A Comparison of the Test Tube and the Dialysis Tubing in Vitro Methods for Estimating the Bioavailability of Phosphorus in Feed Ingredients for Swine

Abstract

The validity of a simplified in vitro test tube (TT) method was compared with a more complicated dialysis tubing (DT) method to estimate the percentage of available phosphorus (P) in 41 plant origin and five animal origin feed ingredients for swine. The TT method using 1.0 or 0.25 g samples was compared with the DT method using 1.0 g samples at two pancreatic incubation times (2 vs 4 h) in a 3 x 2 factorial arrangement of treatments. Each DT and TT method treatment was replicated three and six times, respectively. Both methods utilize three enzymatic digestions: (i) predigestion with endoxylanase and beta-glucanase for 1 h, (ii) pepsin digestion for 2 h, and (iii) pancreatin digestion for 2 or 4 h. For the TT method, the entire procedure was conducted in a 50 mL conical centrifuge tube and replicated six times. For the DT method, the first two digestions were conducted in a 10 mL plastic syringe before the contents were quantitatively transferred into a segment of DT for the pancreatic digestion. The percentages of hydrolyzed P for plant origin ingredients measured by the DT method using 1.0 g samples and the TT method using 0.25 g samples were highly correlated (r = 0.94-0.97, P < 0.001) with each other and with published in vivo available P values for swine. Repeatabilities for these two methods ranged from 99.64 to 99.86%. The TT method using 1.0 g samples, however, did not provide valid estimates of P availability for all ingredients. For animal origin ingredients, neither method was significantly correlated (r = 0.1-0.6, P >or = 0.4) with published in vivo available P values. In conclusion, the accuracy and validity of the TT method using 0.25 g samples with a 2 h pancreatic digestion time was equal to or superior to the DT method using 1.0 g samples with a 4 h pancreatic digestion time for estimating P availability in plant origin feed ingredients.

Effect of ensiling treatment on secondary compounds and amino acid profile of tropical forage legumes, and implications for their pig feeding potential

“…To cross‐check these findings, the hydrolysable P was determined in vitro . For the three forage species which were highest in total phytates, and their silages (Table ), the resulting elevated P digestibility of >76 % conforms well with the values published by Bollinger et al for alfalfa meal ( Medicago sativa ) . The P digestibility is clearly superior to legume and cereal grains; maize, for example, is a typical tropical feed ingredient with 10–47% P digestibility depending on hybrid.…”

“…These IP2, IP3 and IP4 may also pass the column in the purification step, and may be accounted for total phytates. However, they hardly affect phosphorus retention, as was discussed by Lehrfeld and Morris for another method. This may also explain the calculated disproportion of phytate‐P (as inositol hexaphosphate (IP6)) to total P, the ratio often being >1.0 for the forages of our study.…”

Influence of Fungicide Residues in Wine Quality

“…and factors inherent to the individual (age, gender, genetic endowment, health, nutritional status, lifestyle, major route of absorption, etc.) (Fait & Colosio, 1998;Bollinger et al, 2005). Bioavailability is essentially a pharmaceutical term which refers to the portion of the dose of a drug administered exogenously that reaches the organ or tissue in which it carries out its action.…”

Validation of an in vitro method for the estimation of apparent total tract digestibility of phosphorus in plant feed ingredients for pigs

“…The method is based on Liu et al (1998) and Bollinger et al (2004Bollinger et al ( , 2005. Relevant modifications were identified (Roulin et al, 2008): a preliminary soaking step was introduced to imitate initial in vivo pH decrease and enabling endogenous phytase activity when present; an enzymatic preparation was also included, mainly for the cleavage of polysaccharides (␤-glucanase and endo-xylanase), but also for its hemicellulase, cellulase and proteinase activities.…”

“…The access to a rapid and inexpensive analytical method (in vitro) to estimate the ATTD of P in feed ingredients may improve diet formulation. In vitro enzymatic methods to evaluate the ATTD of P in feed ingredients and feeds have been suggested (Liu et al, 1998;Bollinger et al, 2004Bollinger et al, , 2005Roulin et al, 2008), unfortunately without direct in vivo validation. a One phytase activity unit (FTU) is the amount of enzyme that liberates 1 mol of inorganic P per minute from 5.1 mmol/l solution of sodium phytate, at pH 5.5 and 37 • C.…”