Corn fermented protein in production diets for pacific white legged shrimp Litopenaeus vannamei: Improved growth performance, health status and resistance to infection

Abstract

Two separate trials were conducted to evaluate the use of a novel Corn Fermented Protein (CFP) on growth performance and feed utilization of Pacific white legged shrimp Litopenaeus vannamei in out-door pond conditions as well an independent pathogen challenge (Vibrio harveyi) test under controlled conditions following an internal feeding trial with varying inclusions of CFP. In out-door ponds, the 12% inclusion level of CFP to completely replace the use of corn gluten meal (CGM) was shown to support shrimp growth in the pond that was historically heavily infected with pathogen, including white spot syndrome virus (WSSV) and acute hepatopancreatic necrosis disease (AHPND). In an indoor growth trial parallel with the pond challenge study, CFP at the level of 6%, 12% and 18% at the expense of fish meal (FM), soybean meal (SBM) and CGM were also able to improve growth and several related parameters such as final body weight, percentage weight gain and thermal growth coefficient (TGC). The feed conversion ratios (FCR) for shrimp fed with CFP were also lower compared to the shrimp fed without CFP. Numerically, despite no statistical difference, survivability, and total haemocyte count were also elevated for shrimp receiving CFP. The challenge test results showed that the mean cumulative survival rate of shrimp injected with V. harveyi at the dose of 5 × 104 CFU shrimp−1 were higher in the group of shrimp fed CFP compared to the control treatment. Values for mean phagocytosis activity were superior for fermented corn-fed shrimp. Meanwhile, haemocyte profiles remained uniform across treatments and phagocytic index was significantly reduced at 18% inclusion level of CFP. Phenoloxidase activity post-challenge with V. harveyi was elevated in shrimp fed CFP at all levels. These findings suggest that 6 – 12% inclusion of CFP can be utilized as a novel ingredient for shrimp feed. Advocating for functional ingredients with characteristics that can support health and welfare of intensively farmed shrimp will be of strategic importance in the future for sustainable production of shrimp under intensive conditions.