Animal Nutrition and Feed Technology
Year : 2003, Volume : 3, Issue : 1
First page : ( 45) Last page : ( 51)
Print ISSN : 0972-2963.

Screening for Aflatoxin and Effect of Moisture, Duration of Storage and Form of Feed on Fungal Growth and Toxin Production in Livestock Feeds

Gowda N.K.S.*, Malathi V., Suganthi R.U.

Toxicology Laboratory, Animal Nutrition Division, National Institute of Animal Nutrition and Physiology, Bangalore-560 030, India.

*Reprint requeset: Dr. N.K.S. Gowda, Tel: +91-80-5711304; Fax: +91-80-5711420; E-mail: gowda@nainpbng.kar.nic.in

Received:  23  March,  2002.

Abstract

Estimation of aflatoxin content of several livestock feeds and feed ingredients indicated the presence of aflatoxin (10–56 ppb AF B₁) in compounded feeds. Samples of groundnut cake had aflatoxin content of 279 ppb (AF B₁) and 39 ppb (AF B₂) and samples of wheat bran, rice bran and rice polish showed negligible aflatoxin content. Fodder samples of maize, sorghum, gram husk and coffee husk contained no detectable aflatoxin. Storage studies with different moisture levels and duration of storage showed a trend of increased mold growth at moisture level above 15% and was highest during 7–21 days of storage (3.66–3.83 logCFU/g). Feeds stored in air-tight containers at 0% moisture level showed no fungal growth and at below 7.5% moisture level there was minimum fungal growth (3.18–4.18 logCFU/g). The aflatoxin (B₁) production was maximum (P<0.05) between 12.5–17.5% moisture level upto 14 days of storage. The average aflatoxin (B₁) production was highest (P<0.05) at 15% moisture level and 28 days of feed storage (15 ppb) and was well within the permissible limit of 20–30 ppb. At 15% moisture level for 14 days of storage the fungal growth and aflatoxin (B₁) production was maximum (P<0.01) in flake (unground) form as compared to the ground form. The results of this study suggested that the moisture level in feeds should be less than 10% for safe storage and feeds with above 12.5% moisture level should be used within a week period or should be dried for safe storage.

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Key words

Livestock feeds, Aflatoxin, Moisture, Storage, Fungus.

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