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

Effects of day-of-hatch intramuscular administration of a herbal extract mixture and its re-supplementation in drinking water on growth performance, stress indicators, and antioxidant status of broiler chickens reared under hot summer conditions

Broilers under oxidative stress from high ambient temperatures may benefit from the use of additives that have antioxidant properties. This experiment investigated the efficacy of a herbal extract mixture (HEM; aqueous extracts from Ferula gummosa, Thymus vulgaris, and Trachyspermum copticum) in day-old chicks, injected intramuscular (deep pectoral muscle; (0, 30, 60, and 90 μL/0.1 mL of sterilized and distilled water)), and supplemented in drinking water (0 and 0.25 mL/L) during the rearing period. Broilers were reared in battery cages under summer temperature conditions, with average maximum temperature of 35.5°C, average minimum temperature of 25.5°C, and average relative humidity of 50-60%. A total of 400 1-day-old Ross 308 male broiler chicks were randomly assigned to 8 treatment groups (5 replicates/treatment with 10 birds per replicate). From d1 to d10, the indoor air temperature was adjusted to match fluctuating outdoor summer temperatures, and was set at 30-34°C and 50-60% relative humidity; and from d10 onwards, no adjustments were made. Injection of HEM linearly decreased feed:gain (P = 0.005), heterophile-to-lymphocyte (H/L) ratio (P = 0.007), and serum concentrations of cholesterol (P = 0.008), low-density lipoprotein cholesterol (LDL) (P < 0.001), malondialdehyde (P = 0.005), and cortisol (P = 0.008). The 60 μL of HEM injection produced the best results in terms of final body weight (BW; P = 0.003), overall average daily gain (ADG; P = 0.002), European performance index (P < 0.001), carcass yield (P < 0.001), and serum glutathione peroxidase activity (P < 0.001). Supplementation of HEM in drinking water also increased final BW (P = 0.048), overall ADG (P = 0.047), high-density lipoprotein cholesterol (P = 0.042), and total antioxidant capacity (P = 0.030), while decreasing the H/L ratio (P = 0.004) and serum LDL concentration (P = 0.031). There were interactions between injection and water supplementation for BW (day 24; P = 0.045), carcass yield (day 42; P = 0.014), and serum superoxide dismutase activity (day 42; P = 0.004). In conclusion, administering an injection of HEM at a dose of 60 μL at the time of hatching, followed by supplementation at a dose of 0.25 mL/L via drinking water during the rearing period could be a useful strategy for improving the performance and health status of heat-stressed broiler chickens.

The Impact of Herbal Additives for Poultry Feed on the Fatty Acid Profile of Meat

Researchers often found that herbal additives to chicken feed can favorably alter the fatty acid profile of the meat. The most desirable effects of diet modification comprise an increased content of polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) and a reduced content of saturated fatty acids (SFA) in the breast and thigh muscles. A modified fatty acid profile contributes to improvement in the quality of poultry meat, which is reflected in its increased consumption. However, it may be problematic that PUFAs are oxidized easier than other lipids, which can have a negative impact on the sensory traits of meat. By contrast, herbs and herbal products contain antioxidants that can prevent the oxidation of unsaturated fatty acids and cholesterol present in animal-origin products and increase the antioxidant potential of the consumer’s body. This paper aims to review the influence of herbal additives for broiler chicken diets on the fatty acid profile of poultry meat. Special attention was paid to changes in the content of SFAs, MUFAs, and PUFAs, but also alterations in the omega-6:omega-3 ratio. The presented reference literature supports the statement that herbs and bioactive components of herbs added to chicken diets can improve the quality of broiler chicken meat by altering the content of fatty acids.