first 7 d for adaptation and 5 d for total collection of feces. Pigs were fed their assigned diets at 4% of BW at the beginning of the experiment. The daily feed allowance was offered in 2 equal portions at 0800 and 1600 h. All experimental diets were provided in mash form. Results indicated that pigs fed the diets containing FM with dietary phytase had less ( < 0.05) fecal P concentration and daily P output than those fed the diets without phytase supplementation. Also, phytase supplementation increased ( < 0.05) the ATTD of P of the diets containing FM from 37.3% to 51.8% and STTD of P of the diets containing FM from 43.2% to 57.7%. The basal endogenous P losses (EPL) was calculated at 140 ± 11 mg/kg of DMI in growing pigs fed the P-free diet. In Exp. 2, eighteen finishing pigs (78.7 ± 2.4 kg BW) were randomly allotted to 1 of 3 dietary treatments. The experimental diets and procedures were similar to those described in Exp. 1. Similar to Exp. 1, pigs fed FM diets with phytase supplementation had less ( < 0.05) P concentration in feces than those fed diets without phytase supplementation. Also, daily P output was reduced ( = 0.08) when pigs were fed the FM diets with phytase compared to those fed the FM diets without phytase. The ATTD of P in FM diets was increased ( < 0.01) from 31.4% to 45.8%, whereas the STTD of P in FM diets was increased ( < 0.01) from 37.8% to 52.3% as a result of phytase supplementation. The basal EPL was calculated at 164 ± 19 mg/kg of DMI in finishing pigs fed the P-free diet. In conclusion, the ATTD and STTD of P in FM fed to growing pigs were 37.3% and 43.2%, respectively, whereas respective values for finishing pigs were 31.4%, and 37.8%, respectively. Also, dietary phytase supplementation improved both ATTD and STTD of P in FM for both stages of pigs by an average of 33%.
authors.forename: J W
authors.initials: JW
authors.lastname: Kim
authors.forename: S P
authors.initials: SP
authors.lastname: Ndou
authors.forename: G A
authors.initials: GA
authors.lastname: Mejicanos
authors.forename: C M
authors.initials: CM
authors.lastname: Nyachoti
mesh_terms: D010832:6-Phytase / Q000008:administration & dosage / Q000494:pharmacology*; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D004032:Diet / Q000662:veterinary*; D019587:Dietary Supplements; D004063:Digestion / Q000187:drug effects; D005243:Feces; D019597:Flax / Q000737:chemistry*; D041981:Gastrointestinal Tract / Q000187:drug effects; D016226:Phosphorus, Dietary / Q000008:administration & dosage* / Q000378:metabolism / Q000494:pharmacology; D013552:Swine / Q000502:physiology*
chemical_list: D016226:Phosphorus, Dietary; D010832:6-Phytase