Curcuma and Scutellaria baicalensis extracts reduced thermoregulatory behavior in chickens subjected to moderate heat stress

Abstract

Using phytogenic additives represents a new trend in the poultry feed industry because of purported beneficial impacts. There is limited information about the effects on chicken behavior, but based on new studies, some plant-based active compounds influence animal cognitive function. Therefore, the primary objective of this experiment was to investigate the impact of a feed additive consisting of a mixture of Curcuma and Scutellaria baicalensis on behaviors associated with exposure to heat stress in broiler chickens. Chickens before 21 days of age were kept in 12 littered floor boxes according to guidelines for Cobb 500 hybrid. The Cobb 500 chickens of both sexes were fed identical diets until they reached 21 days of age. From this point onward, the experimental group received in the diet a 0.1 % supplement containing Curcuma and Scutellaria baicalensis extracts. The control group received a feed mixture without phytogenic additives. Both groups had six replicates, and each group comprised 75 chickens. The pens of experimental and control group were randomly selected. The experimental period spanned from 28 to 35 days of age, during which the chickens were subjected to mild constant heat stress (28°C). Ethological observations were conducted at 31, 32, and 33 days of age, divided into three observation periods at the beginning, middle, and end of the daylight period (18 h) using the visual scan sampling method. After the experimental period at 35 days of age, chickens from both groups exhibited nearly identical live body weights and daily feed intake. However, the experimental group demonstrated significantly higher daily weight gain (P < 0.05). Thermoregulatory behaviors such as panting and wing spreading were suppressed (P < 0.05) in the experimental group, while there was a simultaneous increase in the number of chickens that were feeding (P < 0.05). Similarly, age significantly influenced behavioral patterns (P < 0.05), whereas time of the day only affected the number of chickens engaged in feeding (P < 0.05). In conclusion, the feed mixture enriched with Curcuma and Scutellaria baicalensis extracts exhibited performance-enhancing and behavior-changing effects, providing significant insights into the potential of this feed additive in improving performance and reducing thermoregulatory behavior manifestations within a flock under heat-stress conditions, thereby informing the poultry feed industry of a promising new development.