OMEGA-3 FATTY ACID LEVELS AND PERFORMANCE OF BROILER CHICKENS FED REDFISH MEAL OR REDFISH OIL

Abstract

Arbor Acre broiler chickens were fed six different diets to determine if the omega-3 fatty acid content of broiler chicken carcasses could be enhanced by feeding additional redfish meal (RFM) or redfish oil (RFO). The six diets were: control (no fish meal or fish oil); 7.5% RFM, 15.0% RFM, 30.0% RFM, 2.1% RFO and 4.2% RFO. Mortality at 28 d and 42 d was lower (P < 0.05) for birds fed RFO compared to those fed RFM. Feeding additional RFM or RFO had no (P > 0.05) effect on mortality, but resulted in lower body weights (P < 0.01) and feed consumption (P < 0.05) and poorer (P < 0.05) feed conversion. Additions of RFM or RFO to the diets resulted in a substantial dietary enrichment of omega-3 fatty acids (especially eicosapentaenoic acid, EPA or 20:5n-3; and docosahexaenoic acid, DHA or 22:6n-3). Analyses (wt/wt %) revealed that breast meat was lower (P < 0.001) in lipid and triglyceride but higher in cholesterol esters (P < 0.005), free cholesterol (P < 0.001) and phospholipid (P < 0.001) than thigh meat. Lipid, free cholesterol and phospholipid of edible meat lipid increased with duration of feeding (14 d, 28 d, 42 d) but triglyceride content decreased. Dietary treatment had no effect (P > 0.05) on carcass lipid content or composition. Breast meat lipid contained more (P < 0.001) of the omega-3 fatty acids (especially EPA and DHA), more n-3 docosapentaenoic acid (DPA or 22:5n-3) and more total n-3 polyunsaturated fatty acid (n-3 PUFA) than thigh meat lipids. EPA, DPA, DHA and total n-3 PUFA in edible meat lipids increased (P < 0.05) with duration of feeding. Feeding additional RFM and RFO resulted in an increased accumulation of the EPA (P < 0.001), DPA (P < 0.01), DHA (P < 0.01) and total n-3 PUFA (P < 0.001), primarily at the expense of the omega-6 fatty acids linoleic (18:2n-6) and arachidonic (20:4n-6). It can be calculated from the data presented that on average a normal meal (100 g) of chicken which has been fed 7.5% fish meal, would contribute 140 mg of omega-3 fatty acids (EPA + DPA + DHA). The same size meal of cod flesh would contribute about 135 mg of these fatty acids. Key words: Broiler chickens, breast, thigh, redfish meal, eicosapentaenoic acid, omega-3 fatty acids