Effect of zearalenone on dairy cows.

Doses of 99% pure zearalenone (0.0, 31.25, 62.5, 125.0, 250.0, or 500.0 mg) in gelatin capsules were given once a day per os to 18 nonpregnant, nonlactating, multiparous dairy cows for 2 consecutive estrous cycles. There was no effect (P less than 0.10) on serum progesterone concentrations, RBC, WBC, PCV, hemoglobin, and estrous cycle length. Differential cell counts, clinical health, and sexual behavior were not affected by the zearalenone. One cow from each of the groups given zearalenone and a control were euthanatized at the end of the study. The zearalenone had no effect on the terminal bone marrow smears and did not induce any gross lesions discernible at necropsy or any microscopic lesions in representative samples of 30 tissues/cow. Rectal palpation of the reproductive tracts once a week indicated that the corpora lutea were small in cows given zearalenone. There was a general trend to increased hemoglobin concentrations in cows given the larger doses of zearalenone. Zearalenone of and by itself does not seem to be an important factor in dairy cow health.

Effect of zearalenone on the fertility of virgin dairy heifers.

Eighteen cycling, virgin, Holstein heifers daily were given 250 mg of 99% purified zearalenone in a gelatin capsule orally, and 18 controls were given an empty gelatin capsule once a day. The study lasted through 1 non-breeding estrous cycle and the next 2 consecutive estrous cycles during which the 36 heifers were bred, using artificial insemination. Serum concentrations of progesterone and complete blood cell counts were determined throughout the study. The treated and control heifers had conception rates of 62% and 87%, respectively. There was no effect (P less than 0.05) on the serum concentration of progesterone or the complete blood cell counts. Three heifers, bred but not pregnant by the end of the study, were euthanatized and necropsied. The treated heifer did not have any zearalenone-attributable lesions, and there was no effect seen in the bone marrow smears. The remaining 33 heifers were sold as a herd, and the 31 pregnant heifers calved normally. There was no effect (P less than 0.05) on the sex ratio of the offspring, which were all clinically healthy. Zearalenone did lower the conception rate of the treated heifers (P less than 0.065).

The failure of purified T-2 mycotoxin to produce hemorrhaging in dairy cattle.

A Holstein cow was intubated with 182 mg of 97% pure T-2 toxin (0.44 mg/kg of body weight) for 15 days. A dairy ration containing 50 mg/kg (50 ppm) of T-2 toxin was refused. A calf, born four days after onset of maternal treatment, was intubated with 26.2 mg of purified T-2 toxin (0.6 mg/kg of body weight) for seven consecutive days and then on alternate days for a total of 16 days. The calf was severely affected clinically by the T-2 toxin. The T-2 toxin failed to cause bovine hemorrhagic syndrome in either animal. Unspecific gastrointestinal lesions were noted in the cow but none were detected in the calf. In the calf, severe depression, hindquarter ataxia, knuckling of the rear feet, listlessness and anorexia were caused by the T-2 toxin.

Transmission of radioactivity into eggs from laying hens (Gallus domesticus) administered tritium labeled T-2 toxin.

The transmission of radioactivity into eggs from laying hens gastric-intubated with a single or multiple dose of 3-[3H]-T-2 toxin was investigated. In single dosed birds, the maximum radioactivity in eggs occurred at 24 hr after dosing; the yolk and white contained .04 and .13% of the administered radioactivity, respectively. In multiple-dosed birds given 8 consecutive daily doses, the radioactivity in the yolk increased with each dose, whereas the radioactivity in the white increased rapidly until the 3rd dose and thereafter remained constant. In both single- and multiple-dosed birds, the specific radioactivity of the white was greater than that of the yolk. The amount of residue transmitted into an egg in birds intubated daily with 1 mg T-2/kg for 8-consecutive days equivalent to 1.6 ppm dietary T-2) was about .9 microgram (based on specific radioactivity).

Acute toxicity of 12,13-epoxytrichothecenes in one-day-old broiler chicks.

Acute toxic effects of several 12,13-epoxytrichothecenes were investigated in 1-day-old broiler chicks by single oral doses. The 7-day median lethal dose values of purified 8-acetylneosolaniol, diacetoxyscirpenol, T-2 toxin, HT-2 toxin, neosolaniol, deacetyl-HT-2 toxin, and T-2 tetraol were 3.22 +/- 0.26, 3.82 +/- 0.40, 4.97 +/- 0.44, 7.22 +/- 0.39, 24.87 +/- 2.64, 30.18 +/- 7.53 (incomplete value), and 33.79 +/- 5.39 mg/kg of body weight, respectively. Deaths occurred during the 8- to 60-h period after dosing with the tested trichothecenes. Within 4 to 10 h after dosing, inappetence, asthenia, diarrhea, and coma generally developed. Sublethal doses of each toxin decreased feed consumption and weight gain proportionally with the amounts of toxins administered. These results demonstrate that the toxic potency of 12,13-epoxytrichothecenes varies depending on the modification of side chains in the molecule.