Date of Graduation

5-2020

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Poultry Science (PhD)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Coon, Craig N.

Committee Member

Caldas, Justina

Second Committee Member

Halley, John T.

Third Committee Member

Owens, Casey M.

Fourth Committee Member

Mauromoustakos, Andronikos T.

Keywords

Broiler; Corn; Enzyme; Net Energy; Soybean Meal

Abstract

The modern broiler is growing at a rapid rate generating tremendous amounts of heat. A sensitive Net Energy (NE) system is needed to measure body heat production (HP) generated primarily by daily maintenance and synthesis and degradation of myofibrillar and sarcoplasmic protein. The first two chapters present evaluation of the classic way to calculate NE versus a new methodology; the Arkansas NE (Ark NE) system, with birds from two genetic lines fed diets with different AA content or different ME content in two different environmental temperatures.

Utilizing together the Net Energy maintenance (NEm), determined from indirect calorimetry, and Net Energy gain (NEg), evaluated through DEXA, provide valuable information about type of gain and current broiler genetics. This combination provides a deeper understanding of diet NE, rather than the small indigestible fraction differences which have been only measured through heat increment (HI). Taking advantage of understanding the genetics and appropriate environment is an advantage of NE formulation. In addition, protein, the source and type of fat (fat vs. starch vs. protein) makes a difference in how energy is metabolized by broilers. Research in feeding broilers exogenous composite enzyme, either alone or in combination with exogenous amylase, showed protein is primarily going to go into retained energy while energy coming from carbohydrate is going to be in a functional form, i.e. fuel for metabolic processes. Therefore, providing energy in the appropriate amount but also in the correct metabolic form will manipulate the amount of protein or fat deposited and ultimately the retained energy (NEg). Net energy calculations proved to be a sensitive way to evaluate enzyme addition to broiler diets.

Lastly, utilizing digestible amino acids and other nutrient contents of the ingredients, even undesirable qualities, can be used to understand net energy calculations.

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