2. Supplementing gestation diets with omega-3 Research Outcomes

3. Omega 3 PUFA for gilts and sows How Omega-3s affect reproduction Outcomes from lactating sows Outcomes in gilts Outcomes from studies on lameness and sow turnover Recommendations

4. Omega 3 fatty acids – why are they important? All animals require some intake of fats for cellular function Fats used for Energy Fat soluble vitamin source (Vit. A and E), sources of retinol, B-carotene and - tocopherol antioxidants Cell membrane component Synthesis of prostaglandins and a reproductive role Formation of compounds associated with inflammatory responses, immune function and general health

5. Omega-3 in gilts and sows Palmer (1970) reported increase in litter size in first and second litter size by feeding sows fishmeal Following studies using fish oil showed supporting evidence (Perez-Rigau et al, 1995; Webel et al, 2004; Spencer et al 2004) while others found no response (Rooke et al, 2001; Estienne et al 2006) in reproductive performance Embryos and endometrium develop with high levels of EPA and DHA by day 19 when gilts fed dietary omega 3 PUFAs (Brazle et al 2009) The pig oocyte and follicular fluid contains relatively high levels of long chain PUFAs compared to other mammals (Homa et al, 1986; Khandoker et al, 1997)

6. Mechanism Litter size improved by higher embryo survival Ovulation rate unaffected Increases follicle size and oocyte developmental competence (better quality oocyte for fertilization) May affect the prostaglandins that support maternal recognition and implantation (PGE - luteotrophic) and reduce those that try and stop pregnancy (PGF - luteolytic). Acts in an anti-inflammatory capacity to reduce symptoms of lameness

7. Evidence from commercial studies N=106 N=97 P < 0.05 +1.0 live born Methodology: Mixed parity 2-9 Fed during lactation (18d to weaning) Smits et al, (2011)

8. Evidence from commercial studies Methodology: Mixed parity 5-8 Fed during lactation (27 d) and through to mating Smits et al, (unpublished) n=51n=57 Embryo 13.6 v 15.5, P < 0.06 Ovulation rate, NS ES 61.5 v 70.0%, P < 0.06

9. Combining lactation and early gestation omega-3 supplementation Methodology: Commercial piggery, parity 1-7 sows, 850 sows Lactation 20 daysControlsOmega 3 Pre-mating 5 days ControlsOmega 3 Mating day 0 Controls Omega 3 ControlsOmega 3 Gestation day 25All sows return to unsupplemented feed for the remainder of gestation

10. Mixed parity lactation vs early gestation Total born omega-3 effect P = 0.041 Live born omega-3 effect P = 0.100 Smits et al. 2011 n=173

11. Treatment x parity Smits et al. 2011 Improvements in older parities

12. PUFA plasma 12d gestation

13. Farrowing rate Treatment effect NS

14. Omega-3 in gilts Studies evaluated response to feeding supplemented gilt developer diets Feeding for 3 or 6 weeks before mating on litter size and farrowing rate Second study fed supplemented diets before mating and early (4 weeks) pregnancy Dose response 0, 3 and 10 g fish oil/kg

15. Gilt studies Treatment response NS Smits et al. 2012

16. Gilt studies Treatment response P <0.100 0 vs 3 g/kg P <0.05 Smits et al. 2012

17. Summary of omega-3 for improved fertility Sows Feeding supplemented diets during lactation and up to mating Increased litter size in older parities, no effect on farrowing rate Feeding supplemented diets during early pregnancy Increased litter size in older parities, no effect on farrowing rate Feeding both in lactation and early pregnancy Increased litter size overall (+0.5 BA), no effect on farrowing rate Replacing tallow with 3 g/kg (0.3%) fish oil increased EPA and DHA by 6- 7-fold Reducing n-6:n-3 ratio from 12.5 to 7.5 improved litter size and ES

18. Summary of omega-3 for improved fertility GILTS Feeding supplemented diets during puberty up to mating no significant benefit on litter size or farrowing rate Feeding supplemented diets during puberty and early pregnancy increase in embryo survival Feeding 3 g/kg v 10 g/kg fish oil during puberty and early pregnancy Maximal response at 3 g/kg No treatment effect on farrowing rate Small increase age at mating 217 d (Omega-3) v 213 d Control Smits et al. 2012

19. Supplementing gestation diets with omega-3 to reduce lameness Experimental design Gilt gestation Control diet 0 g/kg fish oil Omega-3 diet 6 g/kg fish oil 15 g fish oil/d Gilt lactation Control diet 0 g/kg fish oil Omega-3 diet 3 g/kg fish oil 18 g fish oil/d Parity 1 gestation Post-weaning Parity 1 lactation 2,000 mated gilts Day 2 Control diet 0 g/kg fish oil Omega-3 diet 6 g/kg fish oil 15 g fish oil/d Assessment of sow retention

20. Results - Reproductive TreatmentGilt farrow rate (%) Gilt live born Parity 1 farrow rate (%) Parity 1 subs live born Retention over two parities (% of mated gilts) Control90.810.884.012.172.6 Fish oil - 3g/kg91.610.884.412.275.8 SignificanceNS P=0.137

21. Results – Sow removal TreatmentRe-bred after parity 1 weaning (%) Mortality (%) Locomotion culls (%) All Physical removal (%) Control91.31.25.26.2 Fish oil - 3g/kg93.10.42.83.3 SignificanceNSP=0.09P =0.011P = 0.004

22. Omega-3 and sow retention Omega-3 supplements reduced sow wastage due to lower destructions and culling for lameness No effect on parity 1 (gilt) litter size when fed from d 2 post-mating No increase in parity 2 litter size, though high baseline due to parity 1 skip-a-heat)

23. Take-Home recommendations Supplementing diets with low levels of fish oil can increase litter size Evidence of improved physical fitness with prolonged supplementation Aim for dietary n-6:n-3 ratio of < 9 in lactation and (early) gestation diets Recommended intake of DHA (22:6) +EPA (20:5) of 2.9 g/day Sourcing quality fish oil or other sources of long-chain omega-3 important, as is suitable antioxidants and vit E in feed preparation

24. Thank you to the Pork CRC and Rivalea for funding and support during the project and my PhD