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Changing the Dietary Omega-6 to Omega-3 Fatty Acid Ratio Impacts Nursery Pig Performance More Than Increasing Omega-3 Intake Alone
The objective of this experiment was to determine if either increasing the intake of omega (ω)-3 fatty acids or the amount relative to ω-6 fatty acids (ω-6:ω-3 ratio) would impact nursery pig performance. A total of 300 newly weaned pigs (26 ± 2 days of age), blocked by gender, were housed in groups of 5/pen. Pens were assigned to one of 5 diets (n = 12 pens/diet) consisting of a control (Con; 10:1 ω-6:ω-3 ratio, 3.5% total fat, tallow based), 3 diets with 3.5% fat (plant based) and ω-6:ω-3 ratios of 10:1, 5:1 and 1:1 (3.5/10, 3.5/5 and 3.5/1 respectively), and a plant based 10:1 ratio diet with 5% total fat (5/10). This design allowed us to examine the effects of increasing ω-3 intake at a constant ratio (10:1 ratio; 3.5% vs 5% fat) and the effect of reducing the ω-6 to ω-3 ratio at a constant amount (3.5% fat; 10:1, 5:1 and 1:1 ratios). Pigs were weighed weekly for 4 wks. On d 0 and d 29, 6 pigs and 6 pigs/diet respectively, were slaughtered, allowing the calculation of whole body N, fat and water deposition. ADFI was higher for pigs consuming the 3.5/1 diet during d 21 to 28 (1.13 vs 0.96 kg/d; P = 0.01) when compared to pigs fed all other diets. Increasing ω-3 amount (constant 10:1 ratio), did not affect ADFI or ADG (P > 0.10); but when the ω-6:ω-3 ratio decreased (constant total fat), ADFI was highest for pigs consuming the 3.5/1 diet relative to those consuming the 3.5/5 or 3.5/10 diets during d 21 to 28 post-weaning (1.13 vs 0.97 vs 0.93 kg/d; P = 0.02). Pigs consuming the 3.5/5 diet had increased protein (82.5 vs 71.1 vs 74.2 g/d; P = 0.07) and water (342.1 vs 301.0 vs 313.0 g/d; P = 0.06) deposition rates relative to those consuming the 3.5/10 or 3.5/1 diets. Lipid deposition was unaffected by treatment (P > 0.10). Increasing the amount of dietary ω-3 fatty acids while keeping the ω-6:ω-3 ratio constant did not affect ADG, ADFI or carcass composition; however, when total fat was held constant, a 5:1 ratio led to improved ADFI in older nursery pigs, as well as increased protein deposition without altering lipid deposition.
Keywords: Swine, Omega-3, Performance