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Tipo:	Tese
Título:	Rumen-protected lysine for dairy cows: stability, bioavailability and lactation performance
Autor(es):	Victor Marco Rocha Malacco
primer Tutor:	Ronaldo Braga Reis
primer Co-tutor:	Shawn S. Donkin
Resumen:	The guiding hypothesis explored in this dissertation is that the value of rumen-protected lysine (RP-Lys) is a function of its stability when premixed in feeds, inertness in the rumen, post ruminal bioavailability, and impact on production parameters when fed to lactating dairy cows. A second hypothesis tested was that lysine and energy supply act to regulate genes that are critical for lysine catabolism in bovine. To test these hypotheses, four related studies were performed. The studies evaluated the rumen-protected Lys product stability, bioavailability and lactating dairy cow’s performance due to its use as a supplement in Lys deficient corn-based diets and determined the effects of extracellular Lys levels and energy supply on aminoadipate-semialdehyde synthase (AASS) mRNA expression as an indicator of a gene specific to Lys catabolism. Overall, summarizing all those studies related to the RP-Lys we conclude that association of the storage practices before feeding RP-Lys and the low bioavailability observed in the bioavailability trial might result in a lower delivery than predicted for digestible Lys in the small intestine resulting in a lack of response in the lactation trial. In addition, multiple AA may have been limiting when most of the dietary protein was derived from corn products which could also dampen the expected increase in plasma Lys and increase of milk yield and milk components. The increase in the Lys in the media and providing an additional energy source did not translate in alterations in the AASS expression and confirms data from in vivo studies with increased postruminal lysine supply. Taken together, the information presented in this thesis highlights the importance of maintaining the integrity of the protection technology for RP-Lys through all sequential segments leading to postruminal presence of free lysine.
Asunto:	Zootecnia
Idioma:	eng
País:	Brasil
Editor:	Universidade Federal de Minas Gerais
Sigla da Institución:	UFMG
Departamento:	VET - DEPARTAMENTO DE ZOOTECNIA
Curso:	Programa de Pós-Graduação em Zootecnia
Tipo de acceso:	Acesso Restrito
URI:	http://hdl.handle.net/1843/32623
Fecha del documento:	13-dic-2019
Término del Embargo:	13-dic-2020
Aparece en las colecciones:	Teses de Doutorado

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