Background: The yellowtail kingfish (Seriola lalandi) is a marine fish commonly produced in Pacific regions. However, development of this species as an alternative to other marine species in aquacultures is on a rise globally. Empyreal 75 is a proven value-added option to replace other protein ingredients in the diet. Replacement of common protein sources in yellowtail diets with Empyreal 75 is beneficial to understand application of this technology.

Objective: Test the production performance of yellowtail kingfish using Empyreal 75 in place of fish meal.

Materials and Methods:

• Treatments consisted of two diets containing either fish meal or Empyreal 75, with the latter diet supplemented to balance the amino acid profile (Table 1).
• Each treatment group had 100 yellowtail kingfish, weighing approximately 324 g, divided into four replicates with 25 fish per replicate.
• Feed response was measured at the end of 12 weeks with yellowtail counted and weighed to determine: weight gain, survival and feed conversion ratio.

Table 1: Composition of basal diet and Empyreal 75 diets. Diets formulated to contain 36% protein and 8% lipid.

Results:

• Although the control diet, containing fish meal, had higher growth production, this was not significantly different from the Empyreal 75 diet (Table 2).
• Empyreal 75-fed yellowtail had a slightly better feed conversion ratio.
• As noted in the below figure, muscle coloration was not affected by feeding Empyreal 75 and the Empyreal-fed fish had a “wild caught” nature due to coloration on the tail.

Table 2: Production response in yellowtail kingfish to Empyreal 75 fed over 12 weeks

Control Diet:

Empyreal 75 Diet:

Conclusions:

• Based on this research, Empyreal 75 can replace fish meal in yellowtail kingfish diets. However, total replacement may not be optimal.
• Based on other research, up to 15% replacement may be optimal to achieve equivalent or improved growth.
• Reduction in other proteins that may not be sustainable, or contain anti-nutritional factors, can be beneficial to production.