Silage Feature: Protein Breakdown in Silage Fermentation

The News Letter (Belfast, Northern Ireland), May 25, 2002 | Go to article overview

Silage Feature: Protein Breakdown in Silage Fermentation


A RECENT trial conducted at IGER investigated the effect of biological silage additives on the true protein content of silage.

Of the total nitrogen in fresh herbage approx. 75-90% is in the protein form. The remainder exists in the form of soluble nitrogen, which includes free amino acids. These free amino acids are not available for production and can range between 6 and 29% in the fresh crop.

Once plant material is ensiled there is a rapid breakdown of protein.

Studies have shown that ryegrass wilted over 3 days had 20% of its protein broken down to free amino acids and ammonia.

When a ryegrass/clover mixture was ensiled, a 60% drop in true protein was observed after 4 days of ensiling. This 60% decrease was due to the protein fraction that would have been available for production, being broken down into free amino acids and ammonia.

Amino acids are either essential or non-essential. An esential amino acid is a form of protein that must form part of the ruminant diet, as it cannot be synthesised in the rumen. A non-essential amino acid is a form of protein that is not required in the diet as it can be synthesised from other forms of protein.

Essential amino acids (examples):

Glutamine

Aspartine

Lysine

Methionine

Non-essential amino acids and derivatives (examples):

GABA (gamma amino butyric acid)

Ortnithine

Alanine

Naturally occurring activities contribute to further breakdown of amino acids. This break-down during a silage fermentation is not uniform. Increased concentrations of alanine (a non-essential amino acid) are frequently observed and this may be due to aspartic acid (an essential amino acid) breaking down.

Protein breakdown during ensilage consistently results in decreased concentrations of other essential amino acids, such as glutamitic acid. In addition, increased levels of the non-essential amino acids, GABA and ornithine, have been noted. Ornithine is produced when arginine is broken down, whilst glutamitic acid is broken down to GABA.

Reducing protein breakdown

It has been proposed that dropping the pH to 4.3 during ensilage prevents further protein breakdown. However, applying an acid at strengths, which reduces the silage pH to 3.5 immediately after treatment, failed to prevent extensive protein breakdown within the first 4 days of ensiling.

In the same study, the highest level of true protein content was observed with a mixed species silage inoculant treatment, where a faster initial rate of pH decline was proposed to have suppressed protein breakdown.

Concentrations of free amino acids were similar between all silage additive treatments after 14 days despite a more rapid pH decline in innoculated silage. …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Silage Feature: Protein Breakdown in Silage Fermentation
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.