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Sweat Odor Compound Properties of Holstein Cows,
Ö. Anitaş1, S. Göncü1, N.Y. Özoğul2 , N. Koluman1, and S. Bozkurt1
Department of Animal Science, Faculty of Agriculture, University of Cukurova, Adana. Department of Hunting and Processing Technology Faculty of Fisheries, Çukurova University, Balcalı-Adana
Introduction
Sweating is one of the physiological (natural) functions to keep body temperature constant. Dowling (1958) reported that sweating in cattle is important for thermoregulation mechanism. Skin surface and its properties in cattle is one of the most studied subjects from different aspects. However, although regulation of sweating and body temperature is one of the main tasks, there are very few studies focusing on sweat glands or their biology.
Studies have shown that there are regional anatomical differences in sweat gland density (Findlay and Yang 1950). In addition, Berman (1971) in his research, suggests that the temperature of the skin is the main input that directs the rate of sweating. Sweating and inhalation are two of the main autonomic responses exhibited by animals under temperature stress. Sweating causes evaporative heat loss from the skin surface, while respiration is used to heat water vapor and to remove heat from the lungs in the form of vaporized moisture. Evaporative cooling at high temperatures in dairy cattle is the most important method of heat loss (Gebremedhin and Wu, 2001;2008). Cattle sweat is hypotonic, containing mostly potassium (K+ ), along with sodium (Na+ ) and chloride (Cl- ) (Johnson, 1970) In their study by Nascimento (2015), they stated that sweat glands are important in thermoregulation of cattle in hot environment and also help to dissipate heat. Studies on the histology of the gland are important to identify heat removal and perspiration capacity and secretory potential. Mochalski et al. (2015) stated that volatile organic compounds (VOCs) emitted by the human body can provide valuable information about a person's physiological state and thus create a chemical signature that can be seen to detect stress and disease states. For this study, they created a database of potential biological markers of human presence based on literature reports on human respiratory rate, skin emissions, and VOCs in blood and urine. They tried to determine the approximate proportions of these VOCs in the human body. Animals emit a range of molecules that are volatile and non-volatile, depending on their immune status, stress, nutrition, and genetic status. A large number of volatile compounds can be emitted from different parts of the body. SPME-GC / MS developed for the analysis of animal odor profiles allows identification of volatile organic compounds found in cow odor samples. By this method it is possible to determine the combination of the relative ratios of the common compounds and the presence of the different compounds. The secretion of sweat in temperature stress and disease states of animals may contain different substances as biological markers of particular disease or adverse events in the body. Volatile odor compounds (pheromones) emitted from feces, urine, saliva, milk, vaginal discharge and sweat of cows are composed of a combination of two or more chemicals that are spread at certain rates to be biologically active (Wyatt 2009 and 2010). Sweat is a dilute electrolyte solution excreted by the eccrine (sweat) glands in the skin of mammals. Although the main function of perspiration is to control body temperature by evaporative cooling, it has been proposed that certain components of sweating (eg androstadienone (4,16-androstadien-3-one)) can also be used as chemosignals that affect the hormonal balance and therefore behave as feromonal stimuli. The lack of a broad application of the term sweat in medicine and biology is explained by the difficulties sufficient for the analytical work of the sweating sample. Although the sweat composition is essentially water, previous studies have shown that various organic and inorganic compounds are also present. Volatile organic compounds (VOCs) emitted by an animal body can provide valuable information about the physiological state of the animal. Gas compounds [such as reduced sulfur compounds (RSC), organic acids, carbonyls and nitrogenous compounds (ammonia and trimethyl amine)] have been searched for the
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determination of volatile odor components (Wyatt, 2009). Since sweat glands are the most common in the neck region, sweat samples are taken from the neck region which is thought to be the most perspiration. GC-mass spectrometry (MS) was identified. The advancement of analytical methods such as GC, GC-MS and GC-MS-O provided the opportunity to identify VOCs for disease and disease-specific VOCs in research laboratories. Finally, it should be noted that odor information is useful in elucidating the cause of diseases. Some infectious or metabolic diseases will be possible by explaining the mechanisms underlying the production of specific odors. Microbial analysis of volatile organic compounds (VOCs) from biological samples and investigation of biosynthetic pathways that produce relevant VOCs from patients may help to better understand the pathophysiological mechanisms that cause a particular disease (Wyatt, 2010). The loss of evaporation depends on moisture and physiological factors, for example the activity and density of the sweat glands. In cattle, body cooling by cutaneous evaporation is the most effective way to dissipate heat, and so perspiration glands are the most important for adapting ruminants into the tropical environment. The hypothesis that volatile organic compounds (VOCs) emitted by the living body can provide valuable information about the physiological state of the organism and thus generate a chemical signature to detect stress and disease states has formed the starting point of this study. Because volatile organic compounds (VOCs) emitted by the body through sweat can provide valuable information about the physiological state of the organism and thus generate a chemical signature to identify stress and disease (Pandeyand Kim, 2010). In this study, it was aimed to determine sweat odor compound properties of Holstein cows.
Materials and methods
Animal material of this study 3-7 years old, the similar (physiologic stage, body weight, and milk production level) 6 Holstein cows were used. Sweat samples taken from the neck region of the animal where sweat glands are the mostly placed. The sample moved freely at the sampling site for 30 minutes before sampling. GasChromatography / MassSpectrometry (GC / MS) method used to detect sweat chemical odor compounds in siliconized glass bottles. Samples from each animal were analyzed in 3 replicates using GasChromatography / MassSpectrometry (GC/MS) method . Data description were made using the SPSS 2019 program.
Results
Odour is a volatile chemical compound that animals perceive via the sense of smell or olfaction. The type of odor molecule is called an aroma compound or an odorant. These compounds have been studied widely in plants, bacteria and insects, and to a much lesser extent in vertebrates. Chemical odor compounds detected in the sweat of animals were given Table 1.
Table 1. Chemical odor compounds detected in the sweat of Holstein cows
Compund name Rate (%) Minimum Maksimum
Butane,1-bromo-1,1,2,2,3,3,4,4,4-nonafluoro- 22,93±4,6 1,00 41,30 methyl 2-(3-phenylprop-2-enamido)acetate 5,34±1,66 ,00 16,50 1H-Indole 14,99±2,1 3,00 29,30 benzoicacidethyl ester 3,04±,45 ,00 4,80 1-Octanol, pentadecafluoro- 6,65±2,03 ,00 20,20 Nonadecan-1-ol trimethylsilylether 10,93±1,72 ,00 18,50 Perfluorotributylamine 47,18±6,69 7,00 89,10 Heptadecanoicacid 11,69±,97 7,30 18,00 1-Pyridineacetamide, 3-cyano-N- 9,38±2,83 ,00 28,20 Phosphine, 1,2-ethanediylbis 11,94±,51 9,40 15,20 1-Propanamine, 3-dibenzo[b,e] thiepin 10,74±,54 7,20 13,10
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Chemical odor compounds detected in the sweat of Holstein cows are Butane,1-bromo- 1,1,2,2,3,3,4,4,4-nonafluoro, methyl 2-(3-phenylprop-2-enamido)acetate, 1H-Indole, benzoicacidethyl ester, 1-Octanol, pentadecafluoro, Nonadecan-1-ol trimethylsilylether, Perfluorotributylamine, Heptadecanoicacid, 1-Pyridineacetamide, 3-cyano-N, Phosphine, 1,2-ethanediylbis and 1-Propanamine, 3-dibenzo[b,e] thiepin. Minimum maximum values is very differ between the samples. When Chemical odor compounds results (Table 1 ) is examined, it is seen that the chemical odor compounds of the animals significantly varies between animals. This are very işnetersting copounds which can be used for cattle specific information. Organic odorants fall into several categories, including esters, terpenes, amines, aromatics, aldehydes, alcohols, thiols, ketones, and lactones (Helmestine, 2019). The molecular weights of these compounds less than 300 Daltons, and are readily dispersed in the air due to their high vapor pressure. Gebremedhin et al (2001) reported that the differences in sweating rates were statistically significant at P < 0.05 between breeds, between black and white hair coats, and changes in solar load, relative humidity, and air velocity. Also wetting the skin surface and increasing air velocity profoundly increased evaporation rate by converting sensible heat to latent heat. Other factors can be summarized as follows: hair coat physical and optical properties, coat density and thickness, hair length and color, and skin color.
Dowling (1958) was the first to clearly demonstrate that sweating in cattle is important for thermoregulation. In the 1950s, bovine sweat glands were found to be apocrine and associated with hair follicles. However, there is no comprehensive data on the activity and properties of sweat glands based on recent technology results. It has been proposed that volatile organic compounds (VOCs) emitted by the living body can provide valuable information about the physiological state of the organism and thus generate a chemical signature to detect stress and disease states. Schleger et al. (1971) in their work in the rate of sweating between the micro-areas of beef skin emerged significant differences and morphological differences between these areas were investigated. Among the characters most closely related to sweating performance, follicle percentage and sweat gland layer were applied. Neither sweat gland volume nor follicle density had a direct effect on sweating rate. The growth phase of the hair follicle has a strong effect on capillary feeding into the sweat gland, and this appears to be a critical factor in sweat gland performance. Blazquez et al. (1994) in their study in the lumbodorsal, perineal and scrotal regions of cattle moisture evaporation rates in the skin, thermoelectric and high ambient temperature was measured. Evaporation rates of heifers and bulls in perineal and scrotal regions were higher than lumbodorsal areas (P <0.001). When the cows and bulls were transferred from the thermoneutral to a warm environment, the lumbodorsal evaporation rate increased significantly (P <0 001) and the evaporation rate in the bulls showed a similar increase; it was found that the rate of evaporation from the perineum of cows under the same conditions was lower (P <0.05). Nascimento (2015), stated that sweat glands are important in the thermoregulation of cattle and in addition they help to dissipate heat in the body. Studies on the histology of sweat glands are important in terms of heat removal and perspiration capacity and secretory potential, and the investigator has determined the glandular epithelial height, glandular length and sweat gland per cm2 of the three-year-old cattle by histomorphometry. Digital images were analyzed on a Trinocular BX40 Olympus microscope coupled with a connected Oly - 200 camera. Images were magnified with 2x, 4x, 10x and 40x magnification microscopes and measurements were evaluated using HL Image 97 program. Glandular epithelium height, depth of glands, length and density of glandular section per cm 2 were analyzed. Glandular epithelium of calves was higher than heifers (P = 0.0024) and cows (P = 0.0191). The depth of the gland was not affected by age and the secretion rates of cows were higher than heifers (P = 0.0379) and calves (P = 0.0077). Heifers were more sweat glands per cm2 skin (P = 0.023). In cattle, glandular epithelial height and density decreased as animals grew. In their study by. Johnson (1970) reported that the sweating rate of cattle B. indicus cross-bred cows had higher sweating rates than B. taurus cows at high air temperatures but the difference between the groups was not significant statistically also were generally highest on the shoulder and lowest on the lumbar region.
also researcher reported that the secretions from cattle skin at high ambient temperatures contained at least four to five times as much potassium as sodium and total sodium and potassium loss through the skin of these experimental animals at the highest ambient temperatures was estimated to be no more than 1–3 % of the sodium and potassium intake in the feed. Sweat also important criteria at hign temperature enviroment for heat stress combat. Sweating plays an important role in promoting heat loss from cattle under thermal stress. But Joshi et al (1970) reported that the low chloride secretion indicates that under hot conditions cattle do not have a need for large amounts of salt replacement in the diet. Atrian and Shahryar (2012), they stated that increased sweat is an important mechanism for reducing the body's excessive heat. They added that this mechanism leads to a decrease in body temperature, but this event causes many body electrolytes such as potassium to be ejected and acid-base imbalance of the body. They stated that water, sodium, potassium and chlorine are important elements of sweat and that sweating is the most important thermoregulation mechanism used to dissipate excess body temperature.
Conclusion
Animals emit a range of volatile and non-volatile molecules depending on their physiological state, ambient temperature, stress, diet and genetic conditions. A large number of volatile compounds can be emitted from different parts of the body. Limited study has been conducted to explain the mechanism of volatile odor compounds produced in the body, which is the most important compound for body odor. The sweat content of the cattle is capable of providing information on many physiological changes of the animal. However, there is a need for extensive studies on this subject in order to know what changes in sweat in which situation. The type of odor molecule have been studied widely in plants, bacteria and insects, and to a much lesser extent in vertebrates. But still detailed research required for more convenient aplication.
Acknowledgements
This work was supported by Çukurova University Scientific Research Projects Coordination Unit [ID: FBA-2018-10289)
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