Whole-body retention of α-linolenic acid and its apparent conversion to other n-3 PUFA in growing pigs are reduced with the duration of feeding α-linolenic acid.
In the present study, fifteen growing pigs were used to determine the whole-body oxidation, retention efficiency (RE) and apparent conversion (AC) of α-linolenic acid (18 : 3n-3) to n-3 highly unsaturated fatty acids (HUFA), including EPA (20 : 5n-3) and DHA (22 : 6n-3). The pigs were fed a diet containing 10% flaxseed for 30 d. Whole-body fatty acid composition was determined at initial (27.7 (SE 1.9) kg), intermediate (day 15; 39.2 (SE 1.4) kg) and final (45.7 (SE 2.2) kg) body weight. On day 12, four pigs were fed 10 mg/kg of uniformly labelled (13)C-18 : 3n-3 (single-bolus dose) to determine the oxidation of 18 : 3n-3. Expired CO2 samples were collected for 24 h thereafter. The whole-body content of n-3 PUFA increased linearly (P< 0.0001) with time; however, the content of 22 : 6n-3 exhibited a quadratic response (P< 0.01) with a peak occurring at 15 h. As a proportion of intake, the RE of 18 : 3n-3 tended to reduce with time (P = 0.098). The AC of ingested 18 : 3n-3 to the sum of n-3 HUFA was reduced with time (P< 0.05; 12.2 v. 7.53 % for days 0-15 and days 15-30, respectively). The AC of 18 : 3n-3 to 20 : 5n-3 or 22 : 6n-3 was lower than that to 20 : 3n-3, both for days 0-15 (P < 0.05; 1.14 or 1.07 v. 7.06 %) and for days 15-30 (P< 0.05; 1.51 or 0.33 v. 4.29 %). The direct oxidation of 18 : 3n-3 was 7.91 (SE 0.98) % and was similar to the calculated disappearance of 18 : 3n-3 between days 0 and 30 (8.81 (SE 5.24) %). The oxidation of 18 : 3n-3 was much lower than that reported in other species. The AC of 18 : 3n-3 to n-3 HUFA was reduced over time and that to 20 : 3n-3 in the present study was much higher than that reported in other species and should be explored further.
Department of Animal and Poultry Science, Centre for Nutrition Modelling, University of Guelph, Guelph, ON, Canada N1G 2W1.
Héctor R
HR
Martínez-Ramírez
Department of Animal and Poultry Science, Centre for Nutrition Modelling, University of Guelph, Guelph, ON, Canada N1G 2W1.
John P
JP
Cant
Department of Animal and Poultry Science, Centre for Nutrition Modelling, University of Guelph, Guelph, ON, Canada N1G 2W1.
Anna K
AK
Shoveller
Department of Animal and Poultry Science, Centre for Nutrition Modelling, University of Guelph, Guelph, ON, Canada N1G 2W1.
James L
JL
Atkinson
Department of Animal and Poultry Science, Centre for Nutrition Modelling, University of Guelph, Guelph, ON, Canada N1G 2W1.
Cornelis F M
CF
de Lange
D000818:Animals; D004032:Diet; D004041:Dietary Fats / Q000378:metabolism*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D019597:Flax; D008460:Meat / Q000032:analysis*; D010084:Oxidation-Reduction; D013552:Swine; D017962:alpha-Linolenic Acid / Q000378:metabolism*
D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D017962:alpha-Linolenic Acid