Oral Administration of Moringa oleifera or Its Nanoemulsion Ameliorates Testicular Hemodynamics, Testosterone Concentration, Semen Quality, and Total Antioxidant Capacity in Heat-Stressed Goat Bucks

This study aimed to investigate the novel application of unformulated Moringa oleifera (MOR) and its nanoemulsion (MO-NE) in mitigating the adverse impacts of thermal stress on testicular hemodynamics, the antioxidant profile, and semen characteristics in bucks. Fifteen sexually mature bucks were randomly assigned to three equal groups and treated orally once daily for 8 weeks: (1) the control group (n = 5; CON) received a basal diet only; (2) the MOR group (n = 5; MOR) received the basal diet supplemented with 40 mg/kg BW of unformulated MOR orally; and (3) the moringa nanoemulsion group (n = 5; MO-NE) received the basal diet supplemented with 4 mg/kg BW of MO-NE orally. Testicular ultrasound, semen, and blood parameters were evaluated weekly across 8 weeks (1–8 week) during summer heat-stress (HS) trial (temperature-humidity index (THI) = 76.70–79.54), following a two-week (week-1 and week-2) pre-heat stress winter baseline in February. In the MO-NE group, testicular Doppler indices (resistive index, pulsatility index, and systolic/diastolic ratio) significantly decreased (p < 0.05) from weeks 2–8, concurrent with increased (p < 0.05) total antioxidant capacity, catalase enzyme, superoxide dismutase, and glutathione peroxidase. Furthermore, MO-NE achieved the highest (p < 0.05) testosterone and nitric oxide levels (weeks 2–8), improving sperm motility, sperm viability, acrosome integrity, and normal morphology (weeks 2–8), alongside sperm cell concentration at weeks 5 and 8. In conclusion, MO-NE intervention serves as a viable strategy to mitigate HS in bucks, successfully restoring core reproductive functions, including testicular perfusion and sperm quality parameters.