The presence of inositol phosphates in gastric pig digesta is affected by time after feeding a nonfermented or fermented liquid wheat- barley-based diet

TY - JOUR

T1 - The presence of inositol phosphates in gastric pig digesta is affected by time after feeding a nonfermented or fermented liquid wheat- barley-based diet

AU - Blaabjerg, Karoline

AU - Jørgensen, H.

AU - Tauson, Anne-Helene

AU - Poulsen, H.D.

PY - 2011/10

Y1 - 2011/10

N2 - The objective was to quantify the retention of digesta and evaluate the degradation of phytate or inositol hexakisphosphate (InsP 6) and lower inositol phosphates (InsP 5, InsP 4, InsP 3, and InsP 2) in the stomach at different times after feeding pigs a fer- mented liquid diet with microbial phytase or a non- fermented diet with or without microbial phytase. Six barrows fitted with gastric cannulas were used. The experiment was a 3 × 3 Latin square with 3 pigs fed 3 diets during 3 wk in 2 replicates. Each experimental period lasted for 7 d, comprising 3 d of adaptation and 4 d of total collection of gastric digesta. For each pig, the digesta was collected once daily at 1, 2, 3, or 5 h af- ter feeding the morning meal. A basal wheat- and bar- ley-based diet was steam-pelleted at 90°C. The dietary treatments were a nonfermented basal diet (NF-BD), the NF-BD with microbial phytase (750 phytase units of phytase/kg, as-fed basis; NF-BD + phytase), and the NF-BD + phytase fermented for 17.5 h (F-BD + phy- tase). Gastric InsP 6-P was not detected at all in pigs fed F-BD + phytase because of complete InsP 6 degra- dation during fermentation of the feed before feeding. Gastric InsP 6-P decreased over time (P < 0.05) in pigs fed NF-BD and NF-BD + phytase. The decreases were 45, 54, 56, and 61 percentage points greater at 1, 2, 3, and 5 h, respectively, in pigs fed NF-BD + phytase compared with NF-BD. However, substantial amounts of InsP 6 still passed into the small intestine in pigs fed NF-BD + phytase, especially within the first hour (es- timated to 17% of InsP 6-P intake). The accumulation of lower inositol phosphates in gastric digesta was very small for all treatments and at all times because of a rapid and almost complete degradation. In conclusion, phytase addition to the nonfermented diet increased the degradation of gastric InsP 6. However, considerable amounts of intact InsP 6 still passed into the small in- testine because of a shortage of time for InsP 6 degrada- tion in the stomach. Therefore, to increase the apparent digestibility of plant P in dry wheat- and barley-based diets, the development of phytases that can degrade InsP 6 effectively immediately after ingestion of the feed at an initial gastric pH from 6.5 to 5.0 is needed. Feeding F-BD + phytase compensated for the shortage of time because the InsP 6 degradation was completed during fermentation before feeding. The degradation of InsP 6 to InsP 5 is the bottleneck for plant P utilization in pigs because the degradation of the lower inositol phosphates is rapid and almost complete.

AB - The objective was to quantify the retention of digesta and evaluate the degradation of phytate or inositol hexakisphosphate (InsP 6) and lower inositol phosphates (InsP 5, InsP 4, InsP 3, and InsP 2) in the stomach at different times after feeding pigs a fer- mented liquid diet with microbial phytase or a non- fermented diet with or without microbial phytase. Six barrows fitted with gastric cannulas were used. The experiment was a 3 × 3 Latin square with 3 pigs fed 3 diets during 3 wk in 2 replicates. Each experimental period lasted for 7 d, comprising 3 d of adaptation and 4 d of total collection of gastric digesta. For each pig, the digesta was collected once daily at 1, 2, 3, or 5 h af- ter feeding the morning meal. A basal wheat- and bar- ley-based diet was steam-pelleted at 90°C. The dietary treatments were a nonfermented basal diet (NF-BD), the NF-BD with microbial phytase (750 phytase units of phytase/kg, as-fed basis; NF-BD + phytase), and the NF-BD + phytase fermented for 17.5 h (F-BD + phy- tase). Gastric InsP 6-P was not detected at all in pigs fed F-BD + phytase because of complete InsP 6 degra- dation during fermentation of the feed before feeding. Gastric InsP 6-P decreased over time (P < 0.05) in pigs fed NF-BD and NF-BD + phytase. The decreases were 45, 54, 56, and 61 percentage points greater at 1, 2, 3, and 5 h, respectively, in pigs fed NF-BD + phytase compared with NF-BD. However, substantial amounts of InsP 6 still passed into the small intestine in pigs fed NF-BD + phytase, especially within the first hour (es- timated to 17% of InsP 6-P intake). The accumulation of lower inositol phosphates in gastric digesta was very small for all treatments and at all times because of a rapid and almost complete degradation. In conclusion, phytase addition to the nonfermented diet increased the degradation of gastric InsP 6. However, considerable amounts of intact InsP 6 still passed into the small in- testine because of a shortage of time for InsP 6 degrada- tion in the stomach. Therefore, to increase the apparent digestibility of plant P in dry wheat- and barley-based diets, the development of phytases that can degrade InsP 6 effectively immediately after ingestion of the feed at an initial gastric pH from 6.5 to 5.0 is needed. Feeding F-BD + phytase compensated for the shortage of time because the InsP 6 degradation was completed during fermentation before feeding. The degradation of InsP 6 to InsP 5 is the bottleneck for plant P utilization in pigs because the degradation of the lower inositol phosphates is rapid and almost complete.

U2 - 10.2527/jas.2010-3358

DO - 10.2527/jas.2010-3358

M3 - Journal article

SN - 0021-8812

VL - 89

SP - 3153

EP - 3162

JO - Journal of Animal Science

JF - Journal of Animal Science

IS - 10

ER -