Introduction
Insect-based products are gaining in popularity as a good sustainable protein and oil alternative for animal feeds. Beyond fishmeal replacement, insect meal and oil present potential functional benefits to the farm-raised animals. In the present paper insect meal and oil, from Black Soldier Fly (Hermetia
illucens) larvae were tested at different inclusion rates in shrimp (Litopenaeus
vannamei ) diets.
Methods and Materials
The trial aimed at monitoring zootechnical performances including growth, survival and feed conversion ratio (FCR), and immune responses in laboratory conditions of PL12 individuals for a 45 days period. A seven day challenge test with Vibrio parahaemolyticus was also conducted on those juveniles where mortality was recorded and hepatopancreas histology compared between the control and test diet.
Five experimental groups, each with four replicates, were studied as follows: 2% Insect meal, 5% Insect meal, 10% Insect meal, 2% Insect meal + 2% Insect oil, and a control (without the inclusion of insect meal or insect oil).
Results
After 45 days of feeding, shrimp fed 2% Insect meal + 2% insect oil, and 10% Insect meal had a significantly higher average survival rate than other groups. At the same time, shrimp provided 2% Insect meal +2% Insect oil, 5% Insect meal, and 10% Insect meal, had a significantly higher average body weight and lower FCR than other groups. Regarding the immunological study, shrimp from all groups that provided insect meal had significantly higher imm une responses (the total hemocyte count, phagocytosis activity, phenoloxidase activity, superoxide dismutase activity, and bactericidal activity) than the control group. Shrimp from all groups that provided insect meal had fewer Vibrio spp in the hepatopancreas and intestine of shrimp than other groups.
Shrimp provided with 2% Insect meal +2% Insect oil had the best apparent digestibility of nutrients, including a percent dry matter digestibility, percent organic matter digestibility, percent protein digestibility, percent lipid digestibility, and percent nitrogen-free extract.
In the challenge test, all insect-based treatment showed a 26% better survival than the positive control (no insect ingredient). Furthermore, a noticeable reduction in the sloughing signs of the hepatopancreas was observed in the tested diets.
Conclusion
These results indicate health and performance benefits of insect meal and oil in shrimp diets in controlled conditions.