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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Research Project #442600

Research Project: Physiological, Microbiological, and Nutritional Mechanisms to Maintain Animal Productivity in the Absence of Antibiotics

Location: Agroecosystems Management Research

Project Number: 5030-31000-007-000-D
Project Type: In-House Appropriated

Start Date: Jul 22, 2022
End Date: Jul 21, 2027

To develop an understanding of intestinal integrity in nursery pigs, understand mechanisms involved in bacterial gene transfer using in vitro and ex vivo methodology, define mechanisms by which phenolic and pigment feed additives affects growth and physiological factors in nursery pigs, and determine the effects of lipid composition and quality affects the caloric value of such products in growing pigs; all in an effort to maximize production efficiency but minimize environmental impact. Specific objectives are: Objective 1: Develop in vitro and ex vivo models for assessing intestinal integrity. Objective 2: Evaluate the mechanism of bacterial gene transfer, and identify modulators, for a metal tolerance element containing genes for tolerance to copper, silver, and arsenic. Objective 3: Define mechanisms by which phenolics and pigments modulate animal growth, intestinal function, immune competence, microbial ecology, and bacterial gene transfer in swine. Objective 4: Determine how lipid composition and quality affects energy digestibility and growth performance parameters in growing pigs; and subsequently develop equations to predict digestible energy values for lipids in growing pigs.

Models for assessing intestinal integrity will be accomplished by three separate methods: through the feeding of different levels of dietary crude protein, by implementing different levels of feed restriction, and by inducing heat stress and hypoxia to nursery pigs, all of which have been suggested to affect gastrointestinal function. Mechanisms of bacterial gene transfer and identification of modulators associated with copper, silver, and arsenic will be accomplished by conjugation experiments using both in vitro and ex vivo methods, with a conjugation reporter system used to monitor horizontal transfer of integrative and conjugative gene elements from a donor to a recipient. Mechanisms by which phenolics and pigments modulate animal growth, intestinal function, immune competence, microbial ecology, and bacterial gene transfer will be accomplished by feeding nursery pigs diets containing either phenolics or pigments for a period of 42 days after which key criterion associated with each of these indices will be evaluated. To determine how lipid composition affect energy digestibility, saturated fatty acids with carbon chain lengths from 8 to 18 and the blending saturated fatty acids with an unsaturated fatty acid will be fed to nursery pigs for 28 days, during which fecal samples will be taken to assess total tract energy digestibility. Modeling will then be used to develop equations to predict digestibility energy values for each lipid as affected by saturated carbon length and concentration.