Effects of replacing fishmeal with soybean protein concentrate (SPC) on growth, blood biochemical indexes, non-specific immune enzyme activity, and nutrient apparent digestibility for juvenile Litopenaeus vannamei

An 8-week feeding trial was conducted to investigate the effects of dietary soy protein concentrate (SPC) levels on growth, blood biochemical indexes, non-specific immune enzyme activity, and nutrient apparent digestibility for juvenile Litopenaeus vannamei (initial weight 0.44 ± 0.002 g). They were formulated by replacing 0% (the control), 10%, 20%, 30%, 40%, 60%, and 80% of fish meal (FM) protein with SPC (designed FM, S11, S22, S33, S44, S55, and S66, respectively). With the replacement level of SPC in the diet was higher than 30%, weight gain (WG) and specific growth rate (SGR) for juvenile Litopenaeus vannamei significantly decreased (P < 0.05) with SPC increasing, but feed conversion ratio (FCR) significantly increased (P < 0.05). When the replacement level was above 40%, the protein efficiency ratio (PER), survival rate (SR), apparent digestibility of dry matter, and energy significantly decreased (P < 0.05). On the contrary, the content of triglyceride glucose (TG) in serum was increased significantly (P < 0.05). Apparent digestibility for crude protein and total lipid were significantly higher at higher fishmeal inclusion (0 and 10% SPC replacement) and significantly lower at lower fishmeal inclusion (< 70%) (P < 0.05). In conclusion, with reference to all the parameters, SPC can be used to replace up to 30% of fishmeal protein in shrimp feeds and so the total fishmeal exceeds 70% be used to cater to shrimps’ dietary needs.