The metabolism of 14C aflatoxins in laying hens

The preventive effect and mechanisms of adsorbent supplementation in low concentration aflatoxin B1 contaminated diet on subclinical symptom and histological lesions of broilers

This study aimed to investigate the subclinical symptom and histological lesions of 21-day-old and 42-day-old broilers exposure to low concentration aflatoxin B1 (AFB1), and the preventive effect with adsorbent (Toxo-MX) supplementation. A total of 576 one-day-old Arbor Acres broilers were randomly allotted into 6 treatments 8 replicates and 12 birds per cage, fed with 0 ppb, 60 ppb and 120 ppb AFB1 contamination diet with or without Toxo-MX supplementation. Results showed both 60 ppb and 120 ppb AFB1 contamination significantly reduced growth performance in 21-day-old broilers (P < 0.05), but not in 42-day-old broilers (P > 0.05), however, AFB1 contamination in diet caused a higher feed to gain ratio (P < 0.05). Broilers of 21-day-old exposure to 60 ppb and 120 ppb AFB1 increased mRNA expression of hepatic inflammatory cytokines, and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity (P < 0.05), 42-day-old broilers showed a same change in 120 ppb but not in 60 ppb of AFB1 contamination (P < 0.05). mRNA expressions of clauding-1, Zonula occludens-1 (ZO-1), and occludin decreased, but Bax, Bcl-2, and caspase-3 increased in 21-day-old broilers exposure to 60 ppb and 120 ppb AFB1 (P < 0.05), broilers of 42-day-old resisted on intestinal aflatoxicosis impairment against 60 ppb AFB1 contamination (P < 0.05), but not in 120 ppb (P < 0.05). Toxo-MX supplementation significantly reversed the detrimental effects on growth performance in both age broilers and reduced the accelerated feed to gain ratio caused by AFB1 (P < 0.05). Intestinal mRNA expression of tight junction and apoptotic genes in both age broilers were recovered by Toxo-MX supplementation (P < 0.05). However, Toxo-MX did not restore the accelerated expression of hepatic inflammation cytokines and SOD, GSH-Px in 120ppb AFB1 group (P < 0.05). The data demonstrated that diet supplementation with Toxo-MX reversed the detrimental effect on growth performance and intestine in broilers exposure to 60 ppb and 120 ppb AFB1. However, did not completely recovered hepatic inflammation induced by AFB1.

Calcination Improves the In Vivo Efficacy of a Montmorillonite Clay to Bind Aflatoxin G1 in Broiler Chickens: A Toxicokinetic Approach

The goal of this study was to investigate the toxicokinetic characteristics of aflatoxin G1 (AFG1) in broiler chickens and the effect of calcination of a Tunisian montmorillonite clay on the in vivo absorption of AFG1. In this study, broiler chickens were randomly distributed into four groups of 10 animals. Group 1 was administered AFG1 (2 mg/kg body weight (BW)) by single intravenous injection (IV), group 2 received an intra-crop bolus (PO) of AFG1 without any clay, group 3 was dosed AFG1 PO together with an oral bolus of purified clay (CP), and group 4 received AFG1 PO with an oral bolus of calcined clay. A significant difference in the area under the curve (AUC_0-t) was observed for group 4 (6.78 ± 4.24 h*ng/mL) in comparison with group 2 (12.83 ± 4.19 h*ng/mL). A significant reduction of the oral bioavailability of AFG1 was observed for group 4 (7.61 ± 4.76%) compared with group 2 (14.40 ± 4.70%), while no significant effect was observed of CP. In this experiment, no phase I nor phase II metabolites of AFG1 were observed. These findings confirm that calcination of the purified montmorillonite clay enhances the adsorption of AFG1 in the gastrointestinal tract after oral administration, thereby reducing its bioavailability, thus reducing its toxic effects.

Effects on meat quality and black bone incidence of elevated dietary vitamin levels in broiler diets challenged with aflatoxin

Vitamins play an essential role in broiler nutrition. They are fundamental for normal metabolic and physiological process, and their requirements for poultry are not fixed and can be affected by multiple factors. In contrast, mycotoxins are a challenging issue because they hinder performance and the immune system. Vitamin supplementation above minimum requirements would permit improvement in productive potential, health, bone and meat quality in a situation of mycotoxin challenge. The objective of this study was to determine the influence of optimum vitamin nutrition in diets contaminated with aflatoxin in broilers from 1 to 44 days of age. A total of 1800 Cobb 500 male chicks were randomized to 15 sets of eight treatment groups, each containing 15 birds using a 2 × 2 × 2 factorial design (commercial vitamin levels and high vitamin levels, two levels of aflatoxin - 0 and 0.5 ppm with binder levels of 0 and 10 000 mg/kg). The mash diets were corn and soybean meal based, formulated according to commercial practices. Feed intake, weight gain and feed conversion were analyzed for birds from 1 to 44 days of age. To determine carcass characteristics (carcass yield, breast yield and leg yield) and black bone syndrome, two birds were slaughtered from each group at 45 days. Other analyses included breast tenderness, water loss by dripping and malonaldehyde concentrations. The results demonstrated that broilers that were fed high levels of vitamins showed better weight gain, feed conversion, carcass yield and breast yield than broilers that were fed diets with commercial vitamin levels (P < 0.05); also, broilers that were fed diets containing 0.5 ppm aflatoxin had lower weight gain, carcass yield and breast yield (P < 0.05). The use of 10 000 mg/kg of binder improved (P < 0.05) feed conversion throughout the rearing period. We conclude that aflatoxin negatively affects performance and carcass yield; however, feeding optimum vitamin nutrition improved these performance traits.

Aflatoxin B1 Contamination in Chicken Livers and Gizzards from Industrial and Small Abattoirs, Measured by ELISA Technique in Maputo, Mozambique

Aflatoxins are the most toxic and carcinogenic mycotoxins produced by Aspergillus species. Aflatoxin B1 (AFB1) contamination in industrial and local chicken livers and gizzards in Maputo was investigated. One hundred boiler livers and 80 boiler gizzards were collected from industrial and local cutting poultry production sectors. The samples were analyzed by the ELISA method (MaxSignal®, Bioo Scientific Corporation). AFB1 was found in 39% of liver samples and 13.8% of gizzards, with mean levels of 1.73 µg/kg and 1.07 µg/kg, respectively. The frequency of contamination and AFB1 levels in samples from local sector producers was not significantly higher than those from industrial sector producers (p > 0.05). No correlation was found (p = 0.493; r² = 0.013) between AFB1 levels in livers and hepatic weights. The AFB1 levels were lower than the allowed limits, suggesting that these products do not pose high risk to consumers. Notwithstanding, there is a need to implement aflatoxin residue monitoring and controls in all chicken meat products; this economic and efficient technique appears to be valuable for improved food safety in Mozambique.

Worldwide Occurrence of Mycotoxins in Cereals and Cereal-Derived Food Products: Public Health Perspectives of Their Co-occurrence

Cereal grains and their processed food products are frequently contaminated with mycotoxins. Among many, five major mycotoxins of aflatoxins, ochratoxins, fumonisins, deoxynivalenol, and zearalenone are of significant public health concern as they can cause adverse effects in humans. Being airborne or soilborne, the cosmopolitan nature of mycotoxigenic fungi contribute to the worldwide occurrence of mycotoxins. On the basis of the global occurrence data reported during the past 10 years, the incidences and maximum levels in raw cereal grains were 55% and 1642 μg/kg for aflatoxins, 29% and 1164 μg/kg for ochratoxin A, 61% and 71,121 μg/kg for fumonisins, 58% and 41,157 μg/kg, for deoxynivalenol, and 46% and 3049 μg/kg for zearalenone. The concentrations of mycotoxins tend to be lower in processed food products; the incidences varied depending on the individual mycotoxins, possibly due to the varying stability during processing and distribution of mycotoxins. It should be noted that more than one mycotoxin, produced by a single or several fungal species, may occur in various combinations in a given sample or food. Most studies reported additive or synergistic effects, suggesting that these mixtures may pose a significant threat to public health, particularly to infants and young children. Therefore, information on the co-occurrence of mycotoxins and their interactive toxicity is summarized in this paper.

Efficiency of hydrated sodium calcium aluminosilicate to ameliorate the adverse effects of graded levels of aflatoxin B1 in broiler chicks

The objective of this study was to evaluate the efficiency of a hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to ameliorate the adverse effects of 0.5 to 2 mg of aflatoxin B1 (AFB1)/kg in broiler chicks. The study consisted of 8 dietary treatments, including 4 concentrations of AFB1 (0, 0.5, 1, and 2 mg/kg) with or without HSCAS (0.5%) fed to 8 replicate cages per diet (6 males chicks per cage) from 0 to 21 d of age. Cumulative feed intake, BW gain (P < 0.0001), and G:F (P = 0.004) of birds fed the 2 mg of AFB1/kg of diet were significantly lower in comparison with birds fed 0 to 1 mg of AFB1/kg. Relative liver weight was increased in the 2 mg of AFB1/kg group (P < 0.0001). Dietary HSCAS improved cumulative BW gain (main effect P = 0.06), particularly from 14 to 21 d of age (P = 0.037). Dietary HSCAS also reversed the increase in relative liver weight for birds fed AFB1 (P = 0.019). Dietary AFB1 negatively affected major serum parameters (albumin, total protein, globulin, phosphorus, glucose, alkaline phosphatase, and creatine phosphokinase), whereas supplementation with HSCAS partially alleviated the affected serum biochemistry. In addition, serum complement activity and liver gene expression were negatively affected by 2 mg of AFB1/kg. The HSCAS supplement increased the liver expression of catalase and superoxide dismutase (P < 0.05). Results from this study indicate that dietary supplementation with HSCAS can effectively improve BW gain and partially ameliorate aflatoxicosis for broiler chicks fed AFB1-contaminated feeds.

Aflatoxin B(1) in affecting broiler's performance, immunity, and gastrointestinal tract: a review of history and contemporary issues

Aflatoxin B(1) is a common contaminant of poultry feeds in tropical and subtropical climates. Research during the last five decades has well established the negative effects of the mycotoxin on health of poultry. However, the last ten years of relevant data have accentuated the potential of low levels of aflatoxin B(1) to deteriorate broiler performance. In this regard, any attempt to establish a dose-effect relationship between aflatoxin B(1) level and broiler performance is also complicated due to differences in types of broilers and length of exposure to the mycotoxin in different studies. Contrary to the prevalent notion regarding literature saturation with respect to aflatoxicosis of chicken, many areas of aflatoxicosis still need to be explored. Literature regarding effects of the mycotoxin on the gastrointestinal tract in this regard is particular scanty and non-conclusive. In addition to these issues, the metabolism of aflatoxin B(1) and recently proposed hypotheses regarding biphasic effects of the mycotoxin in broilers are briefly discussed.

The impact of low concentrations of aflatoxin, deoxynivalenol or fumonisin in diets on growing pigs and poultry

In the present review, the quantitative impact of dietary aflatoxin, deoxynivalenol (DON) and fumonisin concentrations on performance of pigs and broilers is evaluated, with special emphasis on low concentrations of these toxins. Also, responses in performance of pigs and broilers to these three toxins are related to their absorption and elimination kinetics. By applying simple linear regression, information from many literature sources is integrated and condensed into, for example, estimates of depression in rates of weight gain, relative to non-contaminated diets, with increasing toxin concentrations. It was estimated that with each mg/kg increase of aflatoxin in the diet, the growth rate would be depressed by 16 % for pigs and 5 % for broilers. For DON, with each mg/kg increase in the diet, the growth depression was estimated at about 8 % for pigs, while broilers showed no response to DON concentrations below 16 mg/kg. Fumonisin showed the lowest impact on growth performance; with each mg/kg increase, the depression in growth rate was estimated at 0·4 and 0·0 % for pigs and broilers, respectively. Dietary concentrations that cause a 5 % reduction in growth rate were estimated at 0·3 and 1·0 mg/kg for aflatoxin for pigs and broilers, respectively; 1·8 and 0·6 mg/kg for pure and naturally contaminated DON for pigs, respectively; 21 and 251 mg/kg for fumonisin for pigs and broilers, respectively.

Occurrence of aflatoxins in layer feed and corn samples in Konya province, Turkey

The natural occurrence of aflatoxin was investigated in layer feed and corn samples brought to Konya Veterinary Control and Research Institute Laboratory between 15 April and 15 December 2002. Seventy-eight samples (52 feeds, 26 corn samples) were analysed for total aflatoxin (B1 + B2 + G1 + G2) by an ELISA screening method. Aflatoxin contamination was deter-mined in 37 feed samples (71.1%) and 15 corn samples (57.7%), with a range of 1.5-133 microg kg(-1). However, a majority of the aflatoxin contamination was less than 5 microg kg(-1) (50% within the positive samples). Two feed samples and two corn samples exceeded the maximum tolerated levels in feed (20 microg kg(-1)) and feedstuffs (50 microg kg(-1)) for total flatoxin.

Effect of cold acclimation on the broiler chicks' resistance to dietary aflatoxin

The effect of acclimation to environmental temperatures of 10 to 12 or 28 to 30 C on the resistance of broiler chicks to dietary aflatoxin was examined. Broiler chicks were acclimated from day-of-age for 2 wk to environmental temperatures of 10 to 12 or 28 to 30 C. On Day 14, a single oral dose of aflatoxin (8 mg per kg of body weight) was administered to 50 chicks in each environment. An increase in aflatoxin resistance, as assessed by survival rate, was conveyed by acclimation to cold temperatures. In each environmental chamber, a separate group of chicks was maintained for 2 additional wk, but those groups received 5 mg of aflatoxin per kg feed. By the end of the study, aflatoxicosis was characterized by: 1) a significant (P less than or equal to .05) decrease in body weight; 2) increases in spleen weight, liver weight, liver lipid, and liver dry-matter content; 3) changes in the serum levels of total protein, albumin, glucose, cholesterol, uric acid, potassium, phosphorus, iron and calcium; and 4) increased hepatic hyperplasia. Acclimation to 10 to 12 C was characterized by: 1) an increase in body weight, liver weight, spleen weight and bursa weight; 2) changes in the serum glucose and potassium levels; and 3) a decrease in glutamic-oxaloacetic transaminase activity. Significant aflatoxin by temperature interactions were evident only in serum levels of glucose and phosphorus, and in the serum activity of glutamic-oxaloacetic transaminase. These data suggest that acclimation to cool temperatures does not play a significant role in the resistance by broiler chickens to chronic aflatoxin exposure.

Aflatoxin carryover and clearance from tissues of laying hens

A feeding trial was conducted to determine the levels of aflatoxins deposited in the tissues of hens fed a diet contaminated with 3310 micrograms AFB1/kg and 1680 micrograms AFB2/kg for 4 wk. At the end of aflatoxin feeding, the livers were pale, enlarged and haemorrhagic and the ovaries were significantly smaller than those from control hens and contained only small ova. Only a small fraction of the aflatoxins consumed was deposited in the tissues, either as the original compounds or as their metabolites, which were widely distributed in all tissues. The highest levels of aflatoxins were detected in the gizzard, kidneys and liver, with average total concentrations of less than 3 micrograms/kg. The lowest residue levels were detected in the breast, blood serum and leg, with breast muscle having a total concentration of less than 0.1 microgram/kg. Two days after removal of the contaminated feed, aflatoxin residues in all tissues had decreased markedly, with no aflatoxins being detected in the heart or spleen. No aflatoxin residues were detected in the breast, leg, gizzard and ovaries of hens killed 8 days after withdrawal, or in the kidneys and blood at 16 days. However, one of seven hens had measurable amounts of AFB2 in the liver 32 days after withdrawal. Although few residues were detected in most tissues after 8 days on the aflatoxin-free diet, variation existed between tissues and between individual hens in the amount of time required to achieve tissue clearance.

Metabolite distribution and rate of residue clearance in turkeys fed a diet containing aflatoxin B1

The retention of aflatoxin residues in tissues of turkey poults fed a diet containing aflatoxin B1 (500 ppb) for 18 days was determined. Free and conjugated aflatoxin metabolites were quantified using high-pressure liquid chromatography. Aflatoxin residue levels were greater in liver than muscle tissues, although all levels were low (range 0.01-1.19 ng/g tissue). Free and conjugated aflatoxins B1 and M1, a metabolite of B1, were the principal tissue residues. Other metabolites investigated included aflatoxicol, which was detected in certain samples, and aflatoxin Q1 which was not detected. Conjugated aflatoxins, hydrolysed and extracted from the aqueous tissue fractions, comprised 55-91% of the total detected aflatoxin residues. All aflatoxin residues were rapidly cleared following discontinuation of the dietary aflatoxin B1 (half-life 1.4 days for total aflatoxin clearance from liver). These results provide further evidence that tissues from animals maintained on diets containing aflatoxins do not provide a major source of aflatoxins when consumed by man.