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

Abstract

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.