J. Anim Sci.
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J. Anim Sci. 1976. 42:524-528.
© 1976 American Society of Animal Science
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In Vitro Evaluation of Protected Feeds for Ruminants from Alfalfa Protein and Safflower Oil

C. K. Lyon1, D. A. Dinius2 and G. O. Kohler1

U.S. Department of Agriculture, Berkeley, California 94710 and Beltsville, Maryland 20705

Abstract

Protected feed supplements were prepared on a laboratory scale by emulsifying safflower oil with freshly pressed alfalfa juice and then coagulating the alfalfa protein either by heating to 80 C or by adjusting the pH to 3.5 at room temperature. In every case the oil came down almost quantitatively with the protein. The coagulated material was mixed with calculated amounts of 40% formaldehyde, held for 1 day and then dried at 50 C.

Digestibility of protein in the samples was evaluated, in vitro, by incubation in ruminal fluid, followed by treatment with pepsin. Protection of linoleic acid from microbial hydro-genation was determined by gas-liquid chromatographic analysis of oil extracted from samples after the incubation in ruminal fluid. When the formaldehyde treatment was increased from 0 to 16% (based on protein), digestibility of protein in ruminal fluid decreased from about 50 to 1% and protection of linoleic acid increased from about 40 to 95%. Total digestibility of protein in ruminal fluid, then pepsin, was about 80% without formaldehyde treatment and remained at about 60% with addition of 1 to 16% formaldehyde.

Added emulsifiers caused a small improvement in the protection of linoleic acid in acid-precipitated samples but had no significant effect on the degree of protection of heat-precipitated samples.

Footnotes

1 Western Regional Research Laboratory, Agricultural Research Service, Berkeley, California.

2 Ruminant Nutrition Laboratory, Nutrition Institute, Agricultural Research Service, Beltsville, Maryland.






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Copyright © 1976 by the American Society of Animal Science.