PSII-9 Effects of Increasing Omega-3 Fatty Acids on Growth Performance, Mortality Rate, and Medication Usage in Prrs-Virus Challenged Nursery Pigs

Abstract

Abstract A total of 91,140 weaned pigs (DNA 600 × PIC 1050; initially 5.1 ± 0.05 kg) originating from PRRSV-positive sow farms, were used across 8 nursery sites to evaluate the effects of omega-3 fatty acids on growth performance, total removal and mortality rate, and medication usage of nursery pigs. Each of the 8 sites contained 5 barns with 2 rooms, and each room contained 40 pens with 27 to 28 pigs per pen. Rooms of pigs were blocked by nursery site and allocated within sow source to 1of 2 dietary treatments. Room was the experimental unit with 40 rooms per treatment with approximately 1,100 pigs per room. The first treatment was a standard nursery diet specific to the production system. The second treatment was the same standard nursery diet with the addition of 3% O3 Trial Feed. At placement, all pigs received 0.45 kg/pig of a common pre-starter. Pigs were then fed experimental diets across 3 phases with all diets fed in pelleted form. Oral fluids verified that 61 of the 80 rooms tested positive for PRRSV one-week post-placement in the nursery and 78 of the 80 rooms tested positive for PRRSV three weeks post-placement. Overall, there were no significant differences (P > 0.10) observed in growth performance between pigs fed diets containing 0 or 3% O3 Trial Feed (Table 1). Pigs fed control diets had reduced (P < 0.001) total removals and mortality percentage compared with pigs fed diets containing 3% O3 Trial Feed. When evaluating medication usage, there were no significant differences (P > 0.10) observed in the total number of injections given per 1,000 pig days. However, pigs fed diets containing 3% O3 Trial Feed had a reduced (P < 0.001) number of total injections per pig placed. In summary, the increase in omega-3 fatty acids in the diet, through the inclusion of 3% O3 Trial Feed, did not impact growth performance during the duration of this trial. There was an increase in total removals and mortality in pigs fed diets containing O3 Trial Feed. However, there was a reduction in total injections given per pig placed in pigs fed diets containing O3 Trial Feed. We hypothesize that because of the high prevalence of PRRSV at entry, O3 Trial Feed may not have had sufficient time to impact the immune system before the PRRSV challenge.