Purple bacteria as added-value protein ingredient in shrimp feed:Litopenaeus vannameigrowth performance, and tolerance againstVibrioand ammonia stress

Purple non-sulfur bacteria (PNSB) biomass is an emerging alternative protein source, yet research of PNSB as added-value protein ingredient is limited. This research aimed to study the use of PNSB as protein source for shrimp and investigate the shrimp’s tolerance against Vibrio and ammonia stress. A 28-day shrimp feeding trial was performed with Rhodopseudomonas palustris, Rhodobacter capsulatus and a mixed PNSB culture. PNSB contained in feed (5-10% protein substitution) resulted in 5-26% higher individual weights, better feed conversions ratios (1.2-1.7) compared to commercial feed (1.7) and tolerance against ammonia. In parallel, the effect of PNSB on the growth of Vibrio pathogens was tested in vitro. The species Rps. palustris, Rb. capsulatus, Rb. sphaeroides, Rhodospirillum rubrum and Afifella marina suppressed the growth of Vibrio parahaemolyticus TW01 and V. campbellii LMG 21363. Overall, this study demonstrated the potential of PNSB as nutritious feed ingredient for shrimp. This can contribute to circular economy, as PNSB enable resource recovery from wastewater. Abstract Figure Graphical abstract Highlights Purple non-sulfur bacteria (PNSB) enhance the growth performance of shrimp PNSB-fed shrimp has better feed conversion ratio, growth rate and weight gain Shrimp fed with Rhodopseudomonas are more resistance against ammonia stress Freeze-dried and live PNSB inhibit Vibrio pathogens in vitro