Effects of mixed legume leaf powder supplementation on nutrient intake, blood metabolites, and reproductive hormone profiles in buffaloes

Background and Aim: Buffaloes play a vital role in tropical livestock systems, yet their productivity and reproductive efficiency are strongly influenced by nutritional management. Protein- and amino acid-rich legume forages have been widely proposed as sustainable dietary supplements to enhance metabolic and reproductive performance. However, evidence regarding their effectiveness in animals maintained under adequate nutritional status remains limited. Therefore, this study evaluated the effects of supplementation with mixed legume leaf powder on nutrient intake, digestibility, blood metabolites, growth performance, and reproductive hormone profiles in female buffaloes. Materials and Methods: Sixteen female swamp buffaloes (initial body weight 532.85 ± 85.58 kg) were assigned to control and treatment groups in a completely randomized design. The control group received a diet of Napier grass and concentrate, whereas the treatment group received an additional 10% mixed legume leaf powder comprising Gliricidia sepium, Calliandra calothyrsus, and Leucaena leucocephala (1:1:1). Feed intake, apparent digestibility, and amino acid intake were measured. Blood samples were collected to determine glucose and urea concentrations. Reproductive hormone profiles (progesterone and estrogen) were monitored throughout the estrous cycle. Data were analyzed using analysis of variance and linear mixed-effects models. Results: Supplementation with mixed legume leaf powder significantly increased intake of dry matter, organic matter, crude protein, gross energy, and most amino acids (p < 0.05). Digestibility of crude protein, as well as digested intake of dry matter and organic matter, was also significantly improved (p < 0.05). However, serum urea and glucose concentrations were not affected by dietary treatment (p > 0.05). Similarly, progesterone and estrogen profiles across the estrous cycle showed no significant differences between control and treatment groups (p > 0.05). Body weight gain did not improve significantly despite increased nutrient intake. Conclusion: Mixed legume leaf powder supplementation enhances nutrient intake, amino acid supply, and digestibility in female buffaloes but does not influence metabolic status, growth performance, or reproductive hormone dynamics under adequate nutritional conditions. These findings suggest that additional protein supplementation may provide limited benefits when animals are already maintained under optimal feeding and body condition. Further studies under nutrient-deficient conditions and over longer durations are recommended to clarify potential reproductive advantages.