The two main species of krill are harvested from the Antarctic Ocean (E. Superba) and the North East Pacific (Pacifica). Krill conglomerate in swarms to feed when the weather is warmer, allowing for high yield in a short window of time. Due to enzymes in krill they must be processed using quick freezing within hours of being removed from the cold water otherwise the krill begin to break down. This further allows the krill to retain their excellent nutrition and protein.
As a feed for salmon and trout, krill contain everything that fish naturally require for health and growth. Cultured species benefit greatly from the high fat, high protein and astaxanthin (a red carotenoid that gives salmon their pink flesh naturally). Krill as a feed provide vital lipids that can improve the color, size and taste of cultured fish species. It is evident that broodstock have healthier eggs and offspring from eating krill. Some research also proposes that fungal diseases may be reduced by using krill feedstock.
Perhaps the most important benefit of krill is their natural phospholipid (PL). PL may have a direct effect on the growth and feed intake.
One study indicates:
“An increasing tendency with increasing dietary PL level on feed efficiency was observed. In conclusion, the present study demonstrated that dietary PL supplementation could increase feed intake, and improve the growth of juvenile S. dumerili fed non-FM diets. Therefore, purified PL might be a good candidate to stimulate the growth of fish through enhancing the feed intake when they are fed diets containing alternative protein sources.”
The influence of dietary phospholipid level on the performances of juvenile amberjack, Seriola dumerili, fed non-fishmeal diets, O. UYAN , S. KOSHIO, M. ISHIKAWA, S. YOKOYAMA, S. UYAN, T. REN & L.H.H. HERNANDEZ
Krill meal contains on average 60% high biological value protein. It is typical to see:
Alanine, Arginine, Aspartic Acid, Isoleucine, Histadine, Glycine, Leucine, Lysine between 5% and 10% of protein.
Serine, Proline, Phenylalanine, Threonine, Tyrosine, Valine, Taurine, Methionine between 2% and 5% of protein.
Glutamic Acid can exceed 12%.
(see Tepual S.A & Raul Toro, independent report 1994)
Antarctic krill meal is an excellent source of organic minerals: Copper, Selenium, Zinc, Calcium, Phosphorous. Copper is known to have beneficial properties in fin and skin integrity in fish. As well, Selenium acts as an antioxidant.
Since krill is one of the main sources of food for wild salmon, it is a highly effective bait. Krill has low molecular weight soluable compounds such as proline and glycerine, glucosamine and trimethyl amine oxide. Since these compounds are found together, krill meal becomes an effective attractant and flavouring agent.
Supplemental effect of the whole body krill of the Euphausia superba in fish diet. Allahpichay and Shmizu. (1984) Bull. Jpn. Sci. Fish. 50:815-820
Feeding stimulation in sea bream, Pagrua major, fed diets supplemented with Antarctic krill. Shimizu, et al. (1990) Aquacultue 87:43-53
Separation of growth promoting factors from non-muscle krill meal of E. superba. Allahpichay and Shimizu. Bull. Japanese Soc. Sci. Fish. 51, 945-951.
Food Preference of P. vannamei. Ogle and Beaugz (1991). Gulf Research Reports 8:291-294