Oral Intervention with Eurycoma longifolia and L-arginine to Male Rabbits Boosts Semen Characteristics, Metabolic Attributes, Reproductive Hormones, and Fertility Outcomes

This study aimed to explore the effects of oral swallowing of Eurycoma longifolia (EL) and L-Arginine (LA) on fertility outcomes in male rabbits. Two stages were applied to conduct the study. Stage I: Thirty-two mature bucks (average 6-8 months of age and weighing 3180±11.20g) were used in an experiment for 7 weeks, followed by 8 weeks for semen collection and analysis. Males were subdivided into four equal groups (n=8/G). Group G1, serving as the control (C), was given distilled water; Group G2 (EL) was provided with 200 mg EL/kg BW every other day, Group G3 (LA) was given 250 mg LA/kg BW, and Group G4 (ELA) was given a combination of the two additives. Stage II: Thirty-two mature nulliparous does (aged 6 months and weighing 3050±20.7g) were randomly allotted to be inseminated with the male’s semen (30-40×106 motile sperm) of each treatment (n=8/G). Also, blood was collected at the conclusion of the treatment, and plasma was harvested for analysis. Treatments improved libido, ejaculate volume, progressive motility, sperm concentration, and livability compared with the control. Also, treatments reduced (P<0.05) cholesterol, LDL, TG, and MDA; however, elevated HDL and TAC. Additionally, treatments increased testosterone, LH, and FSH, but decreased E2 in males. Fecundity, fertility, Litter size, and newborn viability were higher in treated than in control does. In conclusion, supplementing rabbit bucks with a mixture of Eurycoma longifolia and L-arginine improved the health status, semen quality of rabbit bucks and resulted in a higher crop of live kids.