Passive acoustic feeders as a tool to assess feed response and growth in shrimp pond production

Shrimp production has been one of the most important sectors of aquaculture for the last few decades for both its market value and consumer acceptance. The majority of shrimp feeding protocols in typical production setups rely on a combination of feed trays and predetermined feed plans which do not account for real-time consumption or feed preferences. However, for the last decade, the development of passive acoustic monitoring has allowed a much more direct measurement of shrimp feed intake by capturing and integrating clicking sounds produced by shrimp while eating. Integrating acoustic responses with automated feeding systems has allowed the development of on-demand feeding systems for shrimp. Hence, this technology is a potential tool to help understand feed preferences when the feeding protocol is based on real-time demand for feed rather than predetermined quantities. Building on previous research, the goal of this trial was to use passive feedback acoustic feeders as a tool to evaluate if shrimp prefer diets with different protein sources when given the option to eat as much as requested. A 13-week trial was conducted in 16, 0.1-ha outdoor ponds, stocked at 30 shrimp/m 2 and equipped with the AQ1 acoustic feeding system. At day 45, the acoustic system was initiated, and four treatments were assigned with a 35% crude protein diet with different protein sources: all-plant, 8% poultry meal (PM), 8% fish meal (FM), and 12% FM. A second growth trial was conducted in 20, 800-L outdoor recirculating system with similar density (30 shrimp/tank), and shrimp were offered a predetermined feeding rate. We did not find statistical differences in any of the main production parameters. Results of this study indicate that shrimp did not clearly favor a particular diet. This suggests that, irrespective of ingredient matrix, a well-balanced feed will produce suitable growth even when shrimp are allowed to determine their feed intake. The use of acoustic feeders opens the door for nutrition research in which the shrimp are fed on demand.