Effect of ractopamine on digestible-lysine requirement for finishing barrows under thermoneutral conditions

Autor:	D. A. M. Braga, Rita Flávia Miranda de Oliveira Donzele, F. C. O. Silva, L. F. Faria, Matheus Faria de Souza, Evandro Ferreira Cardoso, Juarez Lopes Donzele, T. V. Maurício
Rok vydání:	2019
Předmět:	Animal fat 040301 veterinary sciences Lysine Animal production 0402 animal and dairy science 04 agricultural and veterinary sciences Loin Body weight 040201 dairy & animal science Feed conversion ratio 0403 veterinary science Ractopamine chemistry.chemical_compound Animal science chemistry Animal Science and Zoology Food Science Lean meat
Zdroj:	Animal Production Science. 59:531
ISSN:	1836-0939
DOI:	10.1071/an17163
Popis:	The purpose of the present study was to determine the digestible-lysine (Lys) requirement in diets supplemented or not with ractopamine (RAC), so as to maximise performance and carcass characteristics for finishing barrows reared at thermoneutral conditions. In total, 128 high-lean commercial hybrid barrows with an initial bodyweight of 78.2 ± 4.3 kg were distributed in a completely randomised block design, in a 4 × 2 factorial arrangement (four Lys concentrations: 0.730%, 0.830%, 0.930% and 1.030% and two RAC inclusions: 0 and 10 mg/kg), with two animals per pen and eight pens per treatment. Lys concentrations tested significantly (P < 0.05) affected digestible-lysine intake, and the absolute (g) and relative (%) lean meat content, regardless of RAC inclusion. When diets were RAC-supplemented, feed conversion rate of animals was improved and, in addition, final bodyweight, daily bodyweight gain, loin eye area, loin eye depth, and absolute (g) and relative (%) carcass lean meat content increased (P < 0.05). RAC inclusion also decreased (P < 0.05) backfat thickness and the colour values a* and b* of finishing pigs. Therefore, on the basis of our results, it can be inferred that the best performance and carcass characteristics for finishing barrows reared at thermoneutral conditions were obtained at 1.030% and 0.730% Lys respectively, corresponding to an estimated daily Lys intake of 34.3 g and 24.2 g, independently of the diet RAC concentration.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::de07d45332047c9f9bc005a5be183739 https://doi.org/10.1071/an17163 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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