How Rosemary and Oregano Help Chickens Cope with Heat Stress

Jenn Hoskins
29th January, 2024

Image Source: Natural Science News, 2024

It might seem a bit offbeat to think that the secret to keeping chickens cool could lie in the sprigs of rosemary and oregano adorning our dinner plates. However, researchers at the National Research Centre in Egypt have recently turned their scientific curiosity to these culinary herbs, specifically their extracts, as potential chill pills for poultry. You see, heat stress is a bit of a party pooper for broiler chickens. It messes with their growth, causes physiological stress, and can even throw their metabolism out of whack. Enter the scientists with a seemingly flavorful solution: rosemary leaves extract (RLE) and oregano leaves extract (OLE). First off, let's set the scene. Imagine 150 male chicks, all one day old, cluelessly entering the world, only to be assigned to a unique dietary experiment. These fluffy participants were split into five groups, ensuring each had the same number of feathered friends, and in a twist of fate, each group was given a different diet. There was the control group dining on the plain baseline buffet, while the other groups indulged in the baseline diet with a herbal twist—some got a sprinkle of RLE, and others a dash of OLE, each with varying concentrations. These chicks weren't just lounging around; they were living in a controlled "hot room" with temperatures kept to a warm 32 degrees Celsius with moderate humidity, simulating the kind of heat stress that chickens often face in real-life farms, especially in warm climates. The researchers weren't just throwing herbs into the mix based on a chef's recommendation. It turns out, rosemary and oregano pack quite the antioxidant punch, with a knack for neutralizing free radicals, those pesky molecules that can wreak havoc in cells. Specifically, RLE boasted a component known as ferruginol and OLE was rich in thymol, both known for their antioxidant capabilities. But how did the chickens fare on this herb-enhanced diet? Well, the group munching on OLE at the moderate dose (50 mg/kg of feed to be precise) did quite exceptionally—they ended up heavier than their peers and transformed feed into body weight more efficiently. Is it possible that oregano has unlocked a more robust way for chickens to grow? Maybe. The plot thickened when looking at the bloodwork, which is where the chicken rubber hits the hot road. The RLE high-dose group, along with the OLE high-dose group, showed a significant drop in plasma total lipids and LDL-cholesterol, respectively. Essentially, their blood was in better shape, less fatty, and more heart-healthy, even under the demands of a warm environment. Moreover, the antioxidant capabilities of the herbs seemed to extend internally, as some chickens exhibited improved total antioxidant capacity. And for those concerned with endocrinology, the RLE enhanced levels of a key hormone, T3, that helps regulate metabolism and body temperature. Now, let's talk about stress at the molecular level. Heat shock proteins (HSPs) are like molecular chaperones getting stressed-out proteins back into shape. Under heat stress, the level of HSPs generally goes up, indicating that the cells are feeling the heat. But here's where it gets fascinating: the researchers found that the inclusion of RLE and OLE at certain doses actually lowered the mRNA expression levels of HSPs in liver cells. This could suggest that cells were less stressed and more comfortable, like guests relieved to find air conditioning during a summer scorcher. So, what's the takeaway from all of this? Well, it seems adding a moderate amount of oregano leaves extract to the diet of broiler chickens could be a bit of a game-changer. It's not just about growth; it's about how well birds can handle the stress of heat, and that's crucial for farmers seeking more humane and efficient production. In sum, chickens might just be happier and healthier pecking at a feed that's been thoughtfully seasoned with the essence of these time-honored herbs. Perhaps, in the not-so-distant future, aromatic plants could be as common in animal feeds as they are in our spice racks, redefining 'seasoned to taste' in a way that benefits poultry wellbeing and productivity. Now isn't that something to cluck about?

Herbs Nutrition

References

Main Study

1) Growth performance, blood biochemistry, and mRNA expression of hepatic heat shock proteins of heat-stressed broilers in response to rosemary and oregano extracts.

Published 26th January, 2024

https://doi.org/10.1016/j.jtherbio.2024.103791

References

Main Study

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