A study was conducted to determine the performance, carcase and gastrointestinal tract (gut) characteristics of broilers fed diets supplemented with dry peppermint (<I>Mentha piperita</I> L.) or thyme (<I>Thymus vulgaris</I> L.) leaves, which are among the alternative growth promoters. In the study, 312 one-week-old broilers (Ross-308) were used. There were 3 dietary treatments, each consisting of 4 replications (13 males and 13 females in each replication). The control group was fed basal diet, while the peppermint and thyme groups were fed diets supplemented with 0.2% peppermint or thyme (w/w) as menthol and thymol (70 mg per kg diet) sources, respectively. From 7 days to 35 days of age, the body weight gain was higher (<I>P</I> < 0.05) in broilers fed the peppermint-supplemented diet compared to the control, but the effect of peppermint on body weight gain disappeared at 42 days of age. Feed intake, feed to gain ratio, carcase weight, carcase yield, and the relative weights of the edible inner organs and whole gut, and the relative length of the whole gut were not significantly affected by peppermint and thyme contents. The peppermint or thyme leaves increased (<I>P</I> < 0.05) the abdominal fat pad at 42 days of age. Thus, the dry peppermint leaves had a higher growth promoting efficacy than the dry thyme leaves at an early stage of broilers’ life, but an increase in abdominal fat should be taken into account for carcase quality and processing.

Feeding with a diet containing HS caused a measurable variation in the meat quality and blood cholesterol as well as the performance, carcass, and gut traits of broilers.

This study was conducted to investigate the effect of dietary green tea extract (GTE) on the performance, carcass and gastrointestinal tract (gut) traits, caecal coliform bacteria count, and pH and color (CIE L*, a*, and b*) values of the breast muscle in broilers. A total number of 600 day-old broilers (Ross 308) was allocated to three treatments with four replicates containing 50 (25 males and 25 females) birds. The dietary treatments consisted of the basal diet as the control (0GTE) and diets with GTE at 0.1 (0.1GTE) or 0.2 (0.2GTE) g/kg. Body weights and the feed intake of broilers were measured at 1, 21 and 42 days, the feed intake was measured for different periods and the feed conversion ratio was calculated accordingly. At 42 day four birds per replicate were slaughtered for the determination of carcass and organ weights, caecal coliform bacteria count, and also quality of the breast muscle. The dietary GTE increased the body weight, feed efficiency, carcass weight and dressing percentage and decreased caecal coliform bacteria count of broilers (p<0.05). The 0GTE broilers consumed (p<0.01) less feed than the 0.1GTE birds in the entire experimental period. The relative abdominal fat weight and gut length of broilers in the 0.2GTE were tended to be lower (p<0.07) than those in the 0GTE group. The breast meat from 0.1GTE birds had a lower pH value when compared to that from 0GTE birds. The 0.1GTE broilers had lighter breast meat than 0GTE and 0.2GTE birds. The dietary GTE increased a * and b * values of the breast meat. Thus this product appeared to have a measurable impact on CIE color values of the breast meat in broilers. The results of the present study may indicate that the improved production results in the group with added GTE are directly connected with physiological mechanisms such as the regulation of the caecal micro-flora.

The effects of raw (GP) and fermented grape pomace (FGP) on the growth performance, some carcass parameters, antioxidant status, intestinal morphology, and selected bacterial species in broiler chicken were investigated in this study. Grape pomace was fermented with Aspergillus niger for 7 d. In total, 140 one-day-old male chicks (Ross 308) were randomly assigned to four treatment groups, with five replicates and seven birds each. Chickens were fed either a basal diet (CON) or the basal diet supplemented with 0.25 g/kg synthetic antioxidants (5% butylated hydroxytoluene, 1% butylated hydroxyanisole, and 11% ethoxyquin) (AO), or 15 g/kg GP (GP), or 15 g/kg FGP (FGP) for 42 d. Dietary GP raised serum glutathione peroxidase (p = 0.031) and superoxide dismutase (p = 0.021) levels, increased ileum lamina muscularis thickness (p = 0.016), and did not affect selected bacterial species in the cecum of broiler chickens. Dietary FGP improved body weight (p = 0.003), increased the serum catalase level (p = 0.032), and decreased the cecal Clostridium perfringens count (p = 0.033) but did not affect the ileal morphology of broiler chickens. The carcass parameters, malondialdehyde level, pH, and color of the breast meat of chickens were not changed by either GP or FGP supplementation. Chickens fed with the synthetic antioxidants had similar growth performance with the chickens fed with FGP but had better body weight (p = 0.003) and feed conversion ratio (p = 0.045) compared with the chickens fed with GP. The obtained results showed that FGP can be used as an alternative to synthetic antioxidants in broiler diets.

To evaluate the e ect of malic acid (MA) on performance and some digestive tract (gut) traits of Japanese quails, quails were divided into treatment groups each with replicates containing birds. While one of groups was fed a mash form basal diet with no additives ( MA), other groups were fed the diets with malic acid at . ( . MA), . ( . MA) or . ( . MA) g/kg from to d of age. The weight gains of . MA and . MA birds and the feed consumption of . MA were higher than those of MA. Addition of the malic acid to the diets did not a ect the feed e ciency. The . MA birds had a higher carcass weight compared to other groups. The . MA birds had a higher gut length compared to the MA. The results indicated that feeding diets with malic acid at . and . g/kg might increase weight gain and feed consumption without a ecting feed e ciency and a significant benefit of feeding diet with malic acid at . g/kg compared to the control diet was obtained in terms of carcass weight in the Japanese quails.