As the summer months arrive and temperatures rise, swine producers’ concerns
also increase. This happens because heat stress has a severe and direct impact on pig
health, welfare, and performance. This consequently causes huge economic losses in the
industry associated with decreased feed intake, body weight gain, and meat quality. With
that in mind, many studies have been conducted to better understand the impacts of heat
stress on pigs, including how it can affect their immune system (Cui et al., 2016). For
instance, it’s reported that exposure to high temperatures can cause disruptions of normal
redox reactions in the pig’s body and increases oxidative stress through decreased gut
blood flow and increased core temperature (Cottrell et al., 2015), and damages the
epithelial barrier of the pig’s intestines (Pearce et al., 2012).
This is why it is important that we find alternatives to improving the immune system
and performance of the pigs. This is where selenium (Se) comes into play. Se is an
essential trace mineral for humans and livestock animals, as it plays a vital role in thyroid
hormone metabolism and the immune system (Li et al., 2021). As Li et al. (2021) conclude
in their study, a deficiency of Se can induce pathological changes in pigs since it can
decrease selenoprotein expression, evoking oxidative stress and activating inflammation.
Se also plays a vital role in the antioxidant defense system, working as a defender against
free radicals responsible for damaging cell membranes (Zhan et al., 2007).
And the source of Se matters. Selisseo® (Adisseo) is a pure source of organic
selenium consisting of hydroxy-selenomethionine, which is more readily metabolized by
animals. Studies evaluating different sources of selenium showed that selenomethionine
– an organic source of selenium, like Selisseo® – has been more effective than sodium
selenite, an inorganic source, in depositing Se in tissues. For example, comparing
Selisseo® (Adisseo) and sodium selenite at the same dosage (0.3 mg/kg of Se), it was
found that Selisseo® deposits a significantly greater amount of selenium in weaner pigs’
tissues, such as liver (2.27 vs. 1.45 mg/kg) and muscle (1.26 vs. 0.47 mg/kg) (Seli-Report
12). The organic source of selenium also provides a better antioxidant capacity,
enhancing the cell membrane’s integrity, improving meat quality, and extending the shelf
life of pork meat (Zhan et al., 2007).
Under heat stress conditions, the primary function of Se becomes crucial to
maintaining normal animal development. A recent study highlights that the barrier
damage and inflammation in specific portions of the intestine caused by heat stress are
protected with increased Se supply (He et al., 2021). Another study pointed out that a
combination of Se and recombinant superoxide dismutase reduces inflammation induced
by heat stress (Le et al., 2019). Also, as reported by Liu et al. (2017), the supply of Se at
levels higher than the standard (0.20 mg Se per diet kg) in a short period helped to
regulate the temperature of growing pigs exposed to heat stress.
Pure organic Se seems to be very effective on other monogastric animals under
heat stress. Results show the effectiveness of Selisseo® on poultry immunity and
productivity, as Selisseo®: modulated redox parameters to help broilers cope better with
a challenging situation and improve overall performance (Seli-Report 39; Seli-Report 26),
positively impacted gut barrier and immune functions (Seli-Report 39), and increased
triiodothyronine (T3) (Seli-Report 26). Also, for broiler breeders, Selisseo® increased
humoral immunity by 5.4% (Seli-Report 16).
For heat-stressed broilers and hens, Selisseo® improved the feed conversation
ratio (Seli-Report 26; Seli-Report 37), showed the highest Selenium transference to eggs,
and was capable of sustaining egg production during this environmental challenge (SeliReport 37). Additionally, the selenium deposition on broiler meat was higher with
Selisseo® as compared to sodium selenite (Seli-Report 11). Se deposition in tissues is a
good indicator of the efficiency of Se absorption – which varies according to the mineral
level and source – and organic selenium has been shown to be the most efficient source
(Briens et al., 2014), such as the Se source that Selisseo® provides.
In conclusion, dealing with the effects of heat stress in pig production involves
multiple approaches, as there is no single solution. A way to potentially mitigate the
negative impact of heat stress is by improving pigs’ immune response and intestinal
health. Organic selenium supplementation, such as Selisseo®, is a powerful tool for
enhancing the immunity function of pigs suffering from heat stress, which can
consequently benefit pig performance, health, and meat quality.
Briens, M., Mercier, Y., Rouffineau, F., Mercerand, F., Geraert, P. A. (2014). 2-Hydroxy4-methyl seleno butanoic acid induces additional tissue selenium enrichment in broiler
chickens compared with other selenium sources. Poultry Science, 93(1):85-93.
Cottrell, J. J., Liu, F., Hung, A. T., DiGiacomo, K., Chauhan, S. S., Leury, B. J., ; Furness,
J. B., Celi, P., Dunshea, F. R. (2015). Nutritional strategies to alleviate heat stress in pigs.
Animal Production Science, 55, 1391–1402.
Cui, Y., Hao, Y., Li, J., Bao, W., Li, G., Gao, Y., & Gu, X. (2016). Chronic heat stress
induces immune response, oxidative stress response, and apoptosis of finishing pig liver:
a proteomic approach. International journal of molecular sciences, 17(5), 393. Doi:
He, Y., Liu, Y., Tang, J., Jia, G., Liu, G., Tian, G., Chen, X., Cai, J., Kang, B. Zhao, H.
(2021) Selenium exerts protective effects against heat stress-induced barrier disruption
and inflammation response in jejunum of growing pigs. Journal of the Science of Food
and Agriculture, 102:496–504. Doi: 10.1002/jsfa.11377
Le, H. H., Vidacs, E., Phillips, D. J., Zhao, W., Furness, J. B., Gabler, N. K., Renaudeau,
D., Wijffels, G., Dunshea, F. R., DiGiacomo, K., Roura, E., Leury, B. J., Cottrell, J. J.
(2019). Effect of selenium and superoxide dismutase supplementation on heat stressed
pigs. Journal of Animal Science, 97 (2), p. 179.
Li, S., Sun, W., Zhang, K., Zhu, J., Jia, X., Guo, X., … & Zhang, J. (2021). Selenium
deficiency induces spleen pathological changes in pigs by decreasing selenoprotein
expression, evoking oxidative stress, and activating inflammation and apoptosis. Journal
of animal science and biotechnology, 12(1), 1-13.
Liu, F., Celi, P., Cottrell, J. J., Chauhan, S. S., Leury, B. J., Dunshea, F. R. (2017). Effects
of a short-term supranutritional selenium supplementation on redox balance, physiology
and insulin-related metabolism in heat-stressed pigs. Journal of Animal Physiology and
Animal Nutrition, 102:1–10. Doi: 10.1111/jpn.12689
Pearce, S. C., Mani, V., Boddicker, R. L., Johnson, J., Weber, T. E., Ross, J. W.,
Baumgard, L. H., Gabler, N. K. (2012). Heat stress reduces barrier function and alters
intestinal metabolism in growing pigs. Journal of Animal Science, 90257–9. Doi:
Seli-Report 11. Broilers response to heat stress and selenium supplementation. Adisseo.
Seli-Report 12. Evaluation of the feed efficiency of Selisseo® in weaner pigs. Adisseo.
Seli-Report 16. Effect of vit E and selenium on broiler breeder performance when raised
in mild tropical conditions. Adisseo.
Seli-Report 26. Effect of Selisseo® on performance and antioxidant status of chronically
cyclic heat-stressed finish broilers. Adisseo.
Seli-Report 37. Selisseo® sustains egg production and improves egg selenium deposition
in aged laying hens under heat stress. Adisseo.
Seli-Report 39. Selisseo® helps to maintain better performance in broiler unders heat
stress and high stocking density: the mode of action. Adisseo.
Zhan, X., Wang, M., Zhao, R., Li, W., Xu, Z. (2007). Effects of different selenium source
on selenium distribution, loin quality, and antioxidant status in finishing pigs. Animal Feed
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