# Effects of a saccharomyces yeast postbiotic on growth performance and carcass traits of pigs fed diets with divergent protein content

## TL;DR

A yeast postbiotic supplement improved pig growth efficiency and carcass traits when added to high-protein diets.

## Contribution

This study shows a Saccharomyces yeast postbiotic improves feed conversion and lean carcass traits in pigs.

## Key findings

- SYP+ pigs had improved feed conversion efficiency in phases 1 and 4.
- SYP+ carcasses had greater dressing percent and lower marbling scores.
- SYP+ pigs showed reduced phase-4 average daily feed intake.

## Abstract

The objective of this study was to determine effects of a Saccharomyces yeast postbiotic (SYP) on pig growth performance and carcass traits when added to diets containing elevated- and commercial-protein contents during growing and finishing phases. Pigs (N = 51 barrows and 57 gilts; initial BW 28.3 ± 3.5 kg) were weighed, stratified by weight within sex, and within each 18-pig strata pigs were randomly assigned to a pen (N = 18; N = 6 pigs/pen). Pens were randomly assigned to one of two dietary treatments (TRT) consisting of 0- (SYP-) or 100-ppm SYP (SYP+) mixed in a four-phase dietary regimen (phase 1, d 0 to 21; phase 2, d 22 to 42; phase 3, d 43 to 63; phase 4, d 64 to 84). Feed consumption and body weight (BW) were collected weekly to calculate average daily gain (ADG) and average daily feed intake (ADFI). Pigs were harvested over three harvest blocks where the heaviest male and female from each pen were harvested and carcass data were collected 24-h postmortem. During all four phases, there were no TRT effects on BW, ADG, and ADFI (P > 0.12), except SYP + pigs had less (P = 0.04) phase-4 ADFI. There was no TRT effect (P = 0.86) on phase-2 G: F, but SYP + pigs had greater phase-1 and -4 G: F and smaller phase-3 G: F (P < 0.04). Carcasses from SYP + pigs tended to have greater (P = 0.09) HCW and had greater (P < 0.01) dressing percent than SYP- carcasses. There were no TRT treatment effects for 10th or last rib fat thickness (P > 0.13), but SYP + carcasses tended to have less (P = 0.07) first rib fat thickness. There were no TRT effects on loin eye area, objective- and subjective-color scores (P > 0.24). Carcasses from SYP + had smaller NPB marbling and Japanese marbling color scores than SYP- carcasses (P < 0.02). This SYP mainly enhanced feed conversion efficiency and lean-derived carcass traits when added to an elevated-protein diet.

This study demonstrated a Saccharomyces yeast postbiotic supplement enhanced pig growth efficiency and possibly protected against intestinal disease. These findings provide producers with information on dietary protein content and disease effects on the SYP response.