Ractopamine as a metabolic modifier feed additive for finishing pigs: a review

Abstract

The β-adrenergic agonist ractopamine is increasingly used in the swine industry due to higher consumer demand for leaner pork products. Redirecting nutrients to favor leanness rather than fat deposition, ractopamine improves growth and carcass traits of finishing pigs. However, the impact of this agonist on pork quality is not clearly defined. Understanding the biological effects of dietary ractopamine dose, treatment period, lysine levels, and the lysine to metabolizable energy ratio will help pork producers achieve improvements in animal performance, carcass leanness, and economic efficiency in swine production systems.

Effect of ractopamine on Nile tilapia in the end of grow-out period

“…In addition, stimulation of β-adrenergic receptor also inhibits the fatty acids and triacyglicerol synthesis (Mersmann, 1998). However, lipolysis may not be the preferred pathway to decrease fat deposition in other species fed ractopamine included in the diet, as in pigs (Almeida et al, 2012). In pigs, another action of ractopamine on fat metabolism is the promotion of lower fat accretion by reducing lipogenesis (Bergen, 2001), which could be explained by the reduction of the sensitivity on adipose tissue to insulin, as it happens in pigs under βAA stimulation, and an evidence of lipogenesis inhibition (Mills et al, 2002).…”

“…One aspect to consider regarding the utilization of ractopamine is that the response is not constant over time (Almeida et al, 2012), reaching higher improvement in the beginning of supplementation and decreasing along time (Andretta et al, 2011). According to Beermann and Dunshea (2005), β-agonists are active and effective when added during short periods of time (28-42 days), close to the end of the growing period in swine.…”

“…According to Beermann and Dunshea (2005), β-agonists are active and effective when added during short periods of time (28-42 days), close to the end of the growing period in swine. This can occur when ractopamine is provided at a constant level over long periods, as a result of down-regulation or desensitization of βAR, or both (Moody et al, 2010;Almeida et al, 2012). This work adopted a 31-day experimental period based on swine experiments Amaral et al, 2009), although the effect of desensitization can occur earlier in pigs than in fish Ferreira et al, 2013).…”

“…It is an exogenous substance often called repartitioning agent for its ability to redirect nutrients from adipose tissue and increase skeletal muscle deposition (Moody et al, 2000;Almeida et al, 2012). The nutrient redirection leads to an increased efficiency of energy use, resulting in improved growth and feed efficiency .…”

“…Currently, ractopamine has obtained regulatory approval as an additive in pig production in more than 20 countries, such as the United States, Canada, and Brazil (Almeida et al, 2012). However, its use in aquaculture has not been approved in any country yet.…”