| dc.description.abstract | There is an increase in demand for fish and aquaculture around the world. When the demand
increase challenges arise such as sustainability, welfare and cost. There have been raised
concerns due to the feed the farmed fish is being exposed to with the replacement of aquatic
nutrients with land grown plant-based ingredients instead. With the addition of chemical
treatments of illnesses and excessive handling, stress levels of the farmed fish can affect
general fish health. By doing in vitro trialssome of these concerns can be reduced, by sparing
animals for testing, getting results fast and accurate related to the cellular structure tested and
since this is used more in the reason years, the cost has reduced significantly. This thesis
focusses on in vitro testing using two cell lines, PLHC-1 and RTgill-W1 and three different
bioassays to evaluate 7 different functional feed ingredients, vitamin C, β-glucans, arginine,
and four undisclosed ingredients factor F, factor Y, plant extract #1 and plant extract #2. The
aim of the thesis was to investigate the cellular responses when exposed to the functional feed
ingredients and determine an optimal concentration for these cell lines. This information can
be crucial for further feed formulations for farmed fish. The obtained results from all three
bioassay were compared to controls. Vitamin C increased the cell viability for both PLHC-1
and RTgill-W1. Reactive oxygen species (ROS) generation decreased when PLHC-1 and
RTgill-W1 were exposed to vitamin C. From these results the optimum concentration of
vitamin C was 1 μM/ml in PLHC-1 and 0.1 μM/ml in RTgill-W1. β-glucans gave a decrease
in cell viability in PLHC-1 and RTgill-W1 compared to the control. In RTgill-W1 signs of
cytotoxicity were detected at 1000 μg/ml of β-glucans. In the ROS assay oxidation decreased
for PLHC and increased for RTgill-W1 with significant increase at 1000 μg/ml of β-glucans.
Arginine had general stable cell viability for both PLHC-1 and RTgill-W1, but for PLHC-1
some decreases were detected in the 0.01 μg/ml concentration. In RTgill-W1 1000 μg/ml and
2000 μg/ml indicated cytotoxicity. Arginine decreased the oxidative production in PLHC-1
and did the same for RTgill-W1 in most of the concentrations except 0.1, 1000 and 2000
μg/ml which decreased ROS generation. The undisclosed ingredients (factor F, factor Y,
plant extract #1 and plant extract #2) didn’t have any signs of undesirable effects in cell
viability in both cell lines. Signs of cytotoxicity were detected for PLHC-1 at 1000 μg/ml of
plant extract #1 and for RTgill-W1 in 2000 μg/ml of plant extract #2. When they were
exposed to ROS assay the production of ROS generally decreased in PLHC-1, likewise for
RTgill-W1 except for RTgill-W1 were exposed to 2000 μg/ml of plant extract #2 it indicated
cytotoxicity compared to the control.
The overall data collected show compatibility of in vitro experiments with using cell lines
PLHC-1 and RTgill-W1 as a great addition for gaining knowledge and maybe reduce the time
consumed and animals tested in in vivo trials. This can further enhance the understanding of
the various procedures through which different ingredients are being integrated into farmed
fish diet. | |