170 Effects of feeding male goats with sericea lespedeza and black seed meal on the quality of their cooled semen

Sericea lespedeza (SL), a perennial legume high in condensed tannins, is recognised for its anthelmintic properties and role in enhancing livestock health. Black seed meal (BSM) is renowned for its strong antioxidant and anti-inflammatory properties. Previous studies have revealed the positive impacts of SL and BSM on rabbit male fertility. However, the effects of these substances on goat reproduction remain largely unexplored. This study sought to assess the influence of dietary supplementation with SL and BSM on fertility parameters and the quality of cooled semen in Spanish bucks. A total of 60 mature Spanish bucks were randomly allocated to four groups (15 animals per group), each receiving different dietary supplements: (1) SL, (2) SL+BSM, (3) alfalfa without deworming (naturally parasitized group), and (4) alfalfa with deworming. The dietary regimen consisted of a 60% pellet and 40% concentrate mix, provided over an 8-week period during the breeding season (October–November). Blood samples were taken at the end of weeks 1, 4, and 8 for testosterone analysis. Upon conclusion of the trial, the animals were slaughtered, and their testes and epididymides were collected for histopathological examination. Parameters like motility, viability, morphology (evaluated by eosin-nigrosin staining), and membrane integrity (assessed by the hypo-osmotic swelling test, HOS) of the epididymal spermatozoa were assessed immediately after semen collection (0 h) and after cooling at 5°C for 24 and 48 h. Data were statistically analysed using one-way analysis of variance. Overall, testosterone levels showed no significant difference (P ≤ 0.05) between treatments. However, a noteworthy time-dependent difference within treatments was observed. The group receiving both SL and BSM presented the highest average testosterone level at week 4 compared with other groups. Sperm motility, viability, and membrane integrity decreased in all groups in a time-dependent manner after cooling, with the highest values at 0 h and the lowest values at 48 h post-cooling. Conversely, sperm abnormalities (such as broken tail, head without tail, misshapen heads) increased over time across all groups. Histopathological examination of the testes and epididymis showed significantly higher (P ≤ 0.05) instances of testicular degeneration and abnormalities in group 4 (fed with alfalfa and dewormed) compared with the other groups. These findings highlight the potential effect of dietary intervention on physiological parameters related to male fertility. However, the inconsistent effects across all parameters and time points indicate complexity in dietary influences on animal health and fertility. Despite the observed benefits, neither SL nor SL + BSM significantly improved the quality of cooled semen, suggesting the need for further research into the exact mechanisms by which these supplements may influence male goat fertility.