effects of abomasal infusion of phenylalanine on dry matter intake

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EFFECTS OF ABOMASAL INFUSION OF PHENYLALANINE ON DRY MATTER INTAKE, INTESTINAL FLOW AND NUTRIENT
DIGESTION IN STEERS
Enrique Alvarez-Almora1, Juan Manuel Pinos-Rodriguez2, Adelfo Vite-Aranda3, Juan Rodriguez-Garcia3, Martin Francisco
Montano-Gomez4, Richard Zinn5
1
Produccion Animal, Universidad Autonoma de Baja California, Mexicali, 2Instituto de Investigaciones Deserticas, Universidad
Autonoma de San Luis Potosi, San Luis Potosi, 3Instituto de Ciencias Agricolas, 4Instituto de Ciencias Veterinarias, Universidad
Autonoma de Baja California, Mexicali, Mexico, 5Animal Science Department, University of California-Davis, El Centro, CA, USA
To evaluate the effect of abomasal infusion of phenylalanine (Phe; 0, 5, 10 or 15 g/d) on DM intake (DMI), ruminal rate of flow and
digestibility, four Holstein steers with cannulas in the rumen, abomasum, and proximal duodenum, were used in a 4 x 4 Latin square
design. Steers had free access to a steam-flaked wheat-based diet. Chromic oxide was added to the diet as internal marker. There
were no differences in DMI, OMI, ruminal fermentation parameters, or intestinal flow of OM, NDF or N compounds. However, Phe
increased (Quadratic P < 0.10, Cubic P< 0.05) NDF digestion in the rumen, and increased the CP digested in the rumen (Linear P<
0.05). These changes in rumen digestibility may be due to changes in rumen motility; however, rumen motility was not measured in
the current experiment. In conclusion abomasal infusion of Phe does not change DMI or intestinal rate of passage, but it increases
rumen NDF and CP digestibility.
Keywords: Abomasal infusion, digestion, duodenal flow, intake, phenylalanine