Lipid metabolism related gene-expression profiling in liver, skeletal muscle and adipose tissue in crossbred Duroc and Pietrain Pigs

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

“…The oral administration of ractopamine to pigs promoted lower fat accretion due to an attenuation of lipogenesis (Bergen 2001). Likewise, recent studies focusing on lipogenic gene expression have indicated that ractopamine reduces the expression of lipid synthesis genes, such as sterol regulatory element binding protein-1 (SREBP-1) and fatty acid synthase (FAS), in the adipose tissue of finishing pigs (Reiter et al 2007;Halsey et al 2011). Furthermore, the expression of peroxisome proliferator-activated receptor γ2 (PPARγ2), a transcription factor involved in adipogenesis, was decreased when pigs were fed ractopamine for 28 and 42 days (Halsey et al 2011).…”

“…Ractopamine may have a direct effect on porcine lipid metabolism due to both increased lipolysis (Fain and García-Sáinz 1983;Peterla and Scanes 1990) and reduced lipogenesis (Bergen 2001;Reiter et al 2007;Halsey et al 2011). However, reductions in fat deposition induced by ractopamine have not been clearly observed (Dunshea et al 1993(Dunshea et al , 1998Carr et al 2005b;Fernández-Dueñas et al 2008;Moore et al 2009;Boler et al 2010;Kutzler et al 2010).…”

Intermuscular and intramuscular adipose tissues: Bad vs. good adipose tissues

“…Few reports exist whereby this phenomenon even is evident in domesticated (meat) animals, but three studies are available evaluating this event in pigs. [133][134][135] In a study utilizing pigs of different body composition, Reiter et al demonstrated that genetic preference for leanness resulted in lower genetic markers for variables of adiposity and lipid metabolism within adipose tissue over pigs of more conventional body composition. 134 However, select skeletal muscle markers for oxidative metabolism of lipids were higher in the leaner pig group; suggesting that intramyocellular lipid is processed more rapidly in lean-type pigs over conventional pigs of similar age and such metabolism is heightened by application of commercially available b-adrenergic agents.…”

“…[133][134][135] In a study utilizing pigs of different body composition, Reiter et al demonstrated that genetic preference for leanness resulted in lower genetic markers for variables of adiposity and lipid metabolism within adipose tissue over pigs of more conventional body composition. 134 However, select skeletal muscle markers for oxidative metabolism of lipids were higher in the leaner pig group; suggesting that intramyocellular lipid is processed more rapidly in lean-type pigs over conventional pigs of similar age and such metabolism is heightened by application of commercially available b-adrenergic agents. 134 Utilizing genetically small pigs, which are isolated from other breeds, it was shown that diets to mimic dyslipidemic metabolic syndrome resulted in greater accumulation of intramyocellular lipid, but did not result in greater overall numbers of lipid droplets in pigs.…”

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

“…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). Furthermore, according to recent works focusing on lipogenic gene expression in the adipose tissue of finishing pigs, ractopamine can reduce the RNA transcription of genes related to lipid synthesis, such as sterol regulatory binding protein-1 (SREBP-1), which is a transcriptional factor that drive genes involved in the synthesis of fatty acids (Horton et al, 2003) and fatty acid synthase (Reiter et al, 2007;Halsey et al, 2011), a key enzyme involved in the synthesis of fatty acids (Ferreira et al, 2013). Although no difference was found in the weight gain between control and treatment groups during the experimental period (average of 170 g) ( Table 3), considering that ractopamine may have more efficacy on blocking lipogenesis instead of stimulating lipolysis (Mills et al, 2003), the animals that received ractopamine may have had a decrease of lipogenesis rate, especially at 8 mg kg −1 of ractopamine.…”