How can heat stress affect the quality of poultry meat?

How can heat stress affect the quality of poultry meat?

Genetic selection towards faster growing birds and higher breast yield has made the modern broilers more vulnerable to high temperatures. It is known that nowadays the negative effects of heat stress in commercial strains are observed at lower temperatures than several decades ago.

Besides the negative effects of heat stress on the oxidative status of the animalsegg qualityreproductive performancegut health and immune response, exposure to high temperatures also impairs the quality of poultry meat.

Three ways in which heat stress reduces the quality of poultry meat

1. Rapid drop in pH after slaughter

The pH changes in the muscle during the first 24 h after slaughter are important for the quality of the meat, because a very low pH or a relatively low pH combined with a high temperature of the carcass will lead to protein denaturation.

Whenever proteins are denatured, the muscles can not hold water and the meat appears pale, soft and exudative.

In normal conditions, after slaughter the metabolism in the muscles continues for a certain time. During this post-mortem period the glycogen is transformed into lactic acid through a process called glycolysis, which lowers the pH. 

In heat stressed birds, glycolysis is accelerated, leading to a very low pH in the muscle, while the temperature of the carcass is still high due to the hot environment.  

How can heat stress affect the quality of poultry meat?

2. Damage by free radicals

Poultry and poultry meat are particularly susceptible to oxidative reactions. As we explained in this article, high temperatures increase the oxidative stress of the birds,  causing:

  • Oxidation of the muscle proteins, that leads to poor water retention, bigger losses during cooking, less juiciness and decreased tenderness.
  • Oxidation of lipids, which worsens flavor, color, texture, nutritional value and acceptability in meat, while reduces its shelf life. Moreover, free radicals damage the liver and alter lipid metabolism, leading to more deposition of fat in the abdomen and less in the muscles.
How can heat stress affect the quality of poultry meat?

3. Increase of microbiological contamination

The risk of carcass contamination by foodborne pathogens, such as E. coli and Salmonella, increases during the episodes of heat stress. There are two main reasons:

  • Heat stressed birds are more prone to digestive infections, due to more challenges by pathogens and mycotoxins during hot weather, in addition to the immunosuppression associated with heat stress.
  • During heat stress the intestinal integrity is impaired, leading to intestinal permeability (leaky gut) and the spread of digestive pathogens to other organs.
How can heat stress affect the quality of poultry meat?

Essential oils prevent the damages caused by heat stress in poultry meat

The administration of essential oils, especially during the finisher stages, improves the quality of the carcass after slaughter:

  1. Raising the pH of the meat: it has been observed in several field trials that administering phytobiotics during all the life of the bird, and specially during the finisher stage, leads to a higher pH of the meat at slaughter. In a trial that we made recently (unpublished), we observed a higher pH in the breasts and legs of broilers that had been given PhytoShield©.
  2. Neutralizing free radicals: antioxidant essential oils relieve oxidative stress and prevent the damages in the proteins and fats, reducing water losses and the amount of malondialdehyde in meat (by-product of fat oxidation).
  3. Preventing microbiological contamination of the carcass: plant extracts and essential oils kill digestive pathogens, prevent leaky gut and are excellent immune boosters.
How can heat stress affect the quality of poultry meat?


PlusBreathe© contains essential oils with antiseptic, antioxidant, expectorant and natural mucolytic activity. It has a refreshing taste.

It is indicated to improve the functioning of the respiratory system and to mitigate heat stress in birds, ruminants, pigs and rabbits of all ages. It can also be nebulized in the farm environment. Contact us for more information about the use of the product.

SupraPlus© is intended to maintain and improve digestive health and to improve hydration in poultry, ruminants and swine of all ages. It is given through drinking water and is formulated with synergistic ingredients:

  • Bactericidal and fungicidal plant extracts, combined with organic acids for better effectiveness, that reduce the number of pathogenic microbes in the digestive system.
  • Plant extracts with prebiotic effect, that promote the growth of beneficial bacteria in the digestive system.
  • Electrolytes to maintain hydration
  • Sugars that are quickly absorbed and can be easily used as an energy source
  • Vitamin E

It is especially useful during the first week of life, to promote a healthy development of the digestive system and improve hydration; in case of digestive diseases, to improve gut health and restore the levels of electrolytes; in episodes of heat stress, to prevent digestive problems, restore the levels of electrolytes and fight with the body oxidation caused by free radicals.

GrowthPlus© (powder) and PlusProtect Digestive© (liquid) are our products based on plant extracts intended to maintain gut health during heat stress.

For more information on this topic and on our products, do not hesitate to contact us through

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