Transcriptome Analysis of Spleen in Chickens Administered β-glucan Derived From Yeast Cell Wall

Background: Our previous study shown that oral administration of a product contained yeast cell wall polysaccharides enhanced immune responses elicited by Newcastle disease virus and changed microbial community of cecum in chickens.Results: The present study was design to investigate the potential molecular mechanism in relation to the immunomodulation of β-glucan in chickens. Using RNA-sequence (RNA-seq) technique, we identified 198 DEGs in spleen in chickens after oral administration of β-glucan. In addition, these DEGs were significantly enriched in 205 GO terms and 7 KEGG pathways. Conclusions: β-glucan might regulate chicken immune system by regulating expression of genes involved in cognition, cytokines, binding, enzyme activities and multiple signaling pathway.

PSIX-21 Assessment of barrier function and cell junctional expression on differentiated intestinal porcine epithelial cells in response to Salmonella LPS challenge and treatment with Yeast cell wall products

Mannan rich fractions were previously demonstrated to improve junctional gene expression which can reduce leaky intestinal tracts that facilitate bacterial infection in piglets. The work here assessed MRF and other yeast mannan products’ effects on intestinal barrier function in response to bacterial challenge from Salmonella LPS. Differentiated IPEC cells were grown to 14 days until a trans-epithelial electrical resistance reading (TEER) of ~ 4500 Ohms/cm2 was reached. Prior to lipopolysaccharide (LPS) (1µg/mL) challenge, cells were pre-treated and post-treated with MRF or yeast products A, B, and C (16mg/mL). Post treated cells were lysed in RLT buffer and RNA isolated (RNeasy). RIN values above 7 were used to synthesise cDNA (SuperScript®-III). Junctional genes Occludin, Claudin3 and Tight junction protein1 (TJP1) were assessed by qPCR (Applied Biosystems 7500 Fast). TNFα proinflammatory secretion was measured by ELISA. Three independent biological replicates were performed, with One-way ANOVA carried out unless stated otherwise. TEER results showed MRF significantly recovered barrier function (5090.3±187.0, P ≤ 0.05) over the positive control (PC) (3754.2±605.8) while product A (3502.5±182.7749), B (3414.289±733.8854) and C (3938.4±491.4) demonstrated no significant improvement to the PC. MRF treated cells were significantly higher for Claudin3 gene expression (1.33±0.18, P ≤ 0.05) over the control (0.671661±0.277) and treatments A (0.53±0.16, P ≤ 0.05), B (0.91±0.18, P ≤ 0.05) and C (0.69±0.25, P ≤ 0.05). Occludin expression was significantly higher in MRF treated cells (1.09±0.01, P ≤ 0.05) over the PC (0.89±0.09, P ≤ 0.05) and treatment B (0.88±0.04, P ≤ 0.05). TJP-1 gene expression was highest in the MRF treated cells (1.30±0.41) but not significantly, compared to the PC (1.00±0.14). TNFα (pg/mL) protein secretion was significantly lower in both the MRF treated (0.0809±0.86x10-3, P ≤ 0.05) and treatment C 0.081±0.18 x10-3, P ≤ 0.05) over the PC (0.0813±0.22x10-3). MRF augmented junctional expression improving TEER readings and potentially lessened LPS intracellular leakage that led to lower proinflammatory protein secretion. The present study highlights differences in efficacy of a variety of yeast cell wall products.

Dietary Yeast Cell Wall Improves Growth Performance and Prevents of Diarrhea of Weaned Pigs by Enhancing Gut Health and Anti-Inflammatory Immune Responses

Dietary yeast cell wall products (YCW) are recognized as a feed additive due to multifunctional benefits by the biological response modulators. Thus, this study was conducted to verify a potential advantage of YCW for improving growth performance, nutrient digestibility, immune responses, and intestinal health and microbiota of weaned pigs. A total of 112 weaned pigs (7.99 ± 1.10 kg of body weight; 28 days old) were arbitrarily allocated to two experimental treatments with eight pigs (four barrows and four gilts) per pen and seven replicate pens per treatment in a completely randomized block design (block = BW and sex): (1) a basal diet based on corn and soybean meal (CON) and (2) CON + 0.05% YCW. The experimental period was for 4 weeks. There were no differences in final body weight, average daily feed intake, and gain-to-feed ratio between dietary treatments. In contrast, pigs fed YCW had higher average daily gain (p = 0.088) and apparent ileal digestibility of DM (p < 0.05) and energy (p = 0.052) and lower diarrhea frequency (p = 0.083) than those fed control diet (CON). Pigs fed YCW also had a higher (p < 0.05) ratio between villus height and crypt depth, villus width and area, and goblet cell counts in the duodenum and/or jejunum than those fed CON. Dietary YCW decreased (p < 0.05) serum TNF-α and IL–1β of weaned pigs on day 7 and 14, respectively, compared with CON. Furthermore, pigs fed YCW had higher (p < 0.05) ileal gene expression of claudin family, occludin, MUC1, INF-γ, and IL-6 and lower (p < 0.05) that of TNF-α than those fed CON. Lastly, there were no differences in the relative abundance of bacteria at the phylum level between CON and YCW. However, dietary YCW increased (p < 0.05) the relative abundance of genera Prevotella and Roseburia compared with CON. This study provided that dietary YCW improved growth rate, nutritional digestibility, and intestinal health and modified immune responses and intestinal microbiota of weaned pigs.

Mitigation of AFB1-Related Toxic Damage to the Intestinal Epithelium in Broiler Chickens Consumed a Yeast Cell Wall Fraction

In vivo experiments were conducted to evaluate the effectiveness of a yeast cell wall fraction (YCW) to reduce the negative impact of aflatoxin B1 (AFB1) to the intestinal epithelium in broiler chickens. Zeta potential (ζ-potential), point of zero charge (pHpzc), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) techniques were used to characterize the YCW. Two hundred one-day-old male Ross 308 broiler chickens were randomly allocated into four treatments: (1) control, chickens fed an AFB1-free diet; (2) AF, chickens feed an AFB1-contaminated diet (500 ng AFB1/g); (3) YCW, chickens fed an AFB1-free diet + 0.05% YCW; and (4) AF + YCW, chickens fed an AFB1-contaminated diet (500 ng AFB1/g) + 0.05% YCW. At the end of the 21-day feeding period, fluorescein isothiocyanate dextran (FITC-d) was administered to chicks by oral gavage to evaluate gastrointestinal leakage. Blood and duodenum samples were collected to assess serum biochemistry and histomorphology, respectively. Compared to the control group, chicks of the AF group significantly diminished weight gain (WG) and average daily feed intake (ADFI), and increased feed conversion ratio (FCR), mortality rate (MR), and intestinal lesion scores (p &lt; 0.05). Alterations in some serum biochemical parameters, and damage to the intestinal integrity were also evident in the AF-intoxicated birds. YCW supplementation improved WG and FCR and increased villus height, villus area, crypt depth, and the number of goblet cells in villi. The effects of YCW on growth performance were not significant in chicks of the AF + YCW group; however, the treatment decreased MR and significantly ameliorated some biochemical and histomorphological alterations. The beneficial effect of YCW was more evident in promoting gut health since chickens of the AF + YCW group presented a significant reduction in serum FITC-d concentration. This positive effect was mainly related to the changes in negative charges of YCW due to changes in pH, the net negative surface charge above the pHpzc, the higher quantities of negative charged functional groups on the YCW surface, and its ability to form large aggregates. From these results, it can be concluded that YCW at low supplementation level can partially protect broilers' intestinal health from chronic exposure to AFB1.