Altering Amino Acid Supply to the Small Intestine in Ruminants

Orias, Fernando

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Description

Title

Altering Amino Acid Supply to the Small Intestine in Ruminants

Author(s)

Orias, Fernando

Issue Date

2000

Doctoral Committee Chair(s)

Merchen, Neal R.

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Biology, Animal Physiology

Language

eng

Abstract

Experiments were conducted to modify the flow of amino acids (AA) to the small intestine (SI) in ruminants. In Experiment 1, five steers (450 kg) with cannulas in the rumen, proximal duodenum, and terminal ileum were used in a 5 x 5 Latin square design to evaluate the site and extent of digestion of nitrogenous compounds by steers fed raw soybeans or soybeans extruded at temperatures of 116, 138, and 160°C. No differences were observed between the raw and extruded soybeans (P = .81), or for the linear or quadratic effects of extrusion temperature (P = .56 and P = .45, respectively) for N (g/d) reaching the SI. Small intestinal N disappearance (% of N entering) increased linearly (P = .01) when extrusion temperatures increased from 116 to 160°C. Significant differences (P < .10) due to extrusion temperatures were detected for flows of individual, essential (EAA), non-essential (NEAA), and total AA at the duodenum. Essential AA, NEAA, and total AA disappearance from the SI was increased linearly (P < .10) with increasing extrusion temperature. Extrusion of soybeans can protect soy protein against extensive ruminal degradation, while not compromising intestinal digestibility. In Experiment 2, a rumen protected (RP) lysine and methionine product was evaluated to determine its ability to resist ruminal degradation and provide available methionine and lysine to the SI in a digestion study using steers with cannulas in the rumen, proximal duodenum, and terminal ileum. Lysine and methionine flows to the SI were not affected by addition of increasing amounts of RPAA to the diets. Feeding the supplemental RPAA did not increase the amount of lysine or methionine disappearing from the SI (P = .44 and P = .87, respectively). In Experiment 3, porcine meat and bone meal samples were evaluated as a protein supplement for ruminants. Values for escape essential AA (EEAA), escape methionine, escape lysine, and net intestinally available methionine and lysine (NIAMet, NIALys) were obtained by combining rates and extents of ruminal N disappearance with AA digestibilities of in situ residues measured in cecectomized roosters. Experiment 4 was designed to evaluate porcine meat and bone meal alone and in combination with soy bean meal (SBM), or corn gluten meal (CGM) for their ability to provide absorbable AA to the SI. No differences due to diet were detected for flows of EAA, NEAA, and total AA (g/d) reaching the SI (P = .24, P = .12, and P = .16, respectively), but SI disappearance (g/d) of EAA, NEAA, and total AA were greatest when steers were fed pMBM alone or in combination with CGM (P ≤ .10), than when the other experimental diets were fed. It has been proven that there are ways to effectively alter the AA supply to the SI in ruminants. However, more research is needed in order to be able to accurately determine the AA requirements for different stages and levels of production and couple it with reliable methods of predicting AA reaching the SI from bacterial and dietary origin to fully express the genetic potential for growth and milk production.

Graduation Semester

2000

Type of Resource

text

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