Splanchnic nitrogen metabolism by growing beef steers fed sorghum grain flaked at various densities

Persistent Link:
http://hdl.handle.net/10150/289222
Title:
Splanchnic nitrogen metabolism by growing beef steers fed sorghum grain flaked at various densities
Author:
Alio, Abdoulaye, 1953-
Issue Date:
1997
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Growing beef steers were used in completely randomized block designs to evaluate effect of processing method, dry-rolled (DR) versus steam-flaked (SF) sorghum, and degree of processing (flaking density) of corn and sorghum grain on nitrogen (N) digestion and post-absorptive N metabolism. In experiments (Exp.) 1 and 2, seven duodenally and ileally cannulated steers were used to investigate N digestibilities. Experimental diets contained 77% grain: Exp. 1, DR or SF sorghum at densities of 437, 360 and 283 g/L (SF34, SF28, SF22); Exp. 2, corn at two flake densities (SF34 and SF22). Nitrogen intakes by steers fed sorghum (142 g/d) and corn (149 g/d) diets were similar among treatments. Steers fed SF compared to DR, increased ruminal (P =.04) DM digestibility. Microbial protein flow to the duodenum averaged 10% greater for SF vs DR. Reducing flaking density of sorghum grain linearly increased (P .05) ruminal DM and tended to increase linearly ruminal feed N (P =.11), total tract DM and N digestibilities and microbial efficiency (P .08). Unexpectedly, flake density did not affect DM or N digestibilities of SF corn diets by steers. In Exp. 3, eight steers implanted with indwelling catheters were used to measure blood flow, net absorption and uptake of ammonia-N, urea-N (UN) and alpha-amino N (AAN) across portal-drained viscera (PDV), hepatic and total splanchnic tissues. Experimental diets were the same as those in Exp. 1. Six arterial, portal and hepatic blood samples were collected per day at 2 h intervals for each diet and steer. Daily DM and N intakes averaged 7.0 kg and 142 g, respectively. Decreasing flake density of SF sorghum linearly increased net absorption of AAN (P =.04) and UN recycling to the gut (P =.02). Net UN recycling to the gut averaged 38% of N intake across treatments. Steers fed SF compared to DR decreased (P =.03) net splanchnic UN output (33 vs 50 g/d). The improved N retention and lower splanchnic UN output, contingent with greater ruminal microbial protein synthesis and flow to intestines may explain in part the observed higher performance of cattle fed SF compared to DR sorghum. Based on improved total tract N digestibilities and greater net absorption of AAN and UN recycling to the gut, optimum flake density for SF sorghum grain was 283 g/L (SF22).
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Biology, Animal Physiology.; Agriculture, Animal Culture and Nutrition.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Animal Sciences
Degree Grantor:
University of Arizona
Advisor:
Theurer, C. Brent

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleSplanchnic nitrogen metabolism by growing beef steers fed sorghum grain flaked at various densitiesen_US
dc.creatorAlio, Abdoulaye, 1953-en_US
dc.contributor.authorAlio, Abdoulaye, 1953-en_US
dc.date.issued1997en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractGrowing beef steers were used in completely randomized block designs to evaluate effect of processing method, dry-rolled (DR) versus steam-flaked (SF) sorghum, and degree of processing (flaking density) of corn and sorghum grain on nitrogen (N) digestion and post-absorptive N metabolism. In experiments (Exp.) 1 and 2, seven duodenally and ileally cannulated steers were used to investigate N digestibilities. Experimental diets contained 77% grain: Exp. 1, DR or SF sorghum at densities of 437, 360 and 283 g/L (SF34, SF28, SF22); Exp. 2, corn at two flake densities (SF34 and SF22). Nitrogen intakes by steers fed sorghum (142 g/d) and corn (149 g/d) diets were similar among treatments. Steers fed SF compared to DR, increased ruminal (P =.04) DM digestibility. Microbial protein flow to the duodenum averaged 10% greater for SF vs DR. Reducing flaking density of sorghum grain linearly increased (P .05) ruminal DM and tended to increase linearly ruminal feed N (P =.11), total tract DM and N digestibilities and microbial efficiency (P .08). Unexpectedly, flake density did not affect DM or N digestibilities of SF corn diets by steers. In Exp. 3, eight steers implanted with indwelling catheters were used to measure blood flow, net absorption and uptake of ammonia-N, urea-N (UN) and alpha-amino N (AAN) across portal-drained viscera (PDV), hepatic and total splanchnic tissues. Experimental diets were the same as those in Exp. 1. Six arterial, portal and hepatic blood samples were collected per day at 2 h intervals for each diet and steer. Daily DM and N intakes averaged 7.0 kg and 142 g, respectively. Decreasing flake density of SF sorghum linearly increased net absorption of AAN (P =.04) and UN recycling to the gut (P =.02). Net UN recycling to the gut averaged 38% of N intake across treatments. Steers fed SF compared to DR decreased (P =.03) net splanchnic UN output (33 vs 50 g/d). The improved N retention and lower splanchnic UN output, contingent with greater ruminal microbial protein synthesis and flow to intestines may explain in part the observed higher performance of cattle fed SF compared to DR sorghum. Based on improved total tract N digestibilities and greater net absorption of AAN and UN recycling to the gut, optimum flake density for SF sorghum grain was 283 g/L (SF22).en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectBiology, Animal Physiology.en_US
dc.subjectAgriculture, Animal Culture and Nutrition.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAnimal Sciencesen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorTheurer, C. Brenten_US
dc.identifier.proquest9729512en_US
dc.identifier.bibrecord.b34819241en_US
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