Krill as Bait Attractant
Both fish and crustaceans live in an immersed aquatic environment, where their chemioperceptive system receives permanent stimulation by solubles compounds. These substances are usually of low molecular weight, non-volatile and most of them contain nitrogen (aminoacids, nucleotides, etc.). These compounds stimulate the chemioperception of the animal (taste and smell), and its behavior (feeding behavior and intake). Krill is a natural bait for many species of fish and crustacean, for example, it is one of the main sources of food of wild salmon. Thanks to a low temperature production process, krill preserves all of its properties and it is being used in the aquaculture of salmon, shrimp, seabreanm and yellow tail. To provide higher palatability to the commercial feeds, to mask antibiotic taste, and to provide better acceptability to less palatant cost effective diets.
The feature of palatability in krill has been found to rest in the presence of certain aminoacids that stimutate the smell and taste, and in the existence of glycogenic aminoacids that are appetite stimulants. Furthermore, krill also features other substances of low molecular weight that are reported to have similar effects as palatants, such as TMAO (Trimethyl amine Oxide).
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 Proves that the feeding behavior of several species (sea bream, Japanese eels, black sea breams, and yellow tail) are stimulated when krill is added to the feed. Feeding stimulation in sea bream, Pagrua major, fed diets supplemented with Antarctic krill. Shimizu, et al. (1990) Aquacultue 87:43-53 Through the use of eletrophysiological tests it proves that krill extracts stimulate the smell response of sea bream. It was also found that the non protein of the krill contains smell and taste stimulants, and specific aminoacids were identified which probably were responsible for this effect. Food Preference of P. vannamei. Ogle and Beaugz (1991). Gulf Research Reports 8:291-294
It shows that P. vannamei has a strong preference for feed which includes krill. The study included the use of 16 ingredients usually incorporated in commercial feed for broodstock. Of all these ingredients, krill was only outperformed by artemia.