This study aimed to evaluate the effects of the inclusion of unsaturated fatty acid (UFA) sources on the nutrient intake, apparent digestibility, ruminal fermentation, and feeding behavior in diets for buffaloes. Four castrated Murrah buffaloes with approximately 24 months of age and an initial average body weight of 351 ± 15 kg were randomly assigned to a 4 × 4 Latin square experiment, containing the following diets: (1) control (CON): control diet based on soybean meal and ground corn, (2) soybean oil (SO): dietary inclusion of 2.20% (DM basis), (3) whole raw soybean (WRS): dietary inclusion of 16.0%, and (4) calcium salts of FA (CSFA): dietary inclusion of 2.60%. There was an effect of diets in ether extract intake among buffaloes fed UFA and CON diets, and among buffaloes fed CSFA and WRS diets (P < 0.05). Diets containing UFA sources provided higher EE digestibility (P < 0.05). Buffaloes fed WRS had higher rumen pH values than animals fed the CSFA diet (P < 0.05). Supplementation of UFA sources decreased the molar concentrations of short-chain fatty acids (P < 0.05). Diets influenced the times spent in chewing, idling, and the rumination efficiencies of DM and NDF (P < 0.05). The supplementation with WRS, SO, and CSFA does not negatively affect intake, digestion, ruminal metabolism, and feeding behavior. The WRS as a fat supplement source decreases dietary costs by replacing ground corn and soybean meal simultaneously compared to other fat sources used. Nevertheless, whole and raw soybean in buffaloes' diet can reduce chewing and rumination activity.
Keywords: Buffalo; Calcium salts; Protected fat; Rumen fermentation; Rumen pH.