Dietary supplementation with fish oil increases long-chain omega-3 polyunsaturated fatty acids in pubertal gilts

RJ Smits, BG Luxford and DJ Cadogan. 2009. Manipulating Pig Production XI, 46.

15-Apr-2010 (16 years 1 months 23 days ago)
Polyunsaturated fatty acids are essential nutrients for pigs as they lack the necessary enzymes for bio-synthesis from palmitic acid via elongation and desaturation reactions. Polyunsaturated fatty acids are incorporated into cell membranes and are precursors to prostaglandins and leukotrienes. These metabolites are involved in reproduction and inflammatory responses. Fish oil contains a high level of omega-3 long-chain polyunsaturated fatty acids including eicosapentaenoic acid (EPA; C20:5) and docosahexaenoic acid (DHA; C22:6). In this experiment we measured the polyunsaturated fatty acid profile in plasma of breeding gilts offered increasing levels of fish oil supplementation to the diet.

Thirty-six Large White x Landrace F1 generation gilts were housed in individual pens (4 m2) and offered diets from 20 weeks of age ad libitum. After three weeks on a basal diet (13.9 MJ DE; 150 g crude protein; 8.2 g lysine; 56 g total fat per kg), gilts of similar live weight and backfat P2 (100.8±1.7 kg;13.1±0.4 mm; mean±SE ) were assigned to one of six diets. The diets differed in inclusion levels of tallow and fish oil from 30 g tallow/kg and zero fish oil to 21 g tallow/kg and 9 g fish oil/kg. Dietary linoleic acid (LIN) and arachidonic (ARA) did not differ between the diets (30 g/100 g; 0.2 g/100 g fatty acids). Gilts were bled at 23 and 30 weeks of age and their plasma analyzed for fatty acid profile.

The fatty acid profile was similar before treatment diets were imposed with an n6:n3 ratio of 12.3±0.23 (mean±SE). There was a substantial increase in plasma EPA and DHA with fish oil supplementation of more than 1 g/kg, and a decrease in ARA level at supplementation levels more than 3 g/kg (P<0,05). There were no observed ill-effects of high rates of supplementation on sow health nor did live weight or P2 differ between treatments at 30 weeks of age (145.3±2.0 kg; 14.0±0.7 mm; P>0,05).

Supplementing the diet of pubertal gilts with 3 g/kg or higher changes the long-chain polyunsaturated fatty acid profile in plasma without adversely affecting growth or health.