F performance was also demonstrated in poultry. In a first trial, laying hens were supplemented for 32 weeks (from 18 to 50 weeks of age) with different Se sources, going from SS, Selsaf® to a source of synthetic SeMet. As shown in figure 6 (A-C). The results clearly show that Selsaf® was able to reduce the mortality (A) of the layers while improving their laying intensity (B) and feed conversion ratio (FCR) per egg (C), compared to the other Se sources. In a second poultry trial done in broilers, additional evidence was gathered to evince that Selsaf® is more capable at improving broiler performance compared to other Se sources (inorganic and synthetic SeMet) as demonstrated by their final body weight at 42 days of age (Fig. 7) (Unpublished data). Consequently, it appears that Selsaf® is not only capable of ameliorating the antioxidant and immune function of animals but that it also comprises benefits for farmers by reducing morbidity/ mortality of the animals and by improving their performance.
Practical consequences for consumers
Finally, not only farmers seem to profit from the supplementation of their animals with Selsaf® but also consumers might experience some positive effect when eating end-products derived from animals supplemented with Selsaf®. As such, due to the presence of SeMet, Se is deposited in several animal derived products e.g. meat, milk, egg (Fig. 8) which are frequently consumed by humans. In this way, the consumption of animal products might lead to acquisition of natural Se in humans and
Figure 10; influence of Se from different sources on meat overall appearance
Figure 11; influence of Se sources on meat quality
consequently an improved oxidative status with better resistance to pathogenic infections. Additionally, it is well known that eggs are susceptible to lipid peroxidation due to the presence of polyunsaturated fatty acids (Mohiti-Asli et al., 2008). The oxidation level lipids can be demonstrated by the measurement of malondialdehyde (MDA), a secondary oxidation product formed during lipid oxidation. As such, the concentration of MDA can function as a parameter to assess the influence a certain Se source on lipid oxidation. As a matter of fact, foods appropriate for consumption should present lipid oxidation values below 3 mg MDA/kg of sample with an upper limit of 7-8 mg MDA/kg (Faitarone et al., 2016). Consequently, by using this parameter, it was recently demonstrated that Selsaf® is able to reduce the lipid oxidation in eggs during 35 days of storage (Fig.9), meaning that their shelf life would increase by supplementing hens with Selsaf®. In meat the oxidation of lipids and proteins is the most important parameter for the appearance of meat rancidity. On one hand, the oxidation of proteins in meat might decrease the activity of proteases and increases the myofibrillar protein cross linking finally resulting in tougher meat texture while lipid oxidation on the other hand might interfere with the integrity of the cell membrane leading to a lower water holding capacity and the formation of volatile oxidation products interfering with odor and flavor (Rossi et al., 2015). Recent data indicate that supplementation of Selsaf® to beef cattle might affect the color, odor, surface wetness and overall appearance of the meat during storage. Data clearly show that the color score was higher in the Selsaf® supplemented group from the 4th day and that the other score was higher on the last 2 days while surface wetness was higher starting from the 5th day of storage. Consequently, the overall appearance of the meat was increased from the 4th day of storage by the supplementation of Selsaf® to the animal (Rossi et al., 2015) (Fig. 10). This trial (Rossi et al 2015) and a recent trial performed in broilers (unpublished data) also showed that not only visual aspects of meat were affected by the supplementation of animals with Selsaf® but that also the water holding capacity (Fig. 11A) and the tenderness of the meat (Fig; 11B-C) were positively influenced to a higher degree compared to other Se sources even synthetic SeMet products. Water holding capacity and meat tenderness are respectively measured by means of drip loss and shear force i.e. the strength or force necessary to rupture a meat sample, indicating that the lower the force needed to rupture the meat the more tender the meat will be. These results are most a likely a consequence of the higher antioxidative status reached in meat when animals were supplemented with Selsaf® compared to the other Se sources as indicated by the measurements of GPx and total antioxidant capacity (TAOC) (Fig. 12A-B) (unpublished data). In fact, TAOC is the measurement of the combined non-enzymatic antioxidant capacity which thus provides information concerning the overall capability to counteract reactive oxygen species (ROS) and resist oxidative damages.
Conclusion
Figure 12; effect of Se source on antioxidant status of meat
68 | July 2016 - Milling and Grain
In conclusion, Selsaf® is a natural source of selenomethionine and selenocysteine offering a dual protection against both oxidative and pathogenic stress for the animal but also exhibiting benefits for farmers and consumers by sustaining animal health and enhancing zootechnical performance for farmers and raising consumers’ satisfaction while preserving food quality during shelf life. References available upon request