Effects of Feeding Grains Naturally Contaminated with Fusarium Mycotoxins on Brain Regional Neurochemistry of Laying Hens, Turkey Poults, and Broiler Breeder Hens

Neurotoxic Potential of Deoxynivalenol in Murine Brain Cell Lines and Primary Hippocampal Cultures

Chronic exposure to the mycotoxin deoxynivalenol (DON) from grain-based food and feed affects human and animal health. Known consequences include entereopathogenic and immunotoxic defects; however, the neurotoxic potential of DON has only come into focus more recently due to the observation of behavioural disorders in exposed farm animals. DON can cross the blood-brain barrier and interfere with the homeostasis/functioning of the nervous system, but the underlying mechanisms of action remain elusive. Here, we have investigated the impact of DON on mouse astrocyte and microglia cell lines, as well as on primary hippocampal cultures by analysing different toxicological endpoints. We found that DON has an impact on the viability of both glial cell types, as shown by a significant decrease of metabolic activity, and a notable cytotoxic effect, which was stronger in the microglia. In astrocytes, DON caused a G1 phase arrest in the cell cycle and a decrease of cyclic-adenosine monophosphate (cAMP) levels. The pro-inflammatory cytokine tumour necrosis factor (TNF)-α was secreted in the microglia in response to DON exposure. Furthermore, the intermediate filaments of the astrocytic cytoskeleton were disturbed in primary hippocampal cultures, and the dendrite lengths of neurons were shortened. The combined results indicated DON's considerable potential to interfere with the brain cell physiology, which helps explain the observed in vivo neurotoxicological effects.

Deoxynivalenol: Mechanisms of action and its effects on various terrestrial and aquatic species

Deoxynivalenol, a type B trichothecene mycotoxin produced by Fusarium species of fungi, is a ubiquitious contaminant of cereal grains worldwide. Chronic, low dose consumption of feeds contaminated with DON is associated with a wide range of symptoms in terrestrial and aquatic species including decreased feed intake and feed refusal, reduced weight gain, and altered nutritional efficiency. Acute, high dose exposure to DON may be associated with more severe symptoms such as vomiting, diarrhea, intestinal inflammation and gastrointestinal hemorrhage. The toxicity of DON is partly related to its ability to disrupt eukaryotic protein synthesis via binding to the peptidyl transferase site of the ribosome. Moreover, DON exerts its effects at the cellular level by activating mitogen activated protein kinases (MAPK) through a process known as the ribotoxic stress response (RSR). The outcome of DON-associated MAPK activation is dose and duration dependent; acute low dose exposure results in immunostimulation characterized by the upregulation of cytokines, chemokines and other proinflammatory-related proteins, whereas longer term exposure to higher doses generally results in apoptosis, cell cycle arrest, and immunosuppression. The order of decreasing sensitivity to DON is considered to be: swine > rats > mice > poultry ≈ ruminants. However, studies conducted within the past 10 years have demonstrated that some species of fish, such as rainbow trout, are highly sensitive to DON. The aims of this review are to explore the effects of DON on terrestrial and aquatic species as well as its mechanisms of action, metabolism, and interaction with other Fusarium mycotoxins. Notably, a considerable emphasis is placed on reviewing the effects of DON on different species of fish.

Updates on the Effect of Mycotoxins on Male Reproductive Efficiency in Mammals

Mycotoxins are ubiquitous and unavoidable harmful fungal products with the ability to cause disease in both animals and humans, and are found in almost all types of foods, with a greater prevalence in hot humid environments. These mycotoxins vary greatly in structure and biochemical effects; therefore, by better understanding the toxicological and pathological aspects of mycotoxins, we can be better equipped to fight the diseases, as well as the biological and economic devastations, they induce. Multiple studies point to the association between a recent increase in male infertility and the increased occurrence of these mycotoxins in the environment. Furthermore, understanding how mycotoxins may induce an accumulation of epimutations during parental lifetimes can shed light on their implications with respect to fertility and reproductive efficiency. By acknowledging the diversity of mycotoxin molecular function and mode of action, this review aims to address the current limited knowledge on the effects of these chemicals on spermatogenesis and the various endocrine and epigenetics patterns associated with their disruptions.

Chronic Exposure to the Fusarium Mycotoxin Deoxynivalenol: Impact on Performance, Immune Organ, and Intestinal Integrity of Slow-Growing Chickens

This study investigates the long-term effects of deoxynivalenol (DON) consumption on avian growth performance, on the proliferation, apoptosis, and DNA damage of spleen cells, and on intestinal integrity. Two hundred and eight 5-day-old black-feathered Taiwan country chickens were fed diets containing 0, 2, 5, and 10 mg/kg of DON for 16 weeks. Body weight gain of male birds in the 2 mg/kg group was significantly lower than that in the 5 mg/kg group. At the end of trial, feeding DON-contaminated diets of 5 mg/kg resulted in heavier spleens. Moreover, the increase in DON induced cellular proliferation, apoptosis, and DNA damage signals in the spleen, the exception being female birds fed 10 mg/kg of DON showing reduced proliferation. Expression of claudin-5 was increased in jejunum of female birds fed 2 and 5 mg/kg of DON, whereas decreased expression levels were found in male birds. In conclusion, our results verified that DON may cause a disturbance to the immune system and alter the intestinal barrier in Taiwan country chickens, and may also lead to discrepancies in growth performances in a dose- and sex-dependent manner.

Effects of feeding deoxynivalenol (DON)-contaminated wheat to laying hens and roosters of different genetic background on the reproductive performance and health of the newly hatched chicks

A total of 216 23-week-old laying hens from two different genetic backgrounds (half of the birds were Lohmann brown [LB] and [LSL] hens, respectively) and 24 adult roosters were assigned to a feeding trial to study the effect of increasing concentrations of deoxynivalenol (DON) in the diet (0, 5, 10 mg/kg) on the reproductive performance of hens and roosters, and the health of the newly hatched chicks. Hatchability was adversely affected by the presence of DON in LB hens' diet, while the hatchability of the LSL chicks was significantly higher than LB chicks. An interaction effect between DON in the hens' diet and the breed was noticed on fertility, as the fertility was decreased in the eggs of LB hens receiving 10 mg/kg DON in their diet and increased in the eggs of LSL hens fed 10 mg/kg DON. Moreover, spleen relative weight was significantly decreased in the chicks hatched from eggs of hens fed contaminated diets, while gizzard relative weight was significantly decreased in LB chicks with 10 mg/kg DON in their diet compared with the control group. On the other hand, the chicks' haematology and organ histopathology were not affected by the dietary treatment. Additionally, the presence of DON in the roosters' diet had no effect on fertility (the percentage of fertile eggs of all laid eggs). Consequently, the current results indicate a negative impact of DON in LB hens' diet on fertility and hatchability, indicating that the breed of the hens seems to be an additional factor influencing the effect of DON on reproductive performance of the laying hens.

Multi-mycotoxin analysis in eggs using a QuEChERS-based extraction procedure and ultra-high-pressure liquid chromatography coupled to triple quadrupole mass spectrometry

A reliable and rapid method has been developed for the determination of 10 mycotoxins (beauvericin, enniatin A, A1, B1, citrinin, aflatoxin B1, B2, G1, G2 and ochratoxin A) in eggs at trace levels. Ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) has been used for the analysis of these compounds in less than 7 min. Mycotoxins have been extracted from egg samples using a QuEChERS-based extraction procedure (Quick, Easy, Cheap, Effective, Rugged and Safe) without applying any further clean-up step. Extraction, chromatographic and detection conditions were optimised in order to increase sample throughput and sensitivity. Matrix-matched calibration was used for quantification. Blank samples were fortified at 10, 25, 50 and 100 μg kg(-1), and recoveries ranged from 70% to 110%, except for ochratoxin A and aflatoxin G1 at 10 μg kg(-1), and aflatoxin G2 at 50 μg kg(-1). Relative standard deviations were lower than 25% in all the cases. Limits of detection ranged from 0.5 μg kg(-1) (for aflatoxins B1, B2 and G1) to 5 μg kg(-1) (for enniatin A, citrinin and ochratoxin A) and limits of quantification ranged from 1 μg kg(-1) (for aflatoxins B1, B2 and G1) to 10 μg kg(-1) (for enniatin A, citrinin and ochratoxin A). Seven samples were analyzed and aflatoxins B1, B2, G1, G2, and beauvericin were detected at trace levels.

Effects of feedborne fusarium mycotoxins on brain regional neurochemistry of turkeys

An experiment was conducted to investigate the effects of feeding grains naturally contaminated with Fusarium mycotoxins on brain regional neurochemistry of turkeys. The possible preventative effect of a poly-meric glucomannan mycotoxin adsorbent (GMA) was also determined. Forty-five 1-d-old male turkey poults were fed wheat-, corn-, and soybean meal-based diets up to wk 6, formulated with control grains, contaminated grains, or contaminated grains + 0.2% GMA. Deoxynivalenol was the major contaminant, and the concentrations were 2.2 and 3.3 mg/kg of feed during starter and grower phases, respectively. Concentrations of brain monoamine neurotransmitters and metabolites were measured in discrete regions of the brain including the pons, hypothalamus, and cortex by HPLC with electrochemical detection. Neurotransmitters and metabolites analyzed included norepinephrine, dopamine, 3,4-dihydroxyphenylacetic acid, serotonin (5-hydroxytryptamine, 5-HT), and 5-hydroxyindoleacetic acid (5-HIAA). The concentration of 5-HIAA and the 5-HIAA:5-HT-ratio were significantly decreased in pons after feeding contaminated grains. Dietary supplementation with GMA prevented these effects. In the pons, a significant positive correlation (r = 0.52, P < 0.05) was observed between the concentration of 5-HT and BW gain after feeding contaminated diets. The feeding of contaminated diet had no significant effects on the concentrations of neurotransmitters and metabolites in hypothalamus and cortex. It was concluded that consumption of grains naturally contaminated with Fusarium mycotoxins adversely altered the pons serotonergic system of turkeys. Supplementation with GMA partially inhibited these effects.

Pet bird toxicity and related environmental concerns

Birds may be exposed to toxins through various sources in their everyday environment. Toxicity may occur through inhalation or oral or dermal exposures. Clinicians diagnose and treat these toxicities in an effort to correct the disease of the individual patient. Recognition of toxicity in the avian patient has further significance as it relates to the patient's environment, including the health of other animals, humans, and the ecosystem. While some toxicities, such as lead and zinc toxicosis, are well-documented in avian species, others are limited to anecdotal reports and extrapolation from other species. Continued research is needed in this area of avian medicine to expand our knowledge and improve our ability to diagnose and treat toxic conditions in birds.