Growth performance and ultrasonographic body composition responses in lambs receiving Spirulina

This study investigated the effects of oral Spirulina (Arthrospira platensis) administration on growth performance, rumen fermentation, blood biochemical parameters, and in vivo body composition in growing Barki lambs. Thirty male lambs (1–1.2 years old; 42.2 ± 1.9 kg) were randomly assigned to a control group fed the basal diet or two treatment groups receiving the basal diet with Spirulina at 0.1 (SPP1) or 0.2 g/kg body weight (SPP2) for 60 days. Longitudinal ultrasonography was applied to monitor changes in the longissimus dorsi muscle and fat deposition. Spirulina administration improved growth performance in a dose-dependent manner (p < 0.05). Rumen fermentation was enhanced in SPP2 lambs, as indicated by higher total volatile fatty acids and lower ammonia-N levels (p < 0.05). Blood biochemical analysis showed increased total protein concentrations and antioxidant capacity, with reduced urea and glucose levels in SPP2 lambs (p < 0.05). Ultrasound measurements showed dose-dependent increases in longissimus dorsi muscle area, perimeter, depth, and compactness, as well as backfat thickness, intramuscular fat, and fat-to-muscle ratio (p < 0.01). In conclusion, oral Spirulina at 0.2 g/kg BW enhanced growth performance, blood biochemical indicators, and in vivo body composition. Integrating Spirulina administration with longitudinal ultrasonography may provide a practical, non-invasive approach to monitor tissue development in small ruminants.