Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on growth performance and carcass quality of offspring.

Effects of a marine oil-based n-3 LCPUFA supplement (mLCPUFA) fed from weaning until the end of the next lactation to sows with a predicted low litter birth weight (LBW) phenotype on growth performance and carcass quality of litters born to these sows were studied, based on the hypothesis that LBW litters would benefit most from mLCPUFA supplementation. Sows were allocated to be fed either standard corn/soybean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. The growth performance from birth until slaughter of the litters with the lowest average birth weight in each treatment (n=24 per treatment) is reported in this paper. At weaning, each litter was split between two nursery pens with three to six pigs per pen. At the end of the 5-week nursery period, two barrows and two gilts from each litter that had individual birth weights closest to their litter average birth weight, were moved to experimental grow-finish pens (barn A), where they were housed as two pigs per pen, sorted by sex within litter. Remaining pigs in each litter were moved to another grow-finish barn (barn B) and kept in mixed-sex pens of up to 10 littermates. After 8 weeks, one of the two pigs in each pen in barn A was relocated to the pens holding their respective littermates in barn B. The remaining barrows and gilts were individually housed in the pens in barn A until slaughter. Maternal mLCPUFA supplementation increased docosahexaenoic acid (DHA) concentration in the brain, liver and Semitendinosus muscle of stillborn pigs (P<0.01), did not affect eicosapentaenoic acid and DHA concentrations in sow serum at the end of lactation, and did not affect average daily gain, average daily feed intake or feed utilization efficiency of the offspring. BW was higher (P<0.01) in the second half of the grow-finish phase in pigs from mLCPUFA sows compared with controls in barn A, where space and competition for feed was minimal, but not barn B. Carcass quality was not affected by treatment for pigs from barn A, but maternal mLCPUFA supplementation negatively affected carcass quality in pigs from barn B. Collectively, these results suggest that nutritional supplementation of sows can have lasting effects on litter development, but that feeding mLCPUFA to sows during gestation and lactation was not effective in improving growth rates or carcass quality of LBW litters.

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on birth litter quality and growth performance to weaning.

The effects of a marine oil-based n-3 long-chain polyunsaturated fatty acid (mLCPUFA) supplement fed to the sow from weaning, through the rebreeding period, during gestation and until end of lactation on litter characteristics from birth until weaning were studied in sows with known litter birth weight phenotypes. It was hypothesized that low birth weight (LBW) litters would benefit more from mLCPUFA supplementation than high birth weight litters. A total of 163 sows (mean parity=4.9 ± 0.9) were rebred after weaning. Sows were pair-matched by parity and litter average birth weight of the previous three litters. Within pairs, sows were allocated to be fed either standard corn/soyabean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. Each litter between 9 and 16 total pigs born was classified as LBW or medium/high average birth weight (MHBW) litter and there was a significant correlation (P<0.001) between litter average birth weight of the current and previous litters within sows (r=0.49). Sow serum was harvested at day 113 of gestation for determination of immunoglobulin G (IgG) concentrations. The number of pigs born total and alive were lower (P=0.01) in mLCPUFA than CON sows, whereas the number of stillborn and mummified pigs were similar between treatments. Number of stillborns (trend) and mummies (P<0.01) were higher in LBW than MHBW litters. Tissue weights and brain : tissue weight ratios were similar between treatments, but LBW litters had decreased tissue weights and increased brain : tissue weight ratios compared with MHBW litters. Placental weight was lower (P=0.01) in LBW than MHBW litters, but was not different between treatments. Average and total litter weight at day 1 was similar between treatments. mLCPUFA increased weaning weight (P=0.08) and average daily gain (P<0.05) in MHBW litters, but not in LBW litters. Pre-weaning mortality was similar between treatments, but was higher (P<0.01) in LBW than MHBW litters. IgG concentration in sow serum was similar between treatments and litter birth weight categories. In conclusion, litter birth weight phenotype was repeatable within sows and LBW litters showed the benchmarks of intra-uterine growth retardation (lower placental weight and brain sparing effects). As maternal mLCPUFA supplementation decreased litter size overall, only improved litter growth rate until weaning in MHBW litters, and did not affect pre-weaning mortality, maternal mLCPUFA supplementation was not an effective strategy in our study for mitigating negative effects of a LBW litter phenotype.

Responses to n-3 fatty acid (LCPUFA) supplementation of gestating gilts, and lactating and weaned sows.

Feeding n-3 long-chain polyunsaturated fatty acids (LCPUFA) to gilts or sows has shown different responses to litter growth, pre-weaning mortality and subsequent reproductive performance of the sow. Two hypotheses were tested: (1) that feeding a marine oil-based supplement rich in protected n-3 LCPUFAs to gilts in established gestation would improve the growth performance of their litters; and (2) that continued feeding of the supplement during lactation and after weaning would offset the negative effects of lactational catabolism induced, using an established experimental model involving feed restriction of lactating primiparous sows. A total of 117 primiparous sows were pair-matched at day 60 of gestation by weight, and when possible, litter of origin, and were allocated to be either control sows (CON) fed standard gestation and lactation diets, or treated sows (LCPUFA) fed the standard diets supplemented with 84 g/day of a n-3 LCPUFA rich supplement, from day 60 of first gestation, through a 21-day lactation, and until euthanasia at day 30 of their second gestation. All sows were feed restricted during the last 7 days of lactation to induce catabolism, providing a background challenge against which to determine beneficial effects of n-3 LCPUFA supplementation on subsequent reproduction. In the absence of an effect on litter size or birth weight, n-3 LCPUFA tended to improve piglet BW gain from birth until 34 days after weaning (P = 0.06), while increasing pre-weaning mortality (P = 0.05). It did not affect energy utilization by the sow during lactation, thus not improving the catabolic state of the sows. Supplementation from weaning until day 30 of second gestation did not have an effect on embryonic weight, ovulation rate or early embryonic survival, but did increase corpora lutea (CL) weight (P = 0.001). Eicosapentaenoic acid and docosahexaenoic acid (DHA) levels were increased in sow serum and CL (P < 0.001), whereas only DHA levels increased in embryos (P < 0.01). In conclusion, feeding n-3 LCPUFA to gilts tended to improve litter growth, but did not have an effect on overall subsequent reproductive performance.