Production and Evaluation of Omega-3 Polyunsaturated Fatty Acid Enriched Pork

Value added pork products may be produced by enriching pork with health benefits providing omega-3 (n-3) polyunsaturated fatty acids (PUFA). It was hypothesized that feeding n-3 PUFA from ground flaxseed (FS; α-linolenic acid, ALA, is primary n-3 PUFA) or fish oil (FO; containing ALA and other long chain n-3 PUFA) only during the grower and early finisher phase represents an effective means to preferentially incorporate n-3 PUFA in targeted inter- and intra-muscular fat. The objectives of these experiments were to develop feeding strategies for cost-effective production of value-added pork products that contains predictable levels of n-3 PUFA without compromising carcass and meat quality, thereby providing health benefits to the consumer.

A serial slaughter study (Exp. 1; 45 purebred Yorkshire gilts; 2 Treatments) was conducted to determine the impact of feeding equal amounts of FS (5.2 kg/pig) at either early (25-50 kg BW) or late (85-110 kg BW) stages of growth on fatty acid (FA) content in trimmed loin and belly (expressed as mg/100 g of fresh tissue), as well as the whole body retention efficiency (RE) of ALA and n-3 PUFA. A combined growth performance and serial slaughter study (Exp. 2; 120 crossbred barrows and gilts) was used to assess the effect of timing of feeding n-3 PUFA from either FS or FO to pigs on the FA content and sensory evaluation of trimmed loins. Seven feeding regimes were used: FS or FO in corn based diets and either fed continuously (Treatments FSC and FOC, 25 to 120 kg BW), only during the growing phase (FSG and FOG, 25 to 65 kg BW), or only during the finishing phase (FSF and FOF, 90 to 120 kg BW). The control group (CON) did not receive any FS or FO. Results were subjected to Analysis of Variance using Proc Mixed of SAS 9.1v (SAS Inst., Cary, NS). Pigs within litters were used as a random effect. Differences among Treatments were assessed using the Tukey Honesty Significant Difference Test.

In Exp. 1 and based on measurement between 25 and 110 kg BW, total RE of ALA (69 vs. 86%; P>0.10) and n-3 PUFA (73.3 vs. 91.2%; P>0.10) did not differ between feeding regimes. Within trimmed loin and belly, the sum of the content of all n-3 PUFA (108 vs. 187, and 850 vs. 925) were similar (P>0.10) for FS early and FS late, respectively. No effect (P>0.10) on carcass and loin characteristics was observed. In Exp. 2, the content of ALA (274, 237, 187) in loin were similar across FS Treatments (P>0.10; FSG, FSL, FSC), and higher (P<0.01) than FO Treatments (40,39, 63 for FOG, FOF, FOC, respectively) and CON (30). In FO Treatments contents of long chain n-3 PUFA were higher (P<0.01; 122, 138, 129) than FS (102, 67, 77) Treatments and CON (32), respectively. Based on a trained taste panels, off-flavour ratings were higher for FOF than FSC (P<0.05), whereas ratings were similar for FSG, FSF, FOG, FOC, and CON (P>0.10). Feeding FS or FO had no effect (P>0.10) on carcass and meat characteristics among Treatments.

The n-3 PUFA content in loin and belly are independent of timing of feeding n-3 PUFA and can give flexibility as to when n-3 PUFA may be fed to produce n-3 PUFA enriched pork.
Implications. Feeding n-3 PUFA throughout the grower or finisher stages of growth resulted in predictable amounts of n-3 PUFA. Feeding fish oil in the pre-slaughter diets may reduce consumer acceptance of pork. Feeding modest amounts of n-3 PUFA leads to a significant enrichment of n-3 PUFA in pork and provide health benefits to consumers.

Keywords: Fish oil, flaxseed, efficiency of retention, pigs.