346
The perinatal transfer of vitamins and trace elements from sows to piglets
Nursing piglets are entirely dependent for their micronutrient provision on the transfer (in utero, colostrum and milk) from the dam and this lasts for approximately half the life cycle (conception to slaughter) of a pig. As an adequate maternal transfer of these micronutrients is critical, especially for high prolific sows, a simple approach was set up to assess the maternal perinatal transfer of vitamins and trace elements. Prenatal transfer was estimated as limited, passive, or active using a ratio (RU) between pre-farrowing serum concentrations of a given micronutrient in dams and corresponding pre-colostral values in piglets. Efficiency of the postnatal transfer was estimated, as for RU, from another ratio (RC) between serum concentrations of pre- and post-colostral micronutrients in piglets. Data from literature (11 studies) were used for vitamins A, D, E, C, B12, and folates whereas the others were generated from a trial where blood sera from 20 sows and their litter was collected during the perinatal period. T-tests were used to determine if RU or RC values differ from 1. Prenatal transfer was active and in favour of piglets (RU < 1, P < 0.01) for Zn and vitamins B6 and biotin (sow trial) as well as for vitamins C and B12 (literature data). This transfer was limited (RU > 1, P < 0.01) for vitamin B2, Fe, Cu, and Se (sow trial) and for vitamins A, E, D, and folates (literature data) whereas it was passive for vitamin B3 (RU = 1, P > 0.37). After birth, the early postnatal transfer through colostrum was active for most micronutrients but vitamins B6 and biotin (RC < 1, P < 0.01). Globally, the perinatal transfer (combination of RU and RC) was favourable to the neonatal piglets for most micronutrients except for vitamins A and D as well as iron, copper and selenium. For these vitamins and trace elements, it appears that the placenta acts as a barrier for prenatal transfer which is not thereafter compensated by the colostrum provision to neonatal piglets. Then, the post-colostral concentrations of these micronutrients in piglets remain below the levels of their dam before parturition. Milk being a poor source of micronutrients, piglets are at risk to suffer, shortly after birth and thereafter during lactation, from nutritional deficits other than Fe, well known for decades. New targeted neonatal strategies of micronutrient supplementation are possibly required nowadays for suckling piglets.
Keywords: micronutrients, sows, piglets