Toxicological evaluations of cyclopiazonic acid and ochratoxin A in broilers

Mycotoxins in Poultry Feed and Feed Ingredients from Sub-Saharan Africa and Their Impact on the Production of Broiler and Layer Chickens: A Review

The poultry industry in sub-Saharan Africa (SSA) is faced with feed insecurity, associated with high cost of feeds, and feed safety, associated with locally produced feeds often contaminated with mycotoxins. Mycotoxins, including aflatoxins (AFs), fumonisins (FBs), trichothecenes, and zearalenone (ZEN), are common contaminants of poultry feeds and feed ingredients from SSA. These mycotoxins cause deleterious effects on the health and productivity of chickens and can also be present in poultry food products, thereby posing a health hazard to human consumers of these products. This review summarizes studies of major mycotoxins in poultry feeds, feed ingredients, and poultry food products from SSA as well as aflatoxicosis outbreaks. Additionally reviewed are the worldwide regulation of mycotoxins in poultry feeds, the impact of major mycotoxins in the production of chickens, and the postharvest use of mycotoxin detoxifiers. In most studies, AFs are most commonly quantified, and levels above the European Union regulatory limits of 20 μg/kg are reported. Trichothecenes, FBs, ZEN, and OTA are also reported but are less frequently analyzed. Co-occurrences of mycotoxins, especially AFs and FBs, are reported in some studies. The effects of AFs on chickens' health and productivity, carryover to their products, as well as use of mycotoxin binders are reported in few studies conducted in SSA. More research should therefore be conducted in SSA to evaluate occurrences, toxicological effects, and mitigation strategies to prevent the toxic effects of mycotoxins.

Detection of aflatoxin producing Aspergillus flavus from animal feed in Karnataka, India

Aflatoxins are toxic carcinogenic secondary metabolite produced by Aspergillus flavus and are responsible for contamination in animal feed. The aim of the study was to determine the prevalence of aflatoxin contamination in animal feed in Karnataka state, India. The screening was performed by desiccated coconut agar and quantification of aflatoxin by liquid ammonia vapor test, TLC and ELISA. A total of 29 samples received from different places of Karnataka were analysed for aflatoxin B1. Out of 29 animal feed sample aflatoxin B1 detected in 12 samples representing 41.38% at average concentration of 288.50 μg/kg. Out of 42 isolates screened in animal feed, Aspergillus flavus was found to be in 86.2% and Aspergillus niger was 24.1%. It was observed that out of 42 isolates analyzed from animal feed, aflatoxin B1 was detected in 12 samples. Aflatoxin B1 is the most common contaminant and the method is more sensitive in screening and detection of aflatoxin B1 in the animal feed.

Impact of Chronic Levels of Naturally Multi-Contaminated Feed with Fusarium Mycotoxins on Broiler Chickens and Evaluation of the Mitigation Properties of Different Titers of Yeast Cell Wall Extract

The chronic intake of naturally multi-mycotoxin contaminated feed by broilers with or without titers of Yeast Cell Wall Extract (YCWE, a.k.a Mycosorb A+®), was investigated. Day-old male Cobb chicks (1600 birds, 64 pens, 25 birds/pen) were randomly allocated to diets of control (CON); diet containing mycotoxins (MT); CON + 0.2% YCWE; MT + 0.025% YCWE; MT + 0.05% YCWE; MT + 0.1% YCWE; MT + 0.2% YCWE; and MT + 0.4% YCWE. Growth performance, blood biochemical parameters and gut health were recorded over 42 days. Compared with CON, MT had reduced body weight (BW) and increased feed conversion ratio (FCR) on days 35 and 42 with increased duodenal crypt depth and fewer goblet cells. Furthermore, European Poultry Production Efficiency (EPEF) was reduced for MT versus CON. Feeding MT + 0.2% YCWE improved BW, lowered FCR, reduced crypt depth, increased goblet cell count and improved EPEF. Considering titration of YCWE (0 to 0.4%) during mycotoxin challenge, a cubic effect was observed for FCR with NC + 0.2% YCWE having the lowest FCR. These findings suggest that chronic consumption of multiple Fusarium mycotoxins present in common field concentrations can negatively impact broiler performance and gut health while inclusion of YCWE, particularly 0.2%, could be effective in counteracting mycotoxins.

Effects of ochratoxin A on membrane phospholipids of the intestine of broiler chickens, practical consequences

Ochratoxin A (OTA) is a mycotoxin produced by various species of Aspergillus and Penicillium. Ochratoxin A was classified as a group 2B carcinogen and is one of the major intestinal pathogenic mycotoxins. One of the most frequent modes of intoxication is consumption of contaminated food with mycotoxins. Feed represents the major cost and has a direct impact on the economical viability of broiler's production system, since it must contain the necessary elements that allow the animal to express the maximum genetic potential while providing its nutritional requirements. Thus, the animal has to digest the feed and absorb its nutrients, which is in direct correlation with the gastrointestinal tract, especially the small intestine and the development of the mucosal surface area. Once ingested, OTA is absorbed by passive diffusion, mainly the jejunum. Ochratoxin A's presence affects lipid membranes and could lead to the degradation of their normal structure and functionality. All of these effects contribute to the development of malabsorption. It was very interesting to study the effect of OTA on the layer of phospholipids of the bowel. The experimental group received OTA (0.05 to mg/kg BW) through an intra-peritoneal injection, every other day for 21 days. We noted that feed conversion ratio and average daily gain were reduced. Histological studies showed important alterations at the level of the mucosal membrane of the intestine (villosities, crypts) following intra-peritoneal administration of the mycotoxin. Thinning and enlargement at the base of the villosities, hyperplasia and crypts in irregular forms, blunting and denudation were observed through the examination of intestinal morphology. Biochemical studies, such as total lipid and phospholipid compositions, allowed us to have more detailed results. All identified mucosal phospholipids were modified, particularly the phosphatidylcholine (PC) and the phosphatidylethanolamine (PE) in the jejunum mucosa. In fact, there was a decrease by 55.81% for PC, 56.66% for PE, while a significant increase by 32.91% was noted for phosphatidylserine in the jejunum. It was very interesting to study the effect of OTA on the phospholipids layer of the bowel, as the mucous membrane of the small intestine represents the main site of absorption and transformation of nutriments. To avoid such disturbances and prevent the effects of the OTA, precautions must be taken to inhibit mold growth at the level of the feed manufactory units. Phosphatidylcholine and PE administrations may represent an option that could allow reestablishment of phospholipid equilibrium in the intestine.

Long-Term Effects of Ochratoxin A on the Glutathione Redox System and Its Regulation in Chicken

The purpose of this study was to evaluate the effect of three-weeks ochratoxin A (OTA) exposure on some lipid peroxidation parameters, reduced glutathione concentration and glutathione-peroxidase activity, as well as expression of oxidative stress response-related (KEAP1, NRF2) and glutathione system (GPX3, GPX4, GSS, GSR) genes in chickens. Three levels of exposure (106, 654 and 1126 μg/kg feed) were applied. The results showed that OTA initiated free radical formation, which was suggested by the increase in the malondialdehyde content in the liver and kidney, which was more marked in the liver, depending on the length of exposure and dose. Reduced glutathione concentration increased as an effect of the highest OTA dose in blood plasma and in liver, but not in red blood cell hemolysates and the kidney. Glutathione peroxidase activity did not change in the blood and showed increasing tendency in the liver, and significant increase in the kidney. Expression of KEAP1 gene showed up-regulation in the liver, and down-regulation in the kidney, but overexpression of NRF2 gene was found in the liver and kidney at the highest dose. However, down-regulation of Nrf2 dependent genes, GPX3, GPX4, GSS and GSR, suggested an improper antioxidant response at the protein level, thus oxidative stress occurred, even at the dose of the EU regulatory limit for poultry diets.

Identification of Aspergillus flavus and aflatoxin in home mix layer poultry feed in relation to seasons in Karachi, Pakistan

Fungal toxins in feed are leading issue in poultry industry causing a detrimental effect on the performance and health of poultry. The study was carried out to determine the incidence and concentration of the aflatoxins and their major producer Aspergillus flavus in home mix layer poultry feed in respect of seasonal variation throughout the year. A total of (n = 204) home mix poultry layer feed samples were analyzed for the isolation of fungi. The isolates were initially screened through colony morphology and microscopic examination. However, aflatoxin concentration was determined by ELISA. Revealed results indicated that, the highest percentage of A. flavus was found during the months of June to August 50/54 (92.5%) followed by September to November 43/65 (66.1%), March to May 21/40 (52.5%), and December to February 18/45 (40%). As a whole, the incidence was recorded 132/204 (64.7%). Moreover, of the 132 samples, 41 (31%) were exceeded in respect of aflatoxin contamination from the legal limit (20 μg/kg) imposed by Food Drug Association (FDA). Statistically, the growth of A. flavus and aflatoxin production was found significantly different in respect of seasonal variation. As highest total viable fungal count (9.9 × 10⁴ CFU/g) and aflatoxin level (72.27 μg/kg) were recorded during the months of June to August and lowest in December to February. Consequently, instantaneous essential control measures are demanded regarding appropriate storage and adequate drying in post-harvesting season. Along with surveillance plans and austere regulations for monitoring the aflatoxin contents for the wellbeing of consumers.

Cyclopiazonic acid: 50th anniversary of its discovery

In 1968, the mycotoxin cyclopiazonic acid (CPA) was first discovered and characterised as a chemical substance. Within the following five decades, much has been learned from the results of CPA research. CPA is produced by several Penicillium species (P. griseofulvum, P. camemberti, P. commune, P. dipodomyicola) and Aspergillus species (A. flavus, A. oryzae and A. tamarii). It is widespread on naturally contaminated agricultural raw materials. CPA has been reported to occur in food commodities (e.g. oilseeds, nuts, cereals, dried figs, milk, cheese and meat products) and to possess toxicological significance. CPA is also frequently detected in peanuts and maize; the presence of CPA and aflatoxins in maize and peanuts contaminated with A. flavus suggests that synergism may occur. CPA is toxic to several animal species, such as rats, pigs, guinea pigs, poultry and dogs. After ingesting CPA-contaminated feeds, test animals display severe gastrointestinal upsets and neurological disorders. Organs affected include the liver, kidney, heart, and digestive tract, which show degenerative changes and necrosis. Biologically, CPA is a specific inhibitor of sarco(endo)plasmic reticulum Ca2+-ATPase. Data from toxicological evaluation of aflatoxins and CPA in broiler chickens demonstrate that both aflatoxins and CPA alone and the aflatoxin-CPA combination can adversely affect broiler health. The effects of aflatoxins and CPA combination were additive in most cases.

Isolation and characterization of Aspergillus flavus strains in China

Important staple foods (peanuts, maize and rice) are susceptible to contamination by aflatoxin (AF)-producing fungi such as Aspergillus flavus. The objective of this study was to explore non-aflatoxin-producing (atoxigenic) A. flavus strains as biocontrol agents for the control of AFs. In the current study, a total of 724 A. flavus strains were isolated from different regions of China. Polyphasic approaches were utilized for species identification. Non-aflatoxin and non-cyclopiazonic acid (CPA)-producing strains were further screened for aflatoxin B₁ (AFB₁) biosynthesis pathway gene clusters using a PCR assay. Strains lacking an amplicon for the regulatory gene aflR were then analyzed for the presence of the other 28 biosynthetic genes. Only 229 (32%) of the A. flavus strains were found to be atoxigenic. Smaller (S) sclerotial phenotypes were dominant (51%) compared to large (L, 34%) and non-sclerotial (NS, 15%) phenotypes. Among the atoxigenic strains, 24 strains were PCR-negative for the fas-1 and aflJ genes. Sixteen (67%) atoxigenic A. flavus strains were PCRnegative for 10 or more of the biosynthetic genes. Altogether, 18 new PCR product patterns were observed, indicating great diversity in the AFB₁ biosynthesis pathway. The current study demonstrates that many atoxigenic A. flavus strains can be isolated from different regions of China. In the future laboratory as well as field based studies are recommended to test these atoxigenic strains as biocontrol agents for aflatoxin contamination.

Gene expression in the kidneys of broilers fed ochratoxin A for different time periods

Consumption of ochratoxin A (OTA) contaminated diets by broilers results in economic losses to the poultry industry. This experiment evaluated the effects of quantity and time of exposure to dietary OTA on performance, organ weights, serum biochemistry, and renal gene expression of chicks. Determination of genes expressed in response to OTA will allow for the identification of pathways that are influenced by OTA. 180-day old male broiler chicks were randomly assigned to a 3×3 factorial arrangement of treatments (3 levels of OTA; 0, 1 and 2 mg OTA/kg diet and 3 time periods; 7, 14 and 21 days) with 4 replicate pens of 5 birds each per treatment. For RNA-sequencing analysis (RNA-Seq), kidney samples were collected weekly from 3 controls and 3 chicks fed 1 mg OTA/kg. NextGENe software was used for read alignment and transcript quantification. Birds fed 2 mg OTA/kg diet had decreased feed intake and body weight gain, and increased serum uric acid on days 14 and 21. Compared to controls, birds fed 2 mg OTA/kg diet also had poorer feed conversion and increased kidney weights. On day 21, birds fed 1 mg OTA/kg diet had decreased albumin, and aspartate aminotransferase concentrations. Genes associated with carbohydrate and amino acid metabolism were downregulated, and genes associated with the immune system were upregulated at days 7 and 14. Genes associated with lipid metabolism and xenobiotic biodegradation were also downregulated on day 14. These changes disappeared on day 21 suggesting that the kidney and other related organs were repaired or the damage was contained. In conclusion, decreased performance and increased kidney weight and serum uric acid in birds fed 2 mg OTA/kg confirmed the effects of OTA. Supplementation of 1 mg OTA/kg diet caused time-dependent alterations in renal gene expression in chicks.

Characterization of aflatoxin producing Aspergillus flavus from food and feed samples

Aspergillus flavus is one of the major producers of aflatoxin and can contaminate wide range of agricultural commodities either in field or in storage. 15 presumptive Aspergillus flavus has been isolated from 30 feed and grain samples. All the isolates were morphologically similar to Aspergillus flavus type strains. All the isolates were found to be aflatoxigenic. DNA sequencing of 5.8 s rDNA confirmed all of them to be Aspergillus flavus. Only 1 isolate possessed all the seven toxigenic gene (aflR, aflS, aflQ, aflP, aflD, aflM, and aflO) while aflP & aflQ were most prevalent in the isolates. All the isolates possessed at least three toxigenic genes. Toxin producing ability in solid culture media showed that 11 isolates isolates were able to produce both aflatoxin B1 & B2. More than 90% isolates produced aflatoxin B1 ranging 7–22 μg/g of agar. This study alarms us about the potential risks of Aspergillus flavus to public health if contaminate agricultural commodities such as grains or raw materials such as poultry feed. Proper harvest and storage management is required to reduce the risk of aflatoxin in feed and grains.

Gizzard erosion and ulceration syndrome in chickens and turkeys: a review of causal or predisposing factors

Gizzard erosion and ulceration syndrome (GEU) was described for the first time in the 1930s. The main focus of early studies was on nutritional deficiencies and peroxidation of highly polyunsaturated fatty acids as causative factors. During the 1970s and 1980s the focus was moved towards toxic substances in the feed. Scott's review in 1985 concluded that overproduction of gastric acid induced by gizzerosine was a major cause of GEU. During the last decades, serotype 1 of fowl adenovirus A and Clostridium perfringens have been implicated as important pathogenic agents in the development of GEU in chickens. Although GEU is globally distributed and its subclinical form appears to be common in commercial poultry flocks, the condition is rarely mentioned in standard textbooks on poultry health. This regrettable fact is probably due in part to the lack of one definitive cause of the syndrome.

Meta-analytical study of productive and nutritional interactions of mycotoxins in broilers

A meta-analysis was carried out to study the association of mycotoxins with performance, productive indices, and organ weights in broilers. Ninety-eight papers published between 1980 and 2009 were used, totaling 1,401 diets and 37,371 animals. Meta-analysis followed 3 sequential analyses: graphical, correlation, and variance-covariance. The mycotoxin presence in diets reduced (P < 0.05) feed intake by 12% and weight gain by 14% compared with control group. Ochratoxins and aflatoxins were the mycotoxins with the greatest effect on feed intake and bird growth, reducing (P < 0.05) feed ingestion by 17 and 11%, respectively, and weight gain by 20 and 11%, respectively. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination for equations to estimate mycotoxin effect on weight gain. The mycotoxin effect on growth proved to be greater in young poultry. The residual analysis revealed that 65% of the variation in weight gain was explained by feed intake. The variation in weight gain of challenged broilers in relation to nonchallenged broilers was also influenced by ingestion of nutrients such as protein and methionine. Mortality was 8.8 and 2.8 times greater (P < 0.05) in groups that received diets with deoxynivalenol and aflatoxins, respectively. Mycotoxins also increased (P < 0.05) the relative weight of liver by 15%, of kidneys by 11%, of lungs by 9%, and of gizzard by 3%. Mycotoxins influenced broiler performance, productive indices, and organ weights. However, the magnitude of the effects varied with type and concentration of mycotoxin, animal age, and nutritional factors.

Mycotoxin co-contamination of food and feed: meta-analysis of publications describing toxicological interactions

Most fungi are able to produce several mycotoxins simultaneously; moreover food and feed can be contaminated by several fungi species at the same time. Thus, humans and animals are generally not exposed to one mycotoxin but to several toxins at the same time. Most of the studies concerning the toxicological effect of mycotoxins have been carried out taking into account only one mycotoxin. In the present review, we analysed 112 reports where laboratory or farm animals were exposed to a combination of mycotoxins, and we determined for each parameter measured the type of interaction that was observed. Most of the published papers concern interactions with aflatoxins and other mycotoxins, especially fumonisins, ochratoxin A and trichothecenes. A few papers also investigated the interaction between ochratoxin A and citrinin, or between different toxins from Fusarium species. Only experiments with a 2×2 factorial design with individual and combined effects of the mycotoxins were selected. Based on the raw published data, we classified the interactions in four different categories: synergistic, additive, less than additive or antagonistic effects. This review highlights the complexity of mycotoxins interactions which varies according to the animal species, the dose of toxins, the length of exposure, but also the parameters measured.

An industry perspective on the use of "atoxigenic" strains of Aspergillus flavus as biological control agents and the significance of cyclopiazonic acid

Several nonaflatoxigenic strains of Aspergillus flavus have been registered in the United States to reduce aflatoxin accumulation in maize and other crops, but there may be unintended negative consequences if these strains produce cyclopiazonic acid (CPA). AF36, a nonaflatoxigenic, CPA-producing strain has been shown to produce CPA in treated maize and peanuts. Alternative strains, including Afla-Guard® brand biocontrol agent and K49, do not produce CPA and can reduce both aflatoxin and CPA in treated crops. Chronic toxicity of CPA has not been studied, and recent animal studies show significant harmful effects from short-term exposure to CPA at low doses. Grower and industry confidence in this approach must be preserved through transparency.

Ochratoxin A in feed of food-producing animals: an undesirable mycotoxin with health and performance effects

Mycotoxins are secondary fungal metabolites, whose presence in feed- and foodstuffs is unavoidable. Ochratoxin A (OTA) is one of the known mycotoxins with greatest public health and agro-economic significance. Several toxic effects have been ascribed following exposure, namely nephrotoxicity, as well negative impacts in the performance of farm animals, resulting in major economic implications. Of no less importance for the route of human exposure that can also embody the carry-over of OTA from feed into animal-derived products is also a concern. For all these reasons the present article updates the worldwide occurrence of OTA in different raw ingredients and finished feed destined to food-producing animals. After that a brief characterization of specie susceptibility and the major rationales is made. An historical overview of field outbreaks linked to OTA exposure in farm animals, concerning the implicated feeds, contamination levels and major clinical and productivity effects is presented. Finally a review of the major animal health and performance potential impacts of animals being reared on contaminated feed is made allied to a perspective regarding its co-occurrence with other mycotoxins, and simultaneous parasitic and bacterial infections. Ultimately, this article aims to be instructive and draw attention to a mycotoxin so often neglected and elapsed from the list of differential diagnosis in farm practice. For the unpredictability and unavoidability of occurrence, OTA will definitely be an enduring problem in animal production.

Use ofTrichosporon mycotoxinivoransto suppress the effects of ochratoxicosis on the immune system of broiler chicks

(1) The objective of this study was to determine whether the dietary inclusion of Trichosporon mycotoxinivorans (TRM) could suppress the detrimental effects of ochratoxin A (OTA) on the immune system of broiler chicks. (2) Six experimental treatments were tested in 300 1-d-old broiler chicks. Treatments included addition to a standard broiler ration of neither OTA nor TRM (Diet 1), OTA alone (500 microg/kg), OTA plus TRM at three inclusion rates (10(4) CFU/g of feed, 10(5) CFU/g, 10(6) CFU/g) and TRM alone at 10(5) CFU/g of feed. The ration was fed to chicks for 42 d. (3) Blood samples were collected at d 10, 20, 30 and 40 and macrophages and heterophils were isolated. The following variables were determined in macrophages and heterophils activated by phorbol myristate acetate (65 microM): cell viability, total cell-associated urokinase-plasminogen activator (u-PA), membrane-bound u-PA, free u-PA binding sites and superoxide production. (4) There was a decrease in the viability of macrophages and heterophils from chicks receiving OTA-contaminated feed compared to the viability of cells from control birds at d 40. Dietary TRM completely blocked the effect of OTA on cell viability; all three inclusion rates were equally effective. There was a decrease in total cell-associated and membrane-bound u-PA in macrophages and heterophils of chicks receiving OTA-contaminated feed compared to the corresponding values in control birds for heterophils at d 30 and 40 and for the macrophages at d 40. (5) Similarly, dietary TRM abolished the effect of OTA on total cell-associated and membrane-bound u-PA activity. All three inclusion rates of yeast were equally effective. Heterophils, but not macrophages, isolated from chicks receiving OTA-contaminated diet produced less superoxide anion compared to all other diet groups at d 30 and 40. (6) The immune system is a primary target of OTA toxicity in broilers: several functional properties of macrophages and heterophils were depressed in chicks fed OTA-contaminated feed. There was a delay of 30d before the immunosuppressive effect became apparent. The dietary inclusion of TRM completely blocked the detrimental effects of OTA on several immune properties in broilers.

Cyclopiazonic acid augments the hepatic and renal oxidative stress in broiler chicks

Generation of reactive oxygen species (ROS) leads to serious tissue injuries. The effect of cyclopiazonic acid (CPA) on oxidative stress markers in the liver and kidneys of broiler chicks was studied. Ten-day-old male broiler chicks (Ross 308) were assigned into the control and test groups, which received normal saline and 10, 25, and 50 μg/kg CPA, respectively, for 28 days. Body weight gain, serum level of alkaline phosphatase (ALP), γ-glutamyl transferase (GGT), uric acid, creatinine, and blood urea nitrogen (BUN) were measured after 2 and 4 weeks exposure. Moreover, the total thiol molecules (TTM) and malondialdehyde (MDA) content of the liver and kidneys were assessed. No significant differences (p > 0.05) were found in body weight gain between the control and test groups. Whereas, the hepatic weight increased significantly (p < 0.05) in animals that received 25 and 50 μg/kg CPA. Both ALP and GGT level in serum were elevated in comparison to the control group. CPA also resulted in uric acid, creatinine, and BUN enhancement in broilers. The MDA content of the liver and kidneys showed remarkable increase. By contrast, the TTM levels in the liver and kidneys were significantly (p < 0.05) attenuated. Histopathological findings confirmed the biochemical changes in either organ characterized by inflammatory cells infiltration along with severe congestion and cell swelling, suggesting an inflammatory response. These data suggest that exposure to CPA resulted in hepatic and renal disorders, which were reflected as biochemical markers alteration and pathological injuries in either organ. The biochemical alteration and pathological abnormalities may be attributed to CPA-induced oxidative stress.

Effects of ochratoxin a on livestock production

Ochratoxin A (OTA) contamination often causes large economic losses on livestock production. The intake of feed contaminated by OTA also represents a potential risk for animal health and a food safety issue due to the transfer of the toxin through the food chain to humans. The aim of this paper is to review the available literature on: (1) the frequency and degree of occurrence of OTA in different feedstuffs; (2) the toxicological effects of OTA intake on the performance of the main livestock (i.e., poultry, swine, cattle, goats and sheep); and (3) the transfer of OTA, or its metabolites, from animal feed into animal products such as milk, meat and eggs.

Ochratoxins in feed, a risk for animal and human health: control strategies

Ochratoxin A (OTA) has been shown to be a potent nephrotoxic, hepatotoxic, and teratogenic compound. In farm animals, the intake of feed contaminated with OTA affects animal health and productivity, and may result in the presence of OTA in the animal products. Strategies for the control of OTA in food products require early identification and elimination of contaminated commodities from the food chain. However, current analytical protocols may fail to identify contaminated products, especially in animal feed. The present paper discusses the impact of OTA on human and animal health, with special emphasis on the potential risks of OTA residue in animal products, and control strategies applied in the feed industry.

Mycobiota and Ochratoxin A in laboratory mice feed: preliminary study

The occurrence of mycotoxin-producing moulds in animal feed is a hazard for animals. When these undesirable substances contaminate laboratory animal feed, convey an additional problem in experimental animal assays confidence levels. The aim of this study was to evaluate fungal contamination and to determine natural occurrence of Ochratoxin A (OTA) in 31 samples. OTA is a mycotoxin produced by fungi of two genera: Penicillium and Aspergillus. OTA has been shown to be nephrotoxic, hepatotoxic, teratogenic and immunotoxic to a number of animal species and to cause kidney and liver tumors in mice and rats. In this preliminary study, feed mould counts ranged from 3 to 4.2 log(10) cfu/g (colonies forming units per gram). When these species are present, there is a significant risk of contamination with mycotoxins resulting in both acute diseases called mycotoxicoses and chronic conditions, often recognized as situations involving mycotoxins. The most frequent genus isolated was Cladosporium sp. (84%), followed by Aspergillus niger and Penicillium (81%) and Mucor sp. (77%). All rat feed samples were examined for OTA, using High Performance Liquid Chromatography (HPLC). The detection limit was 2.0 microg OTA kg(-1) and all samples revealed to be negative for this mycotoxin. These mycotoxicological researches put in evidence the importance of the use contaminant-free experimental animal feed in order to prevent any interference on the health of experimental animals and emphasizes the need for systematic control of the feed as a key issue in animal experimentation.

Cyclopiazonic acid biosynthesis of Aspergillus flavus and Aspergillus oryzae

Cyclopiazonic acid (CPA) is an indole-tetramic acid neurotoxin produced by some of the same strains of A. flavus that produce aflatoxins and by some Aspergillus oryzae strains. Despite its discovery 40 years ago, few reviews of its toxicity and biosynthesis have been reported. This review examines what is currently known about the toxicity of CPA to animals and humans, both by itself or in combination with other mycotoxins. The review also discusses CPA biosynthesis and the genetic diversity of CPA production in A. flavus/oryzae populations.

Efficacy of a new ochratoxin-binding agent (OcraTox) to counteract the deleterious effects of ochratoxin A in laying hens

An experiment was conducted to evaluate the efficacy of a new ochratoxin-binding agent (Ocra-Tox, 5 g/kg of feed) in offsetting the toxic effects of ochratoxin A (OTA, 2 mg/kg of feed) in laying hen diets. Performance, serum biochemistry, OTA residue in the liver and eggs, and egg quality parameters were evaluated. Twenty-eight Hisex Brown laying hens, 47 wk of age, were allocated to 1 of 4 experimental treatments for 3 wk: control, OTA (containing 2 mg of OTA/kg of feed), OcraTox (containing 5 g of OcraTox/kg of feed), and OTA + OcraTox (containing 2 mg of OTA and 5 g of OcraTox/kg of feed). Laying hens fed OcraTox showed results similar to the control hens (P > 0.05). The OTA diet significantly (P < 0.05) reduced daily feed consumption, egg mass production, and serum triglyceride concentrations, and increased the relative liver weight, the serum activity of alkaline phosphatase, and the serum concentration of uric acid as compared with the control diet. Addition of OcraTox to the contaminated diet alleviated (P < 0.05) the negative effects resulting from OTA, reaching values not significantly different from the control diet for most of the parameters except the relative weight of the liver. Birds fed the OTA treatment showed a greater content of OTA in the liver (15.1 microg/kg) than those fed the control diet (<0.05 microg/kg). Supplementing the contaminated diet with OcraTox (OTA + OcraTox) reduced the values to 12.0 microg/kg. Residues of OTA were not detected above our detection limit (0.05 microg/kg) in any of the analyzed eggs. In conclusion, our results indicated that addition of OcraTox can counteract the deleterious effects caused by OTA in laying hens.

Impact of feed-borne mycotoxins on avian cell-mediated and humoral immune responses

Mycotoxins of economic importance in poultry production are mainly produced by Aspergillus, Penicillium and Fusarium fungi. The important mycotoxins in poultry production are aflatoxins, ochratoxins, trichothecenes, zearalenone and fumonisins. Mycotoxins exert their immunotoxic effects through various mechanisms which are manifested as reduced response of the immune system. Mycotoxin-induced immunosuppression in poultry may be manifested as decreased antibody production to antigens (e.g. sheep red blood cells) and impaired delayed hypersensitivity response (e.g. dinitrochlorobenzene), reduction in systemic bacterial clearance (e.g. Salmonella, Brucella, Listeria and Escherichia), lymphocyte proliferation (response to mitogens), macrophage phagocytotic ability, and alterations in CD4+/CD8+ ratio, immune organ weights (spleen, thymus and bursa of Fabricius), and histological changes (lymphocyte depletion, degeneration and necrosis). Mycotoxins, especially fumonisin B1 have been shown to down regulate proinflammatory cytokine levels including those of interferon (IFN)-γ, IFN-α, interleukin (IL)-1β, and IL-2 in broiler chickens. Fusarium mycotoxins exert part of their toxic effects by altering cytokine production in poultry. Mycotoxins adversely affect intestinal barrier functions by reducing the intestinal epithelial integrity and removing tight junction proteins. Apoptosis, increased colonisation of pathogenic microorganisms, cytotoxicity and oxidative stress, inhibition of protein synthesis and lipid peroxidation are characteristic of the toxic effects of mycotoxins on intestinal epithelium. These directly or indirectly affect host immune responses. Such immunotoxic effects of mycotoxins render poultry susceptible to many infectious diseases. The avian immune system is sensitive to most mycotoxins. Both cell-mediated and humoral immunity may be adversely affected after feeding mycotoxins to poultry. The avian immune system may be more sensitive to naturally contaminated feedstuffs because of the presence of multiple mycotoxins and the complex interactions between them which can cause severe adverse effects. Adverse effects of mycotoxins on the immune system reduce production and performance resulting in economic losses to poultry industries. Caution must be exercised while feeding grains contaminated with mycotoxins.

The mycobiota and toxicity of equine feeds

Feed contamination can lead to nutrient losses and detrimental effects on animal health and production. The purposes of this study were to investigate the mycobiota in equine mixed feeds and to determine natural contamination with aflatoxin B1 (AFB1) and fumonisin B1 (FB1). Fungal enumeration of equine feed samples was done. A commercially available enzyme-linked immunosorbent assay kit was applied to quantify AFB1 and FB1. A comparison between ELISA and HPLC was carried out. Feed mould counts ranged from <1 x 10(2) to 1 x 10(5) cfu/g. The most frequent genus isolated was Aspergillus (40.54%), followed by Penicillium (18.38%) and Fusarium (16.22%). The most prevalent Aspergillus sp. was A. flavus (36%). AFB1 values ranged between 0.01 and 99.4 microg/kg. FB(1) levels ranged between 0.01 and 7.49 microg/kg. HPLC and ELISA methods showed positive correlation for AFB1 and FB1 determinations (r = 0.9851 and r = 0.9791, respectively). The ELISA analytical method was efficient for AFB1 and FB1 detection. The scarcity of studies on natural fungal contamination and on the presence of AFB1 and FB1 in materials used as equine feed ingredients highlights the value and contribution of this study.

Mycoflora of poultry feeds and ochratoxin-producing ability of isolated Aspergillus and Penicillium species

In Brazil, commercial feedstuffs are an important component in modern animal husbandry, but there is no information available about fungal contamination and ochratoxin A (OTA) production. The aims of this study were to determine the mycoflora incidence in poultry feeds and evaluate OTA production. In addition, the ability to produce OTA by several Aspergillus and Penicillium species was investigated. A total of 96 samples of poultry feeds were collected from four factories in Rio de Janeiro. Samples were examined for total moulds, for Aspergillus and Penicillium spp. occurrence and for their relative densities on dichloran rose bengal chloramphenicol and dichloran 18% glycerol media. The capacity to produce ochratoxin A by selected Aspergillus and Penicillium species was determined by HPLC. Total mould counts were generally higher than 1 x 10(5 )CFU ml(-1). Aspergillus and Penicillium species were isolated in the highest numbers. Aspergillus flovus and Penicillium citrinum were the most prevalent species. There was a high percentage of potential OTA producers (46%). The amount of OTA produced on this substrate was enough to cause adverse effects in animals. Several strains isolated from poultry feeds were able to produce high levels of OTA on chloramphenicol yeast medium. OTA in raw materials needs to be surveyed and storage practices must be investigated to determine occurrence and establish the livestock toxicological risk in poultry feed.

Combined effects of selected Penicillium mycotoxins on in vitro proliferation of porcine lymphocytes

The in vitro effect of combinations of the Penicillium mycotoxins citrinin (CIT), cyclopiazonic acid (CPA), ochratoxin A (OTA), patulin (PAT), penicillic acid (PIA) and roquefortine C (RQC) on mitogen induced lymphocyte proliferation was determined using purified lymphocytes from six piglets. Dose-response curves for each mycotoxin and mycotoxin combinations were generated. The combined effects of toxin pairs based on IC20 were illustrated in isobole diagrams and statistically calculated. OTA and CIT elicited a synergistic effect. Four toxin pairs elicited additive effects, four pairs less-than-additive effects and six pairs independent effects. Thus, the majority of toxin pairs tested produced lower combined effects than an additive effect. The results indicate that the sum effect of all toxins is less than that from the summation of concentrations of the individual compounds, adjusted for differences in potencies.

Inhibition of aflatoxin B1 mutagenicity by cyclopiazonic acid in the presence of human liver preparations

Co-occurrence of cyclopiazonic acid (CPA) and aflatoxin B(1) (AFB(1)) has been reported in different food commodities. Recently, we have shown that CPA reduces AFB(1) mutagenicity in the standard Salmonella-Microsome-Assay using rat S9-mix for metabolic activation (Environ. Toxicol. Pharmacol. 11 (2002) 207). When using S9-mix prepared from individual liver fractions of human patients, CPA was found to be non-mutagenic, but exerted a significant reduction of the mutagenicity of AFB(1). Moreover, CPA was shown to inhibit testosterone hydroxylation, but not methoxyresorufin dealkylation (MROD), in human S9. Thus, the reduction of the AFB(1) mutagenicity by CPA may be attributed to the inhibitory effect of CPA on cytochrome P450 (CYP450) 3A4 activity. These findings might be of relevance to the epidemiology of food-borne mycotoxicosis as similar molar ratios to those investigated here have been reported in food commodities.

Efficacy of esterified glucomannan to counteract mycotoxicosis in naturally contaminated feed on performance and serum biochemical and hematological parameters in broilers

A study was conducted to determine the efficacy of esterified glucomannan in counteracting the toxic effects of mycotoxins in naturally contaminated diet (aflatoxin 168 ppb, ochratoxin 8.4 ppb, zearalenone 54 ppb, and T-2 toxin 32 ppb) fed to commercial broilers. One-day-old broiler chicks were randomly assigned to one of the four dietary treatments with five replicates of 14 chicks each. Four dietary treatments were 1) control; 2) esterified glucomannan, an adsorbent, tested at 0.05% of diet; 3) naturally contaminated diet; and 4) esterified glucomannan (0.05%) plus naturally contaminated diet. Body weight, feed consumption, feed efficiency, hematology, and serum biochemical and enzyme activities were evaluated. Compared with the control, the naturally contaminated diet significantly decreased body weight and feed consumption and resulted in poor feed efficiency. Esterified glucomannan effectively alleviated the growth depression caused by the naturally contaminated diet. Increased relative weights of liver and gizzard were observed in chicks fed the naturally contaminated diet. Further, feeding a naturally contaminated diet was associated with significant decreases in urea nitrogen and hematocrit values along with altered gamma-glutamyl transferase activity; however, urea nitrogen concentration was improved with addition of esterified glucomannan. These findings suggest that addition of dietary esterified glucomannan is effective in counteracting the toxic effects of naturally contaminated feed with mycotoxins.

Detection of ochratoxin A in animal feeds and capacity to produce this mycotoxin by Aspergillus section Nigri in Argentina

Ochratoxin A (OA) is a mycotoxin detected in a variety of food and feeds mostly from countries with a temperate climate because of the fungi that produce it, mainly Aspergillus ochraceus and Penicillium verrucosum. In Argentina, there is no available information about the natural occurrence of OA and ochratoxigenic fungi from feedstuffs. The aim was to evaluate the natural occurrence of OA in poultry, pig and rabbit feeds over 8 months. Likewise, the capacity to produce OA by Aspergillus section Nigri was investigated. Mycotoxin analysis showed that in some months of sampling, OA was detected in three feeds. OA was found in 38% of the poultry feed samples tested with levels ranging from 25 to 30 ng g(-1). From rabbit feed samples, 25% contained OA and the levels ranged from 18.5 to 25 ng g(-1). Only 13% of the pig feed samples were contaminated with similar levels of toxins. Ninety-four black Aspergillus strains from feedstuffs were tested for OA production. Among these, the tested species were A. niger var. niger, A. niger var. awamori, A. japonicus var. japonicus, A. japonicus var. aculeatus and A. foetidus. For the detection of OA, three methodologies were applied: the two TLC methods used for the fast screening of the filamentous fungi for the production of OA were not sensitive enough to detect OA in any of the black Aspergillus strains. When an HPLC methodology was used, the results showed that 46% of the black Aspergillus strains were producers of OA, with levels ranging from 13 to 25 ng ml(-1) culture medium. The highest percentage of ochratoxicogenic strains was isolated from rabbit feeds with 100 and 78% of A. niger var. niger and A. niger var. awamori, with mean levels of 15.5 and 14.6 ng ml(-1), respectively. From pig feeds, 61% of the A. niger var. awamori were producers of this toxin with mean levels of 16 ng ml(-1). In poultry feeds, the lowest percentage of OA producer strains was detected. The results for the occurrence of OA in feeds from different sampling months depended on storage and humidity-temperature conditions. Therefore, a good storage practice becomes very important to prevent OA production

Occurrence of aflatoxins and ochratoxin A in Indian poultry feeds

From 1998 to 2001, 216 ingredients intended for incorporation into chicken feed, which included groundnut cake, maize, millets, rice bran, sorghum, soybean, sunflower, and mixed feeds, were assayed for aflatoxins and ochratoxin A contamination using an indirect competitive enzyme-linked immunosorbent assay. Thirty-eight percent of the samples were contaminated with aflatoxins and 6% with ochratoxin A. The incidence scores of aflatoxin contamination in excess of 10 microg/kg were 41 of 95 for maize, 18 of 30 for mixed feeds, 10 of 37 for groundnut, 6 of 29 for sorghum, 5 of 10 for sunflower, 3 of 14 for rice bran, and 1 of 8 for millet. Ochratoxin A contamination, in excess of 10 microg/kg, was found in 9 of 29 sorghum samples, 1 of 27 groundnut samples, 1 of 14 rice bran samples, 1 of 10 sunflower samples, and 2 of 8 millet samples. Ochratoxin A was not found in maize and mixed feeds. None of the three soybean samples contained ochratoxin A. This is the first report, to our knowledge, of co-occurrence of aflatoxins and ochratoxin A in Indian poultry feeds. The results confirm the importance of analysis of ingredients before incorporating them into mixed feeds.

The effects of ochratoxin/aluminosilicate interaction on the tissues and humoral immune response of broilers

This study aimed to evaluate the effect of dietary ochratoxin, in the presence or absence of aluminosilicate, on the histology of the bursa of Fabricius, liver and kidneys, and on the humoral immune response of broilers vaccinated against Newcastle disease virus. The exposure of birds to 2 p.p.m. ochratoxin, in the presence or absence of aluminosilicate, reduced their humoral immune response and the number of mitotic cells in the bursa. The relative weight of the livers of the birds exposed to this toxin was increased and, microscopically, there was hepatocyte vacuolation and megalocytosis with accompanying hyperplasia of the biliary epithelium. The kidneys showed hypertrophy of the renal proximal tubular epithelium, with thickening of the glomerular basement membrane. Aluminosilicate did not ameliorate the deleterious effects of the ochratoxin.

Marked differences in the splanchnometry of farm-bred and wild red-legged partridges (Alectoris rufa L.)

Relative weights of heart, spleen, pancreas, and liver and the relative lengths of the small intestine and the cecum were taken from 40 farm-bred and 43 wild juvenile red-legged partridges (Alectoris rufa Linnaeus) in central Spain. Expressed as a ratio to head and body length, farm-bred partridges had lighter hearts (17% lighter), spleens (78%), and livers (29%) and shorter small intestines (15%) and cecae (20%), than wild birds of the same age. When expressed as a ratio to body weight, farm-bred juvenile red-legged partridges had lighter hearts (12%) and livers (23%) and shorter small intestines (9%) and cecae (12%) than wild partridges. Those differences might have been produced by diet differences (such as fiber-poor, high-energy feeds used on farms) and may affect the survival of farm-bred partridges after release.