Effects of Saccharomyces Cerevisiae Postbiotics on the Performance of Growing-finishing Pigs Fed Diets with and Without Narasin

The objective of this study was to determine the effects of feeding 500 ppm of Saccharomyces cerevisiae postbiotics (CTX; celluTEIN X; Puretein Bioscience LLC, Minneapolis, MN, USA) fed to growing and finishing pigs provided diets with or without 15 ppm of narasin (NAR; Skycis 100 premix; Elanco Animal Health, Indianapolis, IN, USA). Crossbred pigs (2232 barrows and gilts housed in 72 pens across 2 barns with 29 to 31 pigs per pen) from a previous nursery experiment were fed a common diet for 10 days. Pens of pigs were weighed (average pig weight 35.7 kg) and allotted by weight to blocks of 4 adjacent pens. Four diet treatments were assigned to pens within block to create a randomized complete block design. Across replicates, previous nursery treatments were accounted for and balanced. Pigs were fed five phases of corn-soybean meal diets. Diet treatments were created by supplying 0 or 500 ppm of CTX or 0 or 15 ppm of NAR in 2 x 2 factorial arrangement. Pen body and feed weights were collected on Study Day 0 (allocation), 14, 28, 42, 56, 79 (first harvest), 93 (2nd harvest), and 101 (3rd harvest). Carcass data was not collected. Pen was the experimental unit. Statistical significance was determined at P ≤ 0.05 and tendencies declared between 0.05 < P ≤ 0.10. Bodyweights of pigs were not different (P > 0.10) among diet treatments for any of the time periods. During d 0 to 14, pigs fed NAR had greater ADG (P = 0.04) and ADFI (P = 0.04) than those of pigs not fed NAR. Also, pigs showed NAR x CTX effects for G:F (P = 0.01). During d 42 to 56, pigs tended to have NAR x CTX effects on ADFI (P = 0.07). During d 56 to 79, pigs fed CTX had greater (P = 0.05) G:F than those not fed CTX. Overall, pigs fed NAR tended to have greater (P = 0.08) ADG than those not fed NAR. Over the entire trial, pigs showed NAR x CTX ADFI (P = 0.10; tendency) and G:F (P = 0.03) effects. In conclusion, pigs fed 15 ppm of narasin tended to have greater daily gains. A synergy was observed when celluTEIN X was fed in combination with narasin and this resulted in the greatest G:F improvements. These data suggest that the combination of celluTEIN X and narasin can be a valuable tool to improve feed efficiency of growing and finishing pigs.