مشخصات پژوهش

This study evaluated the effects of three probiotic strains (Bacillus subtilis, Lactobacillus plantarum, and Pediococcus acidilactici) on growth performance, survival rate, digestive physiology, antioxidant defense, fatty acid composition, and intestinal development of Sobaity seabream (Sparidentex hasta) larvae over a 40-day rearing period. Larvae were assigned to five treatments: Control, Bacillus (Bac), Lactobacillus (Lac), Pediococcus (Pedi), and a mixed-probiotic group (Mix), and were fed rotifers and Artemia enriched with the corresponding probiotics. Probiotic supplementation significantly influenced larval performance and physiological markers across all treatments (p < 0.05). The Bac group exhibited significantly higher growth performance, reaching 15.62 ± 0.62 mm in length and 1072.13 ± 51.5 mg in weight by 40 days post-hatch (p < 0.05). The Lac group also achieved a high final weight (1103.7 ± 153 mg; p < 0.05), albeit with a lower standard length. Although the Pedi group demonstrated the highest digestive enzyme activity (e.g., lipase 1.39 ± 0.01 nmol/mg protein; p < 0.05) and antioxidant status (e.g., SOD 2.8 ± 0.02 nmol/mg protein; p < 0.05), these physiological improvements were not directly associated with superior growth performance. The Mixed-strain group recorded the highest crude protein (21.41 ± 1.06%) and lipid (3.1 ± 0.87%) levels at 40 dph (p < 0.05), despite exhibiting suboptimal weight gain. Fatty acid analysis revealed that Bac treatment resulted in the highest DHA (1.91 ± 0.24%) and EPA (3.37 ± 0.07%) concentrations and the most favorable n-3/n-6 ratio (p < 0.05). Histological analysis revealed significant differences in intestinal morphology at 40 dph (p < 0.05). The highest mucosal layer thickness (MLT) was observed in the Lac (12.23 ± 2.1 μm) group (p < 0.05), whereas the lowest value occurred in the Pedi group (4.67 ± 0.96 μm) (p < 0.05). Crypt depth (CD) was greatest in the Bac group (28.27 ± 2.88 μm), followed by Lac (16.71 ± 1.9 μm