Herbal extract dietary supplementation effect on growth performance and meat quality in broiler raised under two stocking densities

Abstract The number of birds or their total live weight in relation to a given area is known as stocking density; higher stocking densities will cause more stress to the birds, which may have an impact on their physiological state, productivity, carcass quality, growth performance, immunity, metabolism, and meat quality. The present study aimed to investigate the potential impact of 2 different stocking densities on growth performance, carcass characteristics, meat quality, serum, and expression of Insulin like growth factor-1 (IGF-1), muscle regulatory genes expression and serum biochemical indicators of broilers supplemented with essential oils (EO). In total, 784-day-old chicks of Ross 308 were randomly assigned into 4 different groups with 7 replicates for each: Normal feed (no essential oils [EO] added) and normal stocking as 9 bird/m2, (NSD). Normal feed (no essential oils [EO] added) and high stocking as 14 bird/m2, (HSD). Feed with essential oils (Digestarom DC® 150 g/Ton of feed) and normal stocking as 9 birds/m2, (NSD + EO). Feed with essential oils (Digestarom DC® 150 g/Ton of feed) and high stocking as 14 birds/m2, (HSD + EO) for 35 days. Bodyweight was recorded at the beginning of the trial and then at the end of each week, feed intake was recorded at the end of each week as well. A total of 28 birds (7 birds per treatment) birds were slaughtered at 35 days of age to evaluate each parameter. The HSD group had the lowest (P