Utilising feed effectors and automated feeders for semi-intensive pacific white shrimp (Litopenaeus vannamei) production

Feed effectors have been suggested to improve the efficiency of plant-based shrimp diets by increasing attractability and palatability. This research trial aimed to expand upon previous Pacific white shrimp (Litopenaeus vannamei) research involving plant-based diets, feed effectors and passive acoustic monitoring (PAM) in a laboratory setting by conducting a feed trial in outdoor semi-intensive ponds stocked at 30 shrimp/m2. A 13-week trial was conducted in sixteen 0.1-ha ponds equipped with PAM-integrated feeders, which allowed for demand-style feeding. Four soy-optimised diets, consisting of an 'all-plant' basal diet (AP) and three diets with an attractant (2% krill meal (KM), 2% squid meal (SM), 4% fish hydrolysate (FH)), were fed to the shrimp for a period of 74-75 days. Significantly more (p = 0.0131) of the FH diet was fed to the respective ponds than the KM and AP diets, suggesting that the addition of FH to soy-optimised diets increases the intensity of the feed response in shrimp cultured in semi-intensive ponds. The same diets offered in predetermined amounts to shrimp in an outdoor, recirculating green water system resulted in no significant differences (p > 0.05) between treatment means for final weight or weekly growth rate. However, there was a significant difference (p = 0.021) in survival between the AP treatment (85.83%) and the FH treatment (95.83%), which led to the final biomass (p = 0.004) and FCR (p < 0.0001) of the AP treatment being significantly different from all other treatments. The reduced response observed in the AP treatment suggests that the addition of attractants may improve the performance of plant-based diets in RAS.