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Doctoral Thesis
DOI
https://doi.org/10.11606/T.10.2016.tde-23032016-102856
Document
Author
Full name
Nara Regina Brandão Cônsolo
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Pirassununga, 2015
Supervisor
Committee
Gobesso, Alexandre Augusto de Oliveira (President)
Andrighetto, Cristiana
Goulart, Rodrigo Silva
Rennó, Francisco Palma
Saran Netto, Arlindo
Title in Portuguese
Uso de agonista β-adrenérgico na dieta de bovinos de corte
Keywords in Portuguese
Eficiência alimentar
Nelore
Qualidade da carne
Ractopamina
Zilpaterol
Abstract in Portuguese
O objetivo desse estudo foi avaliar o efeito do Cloridrato de Zilpaterol (ZH), Ractopamina (RH) e aumento no nível de proteína da dieta, em dois experimentos distintos na dieta de animais Nelore em sistema de confinamento, nas características produtivas, metabólitos sanguíneos, características de carcaça, composição de corpo vazio e ganho, qualidade da carne e expressão gênica. Para isso, foram realizados dois experimentos. O Exp. 1 utilizou 48 machos, não castrados, distribuídos em blocos casualisados em 4 tratamentos em arranjo fatorial 2x2, sendo dois níveis de PB: 100 e 120% e dois níveis de RH: 0 e 300mg/animal/dia. No Exp. 2, foram utilizadas 72 novilhas da raça Nelore distribuídas em delineamento em blocos casualizados. As novilhas foram separadas em dois grupos: Controle (CONT) e Zilpaterol (ZH). Em ambos os experimentos, os animais foram pesados periodicamente e amostras de sangue foram coletadas. Após o abate, o PCQ foi avaliado, amostras da musculatura foram obtidas para análise de PCR. Depois do resfriamento das carcaças, a AOL e EGS foram avaliados, amostras do músculo Longissimus e a sessão entre a 9ª e 11ª costelas foram coletadas. Além disso, no Exp. 2, as novilhas foram abatidas de forma seriada, 0, 20 e 30 dias de suplementação com ZH e no último abate, foi realizada a desossa completa da meia carcaça. A suplementação com RH aumentou o GMD, diminuiu CMS na dieta com PB120, e aumentou a eficiência alimentar, o teor de proteína plasmática e a atividade da ALP na dieta PB120, diminuiu a glicose na dieta PB100. Além disso, a RH diminuiu a FC nas carnes sem maturação e a dieta com 120% de proteína aumentou a FC nas carnes 0 e 7 dias maturadas. No Exp. 2, as novilhas suplementadas com ZH tiveram aumento no GMD, PCQ, EA, creatinina plasmática e diminuição dos AGNE. A composição de corpo vazio foi alterada após 20 dias de suplementação com ZH. O ZH aumentou o ganho de PCV, ganho de proteína e rendimento da maioria dos cortes do traseiro especial. Houve um aumento na FC aos dias 7 e 14 de maturação. O painel sensorial detectou diminuição da maciez da carne de animais alimentados com ZH, independentemente do tempo de maturação, e diminuição a suculência da carne nos tempos 0 e 14 de maturação. O ZH aumentou a expressão das enzimas calpaínas e calpastatina. Os resultados do presente estudo mostram aumento no desempenho produtivo dos animais alimentados com RH e ZH. A suplementação com ZH aumentou o rendimento dos cortes e mudou a composição corporal de ganho. O uso de agonista β-adrenérgico melhora a eficiência do sistema e aumenta a deposição de tecido magro da carcaça, gerando maior rentabilidade por animal abatido
Title in English
The use of β-adrenergic agonist in beef cattle diet
Keywords in English
Feed efficiency
Meat quality
Nellore
Ractopamine
Zilpaterol
Abstract in English
The aim of this study was to evaluate the use of Zilpaterol and Ractopamine Hydrochloride, in two distinct experiments on Nellore diet in feedlot system, for growth performance, serum metabolites, carcass traits, empty body weight composition, carcass gain composition, meat quality and gene expression. The Exp. 1 used 48 bulls, randomly assigned to four treatments in a 2x2 factorial arrangement; two levels of dietary CP: 100% and 120% of metabolizable protein requirement, defined as CP100 and CP120, respectively. Moreover, two levels of RH: 0 and 300 mg/animal/per day. The Exp. 2 used 72 Nellore heifers assigned to a randomized block design. Heifers were separated into 2 groups: Control and Zilpaterol (ZH). In both experiments, the animals were weighed and blood samples were taken periodically. Animals were slaughtered and HCW was recorded, muscle samples were taken to PCR analysis. After chilling, LMA and fat thickness were recorded, longissimus samples and the 911th rib section were obtained. In addition, in the Exp. 2, heifers were sub groups were slaughterer at 0, 20 and 30 days of ZH supplementation, in the last slaughterer, the carcass were debone. Supplementation with RH increased ADG, reduced DMI at CP120, improved G:F, plasma total protein at CP120, also decreased plasma glucose concentration at CP100, and increased ALP activity at CP120. Ractopamine decreased meat shear force, at day 0 of aging. Greater dietary protein increased meat shear force after 0 and 7 days of aging. Heifers fed ZH had gains in ADG, HCW, G:F ratio, increased serum creatinine, and decreased serum NEFA. Zilpaterol increased carcass dressing percentages, and also decreased kidney-pelvic fat. The EBW composition was changed after 20 d of ZH supplementation. The ZH increased EBW gain, EB protein gain, and subprimal yield. There was an increase on WBSF after 7 and 14 d of aging. The sensory panelists reported a decreased on meat tenderness by ZH supplementation, regarding aging time, and a decrease on juciness at 0 and 14 d of aging. The ZH increased the calpain and calpastatin gene expression. These results indicate the efficiency of RAC and ZH to improve the performance,feed efficiency, and muscle mass deposition in Nellore bulls and heifers. Greater CP did not further improved the RAC effect. The ZH supplementation increased the subprimal yield and changed body gain composition. Finally, the use of β-adrenergic agonist increase the beef cattle system's efficiency by increasing the lean carcass component, with greater profitability per slaughtered animal
 
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Publishing Date
2016-04-15
 
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