The Effect of Adding Herbal Extracts to Drinking Water on Body Temperature, Level of Thyroid Hormones and H:L Ratio in the Blood of Broiler Chickens Exposed to Elevated Ambient Temperature

Abstract

The aim of the study was to determine the effect of supplementing drinking water with extracts from lemon balm, sage and nettle on body temperature, level of thyroid hormones and the heterophil to lymphocyte (H:L) ratio in the blood of broiler chickens exposed to elevated rearing temperature. One-day-old Ross 308 chicks were divided into four groups: group I (CON) and experimental groups II (LB), III (S) and IV (N), in which, from 22 to 42 days of rearing, drinkers were supplemented with lemon balm extract, sage extract or nettle extract (2 ml/l water), respectively. In addition, at 5 weeks of growth, all the groups were exposed to elevated ambient temperature (up to 30°C) for 5 days, after which the recommended thermal conditions were reinstated. During the study, mortality, rectal temperature and radiated temperature of the broilers were monitored. Blood was collected from 10 birds per group to determine the concentration of thyroid hormones (T3 and T4) and to make blood smears. The H:L ratio was determined based on the percentage of heterophils (H) and lymphocytes (L). The herbal extracts from lemon balm, sage and nettle, added to drinking water at 2 ml/l, reduced the blood level of the thyroid hormone (triiodothyronine) and rectal temperature in the experimental broilers during the initial period of thermal stress. Chickens receiving the nettle extract were also characterised by lower radiated temperature of the unfeathered body, a lower H:L ratio in the blood during the increase in ambient temperature, and the lowest mortality percentage. It can therefore be considered that the dietary supplementation of nettle, in the form and concentration used in this study, had the most favourable effect on the physiological status of the birds (body temperature, level of thyroid hormones and H:L ratio) ratio exposed to elevated ambient temperatures (30oC), and thus on their welfare.

Effect of Rearing Technology on Production Performance, Selected and Blood Parameters and Welfare Levels of Broiler Chickens During the Summer Production Cycle

“…Some studies have shown that the addition of natural antioxidants to the diet of broiler chickens results in a slowing of basal metabolism and a significant decrease in body temperature (Ragab et al, 2013;Morovat et al, 2016;Skomorucha and Sosnówka-Czajka, 2021). However, in our study, the addition of 2 ml/l of mixed herbal extract to water had no effect on thyroid hormone levels and body temperature of broiler chickens.…”

“…Similarly, in our study, the addition of 2 ml/l of herbal mixture extract to the water contributed to lower corticosterone levels in the blood of HE birds on day 35 of the experiment compared to the CON control group. The diet of birds supplemented with herbs can also affect glucose levels (Skomorucha and Sosnówka-Czajka, 2014;Morovat et al, 2016) and the magnitude of the H:L ratio (Khafar et al, 2019;Skomorucha and Sosnówka-Czajka, 2021). However, in our study, no change in glucose levels or the magnitude of the H:L ratio was observed under the influence of dietary mixed herb extract.…”

“…On the first day of life, the chicks, after being weighed and marked with chick tags, were allocated to three groups (200 birds per group), each consisting of five subgroups (40 birds per subgroup). In groups I (CON) and II (HE), broiler chickens were kept on litter without outdoor access; additionally, in group II, birds from days 22 to 42 of rearing were given a liquid alcoholic extract of a mixture of herbs (50% Melissa officinalis L. and 50% Urtica dioica L.) in water drinkers at 2 ml/l water (Skomorucha and Sosnówka-Czajka, 2021). In group III (AP), birds were reared on litter with free-range access from day 1 of rearing (Table 1).…”

“…vulnerability to stress (Skomorucha and Sosnówka-Czajka, 2013 a). A number of authors have also reported positive effects of the addition of herbs to the diet on the body of broiler chickens reared under conditions of elevated air temperatures (Attia et al, 2018;Song et al, 2018;Skomorucha and Sosnówka-Czajka, 2021).…”

Impact of Feeding Broiler Chicks on Ginger, Peppermint and Vitamin C Under Heat Stress Conditions

“…Breast meat can be regarded as an important component of a healthy diet as it contains more polyunsaturated fatty acids (PUFA) and less saturated fatty acids (SFA) than meat from other species of animals, e.g., beef and lamb (Berzaghi et al, 2005). Herbs and herbal products contain antioxidants that can prevent the oxidation of UFA and cholesterol present in animal-origin products such as meat and eggs (Orczewska-Dudek et al, 2020) and increase the antioxidant potential of the animal's body (Skomorucha, and Sosnówka-Czajka., 2021).…”