Relação da ractopamina com componentes nutricionais e desempenho em suínos: um estudo meta-analítico

Abstract

Uma meta-análise foi realizada para avaliar a associação da ractopamina com variáveis nutricionais e de desempenho em suínos. A base de dados contemplou 29 artigos publicados em periódicos nacionais e internacionais entre 1990 e 2007, totalizando 155 tratamentos e 3.786 suínos em terminação. A inclusão média de ractopamina foi de 15,3ppm (variação de 0 a 30ppm) e a ingestão média diária de ractopamina foi 24,9mg (variação de 0 a 84mg). A inclusão de ractopamina nas dietas apresentou (P<0,05) correlação positiva com o ganho de peso (0,214) e com a eficiência alimentar dos animais (0,231). A ractopamina não alterou (P>0,05) o consumo de ração, mas aumentou (P<0,05) em cerca de 12% a eficiência alimentar, em 10% o ganho de peso e em 3,7% o peso vivo final dos animais. As concentrações de proteína, lisina e energia nas dietas afetaram a resposta dos animais suplementados com ractopamina. Para cada incremento em uma unidade percentual no conteúdo dietético de lisina, pode ser esperado aumento de 341g no ganho de peso (GMD=0,687+0,341LIS; R²=0,71) e de 1,3% na eficiência alimentar dos animais (EF=2,14+1,34LIS; R²=0,62). A ractopamina melhora o desempenho dos suínos, porém a interação do aditivo com os componentes nutricionais deve ser considerada para a formulação das dietas.

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

“…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.…”

Ractopamine for Pigs: A Review about Nutritional Requirements

“…Ractopamine is a ß-adrenergic agonist of phenethylamine group, with structure similar to the catecholamines, epinephrine and norepinephrine, and is an exogenous substance that alters the animal metabolism and distribution of nutrients favoring muscle deposition in relation to fat deposition [5,12]. Most mammals have adipose tissue with -receptors, which when activated by catecholamines promote lipolysis and thus reduce body fat.…”

“…The main action mechanism of ractopamine has been on adipose cells with reduced synthesis and deposit of subcutaneous fat by partial inhibition of lipogenesis, which allows for increased protein synthesis and improved quantitative characteristics of pig carcasses [19][20][21]. However, it has been found that these effects of ractopamine are partial and temporary on blocking of lipogenesis and become evident in heavier animals, where deposit of lipids in the carcass increases at a faster rate when compared to protein [5].…”

“…Utilization of ractopamine may be more efficient with increased intake of essential amino acids, since there is no use in having ß-adrenergic agonist if there is no retention of lysine and other essential amino acids to enable greater nitrogen retention in the muscles [5,6]. Increased levels of lysine in the diet has changed the productive responses in pigs fed diets with ractopamina ( Table 1), especially early in the administration of the -adrenergic agonist when the responses are more evident [5,7,8].…”

“…The protein deposit rate is directly related to increased demand for lysine, therefore ractopamine may alter the needs of this amino acid and other essential amino acids in pigs since there is a direct relationship between lysine and other amino acids for maximum protein deposit in the body of the animal [5,6]. Supplementing the diet with higher levels of lysine may alter production responses of pigs subjected to diets with ractopamine, especially early in the administration of -adrenergic (up to 14 days) when the responses are more evident [6][7][8].…”