Evaluating dietary acidifiers as alternatives for conventional feed-based antibiotics in nursery pig diets

Abstract

A total of 360 weanling pigs (DNA 200 × 400; initially 9.7 ± 0.23 kg BW) were used in a 21-d experiment with 6 pigs/pen, 10 replicate pens/treatment, and 2 separate nursery rooms, each with 30 pens. Pigs were weighed and allotted to pens based on BW in a completely randomized block design to one of 6 treatment diets: 1) Negative control (no organic acids or antibiotics) and the control with 2) 0.25% Acidifier A; 3) 0.3% Acidifier B; 4) 0.5% Acidifier C); 5) 50 g/t Carbadox; 6) 400 g/t Chlortetracycline. Upon weaning, a common diet with no antibiotics or additives was fed for 21 d (phases 1 and 2; d -21 to d 0), followed by a 21 d experimental period (phase 3; d 0 to d 21) where treatment diets were fed. Pigs and feeders were individually weighed on a weekly basis to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency (G:F). Data were analyzed using the PROC GLIMMIX procedure of SAS (v 9.4, SAS Inst., Cary, NC) with pen as the experimental unit, treatment as a fixed effect and room as a random effect. Dietary treatment had a significant impact (P < 0.05) on ADG, ADFI and G:F each week and for the overall experimental period (d 0 to 21). Specifically, from d 0 to 7, pigs fed CTC had increased (P = 0.001) ADG compared to those fed Acidifier B, Acidifier C and Carbadox, while pigs fed the negative control and Acidifier A diets were intermediate. Additionally, pigs fed the CTC diet had improved (P = 0.0002) ADFI when compared to all other treatments. From d 7 to 14 and d 14 to 21, pigs fed the Carbadox diet had decreased (P < 0.0001) ADG compared to all other treatments. During the overall period (d 0 to 21), pigs fed diets containing Carbadox had reduced ADG and ADFI (P < 0.0001), while pigs fed CTC had improved (P < 0.0001) ADG compared to all other treatments. Additionally, blood parameters, fecal consistency and fecal microbial populations were analyzed on a subset of pigs (n = 5 pigs/treatment). Dietary treatment significantly impacted (P < 0.05) concentrations of protein, globulin, phosphorus, alkaline phosphatase, and sorbitol dehydrogenase in the blood. Treatment also significantly impacted (P = 0.0005) fecal score but did not affect (P = 0.59) fecal microbial growth from d 0 to 21. In summary, CTC continues to be a valuable additive to improve performance in the nursery. Further investigation surrounding the efficacy of dietary acidifiers as antibiotic alternatives is warranted given inconclusive evidence in this study.

Acidifiers and prebiotics in the diets of nursery-stage piglets as alternatives to antibiotic growth promoters

“…Regarding acids as additives, most dietary acids are used in the condition of blends, and their responses depend on the level of inclusion, dietary components and nutritional characteristics (Dahmer & Jones, 2021). In parallel, prebiotics derived from the cell wall of the yeast Saccharomyces cerevisiae, such as beta-glucans and mannan oligosaccharides, are important representatives of this class of additives.…”