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Effects of Skycis® and Stafac® on growth and carcass performance of finishing pigs – A meta analysis
The purpose of this meta analysis was to summarize the effects of 0 vs 15 ppm of narasin (NAR; Skycis®, Elanco Animal Health, Greenfield, IN; 4 studies located in Arkansas (AR), Ontario, CA (ON), Missouri (MO), and Minnesota) and the effects of 0 or 15 ppm NAR or 11 ppm of virginiamycin (VIR; Stafac®, Phibro Animal Health, Teaneck, NJ; 2 studies located in AR and ON) on the growth and harvest performance of pigs during the grow-finish period. Pigs were blocked by gender and weight and then treatments were randomly assigned to pens. Diet treatments consisted of a sequence of three to six diets containing corn, SBM, and DDGS (except ON and MO) with the appropriate amount of antimicrobial premix added. Pigs were weighed to determine initial BW, phase weights, and ADG. Feed issuance and weigh backs were recorded in order to determine ADFI and G:F. When pigs reached harvest BW, they were transported to food companies to measure HCW, fat depth, and loin depth. From 33.1 to 68.0 kg, pigs fed diets containing NAR had a faster ADG (0.981 vs 0.962 kg/d; P=0.0012) and a higher G:F (0.457 vs 0.452; P=0.0098) versus CON. From 68 kg to harvest, pigs fed diets containing NAR had a higher G:F (0.346 vs 0.337; P=0.0033) than those fed CON diets. Overall, pigs fed diets containing NAR had a faster ADG (0.985 vs 0.970 kg/d; P=0.0131) and an increased G:F (0.397 vs 0.390; P=0.0011) versus CON. Pigs fed diets containing NAR had a higher carcass weight (98.49 vs 97.44 kg; P=0.0069) than pigs fed CON. In the two-study analysis, pigs fed NAR from 27.3 to 68.0 kg (0.472 vs 0.466 or 0.467; P<0.05) and 68 kg to harvest (0.343 vs 0.335 or 0.336; P<0.05) had a higher G:F than those fed CON or VIR, respectively. From 27.3 kg to harvest, pigs fed diets containing NAR had a higher G:F (0.402 vs 0.394 or 0.395; P<0.05) than CON or VIR . Overall, pigs fed NAR had a higher ADG, G:F, and HCW than those fed CON and a higher G:F than those fed VIR.
Keywords: narasin, virginiamycin, pigs