Effects of replacing dietary fish meal with Clostridium autoethanogenum protein on growth and flesh quality of Pacific white shrimp (Litopenaeus vannamei)

This study evaluated the effects of replacing fish meal (FM) with Clostridium autoethanogenum protein (CAP) on growth and flesh quality of Pacific white shrimp, Litopenaeus vannamei. A control diet was designed to contain 560 g/kg FM, then 0%, 15%, 30%, 45%, 70% and 100% of dietary FM was replaced by CAP, referring to Con, CAP-15, CAP-30, CAP-45, CAP-70 and CAP-100, respectively. The six isoproteic and isolipidic diets were fed to shrimp (2.78 g) for 8 weeks. The increasing dietary CAP level negatively affected feed intake, weight gain and feed conversion ratio (P < 0.05). A negative linear tend was found between dietary CAP level and body surface redness, yellowness and flesh total collagen contents, n-3/n-6 PUFAs value and free flavor amino acids contents (P < 0.05). Both linear and quadratic trends were detected between flesh hardness, shear force, steaming loss, cooking loss and dietary CAP level (P < 0.05). In CAP-15 and CAP-30 groups, the above indexes presented the similar levels to the Con group (P > 0.05). Metabonomics analysis showed that the high replacement of FM with CAP affected the amino acids and fatty acids metabolism in flesh. In conclusion, in a basal diet containing 560 g/ kg FM, 30% dietary FM could be successfully replaced by CAP, while higher FM substitution decreased the growth and flesh quality of L. vannamei.