Physiological Effects of Deoxynivalenol from Naturally Contaminated Corn on Cerebral Tryptophan Metabolism, Behavioral Response, Gastrointestinal Immune Status and Health in Pigs Following a Pair-Feeding Model

Development and application of a multi-step porcine in vitro system to evaluate feedstuffs and feed additives for their efficacy in nutrient digestion, digesta characteristics, and intestinal immune responses

In vitro model provides alternatives to the use of live animals in research. In pig nutrition, there has been a tremendous increase in in vivo research over the decades. Proper utilization of in vitro models could provide a screening tool to reduce the needs of in vivo studies, research duration, cost, and the use of animals and feeds. This study aimed to develop a multi-step porcine in vitro system to simulate nutrient digestion and intestinal epithelial immune responses affected by feedstuffs and feed additives. Seven feedstuffs (corn, corn distillers dried grains with solubles [corn DDGS], barley, wheat, soybean meal, soy protein concentrates, and Corynebacterium glutamicum cell mass [CGCM]), feed enzymes (xylanase and phytase), and supplemental amino acids (arginine, methionine, and tryptophan), were used in this in vitro evaluation for their efficacy on digestibility, digesta characteristics, and intestinal health compared with the results from previously published in vivo studies. All in vitro evaluations were triplicated. Data were analyzed using Mixed procedure of SAS9.4. Evaluations included (1) nutrient digestibility of feedstuffs, (2) the effects of feed enzymes, xylanase and phytase, on digestibility of feedstuffs and specific substrates, and (3) the effects of amino acids, arginine, tryptophan, and methionine, on anti-inflammatory, anti-oxidative, and anti-heat stress statuses showing their effects (P < 0.05) on the measured items. Differences in dry matter and crude protein digestibility among the feedstuffs as well as effects of xylanase and phytase were detected (P < 0.05), including xylo-oligosaccharide profiles and phosphorus release from phytate. Supplementation of arginine, tryptophan, and methionine modulated (P < 0.05) cellular inflammatory and oxidative stress responses. The use of this in vitro model allowed the use of 3 experimental replications providing sufficient statistical power at P < 0.05. This indicates in vitro models can have increased precision and consistency compared with in vivo animal studies.

Identification and characterization of Achromobacter spanius P-9 and elucidation of its deoxynivalenol-degrading potential

Deoxynivalenol (DON) poses significant challenges due to its frequent contamination of grains and associated products. Microbial strategies for mitigating DON toxicity showed application potential. Eight bacterial isolates with DON degradation activity over 5% were obtained from various samples of organic fertilizer in this study. One of the isolates emerged as a standout, demonstrating a substantial degradation capability, achieving a 99.21% reduction in DON levels. This isolate, underwent thorough morphological, biochemical, and molecular characterization to confirm its identity, and was identified as a new strain of Achromobacter spanius P-9. Subsequent evaluations revealed that the strain P-9 retains its degradation activity after a 24-h incubation, reaching optimal performance at 35 °C with a pH of 8.0. Further studies indicated that Ca2+ ions enhance the degradation process, whereas Zn2+ ions exert an inhibitory effect. This is the pioneering report of DON degradation by Achromobacter spanius, illuminating its prospective utility in addressing DON contamination challenges.

Glycyrrhinic acid and probiotics alleviate deoxynivalenol-induced cytotoxicity in intestinal epithelial cells

Deoxynivalenol (DON) is one of the most prevalent mycotoxin contaminants, which posing a serious health threat to animals and humans. Previous studies have found that individually supplemented probiotic or glycyrrhinic acid (GA) could degrade DON and alleviate DON-induced cytotoxicity. The present study investigated the effect of combining GA with Saccharomyces cerevisiae (S. cerevisiae) and Enterococcus faecalis (E. faecalis) using orthogonal design on alleviating IPEC-J2 cell damage induced by DON. The results showed that the optimal counts of S. cerevisiae and E. faecalis significantly promoted cell viability. The optimal combination for increasing cell viability was 400 µg/mL GA, 1 × 10⁶ CFU/mL S. cerevisiae and 1 × 10⁶ CFU/mL E. faecalis to make GAP, which not only significantly alleviated the DON toxicity but also achieved the highest degradation rate of DON (34.7%). Moreover, DON exposure significantly increased IL-8, Caspase3 and NF-κB contents, and upregulated the mRNA expressions of Bax, Caspase 3, NF-κB and the protein expressions of Bax, TNF-α and COX-2. However, GAP addition significantly reduced aforementioned genes and proteins. Furthermore, GAP addition significantly increased the mRNA expressions of Claudin-1, Occludin, GLUT2 and ASCT2, and the protein expressions of ZO-1, Claudin-1 and PePT1. It was inferred that the combination of GA, S. cerevisiae, and E. faecalis had the synergistic effect on enhancing cell viability and DON degradation, which could protect cells from DON-induced damage by reducing DON cytotoxicity, alleviating cell apoptosis and inflammation via inhibiting NF-κB signaling pathway, improving intestinal barrier function, and regulating nutrient absorption and transport. These findings suggest that GAP may have potential as a dietary supplement for livestock or humans exposed to DON-contaminated food or feed.

Urinary and Serum Concentration of Deoxynivalenol (DON) and DON Metabolites as an Indicator of DON Contamination in Swine Diets

Pig health is impaired and growth performance is reduced when exposed to deoxynivalenol (DON). The measurement of DON in individual feedstuffs and complete swine diets is variable because of the inconsistent distribution of mycotoxins in feed and the difficulties in obtaining representative samples. We investigated whether measuring DON and its metabolites in biological samples could be used as a predictor of DON ingestion by pigs. Blood samples were collected between 3 and 4 h after the morning meal and urine samples were quantitatively collected over a 24 h period on d 40 and 82 of the study to evaluate serum and urinary content of DON and DON metabolites (iso-deoxynivalenol, DON-3-glucuronide, DON-15-glcurunide, deepoxy-deoxynivalenol, iso-deepoxy-deoxynivalenol, deepoxy-deoxynivalenol-3-glucuronide, and deepoxy-deoxynivalenol-15-glucuronide). The intake of DON was positively correlated with urinary DON output. Similarly, there was an increase in serum DON level with increasing DON intake. Overall, it was found that DON intake correlated with DON concentration in urine and blood serum when samples were collected under controlled conditions. Analyzing DON levels in urine and blood serum could be used to predict a pig's DON intake.

Combined Toxicity Evaluation of Ochratoxin A and Aflatoxin B1 on Kidney and Liver Injury, Immune Inflammation, and Gut Microbiota Alteration Through Pair-Feeding Pullet Model

Ochratoxin A (OTA) and aflatoxin B1 (AFB1) are often co-contaminated, but their synergistic toxicity in poultry is limitedly described. Furthermore, the traditional ad libitum feeding model may fail to distinguish the specific impact of mycotoxins on the biomarkers and the indirect effect of mildew on the palatability of feed. A pair-feeding model was introduced to investigate the specific effect and the indirect effect of the combined toxicity of OTA and AFB1, which were independent and dependent on feed intake, respectively. A total of 180 one-day-old pullets were randomly divided into 3 groups with 6 replicates, and each replicate contained 10 chicks. The control group (Group A) and the pair-feeding group (Group B) received the basal diet without mycotoxin contamination. Group C was administrated with OTA- and AFB1-contaminated feed (101.41 μg/kg of OTA + 20.10 μg/kg of AFB1). The scale of feeding in Group B matched with the feed intake of Group C. The trial lasted 42 days. Compared with the control group, co-contamination of OTA and AFB1 in feed could adversely affect the growth performance (average daily feed intake (ADFI), body weight (BW), average daily weight gain (ADG), feed conversion ratio (FCR), and shank length (SL)), decrease the relative weight of the spleen (p < 0.01), and increase the relative weight of the kidney (p < 0.01). Moreover, the reduction of feed intake could also adversely affect the growth performance (BW, ADG, and SL), but not as severely as mycotoxins do. Apart from that, OTA and AFB1 also activated the antioxidative and inflammation reactions of chicks, increasing the level of catalase (CAT), reactive oxygen species (ROS), and interleukin-8 (IL-8) while decreasing the level of IL-10 (p < 0.01), which was weakly influenced by the feed intake reduction. In addition, OTA and AFB1 induced histopathological changes and apoptosis in the kidney and liver as well as stimulated the growth of pernicious bacteria to cause toxic effects. There were no histopathological changes and apoptosis in the kidney and liver of the pair-feeding group. The combined toxicity of OTA and AFB1 had more severe effects on pullets than merely reducing feed supply. However, the proper reduction of the feed intake could improve pullets’ physical health by enriching the bacteria Lactobacillus, Phascolarctobacterium, Bacteroides, Parabacteroides, and Barnesiella.

The administration of diets contaminated with low to intermediate doses of deoxynivalenol and supplemented with antioxidants and binding agents slightly affects the growth, antioxidant status, and vaccine response in weanling pigs

This study aimed to evaluate the impact of grading levels of deoxynivalenol (DON) in the diet of weaned pigs, as well as the effects of a supplementation with antioxidants (AOX), hydrated sodium calcium aluminosilicates (HSCAS), and their combination on the growth, AOX status, and immune and vaccine responses against the porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). At weaning, 336 piglets were allocated to six dietary treatments according to a randomized complete block design. Treatments were as follows: basal diet (CTRL); basal diet containing DON at 1.2 mg/kg (DON1.2); basal diet containing DON at 2.4 mg/kg (DON2.4); DON2.4 diet + a mix of AOX which included vitamins A and E at 20,000 IU and 200 IU/kg feed respectively, selenized yeast at 0.3 mg/kg, and a grape seed extracts at 100 mg/kg feed (DON2.4 + AOX); DON2.4 diet + the mix of AOX and the modified HSCAS mentioned above (DON2.4 + AOX + HSCAS); DON2.4 + AOX + HSCAS. Pigs were vaccinated against PRRSV and PCV2 at 7 d; on 0, 14, and 35 d, growth performance was recorded, and blood samples were collected in order to evaluate the oxidative status, inflammatory blood markers, lymphocyte blastogenic response, and vaccine antibody response. Increasing intake of DON resulted in a quadratic effect at 35 d in the lymphocyte proliferative response to concanavalin A and PCV2 as well as in the anti-PRRSV antibody response, whereas the catalase activity decreased in DON2.4 pigs compared with the CTRL and DON1.2 groups (P ≤ 0.05). Compared with the DON2.4 diet, the AOX supplementation slightly reduced gain to feed ratio (P = 0.026) and increased the ferric reducing ability of plasma as well as α-tocopherol concentration (P < 0.05), whereas the association of AOX + HSCAS increased the anti-PRRSV IgG (P < 0.05). Furthermore, the HSCAS supplement reduced haptoglobin levels in serum at 14 d compared with the DON2.4 group; however, its concentration decreased in all the experimental treatments from 14 to 35 d and particularly in the DON2.4 + AOX pigs, whereas a different trend was evidenced in the DON2.4 + HSCAS group, where over the same period haptoglobin concentration increased (P < 0.05). Overall, our results show that the addition of AOX and HSCAS in the diet may alleviate the negative effects due to DON contamination on the AOX status and immune response of vaccinated weanling pigs.

Co-Occurrence of 35 Mycotoxins: A Seven-Year Survey of Corn Grain and Corn Silage in the United States

Mycotoxins contaminate crops worldwide and play a role in animal health and performance. Multiple mycotoxins may co-occur which may increase the impact on the animal. To assess the multiple mycotoxin profile of corn (Zea mays), we conducted a 7-year survey of new crop corn grain and silage in the United States. A total of 711 grain and 1117 silage samples were collected between 2013 and 2019 and analyzed for the simultaneous presence of 35 mycotoxins using ultra-performance liquid chromatography–tandem mass spectrometry. The measured mean number of mycotoxins per sample were 4.8 (grain) and 5.2 (silage), ranging from 0 to 13. Fusaric acid (FA) was most frequently detected in 78.1 and 93.8% of grains and silages, respectively, followed by deoxynivalenol (DON) in 75.7 and 88.2% of samples. Fumonisin B1 (FB1), fumonisin B2 and 15-acetyl-deoxynivalenol (15ADON) followed. The greatest (p < 0.05) co-occurrence was between FA and DON in 59.1% of grains and 82.7% of silages, followed by FA with FB1, DON with 15ADON, and FA with 15ADON. Although many samples had lower mycotoxin concentrations, 1.6% (grain) and 7.9% (silage) of tested samples had DON ≥ 5000 µg/kg. Fumonisins were detected ≥ 10,000 µg/kg in 9.6 and 3.9% of grain and silage samples, respectively. Concentrations in grain varied by year for eight mycotoxin groups (p < 0.05), while all 10 groups showed yearly variations in silage. Our survey suggest that multiple mycotoxins frequently co-occur in corn grain and silage in the United States, and some of the more prevalent mycotoxins are those that may not be routinely analyzed (i.e., FA and 15ADON). Assessment of multiple mycotoxins should be considered when developing management programs.

Phytobiotics with Adsorbent to Mitigate Toxicity of Multiple Mycotoxins on Health and Growth of Pigs

Phytobiotics with a mycotoxin adsorbent were used to mitigate negative effects of multiple mycotoxins in diets fed to pigs. In experiment 1, 120 pigs (11.6 kg body weight; BW) were assigned to five treatments (three pigs/pen) and fed for 28 days. Treatments were CON (control), MTD (CON + 2.5 mg/kg of deoxynivalenol), DP (MTD + phytobiotics at 0.1%), and DPA1 and DPA2 (MTD + phytobiotics and adsorbent at 0.1% and 0.2%, respectively). In experiment 2, 96 pigs (28.5 kg BW) were assigned to four treatments (three pigs/pen) and fed for 26 days. Treatments were CON, MTAF (CON + 0.19 mg/kg of aflatoxin and 8 mg/kg of fumonisins), AFP (MTAF + phytobiotics at 0.1%), and AFPA (MTAF + phytobiotics and adsorbent at 0.1%). Growth performance was measured weekly, and blood was sampled at the end of study to measure hepatic function and inflammatory status (TNF-α). Data were analyzed using the MIXED procedure. In experiment 1, pigs fed MTD, DP, DPA1, and DPA2 had smaller (p < 0.05) BW than CON. Pigs fed DPA2 had greater (p < 0.05) BW than MTD. Pigs fed DP and DPA2 tended to have lower (p < 0.1) serum total protein than CON. Pigs fed MTD and DPA2 tended to have higher (p < 0.1) alanine aminotransferase than CON. Similarly, pigs fed MTD, DP, and DPA2 tended to have higher (p < 0.1) urea nitrogen/creatinine than CON. In experiment 2, pigs fed MTAF, AFP, and AFPA had smaller (p < 0.05) BW than CON. Pigs fed MTAF, AFP, and AFPA had smaller (p < 0.05) ADFI than CON. Pigs fed AFPA had higher (p < 0.05) aspartate aminotransferase than CON and MTAF. Pigs fed AFP and AFPA had higher (p < 0.05) alanine aminotransferase than CON. Pigs fed MTAF, AFP, and AFPA had lower (p < 0.05) urea nitrogen/creatinine than CON. Pigs fed AFPA had higher (p < 0.05) TNF-α than CON and MTAF. In conclusion, feeding an additional 2.5 mg/kg of deoxynivalenol or 0.19 mg/kg of aflatoxin with 8 mg/kg of fumonisins reduced the growth of pigs. Deoxynivalenol compromised the hepatic function of pigs. Phytobiotics with adsorbent could partly overcome the detrimental effects of mycotoxins.