# Effects of Raffinose on Growth Performance, Intestinal Function-Related Genes, and Cecal Microbiota in Broilers Fed Low Soybean Meal Diets

## TL;DR

This study explores how reducing soybean meal in broiler diets affects growth and gut health, and how adding raffinose can help mitigate negative effects.

## Contribution

The study introduces raffinose as a functional oligosaccharide that can partially counteract the negative impacts of low soybean meal diets on broiler performance and gut microbiota.

## Key findings

- A low soybean meal diet increased mortality and reduced nutrient utilization in broilers.
- Raffinose supplementation improved gut microbiota balance and reduced mortality.
- Raffinose altered gene expression and cecal acid content in broilers.

## Abstract

The modern broiler industry is crucial for supplying high-quality animal protein globally, yet this industry requires a large amount of expensive and resource scarce soybean meal (SBM) as a source of feed protein. Reducing the amount of SBM in broiler feed is a great challenge. In this context, we first used a low SBM diet to investigate the effects of functional oligosaccharides (raffinose) in SBM on the productive performance, intestinal health, and gut microbiota in broiler chickens. Raffinose can pass intact into the hindgut, acting as a specific nutrient for beneficial bacteria such as Bifidobacterium and Lactobacillus. The results showed that low SBM diet application in white-feathered broiler diets need to consider the content of functional soybean oligosaccharide, which provide a new perspective for reducing SBM consumption in the poultry feed industry.

This study investigated the effects of a low soybean meal (SBM) diet and its supplementation with graded levels of raffinose on the growth performance, expression of genes related to nutrient transport and intestinal function, and cecal microbiota of white-feathered broilers. A total of 480 one-day-old Cobb broilers were randomly allotted to six isoenergetic and isonitrogenous dietary treatments, each with eight replicates of 10 birds. The diets consisted of a positive diet, a low SBM diet (10% reduction in SBM), and the low SBM diet supplemented with 0.10%, 0.15%, 0.20%, or 0.25% raffinose. Results indicated that, compared with the positive diet, the low SBM diet significantly increased (p < 0.05) the overall mortality and average daily feed intake (ADFI) during days 22–42, while significantly decreasing (p < 0.05) dietary ether extract (EE) availability. Raffinose supplementation to the low SBM diet linearly reduced (p < 0.05) dietary gross energy and dry matter utilization and downregulated duodenal SLC5A1 gene expression at 42 days, while linearly increasing (p < 0.05) the cecal isobutyric acid content. A decreasing tendency in mortality during days 22–42 was also observed with raffinose inclusion (p = 0.088). Notably, the low SBM diet elevated the relative abundance of Campylobacterota and Helicobacter, which was effectively reversed by raffinose supplementation. In conclusion, a 10% reduction in dietary SBM negatively affected the survival, nutrient utilization, and cecal microbial structure in broilers, whereas raffinose supplementation partially modulated these alterations.