Summer is just around the corner and it is time to prepare strategies to manage the impact of summer heat stress on poultry production efficiency.
Effect of heat stress on feed intake in poultry
Modern poultry is particularly sensitive to temperature-associated environmental challenges, due to their metabolic activity. Decreased feed intake in response to heat stress is the starting point for decreased body weight gain, feed efficiency, egg production and quality. Research has shown that a 12-day heat stress period in laying hens decreases feed intake by 29 g/bird, resulting in a 28.8% decrease in egg production. Others reported that for every 1◦C increase in temperature between 21◦C and 30◦C, appetite decreases by 1.5%, and for every 1◦C increase in temperature between 32◦C and 38◦C, the reduction is about 4.6% in laying hens. Studies in broilers have shown that birds reared in temperatures between (35 and 38 C) had significantly lower feed intakes and growth rates compared to birds reared in optimal temperatures.
Underlying mechanisms
There is general agreement that gut peptide hormones like Cholecystokinin (CCK) and Ghrelin have a role to play in appetite regulation in chicken. However, the role of these gut peptides in appetite regulation is not fully understood for poultry yet and there is some controversy around how their physiological roles may differ between birds and other vertebrates.
There is little information available on the underlying mechanisms for a reduction in feed intake in response to heat stress in poultry. One study investigating the effect of heat exposure on gene expression of various appetite regulating peptides in laying hens reported an upregulation of ghrelin mRNA in the hypothalamus as well as in the glandular stomach and jejunum. Suggesting that one of the pathways for the negative impact on feed intake of high ambient temperature in laying hens might be mediated by its effects on the hypothalamic and gastrointestinal ghrelin signals.
Supporting feed intake under summer heat stress
New nutritional concepts, such as gut agility activators, are designed to support the adaptive capacity and hence resilience of the bird by nutritional means. They help the bird to adapt to stressors by minimizing stress reactions including reduced feed intake. The gut agility activator Anco FIT Poultry has been shown to maintain higher feed intakes in broilers and layers compared to control animals in commercial conditions under summer heat stress. This was associated with higher weight gains and end weights.
