The determination of the choline content of feed ingredients using choline kinase

✍ Scribed by Menten, José Fernando M; Pesti, Gene M

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 184 KB
• Volume: 78
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/(sici)1097-0010(199811)78:3<395::aid-jsfa131>3.0.co;2-x

✦ Synopsis

This study was conducted to establish a methodology for a more accurate and less laborious determination of the choline content of feed ingredients, compared to the available procedures. The methodology involved an extractionhydrolysis step, in which the feed sample was heated in a methanolic KOH solution using a GoldÐsch apparatus, followed by an enzymatic assay, involving a series of coupled reactions started by choline kinase, which allowed the quantitation of the extracted choline. The enzymatic assay was very accurate over the range of choline concentrations from 1 to 20 mg l~1, with a lower detection limit in feeds of 50 mg kg~1. The hot extraction procedure was more efficient than the conventional thimble cool extraction for maize, soybean meal and canola meal, especially for maize. Extraction for 2 h gave choline values similar to those obtained with 4 or 6 h extraction. The recovery of added choline to maize, soybean meal or canola meal samples averaged 97É4%, indicating very little loss of choline in the procedure. This methodology provided more realistic values of the choline content of feed ingredients than previous methods.

1998 Society of ( Chemical Industry.