Just like you and me,
most poultry experience heat stress during their lifetime, even if they don’t live in a warm climate, where poultry are often raised. With average temperatures rising due to climate change, more birds encounter heat stress than ever before.
With a thermo-neutral zone of 18 to 36° C (64 to 97° degrees F.), birds can maintain their normal body temperature of 41° C (106° F.) when ambient temperatures are in this range. But when the mercury surpasses poultry’s thermo-neutral zone, birds’ natural ability to cool themselves diminishes. Unlike humans, birds don’t sweat to cool themselves. Instead, they rely on panting, wing lifting and water evaporation, which all expend energy. Evaporation of just 1 gram of water burns 540 calories of body heat.
Heat stress reduces appetite
and ultimately feed intake, and then there’s also a significant impact on gut health. All these negative forces lead to reduced intestinal absorption surface area and compromised intestinal barrier integrity. Without a healthy gut, endotoxins and pathogens rear their ugly head, fostering immunosuppression. In this state, birds’ immune response weakens, and they become more susceptible to inflammatory diseases.
Bottom line: When heat stress strikes, production efficiency – growth rate for broilers and egg production and hatching rate for layers – falls and morbidity/mortality risk rises. What does that mean to poultry producers? It’s simple economics: production cost per unit e.g., meat and eggs increases and consequently profitability decreases.
Heat stress relief is simply the right thing to do, and many producers use tools, such as fans and evaporative cooling, to mitigate heat stress. While these tools help cool birds from the outside, there are tools that “cool” birds from the inside, creating a healthier gut and consequently a healthier animal:
These cool-from-the-inside tools are called phytogenic feed additives (PFAs). PFAs comprise a wide range of plants, like herbs and spices, and plant-derived products, like essential oils and oleoresins, coming from 100-plus different plant oils, extracts and tinctures.
Feeding PFAs allows poultry producers to feed a more concentrated diet. It’s a thoroughly researched, best management practice in times of heat stress. Birds typically eat less when it’s hot and humid because eating expends energy. With a more nutrient-dense diet via PFAs, birds consume the necessary nutrients and foster a healthy gut.
What’s so cool about PFAs?
These natural products harness the power of nature to enhance palatability, which results in greater feed intake and nutrient digestion. Plus, PFAs exert antioxidant effects, helping birds combat immunosuppression caused by high heat and humidity. For example, thyme oil, a PFA component, improves antioxidant activity and intestinal integrity, resulting in higher ileal digestibility of organic matter, crude protein and ether extract, key building blocks for supporting meat and egg production. Plus, thyme oil reduces malondialdehyde (MDA) content in the enterocytes. Increased MDA leads to breast meat catabolism i.e., breakdown of muscle protein.
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Take home messages:
- Heat stress not only reduces feed intake, it also impacts gut health
- Due to their antioxidant effects, phytogenics are able to help birds combat immunosuppression caused by high heat and humidity
- PFAs allow poultry producers to feed a more concentrated diet and simultaneously improving gut health
References available upon request