Fig 1 -

Polynomial regression analysis (Pn = 9).</p

Formulation and composition of the basal diet.

Soybean lecithin (SBL) is usually added to aquafeed as a lipid source because aquatic animals cannot synthesize phospholipids. Hence, this study aimed to investigate the role of SBL on the growth, nutrient consumption, digestive enzyme activity, blood parameters, and antioxidant capability of striped catfish. The fish were fed on five experimental diets with five grading levels of SBL (0, 2, 4, 6, and 8%) for 60 days. The final weight, weight gain, specific growth rate, feed intake, and protein efficiency ratio were markedly higher in striped catfish treated with 2–4% SBL than the control level (0% SBL). However, the lowest feed conversion ratio was in the fish-fed groups of 4–6% SBL. The carcass lipid content was significantly higher in fish fed 2–4% SBL compared to the control level (0% SBL). The lipase, amylase, and protease activities were significantly increased in the fish fed 2–6% SBL compared to 0% SBL-fed group. The gradually increased levels of SBL improved the structural appearance and increased the intestinal villi length and branching appearance. The triglycerides and total cholesterol were increased in the fish fed with 4, 6, and 8% compared to the control level, with the highest being in the fish fed with 8%. The lysozyme activity was higher in the fish fed with 2, 4, and 6% of SBL compared to the control level, with higher activity in the fish fed with 2 and 4% than 6%. Superoxide dismutase, glutathione peroxidase, and catalase activities were increased in the fish fed with 2, 4, and 6% SBL. The malondialdehyde level was lower in the fish fed with 4–6% SBL compared to the control level. The regression analysis revealed that the optimum dose of SBL is required at 3.65–4.42% for better productivity and health performances in striped catfish.</div

Blood immunity and antioxidative responses of striped catfish fed dietary soybean lecithin for 60 days.

Blood immunity and antioxidative responses of striped catfish fed dietary soybean lecithin for 60 days.</p

Growth performance of striped catfish fed dietary soybean lecithin for 60 days.

Growth performance of striped catfish fed dietary soybean lecithin for 60 days.</p

Carcass composition of striped catfish fed dietary soybean lecithin for 60 days.

Carcass composition of striped catfish fed dietary soybean lecithin for 60 days.</p

Blood biochemical indices of striped catfish fed dietary soybean lecithin for 60 days.

Blood biochemical indices of striped catfish fed dietary soybean lecithin for 60 days.</p

Fig 2 -

Histomorphology of the middle intestine of striped catfish in the control fish (A; 0%) and gradually increased levels of soybean lecithin (B, C, D, E; 2, 4, 6, 8% respectively) showing evident enrichment and branching of intestinal villi (blue arrowhead) by increased levels of soybean lecithin in the supplemented diet. Stain H&E. Bar = 100 μm.</p

S1 Dataset -

Soybean lecithin (SBL) is usually added to aquafeed as a lipid source because aquatic animals cannot synthesize phospholipids. Hence, this study aimed to investigate the role of SBL on the growth, nutrient consumption, digestive enzyme activity, blood parameters, and antioxidant capability of striped catfish. The fish were fed on five experimental diets with five grading levels of SBL (0, 2, 4, 6, and 8%) for 60 days. The final weight, weight gain, specific growth rate, feed intake, and protein efficiency ratio were markedly higher in striped catfish treated with 2–4% SBL than the control level (0% SBL). However, the lowest feed conversion ratio was in the fish-fed groups of 4–6% SBL. The carcass lipid content was significantly higher in fish fed 2–4% SBL compared to the control level (0% SBL). The lipase, amylase, and protease activities were significantly increased in the fish fed 2–6% SBL compared to 0% SBL-fed group. The gradually increased levels of SBL improved the structural appearance and increased the intestinal villi length and branching appearance. The triglycerides and total cholesterol were increased in the fish fed with 4, 6, and 8% compared to the control level, with the highest being in the fish fed with 8%. The lysozyme activity was higher in the fish fed with 2, 4, and 6% of SBL compared to the control level, with higher activity in the fish fed with 2 and 4% than 6%. Superoxide dismutase, glutathione peroxidase, and catalase activities were increased in the fish fed with 2, 4, and 6% SBL. The malondialdehyde level was lower in the fish fed with 4–6% SBL compared to the control level. The regression analysis revealed that the optimum dose of SBL is required at 3.65–4.42% for better productivity and health performances in striped catfish.</div

Digestive enzyme activity of striped catfish fed dietary soybean lecithin for 60 days.

Digestive enzyme activity of striped catfish fed dietary soybean lecithin for 60 days.</p