Standardized Total Tract Digestibility Research Articles

Tail-end dehulling of canola meal improves apparent and standardized total tract digestibility of phosphorus when fed to growing pigs.

Tail-end dehulling of canola meal (CM) has been shown to reduce dietary fiber and increase crude protein content in the dehulled meal. The application of this procedure also increased the total and non-phytate P content in the dehulled meal. However, it is unclear if dehulling affects P digestibility in the different fractions (i.e., the dehulled meal and the coarse fraction) and if it differs when fed to growing pigs at two different BW. Therefore, two experiments were conducted to determine the apparent (ATTD) and standardized (STTD) total tract digestibility of P in dehulled CM fed to growing pigs. Diets containing non-dehulled regular canola meal (RCM), and two fractions produced using sieve size of 355 µm: a low-fiber high-protein fraction (dehulled canola meal [DCM]) and a high-fiber low-protein fraction (coarse canola meal [CCM]) as the only source of P were fed to growing pigs at two different BW. A total of 48 pigs were used for the two experiments. In experiment 1, 24 barrows [(Yorkshire × Landrace) × Duroc] with initial BW of 24.5 ± 1.68 kg were individually housed in metabolism crates and fed the experimental diets for 10 d for total fecal collection. In experiment 2, 24 barrows with an average initial BW of 73.8 ± 4.93 kg were used; experimental diets and fecal collection procedures were the same as in experiment 1. Each experiment used six replicates per treatment. A P-free diet was used to determine basal endogenous losses of P (139.6 ± 10.7 and 150.89 ± 20.1 mg/kg of DMI for experiments 1 and 2, respectively). Data were analyzed as a completely randomized design. In experiment 1, the ATTD and STTD of P were greater (P < 0.05) for DCM (42.4% and 46.1%) than for the RCM (32.0% and 35.7%) and CCM (24.5% and 28.4%) diets. In experiment 2, the ATTD and STTD of P were greater (P < 0.05) for DCM (38.7% and 42.8%) than for the CCM diet (22.6% and 26.8%); whereas the values for RCM diet were intermediate (31.0% and 35.0%) and not different from the DCM and CCM. In conclusion, dehulling canola meal increased ATTD and STTD of P in growing pigs of different BW; however, there was no effect of BW.

Additivity of values for phosphorus digestibility in corn, soybean meal, and canola meal in diets fed to growing pigs.

ObjectiveThis study was conducted to determine the apparent and standardized total tract digestibility (ATTD and STTD) of phosphorus (P) in corn, soybean meal (SBM), and canola meal (CM), and additivity of values for ATTD and STTD of P in corn, SBM, and CM in diets fed to growing pigs.MethodsThirty-six growing barrows (initial body weight of 21.6±1.7 kg) were placed in metabolism crates and allotted to a completely randomized design with 6 diets and 6 pigs per diet. Six diets were formulated using corn, SBM or CM as the sole source of P, or corn and SBM, or corn and CM, or corn, SBM, and CM as the P source in each diet, respectively. Fecal samples were collected for 5 d following a 7 d adaptation period to the diets.ResultsValues for ATTD and STTD of P in corn, SBM, and CM in growing pigs were 33.12% and 37.76%, 50.19% and 56.62%, 34.93% and 39.45%, respectively. The ATTD and STTD of P in SBM were greater (p<0.05) than those in corn and CM. However, there were no differences in the ATTD or STTD of P between corn and CM. The determined STTD of P in the mixture of corn and SBM, corn and CM, and corn, SBM, and CM is not different from the calculated STTD values.ConclusionValues for STTD of P in corn, SBM, and CM are additive in their mixture fed to growing pigs.

Inclusion of excess dietary calcium in diets for 100- to 130-kg growing pigs reduces feed intake and daily gain if dietary phosphorus is at or below the requirement.

An experiment was conducted to test the hypothesis that the requirement for standardized total tract digestible (STTD) Ca by pigs from 100 to 130 kg depends on the concentration of STTD P in the diet. Ninety pigs (average initial BW: 99.89 ± 3.34 kg) were randomly allotted to 15 experimental diets. Each diet was fed to 6 replicate pigs using a randomized complete block design. Fifteen corn and soybean meal-based diets were formulated and phytate and Na were constant among treatments. Diets were formulated using a 3 × 5 factorial design with diets containing 0.11%, 0.21%, or 0.31% STTD P and 0.12%, 0.29%, 0.46%, 0.61%, or 0.78% total Ca (0.08%, 0.18%, 0.29%, 0.38%, or 0.49% STTD Ca). The P concentrations ranged from 48 to 152% of the STTD P requirement for 100- to 125-kg pigs and the Ca concentrations ranged from 27 to 173% of the total Ca requirement. Experimental diets were fed for 28 d and pigs were individually housed. Pig and feeder weights were recorded at the beginning and at the conclusion of the experiment to calculate ADFI, ADG, and G:F. On d 28, all pigs were euthanized and the right femur was extracted. Ash, Ca, and P concentrations were determined from the de-fatted, dried femurs. Results indicated that as dietary concentrations of STTD Ca increased, ADFI decreased (main effect of Ca, < 0.05), regardless of the dietary concentration of P. The model to predict ADFI (ADFI = 3.6782 - 1.2722 × STTD Ca [%]; = 0.001) was dependent only on the concentration of dietary STTD Ca, but not on the concentration of dietary STTD P. In contrast, the model to predict ADG depended on both STTD Ca and STTD P (1.4556 - 1.4192 × STTD Ca [%] - 1.0653 × STTD P [%] + 4.2940 STTD Ca [%] × STTD P [%]; = 0.002). There were no effects of STTD Ca or STTD P on G:F. Linear increases were observed for bone ash, bone Ca, and bone P as dietary concentrations of STTD Ca increased for all concentrations of STTD P, but the increase was greater at the greatest concentration of STTD P than at lower concentrations (interaction, < 0.001). In conclusion, results indicate that the estimated requirement for dietary STTD Ca by 100- to 130-kg pigs needed to maximize ADG, bone ash, and bone Ca depends on the concentration of STTD P in the diet. Results also indicate that feeding Ca in excess of the current requirement for total Ca is detrimental to growth performance of pigs from 100 to 130 kg unless P is also included above the requirement.

Amino acid and phosphorus digestibility of fermented corn-soybean meal mixed feed with Bacillus subtilis and Enterococcus faecium fed to pigs1

In the present study, a 2-stage solid-state fermentation process using followed by was performed with the purpose of improving the nutritional quality of corn and soybean meal (SBM) mixed feed (MF). The matrix of native MF and fermented MF (FMF) was analyzed using scanning electron microscopy to determine external structures after solid-state fermentation. Results of the present study indicated that the FMF had a greater concentration of CP and total P compared with the unfermented feed, whereas the contents of β-conglycinin, glycinin, phytate P, raffinose, stachyose, and NDF in FMF declined by 77.6, 86.7, 41.2, 47.2, 36.6, and 38.9%, respectively. The content of trichloroacetic acid-soluble protein, particularly those of small peptides and free AA, increased more than 3 times after fermentation. Scanning electron microscopy revealed that irregular shapes and a lot of porous structures were observed in the SBM of FMF, the cell wall of corn in FMF was destroyed, and the number of starch granules was decreased after 2-stage fermentation. Two animal experiments were conducted to evaluate the digestibility of CP and P in FMF when fed to pigs. In Exp. 1, 6 barrows (15.20 ± 1.27 kg initial BW) fitted with a T-cannula in the distal ileum were allotted to a replicated 3 × 3 Latin square with 3 diets and 3 periods per square. Two diets containing unfermented MF or FMF as the only source of protein and a N-free diet were formulated. Results indicated that the apparent ileal digestibility (AID) of total AA and Lys in FMF (74.98 and 75.34%) were greater ( < 0.05) than in untreated MF (69.66 and 68.56%). The standard ileal digestibility (SID) of Lys in FMF (82.17%) was also greater ( < 0.05) than in MF (75.91%). In Exp. 2, 16 barrows (17.57 ± 1.08 kg initial BW) were allotted to 2 diets formulated to contain MF or FMF as the sole source of P to determine the digestibility of P. The apparent total tract digestibility and standardized total tract digestibility of P in FMF were 58.14 and 64.72%, respectively. These values were greater ( < 0.01) than in untreated MF (37.11 and 44.89%, respectively). Our results indicate that a solid-state fermentation process using followed by offers an effective approach to improving the quality of corn and SBM MF.

Effects of graded levels of microbial phytase on apparent total tract digestibility of calcium and phosphorus and standardized total tract digestibility of phosphorus in four sources of canola meal and in soybean meal fed to growing pigs.

One hundred twenty pigs were used to determine effects of graded levels of microbial phytase on the apparent total tract digestibility (ATTD) of P and Ca and the standardized total tract digestibility (STTD) of P in 4 sources of canola meal and in 1 source of soybean meal (SBM) fed to growing pigs. The 4 sources of canola meal were produced from 1 source of high-protein canola seeds and 2 sources of conventional canola seeds with 1 of the conventional canola seeds being divided into 2 separate batches before crushing. Pigs (16.2 ± 5.3 kg initial BW) were individually housed in metabolism crates and were randomly allotted to 1 of 20 diets in a 5 × 4 factorial arrangement of treatments with 5 ingredients and 4 levels of phytase. There were 6 replicate pigs per diet. Five basal diets based on high-protein canola meal (CM-HP), high-temperature processed canola meal (CM-HT), low-temperature processed canola meal (CM-LT), conventional canola meal (CM-CV), or SBM were formulated. The basal diets contained no phytase. Fifteen additional diets were prepared by adding approximately 500, 1,500, or 2,500 phytase units/kg to each of the 5 basal diets. Feces were quantitatively collected for 5 d based on the marker-to-marker approach after a 7-d adaptation period. Results indicated that supplementation of microbial phytase increased (linear, < 0.05) the ATTD of Ca in diets containing CM-HP, CM-HT, CM-CV, and SBM but not in diets containing CM-LT. Microbial phytase also increased (linear and quadratic, < 0.05) the ATTD and STTD of P in all 5 ingredients. Compared with the CM-CV diets, the CM-HP diets had greater ( < 0.05) ATTD of Ca. The ATTD of Ca in the SBM diet was greater ( < 0.05) than in all canola meal diets, but no differences were observed in ATTD of Ca between CM-HT and CM-LT diets. The ATTD and the STTD of P were less ( < 0.05) in CM-HP, CM-HT, CM-LT, or CM-CV than in SBM if no microbial phytase was added, but no differences were observed in the ATTD and STTD of P in SBM, CM-HP, CM-HT, or CM-CV if the highest amount of phytase were added (interaction, < 0.05). Regression equations were developed to calculate the response to microbial phytase on the STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM. In conclusion, inclusion of graded levels of microbial phytase increased the ATTD and STTD of P in CM-HP, CM-HT, CM-LT, CM-CV, and SBM and the response to microbial phytase added to each ingredient can be predicted by regression equations.

Standardized total tract digestibility of phosphorus in various inorganic phosphates fed to growing pigs

An experiment was conducted to determine the standardized total tract digestibility (STTD) of phosphorus (P) in five sources of inorganic phosphate fed to growing pigs, including dicalcium phosphate (DCP), monodicalcium phosphate (MDCP), monocalcium phosphate (MCP), tricalcium phosphate (TCP) and monosodium phosphate (MSP, reagent grade). Six barrows (42.4±1.1kg) individually housed in metabolism crates were allotted to a 6×6 Latin square design with six dietary treatments and six periods. Each experimental period consisted of a 4day adaptation period and a 5day collection period. The five experimental diets contained 0.24 to 0.34% of P from each inorganic phosphate as a sole source of P. A P-free diet was also prepared to estimate the basal endogenous loss of P. The STTD of P in MSP (94.9%) was not different from the STTD of P in MCP (93.0%), but was greater (P<0.05) than that in DCP, MDCP and TCP (87.0, 86.5 and 71.3%, respectively). In conclusion, digestibility of P in reagent-grade MSP was greater than that in feed-grade inorganic phosphates such as DCP, MDCP and TCP, and digestibility of P in DCP and MDCP was greater than that in the TCP.

178 Effects of zinc oxide and microbial phytase on standardized total tract digestibility of calcium in maize-based diets fed to growing pigs

178 Effects of zinc oxide and microbial phytase on standardized total tract digestibility of calcium in maize-based diets fed to growing pigs

199 Effect of tail-end dehulling of canola meal on apparent and standardized total tract digestibility of phosphorus when fed to growing pigs

199 Effect of tail-end dehulling of canola meal on apparent and standardized total tract digestibility of phosphorus when fed to growing pigs

Methodological aspects of determining phosphorus digestibility in swine: A review.

The role of phosphorus (P) in swine nutrition has been taken on new significance in recent years. Methods to determine the available phosphorus (AP) content of swine feeds include relative bioavailability (RBV), apparent total tract digestibility (ATTD), standardized total tract digestibility (STTD), and true total tract digestibility (TTTD). The RBV of P is determined by measuring bone ash or bone P, whereas the ATTD of P is determined by calculating the difference between P intake and P excretion in feces. Recent research has shown that the use of ATTD of P underestimates the AP due to the existence of endogenous P in feces and digesta. The STTD can be calculated from ATTD by taking basal endogenous phosphorus losses (EPL) into consideration. The basal EPL in pigs can be measured by feeding a P-free diet. Values for STTD of P are believed to be additive in mixed diets but not for ATTD of P. The regression method is a common approach to determine total EPL and TTTD of P, which measures the linear relationship between fecal P excretion and the dietary intake of total P. In addition, in vitro methods such as the bionic enzymatic method are being increasingly utilized because they can be done quickly and simply. Several dietary factors such as P and Ca concentrations, phytate, Ca to P ratio and vitamin D may affect AP. This review summarizes the evolution of methods to measure AP and factors that can affect AP, which may provide information to formulate swine diet more accurately. Moreover, the knowledge about AP may help to reduce the P waste in swine production and thus decrease its impact on the environment.

Coefficient of standardized total tract digestibility of phosphorus in oilseed meals and distillers dried grains in growing-finishing pigs

This study was conducted to determine the coefficient of total tract standardized digestibility (CTTSD) of phosphorus (P) in oilseed meals and distillers dried grains (DDG) fed to growing-finishing pigs. Twelve barrows (initial bodyweight (BW) standard deviation, 52.25 +/- 2.57 kg) were allocated individually to metabolism cages. The experimental design was a 12 x 8 incomplete Latin square with 12 dietary treatments and eight replication periods. The diets were formulated individually with dehulled soybean meal produced in Korea (SBM-KD), soybean meal produced in India (SBM-I), soybean meal produced in Korea (SBM-K), corn high-protein distiller dried grains (HPDDGs), tapioca distillers dried grains (TDDG), canola meal (CAM), corn germ meal (CGM), copra meal (CM), palm kernel meal (PKM), sesame meal (SM), perilla meal (PM), and a P-free diet. Intake of P was highest in SM and PM. Excretion of P was reduced in y ascending order as HPDDG, TDDG and CGM; SBM-K; and SM and PM. The CTTAD of P was higher in CGM than SBM-K, TDDG, SM and PM. HPDDG and CGM showed greater CTTSD of P than SBM-K, CAM and PM. Digestible concentration of P on CTTSD (CTTSD-P) of P was greater in PM and CAM than the others except for SBM-KD. In summary, PM could be utilized as an alternative feedstuff to SBM, but its usage is regarded only as a source of P. In addition, the results of the current study would provide valuable information for formulating pig feed with precise P utilization in ingredients using mixed diets

Standardized total tract digestibility of phosphorus in flaxseed meal fed to growing and finishing pigs without or with phytase supplementation.

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%.

Dose-dependent effects of a microbial phytase on phosphorus digestibility of common feedstuffs in pigs.

ObjectiveThe objective of this study was to evaluate increasing doses of a novel microbial phytase (Cibenza Phytaverse, Novus International, St. Charles, MO, USA) on standardized total tract digestibility (STTD) of P in canola meal (CM), corn, corn-derived distiller’s dried grains with solubles (DDGS), rice bran (RB), sorghum, soybean meal (SBM), sunflower meal (SFM), and wheat.MethodsTwo cohorts of 36 pigs each (initial body weight = 78.5±3.7 kg) were randomly assigned to 2 rooms, each housing 36 pigs, and then allotted to 6 diets with 6 replicates per diet in a randomized complete block design. Test ingredient was the only dietary source of P and diets contained 6 concentrations of phytase (0, 125, 250, 500, 1,000, or 2,000 phytase units [FTU]/kg) with 0.4% of TiO2 as a digestibility marker. Feeding schedule for each ingredient was 5 d acclimation, 5 d fecal collection, and 4 d washout. The STTD of P increased (linear or exponential p≤0.001) with the inclusion of phytase for all ingredients.ResultsBasal STTD of P was 37.6% for CM, 37.6% for corn, 68.6% for DDGS, 10.3% for RB, 41.2% for sorghum, 36.7% for SBM, 26.2% for SFM, and 55.1% for wheat. The efficiency of this novel phytase to hydrolyze phytate is best described with a broken-line model for corn, an exponential model for CM, RB, SBM, SFM, and wheat, and a linear model for DDGS and sorghum. Based on best-fit model the phytase dose (FTU/kg) needed for highest STTD of P (%), respectively, was 735 for 64.3% in CM, 550 for 69.4% in corn, 160 for 55.5% in SBM, 1,219 for 57.8% in SFM, and 881 for 64.0% in wheat, whereas a maximum response was not obtained for sorghum, DDGS and RB within the evaluated phytase range of 0 to 2,000 FTU/kg. These differences in the phytase concentration needed to maximize the STTD of P clearly indicate that the enzyme does not have the same hydrolysis efficiency among the evaluated ingredients.ConclusionVariations in enzyme efficacy to release P from phytate in various feedstuffs need to be taken into consideration when determining the matrix value for phytase in a mixed diet, which likely depends on the type and inclusion concentration of ingredients used in mixed diets for pigs. The use of a fixed P matrix value across different diet types for a given phytase concentration is discouraged as it may result in inaccurate diet formulation.

Effects of zinc oxide and microbial phytase on digestibility of calcium and phosphorus in maize-based diets fed to growing pigs.

An experiment was conducted to test the hypothesis that inclusion of Zn at a pharmacological level in diets fed to pigs affects apparent total tract digestibility (ATTD) of Ca and P and standardized total tract digestibility (STTD) of Ca. The second hypothesis was that inclusion of microbial phytase increases the ATTD of Ca and P and the STTD of Ca regardless of the concentration of Zn in the diet. Fifty-six growing barrows (15.4 ± 1.9 kg average BW) were allotted to a randomized complete block design with 7 dietary treatments and 8 pigs per treatment. A maize-based basal diet was formulated with either 0 or 2,400 mg/kg Zn from ZnO and 0, 1,000, or 3,000 units of phytase (FTU) per kilogram. A Ca-free diet was used to determine basal endogenous losses of Ca. Experimental diets were fed for 13 d, and feces were collected from the feed provided from d 6 to 11 using the marker-to-marker approach; urine was also collected from d 6 to 11. Retention of Ca, ATTD of Ca, and STTD of Ca increased ( < 0.01) as the concentration of phytase in the diet increased and were less ( < 0.01) if ZnO was used than if no ZnO was added to the diet. Retention of P and the ATTD of P increased ( < 0.0001) as the concentration of phytase increased in the diet, but the increase was greater if ZnO was not added than if ZnO was added to the diet (interaction, < 0.05). In conclusion, pharmacological levels of Zn reduced Ca and P digestibility and retention, but this effect was partly ameliorated by the inclusion of phytase in the diets. Inclusion of microbial phytase increased the ATTD and STTD of Ca in diets and also the ATTD of P.

Amino acid and phosphorus digestibility of fermented corn-soybean meal mixed feed with Bacillus subtilis and Enterococcus faecium fed to pigs.

In the present study, a 2-stage solid-state fermentation process using followed by was performed with the purpose of improving the nutritional quality of corn and soybean meal (SBM) mixed feed (MF). The matrix of native MF and fermented MF (FMF) was analyzed using scanning electron microscopy to determine external structures after solid-state fermentation. Results of the present study indicated that the FMF had a greater concentration of CP and total P compared with the unfermented feed, whereas the contents of β-conglycinin, glycinin, phytate P, raffinose, stachyose, and NDF in FMF declined by 77.6, 86.7, 41.2, 47.2, 36.6, and 38.9%, respectively. The content of trichloroacetic acid-soluble protein, particularly those of small peptides and free AA, increased more than 3 times after fermentation. Scanning electron microscopy revealed that irregular shapes and a lot of porous structures were observed in the SBM of FMF, the cell wall of corn in FMF was destroyed, and the number of starch granules was decreased after 2-stage fermentation. Two animal experiments were conducted to evaluate the digestibility of CP and P in FMF when fed to pigs. In Exp. 1, 6 barrows (15.20 ± 1.27 kg initial BW) fitted with a T-cannula in the distal ileum were allotted to a replicated 3 × 3 Latin square with 3 diets and 3 periods per square. Two diets containing unfermented MF or FMF as the only source of protein and a N-free diet were formulated. Results indicated that the apparent ileal digestibility (AID) of total AA and Lys in FMF (74.98 and 75.34%) were greater ( < 0.05) than in untreated MF (69.66 and 68.56%). The standard ileal digestibility (SID) of Lys in FMF (82.17%) was also greater ( < 0.05) than in MF (75.91%). In Exp. 2, 16 barrows (17.57 ± 1.08 kg initial BW) were allotted to 2 diets formulated to contain MF or FMF as the sole source of P to determine the digestibility of P. The apparent total tract digestibility and standardized total tract digestibility of P in FMF were 58.14 and 64.72%, respectively. These values were greater ( < 0.01) than in untreated MF (37.11 and 44.89%, respectively). Our results indicate that a solid-state fermentation process using followed by offers an effective approach to improving the quality of corn and SBM MF.

Effects of graded levels of microbial phytase on apparent total tract digestibility of calcium and phosphorus and standardized total tract digestibility of phosphorus in four sources of canola meal and in soybean meal fed to growing pigs

Effects of graded levels of microbial phytase on apparent total tract digestibility of calcium and phosphorus and standardized total tract digestibility of phosphorus in four sources of canola meal and in soybean meal fed to growing pigs

Requirement for digestible calcium by 25 to 50 kg pigs at different dietary concentrations of phosphorus as indicated by growth performance, bone ash concentration, and calcium and phosphorus balances.

Two experiments were conducted to determine the requirement for standardized total tract digestible (STTD) Ca by 25 to 50 kg pigs at different concentrations of STTD P. Twenty corn-soybean meal based diets were formulated with diets containing 4 concentrations of STTD P (0.15, 0.31, 0.39, or 0.47%) and 5 concentrations of STTD Ca (0.13, 0.27, 0.42, 0.57, or 0.72%). Diets were mixed in 1 batch and were used in both experiments. In Exp. 1, 240 pigs (initial average BW: 24.70 ± 1.27 kg) were randomly allotted to the 20 diets in 6 blocks with 1 pen per diet in each block using a 4 × 5 factorial design. There was 1 gilt and 1 barrow in each pen. At the conclusion of the 28 d experiment, all barrows were euthanized and the right femur was collected. Results indicated that there were interactions ( < 0.001) between concentration of STTD Ca and concentration of STTD P in diets for ADG, G:F, and bone ash. The predicted maximum ADG at STTD P concentrations of 0.15, 0.31, 0.39, and 0.47% were 0.76, 0.87, 0.90, and 0.92 kg at STTD Ca concentrations of 0.12, 0.36, 0.47, and 0.59%, respectively, which correspond to STTD Ca:STTD P ratios of 0.80:1, 1.16:1, 1.21:1, and 1.26:1. The predicted maximum G:F ratio at the 4 STTD P concentrations were 0.43, 0.46, 0.48, and 0.50 kg/kg at STTD Ca concentrations of 0.09, 0.38, 0.52, and 0.67%, respectively, and these values correspond to STTD Ca:STTD P ratios of 0.60:1, 1.23:1, 1.33:1, and 1.43:1. The predicted maximum bone ash at the 4 STTD P concentrations were 14.5, 21.0, 23.1, and 24.5 g at STTD Ca concentrations of 0.41, 0.56, 0.64, and 0.72%, respectively, which correspond to STTD Ca:STTD P ratios of 2.73:1, 1.81:1, 1.64:1, and 1.53:1. In Exp. 2, 120 pigs (initial average BW: 29.45 ± 2.15 kg) were placed in metabolism crates and randomly allotted to the 20 diets in 6 blocks with 1 pig per diet in each block. Fecal and urine samples were collected. Results indicated that the predicted maximum retention of Ca in the body at STTD P concentrations of 0.15, 0.31, 0.39, and 0.47% were 4.7, 7.1, 8.6, and 10.2 g/d at STTD Ca concentrations of 0.77, 0.96, 1.06, and 1.15%, respectively, which correspond to STTD Ca:STTD P ratios of 5.13:1, 3.10:1, 2.72:1, and 2.45:1. These observations indicate that if STTD P meets or exceeds the requirement, the STTD Ca:STTD P ratio needed to maximize ADG and G:F by 25 to 50 kg pigs is between 1.16:1 and 1.43:1. However, a greater ratio may be needed to maximize bone ash or Ca retention.

0926 New bacterial 6-phytase expressed in Pseudomonas fluorescens improved growth performance, bone parameters, and P digestibility in growing pigs

A study was conducted to determine the effects of a new bacterial 6-phytase expressed in Pseudomonas fluorescens (CIBENZA® PHYTAVERSE®, Novus International, Inc., St Charles, MO) on growth performance, bone parameters, and P digestibility in growing pigs fed a diet deficient in standardized total tract digestible (STTD) P. A total of 144 pigs (initial BW = 44.27 ± 0.74 kg) were randomly allotted to 1 of 4 treatments with 18 replications and 2 pigs/pen. Treatments included 1) a positive control (POS) that met the requirements (NRC, 2012) for all nutrients, 2) a negative control (NEG) deficient only in STTD P (−0.10% vs. POS), 3) NEG supplemented with 250 FTU/kg phytase (NEG+250), and 4) NEG supplemented with 500 FTU/kg phytase (NEG+500). Data were analyzed using the Mixed Procedure (SAS® Institute, Cary, NC). The ADG and G:F was less (P < 0.01) for pigs consuming the NEG diet compared with POS (0.964 vs. 1.093 kg and 0.356 vs. 0.387, respectively). The ADG of pigs consuming NEG+250 or NEG+500 was not different (P > 0.05) from that of pigs consuming POS (1.061 or 1.066 vs. 1.093, respectively). Phytase linearly (P < 0.01) improved the ADG of pigs fed the NEG diet. The G:F of pigs fed NEG+250 or NEG+500 was not different from pigs fed the POS. Phytase supplementation to the NEG diet tended (P = 0.06) to linearly improve the G:F of pigs. Bone ash weight and bone P weight were greater for pigs fed the POS diet than for pigs fed the NEG diet (6.42 vs. 4.70 g and 1.19 vs. 0.86 g, respectively). Supplementing pigs with either 250 or 500 FTU/kg, however, linearly improved (P < 0.01) bone ash weight compared with pigs fed NEG (4.70 vs. 5.63 or 5.99 g, respectively). Likewise, bone P weight was linearly increased (P < 0.01) in pigs fed NEG+250 (1.04 g) or NEG+500 (1.11 g) compared with pigs fed NEG (0.86 g). The STTD of P was greater (P < 0.05) for pigs fed NEG+500 (48.71%) that all other treatments, with the NEG being the least digestible (35.03%). In conclusion, this new phytase efficiently improved the growth performance, bone parameters, and STTD of P in grower pigs.

0924 Effects of microbial phytase on the apparent and standardized total tract digestibility of calcium in milk co-products fed to growing pigs

0924 Effects of microbial phytase on the apparent and standardized total tract digestibility of calcium in milk co-products fed to growing pigs

0479 Determination of standardized total tract digestibility of phosphorus in flaxseed meal fed to finishing pigs without or with phytase supplementation

0479 Determination of standardized total tract digestibility of phosphorus in flaxseed meal fed to finishing pigs without or with phytase supplementation

High dose of phytase on apparent and standardized total tract digestibility of phosphorus and apparent total tract digestibility of calcium in canola meals from Brassica napus black and Brassica juncea yellow fed to growing pigs

A total of 42 barrows weighing 19.8 ± 1.22 kg were fed seven diets to give six replicates per treatment. The experiment was conducted in a factorial arrangement with factors being (1) two canola meals (CM) types and (2) three phytase levels (0, 500, and 2500 FTU kg−1). The basal endogenous phosphorus (P) losses and standardized total tract digestibility (STTD) was calculated using the P-free method. There was no effect of CM types on feed intake and fecal P output, but an interaction effect was observed for P intake (CM × phytase; P &lt; 0.05). Supplementation of phytase (2500 FTU kg−1) reduced (P &lt; 0.001) fecal P output (g d−1), and the output was reduced by 58% in Brassica napus black (BNB) and 64% in Brassica juncea yellow (BJY) diets. Supplementation of phytase improved (P &lt; 0.001) both apparent total tract digestibility (ATTD) and STTD of P in both BNB and BJY, regardless of dose. The basal endogenous P loss (EPL) was determined to be 111.28 ± 35.09 mg kg−1 of dry matter intake (DMI). There was no further improvement in STTD of P when phytase was increased from 500 to 2500 FTU kg−1 in both CM types. The ATTD of calcium (Ca) was increased (P &lt; 0.001) in BNB and BJY when phytase was supplemented at 500 and 2500 FTU kg−1. The results, therefore, indicate that supplementation of phytase at 500 FTU kg−1 improved both ATTD and STTD of P in two CM types, but a super dose of 2500 FTU kg−1 had no additional benefit. Similarly, ATTD of Ca was increased when phytase was supplemented at 500 FTU kg−1 without further improvement at 2500 FTU kg−1.