# Effects of Phytosterols on Growth Performance, Serum Indexes, and Fecal Microbiota in Finishing Pigs

## TL;DR

Phytosterols improve growth, immunity, and digestion in finishing pigs by enhancing nutrient absorption and altering gut bacteria.

## Contribution

This study demonstrates that phytosterols enhance growth performance and immunity in pigs through modulation of fecal microbiota.

## Key findings

- Phytosterols increased nutrient digestibility and average daily feed intake in finishing pigs.
- Phytosterols boosted antioxidant and immune markers like HDL-C, IgG, and SOD in pigs.
- Phytosterols altered gut microbiota by increasing Firmicutes and decreasing Acinetobacter.

## Abstract

Phytosterols, as a natural plant extract, have demonstrated efficacy in improving diabetes, lowering cholesterol levels, anti-inflammation, inhibiting bacteria, anti-oxidation, modulating immune responses, preventing cardiovascular disease, promoting wound healing, enhancing capillary circulation, and promoting animal growth. The results of this study indicate that phytosterols have a positive effect on nutrient digestion, oxidative stress and immunity in finishing pigs, and phytosterols may play a positive role by regulating fecal microbiota.

Phytosterols (PSs) are widely present in plants, particularly abundant in plant oils and seeds. PSs are reported to have various biological activities, such as lowering cholesterol, alongside antioxidant and antibacterial activities. This research examined the effects of PSs in finishing pigs, including growth performance, serum biochemistry, and fecal bacteria. Two treatment groups (each treatment group consisted of five biological replicates, and each replicate comprised five pigs housed communally) were randomly assigned to the fifty finishing pigs (equally divided by sex) of “Duroc × Landrace × Yorkshire” three-way cross with 79.76 ± 1.29 (kg) body weight. The control group (CON) was given basic food, while the experimental group was given basic food containing 300 mg PS/kg (PS). Dietary PS supplementation markedly raised the levels of average daily feed intake (ADFI) and apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE), and gross energy (GE) in comparison to the CON (p < 0.05). Additionally, PSs also significantly boosted the concentrations of high-density lipoprotein cholesterol (HDL-C), total protein (TP), catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), immunoglobulin G (IgG), motilin (MTL), and glucagon-like peptide-1 (GLP-1) (p < 0.05), and lowered the lactate dehydrogenase (LDH) level (p < 0.05). Both at the phyla and genus levels, the relative abundance of Firmicutes and Streptococcus increased significantly, and the relative abundance of Acinetobacter decreased significantly when adding phytosterols (p < 0.05). Overall, phytosterols dietary supplementation promotes immunity and antioxidant capacity in finishing pigs and boosts growth performance by improving nutrient digestibility.