[Aflatoxin inactivation after ammonia treatment. In vitro studies on detoxified peanut meals]

The maximum allowable tolerance of aflatoxins in animal feeds is becoming lower and lower, and it is obvious that the fairly high level of aflatoxin B1 found in almost all peanut meals in recent years restricts this protein source for use in the diets of most animal species. Among the different chemical methods for aflatoxin inactivation, treatment by gaseous ammonia under a pressure of 2 to 3 bars, appears a very attractive solution because it may be achieved by a fairly easy and rapid procedure. This treatment markedly reduces--up to 95 p. 100--the aflatoxins content of the meal. An increase in the nitrogen content, mainly in the non protein form, is observed. Ammoniation has no adverse effect on in vitro pepsin digestibility and even improves the sensitivity of the meal towards proteases. It slightly reduces protein deamination in the artificial rumen and nitrogen solubility in a buffer solution at pH 7,5; these effects seem to be favourable for the utilization of the treated meals by rumiinants. The amino acid compostion of the meal is not significantly changed, particularly with regard to total and available lysine. However, cystine undergoes partial destruction; but this loss could be counterbalanced by a supply of synthetic methionine.