Effect of Natural Feed Additives As Alternatives to in-Feed Antibiotics on the Performance of Nursery Pigs

This study was designed to evaluate natural feed additives as alternatives to in-feed antibiotics on nursery pig performance. Natural feed additives used in the present study consist of 1) Biotronic^® Top3 (a blend of formic, propionic, and acetic acids combined with cinnamaldehyde and permeabilizing complex; BIOMIN Holding GmbH) and 2) Digestarom^® P.E.P. (a phytogenic blend of oregano, anise, and citrus oil, and fructo oligosaccharide; BIOMIN Holding GmbH). Weaned pigs (PIC 280 x 1050, n=480; BW=6.22 ± 1.4 kg; 22 d) were housed 10 pigs per pen for a total of 48 pens and assigned within weight blocks to one of 4 dietary treatments (12 pens/diet). Pigs were fed 2 phases of experimental diets (0 – 8 d and 8 – 22 d post-weaning). Diets were corn-soybean meal-dry whey based and contained 4.35 and 4.10 g SID lysine/MCal ME for phases 1 and 2, respectively. The dietary treatments were, 1) basal diet with no additive [NC]; 2) NC + 50 ppm carbadox in phase 1, and 50 ppm neomycin + 50 ppm oxytetracycline in phase 2 [PC]; 3) NC + 50 ppm carbadox in phase 1, and 0.1% of Biotronic^® Top3 in phase 2 [C+OA]; 4) NC + 0.1% of Biotronic^® Top3 + 0.0125% of Digestarom^® P.E.P. [OA+EO] in both phases. Body weight and feed disappearance were measured weekly. A mixed model was used to examine the effect of diet, weight block was used as the random effect, and multiple comparisons were evaluated using t-test. Pigs receiving PC had greater BW (11.19 kg, P=0.001) compared to NC (10.53 kg), but did not differ from C+OA (11.03 kg, P=0.382) and OA+EO (10.85 kg, P=0.074) while BW did not differ between OA+EO and NC (P=0.100). Pigs fed PC (226 g/d) and C+OA (215 g/d) had higher ADG compared to NC (193 g/d, P ≤ 0.024), but they did not differ from pigs fed OA+EO (210 g/d, P≥0.101). Feed intake was not significantly different among groups (P=0.242). Gain to feed was increased with the addition of antibiotics and/or natural antimicrobials compared to NC (PC: 0.805, C+OA: 0.771, OA+EO: 0.774, NC: 0.722, P≤0.01). The present study suggests that Biotronic^® Top3 can be an effective tool to replace neomycin and oxytetracyline when pigs were previously fed carbadox during the first phase. In addition, the combination of Biotronic^® Top3 and Digestarom^® P.E.P. provided a viable natural alternative to replace in-feed antibiotics.