Heat stress impairs nutrient absorption


One of the mechanisms that birds use to cope with high temperatures is the redistribution of blood flow: in the skin, vasodilation increases blood flow, to maximize radiant heat dissipation, while in the digestive system vasoconstriction reduces the blood flow. 

The reduction of blood flow in the gut causes a decrease in the supply of oxygen and nutrients, as well as an inadequate removal of metabolic wastes. leading to oxidative stress and compromising the health of the intestinal epithelium. Birds exposed to heat stress show an increase in glutathione peroxidase activity, which is an indicator of oxidative stress, and a decreased antioxidant capacity. 

On the other hand, during heat stress, animals reduce their feed intake. Feed restriction negatively affects the structure of the intestinal epithelium because feed contains certain compounds that stimulate tissue growth.

If birds are exposed to high temperatures for more than 24 h, the combination of oxidative stress and feed restriction leads to structural changes and injuries in the intestinal epithelium, especially in the duodenum and jejunum:

  • Epithelial cells in the villi are lost and the total area of covered by epithelial cells is reduced.
  • Villus height decreases and the width at its base increases, becoming flatter. 
  • Ratio of villus height to crypt depth decreases. Villus height to crypt depth ratio is one of the most important histomorphometric parameters of the small intestine, and a low value is correlated with a worsening in the digestion and absorption of nutrients.
  • In chronic heat stress, the total length of the intestine is reduced.

All these changes in the morphology of the intestinal epithelium lead to a decrease in the absorptive surface area and a reduction of the nutrient absorption capability.

Supplementation with natural antioxidants, that alleviate oxidative stress in the gut, is a good strategy to prevent or ameliorate structural changes and injuries in the intestinal epithelium.

On the other hand, certain essential oils are able to increase feed intake during heat stress by 10%, preventing the gut damages produced by fasting.

Products of choice

PhytoShield© is an oral emulsion that contains essential oils, electrolytes and vitamins intended to promote growth, reduce oxidative stress, and keep the animals hydrated.

PlusBreathe© contains essential oils with natural antiseptic, antioxidant, expectorant and 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...

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