Reversal of toxigenic effects of aflatoxin B1 on cockerels by alcoholic extract of African nutmeg,Monodora myristica

The reversal of the toxigenic effects of crystalline aflatoxin B₁ (AFB₁; from Aspergilus flavus) on cockerels using different concentrations of the ethanolic extract from the seeds of African nutmeg, Monodora myristica, was studied in 130 two‐week‐old cockerels, randomly divided into 13 groups (A–M) of ten birds each. Group A (controls) received 100 µl of phosphate‐buffered saline, while those in the test groups B, C and D received 690 ng, 1380 ng or 2010 ng of AFB₁, respectively; groups E to M received the three doses of AFB₁ with either 0.1, 0.2 or 0.3 ml of the extract of M myristica, respectively, 5 min after administration of AFB₁. Jugular blood, collected on days 14 and 21 after administration, was analysed for haematology parameters, serum proteins, alanine aminotransaminase (ALT), aspartate aminotransaminase (AST) and γ‐glutamyl transferase (GGT) levels. The birds were observed daily for clinical signs and mortality for 21 days. Post‐mortem examination was carried out on the livers of dead birds and those sacrificed by exsanguination after the 21 days post‐administration. One hundred per cent mortality was recorded in cockerels that received high doses of only AFB₁ within 72 h (2010 ng per bird), and between 17 and 19 days (1380 ng). The cockerels developed leucocytosis and microcytic hypochromic anaemia. Dosing with 0.2 or 0.3 ml of the extract of M myristica reversed these changes over time, while the lowest dose (0.1 ml) did not. While serum bilirubin levels rose significantly in test cockerels, no significant changes (P > 0.05) were observed in the levels of serum proteins of control and test cockerels, whether or not they received the extract of M myristica. Aflatoxicosis caused significant decreases and increases (P < 0.05) in serum AST and GGT levels, respectively, while the administration of alcoholic extract of M myristica reversed the GGT but not AST levels to normal. Livers from control cockerels and those given 2010 ng of AFB₁ showed no appreciable gross or histological lesions. The other groups showed mild to moderate hepatomegaly, paleness and friability, diffuse vacuolar degeneration and necrosis, Kupffer cell proliferation, presence of megalocytes and multinucleated hepatocytes. Cockerels that received 0.2 or 0.3 ml of extract of M myristica, irrespective of the dose of AFB₁ showed the mildest hepatic lesions. The results of this study show that AFB₁ is highly toxigenic to cockerels and that this could be successfully reversed by the concurrent administration of alcoholic extract of M myristica. It is therefore recommended that reduction of fungal growth on foods and subsequent toxicosis by aeration, cooling, modified atmospheres or by fungistats, is complemented with the use of extracts of spices from M myristica seed, a tree widely distributed along the west coast and central Africa. Copyright © 2004 Society of Chemical Industry     

Growth performance,digestibility, and plasma metabolomic profiles of Saanen goats exposed to different doses of aflatoxin B1

Aflatoxin contamination of feed poses a great risk to the global dairy industry. Analyzing the aflatoxin B₁ (AFB₁)-induced metabonomic changes in ruminants and screening potential biomarkers for early diagnosis of AFB₁ exposure is urgently needed. Here, the effects of different doses (0, 50, and 500 μg/kg of the diet, dry matter basis) of AFB₁ exposure on digestibility and performance of Saanen goats were studied, and a comprehensive untargeted metabolomic analysis was performed to reveal plasma metabonomic changes caused by the AFB₁ exposure. In the current study, AFB₁ exposure decreased total-tract nutrient digestibilities, nitrogen retention, total weight gain, and average daily gain of Saanen goats in a dose-dependent manner. Untargeted metabolomics revealed alterations in the plasma metabolome. A total of 3,310 and 1,462 ion peaks were obtained in positive and negative ion modes, respectively. Based on the screening criteria, 1,338 differential metabolites were detected between control and low-dose AFB₁ (50 μg/kg) groups, 1,358 metabolites differed between control and high-dose AFB₁ (500 μg/kg) groups, and 58 metabolites differed among all groups. Pathway analyses showed that choline metabolism in cancer and glycerophospholipid metabolism were significantly affected by the AFB₁ treatments. Moreover, dysregulation of amino acid metabolism was also observed in AFB₁ treated goats. The findings provided novel insights into the toxicity of AFB₁ in ruminants. Exploring the underlying molecular causes of the changes may help the development of rapid diagnostic techniques and effective interventions for AFB₁ intoxication.     

NovaSil clay intervention in Ghanaians at high risk for aflatoxicosis: II. Reduction in biomarkers of aflatoxin exposure in blood and urine

The efficacy of NovaSil clay (NS) to reduce aflatoxin (AF) biomarkers of exposure was evaluated in 656 blood samples and 624 urine samples collected from study participants during a 3-month phase IIa clinical intervention trial in Ghana. NS was delivered before meals via capsules. Serum AFB₁–albumin adduct was measured by radioimmunoassay and urinary AFM₁ metabolites were quantified by immunoaffinity-high-performance liquid chromatography (HPLC)-fluorescence methods. Levels of AFB₁–albumin adduct in serum samples collected at baseline and at 1 month were similar (p?=?0.2354 and p?=?0.3645, respectively) among the placebo (PL), low dose (LD, 1.5 g NS day^?1), and high dose (HD, 3.0 g NS day^?1) groups. However, the levels of AFB₁–albumin adduct at 3 months were significantly decreased in both the LD group (p?<?0.0001) and the HD group (p?<?0.0001) compared with levels in the PL group. Levels of AFM₁ in urine samples collected at baseline and at 1 month were not statistically different among the three study groups. However, a significant decrease (up to 58%) in the median level of AFM₁ in samples collected at 3 months was found in the HD group when compared with the median level in the PL group (p?<?0.0391). In addition, significant effects were found for dose, time, and dose–time interaction with serum AFB₁–albumin adduct and dose–time interaction with urinary AFM₁ metabolites. The results suggest that capsules containing NS clay can be used to reduce effectively the bioavailability of dietary AF based on a reduction of AF-specific biomarkers.     

Effect of dietary macronutrients on aflatoxicosis: a mini‐review

Aflatoxin is a toxin produced by Aspergillus species of fungi. The main route of aflatoxin exposure is through the diet. Indeed, long‐term aflatoxin exposure is linked to the development of hepatocellular carcinoma (HCC). Aflatoxin causes aflatoxicosis, which can be affected by several factors and is prevalent in many developing Asian and African countries. This mini‐review discusses the effects of carbohydrate, fat and protein on aflatoxicosis based on findings from animal and human studies. It was found that high carbohydrate intake enhanced aflatoxicosis occurrence, while low ingestion of carbohydrate with caloric restriction slowed the symptoms associated with aflatoxicosis. Additionally, diets with low protein content worsened the symptoms related to HCC due to aflatoxin exposure. Nevertheless, a study reported that a high‐protein diet favored detoxification of aflatoxin in vivo. There were also conflicting results on the influence of dietary fat, as high ingestion of fat enhanced aflatoxicosis development as compared with a low‐fat diet. Moreover, the type of fat also plays a significant role in influencing aflatoxin toxicity. In regard to food safety, understanding the influence of macronutrients toward the progression of aflatoxicosis can improve preventive measures against human and animal exposure to aflatoxin. © 2017 Society of Chemical Industry     

Impact of mycotoxins on human health in developing countries

Adverse human health effects from the consumption of mycotoxins have occurred for many centuries. Although mycotoxin contamination of agricultural products still occurs in the developed world, the application of modern agricultural practices and the presence of a legislatively regulated food processing and marketing system have greatly reduced mycotoxin exposure in these populations. At the mycotoxin contamination levels generally found in food products traded in these market economies, adverse human health effects have largely been overcome. However, in the developing world, where climatic and crop storage conditions are frequently conducive to fungal growth and mycotoxin production, much of the population relies on subsistence farming or on unregulated local markets. The extent to which mycotoxins affect human health is difficult to investigate in countries whose health systems lack capacity and in which resources are limited. Aflatoxin B₁, the toxin on which major resources have been expended, has long been linked to liver cancer, yet its other effects, such as immune suppression and growth faltering previously observed in veterinary studies, are only now being investigated and characterized in human populations. The extent to which factors such as immune suppression contribute to the overall burden of infectious disease is difficult to quantify, but is undoubtedly significant. Thus, food safety remains an important opportunity for addressing current health problems in developing countries.