Effects of replacing fishmeal with dietary soybean protein concentrate (SPC) on growth, serum biochemical indices, and antioxidative functions for juvenile shrimp Litopenaeus vannamei

This experiment was conducted to assess the possibility of replacing fishmeal (FM) with Soybean Protein Concentrate (SPC) at different levels (Diet 1 (0%), Diet 2 (3.08%), Diet 3 (6.16%), Diet 4 (9.24%), Diet 5 (12.32%), Diet 6 (15.40%), Diet 7 (18.48%)) as well as its effects on growth, serum biochemical indices and antioxidant activities, body composition, histology, intestinal flora and disease resistance in Litopaeneaus vannamei. There were three replicates in each group in the experiment (Initial mean weight = 0.23 +/- 0.00 g) and were fed their respective diets for 8 weeks. Growth performance in Diet 6 compared to the Diet 1, significantly increased (P < 0.05) and the survival rate ranged from 90% to 95%. No significant difference was observed among the groups in terms of crude protein, moisture, and ash content. There was an increase in serum acid phosphatase, alkaline phosphatase, High-Density Lipoprotein Cholesterol, Total Antioxidant capacity, Glutathione peroxidase. Significant decreases (P < 0.05) in Glucose and Total Cholesterol were observed in the shrimp. Also, no significant difference was observed in serum Alanine Aminotransferase, and Total protein (P >0.05). Histology of the intestine showed Villus height and intestinal wall thickness significantly increased (P < 0.05) with increasing inclusion of SPC, 15.40% had the highest value. In intestinal flora, replacement of FM with SPC in the shrimp intestine had positive effects on a number of beneficial bacteria such as Pseudoalteromonadaceae among the treatment groups with 15.40% having the highest value as compared to 0% at the family level. Furthermore, diversity indices and richness estimate increased with increasing SPC levels. Disease resistance was increased in shrimp among treatment groups, 15.40% recording the lowest mortality percentage of 40.22% after the challenge test. In conclusion, with reference to all the parameters, replacement of FM with SPC at 15.40% could be used to cater for shrimps' dietary needs.