Deoxynivalenol (DON), a Fusarium mycotoxin frequently detected in poultry feeds, impairs broiler health by damaging gut integrity, altering immune response, and compromising growth performance. Insect-derived proteins, such as those from yellow mealworm (Tenebrio molitor) larvae meal (YMW), are gaining interest as an alternate protein source for broiler chickens. Hence, this study evaluated whether defatted YMW produced from larvae reared on DON-contaminated substrates can be safely included in broiler diets. A total of 400 one-day-old Cobb 700 mixed-sex broilers were assigned to four dietary treatments—(1) the control, (2) DON (15 mg/kg), (3) 2% YMW, and (4) 4% YMW—in ten replicates with 10 birds per replicate for 15 days. On day 14, performance parameters, intestinal morphology, tight-junction protein (TJP) gene expression, and CD4+ and CD8+ T-cell populations in cecal tonsils were evaluated. Data were analyzed using one-way ANOVA followed by Tukey’s multiple comparison test. DON exposure reduced body weight by 1% and body weight gain (BWG) by 1.2%, decreased the CD4+: CD8+ T-cell ratio by 80%, and reduced the villus height in the jejunum by 19.8% and ileum by 16%. DON altered the TJP expression by upregulating claudin-2 mRNA expression by 2.1-fold in the jejunum and 5.2-fold in the ileum, and it downregulated claudin-4 expression by 6.4-fold in the ileum (p < 0.05). Dietary inclusion of 2% or 4% YMW from DON-contaminated substrates had no negative effect on growth performance or immune parameters and maintained intestinal morphology and TJP gene expression, comparable to the control groups. In conclusion, defatted YMW produced from larvae reared on DON-contaminated substrates can be safely used as a sustainable alternative protein ingredient in broiler diets.

Sarocladium zeae is a protective fungal endophyte of maize with potential as a biological control agent because of its ability to suppress mycotoxin contamination through the production of secondary metabolites such as pyrrocidines. Here, we report high-quality genome assemblies for three S. zeae isolates, with assembly sizes ranging from 31.57 Mb to 31.74 Mb, N50 values from 3.73 Mb to 3.78 Mb, and BUSCO completeness scores of >98% and >95% against the fungi and Hypocreales databases, respectively. Comparative analysis revealed high genome-wide collinearity and sequence identity among the three isolates. Genome annotation predicted >9,600 protein-coding genes assigned to >7,200 protein families, along with 965 to 989 proteins with signal peptides, 2,225 to 2,259 transmembrane proteins, and 31 to 33 secondary metabolite biosynthetic gene clusters. These genomes expand the genomic resources available for S. zeae and will support future studies of the species’ genome evolution, secondary metabolism, and its interactions with maize and other microbes. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2026.

The mycotoxin deoxynivalenol (DON) contaminates chicken feed and negatively impacts intestinal health and overall production performance. The objective of this study was to investigate the effects of lactic acid bacteria and DON toxicity on production performance, intestinal morphology and absorptive function, and oxidative stress in broiler chickens. A total of 432 day-old-Ross 308 chicks were assigned to treatments arranged as a 2 × 3 factorial with mycotoxin (0 mg, noM; 5 mg/kg, M) and probiotic [0 cfu/kg, noP; 1.0 × 109 cfu/kg Lactobacillus acidophilus (LA); or 1.0 × 107 cfu/kg FloraMax-PW (FM), made of LA and Pediococcus acidilactici] and raised for 22 days. Body weight, average daily gain, average daily feed intake, and feed conversion ratio (FCR) were not affected (P = 0.130) by mycotoxin or mycotoxin × probiotic interaction for any days. However, FCR was reduced (P = 0.050) in FM compared to noP for days 8-15. Mycotoxin reduced villus height and villus height-to-crypt depth ratio (P = 0.029 and P = 0.027, respectively) in the jejunum. The level of jejunal zonula occludens-2 mRNA was reduced (P = 0.040) in M+noP and M+LA compared to noM+noP, noM+FM, noM+LA, and M+FM chickens. Ileal occludin and zonula occludens-2 mRNA expressions were increased (P < 0.001 and P = 0.011, respectively) by mycotoxin, and claudin-1 expression was increased (P = 0.029) by FM. Immunoglobulin A mRNA expression was increased (P = 0.020) in FM compared to noP while that of polymeric immunoglobulin receptor was increased (P = 0.004) in FM and LA in the ileum. Plasma catalase activity was reduced (P < 0.001) in M+noP compared to other treatments while that of glutathione reductase was increased (P = 0.036) by DON. In conclusion, DON at 5 mg/kg of feed did not affect production performance, but reduced intestinal morphology, which was not prevented by probiotics. The supplementation of FM improved the overall oxidative status in response to DON. In addition, FM improved intestinal immune genes expression in the context of this study.

Due to the critical nature of feed safety in poultry, safeguards are normally put in place to make sure that feed is safe for poultry. Mycotoxins are secondary metabolites that are produced by fungi which can, when consumed, result in issues including reduced appetite, suppressed growth, decreased feed efficiency, compromised immune systems, predisposition to secondary infections, poor production performance and mortality in poultry. Cocontamination of mycotoxins has been widely reported to exert negative synergistic effects as well. The objective of this study was to assess the prevalence and types of mycotoxin co-contamination levels in poultry feed and feed ingredients in the Southeastern U.S. Samples were analyzed for mycotoxin levels using HPLC-MS/MS and included corn (n = 335), soybeans (n = 60), soybean meal (n = 44), broiler feed (n = 64), and layer feed (n = 68). Out of the 572 tested samples, 86% were positive for fumonisin (FUM), 45% were positive for deoxynivalenol (DON), 36% were positive for zearalenone (ZEA), and 10% were positive for aflatoxin (AFLA). All corn and feed samples were contaminated with at least one mycotoxin. Results show that mycotoxin co-contamination seems to be very common, with 34% of the total samples contaminated with one mycotoxin, 25% with two mycotoxins, and 30% contaminated with three mycotoxins. The combination of DON + FUM made up the majority of the dual contaminations, and DON + FUM + ZEA made up the majority of the triple contaminations. Statistical differences were observed between concentrations of a given mycotoxin across different sample types. These data support the importance of routine testing for mycotoxins in finished feed and raw ingredients before providing them to poultry.

Fusarium verticillioides—a mycotoxigenic fungus and food safety threat—coinhabits maize kernels with Sarocladium zeae. This protective endophyte produces secondary metabolites of interest, pyrrocidines A and B, which inhibit the growth of F. verticillioides and specifically block fumonisin biosynthesis. Previous transcriptomic analyses found FvZBD1 (FVEG_00314), a gene adjacent to the fumonisin biosynthetic gene cluster, to be induced over 4,000-fold in response to pyrrocidine challenge. Deletion of FvZBD1 resulted in dramatic increases in fumonisin production (FB1 >30-fold). Here, using pyrrocidine dose-response assays, we discovered a potent synergy between pyrrocidines A and B, where they functioned powerfully together to inhibit F. verticillioides growth. Further, results provided evidence that FvZBD1 confers partial tolerance to pyrrocidines, particularly pyrrocidine A, and that pyrrocidine functions through FvZBD1 to effectively eliminate fumonisin biosynthesis. Additionally, we showed that the FvABC3 (FVEG_11089) mutant, earlier described as hypersensitive to pyrrocidine, is particularly sensitive to pyrrocidine B. Thus, pyrrocidine A and B show different target specificity (FvZBD1 or FvABC3) and synergistic action. These findings will help inform the optimization of maximally efficacious S. zeae strains for eliminating F. verticillioides colonization and fumonisin contamination in maize cropping systems. This novel study contributes significantly to our knowledge of competitive microorganism relationships and the role of secondary metabolites in antagonistic fungal-fungal interactions.

Identifying biomarkers of mycotoxin effects in chickens will provide an opportunity for early intervention to reduce the impact of mycotoxicosis. This study aimed to identify whether serum enzyme concentrations, gut integrity, and liver miRNAs can be potential biomarkers for fumonisin B1 (FB1), deoxynivalenol (DON), and zearalenone (ZEA) toxicity in broiler birds as early as 14 days after exposure. A total of 720 male broiler chicks were distributed to six treatment groups: T1: control group (basal diet), T2 (2 FB1 + 2.5 DON + 0.9 ZEA), T3 (5 FB1 + 0.4 DON + 0.1 ZEA), T4 (9 FB1 + 3.5 DON + 0.7 ZEA), T5 (17 FB1 + 1.0 DON + 0.2 ZEA), and T6 (21 FB1 + 3.0 DON + 1.0 ZEA), all in mg/kg diet. On d14, there were no significant differences in the body weight gain (BWG) of mycotoxin treatment groups when compared to the control (p > 0.05), whereas on d21, T6 birds showed significantly reduced BWG compared to the control (p < 0.05). On d14, birds in T6 showed significant upregulation of liver miRNAs, gga-let-7a-5p (14.17-fold), gga-miR-9-5p (7.05-fold), gga-miR-217-5p (16.87-fold), gga-miR-133a-3p (7.41-fold), and gga-miR-215-5p (6.93-fold) (p < 0.05) and elevated serum fluorescein isothiocyanate-dextran (FITC-d) concentrations, aspartate aminotransferase (AST), and creatine kinase (CK) levels compared to the control (p < 0.05). On d21, T2 to T6 birds exhibited reduced serum phosphorus, glucose, and potassium, while total protein, FITC-d, AST, and CK levels increased compared to control (p < 0.05). These findings suggest that serum FITC-d, AST, CK, and liver miRNAs could serve as biomarkers for detecting mycotoxin exposure in broiler chickens.

The mycotoxigenic fungi, Aspergillus flavus and Fusarium verticillioides, commonly co-colonize maize in the field, yet their direct interactions at the chemical communication level have not been well characterized. Here, we examined if and how the two most infamous mycotoxins produced by these species, aflatoxin and fumonisin, respectively, govern interspecies growth and mycotoxin production. We showed that fumonisin producing strains of F. verticillioides suppressed the growth of A. flavus while non-producers did not. Additionally, while aflatoxin did not inhibit F. verticillioides growth, it did suppress fumonisin production. Fumonisin B1 concentration levels plummeted when challenged with a high dose of aflatoxin B1 or with an aflatoxin producing strain. With these findings, expression of the genetic regulators of secondary metabolism was investigated for both fungi. While no strong effect was seen on genes in the aflatoxin biosynthetic gene cluster when exposed to fumonisin B1, the fumonisin repressor FvZBD1, which is adjacent to the cluster, was induced with expression proportionate to concentration when F. verticillioides was challenged with aflatoxin B1. We also assessed the expression of the global regulators of fungal secondary metabolism, veA and laeA, and found that their expression is altered in both A. flavus and F. verticillioides when exposed to their competitor’s mycotoxin. This work gives insight into the ecological roles of mycotoxins and why these fungi may produce them as weapons in the interspecies battle for resource acquisition.

During poultry meat processing, multiple biocides can be applied to reduce foodborne pathogen contamination. Previous experiments have investigated the efficacy of several biocides, but few have investigated the efficacy of multiple biocides applied in series. Here, we evaluated the synergistic effects of peracetic acid (PAA) in combination with other commonly applied biocides approved for use in U.S. poultry meat processing: cetylpyridinium chloride (CPC), calcium hypochlorite (CH), and sodium hypochlorite (SH). Serotype-specific mixtures of Salmonella isolates (serotypes Typhimurium, Enteritidis, Kentucky, and Infantis) were exposed to PAA and other biocides, individually and in combination, in 96-well plates using broth culture. Mixtures were exposed to the first biocide for 15 s, the second biocide for 15 s, and chemical activity was then neutralized with Dey-Engley broth, and cultures were incubated overnight to determine recoverability via pH indicator. Across three trials, results were highly variable for all serotypes and combinations tested; however, responses to non-PAA biocides were uniform when applied individually. When applied in combination, order of application significantly impacted PAA tolerance (pd < 0.05). Application of any non-zero concentration of CH or SH also resulted in significantly lower PAA tolerance across all serotypes (pd < 0.05). Dilution could not be ruled out as the cause of the tolerance or the variability. Variable results highlight the need to test biocides on meat products to accurately evaluate efficacy for poultry meat processing. IMPORTANCE:Salmonella enterica is one of the most common causes of human foodborne illness attributed to consumption of contaminated poultry in the U.S. Because many different biocide antimicrobials are used in serial during poultry processing, we investigated the tolerance of four serotypes of non-typhoidal Salmonella to four biocides applied in serial. Although responses were variable, we concluded that any non-zero concentration of calcium or sodium hypochlorite applied before peracetic acid will decrease the PAA tolerance of all four serotypes. These data are primarily useful in planning applied studies of biocides on meat products for disinfection.

Nitrous oxide (N2O) derived from agricultural activity is a major contributor to Earth's greenhouse effect. Synthetic nitrogen fertilizer applied at high levels, particularly combined with heavy rainfall events, generates hot spots of N2O emissions in agricultural fields due to the process of microbial denitrification. Here, a key conserved fungal denitrification enzyme necessary for N2O emissions was identified. Phylogenetic analysis revealed that fungal NOR1-like genes, with rare exceptions, are highly conserved and confined to the phylum Ascomycota. Plant pathogenic Fusarium species that possess NOR1 exhibited drastic differences in N2O production based on denitrification potential. Functional characterization of the p450nor nitric oxide reductase encoding gene, NOR1, in the soil-borne denitrifying maize pathogen, Fusarium verticillioides, showed that this enzyme is critical for fungal N2O production. Deletion of the single copy NOR1 gene in F. verticillioides eliminated N2O emissions. Complementation of deletion mutants via the NOR1 gene add-back restored wild type N2O emission levels and segregation analysis further corroborated the pivotal role of NOR1 for N2O emissions. We suggest targeting of the NOR1 enzyme as an effective strategy to reduce fungal-based N2O emissions.

Fusarium mycotoxins often co-occur in broiler feed, and their presence negatively impacts health even at subclinical concentrations, so there is a need to identify the concentrations of these toxins that do not adversely affect chickens health and performance. The study was conducted to evaluate the least toxic effects of combined mycotoxins fumonisins (FUM), deoxynivalenol (DON), and zearalenone (ZEA) on the production performance, immune response, intestinal morphology, and nutrient digestibility of broiler chickens. A total of 960 one-day-old broilers were distributed into eight dietary treatments: T1 (Control); T2: 33.0 FUM + 3.0 DON + 0.8 ZEA; T3: 14.0 FUM + 3.5 DON + 0.7 ZEA; T4: 26.0 FUM + 1.0 DON + 0.2 ZEA; T5: 7.7 FUM + 0.4 DON + 0.1 ZEA; T6: 3.6 FUM + 2.5 DON + 0.9 ZEA; T7: 0.8 FUM + 1.0 DON + 0.3 ZEA; T8: 1.0 FUM + 0.5 DON + 0.1 ZEA, all in mg/kg diet. The results showed that exposure to higher mycotoxin concentrations, T2 and T3, had significantly reduced body weight gain (BWG) by 17% on d35 (p < 0.05). The T2, T3, and T4 groups had a significant decrease in villi length in the jejunum and ileum (p < 0.05) and disruption of tight junction proteins, occludin, and claudin-4 (p < 0.05). Higher mycotoxin groups T2 to T6 had a reduction in the digestibility of amino acids methionine (p < 0.05), aspartate (p < 0.05), and serine (p < 0.05); a reduction in CD4+, CD8+ T-cell populations (p < 0.05) and an increase in T regulatory cell percentages in the spleen (p < 0.05); a decrease in splenic macrophage nitric oxide production and total IgA production (p < 0.05); and upregulated cytochrome P450-1A1 and 1A4 gene expression (p < 0.05). Birds fed the lower mycotoxin concentration groups, T7 and T8, did not have a significant effect on performance, intestinal health, and immune responses, suggesting that these concentrations pose the least negative effects in broiler chickens. These findings are essential for developing acceptable thresholds for combined mycotoxin exposure and efficient feed management strategies to improve broiler performance.

Mycotoxin contaminated corn poses a risk to poultry production. Although mycotoxin regulatory guidelines are based on the hazards of individual mycotoxin contamination, feed and feed ingredients may be contaminated with multiple mycotoxins. The objective of this study was to assess mycotoxin co-contamination and its impact on the nutrient content of corn grain. Corn samples (n = 328) originating from various regions in the Southeastern U.S. were quantitatively analyzed for fumonisin (FUM), deoxynivalenol (DON), aflatoxin (AFB1) and zearalenone (ZEA) by HPLC-MS/MS. Nutritional content was analyzed by near-infrared spectroscopy, and color data were collected. All 328 samples were found to be contaminated with at least 1 mycotoxin: 100% contained FUM (19-24,680 µg/kg), 69.82% contained DON (0-9,640 µg/kg), 17.07% contained AFB1 (0-939 µg/kg), and 43.60% had detectable levels of ZEA (0-8,093.5 µg/kg). Most of the samples were contaminated with 2 or more mycotoxins, with only 18.29% of the samples containing a single mycotoxin. 38.41% of the samples had 2 mycotoxins present, 36.59 % had 3 mycotoxins, and 4.88% of the samples had all 4 tested mycotoxins present. Samples contaminated with AFB1 had significantly lower fat (P = 0.007) and lightness (P = 0.007); samples contaminated with DON had significantly higher starch (P < 0.001) and lower protein (P < 0.001). Samples contaminated with FUM had significantly higher protein (P = 0.008) and moisture (P = 0.019) and lower starch (P < 0.001). ZEA contaminated samples had significantly lower starch (P = 0.034). A correlation was observed between mycotoxin contamination and altered nutrient content in corn. This study provides further evidence that co-contamination of mycotoxins is the norm in corn, and that mycotoxin contamination correlates with impacts on the nutrient profile of feed corn.

Salmonella is a common cause of human foodborne illness, which is frequently associated with consumption of contaminated or undercooked poultry meat. Serotype Infantis is among the most common serotypes isolated from poultry meat products globally. Isolates of serotype Infantis carrying the pESI plasmid, the most dominant strain of Infantis, have been shown to exhibit oxidizer tolerance. Therefore, 16 strains of Salmonella with and without pESI carriage were investigated for susceptibility to biocide chemical processing aids approved for use in US poultry meat processing: peracetic acid (PAA), cetylpyridinium chloride (CPC), calcium hypochlorite, and sodium hypochlorite. Strains were exposed for 15 s to simulate spray application and 90 min to simulate application in an immersion chiller. All strains tested were susceptible to all concentrations of PAA, CPC, and sodium hypochlorite when applied for 90 min. When CPC, calcium hypochlorite, and sodium hypochlorite were applied for 15 s to simulate spray time, strains responded similarly to each other. However, strains responded variably to exposure to PAA. The variation was not statistically significant and appears unrelated to pESI carriage. Results highlight the necessity of testing biocide susceptibility in the presence of organic material and in relevant in situ applications.

Aspergillus flavus and its toxic metabolites-aflatoxins infect and contaminate maize kernels, posing a threat to grain safety and human health. Due to the complexity of microbial growth and metabolic processes, dynamic mechanisms among fungal growth, nutrient depletion of maize kernels and aflatoxin production is still unclear. In this study, visible/near infrared (Vis/NIR) hyperspectral imaging (HSI) combined with the scanning electron microscope (SEM) was used to elucidate the critical organismal interaction at kernel (macro-) and microscopic levels. As kernel damage is the main entrance for fungal invasion, maize kernels with gradually aggravated damages from intact to pierced to halved kernels with A. flavus were cultured for 0-120 h. The spectral fingerprints of the A. flavus-maize kernel complex over time were analyzed with principal components analysis (PCA) of hyperspectral images, where the pseudo-color score maps and the loading plots of the first three PCs were used to investigate the dynamic process of fungal infection and to capture the subtle changes in the complex with different hardness of the maize matrix. The dynamic growth process of A. flavus and the interactions of fungus-maize complexes were explained on a microscopic level using SEM. Specifically, fungus morphology, e.g., hyphae, conidia, and conidiophore (stipe) was accurately captured on the microscopic level, and the interaction process between A. flavus and nutrient loss from the maize kernel tissues (i.e., embryo, and endosperm) was described. Furthermore, the growth stage discrimination models based on PLSDA with the results of CCRC = 100 %, CCRV = 97 %, CCRIV = 93 %, and the prediction models of AFB1 based on PLSR with satisfactory performance (R2C = 0.96, R2V = 0.95, R2IV = 0.93 and RPD = 3.58) were both achieved. In conclusion, the results from both macro-level (Vis/NIR-HSI) and micro-level (SEM) assessments revealed the dynamic organismal interactions in A. flavus-maize kernel complex, and the detailed data could be used for modeling, and quantitative prediction of aflatoxin, which would establish a theoretical foundation for the early detection of fungal or toxin contaminated grains to ensure food security.

Organic acids and essential oils are commonly used in the poultry industry as antimicrobials and for their beneficial effects on gut health, growth performance, and meat quality. A common postharvest storage fungal colonist, Aspergillus flavus, contaminates corn, the primary component of poultry feed, with the highly detrimental mycotoxin, aflatoxin. Aflatoxin adversely affects poultry feed intake, feed conversion efficiency, weight gain, egg production, fertility, hatchability, and poultry meat yield. Both organic acids and essential oils have been reported to inhibit the growth of A. flavus. Thus, we evaluated if the inhibitory synergy between combined essential oils (cinnamon, lemongrass, and oregano) and organic acids (acetic, butyric, and propionic) prevents A. flavus growth. The study confirmed that these compounds inhibit the growth of A. flavus and that synergistic interactions do occur between some of them. Overall, cinnamon oil was shown to have the highest synergy with all the organic acids tested, requiring 1000 µL/L air of cinnamon oil and 888 mg/kg of butyric acid to fully suppress A. flavus growth on corn kernels. With the strong synergism demonstrated, combining certain essential oils and organic acids offers a potentially effective natural method for controlling postharvest aflatoxin contamination in poultry feed.

Fusarium endophytes damage cereal crops and contaminate produce with mycotoxins. Those fungi overcome the main chemical defence of host via detoxification by a malonyl-CoA-dependent enzyme homologous to xenobiotic metabolizing arylamine N-acetyltransferase (NAT). In Fusarium verticillioides (teleomorph Gibberella moniliformis, GIBMO), this N-malonyltransferase activity is attributed to (GIBMO)NAT1, and the fungus has two additional isoenzymes, (GIBMO)NAT3 (N-acetyltransferase) and (GIBMO)NAT2 (unknown function). We present the crystallographic structure of (GIBMO)NAT1, also modelling other fungal NAT homologues. Monomeric (GIBMO)NAT1 is distinctive, with access to the catalytic core through two "tunnel-like" entries separated by a "bridge-like" helix. In the quaternary arrangement, (GIBMO)NAT1 monomers interact in pairs along an extensive interface whereby one entry of each monomer is covered by the N-terminus of the other monomer. Although monomeric (GIBMO)NAT1 apparently accommodates acetyl-CoA better than malonyl-CoA, dimerization changes the active site to allow malonyl-CoA to reach the catalytic triad (Cys110, His158 and Asp173) via the single uncovered entry, and anchor its terminal carboxyl-group via hydrogen bonds to Arg109, Asn157 and Thr261. Lacking a terminal carboxyl-group, acetyl-CoA cannot form such stabilizing interactions, while longer acyl-CoAs enter the active site but cannot reach catalytic Cys. Other NAT isoenzymes lack such structural features, with (GIBMO)NAT3 resembling bacterial NATs and (GIBMO)NAT2 adopting a structure intermediate between (GIBMO)NAT1 and (GIBMO)NAT3. Biochemical assays confirmed differential donor substrate preference of (GIBMO)NAT isoenzymes, with phylogenetic analysis demonstrating evolutionary separation. Given the role of (GIBMO)NAT1 in enhancing Fusarium pathogenicity, unravelling the structure and function of this enzyme may benefit research into more targeted strategies for pathogen control.

Fusarium verticillioides is a mycotoxigenic fungus that is a threat to food and feed safety due to its common infection of maize, a global staple crop. A proposed strategy to combat this threat is the use of biological control bacteria that can inhibit the fungus and reduce mycotoxin contamination. In this study, the effect of multiple environmental isolates of Streptomyces on F. verticillioides was examined via transcriptome analysis. The Streptomyces strains ranged from inducing no visible response to dramatic growth inhibition. Transcriptionally, F. verticillioides responded proportionally to strain inhibition with either little to no transcript changes to thousands of genes being differentially expressed. Expression changes in multiple F. verticillioides putative secondary metabolite gene clusters was observed. Interestingly, genes involved in the fusaric acid gene cluster were suppressed by inhibitory strains of Streptomyces. A F. verticillioides beta-lactamase encoding gene (FVEG_13172) was found to be highly induced by specific inhibitory Streptomyces strains and its deletion increased visible response to those strains. This study demonstrates that F. verticillioides does not have an all or nothing response to bacteria it encounters but rather a measured response that is strain specific and proportional to the strength of inhibition.

Semicarbazide (SEM) is routinely employed as an indicator for the use of nitrofurazone, a banned antimicrobial. The validity of SEM as a nitrofurazone marker has been scrutinized because of other possible sources of the compound. Nonetheless, a U.S. trade partner rejected skin-on chicken thighs because of SEM detection and suspected nitrofurazone use. Because nitrofurazone has been banned in U.S. broiler production since 2003, we hypothesized that incidental de novo SEM formation occurs during broiler processing. To assess this possibility, raw leg quarters were collected from 23 conunercial broiler processing plants across the United States and shipped frozen to our laboratory, where liquid chromatography-mass spectrometry was used to quantitatively assess for SEM. Leg quarter samples were collected at four points along the processing line: hot rehang (transfer from the kill line to the evisceration line), prechill (before the chilling process), postchill (immediately following chilling), and at the point of pack. Thigh meat with skin attached was removed from 535 leg quarters and analyzed in triplicate for SEM concentrations. The concentrations ranged from 0 to 2.67 ppb, with 462 (86.4%) of 535 samples below the regulatory decision level of 0.5 ppb of SEM. The 73 samples over the 0.5-ppb limit came from 21 plants; 53 (72.6%) of positive samples were in meat collected after chilling (postchill or point of pack). The difference in both prevalence and concentration of SEM detected before and after chilling was highly significant (P < 0.0001). These data support our hypothesis that SEM detection in raw broiler meat is related to de novo creation of the chemical during processing.

Fumonisins (FB) and deoxynivalenol (DON) are mycotoxins which may predispose broiler chickens to necrotic enteritis (NE). The objective of this study was to identify the effects of subclinical doses of combined FB and DON on NE. A total of 480 day-old male broiler chicks were divided into four treatment groups; 1) control group (basal diet + Clostridium perfringens); 2) necrotic enteritis group (basal diet + Eimeria maxima + C. perfringens); 3) FB + DON group (basal diet + 3 mg/kg FB + 4 mg/kg DON + C. perfringens); and 4) FB + DON + NE group (basal diet + 3 mg/kg FB + 4 mg/kg DON + E. maxima + C. perfringens). Birds in NE and FB + DON + NE groups received 2.5 × 103E. maxima on day 14. All birds were inoculated with C. perfringens on days 19, 20, and 21. On day 35, birds in the NE, FB + DON, and FB + DON + NE groups had 242, 84, and 339 g lower BWG and a 19-, 2-, and 22-point increase in FCR respectively, than in the control group. Subclinical doses of FB + DON increased (p < 0.05) the NE lesion scores compared to the control group on day 21. On day 21, birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) serum FITC-D, lower (p < 0.05) jejunal tight junction protein mRNA, and increased (p < 0.05) cecal tonsil IL-1 mRNA compared to control group. On day 21, birds in the NE group had decreased (p < 0.05) villi height to crypt depth ratio compared to the control group and the presence of FB + DON in NE-induced birds further decreased the villi height to crypt depth ratio. Birds in the NE, FB + DON, and FB + DON + NE groups had increased (p < 0.05) C. perfringens, lower (p < 0.05) Lactobacillus loads in the cecal content, and a lower (p < 0.05) CD8+: CD4+ cell ratio in the cecal tonsils compared to the control group. It can be concluded that subclinical doses of combined FB and DON predispose C. perfringens-inoculated birds to NE, and the presence of FB + DON in NE-induced birds exacerbated the severity of NE.

The dynamics mechanisms regulating the growth and AFB1 production of Aspergillus flavus during its interactions with maize kernels remain unclear. In this study, shortwave infrared hyperspectral imaging (SWIR-HSI) and synchrotron radiation Fourier transform infrared (SR-FTIR) microspectroscopy were combined to investigate chemical and spatial-temporal changes in incremental damaged maize kernels induced by A. flavus infection at macroscopic and microscopic levels. SWIR-HSI was employed to extract spectral information of A. flavus growth and quantitatively detect AFB1 levels. Satisfactory full-spectrum models and simplified multispectral models were obtained respectively by partial least squares regression (PLSR) for three types of samples. Furthermore, SR-FTIR microspectroscopy coupled with two-dimensional correlation spectroscopy (2DCOS) was utilized to reveal the possible sequence of dynamic changes of nutrient loss and trace AFB1 in maize kernels. It exhibited new insights on how to quantify the spatio-temporal patterns of fungal infection and AFB1 accumulation on maize and provided theoretical basis for online sorting.