ISSUE FOCUS FEED & ADDITIVE MAGAZINE November 2024 35 it is important to make a differentiation between L-selenomethionine (organic selenium) and all other sources of selenium. L-selenomethionine can directly be used for the synthesis of selenoenzymes and, another part, allows for an incorporation of selenium into animal proteins (e.g. animal tissue, colostrum and milk) by following the same pathways as regular methionine. This ensures a safe deposit of selenium which can be used later on, ensuring a continuous selenium supply, and a more efficient selenium supply to suckling piglets. All other sources of selenium cannot be incorporated into proteins, and only follow the pathway of selenoenzyme synthesis. For high performing sows, selenium nutrition is essential to ensure a proper antioxidant status, and reduce the negative effects of stress on piglets during gestation. On top of that, after farrow, the transfer of selenium (when feeding L-selenomethionine) into colostrum and milk contributes to a higher selenium intake of the piglets. In turn, by having piglets with an optimal selenium status, they have a better antioxidant response which improves resilience in early life. The Norwegian University of Life Sciences has published two papers on this topic (Falk et al. 2019, Falk et al. 2020), comparing the effects of different dietary selenium sources on sows and piglets. In the first study, a total of 32 sows were divided over four treatments: 1. Basal diet + sodium selenite (0.40 mg/kg) 2. Basal diet + sodium selenite (0.60 mg/kg) 3. Basal diet + L-selenomethionine (0.26 mg/kg) 4. Basal diet + L-selenomethionine (0.43 mg/kg) The L-selenomethionine used in this study was Excential Selenium 4000 from Orffa Additives B.V. When evaluating the results, it was shown that the levels in colostrum and milk for total selenium (Figure 1), selenoP (SelP), selenoalbumin (SeAlb) and selenomethionine (SeMet) were significantly higher (P<0.05) for the L-selenomethionine supplemented sows. The higher levels of inorganic sodium selenite did not increase the selenium transfer into milk. The follow-up study (Falk et al. 2020) continued with the piglets born from the sows mentioned above. Selenium Levels in Colostrum and Milk a a ab a bc b c c 0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 Colostrum (farrowing) Milk (weaning) Selenium levels (mg/kg) Sodium selenite (0.40 ppm Se) Sodium selenite (0.60 ppm Se) L-selenomethionine (0.26 ppm Se) L-selenomethionine (0.43 ppm Se) P<0.05 P<0.001 Figure 1. Total selenium levels (μg/L) in colostrum (farrowing) and milk (weaning) of sows fed different sources of selenium (sodium selenite and L-selenomethionine) at different dosages.
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