Effects of replacing soybean meal with powdered or pelleted black soldier fly larvae on nutrient digestibility and rumen fermentation in Thai native beef cattle

Abstract

Objective: This study evaluated the effects of replacing soybean meal (SBM) with black soldier fly larvae (BSFL) in powdered and pelleted forms on feed intake, rumen fermenta tion, and nutrient digestibility in Thai native beef cattle. Methods: Four male Thai native beef cattle (3–3.5 years old; 370±20.0 kg body weight) were assigned to a 4×4 Latin square design to evaluate the effects of replacing SBM with BSFL in the concentrate portion of the diet. The dietary treatments were: T1, control diet with SBM as the sole protein source; T2, 50% of SBM replaced with powdered BSFL; T3, 25% of SBM replaced with pelleted BSFL; and T4, 75% of SBM replaced with pelleted BSFL. Results: Replacing SBM with BSFL had no significant effect on dry matter (DM) intake, ruminal pH, ammonia-nitrogen, or volatile fatty acid concentrations (p>0.05). Neutral detergent fiber intake was significantly higher in cattle fed the diet containing 75% pelleted BSFL compared to those fed 25% pelleted BSFL (p<0.01). Crude protein digestibility improved overall in BSFL-supplemented groups compared to the control (p<0.01). The highest DM digestibility was observed at 25% pelleted BSFL, significantly higher than at 75% inclusion (p<0.05). At 4 hours post-feeding, blood urea nitrogen concentration was significantly lower in cattle fed the 75% pelleted BSFL diet compared to those fed 25% pelleted BSFL (p<0.05). Protozoal populations, total volatile fatty acid concentrations, and the volatile fatty acid profile did not differ significantly among treatments (p>0.05). Conclusion: Replacing SBM with BSFL, particularly at 25% in pelleted form, improves nutrient digestibility without impairing rumen fermentation, supporting its potential as a functional protein source in ruminant diets.