Live yeast and yeast extracts with and without pharmacological levels of zinc on nursery pig growth performance and antimicrobial susceptibilities of fecal Escherichia coli

Abstract

A total of 360 weanling barrows (Line 200 ×400, DNA, Columbus NE; initially 5.6 ± 0.03 kg) were used in a 42-d study to evaluate yeast-based pre- and probiotics (Phileo by Lesaffre, Milwaukee, WI) in diets with or without pharmacological levels of Zn on growth performance and antimicrobial resistance (AMR) patterns of fecal Escherichia coli. Pens were assigned to 1 of 4 dietary treatments with 5 pigs per pen and 18 pens per treatment. Dietary treatments were arranged in a 2 × 2 factorial with main effects of yeast-based pre- and probiotics (none vs. 0.10% ActiSaf Sc 47 HR+, 0.05% SafMannan, and 0.05% NucleoSaf from d 0 to 7, then concentrations were lowered by 50% from d 7 to 21) and pharmacological levels of Zn (110 vs. 3,000 mg/kg from d 0 to 7, and 2,000 mg/kg from d 7 to 21 with added Zn provided by ZnO). All pigs were fed a common diet from d 21 to 42 post-weaning. There were no yeast ×Zn interactions or effects from yeast additives observed on any response criteria. From d 0 to 21, and 0 to 42, pigs fed pharmacological levels of Zn had increased (P < 0.001) ADG and ADFI. Fecal samples were collected on d 4, 21, and 42 from the same three pigs per pen for fecal dry matter (DM) and AMR patterns of E. coli. On d 4, pigs fed pharmacological levels of Zn had greater fecal DM (P = 0.043); however, no differences were observed on d 21 or 42. E. coli was isolated from fecal samples and the microbroth dilution method was used to determine the minimal inhibitory concentrations (MIC) of E. coli isolates to 14 different antimicrobials. Isolates were categorized as either susceptible, intermediate, or resistant based on Clinical and Laboratory Standards Institute (CLSI) guidelines. The addition of pharmacological levels of Zn had a tendency (P = 0.051) to increase the MIC values of ciprofloxacin; however, these MIC values were still well under the CLSI classified resistant breakpoint for Ciprofloxacin. There was no evidence for differences (P > 0.10) for yeast additives or Zn for AMR of fecal E. coli isolates to any of the remaining antibiotics. In conclusion, pharmacological levels of Zn improved ADG, ADFI, and all isolates were classified as susceptible to ciprofloxacin although the MIC of fecal E. coli tended to be increased. Thus, the short-term use of pharmacological levels of Zn did not increase antimicrobial resistance. There was no response observed from live yeast and yeast extracts for any of the growth, fecal DM, or AMR of fecal E. coli criteria.

Effects of Tetrabasic Zinc Chloride on Growth Performance, Nutrient Digestibility and Fecal Microbial Community in Weaned Piglets

“…Post-weaning diarrhea (PWD) is one of the most common causes of stunted growth and mortality in piglets, causing huge economic losses to the pig industry. In practice, ZnO at pharmacological doses (2,000 mg Zn/kg or more) is widely applied to weaned piglet diets to prevent occurrences of PWD ( 3 , 26 ). In our study, dietary TBZC supplementation significantly reduced the diarrhea incidence in piglets, and its effect was comparable to that of the ZnO treatment group, which supports the previous finding that low-dose TBZC could effectively replace pharmacological doses of ZnO to alleviate diarrhea ( 6 ).…”

A buffalo rumen-derived probiotic (SN-6) could effectively increase simmental growth performance by regulating fecal microbiota and metabolism

“…Until now, many swine and poultry studies have demonstrated that probiotics help to develop healthy microflora (mainly probiotics), which prevent pathogen adhesion and invasion of intestinal epithelial cells, induce the production of antibacterial compounds, maintain epithelial barrier integrity, and regulate metabolism and immune system ( Wang et al, 2019 ; Šikić Pogačar et al, 2020 ; Chance et al, 2021 ). However, there is little evidence that ruminant-derived probiotics regulate gut microbial composition and thus affect metabolism to promote beef cattle body weight.…”

Summary of methodology used in enterotoxigenicEscherichia coli(ETEC) challenge experiments in weanling pigs and quantitative assessment of observed variability

“…The ordinal nature of this data makes sample size calculation difficult, thus, fecal DM may be a more suitable response to evaluate. Despite only one ETEC challenge study using the fecal DM approach, there are other published papers in nonchallenged pigs where fecal DM analysis was conducted ( Chance et al, 2021 ; Laskoski et al, 2021 ). Because these data are quantitative, they are typically presented in a form that allows scientists to extract measures of variability and means needed for sample size calculation.…”