246. Effects of Probiotic Supplementation in DDGS Feeds on Splenic Gene Expression of Berkshire Pigs Finished in Hoop Barns.

Abstract

In this study, we evaluated the effects of a probiotic supplement in distiller’s dried grains with solubles (DDGS) feeds on the splenic transcriptome of Berkshire finisher pigs. At high levels, DDGS has been shown to reduce nutrient utilization, cause inflammation, and result increased adipose tissue which reduces carcass quality. Over a 35-day period that spanned August and September of 2024, twenty-four, 4-month old Berkshire pigs weighing 64.8±4.8 kg were randomly assigned to four diets: “15% DDGS” (Control), “15% DDGS + Probiotic” (Treatment 1), “15% DDGS + Xylanase (Treatment 2), and 15% DDGS + Probiotic/Xylanase (Treatment 3). This study focuses on the comparison of the splenic transcriptomes of pigs fed the “15% DDGS + Probiotic” (Treatment 1) diet and pigs fed the “15% DDGS” (Control) diet. The probiotic supplement (Lactobacillus) was added to the DDGS feed at a concentration of 1kg/ton. Spleens from these animals were harvested for RNA isolation, cDNA library construction, and RNA-sequencing using the NovaSeq X Plus platform from Illumina. The reads were mapped back to reference genome, Sscrofa11.1 and counted to assess differential expression (DE) (P ≤ 0.05, Log2 Fold Change ≥ 1.0) using DESeq2 package in the R Version 4.6.0. The Benjamini-Hochberg method was used to control for false positives. When comparing Treatment 1 to the Control, there were 579 differentially expressed genes, 297 up-regulated and 282 down-regulated. GO analysis was used to characterize the functions of the differentially expressed genes. The overrepresented functions among these differentially expressed genes were associated with anion transport, lipid localization, glycerolipid metabolic process, skeletal muscle contraction, pro-inflammatory cytokine and chemokine activity and the regulation of membrane-bound cell organization. We conclude that the addition of the probiotic supplement to the high-carbohydrate, DDGS diet results in increased uptake of glucose molecules by these Berkshire finishers. The spleen plays a role in lipid storage during metabolism, thus the inclusion of the “lipid localization” and “glycerolipid metabolic process” GO terms in the most overrepresented functions supports the spleen’s activity in lipid metabolism as a response to probiotic supplement in DDGS diets. Furthermore, past studies have been shown that lipid deposition from the consumption of high-carbohydrate diets has resulted in oxidation and peroxidation, causing inflammation and tissue damage. The inclusion of “pro-inflammatory cytokines” and “pro-inflammatory chemokines” in the GO analysis may be reflect this response. Ultimately, we conclude that the supplementation of probiotics to the 15% DDGS basal diet resulted in lipid accumulation and an inflammatory splenic response.