International Journal of Advance Agricultural Research
ISSN: 2053-1265
Vol. 10(2), pp. 20-31, March 2022
doi.org/10.33500/ijaar.2022.10.003

Effect of ractopamine on digestible lysine requirement for finishing pigs under high ambient temperatures

Souza M. F.⃰, Souza T. V. M., Braga D. A. M., Faria L. F., Furtado J. M. S. and Donzele J. L.

Department of Animal Science, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Campus Universitário, Viçosa, Minas Gerais, Brazil, zip code: 36570-000.

*To whom correspondence should be addressed. E-mail: matheusfari@yahoo.com.br.

Received 01 February, 2022; Received in revised form 22 February, 2022; Accepted 25 February, 2022.

Abstract

Keywords:
Additive, Amino acid, Meat quality, Beta-adrenergic agonist.

The objective of this research was to study digestible lysine (Lys) levels in diets supplemented or not with ractopamine for finishing pigs in the summer period, where 128 commercial castrated male, hybrid pigs were selected for meat deposition, with an average weight of 81.2 ± 3.3 kg, distributed in an experimental design randomized blocks, in a 4 × 2 factorial arrangement - four digestible Lys levels (0.736; 0.836; 0.937 and 1.038%) and two levels of ractopamine (0 and 10 ppm) – with eight repetitions and two animals per experimental unit. Interaction was observed between the levels of Lys and ractopamine on pork backfat thickness. There was an effect of the levels of Lys with or without the addition of ractopamine on: feed conversion, daily consumption Lys, backfat thickness, loin eye area, loin depth, loss of liquid per cooking and the amount of lean pig meat. The concentrations of Lys when supplemented with ractopamine affected cooking loss of swine longissimus dorsi. Supplementation with ractopamine in the feed improved final weight, daily weight gain, feed conversion, backfat thickness, rib eye area, percentage of lean meat, loin depth and loss of liquid by cooking the animal longissimus dorsi muscle. It was concluded that rations with 10 ppm of ractopamine improve the performance of finishing pigs, and that the level of digestible Lys with 10 ppm of ractopamine in the finishing phase in summer is 1.038% corresponding to 29.3 g of consumption per day, while in rations without ractopamine is 0.945% corresponding to 28.4 g of consumption per day.