Mariam Kachlek

The metabolic capacity of swine caecum-derived Lactobacillus spp. to biotransform mycotoxins presents promising potential as a host-probiotic strategy to improve pig health and support host-targeted probiotic research. In the present study, Lactobacillus spp. isolated from the pig caecum were examined for their ability to detoxify fumonisin B1 (FB1) in vitro. Three experimental groups were established (i) Control 1 (C1: buffer + caecal chyme), (ii) Control 2 (C2: buffer + FB1), (iii) Experimental group (E: buffer + caecal chyme + FB1), each with 12 replicates per group (4 replicates per time point 0, 24, and 48 h). Quantitative polymerase chain reaction (qPCR) was used to determine bacterial abundance, while fumonisin B1 (FB1) and its hydrolyzed product (HFB1, Hydrolyzed Fumonisin B1), were quantified using liquid chromatography–mass spectrometry (LC-MS). Group E showed a significant increase in Lactobacillus spp. abundance (p < 0.001), indicating a selective microbial response to FB1 exposure. In contrast, total bacterial counts did not differ significantly between C1 and E (p = 0.35), suggesting that the proliferation of Lactobacillus was the main microbiological outcome supporting the host–probiotic hypothesis. Principal component analysis (PCA) revealed distinct microbial clustering, explaining 97.3% of the variance. Compared to C2, FB1 levels in group E were significantly reduced at 24 and 48 h, while HFB1 conversion rates increased from 47.1% to 56.5%. The study identified Lactobacillus pontis, Lactobacillus amylovorus, and Lactobacillus ultunensis as promising host-associated probiotics, with potential application as feed additives to mitigate mycotoxin effects in pigs. These findings warrant further in vivo validation.

Fumonisin-producing fungal species, Fusarium verticillioides , culture was mixed in the diets of 6 piglets for 9 days (Fumonisin B ₁ [FB ₁ ] intake of 17 mg/kg) to investigate whether there is any potential alteration in the caecal bacterial communities between the experimental (with F. verticillioides ) and control groups (without F. verticillioides ). Plate count agar culturing technique was applied to measure the amount of aerobic and anaerobic bacteria, Escherichia coli , coliforms, Lactobacillus spp. and Clostridium perfringens . A significant difference was observed between the control and experimental group only in the case of aerobic bacteria on Day 4, 8.60 ± 0.22 compared to 8.06 ± 0.20 ( P < 0.05), respectively. Quantitative polymerase chain reaction (qPCR) was performed to estimate the DNA copy number of total bacteria, Bacteroides and Prevotella spp., Clostridium spp., E. coli , Enterobacteriales , Firmicutes and Lactobacillus spp. Significant differences were observed between the control and experimental group regarding total bacteria on Day 2 and Day 6, Firmicutes on Day 2 and E. coli and Enterobacteriales on Day 4. Regarding the entire feeding time, no significant difference between the two groups was found in all species of investigated bacteria by the culturing technique and qPCR after an 8-day exposure. The present research contributes to the understanding of how microbiota responds to the FB ₁ load.

Male Wistar rats were treated intraperitoneally (i.p.) with fumonisin B₁ (FB₁; 0, 20, 50 and 100 mg/kg dietary dose equivalent) for 5 and 10 days (n = 24–24 in each setting) to gain dose- and time-dependent effects on antioxidant status and oxidative stress response, clinical chemical endpoints and liver, kidney and lung histopathology and lymphocyte damage (genotoxicity). FB₁ decreased feed intake, body weight gain and absolute liver weight, irrespective of the toxin dose. Relative kidney weight increased in the 10-day setting. Linear dose response was found for plasma aspartate aminotransferase, alanine aminotransferase, total cholesterol, urea and creatinine, and exposure time-dependence for plasma creatinine level. The latter was coupled with renal histopathological findings, tubular degeneration and necrosis and the detachment of tubular epithelial cells. The pronounced antioxidant response (reduced glutathione accretion, increasing glutathione peroxidase activity) referred to renal cortical response (5–10 days exposure at 50–100 ppm FB₁). Hepatic alterations were moderate, referring to initial phase lipid peroxidation (exposure time dependent difference of conjugated diene and triene concentrations), and slight functional disturbance (↑ total cholesterol). Lymphocyte DNA damage was moderate, supporting a mild genotoxic effect of FB₁.

Conventional analytical methods used for the analysis of fumonisin content in animal feeds fail to take into account the fumonisin content bound to the matrix, which is otherwise bioaccessible and can be absorbed from the gastrointestinal tract. Moreover, underestimation of fumonisin content using routine analytical methods can affect animal experiments using cereals contaminated by fungi. In the present study, hidden fumonisin B₁ was analysed in two cereal substrates (maize and wheat) which were inoculated withFusarium verticillioides (MRC 826). The study compared a routine extraction procedure with anin vitro digestion sample pre-treatment. We found that all samples showed a higher content of fumonisin B₁ after digestion, compared to the free fumonisin obtained only by extraction. The percentage of the hidden form was 38.6% (±18.5) in maize and 28.3% (±17.8) in wheat, expressed as the proportion of total fumonisin B₁. These results indicate that the toxin exposure of the animals determined by the routine fumonisin analysis was underestimated, generally by 40%, as bioaccessibility was not taken into consideration. This is crucial in interpretation (and maybe in re-evaluation) of the results obtained from (other) animal experiments.