Fish oil

Description: 

Fish oil is an excellent source of energy, Vitamin A , D and omega-3 fatty acids. Vitamin A and D are concentrated in the liver of fish, therefore the concentration of Vitamin A and D is higher in oils extracted from livers, such as, cod liver oil, tuna liver oil, etc. Vitamin A and D can normally be provide more economically using synthetic sources. Feeding of fish oil can increase the amount of unsaturated fat present in the tissues, especially of monogastric animals, which can cause the back fat to become soft and off-flavors to develop. The present of unsaturated fats in the edible portions becomes a more significant problem when those portions are being processed, such as when pork hams are being smoked and cured. The lipids associated with fish oil are highly unsaturated and can be oxidized easily, so they need to be properly stabilized and handled. Fish oils that have been oxidized can be toxic to animals and are highly unpalatable. 

Caution: 

Oxidation potential is high in fish oil, because of its content of highly unsaturated fatty acids. If the oil is not properly stabilized the formation of oxidative products can occur that can become toxic to an animal. These oxidative processes can be accelerated if the oil is exposed to light and air. Feeding of fish oil to animals, especially monogastric animals; can cause softening of fat deposits and off-flavors to develop in the edible tissues, so the care needs to be taken to assure that these problems doesn't affect acceptability of the final products.

Source:  

Extracted from fishery materials prior to making fish meal. 

Feeding Experiments: 

Fish oils can be used as dietary sources of energy, Vitamins (A & D), and omega-3 fatty acids. Tissue content of unsaturated fatty acids was found to increase as the level of fish oil in the diet increased in swine (2)(AGRIS 1998-041319)(Barowicz, 1997). Neonatal piglets are shown to have ample capacity to digest and absorb the lipid components contained in fish oil (20)(CAB N501016) (Chiang, 1989). Fat hardness decreased and iodine number increased of the body tissues of swine when fish oil was fed (3)(AGRIS 92-076718) (Irie, 1992). Carcass quality was negatively effected in swine carcasses when fish oil was fed (13)(CAB 981411640)(Urbanczyk, 1997). Off-flavors and increased unsaturated fatty acid content in the tissues of swine was observed when 1 to 3 % fish oil was fed (27)(CAB 961403100)(Overland, 1996). Feeding 3 to 6 % fish oil to 60 kg pigs was found to cause off-flavors in the edible tissues (6)(CAB 19991413785)(Lauridsen, 1999). The unsaturated fatty acid levels in milk from sows fed fish oil increased (23)(CAB 941401962) (Arbuckle, 1993). Feeding fish oil to pregnant and lactating swine was found to increase birth weight of piglets, increase piglet weight at 21 days and decrease piglet mortality (29)(CAB 951412651)(Walkiewicz, 1993). The progression was retarded and regression of arteriosclerosis was observed when swine was fed fish oil (16)(CAB N387000)(Sassen, 1989). Cholesterol levels associated with the Low Density Lipoprotein were increased when fish oil was fed to sows (33)(CAB 951402329)(Kirchgessner, 1994). Feeding of fish oil was found to increase insulin sensitivity in pigs (1)(AGRIS 1998-055987)(Behme, 1996). Feeding fish oil to layer was found to increase the unsaturated fatty acid levels in the eggs, reduce cholesterol and lipoprotein in yolk and caused only a slight change in taste (14)(CAB 981411835) (Rys, 1998), (15)(CAB,981411836)(Koreleski, 1998). The lipid composition in the tissues of chickens was altered when fish oil was fed (17)(CAB N328543)(Fritsche, 1991), (21)(CAB N243882) (Machin, 1990). Feeding broilers up to 0.83 % during the starter phase and 1.14 % during growing phase was found to have no affect on flavor of the meat (25) (CAB 981404896) (Saricicek, 1997). Unsaturated fatty acid incorporation occurred at a higher rate in the tissue as compared to the egg portion in layers when fish oil was fed (4) (AGRIS 94-082604)(Wang-Jianzhong, 1993). Egg weights were found to be decreased when layers receiving were fed fish oil (32)(CAB 951411004) (Whitehead, 1995). The arachidonic to linoleic acid ratio was lowered in the tissue of layers receiving fish oil (31)(CAB 951413820)(Takita, 1995). Plasma cholesterol was increased in chicks fed fish oil (30)(CAB 951413658)(Choi, 1995). 

Milk protein depression was observed when fish oil was fed to lactating dairy cattle (8)(CAB 19991413974)(Brzoska, 1999). The omega-3 fatty acid content of milk was increased when fish oil was fed to lactating dairy cattle (26)(CAB 971405622)(Walkiewicz, 1995). Dry matter intake in lactating dairy cattle was decreased when fish oil was fed and the polyunsaturated, especially omega-3 fatty acid levels were increased in the milk (10)(CAB 991402692)(Jones, 1998). Dairy cows fed fish oil tended to produce milk with lower milk fat percent and increased unsaturated fatty acid content (11)(CAB 991402694)(Jones, 1998). The eicosapentaenoic and docosahezaenoic acids in phospholipids were increased in calves when fish oil was fed (18)(CAB N289491)(Jenkins, 1990). 

Incorporating fish oil into carp diets increased gains, increased body fat levels and the level of unsaturated fat in the body fat reserves (22)(CAB N244366)(Viola, 1988). When fish oil was fed to tilapia no change in gain or body fat levels where observed, but the unsaturated fat level in the body fat did increase (22)(CAB N244366)(Viola, 1988). Omega-3 fatty acid levels in carp and tilapia were increased as when fish oil was fed (19)(CAB N275750) (Viola, 1990). 

The feeding of crude or deoxidized fish oil was evaluated in broilers and the crude fish oil was found to have a lethal effect (5)(AGRIS 83-932281)(Han, 1982). Oxidized fish oil was found to be toxic to mink (9)(CAB 991405467) (Borsting, 1998). Feeding fish oil to mink impaired reproductive performance (9)(CAB 991405467) (Borsting, 1998). 

Feeding fish oil was not found to affect rumen fiber digestion or rumen digestion when fed to dairy cattle (28)(CAB N513642) (Doreau, 1992). Feeding fish oil to cattle was found to decrease rumen NH3 and acetate levels (7)(CAB 19991413793) (Keady, 1999). The protection of fish oil by chemical treatment has been shown to be a way of reducing their modification in the rumen and for increasing the omega-3 fatty acid content in the milk of lactating dairy cows (10)(CAB 991402692)(Jones, 1998).

Feeding and Handling Characteristics:  

Fish oils need to be stabilized with antioxidants to maintain their quality.

Nutrient Characteristics: