A preliminary study on the physiological effects of aflatoxin B-1 lactating water buffaloes

Aflatoxin B-1 is one of the biologically active mycotoxins, produced as contaminants in human and animal food by a variety of spoilage molds. The effects of administering aflatoxin B-1 on plasma proteins, total thyroxine, cholesterol, zinc and iron were studied in eight lactating buffaloes (3rd and 8th season of lactation). The toxin was first tested in one animal which received single doses of 400, 1000 and 1500 ug each, mixed with 1 Kg ration, given one week apart. Blood, milk and urine samples were collected over the next 120 hrs. The toxin was not detected in either milk or urine. One week later, the latter dose was offered daily, but the animal lost its appetite and did not consume any of the ration offered on the second day. On the third day through the sixth, the toxin (1500 ug in 5 ml chloroform) was injected into the rumen through the flank region using a long needle and a syringe. However, the toxin could not be detected in either milk or urine. After another week, the dose was increased to 5000 ug intraruminally given for 2 days. The toxin appeared in milk and urine. The other seven animals were then included in the experiment and blood samples were collected 10 and 34 hours after dosing. The results obtained (from the pilot test) showed a transient decrease in serum albumin which lasted for 10-24 hours after oral administration of 400, 1000 and 1500 ug in food. This phenomenon was also confirmed in all animals at 34 hrs. after the intraruminal administration of 5000 ug (p>0.01). On the other hand, serum cholesterol was increased (P>0.01). Serum zinc was also increased though insignificantly. However, no appreciable changes were noted in either serum iron or total thyroxine. This experiment has shown that physiological responses may occur before the detection of the toxin in body fluids. It is suggested that measurement of plasma proteins and cholesterol can be used as a test for the toxic effect of aflatoxin, especially at low doses; a case similar to feeding animals on foods contaminated with aflatoxine