Validation of a Feeding Stimulant Bioassay Using Fish Hydrolysates for the Pacific White Shrimp,Litopenaeus vannamei

A protocol for testing feeding stimulants on Pacific white shrimp, Litopenaeus vannamei, is described. Thirty‐five rectangular tanks (55 L volume) served as the test system into which ten 5–6 g shrimp were stocked. Every tank contained two bowls, each of which contained either 25 feed pellets of a Reference Diet or Test Diet (consisting of the Reference Diet with one test ingredient added). After 1 h, the difference between the number of pellets consumed of the Test Diet and the Reference Diet was used as the Response. Each of the four Test Diets contained a different salmon hydrolysate made from by‐products of the Alaska fish processing industry (included at 50 g/kg). A fifth commercial shrimp diet was also tested. Each Test Diet was tested against the Reference Diet over a 4‐d period in seven replicate tanks. The data were subjected to a one‐way ANOVA and a confidence interval for each treatment response was calculated. The confidence interval was used to assess the test ingredient as a feeding stimulant. Treatment means were compared using Tukey's test (α = 5%). All the hydrolysates tested were found to act as feeding stimulants.