Natural betaine: A nutritional aid during heat stress


Heat stress is considered a major climate change‐ related problem that is affecting the livestock sector even in temperate climates. The intensification of modern livestock production and genetic performance improvement also contribute to the increased incidence of heat stress. Natural betaine can be considered as one major nutritional aid to support animals in heat stress conditions.


BY ANA GAVRĂU, GLOBAL TECHNICAL PRODUCT MANAGER, AGRANA A


Production performance Reduced feed intake Reduced body weight Lower feed conversion ratio Decrease in egg production Increased egg abnormalities


Source: Fouad et al. 2016; G. Hemke, R.R. Santos, SFR, 2021


Physiological Increase in H/L ratio Increase in erythrocyte no. and decrease in haemoglobin Damage to intestinal mucosa


ll animals and birds have a zone of comfort, the so-called thermal neutral zone – the temperature range where the animals are most comfortable and perform best. Animals become heat stressed


when they have difficulty in achieving the balance between body heat loss and body heat production. The imbalance can be the combined result of environmental factors (for exam- ple, sunlight, temperature and other ambient conditions) and the natural defence mechanism of the animals (their rate of metabolism and the thermoregulatory mechanisms).


Adverse effects of long-term exposure Heat stress negatively affects the animal welfare and biological functions, with direct impact on the health status of


Figure 1 - Effects of heat stress on poultry physiological and biological functions.


Physical Parameters Increase in rectal temperature Respiration rate increases Heart beat rate raises


Hormonal/immunological changes Decrease in T3 Increase in HSP70 Effect on interleukin-2 Decrease in the expression of TLR 7 IgG production


the animals, their productivity and reproduction. Animals experiencing heat stress will reduce their feed intake. According to scientific data, feed intake can decrease 5 – 25% when temperatures rise above 25°C, depending on relative humidity. Due to reduced intake of nutrients and increased energy demand for thermoregulation, their production may drastically decrease. Additionally, long-term exposure to heat stress has adverse effects on the reproductive performances, which can lead to a high mortality rate and consequential economic losses. All animal species are impacted by heat stress, but poultry seems to be most sensitive and the effects of heat stress on poultry production are well documented (Figure 1). It is not easy to estimate how “comfortable” or “stressful” are the environmental conditions because the number of combinations of environmental factors is high. Poultry management at the farm level, such as biosecurity, cooling systems, ventilation, bedding materials, water quality, and stocking density are playing an important role. Besides technical solutions, nutritional strategies are gaining in interest as a useful solution to counteract heat stress. Farmers can add betaine to their different feeding strategies to mitigate the negative effects of heat stress.


Benefits of using natural betaine Commonly at the farm level the problems are multifactorial. Over the last years, the use of betaine in animal feed diets has moved from selective utilisation, to that of a core ingredient in key feed formulations for poultry, pigs and even ruminants. The increased use of betaine in animal diets has been driven by producer demands to counter performance challenges un- der heat stress conditions. The benefits are the result of be- taine’s role in two main physiological functions: its osmolyte property and acting as a methyl group donor. Both functions of betaine play a key role, particularly when animals are under challenging conditions, which include heat stress, temperature stress such as fluctuation between the day and night temperatures, dietary changes and pathogenic challenges (mainly coccidiosis which often causes wet litter). This in turn can lead to further severe complications like res- piratory disease or pododermatitis. The fact is, that the higher the challenge, the higher the demand on methyl groups. In such conditions, the mineral and water balance might be dis- turbed and the cell wall integrity potentially damaged. In the last 10 years, heat stress was not only observed in hot-climatic


24 ▶ HEAT STRESS | MAY 2021


PHOTO: AGRANA


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