Long term exposure to T-2 Fusarium mycotoxin fails to alter luteal function, follicular activity and embryo recovery in mares.

The research investigates the impact of long-term administration of a toxin called T-2 on Trotter mares’ reproductive system, concluding that the toxin does not adversely affect ovarian activity, fertilization, or egg transportation within their bodies.

Methodology

• The study involved six Trotter mares during the summer and early autumn.
• After a complete oestrous cycle (named Cycle 1), each mare received 7 mg of purified T-2 toxin daily (1 mg/ml in ethyl alcohol) starting on Day 10 following ovulation in the second cycle, named Cycle 2.
• They were continuously exposed to this toxin for between 32 to 40 days until Day 7 of the fourth cycle, termed Cycle 4.

Observations

• Throughout the exposure period, all the mares maintained good physical condition.
• However, 3 of the mares developed skin lesions around their mouths.

Findings

• Intake of the toxin did not influence the length of the interovulatory interval, luteal phase duration, or follicular phase duration.
• The toxin did not cause any effects on the horses’ peripheral plasma progesterone profiles or follicular kinetics, including growth rate, maximum size of ovulatory follicles, maximum number of follicles, and the time when the number of follicles larger than 1 and 2 cm first increased.
• For five mares, uterine flushing was attempted, which resulted in the recovery of three embryos, reflecting a 60% success rate.
• These embryos were of standard size and form, with one transferred nonsurgically to a recipient mare. Although a conceptus initially developed, it later died and was reabsorbed.

Conclusion

• The administration of 7 mg/day T-2 toxin to fit mares does not seem to have a negative impact on ovarian activity, fertilisation, or oviductal transport, based on the study’s observations.