Applicability of an Unmedicated Feeding Program Aimed to Reduce the Use of Antimicrobials in Nursery Piglets: Impact on Performance and Fecal Microbiota

• Main Authors: Paola López-Colom, Jordi Estellé, Jordi Bonet, Jaume Coma, Susana Ma. Martín-Orúe
• Format: Article
• Language: English
• Published: MDPI AG 2020-02-01
• Series: Animals
• Subjects: by-products; dietary fiber; fecal microbiota; gut health; in-feed antimicrobials; pig; post-weaning diarrhea; zno
• Online Access: https://www.mdpi.com/2076-2615/10/2/242

This study aimed to assess the impact of two different feeding programs, including or not antimicrobials, on gut microbiota development at early ages in commercial pigs. For this, 21-day-old weaned piglets were distributed into 12 pens (6 replicates with 26 pigs each) and fed ad libitum until fattening with: standard commercial formula with antibiotics and zinc oxide (2400 ppm) (AB), and alternative unmedicated feed formula (UN). Subsequently, the animals were moved to the fattening unit (F) receiving a common diet. Pigs were weighed, and feed consumption and diarrhea scores registered. Feces were collected on days 9 (pre-starter), 40 (starter) and 72 (fattening) post-weaning and microbial DNA extracted for 16S rDNA sequencing. Piglets fed UN diets had a worse feed efficiency (<i>p</i> &lt; 0.05) than AB during nursery; however, UN pigs spent less time scouring after weaning (<i>p</i> = 0.098). The structure of fecal community evolved with the age of the animals (<i>p</i> = 0.001), and diet also showed to have a role, particularly in the starter period when UN microbiomes clustered apart from AB, resembling the ecosystems found in the fattening animals. Fibrolytic genera (<i>Fibrobacter</i>, <i>Butyrivibrio</i>, Christellansellaceae) were enriched in UN piglets whereas <i>Lactobacillus</i> characterized AB piglets (adjusted <i>p</i> &lt; 0.05). Overall, this alternative feeding program could anticipate the gut development of piglets despite a lower feed efficiency compared to standard medicalized programs.