Colorimetric determination of in vitro feed protein degradation

Abstract

A colorimetric method for determining protein degradation us' ing a diazonium chromophore was compared with the dacron bag technique.D iazotizedf ish meal, maizeg luten meal and soya-bean were incubated with strained rumen fluid and a suitableg rowth medium. Only 49o/oa nd 18% of the colour bound to soya-bean was bound to fish meal and corn gluten meal, respectivelyD. egradationv aluese xpresseda s a percentage of the total amount actually bound to the dye were in reasonablea greementw ith dacron bag estimates.H owever,i ni' tial hydrolysis of the diazo feeds was very rapid with little increment in breakdown after two hours incubation. lt was con' cluded that this problem was probably largely a result of limited penetration of the chromophore to potentially reactive sites within the feed particles owing to the large molecular size of the diazonium chromophore.

'n Kolorimetriesem etodev ir die bepalingv an proteTenafbraak met 'n diazonium kromofoor is met die dakronsak tegniek vergelyk. Diazo vismeel, mielie glutenmeel en sojaboon is met rumenvloeistofe n groeimediumg einkubeer.S legs 49ohe n 18oh van die kleur gebind aan sojaboon is aan vismeel en mielie glutenmeelo nderskeidelikg ebind.P rotelenafbraawk aardes, uitgedruka s 'n persentasiev an die totale hoeveelheidg ebind deur die kleurstofw as in redelikeo oreenstemmingm et dakron' sak waardes.A anvanklikeh idrolisev an die diazo-voerew as baie vinnig,m et slegs klein veranderingsin afbraakn a twee ure. Daar is tot die gevolgtrekkingg ekom dat hierdiep robleem waarskynlik toe te skryf is aan die beperkte indringing van die kromofoor na potensieel reaktiewe punte binne die voer partikels weens die groot molekulOreg roottev an die diazonium kromofoor.

Keywords: Nitrogen,protein,degradability diazotization in vitro, dacron bag