PS5-12. Effects of Phytogenic and Postbiotic Feed Additives on Nursery Pig Performance

Abstract An experiment was conducted to evaluate 3 individual feed additives on nursery pig growth performance and livability compared to a negative control (NC). The test products included a phytogenic blend (PH), a postbiotic product (PB), and a product containing a combination of phytogenic and postbiotic components that differed from the PH and PB treatments (PP). In total, 2,304 weaned pigs (5.4 ± 0.08 kg initial body weight; BW) were allotted to 18 replicate pens per treatment (32 pigs per pen) in 2 barns. Pens were blocked by location within barn and randomly allotted to treatment. Dietary treatments were fed in the first two nursery phases (phase 1: day 0 to 9; phase 2: day 9 to 22) followed by a common diet fed until the end of study (day 42). The phytogenic was included in the diet at 0.04%, the other test products were included in diets at 0.1%, and all diets included carbadox, pharmacological levels of zinc, and several other health-supporting feed technologies. Pen weights were recorded at the beginning and end of each phase. Data were analyzed using the lme4 package of R 4.1.2, and the statistical model included the fixed effect of treatment and the random effects of block and barn. Mortality was analyzed as a generalized linear mixed model with binomial distribution and reported as a probability. Growth performance in phase 1 did not differ by treatment, and likewise, no differences were observed for phase 2 final BW, average daily gain, or average daily feed intake. Phase 2 gain:feed tended to differ by treatment, with the greatest gain:feed observed for the postbiotic treatment (PB). Phase 3 growth performance did not differ by treatment, nor did overall growth performance. Phase 1 and 2 mortality tended to differ (P 0.10) between treatments. The NC treatment group had 4.15% mortality overall, whereas the treatments containing postbiotics resulted in 2.38% (PB) and 2.86% (PP) mortality (P = 0.106). In conclusion, most growth performance parameters were not influenced by dietary treatment; however, the treatments containing postbiotics tended to reduce mortality in the first 3 weeks post-weaning (P = 0.075). Overall, the postbiotic (PB) and PP group resulted in similar overall growth performance and numerically lower mortality compared to the negative control.