Approach time (sec) depending on treatments
27
20 18 16 14 12 10 8 6 4 2 0
Figure 1. Feed attractiveness depending on fishmeal content and treatment.
a set of trials and has demonstrated its ability to sustain growth and improve feed intake and feed conversion ratio (FCR) but the shrimp behavior was not followed. To better understand how a MFAA influences shrimp feeding activity, a trial was launched at the Kasetsart University in Thailand. A total of 432 vannamei juvenile shrimp were randomly placed into 36 aquariums filled with brackish water (15 ppt salinity). A range of three feeds with decreasing fishmeal levels (15%, 7.5% and 0%) were formulated. Each of the three diets were supplemented with 0.5% of MFAA. The product was mixed with other ingredients before
pelleting (Mix Group) or coated around the pellet after shaping (Ctd Group, see the detailed experimental plan in table 2). Shrimps were fed three times per day for eight weeks. Once every week shrimp behavior was thoroughly observed by trained technicians during the second meal of the day. In each aquarium, shrimps were gathered to one end of the aquarium behind a net and a feed tray was plunged at the other end of the aquarium. When the separation between animals and the feed was removed three parameters were recorded:
Shrimp eating in 15 minutes (number of individuals)
16 14 12
a c
abc
dc
bc
10
b
bc c d
8 6 4 2 0
FM 15%
FM 7.5%
FM 0%
Figure 2. Average number of shrimps eating pellets 15 minutes after the separation between feed and shrimps was removed. Data are the average of observations made in four aquariums per treatment for eight weeks.
Aquafeed: Advances in Processing & Formulation Vol 12 Issue 4 2020
