Feeding a diet contaminated with ochratoxin A for broiler chickens at the maximum level recommended by the EU for poultry feeds (0.1 mg/kg). 2. Effects on meat quality, oxidative stress, residues and histological traits

Risks for animal health related to the presence of ochratoxin A (OTA) in feed

In 2004, the EFSA Panel on Contaminants in the Food Chain (CONTAM) adopted a Scientific Opinion on the risks to animal health and transfer from feed to food of animal origin related to the presence of ochratoxin A (OTA) in feed. The European Commission requested EFSA to assess newly available scientific information and to update the 2004 Scientific Opinion. OTA is produced by several fungi of the genera Aspergillus and Penicillium. In most animal species it is rapidly and extensively absorbed in the gastro-intestinal tract, binds strongly to plasma albumins and is mainly detoxified to ochratoxin alpha (OTalpha) by ruminal microbiota. In pigs, OTA has been found mainly in liver and kidney. Transfer of OTA from feed to milk in ruminants and donkeys as well as to eggs from poultry is confirmed but low. Overall, OTA impairs function and structure of kidneys and liver, causes immunosuppression and affects the zootechnical performance (e.g. body weight gain, feed/gain ratio, etc.), with monogastric species being more susceptible than ruminants because of limited detoxification to OTalpha. The CONTAM Panel considered as reference point (RP) for adverse animal health effects: for pigs and rabbits 0.01 mg OTA/kg feed, for chickens for fattening and hens 0.03 mg OTA/kg feed. A total of 9,184 analytical results on OTA in feed, expressed in dry matter, were available. Dietary exposure was assessed using different scenarios based on either model diets or compound feed (complete feed or complementary feed plus forage). Risk characterisation was made for the animals for which an RP could be identified. The CONTAM Panel considers that the risk related to OTA in feed for adverse health effects for pigs, chickens for fattening, hens and rabbits is low.

Underreported Human Exposure to Mycotoxins: The Case of South Africa

South Africa (SA) is a leading exporter of maize in Africa. The commercial maize farming sector contributes to about 85% of the overall maize produced. More than 33% of South Africa’s population live in rural settlements, and their livelihoods depend entirely on subsistence farming. The subsistence farming system promotes fungal growth and mycotoxin production. This review aims to investigate the exposure levels of the rural population of South Africa to dietary mycotoxins contrary to several reports issued concerning the safety of South African maize. A systematic search was conducted using Google Scholar. Maize is a staple food in South Africa and consumption rates in rural and urban communities are different, for instance, intake may be 1–2 kg/person/day and 400 g/person/day, respectively. Commercial and subsistence maize farming techniques are different. There exist differences influencing the composition of mycotoxins in food commodities from both sectors. Depending on the levels of contamination, dietary exposure of South Africans to mycotoxins is evident in the high levels of fumonisins (FBs) that have been detected in SA home-grown maize. Other potential sources of exposure to mycotoxins, such as carryover effects from animal products and processed foods, were reviewed. The combined effects between FBs and aflatoxins (AFs) have been reported in humans/animals and should not be ignored, as sporadic breakouts of aflatoxicosis have been reported in South Africa. These reports are not a true representation of the entire country as reports from the subsistence-farming rural communities show high incidence of maize contaminated with both AFs and FBs. While commercial farmers and exporters have all the resources needed to perform laboratory analyses of maize products, the greater challenge in combatting mycotoxin exposure is encountered in rural communities with predominantly subsistence farming systems, where conventional food surveillance is lacking.

A Newly Isolated Alcaligenes faecalis ANSA176 with the Capability of Alleviating Immune Injury and Inflammation through Efficiently Degrading Ochratoxin A

Ochratoxin A (OTA) is one of the most prevalent mycotoxins that threatens food and feed safety. Biodegradation of OTA has gained much attention. In this study, an Alcaligenes faecalis strain named ANSA176, with a strong OTA-detoxifying ability, was isolated from donkey intestinal chyme and characterized. The strain ANSA176 could degrade 97.43% of 1 mg/mL OTA into OTα within 12 h, at 37 °C. The optimal levels for bacterial growth were 22–37 °C and pH 6.0–9.0. The effects of ANSA176 on laying hens with an OTA-contaminated diet were further investigated. A total of 36 laying hens were assigned to three dietary treatments: control group, OTA (250 µg/kg) group, and OTA + ANSA176 (6.2 × 10⁸ CFU/kg diet) group. The results showed that OTA decreased the average daily feed intake (ADFI) and egg weight (EW); meanwhile, it increased serum alanine aminopeptidase (AAP), leucine aminopeptidase (LAP), β2-microglobulin (β2-MG), immunoglobulin G (IgG), tumor necrosis factor-α (TNF-α), and glutathione reductase (GR). However, the ANSA176 supplementation inhibited or attenuated the OTA-induced damages. Taken together, OTA-degrading strain A. faecalis ANSA176 was able to alleviate the immune injury and inflammation induced by OTA.

Multi-mycotoxin occurrence in feed, metabolism and carry-over to animal-derived food products: A review

The world requests for raw materials used in animal feed has been steadily rising in the last years driven by higher demands for livestock production. Mycotoxins are frequent toxic metabolites present in these raw materials. The exposure of farm animals to mycotoxins could result in undesirable residues in animal-derived food products. Thus, the potential ingestion of edible animal products (milk, meat and fish) contaminated with mycotoxins constitutes a public health concern, since they enter the food chain and may cause adverse effects upon human health. The present review summarizes the state-of-the-art on the occurrence of mycotoxins in feed, their metabolism and carry-over into animal source foodstuffs, focusing particularly on the last decade. Maximum levels (MLs) for various mycotoxins have been established for a number of raw feed materials and animal food products. Such values are sometimes exceeded, however. Aflatoxins (AFs), fumonisins (FBs), ochratoxin A (OTA), trichothecenes (TCs) and zearalenone (ZEN) are the most prevalent mycotoxins in animal feed, with aflatoxin M₁ (AFM1) predominating in milk and dairy products, and OTA in meat by-products. The co-occurrence of mycotoxins in feed raw materials tends to be the rule rather than the exception, and the carry-over of mycotoxins from feed to animal source foods is more than proven.

Effect of a Mycotoxin Binder (MMDA) on the Growth Performance, Blood and Carcass Characteristics of Broilers Fed Ochratoxin A and T-2 Mycotoxin Contaminated Diets

Simple Summary

The contamination of feed with mycotoxins is a global concern, resulting in adverse effects on productivity and animal health and, therefore, a great economic loss. Ochratoxin A and T-2 mycotoxins are among the mycotoxins that contaminate animal feed. These mycotoxins could adversely affect the health of broilers, and the most effective method to mitigate the toxic effects of mycotoxins is the use of detoxifying agents. In the present experiment, broiler chickens were allotted into five groups. Group 1 received a non-contaminated diet; group 2 received a non-contaminated diet + 3 g/kg of a mycotoxin binder (MMDA); group 3 received a non-contaminated diet + 0.5 mg/kg OTA + 1 mg/kg T-2 toxin; group 4 received a non-contaminated diet + 0.5 mg/kg OTA + 1 mg/kg T-2 toxin + 1 g/kg MMDA; and group 5 received a non-contaminated diet + 0.5 mg/kg OTA + 1 mg/kg T-2 toxin + 3 g/kg MMDA for 35 days. The results revealed that OTA and T-2 toxin negatively affected the productive parameters and some blood and carcass characteristics of broiler chickens. The addition of the detoxifying agent (MMDA at 1 or 3 g/kg feed) to contaminated diets alleviated the adverse effects observed on productivity and the broilers heath related parameters.

Abstract

The present study was conducted to evaluate the efficacy of the feed additive, a novel multicomponent mycotoxin detoxifying agent (MMDA) containing modified zeolite (clinoptilolite), Bacillus subtilis, B. licheniformis, Saccharomyces cerevisiae cell walls, and silymarin, as detoxifiers of 0.5 mg/kg (0.5 ppm) ochratoxin A (OTA) and 1 mg/kg (1 ppm) T-2 toxin on broiler chickens. A total of 240 1-old broiler chickens (Ross 308) were randomly distributed into five different dietary treatments: (1) control (non-contaminated diet); (2) non contaminated diet + 3 g/kg of MMDA; (3) non-contaminated diet + 0.5 mg/kg OTA + 1 mg/kg T-2 toxin; (4) non-contaminated diet + 0.5 mg/kg OTA + 1 mg/kg T-2 toxin + 1 g/kg MMDA; and (5) non-contaminated diet + 0.5 mg/kg OTA + 1 g/kg T-2 toxin + 3 g/kg MMDA. The results showed that, in the starter period, from 1 to 10 days, the presence of OTA and T-2 mycotoxins reduced the consumption of feed and the growth of the broilers, and no effects of the detoxifying product were observed in the productivity of the chickens, at any of the doses tested, compared to the contaminated control (treatment 3). However, in the growing period, the same negative effect of mycotoxins was registered, but a recovery was observed in the consumption of feed and in the weight of the broilers that consumed 3 g/kg of the MMDA mycotoxin binder, reaching similar values to those of chickens fed uncontaminated control diets. The presence of mycotoxins in feed led to a reduction in the concentration of total proteins and albumin in blood compared to controls, and the presence of the detoxifying product partially reversed this effect. The breast yield of the chickens fed with mycotoxins was lower than that of the animals fed with the control feed and was not affected by the presence of the product tested, at 1 or 3 g/kg. The weight of the different organs (liver, gizzard, kidneys, or spleen), the intestinal pH, the histology of the small intestine, and oral lesions were not affected by the experimental treatments. In summary, the productive parameters and some blood and carcass characteristics of broiler chickens were impaired by the dietary presence of OTA and T-2 toxin. The tested product included at 1 or 3 g/kg feed in contaminated diets improved performance and seems to be effective in partly counteracting the deleterious effects of the tested mycotoxins.

Role of the glutathione redox system in the susceptibility of pheasants (Phasianus colchicus) to ochratoxin A

The purpose of the present study was to investigate the effects of different dietary concentrations of ochratoxin A (OTA) on the growth, feed intake, mortality, blood plasma protein content and some parameters of lipid peroxidation and the glutathione redox system of pheasant chicks in a three-week long trial. A total of 320 seven-day-old female pheasants were randomly assigned to four treatment groups (n = 40 in each), fed with a diet artificially contaminated with OTA [control (<0.02 mg/kg), 0.88 mg/kg, 1.14 mg/kg and 1.51 mg/kg] for 21 days (up to 28 days of age). The pheasant chicks were sacrificed at early (12, 24 and 72 h) and late (7, 14 and 21 days) stages of mycotoxin exposure to check the effect of OTA. Minimal feed refusal was found in the medium- and high-dose toxin groups (-9.8 and -7.9%, respectively), and body weight gain was nearly the same in all groups. The glutathione redox system was activated mainly in the liver, confirmed by significantly increased reduced glutathione content and glutathione peroxidase activity during the late phase of mycotoxin exposure and at a high-dose treatment. The results suggest that pheasants have low susceptibility to OTA, and activation of the glutathione redox system has importance in this tolerance.

Susceptibility of Broiler Chickens to Deoxynivalenol Exposure via Artificial or Natural Dietary Contamination

Simple Summary

This study evaluated the effect of diets artificially or naturally contaminated with 4000 μg/kg deoxyvalenol (DON) on the intestinal integrity and nutrient absorption of broiler chickens. Young broiler chickens (14 days old) were more sensitive to DON than older birds (28 days old), and negative impacts were observed when diets were naturally contaminated with DON. Aside from the decrease in the villus height of the jejunum in young broilers, their capacity to absorb peptides was decreased, as shown by the down-regulation of a peptide transporter. However, this effect was compensated in older broilers by an increase in the expression of carbohydrate transporter.

Abstract

Multi-mycotoxin contamination of poultry diets is a recurrent problem, even if the mycotoxins levels are below EU recommendations. Deoxynivalenol (DON) is one of the main studied mycotoxins due to its risks to animal production and health. When evaluating the effects of DON, one must consider that under practical conditions diets will not be contaminated solely with this mycotoxin. In the present study, broiler chickens were fed diets with negligible mycotoxin levels or with naturally or artificially contaminated diets containing approximately 4000 μg/kg DON. Birds were sampled at D14 and D28. Naturally-contaminated diets caused the most harm to the birds, especially the young ones, which presented decreased jejunal villus height and increased lesions, down-regulation of a peptide transporter. At D28 broiler chickens seemed to have adapted to the dietary conditions, when no differences were observed in villus morphometry, together with up-regulation of a carbohydrate transporter. However, intestinal lesions remained present in these older birds.

Effects of a modified clinoptilolite zeolite on growth performance, health status and detoxification of aflatoxin B1 and ochratoxin A in male broiler chickens

1. The aim of the present study was to test the ability of an in-feed modified clinoptilolite zeolite-based mycotoxin binding substance (Minazel® Plus, Patent Co, Misicevo, Serbia; MP) to prevent gastrointestinal absorption of aflatoxin B₁ (AFB1) and ochratoxin A (OTA) and its effects on health status and performance parameters of broilers.2. A total of 375, 1 d old male broiler chickens (Cobb 500) were used for a total trial period of 42 d (from hatch to 42 d of age). Animals were randomly allocated to five treatment groups (T1-T5), in 25 pens (15 male broilers per pen, five pens per treatment). T1 was the control maize-based diet without the addition of mycotoxins, or the test product. T2 and T3 groups received contaminated maize in the diet containing 0.02 mg AFB1/kg feed and 0.1 mg OTA/kg feed, whereas T4 and T5 groups received 0.05 mg AFB1/kg feed and 0.5 mg OTA/kg feed. The MP was added to T3 (1 g/kg feed), and T5 (2 g/kg feed) groups.3. Results showed that exposure to AFB1 and OTA at low or moderate levels, as used in this study, did not markedly affect growth performance, blood profile or organ weights. Improvements in feed conversion ratio (FCR) were observed in birds receiving MP, whereby FCR of T3 group was improved in comparison with T2 group, although there was no significant difference between T5 and T4 groups. However, average body weight gain (ABWG) was improved in the T5 group compared to T4, but not in the T3 versus T2 group comparison.4. For serum biochemical parameters, glutamate-dehydrogenase (GLDH) was significantly improved in T5 birds in comparison with T4. The addition of MP significantly decreased residue levels of AFB1 in liver and OTA in the spleen of the treated groups.5. The improvements in productive performance and reduction of mycotoxin residue levels in tissues demonstrated a beneficial effect of MP in cases of concurrent AFB1 and OTA ingestion by broilers.

A Study of Carry-Over and Histopathological Effects after Chronic Dietary Intake of Citrinin in Pigs, Broiler Chickens and Laying Hens

Citrinin (CIT) is a polyketide mycotoxin occurring in a variety of food and feedstuff, among which cereal grains are the most important contaminated source. Pigs and poultry are important livestock animals frequently exposed to mycotoxins, including CIT. Concerns are rising related to the toxic, and especially the potential nephrotoxic, properties of CIT. The purpose of this study was to clarify the histopathological effects on kidneys, liver, jejunum and duodenum of pigs, broiler chickens and laying hens receiving CIT contaminated feed. During 3 weeks, pigs (n = 16) were exposed to feed containing 1 mg CIT/kg feed or to control feed (n = 4), while 2 groups of broiler chickens and laying hens (n = 8 per group) received 0.1 mg CIT/kg feed (lower dose group) and 3 or 3.5 mg CIT/kg feed (higher dose group), respectively, or control feed (n = 4). CIT concentrations were quantified in plasma, kidneys, liver, muscle and eggs using a validated ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. Kidneys, liver, duodenum and jejunum were evaluated histologically using light microscopy, while the kidneys were further examined using transmission electron microscopy (TEM). Histopathology did not reveal major abnormalities at the given contamination levels. However, a significant increase of swollen and degenerated mitochondria in renal cortical cells from all test groups were observed (p < 0.05). These observations could be related to oxidative stress, which is the major mechanism of CIT toxicity. Residues of CIT were detected in all collected tissues, except for muscle and egg white from layers in the lowest dose group, and egg white from layers in the highest dose group. CIT concentrations in plasma ranged between 0.1 (laying hens in lower dose group) and 20.8 ng/mL (pigs). In tissues, CIT concentrations ranged from 0.6 (muscle) to 20.3 µg/kg (liver) in pigs, while concentrations in chickens ranged from 0.1 (muscle) to 70.2 µg/kg (liver). Carry-over ratios from feed to edible tissues were between 0.1 and 2% in pigs, and between 0.1 and 6.9% in chickens, suggesting a low contribution of pig and poultry tissue-derived products towards the total dietary CIT intake for humans.

The Effect of Using New Synbiotics on the Turkey Performance, the Intestinal Microbiota and the Fecal Enzymes Activity in Turkeys Fed Ochratoxin A Contaminated Feed

The feed supplementation of probiotic microorganisms is a promising method for detoxification of ochratoxin A (OTA) in poultry. The aim of the study was to investigate the effect of newly elaborated synbiotics on the turkey performance, the intestinal microbiota and its enzymatic activity in turkeys (0-15 weeks) fed OTA contaminated feed (198.6-462.0 µg/kg) compared to control group (OTA-free feed). The studies determined the composition of intestinal microorganisms by the culture method and the activity of fecal enzymes by spectrophotometry. It was found that OTA had an adverse effect on the body weight, the intestinal microbiota and the fecal enzymes activity in turkeys. On the other hand, synbiotics resulted in an increase in the count of beneficial bacteria while reducing the number of potential pathogens in the digestive tract. Moreover, synbiotics caused an increase in the activity of α-glucosidase and α-galactosidase, while decreasing the activity of potentially harmful fecal enzymes (β-glucosidase, β-galactosidase, β-glucuronidase) in the turkey's excreta. Results indicate a beneficial effect of elaborated synbiotics on the health of turkeys and a reduction of the negative impact of OTA contaminated feed. These synbiotics can be successfully used as feed additives for turkeys.

Comprehensive Evaluation of the Efficiency of Yeast Cell Wall Extract to Adsorb Ochratoxin A and Mitigate Accumulation of the Toxin in Broiler Chickens

Ochratoxin A (OTA) is a common mycotoxin contaminant in animal feed. When absorbed from the gastrointestinal tract, OTA has a propensity for pathological effects on animal health and deposition in animal tissues. In this study, the potential of yeast cell wall extracts (YCWE) to adsorb OTA was evaluated using an in vitro method in which consecutive animal digestion events were simulated. Low pH markedly increased OTA binding to YCWE, which was reversed with a pH increased to 6.5. Overall, in vitro analysis revealed that 30% of OTA was adsorbed to YCWE. Additional computational molecular modelling revealed that change in pH alters the OTA charge and modulates the interaction with the YCWE β-d-glucans. The effectiveness of YCWE was tested in a 14-day broiler chicken trial. Birds were subjected to five dietary treatments; with and without OTA, and OTA combined with YCWE at three dosages. At the end of the trial, liver OTA deposition was evaluated. Data showed a decrease of up to 30% in OTA deposits in the liver of broilers fed both OTA and YCWE. In the case of OTA, a tight correlation between the mitigation efficacy of YCWE between in vitro and in vivo model could be observed.

Bush sophora root polysaccharide could help prevent aflatoxin B1-induced hepatotoxicity in the primary chicken hepatocytes

The aim of this study was to evaluate the effects of bush sophora root polysaccharide (BSRPS) on the aflatoxin B1 (AFB1)-induced hepatotoxicity and to explore the underlying mechanisms. The primary chicken hepatocytes were used as the model in the present experiment. The results showed that AFB1 induced hepatotoxicity of chicken hepatocytes in a dose dependent manner as demonstrated by decreasing cell viability and increasing LDH activity, ALT and AST levels. AFB1 at 0.16 μM significantly increased the levels of hepatic cytochrome P450 1A5 (CYP450 1A5) mRNA and malondialdehyde (MDA) and decreased the activity and mRNA level of manganese superoxide dismutase(SOD2) and the glutathione peroxidases (GSH-Px) activity in the hepatocytes compared with the blank control. BSRPS at 8.93 μM, 17.86 μM, and 35.72 μM supplementation could significantly reverse the above-mentioned changes induced by AFB1, and 17.86 μM of BSRPS has the largest effects on protecting the AFB1-induced hepatocytes damage. Knock-down of SOD2 by SOD2-specific siRNA significantly eliminated the protective effects of BSRPS on AFB1-induced the increase of CYP450 1A5 mRNA levels and hepatotoxicity. These results suggested that the BSRPS has protective effects on AFB1-induced hepatotoxicity by down-regulating CYP450 1A5 mRNA level via up-regulating SOD2 expression in the primary chicken hepatocytes.

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.

Feeding a diet contaminated with ochratoxin A for chickens at the maximum level recommended by the EU for poultry feeds (0.1 mg/kg). 1. Effects on growth and slaughter performance, haematological and serum traits

The European Commission Recommendation 2006/576/EC, suggests that the maximum level of Ochratoxin A (OTA) in poultry feeds should be set at 0.1 mg OTA/kg. Thirty-six one-day-old male Hubburd broiler chickens were divided into two groups, a Control (basal diet) and an Ochratoxin A (basal diet + 0.1 mg OTA/kg) group. The growth and slaughter performance traits were recorded. The liver, spleen, bursa of Fabricius and thymus weights were measured. The erythrocyte and leukocyte numbers were assayed in blood samples, and the heterophils to lymphocytes (H/L) ratio was determined. Alpha-1-acid glycoprotein (AGP), lysozyme, the total protein and the electrophoretic pattern were evaluated in serum samples. Liver enzymes (alanino aminotransferase, ALT and aspartate aminotransferase, AST) and kidney function parameters (uric acid and creatinine) were quantified. The results revealed that feeding a 0.1 mg OTA/kg contaminated diet to chicks caused a decrease in the absolute thymus weight (p < 0.05) and a lower total protein (p < 0.01), albumin (p < 0.01), alpha (p < 0.05), beta (p = 0.001) and gamma (p = 0.001) globulins serum concentration in the Ochratoxin A group. Moreover, the albumin-to-globulin (A/G) ratio of the OTA-treated animals resulted to be higher (p < 0.05). Feeding broiler chickens, a diet contaminated with the maximum level admitted by the European Commission Recommendation (0.1 mg OTA/kg), did not affect the animal performance, slaughter traits, organ weights, haematological parameters, liver enzyme or renal function parameters concentrations but had an overall immunosuppressant effect, with reduction in the thymus weight and of the total serum protein, albumin, alpha, beta and gamma globulins concentration.