Storage Stability of Omega3enhanced Rainbow Trout Oncorhynchus mykiss: 1 Refrigerated Storage Temper

1
Storage Stability of Omega-3-enhanced Rainbow
Trout (Oncorhynchus mykiss) 1 Refrigerated
Storage Temperature
Y. C. Chen, J. Nguyen, K. Semmens, S. Beamer, and
J. Jaczynski West Virginia University, Animal
Veterinary Sciences


Regardless of packaging method, the highest
(P
basal diet group, followed by basal diet 15
flaxseed oil (FO) 1500ppm alpha-tocopheryl
acetate (a-TA), basal diet 15 FO, and basal
diet 1500ppm a-TA for 12-day storage. No
interaction (P0.05) for lipid oxidation and
alpha-tocopherol content between FO and a-TA was
observed. Although FO decreased (P
alpha-tocopherol content and increased TBARS
values, higher (P
was only determined in a-TA group for a 12-day
storage. Overall, regardless of FO and a-TA, a
vacuumed package kept the higher (P
alpha-tocopherol content and lowered (P
TBARS values. In the fatty acid profile (FAP),
interactions (P
observed. Regardless of packaging method, a-TA
addition decreased (P
saturated FA and Docosahexaenoic acid (DHA), as
well as increased (P0.05) proportions of
unsaturated FA, total ?-3 FA, a-linolenic acid,
and Eicosapentaenoic acid (EPA) in the fillets
lipid when FO was present in the fish diet.
Table 1. Moisture (), fat (), alpha-tocopherol
content, and TBARS of trout fillets as affected
by supplementing trout with FO and a-TA
FO flaxseed oil a-TA alpha-tocopheryl acetate
Table 2. P-values of FAP in trout fillets as
affected by supplementing trout with FO and a-TA
(p-value0.05)
American Heart Association indicated that
omega-3 fatty acids (?-3 FA) in fish or fish
products reduce the risk of cardiovascular
disease. Institute of Medicine and the Food and
Nutrition Board suggested intake levels for n-3
polyunsaturated fatty acids (PUFA) at 1.6 g for
men and 1.1 g for woman. Flaxseed oil contains
the highest concentration of a-linolenic acid
(ALA) compared to other lipid sources used in
fish feeds. An ?-3-enhanced rainbow trout
(Oncorhynchus mykiss) was raised successfully on
our research farm. However, it is known that
lipid oxidation is one the major problems in fish
products. Moreover, polyunsaturated fatty acids
are more easily oxidized than saturated fatty
acids. Fat-soluble antioxidants, such as vitamin
E, play an important role in preventing the
oxidation of polyunsaturated fatty acids.
Alpha-tocopheryl acetate (a-TA), a vitamin E
derivative, is usually used as an antioxidant to
reduce lipid oxidation in food. The a-TA is the
most effective lipid-soluble antioxidant. Animal
and human studies suggest that the amount of
vitamin E required to prevent lipid peroxidation
inside the body increases with the amount of
polyunsaturated fat consumed. Our hypothesis is
that supplementing fish diet containing high
concentration of FO with a-TA will reduce lipid
oxidation of ?-3-enhanced rainbow trout fillets
during storage at 2?C.

• FO flaxseed oil a-TAalpha-tocopheryl
  acetate.
  
• Experimental design 2x2 factorial arrangement of
  treatment in a randomized complete block design.
  
• Test parameters moisture, alpha-tocopherol
  total fat content, fatty acid profile, and lipid
  oxidation (TBARS).

• The highest (Pobserved in basal diet group, followed by basal
  diet 15 FO 1500ppm a-TA, basal diet 15
  FO, and basal diet 1500ppm a-TA groups for
  storage of 12 days.
• Regardless of supplementing basal diets with a-TA
  and packaging method, FO reduced (Pa-tocopherol contents but increased (P0.05)
  TBARS in fillets. That might be due to lipid
  oxidative retardation by consuming a-TA.
• Regardless of supplementing basal diets with FO
  and packaging method, a-TA increased (Pa-tocopherol contents in fillets.

FO flaxseed oil a-TA alpha-tocopheryl acetate
ALA alpha-linolenic acid EPA Eicosapentaenoic
acid DHA Docosahexaenoic acid
FO 0 15 a-TA 0 1500ppm
Fig 1 Fat () of trout fillets as affected by
supplementing trout FO and a-TA (20C for
12d-storage)
Table 3. FAP in trout fillets as affected by
supplementing trout with FO and a-TA
Our objectives were to evaluate the effects of
FO and a-TA supplementations on lipid oxidation,
FAP, and alpha-tocopherol content of trout
fillets during storage at 2 0C.

• Regardless of supplementing basal diets with FO
  or a-TA, vacuum packaged fillets showed higher
  (Ppackaged ones. A vacuum package hinders oxygen
  contact with fillets. Therefore, a-TA may be
  required at lower concentration to retard lipid
  oxidation.
• There are interactions (Pa-TA on FAP. Regardless of packaging method, when
  supplementing basal diet with 15 FO 1500ppm
  a-TA, the lowest (PFA and DHA, as well as the highest (P0.05)
  proportions of unsaturated FA, total ?-3 FA,
  a-linolenic acid, and EPA in the fillets lipid
  were obtained.
• The results demonstrated that the vacuum
  packaging reduced lipid oxidation. To maintain
  ?-3 FA during storage in trout fillets obtained
  from FO supplemented trout, the feed should be
  supplemented with a-TA.