Use of Toxin Binders in livestock industry: a review

Livestock enterprises faces the maximum loss is owed to the contamination of animal feed ingredients and compounded feeds by moulds and its toxic metabolites known as mycotoxin. Some of the primary toxigenic moulds and mycotoxins are indicated as following:

 

 

 

 

 

 

Among these, the most thoroughly studied and best understood of the mycotoxins are the aflatoxins. The aflatoxins (AF), a class of mycotoxins produced by the common mould Aspergillus flavus Link and Aspergillus parasiticus Speare. Major forms of aflatoxin include B1, B2, G1, and G2, with aflatoxin B1 being the most common and biologically active component (1). All four have been detected as contaminants of crops before harvest, between harvesting and drying, during storage, and after processing and manufacturing (2).

The primary mechanisms through which mycotoxins affect animals are (3):

1. Reduction of feed intake
2. Reduced nutrition (reduced nutrient content of the feed, reduced nutrient absorption and altered nutrient metabolism)
3. Immunosuppression
4. Mutagenicity
5. Teratogenicity
6. Cellular death

Chronic exposure to the mycotoxins may significantly alter productivity, which can mean the difference between profit and loss to the livestock industry. Consequently, practical and effective methods to detoxify toxins-containing feedstuffs are in great demand. Various physical (grain cleaning/seperation, heating, irradiation), chemical (ammoniation, sodium bisulfite) and biological approaches (microbial, non-toxic strains) to counteract the mycotoxins problem have been reported (4 & 5) but these methods have certain limitations like they are impractical, ineffective and potentially unsafe.

Recent studies have shown that the addition of certain adsorbents to contaminated diets can greatly reduce the bioavailability of toxins in the gastrointestinal tract (6&7). Some mycotoxin adsorbents are given below:

1) Silicate Products:

Phyllosilicates (silicate sheets): Clays [Montmorillonite, bentonite and Hydrated Sodium Calcium Aluminosilicate (HSCAS)].
Tectosilicate (silicate frameworks): Zeolites and Clinoptilolite.
2) Carbon Products:

Activated or superactivated charcoal.
3) Glucan products

4) Inorganic polymers:

Cholestyramine.
Polyvinylpyrrolidone (PVP).
Among all these adsorbants, HSCAS (AflabondTM) has been the most extensively studied because it formed a more stable complex with aflatoxin than many other compounds evaluated in vitro and was selected for extensive in vivo application in a varied number of farm animals. The first report of the use of HSCAS in diet to adsorb aflatoxin was made in 1987 (8 & 9).

In chickens, it was found that 0.5% HSCAS in diet reduces the bioavailability of aflatoxin and lessened the growth inhibitory effect of feeding 7.5 mg/kg AFBI. Many of the livers from chicks fed diets containing 7.5 mg/kg AFBI were friable and pale in appearance. Liver from broiler and chicks consuming control, HSCAS, or HSCAS + 7.5 mg/kg AFBI diets appeared normal (7).

A number of literatures are available on the use of HSCAS as a toxin binder in pig industry. Diet containing 0.5% HSCAS protected the pigs against the toxic effects of aflatoxin. There were no differences in weight gain, feed conversion, hematology, serum biochemistry or the results of macroscopic and microscopic pathologic examination between the control and HSCAS-treated groups, whereas these parameters were drastically altered in the aflatoxin-alone group (10 & 11). Another report showed the improvement of daily gains in crossbred pigs containing 0.5 % HSCAS with 840 µg aflatoxin B1/kg feed during 49 days trial. Aflatoxicosis can be effectively ameliorated by the use of HSCAS in diet than the addition of folic acid or selenium, and provided an improvement in blood clinical chemistry values and in cell-mediated immune function, in comparison with the aflatoxin B1 control group (12).

HSCAS (0.5 %) has also been used in the diet containing 200 mg aflatoxin/kg to reduce the secretion of aflatoxin M1 into milk of lactating dairy cows. Aflatoxin M1 excretion was reduced in 24% and the carry-over of the mycotoxin was reduced in 44% when the aflatoxin contamination was 100mg/kg feed and the amount of HSCAS used was 1.0% (13).

The potential of HSCAS to reduce aflatoxin M1 in dairy goat's milk was investigated. The results showed that addition of 4% hydrated sodium calcium aluminosilicate in the diet may not affect the nutritional quality of goat's milk. In addition, 4% HSCAS in the diet did not significantly affect feed intake during the study. The combination of 4% hydrated sodium calcium aluminosilicate with aflatoxin at 200 ppb in the diet of dairy goats resulted in an overall reduction of 86.9% of aflatoxin M1 residue. Whereas 1% hydrated sodium calcium aluminosilicate to the diet containing 100 ppb of aflatoxin resulted in a 51.9% reduction of aflatoxin M1 (14).

HSCAS (2%) has been added to the diets of lambs containing 2.6 mg of aflatoxin/kg feed and was found to protect against the clinical signs of aflatoxicosis (15). The HSCAS at a concentration of 0.5 % of the diet significantly diminished many of the adverse effects caused by aflatoxins in minks (16) and turkeys (17).

So hydrated sodium calcium aluminosilicate (HSCAS) has an ability to adsorb aflatoxin with high affinity. Addition of HSCAS in the diet contaminated with aflatoxin has shown a protective effect against the development of aflatoxicosis in a variety of farm animals by forming the stable complex with toxin so reduces the absorption and bioavailability of these toxins.

How is Aflabond unique?

The HSCAS raw material added to Aflabond (a product of Montajat- Saudi Arabia) undergoes a sequential triple kilning and chemical treatment that removes the naturally binding moisture and other organic material at the active sites of adsorption. The surface area increases many folds, meant for mycotoxin adsorption. This helps in reducing the addition ratio in the feed to 500- 750g per ton of feed, instead of 2.5- 5 kg/ MT of feed.

Low moisture removes the ambient environment required for fungal and bacterial growth in the feed.

The organic acids used are volatile free acids, thus they keep fuming inside the feed while in storage. This facilitates the killing of live fungus and other organic material, inhibits maturing of the spores, and later provides adequate gut acidification.

Low addition ratio is favorable for better palatability of feed, economy and logistics handling.

 

References

1. Betina, V., 1989. Biological effects of mycotoxins. In: V. Betina (Editor), Mycotoxins: Chemical, Biological and Environmental Aspects. Elsevier, Amsterdam, pp. 42-58.
2. Bonna, R.J., Aulerich, R.J., Bursian, S.J., Poppenga, R.H., Braselton, W.E. and Watson, G.L., 1991. Efficacy of hydrated sodium calcium aluminosilicate and activated charcoal in reducing the toxicity of dietary atlatoxin to mink. Arch. Environ. Contam. Toxicol., 20: 441-447.
3. Busby, W. F., Jr., and G. N. Wogan, 1981. Aflatoxins. Pages 3-27 in: Mycotoxins and N-Nitrosocompounds, Environmental Risks. Vol. 2. R. C. Shank, ed. CRC Press Inc., Boca Raton, FL.
4. Carson, M. S., and T. K. Smith. 1983. Role of bentonite in prevention of T-2 toxicosis in rats. J. Anim. Sci. 57:1498.
5. Council for Agricultural Science and Technology, 1989. In: K.A. Nisi (Editor), Mycotoxins: Economical and Health Risks. Council for Agricultural Science and Technology, Ames, pp. 1-91.
6. Davidson, J.N., Babish, 1.G., Delaney, K.A., Taylor: D.R and Phillips, T.O., 1987. Hydrated sodium calcium aluminosilicate decreases the bioavailability of aflatoxin in the chicken. Poult. Sci., 66 (Suppl. I): 89.
7. Doyle, M.P., Applebaum, RS., Brackett, RE. and Marth, E.H., 1982. Physical, chemir.al and biological degradation of mycotoxins in foods and agricultural commodities. J. Food Prot., 45: 964-971.
8. Harvey, R.B., Kubena, L.F., Phillips, T.O., Corrier, D.E., Elissalde, M.H. and Huff, W.E., 1991. Diminution of aflatoxin toxicity to growing lambs by dietary supplementation with hydrated sodium calcium aluminosilicate. Am. J. Vet. Res., 52: 152-156.
9. Harvey, R.B., Kubena, L.F., Phillips, T.O., Huff, W.E. and Corrier, D.E., 1989. Prevention of aflatoxicosis by addition of hydrated sodium calcium aluminosilicate to the diets of growing barrows. Am. J. Vet. Res., 50: 416-420.
10. Harvey, R.B., Kubena, L.F., Phillips, T.O., Corrier, D.E., Elissalde, M.H. and Huff, W.E., 1991. Diminution of aflatoxin toxicity to growing lambs by dietary supplementation with hydrated sodium calcium aluminosilicate. Am. J. Vet. Res., 52: 152-156.
11. Harvey, R.B., Kubena, L.F., Phillips, T.D., Huff, W.E. and Corrier, D.E., 1989. Prevention of clinical signs of aflatoxicosis with hydrated sodium calcium aluminosilicate added to diets. Proc. 20th Annual Meeting of the American Association of Swine Practitioners, Des Moines, Iowa, pp. 99-102.
12. Harvey, R.B., Phillips, T.D., Ellis, J.A., Kubena, L.F., Huff, W.E. and Petersen, H.D., 1991. Effects on aflatoxin M1 residues in milk by addition of hydrated sodium calcium aluminosilicate to aflatoxin-contaminated diets of dairy cows. Am. J. Vet. Res., 52: 1556-1569.
13. Kubena, L. F., W. E. Huff, R. B. Harvey, A. G. Yersin, M. H. Elissalde, D. A. Witzel, L. E. Giroir, T. D. Phillips, and H. D. Petersen, 1991. Effects of a hydrated sodium calcium aluminosilicate on growing turkey poults during aflatoxicosis. Poultry Sci. 70:1823-1830.
14. Lindemann, M.D., BIodgett, D.J., Schurig, G.G. and Kornegay, E.T., 1989. Evaluation of potential ameliorators of aflatoxicosis in weanling/growing swine. 1. Anim. Sci., 67 (Suppl. 2): 36.
15. Phillips, T. D., L. F. Kubena, R. B. Harvey, D. R. Taylor, and N. D. Heidelbaugh. 1988. Hydrated sodium calcium aluminosilicate: a high affinity sorbent for aflatoxin. Poult. Sci. 67: 243-247.
16. Phillips, T.D., Kubena, L.F., Harvey, R.B., Taylor, D.R. and Heidelbaugh, N.D., 1987. Mycotoxin hazards in agriculture: new approach to control. J. Am. Vet. Med. Assoc., 12: 1617.
17. Samarajeewa, V., Sen, A.e., Cohen, M.D. and Wey, C.I., 1990. Detoxification of aflatoxins in foods and feeds by physical and chemical methods. J. Food Prot., 53: 489-501.
18. Smith, E.E., Phillips, T.D., Ellis, J.A., Harvey, R.B., 'Kubena, L.F., Thompson, J. and Newton, G., 1994. Dietary hydrated sodium calcium aluminosilicate reduction of aflatoxin M1 residue in dairy goat milk and effects on milk production and components. J. Anim. Sci., 72: 677-682.

•1. Gupta, A., PhD scholar- Division of Medicine, Indian Veterinary research Institute, Izatnagar (Bareilly), India

•2. Agrawal, P.*, Marketing Manager, Montajat Pharmaceuticals, Saudi Arabia