Die huidige stand van proteïenevaluasie

Abstract

The current status of protein evaluation. Six new protein evaluation systems from the USA and Europe are compared as regards the essential elements and efficiency coefficients used in each system. There are considerable differences in terms of microbial protein production per unit energy intake, digestibility of microbial crude protein and undegraded dietary protein, as well as efficiency of utilization of absorbed amino acids. The protein requirement and total dietary composition for a high-producing dairy cow, as calculated by each system, is given as an example. Protein degradability values for various South African feedstuffs are given and the practical application of the degradable protein system is discussed.

Ses nuwe proteïenevalueringstelsels vanuit die VSA en Europa word vergelyk in terme van die essensiële elemente en doeltreffendheidskoëffisiënte wat in elke stelsel gebruik word. Daar is aansienlike verskille ten opsigte van mikrobiese proteïenproduksie per eenheid energie-inname, verteerbaarheid van mikrobiese ruproteïen en niedegradeerbare proteïen, sowel as doeltreffendheid van benutting van geabsorbeerde aminosure. Die proteïenbehoeftes en totale dieetsamestelling van 'n hoogproduserende melkkoei, soos bereken volgens elk van die stelsels, word as voorbeeld gebruik. Proteïendegradeerbaarheidswaardes van verskeie Suid-Afrikaanse dieetkomponente word gegee en die praktiese toepassing van die degradeerbare proteïenstelsel word bespreek.

Keywords: Protein evaluation systems, rumen degradable protein, undegraded dietary protein.