Postprandial Bioavailability and Efficacy of Recombinant Bovine β-lactoglobulin for Resistance Training-Induced Skeletal Muscle Adaptation in Young Adults.

Introduction: Increasing concerns surrounding the environmental impact of animal- and plant-derived proteins warrants further investigations of alternative protein sources and their efficacy for supporting skeletal muscle anabolism. Herein, the postprandial amino acid bioavailability of a novel protein derived from recombinant bovine β-lactoglobulin (rBLG) was determined, alongside the muscle adaptive response to resistance exercise (RE) with rBLG, compared with dairy-derived whey (WHEY).

Methods: Healthy adults (n = 8; age: 24 ± 4 yrs; BMI: 23.5 ± 2.1 kg·m2) completed a randomised crossover study and ingested 0.3 g·kg body mass-1 of rBLG or WHEY with arterialised blood sampled in the fasted state and 240 min postprandially for measurement of plasma amino acid concentrations via UPLC-MS. In a separate double-blind randomised parallel group design, 24 healthy adults completed thrice-weekly lower-body RE for 8 weeks, with twice daily supplementation of 0.3 g·kg body mass-1 rBLG (n = 12; age: 23 ± 6 yrs; BMI: 25.6 ± 3.4 kg·m2) or WHEY (n = 12; age: 25 ± 6 yrs; BMI 25.1 ± 3.1 kg·m2). Training-induced changes in muscle strength and DEXA-derived leg lean body mass (LBM) were assessed.

Results: Plasma essential amino acid concentrations increased following protein ingestion (P < 0.001), but did not differ between trials (P = 0.554). Mean plasma leucine incremental area under curve was greater following rBLG compared to WHEY (mean diff(95%CI) 10727 (7738 to 13716) μmol·240 min·L-1P < 0.001). LBM and leg press 1RM increased following training (mean diff±SD: 0.65 ± 0.70 kg and 81.46 ± 42.81 kg, respectively; P < 0.05), with no differences between groups (P > 0.05). Training volume and daily protein intake did not differ between groups (P > 0.05 for all).

Conclusions: These data highlight rBLG, a sustainable, precision-engineered mimetic of dairy-derived whey as a novel protein source with the capacity to support skeletal muscle anabolism and exercise-induced remodelling similarly to dairy-derived whey.