Multiannual mycotoxin survey in feed materials and feedingstuffs

Low Doses of Mycotoxin Mixtures below EU Regulatory Limits Can Negatively Affect the Performance of Broiler Chickens: A Longitudinal Study

Several studies have reported a wide range of severe health effects as well as clinical signs, when livestock animals are exposed to high concentration of mycotoxins. However, little is known regarding health effects of mycotoxins at low levels. Thus, a long-term feeding trial (between May 2017 and December 2019) was used to evaluate the effect of low doses of mycotoxin mixtures on performance of broiler chickens fed a naturally contaminated diet. In total, 18 successive broiler performance trials were carried out during the study period, with approximately 2200 one-day-old Ross-308 chicks used for each trial. Feed samples given to birds were collected at the beginning of each trial and analysed for multi-mycotoxins using a validated LC-MS/MS method. Furthermore, parameters including feed intake, body weight and feed efficiency were recorded on a weekly basis. In total, 24 mycotoxins were detected in samples analysed with deoxynivalenol (DON), zearalenone (ZEN), fumonisins (FBs), apicidin, enniatins (ENNs), emodin and beauvericin (BEV), the most prevalent mycotoxins. Furthermore, significantly higher levels (however below EU guidance values) of DON, ZEN, FBs, BEV, ENNs and diacetoxyscirpenol (DAS) were detected in 6 of the 18 performance trials. A strong positive relationship was observed between broilers feed efficiency and DON (R2 = 0.85), FBs (R2 = 0.53), DAS (R2 = 0.86), ZEN (R2 = 0.92), ENNs (R2 = 0.60) and BEV (R2 = 0.73). Moreover, a three-way interaction regression model revealed that mixtures of ZEN, DON and FBs (p = 0.01, R2 = 0.84) and ZEN, DON and DAS (p = 0.001, R2 = 0.91) had a statistically significant interaction effect on the birds' feed efficiency. As farm animals are often exposed to low doses of mycotoxin mixtures (especially fusarium mycotoxins), a cumulative risk assessment in terms of measuring and mitigating against the economic, welfare and health impacts is needed for this group of compounds.

Mycotoxin Determination in Animal Feed: An LC-FLD Method for Simultaneous Quantification of Aflatoxins, Ochratoxins and Zearelanone in This Matrix

Mycotoxins are toxic compounds for humans and animals that are produced by fungi. Mycotoxin contamination in feed is a global safety concern and effective control of these compounds in this matrix is needed. This study proposes a simple, cost-effective analytical method based on liquid chromatography coupled with a fluorescence detector, which is suitable for the routine monitoring of some of the most important mycotoxins in feed: aflatoxins (G2, G1, B2, and B1), zearalenone, and ochratoxins A and B. Mycotoxin extraction, chromatographic separation and quantification are carried out simultaneously for all mycotoxins. The extraction procedure is performed using acetonitrile, water and orthophosphoric acid (80:19:1). Purification of the extract is carried out using an OASIS PRIME HLB solid-phase extraction cartridge followed by a dispersive liquid-liquid microextraction procedure. Aflatoxins G1 and B1 are derivatized post-column (photochemical reactor at 254 nm) to increase their signal. The method has been validated in feed for pigs, cows, sheep, and poultry with very satisfactory results. The detection limits are 2 μg/kg for aflatoxins B1 and G1, 0.64 μg/kg for aflatoxins B2 and G2, 42 μg/kg for zearalenone, and 5 μg/kg for ochratoxins A and B. These values are low enough to allow for monitoring of these mycotoxins in feed. Global recovery values were between 73.6% and 88.0% for all toxins with a relative standard deviation (RSD) % < 7%. This methodology will facilitate laboratory control and analysis of mycotoxins in feed.

Mycotoxins, invisible danger of feedstuff with toxic effect on animals

Mycotoxins are low-molecular weight compounds produced mainly by fungi, with Fusarium and Aspergillus origin. Secondary, metabolites, are mostly found on plants. However, the contamination of the feed and forage has been also reported. Because of their pharmacological activity, mycotoxins can be used as chemical warfare agents, drugs or growth promotants. Additionally, mycotoxins are found as one of the most dangerous genotoxic factors which cause the damage of DNA and lead to disease development. This review includes the knowledge of mycotoxins as both, an invisible danger of forage and as food additives. Special emphasis shall be given on mycotoxins with proven cancerogenic activity; including aflatoxins, fumonisins, ochratoxins, trichothecenes, and zearalenone. Factors such as species, mechanisms/modes of action, metabolism, and defense mechanisms were taken into account. The main concern was focused on zearalenone characterization, because of its estrogenic activity, caused by structural similarity to estrogens, naturally occurring in cells. By binding to estrogenic receptors, toxins are, accumulated in organisms and long-term exposure may cause the disturbances, especially in the reproductive system. The next part of this paper contains the description of main strategies of toxins determination. Finally, in the review, several potential methods for the dioxins neutralization were discussed.

Compound probiotics alleviating aflatoxin B1 and zearalenone toxic effects on broiler production performance and gut microbiota

In order to alleviate toxic effects of aflatoxins B₁ (AFB₁) and zearalenone (ZEA) on broiler production performance and gut microbiota, three kinds of compound probiotics (CP) were selected. The optimal ratios of Bacillus subtilis, Lactobacillus casei and Candida utilis in broiler diets were 7, 5 and 6 log CFU/g for ZEA biodegradation (CP1); 6, 7 and 7 log CFU/g for AFB₁ biodegradation (CP2); 7, 6 and 7 log CFU/g for ZEA + AFB₁ biodegradation (CP3). A total of 350 1-day-old Ross broilers were randomly divided into 7 groups. Group A was the basal diet, group B-G contained ZEA, AFB₁, ZEA + AFB₁, ZEA + CP1, AFB₁+CP2, ZEA + AFB₁+CP3, respectively. The experiment showed that AFB₁ or AFB₁+ZEA significantly decreased broiler production performance, damaged liver and jejunum, increased mycotoxin residues in broiler body; however, three kinds of compound probiotics additions could alleviate mycotoxin negative effects on the above parameters (p < 0.05). The gut microbiota analysis indicated that AFB₁+ZEA increased jejunal microbial richness, but which were decreased to almost the same level as the control group by CP3 addition. CP3 addition significantly increased jejunal Firmicutes and Lactobacillus aviarius abundances. The correlative analysis showed that gut Lactobacillus aviarius abundance was positively correlated with average daily gain (ADG) of broilers (p < 0.05), while AFB₁+ZEA addition decreased its relative abundance, indicating that CP3 addition increased broiler growth by increasing Lactobacillus aviarius abundance. AFB₁ and ZEA residues in broiler body were negatively correlated with the gut beneficial bacterial abundances (p < 0.01), but positively correlated with the potentially harmful bacterial abundances (p < 0.05), which inferred that CP3 addition could decrease mycotoxin residues through positively regulating gut relative bacterial abundances. In conclusion, compound probiotics could keep gut microbiota stable, degrade mycotoxins, alleviate histological lesions, increase production performance and reduce mycotoxin toxicity for broilers.

Occurrence of on-farm risk factors and health effects of mycotoxins in dairy farms in Jordan

The aim of this study was to determine the occurrence of on-farm risk factors and health effects associated with contamination of dairy feeds with aflatoxins (AFs), zearalenone (ZEN), trichothecenes (T-2), deoxynivalenol (DON), and fumonisins (FB) in Jordan. A pre-tested and validated questionnaire was used to determine on-farm practices and health effects associated with high levels of mycotoxins. A total of 88 feed samples were collected from the 37 farms participating in the study and analyzed using commercially available ELISA kits. The mean total AF concentration exceeded the European Union (EU) limit in alfalfa (4%) and total mixed ration (TMR) (3%) samples. Similarly, levels exceeding EU limits were observed for T-2 in alfalfa (29%), TMR (30%), and corn silage (4%). The average concentrations of ZEN and FB were 300 ppb and 11,638 ppb, respectively, which were below the EU maximum limits in all feed samples examined. Intensive management system (OR = 7.70), imported feed (OR = 3.40), feed storage on the farm for more than 1-month duration (OR = 7.90), and not using antitoxins (OR = 2.30) were significantly (P < 0.05) associated with high levels of mycotoxins in feed samples. A significant correlation (P < 0.05) was evident between the presence of mycotoxins in dairy feed and feed refusal (R = 0.70), low milk production (R = 0.50), diarrhea problems (R = 0.60), infertility (R = 0.50), and repeated breeder problems (R = 0.80). Results show that mycotoxin contamination in dairy feeds is a problem in Jordan, and appropriate measures need to be undertaken to reduce risks to human and animal health and improve production.

Sources, quantification techniques, associated hazards, and control measures of mycotoxin contamination of aquafeed

With the productive intensification of fish farming, the partial or total replacement of fishmeal by ingredients of plant origin became a reality within the feed industry, with the aim of reducing costs. However, this practice increased the impact of mycotoxin contamination. Studies have shown that mycotoxins can induce various disorders in fish, such as cellular and organic alterations, as well as impair functional and morphological development, and, in more severe cases, mortality. Thus, studies have been conducted to evaluate and develop strategies to prevent the formation of mycotoxins, as well as to induce their elimination, inactivation or reduction of their availability in feed.

Potential adverse effects on animal health and performance caused by the addition of mineral adsorbents to feeds to reduce mycotoxin exposure

The contamination of feed with mycotoxins is a continuing feed quality and safety issue, leading to significant losses in livestock production and potential human health risks. Consequently, various methods have been developed to reduce the occurrence of mycotoxins in feed; however, feed supplementation with clay minerals or mineral adsorbents is the most prominent approach widely practiced by farmers and the feed industry. Due to a negatively charged and high surface area, pore volume, swelling ability, and high cation exchange capacity, mineral adsorbents including bentonite, zeolite, montmorillonite, and hydrated sodium calcium aluminosilicate can bind or adsorb mycotoxins to their interlayer spaces, external surface, and edges. Several studies have shown these substances to be partly or fully effective in counteracting toxic effects of mycotoxins in farm animals fed contaminated diets and thus are extensively used in livestock production to reduce the risk of mycotoxin exposure. Nevertheless, a considerable number of studies have indicated that these agents may also cause undesirable effects in farm animals. The current work aims to review published reports regarding adverse effects that may arise in farm animals (with a focus on pig and poultry) and potential interaction with veterinary substances and nutrients in feeds, when mineral adsorbents are utilized as a technological feed additive. Furthermore, results of in vitro toxicity studies of both natural and modified mineral adsorbents on different cell lines are reported. Supplementation of mycotoxin-contaminated feed with mineral adsorbents must be carefully considered by farmers and feed industry.

Mycotoxins feed contamination in a dairy farm - potential implications for milk contamination and workers' exposure in a One Health approach

BACKGROUND

Dairy farming feed can be contaminated with mycotoxins, affecting animals' health and milk quality. Dairy farming is also prone to occupational exposure to mycotoxins, and feed is recognized as a source of contamination in the workplace. An exploratory study was developed in a dairy farm located in Portugal intending to assess the mycotoxins present in the feed.

RESULTS

All the samples analyzed presented contamination by at least two mycotoxins and up to a maximum of 13 mycotoxins in the same sample. Zearalenone (ZEA) was detected in all the samples (n = 10) followed by deoxynivalenol (DON), which was reported in eight samples, and ochratoxin A (OTA), reported in five samples.

CONCLUSION

The results point to the possible contamination of milk by several mycotoxins and raise the possibility of occupational exposure to mycotoxins due to feed contamination. An adequate One Health approach for dairy production should address these issues through effective preventive actions such as avoiding the use of feed contaminated with mycotoxins. This represents an important challenge due to climate change. It requires proper attention and accurate management measures. © 2019 Society of Chemical Industry.

The protective effects of modified palygorskite on the broilers fed a purified zearalenone-contaminated diet

This study was conducted to evaluate the protective effects of dietary modified palygorskite (Pal) supplementation on broiler chickens fed a purified zearalenone (ZEN)-contaminated diet. A total of 144 1-day-old male chicks were allocated to one of the 3 treatments, with each treatment being composed of 6 replicates of 8 birds each. The birds were fed with a control diet (Control group), the ZEN-contaminated diet (2.0 mg ZEN/kg diet), and the ZEN-contaminated diet supplemented with 1.0 g/kg diet of modified Pal for 42 d, respectively. Compared with control group, feeding ZEN-contaminated diet reduced weight gain and feed conversion efficiency of broilers during the finisher and overall experimental period (P < 0.05), while the values of these parameters in broilers fed the diet contaminated with ZEN increased after modified Pal administration (P < 0.05). ZEN challenge increased the 21-d serum aspartate aminotransferase and 42-d serum alanine aminotransferase activities, 42-d relative liver weight, and ZEN residues in the liver at both 21 and 42 d and kidney at 42 d (P < 0.05). In contrast, birds fed the ZEN-contaminated diet that was supplemented with modified Pal exhibited lower serum alanine aminotransferase activity at 42 d, relative liver weight at 42 d, and hepatic and renal ZEN accumulation at both 21 and 42 d (P < 0.05), when compared with their counterparts fed the contaminated diet. ZEN contamination decreased superoxide dismutase activity in the serum at 21 d, kidney at 42 d, and liver at both 21 and 42 d, respectively (P < 0.05). The hepatic and renal malondialdehyde accumulation at 42 d increased, while renal glutathione level at 42 d decreased, when feeding broilers with the ZEN-contaminated diet (P < 0.05). Dietary modified Pal supplementation reduced hepatic malondialdehyde accumulation, whereas increased renal superoxide dismutase activity in broilers fed a ZEN-contaminated diet at 42 d (P < 0.05). This finding suggested that dietary modified Pal administration could promote growth performance, reduce hepatonephric ZEN residues, and improve liver function and antioxidant status of broiler chickens receiving a ZEN-contaminated diet.

Mycotoxins in Flanders' Fields: Occurrence and Correlations with Fusarium Species in Whole-Plant Harvested Maize

Mycotoxins are well-known contaminants of several food- and feedstuffs, including silage maize for dairy cattle. Climate change and year-to-year variations in climatic conditions may cause a shift in the fungal populations infecting maize, and therefore alter the mycotoxin load. In this research, 257 maize samples were taken from fields across Flanders, Belgium, over the course of three years (2016-2018) and analyzed for 22 different mycotoxins using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. DNA of Fusarium graminearum, F. culmorum and F. verticillioides was quantified using the quantitative polymerase chain reaction (qPCR). Multi-mycotoxin contamination occurred frequently, with 47% of samples containing five or more mycotoxins. Nivalenol (NIV) was the most prevalent mycotoxin, being present in 99% of the samples, followed by deoxynivalenol (DON) in 86% and zearalenone (ZEN) in 50% of the samples. Fumonisins (FUMs) were found in only 2% of the samples in the wet, cold year of 2016, but in 61% in the extremely hot and dry year of 2018. Positive correlations were found between DON and NIV and between F. graminearum and F. culmorum, among others. FUM concentrations were not correlated with any other mycotoxin, nor with any Fusarium sp., except F. verticillioides. These results show that changing weather conditions can influence fungal populations and the corresponding mycotoxin contamination of maize significantly, and that multi-mycotoxin contamination increases the risk of mycotoxicosis in dairy cattle.

Multiannual occurrence of mycotoxins in feed ingredients and complete feeds for pigs in the Czech Republic

The aim of the study was to evaluate the individual and combined occurrence of mycotoxins in feed ingredients and complete feeds for pigs in the Czech Republic in the years 2013–2017. The samples were analysed for the occurrence of aflatoxins (AF), deoxynivalenol (DON), zearalenone (ZEA), ochratoxin A (OTA), fumonisins (FUM), and T-2/H-2 toxins. The mycotoxin most commonly found in maize and small cereal grain samples was deoxynivalenol (94% and 53%, respectively). Deoxynivalenol was also the most frequent mycotoxin in all types of swine feed. The most frequent mycotoxin combinations in the total number of samples were DON + ZEA (56.63%), DON + OTA (11.61%) and DON + sum of T2/HT2 (9.76%). The maximum values set by the European Commission for mycotoxin levels in feed ingredients and complete feeds were exceeded in the case of AFB1, deoxynivalenol, zearalenone, ochratoxin A and T-2/H-2 toxins. Our findings support the need for further monitoring of mycotoxins in feed ingredients and complete feeds for pigs in the Czech Republic.

Mycotoxin Occurrence in Maize Silage-A Neglected Risk for Bovine Gut Health?

Forages are important components of dairy cattle rations but might harbor a plethora of mycotoxins. Ruminants are considered to be less susceptible to the adverse health effects of mycotoxins, mainly because the ruminal microflora degrades certain mycotoxins. Yet, impairment of the ruminal degradation capacity or high ruminal stability of toxins can entail that the intestinal epithelium is exposed to significant mycotoxin amounts. The aims of our study were to assess i) the mycotoxin occurrence in maize silage and ii) the cytotoxicity of relevant mycotoxins on bovine intestinal cells. In total, 158 maize silage samples were collected from European dairy cattle farms. LC-MS/MS-based analysis of 61 mycotoxins revealed the presence of emerging mycotoxins (e.g. emodin, culmorin, enniatin B1, enniatin B, and beauvericin) in more than 70% of samples. Among the regulated mycotoxins, deoxynivalenol and zearalenone were most frequently detected (67.7%). Overall, 87% of maize silages contained more than five mycotoxins. Using an in vitro model with calf small intestinal epithelial cells B, the cytotoxicity of deoxynivalenol, nivalenol, fumonisin B1 and enniatin B was evaluated (0-200 µM). Absolute IC50 values varied in dependence of employed assay and were 1.2-3.6 µM, 0.8-1.0 µM, 8.6-18.3 µM, and 4.0-6.7 µM for deoxynivalenol, nivalenol, fumonisin B1, and enniatin B, respectively. Results highlight the potential relevance of mycotoxins for bovine gut health, a previously neglected target in ruminants.

Physico-Chemical Properties of Clay Minerals and Their Use as a Health Promoting Feed Additive

The contamination of feeds with microbiological or toxicological agents can affect health, productivity and safety of livestock animals and their products. The treatment of feedstuffs to lower the content of undesired substances before feeding is expensive and labor intensive, therefore an alternative is to reduce their gastrointestinal absorption. Different feed additives are available, however the use of clays and clay minerals are ideal for this purpose due to their high specific surface area, adsorption capacity, low or null toxicity for the animal and low cost. A large number of clays available to producers have different structures that are dependent on their mining source, causing difficulty in proper categorization. For this reason properties of phyllosilicates with 1:1 layers (one sheet of SiO₄ tetrahedra joined to one sheet of Al- or Mg-octahedra), 2:1 layers (one sheet of Al- or Mg-octahedra between two sheets of Si-tetrahedra), and 2:1:1 layers (a basic 2:1 structure with an interlayer brucite (with cations Mg²⁺ or Fe²⁺) or gibbsite (with cation Al³⁺) sheet) and tectosilicates are described. The role of clay minerals in animal production shows a reduction in diarrhea, better feed conversion ratio, and improved health of many livestock species due to their specific adsorption potential of many feed mycotoxins. Overall, there is growing interest in the use of clays due to their beneficial characteristics, absence of primary toxicity and success in research to reduce animal disease and improve animal production and safety of animal products.

Zearalenone Biodegradation by the Combination of Probiotics with Cell-Free Extracts of Aspergillus oryzae and its Mycotoxin-Alleviating Effect on Pig Production Performance

In order to remove zearalenone (ZEA) detriment—Bacillus subtilis, Candida utilis, and cell-free extracts from Aspergillus oryzae were used to degrade ZEA in this study. The orthogonal experiment in vitro showed that the ZEA degradation rate was 92.27% (p < 0.05) under the conditions that Candida utilis, Bacillus subtilis SP1, and Bacillus subtilis SP2 were mixed together at 0.5%, 1.0%, and 1.0%. When cell-free extracts from Aspergillus oryzae were combined with the above probiotics at a ratio of 2:1 to make mycotoxin-biodegradation preparation (MBP), the ZEA degradation rate reached 95.15% (p < 0.05). In order to further investigate the MBP effect on relieving the negative impact of ZEA for pig production performance, 120 young pigs were randomly divided into 5 groups, with 3 replicates in each group and 8 pigs for each replicate. Group A was given the basal diet with 86.19 μg/kg ZEA; group B contained 300 μg/kg ZEA without MBP addition; and groups C, D, and E contained 300 μg/kg ZEA added with 0.05%, 0.10%, and 0.15% MBP, respectively. The results showed that MBP addition was able to keep gut microbiota stable. ZEA concentrations in jejunal contents in groups A and D were 89.47% and 80.07% lower than that in group B (p < 0.05), indicating that MBP was effective in ZEA biodegradation. In addition, MBP had no significant effect on pig growth, nutrient digestibility, and the relative mRNA abundance of estrogen receptor alpha (ERα) genes in ovaries and the uterus (p > 0.05).

Occurrence of Mycotoxins in Extruded Commercial Cat Food

The occurrence of the most important mycotoxins (deoxynivalenol, fumonisin B1 and B2, aflatoxins B1, B2, G1, and G2, ochratoxin A, zearalenone, T-2, and HT-2 toxins) was determined in 64 extruded cat foods purchased in Italy through ultra-performance liquid chromatography coupled with tandem mass spectrometry. Deoxynivalenol and fumonisins were the most common contaminants (quantified in 80 and 95% of the samples, respectively). Conversely, aflatoxins B2, G1, and G2 were not identified in any sample. Some cat foods exceeded the regulatory limit for aflatoxin B1 (n = 3) or the guidance values for zearalenone (n = 3), fumonisins (n = 2), ochratoxin A (n = 1), and T-2 (n = 1) recently established for pets in the European Union. A widespread co-occurrence of mycotoxins was observed (28, 42, and 8% of the samples contained quantifiable amounts of two, three, and four mycotoxins, respectively). This study describes criticisms regarding the mycotoxin issue in pet food and suggests an improvement of the monitoring of the pet food chain.

Mycotoxins occurrence and fungal populations in different types of silages for dairy cows in Spain

Silages constitute a major component of the feed ration for dairy cows, being a potential source of mycotoxins due to the possible contamination by filamentous fungi capable of producing these toxic compounds. In this study, samples of different kinds of silages collected from farms located in four regions of Spain, were analysed to evaluate the occurrence of aflatoxins (AFs) and Fusarium mycotoxins. Lactic acid bacteria and fungal populations as well as pH and water activity were also studied. Penicillium, Geotrichum and Monascus were the main fungi identified in all the silages examined. The incidence of AFs was low (10 % of positive samples). Fusarium mycotoxins were detected in 40 % of the samples and fumonisins (FBs) were the most commonly detected. Maize silage was the most heavily contaminated type of silage. Levels of mycotoxins detected in positive samples did not exceed the EU guidance values. The lack of relationship between Fusarium counts and its mycotoxin concentrations suggested that mycotoxin production possibly occurred pre-ensiling or immediately post-ensiling. Outcomes showed that mould growth and mycotoxin contamination in silages should be regularly monitored in order to minimize the exposure of dairy cows to contaminated feed.

Lack of Toxic Interaction Between Fusariotoxins in Broiler Chickens Fed throughout Their Life at the Highest Level Tolerated in the European Union

Fusarium mycotoxins (FUS) occur frequently in poultry diets, and regulatory limits are laid down in several countries. However, the limits were established for exposure to a single mycotoxin, whereas multiple contamination is more realistic, and different studies have demonstrated that it is not possible to predict interactions between mycotoxins. The purpose of this study was thus to compare the toxic effect of deoxynivalenol (DON), fumonisins (FB) and zearalenone (ZON), alone and in combination on broiler chickens, at the maximum tolerated level established by the EU for poultry feed. Experimental corn-soybean diets incorporated ground cultured toxigenic Fusarium strains. One feed was formulated for chickens 0 to 10 days old and another for chickens 11 to 35 days old. The control diets were mycotoxin free, the DON diets contained 5 mg DON/kg, the FB diet contained 20 mg FB1 + FB2/kg, and the ZON diet contained 0.5 mg ZON/kg. The DONFBZON diet contained 5, 20, and 0.5 mg/kg of DON, FB1 + FB2, and ZON, respectively. Diets were distributed ad libitum to 70 broilers (male Ross PM3) separated into five groups of 14 chickens each reared in individual cages from one to 35 days of age. On day 35, after a starvation period of 8 h, a blood sample was collected, and all the animals were killed and autopsied. No difference between groups that could be attributed to FUS was observed in performances, the relative weight of organs, biochemistry, histopathology, intestinal morphometry, variables of oxidative damage, and markers of testicle toxicity. A significant increase in sphinganine and in the sphinganine to sphingosine ratio was observed in broilers fed FB. Taken together, these results suggest that the regulatory guidelines established for single contamination of broiler chickens fed with DON, FB, and ZON can also be used in the case of multiple contamination with these toxins.

Microbial synthesis of zinc oxide nanoparticles and their potential application as an antimicrobial agent and a feed supplement in animal industry: a review

In recent years, zinc oxide nanoparticles (ZnO NPs) have gained tremendous attention attributed to their unique properties. Notably, evidence has shown that zinc is an important nutrient in living organisms. As such, both prokaryotes and eukaryotes including bacteria, fungi and yeast are exploited for the synthesis of ZnO NPs by using microbial cells or enzyme, protein and other biomolecules compounds in either an intracellular or extracellular route. ZnO NPs exhibit antimicrobial properties, however, the properties of nanoparticles (NPs) are depended upon on their size and shape, which make them specific for various applications. Nevertheless, the desired size and shape of NPs can be obtained through the optimization process of microbes mediated synthesis by manipulating their reaction conditions. It should be noted that ZnO NPs are synthesized by various chemical and physical methods. Nonetheless, these methods are expensive and not environmentally friendly. On that account, the microbes mediated synthesis of ZnO NPs have rapidly evolved recently where the microbes are cleaner, eco-friendly, non-toxic and biocompatible as the alternatives to chemical and physical practices. Moreover, zinc in the form of NPs is more effective than their bulk counterparts and thus, they have been explored for many potential applications including in animals industry. Notably, with the advent of multi-drug resistant strains, ZnO NPs have emerged as the potential antimicrobial agents. This is mainly due to their superior properties in combating a broad spectrum of pathogens. Moreover, zinc is known as an essential trace element for most of the biological function in the animal's body. As such, the applications of ZnO NPs have been reported to significantly enhance the health and production of the farm animals. Thus, this paper reviews the biological synthesis of ZnO NPs by the microbes, the mechanisms of the biological synthesis, parameters for the optimization process and their potential application as an antimicrobial agent and feed supplement in the animal industry as well as their toxicological hazards on animals.

Prevalent Mycotoxins in Animal Feed: Occurrence and Analytical Methods

Today, we have been witnessing a steady tendency in the increase of global demand for maize, wheat, soybeans, and their products due to the steady growth and strengthening of the livestock industry. Thus, animal feed safety has gradually become more important, with mycotoxins representing one of the most significant hazards. Mycotoxins comprise different classes of secondary metabolites of molds. With regard to animal feed, aflatoxins, fumonisins, ochratoxins, trichothecenes, and zearalenone are the more prevalent ones. In this review, several constraints posed by these contaminants at economical and commercial levels will be discussed, along with the legislation established in the European Union to restrict mycotoxins levels in animal feed. In addition, the occurrence of legislated mycotoxins in raw materials and their by-products for the feeds of interest, as well as in the feeds, will be reviewed. Finally, an overview of the different sample pretreatment and detection techniques reported for mycotoxin analysis will be presented, the main weaknesses of current methods will be highlighted.

Feed preference and feeding behaviours in grower broilers fed diets containing wheat naturally contaminated with fusarium mycotoxins

1. Two trials were conducted to determine the effect of feeding diets contaminated with fusarium mycotoxins (primarily deoxynivalenol (DON)) on broiler chicken feed preference, feeding behaviour and growth performance. 2. A total of 120 male Ross 308 chicks (4 birds/cage, 30 cages) were fed a common corn-based starter diet from 1 to 20 d of age. At 21 d, 15 cages were randomly assigned to the feed preference trial or a feeding behaviour trial. Three wheat-based experimental diets (0.14, 2.27 and 5.84 mg/kg DON) were prepared with a clean wheat and a naturally contaminated wheat. Broilers were ad libitum fed the experimental diets during 21-27 d. 3. In the preference trial, each cage's feeder was split into two equal-sized compartments so birds were provided a choice of two diets (control vs. low, control vs. high and low vs. high DON). In the feeding behaviour trial, diets were randomly assigned to 15 cages (5 cages/diet). Feeding and drinking behaviour was recorded for 1 h before and after the dark period and 1-h period at 9 h after the light was turned on (middle of day). Growth performance was assessed at 27 d. 4. In the preference trial, broilers preferred the control diet over low (93.0 vs. 66.1 g/d, P < 0.01) and high (104.4 vs. 50.4 g/d, P < 0.01) DON diets. At all three timepoints, where behaviour was recorded, birds offered the DON diets spent more time at the feeder compared to birds provided control diets (P < 0.05). Control birds had lower feed to gain ratio (1.65) than birds fed low (1.82) and high (1.94) DON diets (P < 0.01). 5. It is clear that broilers are sensitive to the presence of fusarium mycotoxins and that moderate levels of DON negatively affect feed preference and growth performance when fed during the grower period.

Frequency and levels of regulated and emerging mycotoxins in silage in Poland

In this study, 120 silage samples collected in 2015 from farms in Poland were analysed by a multimycotoxin method based on liquid chromatography coupled with tandem mass spectrometry. The study included toxins which are regulated within the European Union (aflatoxins, deoxynivalenol, fumonisins, T-2/HT-2 toxins, ochratoxin A and zearalenone) and non-regulated mycotoxins (enniatins, beauvericin, 8-ketotrichothecenes, sterigmatocystin, zearalenone derivatives). All silage samples were positive for at least one mycotoxin, and 61% of samples contained five or more mycotoxins simultaneously. The most frequently detected toxins were deoxynivalenol, nivalenol, zearalenone, enniatins and beauvericin, although the levels of these toxins were relatively low. The mean concentration of deoxynivalenol and zearalenon was 406 and 80.6 μg/kg, respectively, and two toxins were positive-correlated. This is the first study that provides information about emerging mycotoxins contaminating silage in Poland.

Silage review: Mycotoxins in silage: Occurrence, effects, prevention, and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.

Performance effects of feed-borne Fusarium mycotoxins on broiler chickens: Influences of timing and duration of exposure

In commercial practice, broiler chickens may be exposed to Fusarium mycotoxins either during specific growth stages or throughout the entire production cycle. A 34-day feeding trial was conducted to identify sensitive periods for mycotoxin effects during the growth cycle of broiler chickens. A total of 420 newly-hatched Ross 308 male broilers were randomly assigned to 60 cages with 7 birds/cage. Sources of clean wheat (<0.5 mg/kg deoxynivalenol [DON]) and Fusarium-contaminated wheat (11.4 mg/kg DON) were used to formulate the starter diets (0.41 and 6.62 mg/kg DON) provided from 1 to 21 d of age and the grower diets (0.54 and 7.90 mg/kg DON) provided from 22 to 34 d. Control and DON diets were provided to broilers according to treatments (control, DON 1 to 14 d, DON 15 to 21 d, DON 22 to 34 d and DON 1 to 34 d). Birds were monitored daily for morbidity or mortality. Broiler growth performance (body weight, average daily gain, average daily feed intake and feed to gain ratio) was measured weekly. Segments of duodenum, jejunum and ileum were collected at 21 and 34 d and morphometric parameters (villus height, crypt depth, villus width, muscularis thickness and villi:crypt ratio) were measured. Birds fed the DON starter diet during the first 14 d did not exhibit any changes in growth performance; however, growth performance was suppressed in birds fed DON-contaminated diets during the grower period (22 to 34 d). At 34 d, birds that received the DON grower diet (DON 22 to 34 d and DON 1 to 34 d) were lighter (1,433 vs. 1,695 g) than birds fed the control diet. Feed to gain ratio was higher in birds fed the DON grower diet from 22 to 28 d (1.77 vs. 1.56) and 28 to 34 d (2.24 vs. 1.85) compared with corresponding controls. These results suggest that providing older broiler chicks (22 to 34 d) feed contaminated with Fusarium mycotoxins (specifically DON) may result in production losses. Histopathological analysis of the ileum region revealed that birds provided the DON diets throughout the entire trial (1 to 34 d) had shorter villi (506 vs. 680 μm) and shallower crypt (85 vs. 115 μm) than control birds. Taken together, these results indicate that DON-induced growth suppression may be a result of adverse effects on intestinal morphology during later growth phases of broilers.

Risks for animal health related to the presence of fumonisins, their modified forms and hidden forms in feed

Fumonisins, mycotoxins primarily produced by Fusarium verticillioides and Fusarium proliferatum, occur predominantly in cereal grains, especially in maize. The European Commission asked EFSA for a scientific opinion on the risk to animal health related to fumonisins and their modified and hidden forms in feed. Fumonisin B1 (FB 1), FB 2 and FB 3 are the most common forms of fumonisins in feedstuffs and thus were included in the assessment. FB 1, FB 2 and FB 3 have the same mode of action and were considered as having similar toxicological profile and potencies. For fumonisins, the EFSA Panel on Contaminants in the Food Chain (CONTAM) identified no-observed-adverse-effect levels (NOAELs) for cattle, pig, poultry (chicken, ducks and turkeys), horse, and lowest-observed-adverse-effect levels (LOAELs) for fish (extrapolated from carp) and rabbits. No reference points could be identified for sheep, goats, dogs, cats and mink. The dietary exposure was estimated on 18,140 feed samples on FB 1-3 representing most of the feed commodities with potential presence of fumonisins. Samples were collected between 2003 and 2016 from 19 different European countries, but most of them from four Member States. To take into account the possible occurrence of hidden forms, an additional factor of 1.6, derived from the literature, was applied to the occurrence data. Modified forms of fumonisins, for which no data were identified concerning both the occurrence and the toxicity, were not included in the assessment. Based on mean exposure estimates, the risk of adverse health effects of feeds containing FB 1-3 was considered very low for ruminants, low for poultry, horse, rabbits, fish and of potential concern for pigs. The same conclusions apply to the sum of FB 1-3 and their hidden forms, except for pigs for which the risk of adverse health effect was considered of concern.

A review of the mycotoxin adsorbing agents, with an emphasis on their multi-binding capacity, for animal feed decontamination

Contamination of animal feed with mycotoxins still occurs very often, despite great efforts in preventing it. Animal feeds are contaminated, at low levels, with several mycotoxins, particularly with those produced by Aspergillus and Fusarium genera (Aflatoxin B_1, Ochratoxin A, Zearalenone, Deoxynivalenol and Fumonisina B₁). In animal feed, to date, only Aflatoxin B₁ is limited through EU regulation. Consequently, mycotoxins cause serious disorders and diseases in farm animals. In 2009, the European Union (386/2009/EC) approved the use of mycotoxin-detoxifying agents, as feed additives, to prevent mycotoxicoses in farm animals. The present review gives an overview of the problem of multi-mycotoxin contamination of feed, and aims to classify mycotoxin adsorbing agents (minerals, organic, and synthetic) for feed decontamination, focusing on adsorbents with the ability to bind to multiple mycotoxins, which should have a more effective application in farms but they are still little studied in scientific literature.

A Decrease of Incidence Cases of Fumonisins in South Korean Feedstuff between 2011 and 2016

Several plant pathogen Fusarium species produce fumonisins (FUMs); which can end up in food and feed and; when ingested; can exhibit harmful effects on humans and livestock. Mycotoxin intoxication by fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) can cause porcine pulmonary edema; leukoencephalomalacia in equines; esophageal cancer and birth defects by natural contamination. Herein; the occurrence of FB₁ and FB₂ in feedstuff (compound feed and feed ingredients) was investigated between 2011 and 2016 in South Korea. A total of 535 animal feed samples (425 compound feed samples and 110 feed ingredients) produced domestically were sampled four times between 2011 and 2016 (2011; 2012; 2014 and 2016) from feed factories in South Korea. The limit of detection (LOD) for FB₁ and FB₂ was 20 μg/kg and 25 μg/kg; respectively; and the limit of quantitation (LOQ) was 30 μg/kg and 35 μg/kg; respectively. The recovery range (%) was between 86.4% and 108.8%; and the relative standard deviation (RSD) (%) was 4.7-12.1%. Seven (swine feed samples) out of the 425 feed samples exceeded the European Union (EU) and South Korea commission regulations over the six-year test period; and no feed ingredients exceeded the guidelines.