biostudies-literatureUnknown134(8)Singha KPThe effects of high plant-based proteins (PP) used as alternative protein sources in aquafeeds on muscle cellularity and myogenic factors of rainbow trout, <i>Oncorhynchus mykiss</i>, remain unclear. This study explored muscle fibre growth phases and the impact of two additive mixtures (A) in high-PP diets on muscle physiology. Over a seven-month trial, 2000 fish (2·22 g) were divided into four groups (five replicates each) and fed isonitrogenous (fry, 46 %; fingerling, 44 %; and grow-out, 42 % crude protein) and isolipidic (20 % lipid) diets: control (30 % fishmeal), PP, PP + A1 (krill meal, taurine, selenium) and PP + A2 (proline, hydroxyproline, vitamin C). Sampling for muscle histology and myogenic gene expression was conducted at ten sampling points from Day 0 to Day 214. Muscle histoThe British journal of nutrition617-633https://www.ebi.ac.uk/biostudies/studies/S-EPMC12722011biostudies-literatureMuscle hyperplasia and hypertrophy dynamics in rainbow trout (<i>Oncorhynchus mykiss</i>): impact of high plant-based protein and additive mixtures on muscle physiology.PMC12722011Kumar VPhelps MOverturf KSingha KPfalseMuscle hyperplasia and hypertrophy dynamics in rainbow trout (<i>Oncorhynchus mykiss</i>): impact of high plant-based protein and additive mixtures on muscle physiology.The effects of high plant-based proteins (PP) used as alternative protein sources in aquafeeds on muscle cellularity and myogenic factors of rainbow trout, <i>Oncorhynchus mykiss</i>, remain unclear. This study explored muscle fibre growth phases and the impact of two additive mixtures (A) in high-PP diets on muscle physiology. Over a seven-month trial, 2000 fish (2·22 g) were divided into four groups (five replicates each) and fed isonitrogenous (fry, 46 %; fingerling, 44 %; and grow-out, 42 % crude protein) and isolipidic (20 % lipid) diets: control (30 % fishmeal), PP, PP + A1 (krill meal, taurine, selenium) and PP + A2 (proline, hydroxyproline, vitamin C). Sampling for muscle histology and myogenic gene expression was conducted at ten sampling points from Day 0 to Day 214. Muscle histo2025-01-01T00:00:00Z2025 Oct2026-06-06T05:26:12.926Z2026-05-26T03:12:25.191ZS-EPMC127220114098359510.1017/S0007114525105175