INTRODUCTION
Mycotoxins are toxic secondary metabolites of moulds and their negative effects on poultry
production are difficult to overestimate. More than 300 mycotoxins have been shown to induce signs of toxicity in mammalian and avian species (Fink-Gremmels, 1999; Leeson et al., 1995) and this number is increasing. It has been estimated that 25% of the world’s crop production is contaminated with mycotoxins (Fink-Gremmels, 1999). Among all mycotoxins, those from Fusarium species are considered to be the major contaminants of poultry feed. Trichothecenes, zearalenone, fumonisins, moniliformin and fusaric acid are the major Fusarium mycotoxins occurring on a worldwide basis in cereal grains, animal feeds and forages (D’Mello et al., 1999). Furthermore, the trichothecene mycotoxins themselves comprise a vast group of over 100 fungal compounds with the same basic structure (Leeson et al., 1995).
The symptoms of mycotoxicosis can range from acute death to immunosuppression, skin lesions or signs of hepatotoxicity, nephrotoxicity, neurotoxicity, and genotoxicity (Hollinger and Ekperigin, 1999). Biochemical changes in mycotoxicosis vary greatly and a compromised antioxidant system is regarded as one of the most important consequences (Mezes et al., 1999). For example oxidative damage caused by T-2 toxin may be one of the underlying mechanisms for T-2 toxin-induced cell injury and DNA damage, which eventually lead to tumourigenesis (Atroshi et al., 1997). However, the effects of mycotoxins on lipid metabolism and in particular on the fatty acid profile of tissues have received only limited attention (Bryden et al., 1979; Merkley et al., 1987) and any changes in the fatty acid composition of egg yolk as a result of feed contamination with mycotoxins have yet to be reported.
Aurofusarin, a dimeric naphthoquinone metabolite of Fusarium graminearum was first described in 1968 (Morishita et al., 1968), but it is only recently that it has been identified in feed ingredients in Ukraine (Kotyk, 1999), in particular in contaminated grains (Kotyk and Trufanova, 1998), and characterised as a new crop pollutant (Dvorska et al., 2000) (Figure 1). Grains contaminated with this mycotoxin have a pinkish colour; and aurofusarin was found in 11 samples of wheat growing in Ukraine in 1988-1990 (Kotyk and Trufanova, 1990). The major effect of this mycotoxin on poultry was associated with changes in egg yolk colour from yellow-orange to dark-brown (Kotyk et al., 1990). More detailed analyses of the effects of aurofusarin on egg quality were presented by Kotyk et al. (1995). Interestingly, production of the other mycotoxins, zearalenone and deoxynivalenol, by the fungal isolates had no detectable effect on egg quality deterioration (Medentsev et al., 1993).
There were also other changes in poultry metabolism as a result of aurofusarin contamination of the feed (Kotyk, 1999). Aurofusarin is shown to have a profound effect on chicken meat quality (Dvorska, 2000; 2000a). In particular, the protein and fat content of meat were reduced with a significant decrease (by 15.6-27.5%) in concentrations of alanine, valine, leucine, lysine, glutamic acid and glycine in the red muscles (Dvorska, 2000b).
EFFECT OF AUROFUSARIN ON QUAIL EGG COMPOSITION
Quail proved a good model for understanding aurofusarin impact, despite being less susceptible to effects of other toxins than many poultry species. Quail are several times more resistant to ochratoxicosis than chickens or turkeys (Prior et al., 1976); and have a more rapid metabolism of aflatoxin B1 (O’Brien, 1983), which leaves them more resistant to aflatoxin than poults and goslings but less resistant than chickens (Arafa et al., 1981). Aurofusarin did not affect body weight of adult quail after 8 weeks of feeding, however, egg production was slightly decreased (Dvorska et al., 2001). For the period between 4 and 8 weeks of the experiment, control birds laid 344 eggs and those given aurofusarin-contaminated diets only 322 eggs.Egg weight and egg yolk weight at 95-100 days of age were unaffected. After 8 weeks, egg yolk from experimental and control quail had similar lipid concentrations (Table 1). Triacylglycerol was the major lipid fraction of the quail egg yolk, comprising 62.2-63.2%. The phospholipid fraction comprised half that of the triacylglycerol.
Free cholesterol, free fatty acids and cholesterol esters were minor fractions of the egg yolk lipid. There were no differences in the proportions of lipid fractions in the egg yolk due to aurofusarin presence. The phospholipid fraction of the egg yolk consisted of saturated, monounsaturated and polyunsaturated fatty acids. Palmitic (16:0) and stearic (18:0) acids were the major saturated fatty acids comprising together 43.3% and 41.9% in the control and experimental groups, respectively (Table 2). Oleic acid (18:1n-9) was the major monounsaturate in the phospholipid fraction of the egg yolk. Small proportions of palmitoleic (16:1n-7) and cis-vaccenic (18:1n-7) acids were also detected in the egg yolk. Linoleic acid (18:2n-6), arachidonic acid (20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3) were the major polyunsaturates in the phospholipid fraction of the egg yolk. Dietary supplementation with aurofusarin was associated with a significant decrease in the DHA proportion in this lipid fraction.
On the other hand, the proportion of linoleic significantly increased. The proportion of arachidonic acid in the phospholipid fraction did not change. The triacylglycerol fraction of the egg yolk consisted mainly of oleic and palmitic acids. Linoleic acid was the major polyunsaturate in the lipid fraction. As noted in Table 2, the proportion of linoleic acid in the triacylglycerol fraction significantly increased in response to aurofusarin. The cholesterol ester fraction consisted mainly of oleic acid (Table 3). However, linoleic acid, α-linolenic acid, arachidonic acid and DHA were also found in this fraction. As with the phospholipid fraction, the DHA proportion of cholesterol esters significantly decreased in response to aurofusarin. Free fatty acids in the egg yolk included a range of saturated, monounsaturated and polyunsaturated fatty acids (Table 3).
Inclusion of aurofusarin in the quail diet significantly decreased the proportion of DHA and increased linoleic and arachidonic acid proportions in the free fatty acid fraction of the egg yolk. Our work (Dvorska et al., 2001) was the first to show the effects of mycotoxins on the fatty acid composition of egg yolk. However, there is additional evidence for effects of mycotoxins on lipid metabolism. For example, aflatoxin (Merkley et al., 1987; Baldwin and Parker, 1985; Bryden et al., 1979) and fumonisin B1 (Gelderblom et al., 1999) have been shown to alter fatty acid metabolism in vivo and in vitro. In our experiment there were clear changes in the fatty acid profiles of different yolk lipid fractions. One of the reasons for compositional differences might be stimulation of lipid peroxidation by mycotoxins (Surai, 2002).
However, in our experiment only the proportion of DHA decreased, while the overall proportion of polyunsaturated fatty acids (PUFA) actually increased. Therefore, in response to aurofusarin the ratio of ω-6/ω-3 PUFA in the phospholipid fraction increased from 2.72 to 5.62 and in the cholesterol ester fraction this ratio increased from 3.07 to 4.29. Thus, alternative explanations could be an effect of aurofusarin on long chain PUFA synthesis in the liver or their incorporation in the very low density lipoproteins and delivery to the egg yolk. Recently, a hypothesis describing involvement of α-tocopherolquinone as an essential enzyme cofactor for the mitochondrial fatty acid desaturases has been suggested (Infante, 1999). Based on this hypothesis, there are two mechanisms by which aurofusarin may affect fatty acid interconversions. Firstly, decreased concentration of vitamin E in the maternal liver could reduce synthesis of α-tocopherolquinone, which could in turn affect synthesis of DHA. Secondly, it is possible that aurofusarin, possessing the quinone structure, could interfere with α-tocopherolquinone action directly. In both cases the result would be the same: decreased synthesis of DHA in the mitochondria due to an impaired mitochondrial desaturation pathway and compensatory synthesis of arachidonic acid in microsomes due to activation of desaturationelongation reactions. This would be similar to the situation observed in vitamin E deficiency (Infante, 1999). Indeed, molecular mechanisms of the effect of aurofusarin on fatty acid metabolism need further investigation.
Antioxidant levels in the egg yolk from the control group did not vary significantly over a 12-week period of observation (Table 4, Dvorska et al., 2001). However, aurofusarin decreased vitamins E, A and total carotenoid concentrations after 8 weeks of feeding. Furthermore, both the major egg yolk carotenoids, lutein and zeaxanthin, significantly decreased. Inclusion of aurofusarin in the quail diet was also associated with a significantly increased egg yolk susceptibility to lipid peroxidation (Figure 2). It is interesting that in both cases, in Fe-stimulated as well as in spontaneous peroxidation, the accumulation of MDA was significantly enhanced in the egg yolk from the experimental group.
The data indicated that aurofusarin action on egg antioxidants is time-dependent. For example, after 2 weeks of aurofusarin consumption only a slight, but non-significant antioxidant decrease was noted. However, after 4 weeks α-tocopherol, retinol, total carotenoids and lutein concentrations in the egg yolk were significantly decreased. Over the subsequent 4 weeks, only a slight further decrease in the antioxidant concentrations was observed but decreases in α-tocopherol and zeaxanthin content became significant. Exclusion of aurofusarin from the quail diet restored antioxidant concentrations in the egg yolk. Carotenoid concentration returned to initial levels in two weeks, however, it took longer for vitamin A and E levels in egg yolk to recover. After 4 weeks of feeding quail the diet without aurofusarin, concentrations of α- and γ-tocopherols, retinol, total carotenoids, lutein and zeaxanthin in the egg yolk of control and experimental groups were not different. As a result, the egg yolk susceptibility to spontaneous and Fe2+-stimulated lipid peroxidation in the control and experimental quail at the end of experiment (129 days of age) was not different. These results clearly showed a negative effect of aurofusarin on carotenoid and vitamin E accumulation. Mycotoxins are known to decrease antioxidant concentrations in tissues (Surai, 2002).
Aflatoxin can cause poor pigmentation in birds, presumably by interfering with the absorption, transport, and deposition of carotenoids (Tyczkowski and Hamilton, 1987). T-2 toxin consistently depressed the concentrations of vitamin E in plasma (Coffin and Combs, 1981) and liver (Hoehler and Marquardt, 1996) of chickens. On the other hand, dietary inclusion of carotenoids (Leal et al., 1998; 1999; Gradelet et al., 1998) or vitamin E (Hoehler and Marquardt, 1996) has a protective effect against mycotoxicosis. The vitamin A concentration in the egg yolk was also decreased as a result of aurofusarin supplementation of the quail diet. This is in agreement with data indicating that other mycotoxins (aflatoxin) decreased vitamin A concentration in the liver of the chicken (Carnaghan et al., 1966).
Lipid peroxidation is an important mechanism of mycotoxin toxicity. This has been shown for ochratoxin (Marquart and Frohlich, 1992; Hoehler, 1998), T-2 toxin (Mezes et al., 1999; Leal and de Mejia, 1997; Dvorska and Surai, 2001) and other mycotoxins (Leeson et al., 1995). It is not clear if increased susceptibility to peroxidation is due to decreased natural antioxidant concentrations in the egg yolk (vitamin E and carotenoids) or whether aurofusarin itself was accumulated in the egg yolk and was directly involved in lipid peroxidation stimulation. In an in vitro system aflatoxin stimulated lipid peroxidation directly and also decreased vitamin E concentration (Dvorska and Surai, 2001). In contrast, T-2 toxin stimulated lipid peroxidation only in combination with other inducers of peroxidation (Yaroshenko et al., 2003). In general, increased susceptibility to lipid peroxidation could contribute to off-flavours in eggs. Furthermore, decreased concentrations of natural antioxidants in the egg yolk could be translated into decreased hatchability and lower chick viability in early postnatal development (Dvorska, 2001). Compromised antioxidant systems could be a cause of decreased immunocompetence in laying hens as a result of aurofusarin consumption, reported recently (Sakhatsky, 1999).
EFFECT OF AUROFUSARIN ON THE ANTIOXIDANT SYSTEM OF THE QUAIL EMBRYO
Antioxidant systems in the cells provide protection from damaging effects of free radicals and toxic products of their metabolism. These systems play an important role in avian embryonic development (Surai, 1999). They include three major levels of defence. The first level is based on the activity of antioxidant enzymes including superoxide dismutase, glutathione peroxidase and catalase (Surai, 1999a). These enzymes are responsible for the prevention and restriction of free radical formation, since the superoxide radical is considered to be the major radical produced in physiological conditions (Halliwell and Gutteridge, 1999).
The second level of antioxidant defence in the avian embryo is comprised of vitamins A, E, C and carotenoids (Surai, 1999). This level of defence is responsible for restriction and prevention of chain formation and propagation. In particular, vitamin E has a central role during embryonic development and is actively accumulated in embryonic tissues (Surai et al., 1996; 1999). Carotenoids are also believed to play an important role in antioxidant defence of the chicken embryo (Surai and Speake, 1998; Surai et al., 2001). Furthermore, vitamin A can participate in antioxidant defence (Livrea et al., 1996) but its overdose was associated with a compromised antioxidant system in laying hens (Surai et al., 1998) and chickens (Surai et al., 2000; Surai and Kuklenko, 2000). Vitamin C (Surai et al., 1996) and glutathione (Surai, 1999a) are also involved in antioxidant defence of the avian embryo.
The third level of antioxidant defence is based on the construction of specific enzymes that repair damage and reconstitute membranes or remove damaged molecules from the cell (Surai, 1999). It is interesting that selenomethionine can stimulate DNA-repair enzymes (Seo et al., 2002). Experiments in our laboratory showed that quail egg yolk contained a range of natural antioxidants, including α-, γ- and δ-tocopherols and α- and γ-tocotrienols, retinol, lutein and zeaxanthin (Dvorska et al., 2002). The major vitamin E form detected in the egg yolk was α-tocopherol. The concentration of γ-tocopherol in the egg yolk was approximately 10-fold lower compared to α-tocopherol. Tocotrienol concentrations were comparatively low, comprising about 3% of the α-tocopherol values.
During the feeding experiment, egg yolk antioxidant concentrations in the control group did not change. However, aurofusarin inclusion in the quail diet was associated with a significant decrease in antioxidant concentrations. The most pronounced decrease was seen for carotenoids (31-38%). At the same time retinol concentration decreased by 30% and different vitamin E forms decreased by 14% (δ-tocopherol) to 33% (α-tocotrienol).
The hatching period and the first day of postnatal development were characterised by substantial (39-45%) increases in lutein and zeaxanthin concentrations in the liver (Table 7). In contrast, vitamin A concentrations increased to a lesser extent. In the liver of the embryo, five forms of vitamin A were detected. Retinyl palmitate, oleate, stearate, linoleate and retinol represented 41.9; 24.9; 17.6; 12.1 and 3.7% total vitamin A found on the liver respectively. As a result of decreased concentrations of carotenoids and vitamin A, α- and γ-tocopherols in the egg yolk due to aurofusarin supplementation, lutein, zeaxanthin and all vitamin A and E forms were significantly decreased in the embryonic liver and other tissues in day-old birds (Tables 5, 6 and 7). However, aurofusarin did not affect the relative proportions of different forms of vitamin A in the quail liver.
Tissue susceptibility to lipid peroxidation significantly increased in the experimental group in comparison to tissues obtained from the control birds (Table 8). This was observed for both spontaneous and Fe-stimulated peroxidation. Among tissues studied, the brain had the highest susceptibility to lipid peroxidation and was the most sensitive to the aurofusarin effect. Molecular mechanisms of these changes have not been elucidated, however, our preliminary work (Dvorska, 2001) showed that aurofusarin is accumulated in the egg and this could cause changes in yolk colour, since depending on pH aurofusarin can change colour from orange to pink and further to violet (Kotyk, 1999; Dvorska et al., 2002).
Aurofusarin consumption was also associated with decreased fertility and hatchability in chickens (Sakhatsky, 1999) and quail (Dvorska, 2001). Our preliminary study (Dvorska, 2001) revealed that embryonic mortality occurred mainly in the late stages of incubation. We suggested that this could be associated with a compromised antioxidant system. In particular, egg yolk concentrations of α- and γ-tocopherols and tocotrienols, as well as retinol, lutein and zeaxanthin were significantly decreased.
As for the mechanism of this reduction, it is possible that pro-oxidant properties of aurofusarin cause oxidation of antioxidant compounds in the intestine before absorption. In fact, vitamin E oxidation has been shown to occur in the intestine of chickens and turkeys (Sklan et al., 1982). Furthermore, accumulation of aurofusarin in egg yolk could stimulate lipid peroxidation directly, causing a decrease in antioxidant concentrations. Another possibility for the detrimental effect of aurofusarin on antioxidants is a disruption of nutrient absorption in the intestine. For example, malabsorption syndrome was shown in chickens as a result of aflatoxin (Tung and Hamilton, 1973), ochratoxin (Huff and Hamilton, 1975) and T-2 toxin (Coffin and Combs, 1981) consumption.
However, molecular mechanisms of aurofusarin-antioxidant interactions need further investigation. The present study clearly showed that the antioxidant system of the quail embryo was compromised. In this respect, natural antioxidants play an important role in protecting highly unsaturated fatty acids in avian embryonic tissues (Surai, 1999). In particular, vitamin E accumulation in the embryonic liver reaches its highest concentration at the time of hatching (Surai et al., 1996), when oxidative stress occurs, and is considered to be an adaptive mechanism promoting chick survival (Surai, 1999).
In our experiment, in day-old quail all four forms of vitamin E in the liver were decreased. This could place this important tissue at the risk of oxidative damage. Furthermore, vitamin E concentrations in other tissues were also reduced as a result of aurofusarin supplementation of the maternal diet. It could well be that this is just a reflection of a decreased vitamin E concentration in the yolk. Therefore, less vitamin E was available for transfer to embryonic tissues. Similar patterns were observed for lutein and zeaxanthin, which are major carotenoids in the egg yolk and quail tissues. Retinyl palmitate was the major vitamin A form in the liver of day-old quail, comprising 41.7% of total vitamin A. However, retinyl oleate and stearate were present in the liver in reasonable proportions.
This is somewhat different from mammals (Batres and Olson, 1987; Periquet et al., 1988) and from adult gulls (Surai et al., 2000a). These data indicate that decreased retinol level in the egg yolk was associated with decreased concentration of all five forms of vitamin A in the liver. However, it is not clear from this study if decreased availability of retinol for synthesis of retinyl esters in the yolk sac membrane was the only factor contributing to the decreased vitamin A content of the liver. Nevertheless, the fact that proportions of different forms of vitamin A did not change as a result of aurofusarin supplementation is in agreement with this suggestion.
Tissue susceptibility to lipid peroxidation substantially increased as a result of antioxidant
system impairment. Increased MDA accumulation was observed as a result of both spontaneous and Fe-stimulated lipid peroxidation. In fact, the difference was much more pronounced for estimulated lipid peroxidation. These data are in agreement with previous observations (Hoehler et al., 1997), which indicated that stimulation of lipid peroxidation by mycotoxins (ochratoxin A) was higher compared to free peroxidation during stress conditions. The highest susceptibility to lipid peroxidation was observed in the brain, a tissue with the lowest vitamin E concentration and high levels of polyunsaturated fatty acids (Surai et al., 1996).
These data are also in agreement with our previous observations with chicken tissues (Surai et al., 1999a). It is interesting that in the brain of the dayold quail, the increase in lipid peroxidation was higher than for other tissues. This could reflect the low antioxidant potential of the brain; and even a slight decrease in vitamin E concentration, if not compensated by other antioxidants, could lead to increased lipid peroxidation. Whether increased tissue lipid peroxidation is just a reflection of decreased antioxidant concentrations, or whether aurofusarin can also interfere with antioxidant enzymes needs further investigation.
PROTECTIVE EFFECT OF MODIFIED GLUCOMANNANS AGAINST AUROFUSARIN TOXICITY
Effects of aurofusarin in the quail diet on the main PUFAs in the egg yolk are shown in Figures 3-6. Aurofusarin consumption was associated with significant changes in the fatty acid profile of egg yolk. The most dramatic changes were observed in the phospholipid fraction. The proportion of linoleic acid increased by 35.6% with a concomitant decrease in the proportion of docosahexaenoic acid of 44.6% (Figure 3). At the same time, arachidonic acid proportion in the egg yolk lipids remained constant. Inclusion of dietary glucomannan (MycosorbTM, Alltech Inc.) prevented changes in the egg yolk fatty acid profile due to aurofusarin consumption. Changes in the linoleic acid proportion of the triacylglycerol fraction of the quail yolk were similar to those in the phospholipid fraction with a significant increase (43%) of this fatty acid proportion due to aurofusarin consumption (Figure 4). MycosorbTM supplementation prevented this change. In the cholesterol ester fraction the proportion of linoleic acid was unaffected, however, there was a significant reduction in the proportion of DHA (49%) in this fraction due to aurofusarin (Figure 5).
MycosorbTM inclusion into the quail diet decreased changes in DHA proportion in the cholesterol ester fraction, but was not able to completely eliminate them. In the free fatty acid fraction there were also changes in PUFA profiles in response to aurofusarin inclusion in the maternal diet: linoleic acid and arachidonic acid proportions were increased by 65% and 50%, respectively. At the same time DHA proportion in this lipid fraction decreased by 42% (Figure 6). MycosorbTM inclusion helped to overcome changes in PUFA profile in the free fatty acid fraction of the egg yolk.
Aurofusarin consumption reduced concentrations of all vitamin E forms studied (by 18% for
tocopherols and 33-44% for tocotrienols) in the egg yolk (Figure 7). At the same time a protective effect of MycosorbTM was indicated by return of vitamin E concentration to the control levels. Antioxidant systems of the newly hatched quail were also compromised as a result of decreased vitamin E in the egg yolk (Figure 8). For example, α- and γ-tocopherol concentrations in the liver of day-old quail decreased by 36% and γ-tocotrienol by 35%.
MycosorbTM supplementation prevented not only changes in vitamin E concentration in the egg yolk, but was also protective in terms of maintaining antioxidant system activity of the newly hatched quail. In fact, vitamin E concentration in the liver of the 3 day-old quail group was not dissimilar to that of control birds. Concentration of MDA in tissues of newly hatched quail was also significantly decreased with MycosorbTM supplementation to the diet (Figure 9).
The range of mycotoxins that can contaminate poultry feed and their different chemical compositions make protection against toxicity a difficult task. There are various approaches to control or combat mycotoxin problems. The simplest strategy is based on the prevention of the formation of mycotoxins in feeds by special management programmes including storage at low moisture levels and prevention of grain damage during processing (Dawson, 2001; 2001a; Peraica et al., 2002). However, modern agronomic technology is not able to eliminate pre-harvest infection of susceptible crops by fungi (Wood, 1992). Therefore this strategy can only partially be effective; and in countries with warm and humid conditions, this strategy could be quite costly.
Other strategies based on use of microbial or thermal inactivation of toxins, physical separation of contaminated feedstuffs, irradiation, ammoniation and ozone degradation have not been used commercially because they are either timeconsuming or comparatively expensive (Dawson, 2001; 2001a). In recent years, nutritional manipulation has been actively used to enhance animal self-defence against mycotoxins or to decrease detrimental consequences of mycotoxin consumption.
Many compounds have been tested for adsorbent effects, however comparatively few have proven successful. Still fewer – mainly bentonites, zeolites, aluminosilicates and a yeastderived glucomannan – are sold commercially for this purpose. The extent to which various compounds adsorb or bind specific toxins varies considerably. Some (zeolites) only bind aflatoxin, leaving other mycotoxins such as T-2 unaltered. In contrast, a glucomannan derived from yeast cell walls (MycosorbTM) has been shown to be effective against a wide range of mycotoxins (Devegowda et al., 1998; Raju and Devegowda, 2000; Swamy et al., 2002; 2002a). It is interesting that mycotoxin adsorbents can substantially improve antioxidant systems in animals. This effect depends on the mycotoxin adsorption capacity or binding activity.
For example, zeolites alone were not effective in preventing the toxic effects of T-2 toxin (Dvorska and Surai, 2002). In contrast, the inclusion of yeast glucomannan in quail diets containing T-2 toxin significantly slowed depletion of natural antioxidants and vitamin A in the liver. This protective effect has been attributed to the high adsorbent capacity that modified glucomannans have for T-2 toxin. It is also possible that mycotoxin adsoption also prevents oxidative stress in the intestine due to T-2 toxin. Oxidative stress leads to damage of the enterocytes and thus reduces absorption of dietary antioxidant nutrients. Our data also show that the inclusion of the yeast glucomannan in a diet contaminated with T-2 toxin significantly decreased tissue susceptibility to lipid peroxidation. However, the adsorbent material could not completely mitigate the powerful stimulating effect of T-2 toxin on lipid peroxidation.
In our experiment (Dvorska et al., 2003), a protective effect of MycosorbTM against aurofusarin was almost complete, since it prevented changes in fatty acid and antioxidant composition in the egg yolk as well as helped to maintain vitamin E concentration in the liver of the newly hatched quail. Our observations, based on an effective HPLC system to separate aurofusarin, confirmed a high absorptive capacity of MycosorbTM for aurofusarin. It seems likely that a combination of mycotoxin adsorbents with natural antioxidants, e.g. organic selenium and vitamin E, could be the next step in curbing the damaging effects of mycotoxins on poultry.
CONCLUSIONS
Among hundreds of mycotoxins studied, aurofusarin has received only limited attention. However, data accumulated thus far make it clear that this Fusarium pigment should be considered a mycotoxin. Our study confirmed that aurofusarin is transferred from the feed to the egg yolk, and due to its own colour being pH-dependent could cause colour change from yellow via red and pink to violet.
Therefore a combination of this colour and the carotenoid-based yellow colour of the yolk could be responsible for those changes. Furthermore, aurofusarin consumption is associated with deterioration of chicken meat quality (Dvorska, 2000; 2000a; 2000b), compromised immunity in of laying hens (Sakhatsky, 1999) and quail (Dvorska, 2001a; Dvorska et al., 2001) and decreased fertility and hatchability in chickens (Sakhatsky, 1999) and quail (Dvorska, 2001a; Dvorska et al., 2001).
Aurofusarin consumption was associated with significant changes in fatty acid profile of egg yolk and decreased antioxidant concentration in the egg yolk and embryonic tissues of quail. As a result of antioxidant depletion, susceptibility to lipid peroxidation significantly increased. MycosorbTM had a protective effect against changes in fatty acid and antioxidant composition of eggs. In fact, most of the detrimental changes in egg yolk and embryonic tissues of quail caused by aurofusarin consumption were prevented by MycosorbTM.
REFERENCES
Arafa, A.S., R.J. Bloomer, H.R. Wilson, C.F. Simpson and R.H. Harms. 1981. Susceptibility of
various poultry species to dietary aflatoxin. Brit. Poult. Sci. 22:431-436.
Atroshi, F., A. Rizzo, I. Biesse, P. Veijalainen, E. Antila and T. Westermarck. 1997. T-2 toxininduced DNA damage in mouse livers: the effect of pre-treatment with coenzyme Q10 and α-tocopherol. Molecular Aspects of Medicine 18:255-258.
Baldwin, S. and R.S. Parker. 1985. Effects of dietary fat level and aflatoxin B1 treatment on rat hepatic lipid composition. Food and Chem. Toxicol. 23:1049-1055.
Batres, R.O. and J.A. Olson. 1987. Relative amount and ester composition of vitamin A in rat hepatocytes as a function of the method of cell preparation and total liver stores. J. Nutr. 117:77-82.
Bryden, W.L., R.B. Cumming and D. Balnave. 1979. The influence of vitamin A status on the
response of chickens to aflatoxin B1 and changes in liver lipid metabolism associated with
aflatoxicosis. Brit. J. Nutr. 41:529-540.
Carnaghan, R.B., G. Lewis, D.S. Patterson and R. Allcroft. 1966. Biochemical and pathological aspects of groundnut poisoning in chickens. Pathologia Veterinaria 3:601-615.
Coffin, J.L. and G.F. Combs, Jr. 1981. Impaired vitamin E status of chicks fed T-2 toxin. Poult. Sci. 60:385-392.
D’Mello, J.P.F., C.M. Placinta and A.M.C. MacDonald. 1999. Fusarium mycotoxins: a review of global implications for animal health, welfare and productivity. Anim. Feed Sci. Technol. 80:183-205.
Dawson, K.A. 2001. The application of yeast and yeast derivatives in the poultry industry. Proc. Australian Poultry Sci. Symposium 13:100-105.
Dawson, K.A. 2001a. Understanding the absorption characteristics of yeast cell wall preparations associated with mycotoxin binding. In: Biotechnology in the Feed industry: Proceedings of Alltech’s 17th Annual Symposium (T.P. Lyons and K.A. Jacques, eds). Nottingham University Press, Nottingham, UK, pp. 169-181.
Devegowda, G., M.V.L.N. Raju and H.V.L.N. Swamy. 1998. Mycotoxins: Novel solutions for
their counteraction. Feedstuffs 70:12-15.
Dvorska, J.E. 2000. The effect of aurofusarin on chicken meat quality. Vestnik of the Sumy
Agrarian University, Sumy, Ukraine 5:46-49.
Dvorska, J.E. 2000a. The chicken meat quality during aurofusariotoxicosis. Proc. Internat. Conf. on Progressive Technologies in Poultry in 21st Century. Kyiv, Ukraine. pp.32-35.
Dvorska, J.E. 2000b. Effect of dimeric naphthoquinone aurofusarin produced by Fusarium graminearum on chicken meat quality. Proc. XXI World’s Poultry Congress, Montreal,
Canada. CD-ROM.
Dvorska, J. 2001. Effect of aurofusarin, a mycotoxin produced by Fusarium graminearum,
on Japanese quails. Abstracts of International Symposium Bioactive Fungal metabolites - Impact and Exploitation, University of Wales Swansea, pp. 32-33.
Dvorska, J.E. 2001a. Influence of sorbents during aurofusarinotoxicosis and T-2 - toxicosis of quails and hens. PhD Thesis. Institute of Experimental and Clinical Veterinary Medicine of UAAS, Kharkov, Ukraine.
Dvorska, J.E. and P.F. Surai. 2001. Effect of T-2 toxin, zeolite and Mycosorb on antioxidant systems of growing quail. Asian-Aust. J. Anim. Sci. 14:1752-1757.
Dvorska, J. and P.F. Surai. 2001. Stimulating effect of aflatoxin B1 on lipid peroxidation in the in vitro model systems. Proceedings of 6th International Symposium of Poisonous Plants - Glasgow, Scotland, p. 21.
Dvorska, J.E., T.I. Fotina, A.N. Kotyk and V.O. Trufanova. 2000. F. graminearum dimmeric
naphthoquinone metabolite aurofusarin - the new factor of crop pollution. Proceedings of the Xth International Congress on Animal Hygiene. Maastricht, The Netherlands, Vol. 1, pp.412-414.
Dvorska, J.E., P.F. Surai and N.H.C. Sparks. 2001. Mycotoxin aurofusarin: effect on quail. Scientific programme and abstracts of 6th International Symposium on Poisonous plants, Glasgow, UK, p. 86.
Dvorska, J.E., P.F. Surai, B.K. Speake and N.H.C. Sparks. 2002. Antioxidant systems of the
developing quail embryo are compromised by mycotoxin aurofusarin. Comparative Biochemistry and Physiology 131C:197-205.
Dvorska J.E, P.F. Surai, B.K. Speake and N.H.C. Sparks. 2003. Protective effect of modified
glucomannans against aurofusarin-induced changes in quail egg and embryo. Comparative
Biochemistry and Phisiology (in press).
Fink-Gremmels, J. 1999. Mycotoxins: their implications for human and animal health.
Veterinary Quarterly 21:115-120.
Gelderblom, W.C., S. Abel, C.M. Smuts, S. Swanevelder and S.D. Snyman. 1999. Regulation
of fatty acid biosynthesis as a possible mechanism for the mitoinhibitory effect of fumonisin B1 in primary rat hepatocytes. Prostaglandins Leukotrienes and Essential Fatty Acids 61:225-234.
Gradelet, S., A.M. Le BoN, R. Berges, M. Suschetet and P. Astorg. 1998. Dietary carotenoids inhibit aflatoxin B1-induced liver preneoplastic foci and DNA damage in the rat: role of the modulation of aflatoxin B1 metabolism. Carcinogenesis 19:403- 411.
Halliwell, B. and J.M.C. Gutteridge. 1999. Free Radicals in Biology and Medicine. Third Edition, Oxford University Press, Oxford.
Hoehler, D. 1998. Ochratoxin A in food and feed: occurrence, legislation and mode of action. European J. Nutr. 37:2-12.
Hoehler, D. and R.R. Marquardt. 1996. Influence of vitamins E and C on the toxic effects of
ochratoxin A and T-2 toxin in chicks. Poult. Sci. 75:1508-1515.
Hoehler, D., R.R. Marquardt and A.A. Frohlich. 1997. Lipid peroxidation as one mode of action in ochratoxin A toxicity in rats and chicks. Can. J. Anim. Sci. 77:287-292.
Hollinger, K. and H.E. Ekperigin. 1999. Mycotoxicosis in food producing animals. Veterinary Clinics of North America. Food Animal Pracice, 15:133-165.
Huff, W.E. and P.B. Hamilton. 1975. Decreased plasma carotenoids during ochratoxicosis. Poult. Sci. 54:1308-1310.
Infante, J.P. 1999. A function for the vitamin E metabolite α-tocopherol quinone as an essential enzyme cofactor for the mitochondrial fatty acid desaturases. FEBS Letters 446:1-5.
Kotyk, A.N. 1999. Poultry mycotoxicosis. Poultry Research Institute, Ukraine.
Kotyk, A.N. and V.A. Trufanova 1990. Aurofusarin is the new factor of a grain contamination. Nauchno-techicheskij Bulletin of the Ukrainian Poultry Research Institute, Kharkov, 29:39-41.
Kotyk, A.N. and V.A. Trufanova. 1998. Detection of naphthoquinone fusariotoxin aurofusarin in wheat. Mycology and Phytopathology 32:58-61.
Kotyk, A.N., V.A. Trufanova and V.A. Breslavets. 1990. A syndrome of changing egg quality. Nauchno-technicheskij Bulletin of the Ukrainian Poultry Research Institute, Kharkov, 29:41-42.
Kotyk, A.N., V.A. Trufanova,V.A. Brestlavets and Z.T. Metasheva. 1995. Egg quality in Rhode Island Red hens fed by Fusarium graminearum culture Proceedings of the 6th European Symposium on the Quality of Eggs and Egg products. Zaragoza, Spain, pp. 263-266.
Leal, M. and E.G. de Mejia. 1997. Toxicological and nutritional implications of T-2 toxin. Food Sci. and Tech. Intl. 3:241-250.
Leal, M., E.G. de Mejia, F. Ruiz and A. Shimada. 1998. Effect of carotenoids on cytotoxicity of T-2 toxin on chicken hepatocytes in vitro. Toxicology in vitro 12:133-139.
Leal, M., A. Shimada, F. Ruiz and E. Gonzalez de Mejia. 1999. Effect of lycopene on lipid
peroxidation and glutathione-dependent enzymes induced by T-2 toxin in vivo. Toxicol. Lett. 109:1-10.
Leeson, S., G. Diaz and J.D. Summers. 1995. Poultry metabolic Disorders and Mycotoxins. University Books. Guelph, Canada.
Livrea, M.A., L. Tesorirre and H.J. Friesleben. 1996. Vitamin A as an antioxidant. In: Handbook of Antioxidants (E. Cadenas and L. Packer, eds). Marcel Dekker, pp. 371-405.
Medentsev, A.G. and V.K. Akimenko. 1998. Naphthoquinone metabolites of the fungi.
Phytochemistry 47:935-959.
Medentsev, A.G., Kotyk, V.A. Trufanova and V.K. Akimenko. 1993. Identification of aurofusarin in Fusarium graminearum isolates, causing a syndrome of worsening of egg quality in chickens. Prikladnaya Biokhimia and Mikrobiologia, 29:542-546.
Merkley, J.W., R.J. Maxwell, J.G. Phillips and W.E. Huff. 1987. Hepatic fatty acid profiles in aflatoxinexposed broiler chickens. Poultry Sci. 66:59-67.
Mezes, M., M. Barta and G. Nagy. 1999. Comparative investigation on the effect of T-2 mycotoxin on lipid peroxidation and antioxidant status in different poultry species. Res. Vet. Sci. 66:19-23.
Morishita, E., T. Takeda and S. Shibata. 1968. Metabolic products of fungi. XXIX. The structure of aurofusarin. Chemical and Pharmaceutical Bulletin (Tokyo) 16:411-413.
O’Brien, K., E. Moss, D. Judah and G. Neal. 1983. Metabolic basis of the species difference to aflatoxin B1 induced hepatotoxicity. Bioch. and Biophysical Res. Communications 114:813-821
Peraica, M., A.M. Domijan, Z. Jurjevic and B. Cvjetkovic. 2002. Prevention of exposure to
mycotoxins from food and feed. Arh. Hig. Rada Toksikol. 53:229-237.
Periquet, B., W. Lambert, A. Bailly, I. Tomatis, J. Ghisolfi, A.P. de Leenheer and J.P. Thouvenot. 1988. Fatty acid composition and kinetic behaviour of liver retinyl esters in vitamin A sufficient and deficient rats. Clin. Chim. Acta 172:275-289.
Prior, M.G., C.S. Sisodia and J.B. O’Neil. 1976. Acute oral ochratoxicosis in day-old White
Leghorns, turkeys and Japanese Quail. Poult. Sci. 55:786-790.
Raju, M.V. and G. Devegowda. 2000. Influence of esterified glucomannan on performance and organ morphology, serum biochemistry and haematology in broilers exposed to individual and combined mycotoxicosis (aflatoxin, ochratoxin and T-2 toxin). Br. Poult. Sci. 41:640-650.
Sakhatsky, I.M. 1999. Effect on Fusarium graminearum mycotoxins on reproduction and
immunity of laying hens. Veterinary Medicine of Ukraine 9:34-35.
Seo, Y.R., C. Sweeneyand and M.L. Smith. 2002. Selenomethionine induction of DNA repair
response in human fibroblasts. Oncogene 21:3663- 3669.
Sklan, D., I. Bartov and S. Hurwitz. 1982. Tocopherol absorption and metabolism in the chick and turkey. J. Nutr. 112:1394-1400.
Surai, P.F. 1999a. Tissue-specific changes in the activities of antioxidant enzymes during the development of the chicken embryo. Brit. Poultry Sci. 40:397-405.
Surai, P.F. 1999. Vitamin E in avian reproduction. Poultry Avian Biol. Rev. 10:1-60.
Surai, P.F. 2002. In: Natural Antioxidants in Avian Nutrition and Reproduction. Nottingham
University Press, Nottingham, UK.
Surai, P.F. and B.K. Speake. 1998. Distribution of carotenoids from the yolk to the tissues of the chick embryo. J. Nutr. Biochem. 9:645-651.
Surai, P.F. and T.V. Kuklenko. 2000. Effects of vitamin A on the antioxidant systems of the
growing chicken. Asian-Australian J. Anim. Sci. 13:1290-1295.
Surai, P.F., R.C. Noble and B.K. Speake. 1996. Tissue-specific differences in antioxidant
distribution and susceptibility to lipid peroxidation during development of the chick embryo. Biochim. Biophys. Acta 1304:1-10.
Surai, P.F., I.A. Ionov, T.V. Kuklenko, I.A. Kostjuk, A. MacPherson, B.K. Speake, R.C. Noble, N.H.C. Sparks. 1998. Effect of supplementing the hen’s diet with vitamin A on the accumulation of vitamins A and E, ascorbic acid and carotenoids in the egg yolk and in the embryonic liver. Brit. Poult. Sci. 39:257-263.
Surai, P.F., R.C. Noble and B.K. Speake. 1999. Relationship between vitamin E content and
susceptibility to lipid peroxidation in tissues of the newly hatched chick. Brit. Poult. Sci. 40:406-410.
Surai, P.F., B.K. Speake, R.C. Noble and N.H.C. Sparks. 1999a. Tissue-specific antioxidant profiles and susceptibility to lipid peroxidation of the newly hatched chick. Biol. Trace Elem. Res. 68:63-78.
Surai, P.F., T. Kuklenko, I. Ionov, R. Noble and N. Sparks. 2000. Effect of vitamin A on antioxidant system of the chick during early postnatal development. Brit. Poult. Sci. 41:454-458.
Surai, P.F., N.K. Royle and N.H.C. Sparks. 2000a. Fatty acid, carotenoid and vitamin A composition of tissues of free living gulls. Comp. Biochem. Physiol. 26A:387-396.
Surai, P.F., B.K. Speake and N.H.C. Sparks. 2001. Carotenoids in avian nutrition and embryonic development. 2. Antioxidant properties and discrimination in embryonic tissues. J. Poultry Sci. 38:117-145.
Swamy, H.V., T.K. Smith, E.J. MacDonald, H.J. Boermans and E.J. Squires. 2002. Effects of
feeding a blend of grains naturally contaminated with Fusarium mycotoxins on swine performance, brain regional neurochemistry, and serum chemistry and the efficacy of a polymeric glucomannan mycotoxin adsorbent. J. Anim. Sci. 80:3257-3267.
Swamy, H.V., T.K. Smith, P.F. Cotter, H.J. Boermans and A.E. Sefton. 2002a. Effects of
feeding blends of grains naturally contaminated with Fusarium mycotoxins on production and metabolism in broilers. Poult. Sci. 81:966-975.
Tung, H.T. and P.B. Hamilton. 1973. Decreased plasma carotenoids during aflatoxicosis. Poult. Sci. 52:80-83.
Tyczkowski, J.K. and P.B. Hamilton. 1987. Altered metabolism of carotenoids during aflatoxicosis in young chickens. Poult. Sci. 66:1184-1188.
Yaroshenko F.A., J.E. Dvorska and P.F. Surai. 2003. Effect of T-2 toxin on lipid peroxidation in an in vitro model system. Proceedings of the Second World Mycotoxin Forum, Noordwijk, The Netherlands, p.140.
Wood, G.E. 1992. Mycotoxins in foods and feeds in the United States. J. Anim. Sci. 70:3941-3949.
