In vitro and in vivo effects of Acacia mearnsii De Wild extract for cyathostomin control in horses

Introduction

Anthelmintic resistance has led to the use of organic extracts as alternative methods of parasite control.

Objectives

The study aimed to assess the effects of Acacia mearnsii extract (tannin) on the control of cyathostomins in horses, both in vitro and in vivo.

Materials and methods

Thirty Pantaneiro horses naturally infected with cyathostomins were sourced from two distinct farms, designated as Farms A and B. At the start of the study, all third-stage larvae were cyathostomins, and an egg hatchability test (EHT) was performed using fecal samples from horses on both farms. Two randomized 28-day field studies were conducted for the fecal egg count reduction test (FECRT) with evaluations on days 0, 7, 14, 21, and 28. On days 0 and 28, body weight (BW), body condition score (BCS), and blood samples for hematological and biochemical analysis were also collected. The horses diet included panicum grass pasture, 1 kg of concentrate, 40 g of liquid sugarcane molasses (Control), and 25 g of A. mearnsii extract.

Results

The EC50 values were 13.2 mg/mL (95 % confidence interval [CI]: 11.8–14.7 mg/mL) and 14.9 mg/mL (95 % CI: 13.3–16.9 mg/mL) for Farms A and B, respectively. The FECRT showed no effect (P > 0.05) between the control and treated groups, with mean values of 3.09% and 3.18%, respectively. Blood and hematological parameters also showed no differences (P > 0.05) between treatments.

Conclusion

The tannin extract reduced egg hatchability in vitro, but did not lower fecal egg counts in naturally infected horses during the in vivo trial.