![Page 1: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/1.jpg)
Effects of Dietary Lipid Source and
Ultraviolet Radiation on Growth and Fatty
Acid Profile of Steelhead, Oncorhynchus
mykiss
Ronald Twibell*1, Ann Gannam1, James Barron1, Kieslana Wing1, Kyle Hanson1, Doug
Peterson1, Bethany Balmer2, Danielle Nelson2
1U.S. Fish and Wildlife Service
Abernathy Fish Technology Center
Longview, WA
2Department of Veterinary Microbiology and Pathology
Washington Animal Disease Diagnostic Laboratory
Pullman, WA
![Page 2: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/2.jpg)
Background
Fish oil is an important ingredient in fish feed.
![Page 3: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/3.jpg)
Background
![Page 4: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/4.jpg)
Background
Dietary fish oil and exposure to sunlight are key
factors in a disease known as steatitis
![Page 5: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/5.jpg)
Steatitis had been reported at different hatcheries.
![Page 6: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/6.jpg)
Steatitis is defined as inflammation of fatty tissue
![Page 7: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/7.jpg)
Steatitis
Caused by lipid oxidation
External signs include skin lesions and fin erosion
Occurs in animals that consume large amounts of
fish or fish oil such as crocodiles, cats, mink and
fishes
![Page 8: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/8.jpg)
Steatitis
Marine fish oil contains long chain-polyunsaturated fatty acids
(LC-PUFA) such as EPA and DHA
LC-PUFA are susceptible to peroxidation
Peroxidation in vivo results in biomembrane damage
Most lipids are devoid of LC-PUFA
![Page 9: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/9.jpg)
Fatty Acids in Lipids
_____________________________________________________________________
Fatty acid Canola Oil Fish Oil _________________________________________________________ % of Fatty Acids
EPA 0 14.6 DHA 0 9.3 _________________________________________________________
![Page 10: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/10.jpg)
Susceptibility of fatty acids to oxidation increases as
the number of double bonds increases
![Page 11: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/11.jpg)
Background
Antioxidants are added to feed to control rancidity.
![Page 12: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/12.jpg)
Background
![Page 13: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/13.jpg)
Study Objective
Examine the effects of dietary lipid source
and light source on growth, tissue
composition and steatitis in steelhead.
![Page 14: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/14.jpg)
Study Design
• Three dietary lipids: canola oil, control fish oil, oxidized fish oil
• Two light sources: fluorescent or ultraviolet (UV)
• Each treatment was assigned to three tanks of fish in a
completely randomized design
![Page 15: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/15.jpg)
Study Design
• Ultraviolet radiation supplied by two light fixtures with 26 watt
UVB bulbs.
![Page 16: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/16.jpg)
Study Design
• The UV lights were on a 12h:12h light:dark diurnal cycle in the
nine tanks.
• Mean UV intensity was 4.2 mW/cm2
• Mean UV intensity outdoors was 12.9 mW/cm2 (6/23/15,
Longview, WA)
![Page 17: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/17.jpg)
Experimental System
![Page 18: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/18.jpg)
Ultraviolet Lights
![Page 19: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/19.jpg)
Ultraviolet Lights
![Page 20: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/20.jpg)
Feed Composition
_____________________________________________________________________
Ingredient _____________________________________________________________________ Fish meal Wheat flour Corn gluten meal Feather meal Porcine blood meal Poultry meal Vitamin premix Mineral premix Choline chloride Guar gum Astaxanthin Ethoxyquin _____________________________________________________________________
![Page 21: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/21.jpg)
Diets
• Each lipid was added to a low lipid commercial diet to
produce three dietary treatments
![Page 22: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/22.jpg)
Study Design
• The oxidized fish oil was produced by aerating the control fish
oil at room temperature for 14 days using an aquarium air
pump.
![Page 23: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/23.jpg)
Lipid Oxidation
_____________________________________________________________________________________________________________________________
Dietary Lipid Source
_________________________________________
Canola Oil Control Fish Oil Oxidized Fish Oil _____________________________________________________________________
Peroxides (meq/kg) 5.8 5.3 21.0
______________________________________________________________________________
![Page 24: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/24.jpg)
Select Diet Fatty Acids
_____________________________________________________________________________________________________________________________
Dietary Lipid Source
_________________________________________
Canola Oil Control Fish Oil Oxidized Fish Oil _____________________________________________________________________
% of fatty acids
20:5n-3 (EPA) 2.8 12.0 12.2
22:6n-3 (DHA) 2.7 8.6 8.7
Total n-3 PUFAs 12.2 27.3 27.5
Total n-6 PUFAs 18.7 8.7 8.8
______________________________________________________________________________
![Page 25: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/25.jpg)
Dietary Lipid Concentration
_____________________________________________________________________________________________________________________________
Dietary Lipid Source
_________________________________________
Canola Oil Control Fish Oil Oxidized Fish Oil _____________________________________________________________________
Lipid (%) 18.0 18.2 18.4
______________________________________________________________________________
![Page 26: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/26.jpg)
Fish Husbandry
• 50 steelhead (1.6 g/fish) stocked into each of 18 tanks
• Rearing volume was 28.6 liters
• Water temperature was 12°C
• Fish were fed twice daily, seven days per week for 10 weeks
![Page 27: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/27.jpg)
Response Variables
• Growth responses
• Whole body proximate composition
• Whole body fatty acid composition
• Whole body histology for signs of steatitis
• Plasma enzyme activity
![Page 28: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/28.jpg)
Histology
• Two fish per tank were examined histologically
for steatitis.
• Histology assessed using a 0-5 grading system
(0=no steatitis and 5=severe steatitis).
• Pathologists had no knowledge of experimental
treatments.
![Page 29: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/29.jpg)
Statistical Analyses
• With the exception of histology results, data
were subjected to two-way ANOVA.
• Histology scores were subjected to regression
analysis for ordinal data.
• Accepted level of significance was 0.05.
![Page 30: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/30.jpg)
Results
• No external lesions observed on any fish
• Growth, body composition and histology were
affected by treatments
![Page 31: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/31.jpg)
Weight Gain
_____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
Weight Gain (%) 0.378 0.570 0.044
____________________________________________________
![Page 32: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/32.jpg)
300
350
400
450
500
Canola Oil Fish Oil OxidizedFish Oil
%
Dietary Lipid
Weight Gain
Fluorescent
Ultraviolet
![Page 33: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/33.jpg)
Histology
_____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
Steatitis Score 0.010 0.001 0.437
____________________________________________________
![Page 34: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/34.jpg)
a
b b x
y
y
0
1
2
3
Canola Fish Oil OxidizedFish Oil
Steatitis Score
Dietary Lipid
Steatitis Score
Fluorescent
Ultraviolet
![Page 35: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/35.jpg)
*
![Page 36: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/36.jpg)
Survival
_____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
Survival (%) 0.393 0.425 0.172
____________________________________________________
![Page 37: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/37.jpg)
Whole Body Lipid Level _____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
Lipid (%) 0.004 0.006 0.326
____________________________________________________
![Page 38: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/38.jpg)
y
x xy
b
a
ab
7
8
9
10
Canola Fish Oil OxidizedFish Oil
% Lipid
Dietary Lipid
Whole Body Lipid
Fluorescent
Ultraviolet
![Page 39: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/39.jpg)
Whole Body
n-6 Polyunsaturated Fatty Acids
(n-6 PUFAs)
_____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
n-6 PUFAs 0.001 0.036 0.283
____________________________________________________
![Page 40: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/40.jpg)
a
a a
6
11
16
Canola Fish Oil OxidizedFish Oil
% of fatty acids
Dietary Lipid Source
Whole Body n-6 PUFA
Fluorescent
Ultraviolet
x
y y
![Page 41: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/41.jpg)
Whole Body
n-3 Polyunsaturated Fatty Acids
(n-3 PUFAs)
_____________________________________________________________________
Probability Values
_______________________________
Lipid Light Lipid x Light
____________________________________________________
n-3 PUFAs 0.001 0.660 0.213
____________________________________________________
![Page 42: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/42.jpg)
b
a a
6
11
16
21
26
Canola Fish Oil OxidizedFish Oil
% of fatty acids
Dietary Lipid Source
Whole Body n-3 PUFA
Fluorescent
Ultraviolet
![Page 43: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/43.jpg)
Summary
• Steatitis observed in fish with no obvious external lesions.
• UV light and dietary fish oil significantly increased the
histological signs of steatitis.
• Low fish oil feed and raceway covers may reduce steatitis.
• Feeding steelhead old feed that may be rancid is not
recommended.
![Page 44: Effects of Dietary Lipid Source and Ultraviolet …...Effects of Dietary Lipid Source and Ultraviolet Radiation on Growth and Fatty Acid Profile of Steelhead, Oncorhynchus mykiss Ronald](https://reader033.vdocument.in/reader033/viewer/2022050310/5f728eb726de45618f1917ef/html5/thumbnails/44.jpg)
THANK YOU.