Results of an international phosphorus digestibility ring test with broiler chickens

The objective of this ring test was to investigate the prececal phosphorus (P) digestibility of soybean meal (SBM) in broiler chickens using the trial protocol proposed by the World's Poultry Science Association. It was hypothesized that prececal P digestibility of SBM determined in the collaborating stations is similar. Three diets with different inclusion levels of SBM were mixed in a feed mill specialized in experimental diets and transported to 17 collaborating stations. Broiler chicks were raised on commercial starter diets according to station-specific management routine. Then they were fed the experimental diets for a minimum of 5 d before content of the posterior half of the ileum was collected. A minimum of 6 experimental replicates per diet was used in each station. All diets and digesta samples were analyzed in the same laboratory. Diet, station, and their interaction significantly affected (P < 0.05) the prececal digestibility values of P and calcium of the diets. The prececal P digestibility of SBM was determined by linear regression and varied among stations from 19 to 51%, with significant differences among stations. In a subset of 4 stations, the prececal disappearance of myo-inositol 1,2,3,4,5,6-hexakis (dihydrogen phosphate)-P; InsP6-P) also was studied. The prececal InsP6-P disappearance correlated well with the prececal P digestibility. We hypothesized that factors influencing InsP6 hydrolysis were main contributors to the variation in prececal P digestibility among stations. These factors were probably related to the feeding and housing conditions (floor pens or cages) of the birds in the pre-experimental phase. Therefore, we suggest that the World's Poultry Science Association protocol for the determination of digestible P be should extended to the standardization of the pre-experimental period. We also suggest that comparisons of P digestibility measurements among studies are made only with great caution until the protocol is more refined

Separation of ethoxylated bisphenol A dimethacrilates in dental composite after derivatisation to ionisable amines by capillary zone electrophoresis

Bisphenol A ethoxylate dimethacrylates (Bis-EMA) are transformed into ionisable amines by derivatisation in order to make the analytes applicable to capillary electrophoresis. For this goal, piperidine was added onto the C=C double bond of the alpha,beta-unsaturated ester group forming a tertiary amine with pKa values between 9 and 10. Formation of the derivatives was confirmed by electrospray ionisation MS. Commercial Bis-EMA is a mixture of homologues with different number of ethoxy groups; it is characterised by the average number of the ethoxy groups in the chains. These homologues were resolved by capillary zone electrophoresis at pH 4. It is shown for the product with an average of four ethoxy groups per Bis-EMA molecule that about seven homologues can be baseline separated when differing by only one ethoxy group. For Bis-EMA with 30 ethoxy groups in average, about 23 homologues could be differentiated. The high resolution power of capillary zone electrophoresis enables characterisation of commercial dental composite material concerning the Bis-EMA constituents