Effects of Dietary β-Glucan on Growth Performance, Diarrhea, and Gut Permeability of Weanling Pigs Experimentally Infected with a Pathogenic E. coli

ProGlucan^TM is 100% dried algae, Euglena gracillus, which contains approximately 54% β-1,3-glucan. The objective of this experiment was to investigate the influence of dietary supplementation of ProGlucan on growth performance, diarrhea score, and gut permeability of weaned pigs experimentally infected with a pathogenic F-18 E. coli. Weaned pigs (n = 36, 7.69 ± 0.77 kg BW) were individually housed in disease containment rooms and randomly allotted to one of three dietary treatments with 12 replicate pigs in each treatment. The three diets were a nursery basal diet (control), and 2 additional diets containing either 100 or 200 mg/kg of ProGlucan in the basal diet. The experiment lasted 17 d [5 d before and 12 d after the first inoculation (d 0)]. The inoculum used in this experiment was F-18 E. coli, containing LT, STb, and SLT-2 toxins. The inoculation doses were 10¹⁰ cfu/3 mL oral dose daily for 3 days. The growth performance was measured on d 0 to 5, 5 to 12, and 0 to 12 post-inoculation (PI). Diarrhea score (DS; 1, normal, to 5, watery diarrhea) was recorded for each pig daily. Frequency of diarrhea was the percentage of pig days with DS of 4 or higher. Rectal temperature was measured for each pig daily after first inoculation. On d 5 and d 12, jejunum were collected from 4 pigs in the control group and high dose ProGlucan group for transcellular and paracellular permeability analysis. All data were analyzed by ANOVA using the PROC MIXED of SAS with pig as the experimental unit. The Chi-square test was used for the frequency of diarrhea analysis. No differences were observed in growth rate and feed intake of E. coli-challenged pigs throughout the experiment. Pigs fed 100 mg/kg ProGlucan had lower (P < 0.05) rectal temperature compared with pigs fed the control diet on d 5 and 7 PI. Inclusion of 200 mg/kg ProGlucan reduced (P < 0.05) frequency of diarrhea (9.26 vs. 17.90%) for the entire experimental period and decreased (P < 0.05) transcellular permeability on d 12 PI compared with the control diet. In conclusion, supplementation of ProGlucan may enhance disease resistance of weaned pigs, as indicated by reducing frequency of diarrhea and gut permeability.