Heat stress: underlying mechanism and mitigation by yeast paraprobiotics

Dear all, stress generally and heat stress, for instance, has a lot of aspects. Regulation by hormones is only one of these aspects. The same important is hyperosmotic stress, dehydration of the cells. When it is not enough water inside the cell, hormones and immunostimulators will be not effective. In my opinion, it is a reason to combine yeast glucans of mannans with the cell osmolytes like betaine.

Excellent information from all the contributors. Dr. Fiodor has mentioned a very important point in heat stress management. Indeed, both the poultry house management (lowering house temperature, managing feeding time, air movement, etc) as well as nutritional adjustment (nutrient density and source of nutrients, inclusion of electrolytes and Vitamin C, etc) plays a vital role in lowering the impact of heat stress. A natural response to heat stress by poultry is to reduce the feed consumption, which ultimately affects performance. The source of methionine can also make a difference during heat stress. HMTBa as a source of methionine has been shown to be more effective than DLM in preventing the characteristic depression in bird’s performance during heat stress. Since HMTBa is absorbed by diffusion, and there is no energy requirement or heat production associated with diffusion, birds are able to better absorb HMTBa during heat stress with a minimal amount of physiological stress. This aspect is critical as the absorptive surface area of the small intestine is reduced by high temperatures and this may play a role in performance during and following heat stress.

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Mannan and B-glucans, also proteins are part of Yeast wall that you may not spare. This mix of product are the key part of yeast attach to TLR2-Dectin1 receptor to stimulate IgA production at peyer patches. So Yeast walls are yeast Wall there is no Mannan free product or b-glucan free products that lead to IgA production.
It is clear in your trials that the use of yeast wall help the bird to cope with heat stress by the effect of this high IgA concentrations in the intestine (as you mention in your trial and some other done). Gut integrity it is the main target to achieve in heat stress.

Heat stress continues to be a challenge, and any contribution to knowledge is welcomed. However, I would correct some of the points raised recently. Use of methionine sources will inevitably reduce heat stress, as correct formulation to SID amino acids will reduce crude protein content and thus energy expended in excreting excess nitrogen.
The choice of methionine source needs to account for this. As HMTBa, in reality, has an average BE of only 65% compared to DL Methionine, M+C deficiency is a possibility if higher BE values are used. Furthermore, the assertion that HMTBa is “more effective than DLM in preventing the characteristic depression in bird’s performance during heat stress” is not correct. Neither is the assertion that “HMTBa is absorbed by diffusion”. One should consider Maenz and Engele-Schaan (J. Nutr. 126, 1438-1444 1996) and Mitchell and Lemme (International Journal of Poultry Science 7 (3): 223-233 2008) as but two examples of the large body of work confirming that all methionine sources are transported by active-transport processes; and that response of birds to heat stress is not affected by methionine source.
Effective formulation, using accurate and precise digestible nutrient values, is undoubtedly a useful tool in reducing the effects of heat stress. Use of lipids as energy sources rather than carbohydrates; and use of salts such as potassium carbonate are more likely to provide relief.

All this aside as a farmer and with some nutritional knowledge in tropical areas in Uganda... I have observed better results in tropical conditions for Layer, especially with HMTba usage.

The claim and not sure but the observation is better tropical performance in Layers on HMTba

Heat stress is really a headache for farms, the integrated solutions can work well only, so the capsicum can contribute some works along with other solutions according to Pancosma's numerous research for many years, you will see the result if you can try with extract.

Farmers should study the direct effect of betaine, in reducing stress under heat stress condition, there are few types of betaine, it seems that the natural source is more efficient.

It must be kept in mind that YCW solutions like Safmannan, will have a much broader and more efficacious effect. Safmannan is able to bind pathogenic bacteria and will thus control the growth of opportunistic bacteria. Additionally, it will assist in the preservation of the tight junction integrity and in that way control bacterial translocation and gut inflammation. The control of gut inflammation is key in the mode of action to control the effects of heat stress.

Thank you Fiodor. Colleagues.

Thank you for this information.

When we talk about Yeast Cell Wall (YCW) and its benefits to mitigate heat stress, It's important to consider a YCW source that originates most as possible indigestible fibers (MOS and B-Glucans), as what we look for it's a YCW that is able to reach the intestine without being digested on the way through. Otherwise, we will have those sugars digested in the rumen and no effect as expected. We can find in the market such indigestible options and the product ImmunoWall its one of that most indigestible YCW available (with min. 30% B-Glucans and 17% MOS). We have some data to share in case of interest. Best regards.

Thanks, this is a great paper and that is the reality on the ground. In Uganda is very hard to keep birds in layer for a long time because of extremes temperatures.