Using Pulse Dose Abomasal Infusion To Determine Bioavailability Of Rumen Protected Amino Acid Products
Date
2022-05
Authors
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Journal ISSN
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Publisher
University of Delaware
Abstract
Dairy cattle diets are often deficient in limiting amino acids which can have a
negative effect on production. Dietary supplementation of limiting amino acids to
dairy cattle offers the potential to meet amino acid requirements without increasing
protein feeding, thereby reducing environmental nitrogen losses, while maintaining or
increasing milk production.
Dairy cattle are classified as ruminants and have microorganisms that reside in
their rumen. Protective coatings need to be placed onto supplemented amino acid
products to ensure that the rumen microbes do not destroy the nutrients. A certain
balance must be achieved with the rumen protection coating so that there is sufficient
rumen protection, but the product is available for absorption in the intestine. There are
limitations to the rumen protected amino acids currently on the market, and
development of new products that are more available to the cows will benefit dairy
producers. Plasma amino acids respond linearly to increased amino acid absorption, so
by analyzing blood samples we are able to measure bioavailability of newly developed
products.
Our research was a preliminary study that examined 3 methionine and 4 lysine
product prototypes. Our objective was to identify potential candidate prototype
products for further studies based off the results. This experiment used 3 late lactation
(167 ± 86 days in milk) multiparous Holstein cows with preexisting ruminal cannulas. Products were first incubated in the rumen, and then abomasally infused using a pulse
dose technique. Blood was sampled 14 times per period per cow at various time points
for plasma free amino acid analysis. The area under the curve (AUC) for the rumen
protected amino acid (RP-AA) products was compared to the AUC for the respective
unprotected amino acid, which resulted in a calculated bioavailability for each rumen
protected product.
The results showed that the lysine products fell into the bioavailable range of
20-32% when calculated based on the starting product, and 28-52% for the infused
product. On the other hand, methionine had an average bioavailability of 72-157%
when looking at the starting product, and 137-197% for the infused product. Lysine
had believable results, while methionine is inflated due to the differences of the
plasma response to the raw amino acid compared to the product.
The importance of this research was to determine the bioavailability of specific
free amino acid supplements and apply that knowledge into creating a product that is
marketable. It is important to have an amino acid dietary supplement that is affordable
to consumers, and helps dairy cows increase their production level while decreasing
their environmental footprint.
Description
Keywords
Amino acid, Dairy cattle, Rumen