1. The present study was aimed to investigate the effect of adding ascorbic acid or α-lipoic acid to to the diet of broilers exposed to heat stress on performance and meat quality. 2. Heat stress caused a decrease in final body weight and feed consumption, whilst ascorbic acid (AA) and α-lipoic acid (ALA) partly prevented the decrease in final body weight of males. 3. While heat stress increased the pH values of broiler drumsticks and breast meat, AA and ALA partly reduced this increase. For meat quality, AA and ALA reduced the adverse effects on the relative yellowness value, particularly on d 14 of storage. 4. It was determined that heat stress affected the microbiological quality of meat adversely, and that AA and ALA alleviated this effect to a certain extent. 5. In conclusion, while heat stress affected body weight gain and meat quality adversely, the supplementation of the ration with AA and ALA partly alleviated these adverse effects.

This study was conducted to determine the effect of diets containing different levels of thyme essential oil (TEO) on performance, some serum parameters and the antioxidative metabolism of the serum and liver tissues in quails. A total number of 200 sixteen-days-old Japanese quails (Coturnix coturnix japonica) were used in the study. The animals were divided into 4 groups; the control group was fed only basal diet but groups TEO1, TEO2 and TEO3 had thyme essential oil of 150, 300 and 450 mg/kg, respectively, added to their diets. Body weight and daily weight gain increased with higher levels of thyme essential oil in the feed, yet a statistically significant increase was detected in only group TEO3 (p<0.05). Furthermore, in all of the groups that were fed on TEO, feed intake was significantly higher than that of the control group (p<0.05). In the groups that received thyme essential oil, serum creatinine and low-density lipoprotein (LDL) levels were low, whereas serum magnesium levels were high (p<0.05). Thyme essential oil significantly increased in liver catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and serum CAT and GSH-Px activities, and significantly reduced both liver and serum lipid peroxidation (malondialdehyde=MDA) levels (p<0.01). In result, while thyme essential oil partially affected the performance and serum parameters, it had a marked effect on the antioxidant metabolism.

1. This study was designed to determine the effects of heat stress exposure on broiler fattening performance, meat quality and microbial counts. 2. Six groups were established: CHP (24°C+210 g/kg crude protein (CP)), SHP (34°C+210 g/kg CP), CLP (24°C+190 g/kg CP), SLP (34°C+190 g/kg CP), SHPVE (34°C+210 g/kg CP+Vitamin E) and SLPVE (34°C+190 g/kg CP+Vitamin E) groups. 3. It was determined that the body weights of the male animals included in Group CHP displayed statistically significant differences in comparison to those of Groups SHP, CLP and SLP. Furthermore, it was ascertained that the values of Group CLP also displayed statistically significant differences in comparison to those of Groups CHP, SHP and SLP. The feed consumptions in Groups CHP and CLP were significantly different from those of the remaining groups, excluding Group SHP. The highest feed conversion rate was determined in Group SHPVE. 4. When evaluated for chicken drumstick TBA values, Group CHP differed significantly from Groups SHP, SHPVE, CLP and SLP, whilst Group CLP differed significantly from Groups SHP, SHPVE and SLP. On the other hand, when evaluated for breast meat TBA values, Group CHP displayed statistically significant differences in comparison to Groups SHP, SLP and SLPVE, whilst Group CLP differed significantly from Groups CHP, SHP, SLP and SLPVE. 5. The sensitivity of breast meat to colour susceptibility was greater than that of chicken drumsticks. While storage period affected the TBA values and microbial counts of meat significantly, its effect on colour parameters was found to be variable. Trial groups significantly affected total aerobic mesophilic bacteria counts in chicken drumsticks, and Enterobacteriaceae and total aerobic mesophilic bacteria counts in breast meat. 6. In conclusion, heat stress adversely affected final body weights and the lipid oxidation of meat, whilst vitamin E alleviated these adverse effects.

Fucoxanthin is a major carotenoid found in marine brown algae. This study investigated the impact of fucoxanthin on the growth performance, antioxidant metabolism and meat quality of broilers. Overall, 180 one-day-old male broiler chicks (Ross 308) were assigned to one control group (CONT) and 2 treatment groups (FUCO1 and FUCO2), with six replicates of 10 birds each. The CONT, FUCO1 and FUCO2 birds were fed a basal diet supplemented with 0, 100 and 200 mg/kg of fucoxanthin, respectively. Average body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR) were similar among the groups. Fucoxanthin increased catalase (CAT) and superoxide dismutase (SOD) activities and glutathione (GSH) levels (p<0.01), and reduced malondialdehyde (MDA) levels (p<0.01) in the liver, breast and drumstick tissues. The effects of fucoxanthin on drumstick yellowness (b*) on day 3 and water activity (a w) on day 5 and breast lightness (L*) on day 3 b* values days 2 and 5 were limited and variable. While fucoxanthin showed antimicrobial effect against Staphylococcus spp. in the breast meat on days 5 and 6 of storage (p<0.05), its effects at different time periods and against other microorganisms varied. In conclusion, fucoxanthin did not affect performance parameters, but had a significant impact on antioxidant metabolism, and showed a limited effect on the microbial quality of meat.

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