Table 1.

Summary of the physiological effects of ractopamine administration in livestock animals.

Feed Additives	Animals	Concentration	Physiological Effects	References
Ractopamine	Crossbred gilts and barrows	0 and 20 ppm	Improved feed efficiency, average daily gain (ADG), and decreased cooking loss of loin	[27]
Ractopamine	Pigs	20 mg/kg	Increased ADG, decreased feed conversion ratio (FCR), higher carcass lean proportion	[28]
Ractopamine	Pigs	0, 5, 10, and 20 mg/kg	Increased growth (p < 0.001), better efficiency (p < 0.001), and intensified muscular profile (p < 0.001)	[29]
Ractopamine	Dogs	1 mg/kg	Acute myocardial activity	[30]
Ractopamine and clenbuterol	Roundworm (Caenorhabditis elegans)	10 µg/L	Decreased brood size, alteration in locomotion behavior, reduced lifespan	[31]
Ractopamine	Cattle	200 to 350 gm/animal	Increased protein deposition and decreased lipogenesis, increased feed efficiency, increased ADG, and increased carcass weight	[26]
Ractopamine	Cattle	200 mg/animal/day for 28 to 42 days	Increased incidence of death (from 0.59 to 1.129/10,000 cattle)	[32]
Ractopamine	Pigs	0 mg/kg to 7.4 mg/kg	Increased ADG (18.8%), improved gain-to-feed efficiency (23.7%), increased carcass yield (0.7% units), and reduced backfat depths (6.3%) as compared to control (0 mg/kg)	[33]
Ractopamine + CON basal diet	Pigs	CON basal diet, CON + 1% ractopamine	Increased lean meat in the RAC group, fecal score, and growth performance was nonsignificant	[34]