Comparative Impact of Selenium Selenite and Nano-Selenium on Physiological Functions in Male Goat Kids

The present experiment was conducted to study the effects of nano-selenium (Se-NP) supplementation on nutrient utilization, growth, immune responses, antioxidant status, and reproductive performance in male goat kids over a 150-day experimental period. Twenty-four growing male goats were randomly allocated to three groups: control (T1), and two treatment groups receiving dietary Se-NP at graded levels (T2-0.15 ppm and T3-0.30 ppm). Dry matter intake (DMI), nutrient digestibility, and the plane of nutrition remained statistically comparable (p > 0.05) across all groups, indicating no adverse effect of Se-NP on feed acceptance or digestion. Growth performance metrics including average daily body weight gain and feed conversion ratio were also unaffected by the treatments. Haematological and serum biochemical parameters, including glucose, total protein, and creatinine, remained within normal physiological limits, though significant day-wise variations (p < 0.05) were witnessed in glucose, cholesterol, total protein and creatinine. Antioxidant enzyme activity revealed a marked increase (p < 0.01) in Glutathione peroxidase (GPx) activity in T3(22.12 ± 2.21) and T2(11.99 ± 0.93), suggesting enhanced oxidative defence, while Superoxide dismutase (SOD) and Catalase (CAT) activities were unchanged. Notably, serum Triiodothyronine (T3) concentration increased significantly (p < 0.05) in T3(4.32 ± 0.24) and T2(4.21 ± 0.23) groups, accompanied by a reduction in Thyroxin (T4) and T4:T3 ratios, indicating potential modulation of peripheral thyroid hormone metabolism. Immune profiling demonstrated enhanced humoral (p < 0.05) and cell-mediated immune responses (p < 0.01) in Se-NP groups, particularly T3, as evidenced by higher haemagglutination titres and delayed-type hypersensitivity reactions. Reproductive assessment showed no differences in scrotal size; however, sperm quality parameters-mass motility, live sperm percentage, and hypo-osmotic swelling test response-were significantly improved (p < 0.01) in Se-NP supplemented goats. In conclusion, Se-NP supplementation, especially at higher levels (T3), positively influenced antioxidant status, immune competence, and seminal quality without compromising growth or metabolic health, demonstrating its potential as a functional micronutrient to enhance reproductive and immunological resilience in male goats.