Curcumin as a natural modulator of semen quality in endangered Teressa goats in tropical island conditions

The present study was designed to evaluate the effect of curcumin supplementation in the semen extenders on the semen quality parameters of Teressa goat bucks. A total of 25 semen samples were collected from six healthy bucks and processed for liquid storage. Spermatozoa were standardized to a concentration of 4 × 10⁸/mL and incubated with curcumin at concentrations of 1 mM, 2 mM, and 4 mM, corresponding to Groups II, III, and IV, respectively. A control group (Group I) without curcumin served as the baseline for comparison. The semen samples were stored at refrigeration temperature and assessed at multiple time points up to 72 h for various semen quality parameters which included the sperm viability, motility, total sperm abnormalities, acrosomal integrity, plasma membrane integrity, nuclear integrity and biochemical markers such as intracellular enzymatic leakage [alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH)], cholesterol efflux, malondialdehyde (MDA) and total antioxidant capacity (TAC) levels. The present study results revealed that the semen samples treated with 2 mM curcumin (Group III) showed significantly (P < 0.05) higher viability, motility, acrosomal integrity, plasma membrane integrity, nuclear integrity and TAC. Concurrently, Group III also exhibited significantly (P < 0.05) lower total sperm abnormalities, leakage of intracellular enzymes (ALT, AST and LDH), MDA production and cholesterol efflux as compared to those in the control and other curcumin-treated groups. Trends across the treatment groups showed a progressive improvement in the semen quality and antioxidant concentrations from Group I to Group III, followed by a decline in Group IV (4 mM) which indicated a dose-dependent effect. Therefore, 2 mM curcumin was identified as the optimal concentration of curcumin for enhancing the semen quality and preserving the functional and structural integrity of spermatozoa during liquid storage in the Teressa goats.