The difference was 0.5%. Besides the increase in consumer satisfaction, lower levels of purge also allow for more sellable meat, which is economically interesting. In total, the supplementation of Excential Selenium 4000 increased the profit with 83.13 RAND (€4.67 or $US5.33) per animal. The return on investment (ROI) of L-selenomethionine for this trial is 1:3.84.
Selenium and meat quality
Oxidation is a major cause of declining meat quality. During oxidation, free radicals can cause damage to proteins, lipids, and DNA. In order to improve meat quality, oxidation reactions should be reduced, both pre- and post-slaughter. Since selenium functions as an antioxidant, supplementing the diet of animals with selenium could reduce oxidation reactions and therefore improve meat quality. Over the past years, multiple research groups focused on the effects of different selenium sources on improving beef quality.
Grossi et al. (2021) investigated the effect of different selenium sources on the quality of beef. Results have shown that the organic selenium sources allowed for a decrease in shear force, which allows for an increase in beef tenderness.
Besides, drip loss and lipid oxidation were also shown to be reduced. During eight days of storage, the colour of the meat slightly changed as the lightness and yellowness were reduced. However, reduction in lightness was smaller in the groups of animals that received organic selenium sources in their diet, compared to the group receiving the inorganic source sodium selenite. Overall, the best results were found for organic selenium.
In another study, measuring the effects of inorganic and organic dietary selenium on meat quality of Charolaise beef cattle during the finisher phase, the results on improved meat quality were confirmed. Besides the significant improvement in selenium deposition caused by organic selenium compared to sodium selenite, shear force tended to reduce as well. Lightness and yellowness both significantly decreased upon storage with better results found in the organic selenium group. Colour was also scored visually, and this score was more optimal for the organic selenium group. Odour, overall appearance and surface wetness were also determined and were shown to be better for the group that received organic selenium. Overall, it can be concluded from this trial that tenderness, shelf life, colour and selenium deposition improved upon supplementation with organic selenium.
Difference in dietary sources of selenium
Selenium is an essential trace element with functions in animal health, reproduction and performance. During life, the trace element is involved in several processes. Selenium is incorporated in multiple selenoproteins such as glutathione peroxidase (GPx), thioredoxin reductase and iodothyronine deiodinases.
GPx and thioredoxin reductase function as antioxidants and protect the cellular metabolism from free radicals. Adding selenium to animal feed is an efficient way to enhance the selenium status of animals, allowing for improved animal health and production, but also to improve meat quality. In animal nutrition, both inorganic and organic sources of selenium can be used. However, the metabolic pathway in the animal is different between selenium sources (Fig. 3).