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Prolificacy depends on the number of ovulations and/or the embryo losses during implantation and early post-implantation stages of pregnancy. Functional AA (either essential or non-essential) play a prominent role such as protein synthesis, polyamines, and NO, in the development of the placenta, conceptus, and associated structures. Previous studies in gilts, and under experimental conditions, suggest that AA supplementation may be a promising strategy for diminishing incidence of embryo losses. Although, practice conditions may produce different results. The present study assessed a short-term supplementation with L-proline during implantational stages of embryos, on litter size and birth-weight of piglets in different parity sows under commercial conditions. A total of 115 Landrace × Yorkshire crossbreed inseminated sows were used. Sows were distributed according to age, number of previous deliveries and body-weight to a supplemented group (top-dressing 14 g/day of L-proline) or a control.
There was no evidence of significant differences in multiparous sows with or above three parities. Nevertheless, additional L-proline enhanced the reproductive efficiency of high-prolific first-parity sows and all second-parity sows. The supplemented females had increased piglet birth weight, and only numerically, had greater number of piglets born alive (around two; not significant). Higher birth-weight was associated to differences in piglet weight distribution within the litter. Supplemented sows had 3.5 more piglets ≥1.3 kg BW (10.7 vs 7.3) and tended to have more piglets ≥1.3 kg BW (69.1 vs 54.4%) with less piglets ≤1 kg BW (6.9 vs 14.9%).
These results suggest that effects of supplementing L-proline on litter size and birth-weight were modulated by the maternal characteristics. More precisely, by parity and prolificacy. Because positive effects were observed on second parity sows and highly-prolific primiparous gilts, it could be that supplementation was cost-efficient only for females with compromised energy balance.
Gonzalez-Añover, P., and A. Gonzalez-Bulnes. 2017. Maternal age modulates the effects of early-pregnancy L-proline supplementation on the birth-weight of piglets. Animal reproduction science 181: 63-68. https://doi.org/10.1016/j.anireprosci.2017.03.016