Prevention of excessive exercise-induced adverse effects in rats with Bacillus subtilis BSB3

Aims

To characterize efficacy of the Bacillus subtilis BSB3 (BSB3) strain in the prevention of excessive exercise‐induced side effects and in maintaining stability of the gut microbiota.

Methods and Results

Rats were pretreated by oral gavage with B. subtilis BSB3 (BSB3) or with phosphate‐buffered saline (PBS) twice a day for 2 days, and were either exposed forced treadmill running or remained sedentary. Histological analysis of intestine, immunofluorescence staining of tight junction (TJ) proteins, serum lipopolysaccharide and intestinal fatty acid‐binding protein assay, culture‐based analysis and pyrosequencing for the gut microbiota were performed for each rat. Forced running resulted in a substantial decrease in intestinal villi height and total mucosa thickness, the depletion of Paneth cells, an inhibition of TJ proteins expression. Short‐term treatment of rats with BSB3 before running prevented these adverse effects. Culture‐based analysis of the gut microbiota revealed significant elevation of pathogenic microorganisms only in treadmill‐exercised rats pretreated with PBS. High‐throughput 16S rRNA gene sequencing also revealed an increase in pathobionts in this group. Preventive treatment of animals with BSB3 resulted in predominance of beneficial bacteria.

Conclusions

BSB3 prevents excessive exercise‐associated complications by beneficial modulation of the gut microbiota.

Significance and Impact of the Study

Our study shows a new application of beneficial bacteria for prevention the adverse effects of excessive exercise.

Effect of reducing the ratio of omega-6-to-omega-3 fatty acids in diets of low protein quality on nursery pig growth performance and immune response

A total of 240 newly weaned pigs (5.25 ± 0.15 kg BW) were used to determine the dietary omega-6-to-omega-3 (ω-6:ω-3) fatty acid ratio that optimized growth performance and immune responses when fed corn and soybean meal (SBM)-based diets with low protein quality. Pigs were randomly assigned to 1 of 5 dietary treatments (n = 6 pens per treatment; day 0 of study): [1] positive control (High; included animal proteins and 5% corn oil), [2] negative control (Low0; corn- and SBM-based and 5% corn oil), or 1 of 3 Low diets with increasing supplementation of fish oil to replace corn oil: [3] 1.25% (Low1.25), [4] 2.5% (Low2.5), [5] 5% (Low5) to achieve 5:1, 3:1, and 1:1 ω-6:ω-3 ratios, respectively. Pigs were fed dietary treatments in 2 phases for 7 and 14 d, respectively, followed by a common phase III diet for 21 d. On day 6 and 20, 12 pigs per treatment were immune sensitized with 0.5 mg ovalbumin (OVA) and 0.5 mg Quil A adjuvant in 1 mL saline. The dermal hypersensitivity response (DHR) was evaluated on day 40 in these same pigs, using intradermal injection of OVA; changes in skin-fold thickness were measured. On day 21, 4 pigs per pen were immune challenged with LPS (30 µg Escherichia coli LPS per kg BW) or saline (n = 12); rectal temperature was monitored over 3 h. During phase I only, ADG, ADFI, and G:F were greater for pigs fed the High diet vs. those fed the Low diet (P < 0.05), and increased with increasing fish oil supplementation up to 2.5% (Low2.5), but decreased for pigs fed the Low5 diet (quadratic; P < 0.05, P = 0.086, and P < 0.05 for ADG, ADFI, and G:F, respectively). On day 21, LPS increased rectal temperature (vs. saline at 1-, 2-, and 3-h post-challenge; P < 0.001); fish oil supplementation reduced rectal temperature 2-h post-challenge in the Low-fed pigs (linear; P < 0.05). On day 22, serum haptoglobin was greatest for pigs fed Low0 and decreased with increasing fish oil supplementation (linear; P < 0.05). Immunization with OVA induced a serum anti-OVA IgG response, which was reduced on day 34 among pigs fed Low diets with increasing fish oil supplementation (linear; P = 0.050). On day 40, and 6 h after intradermal injection of OVA, the DHR was least for pigs fed the Low2.5 diet (P < 0.05). Inclusion of 2.5% fish oil (3:1, ω-6:ω-3) optimized growth performance during the early nursery phase when pigs were most sensitive to diets with low protein quality; the ideal ω-6-to-ω-3 fatty acid ratio may differ when using immune responses as the major outcome.