The efficiency of OH-SeMet, to biofortify broiler breast muscle with selenium, was seen to be only ±80% compared to L-SeMet. The hydroxy form cannot be used directly by the animal as it must be converted to L-SeMet first before it can be used for protein production. Literature also states that the relative utilisation of hydroxy-methionine, compared to L-methionine, for chickens and pigs is only 80% (EFSA Journal 2012;10(3):2623). By augmenting the selenium concentration in broiler breast muscle, the animal has a reserve to combat different stressors during its lifetime. L-SeMet, in a chronic heat stress model, was able to improve BWG and FCR of broiler finishers (Michiels et al., 2016). After slaughter, L-SeMet also has a positive effect on meat quality. Broiler meat is especially vulnerable to (oxidative) stress as it is rich in long chain polyunsaturated fatty acids (PUFA). L-SeMet is not only able to reduce lipid peroxidation, but it also increases the alpha-tocopherol content (Skřivan et al., 2008). Other trials show a reduction in drip loss of almost 1%, after storing the meat for 48 hours, when diets are supplemented with L-SeMet compared to sodium selenite (Wang et al., 2011; Zhang et al., 2014). Vandaele et al. (2014) analysed the selenium content in milk samples of dairy cows after supplementation of 0,3mg Se/kg dry matter from sodium selenite, SY and a dust free preparation of L-SeMet (Figure 3). After seven weeks of treatment, the Se concentration in the milk was the highest in the L-SeMet group (75µg/kg).