# Effect of a Multi-Species Direct-Fed Microbial on Growth Performance, Nutrient Digestibility, Intestinal Morphology and Colonic Volatile Fatty Acids in Weanling Pigs

## TL;DR

A new microbial supplement improved growth, digestion, and gut health in young pigs better than antibiotics or enzymes.

## Contribution

A multi-species direct-fed microbial outperformed antibiotics and enzymes in enhancing piglet growth and digestion.

## Key findings

- DFM increased final body weight by 3 kg compared to the control group.
- DFM improved apparent ileal digestibility of essential amino acids more than antibiotics or enzymes.
- DFM enhanced intestinal morphology and colonic volatile fatty acid production, improving gut health.

## Abstract

Supplementing the ration of weanling pigs for 6 weeks with a novel commercial multi-species direct-fed microbial (DFM) based on cell-wall deficient Lactobacillus spp. and Bacillus subtilis showed a greater apparent ileal digestibility (AID) of essential amino acids (EAAs) consisting of Arg, Ile, Thr and Val compared to in-feed antibiotics (ABO) and multi-enzyme complex (ENZ) group. The improvement in growth performance and crude protein (CP) digestion of piglets fed with DFM can be attributed to several mechanisms. First, growth performance may be linked to nutrient utilization, as evidenced by the increased AID of CP and EAA in piglets fed DFM. Second, pigs fed diets containing DFM had a greater intestinal villus height, which may suggest improved digestive and absorptive capabilities. Third, metabolites from DFM can contribute to colonic volatile fatty acid (VFA) production and the regulation of systemic immune responses, contributing to energy salvage, the inhibition of opportunistic pathogens and protection against inflammation. Fourth, DFM modulate the activities of digestive enzyme and boost digestive capacity in weanling pigs, which may positively influence animal health.

The potentials of ABO replacer of ENZ and DFM on growth performance, AID, colonic VFAs, gut morphology, fecal score and diarrhea incidence were evaluated. We randomly assigned 120 piglets to four experimental diets that included: (1) control diet (CON), fed the basal ration; (2) ABO was added at 250 ppm of in-feed ABO; (3) ENZ was added at a rate of 3 kg/ton feed; (4) DFM was added with 50 × 106 cfu/g of Bacillus subtilis and 2 × 106 cfu/g of Lactobacillus spp. at a rate of 1.2 kg/ton feed. A complete randomized design used six pens per treatment with five pigs per pen. Pigs had ad libitum access to feed and water throughout the 6-week trial. Feed intake and BW were recorded on weeks 0, 2, 4 and 6, as well as fecal scores and diarrhea incidences (visually recorded and calculated). At weeks 2 and 4, a sub-sample of pigs (n = 6) was sacrificed for intestinal morphology, enzyme activity and VFAs. The results of the study demonstrated that DFM piglets showed increased final BW (3 kg) (p < 0.001) vs. CON. Likewise, ADG was positively affected by the incorporation of ABO, ENZ and DFM in the diets, with an average increase of 8 to 17% on ADG compared with CON (p < 0.001). The AID of gross energy, organic matter, CP and EAAs in piglets fed ENZ and DFM were significantly higher (p < 0.05) than those of CON and ABO at weeks 2 and 4. Inclusion of DFM increased intestinal morphology, enzymatic activities and propionic and butyric acid more than in pigs fed CON, ABO and ENZ (p < 0.05). The fecal score and diarrhea incidence generally decreased over time in pigs fed DFM (p < 0.05). These findings indicate that dietary supplementation with DFM has better effects at any period on growth performance, CP and AA digestibility and beneficially altered the intestinal health in weanling piglets.