EFFECTS OF DIETARY THYME ON IMMUNE CELLS, THE ANTIOXIDANT DEFENCE SYSTEM, CYTOKINE CASCADE, PRODUCTIVE PERFORMANCE AND EGG QUALITY IN LAYING HENS

The study aims to investigate the effects of dietary supplementation of thyme on the antioxidant defence mechanisms, immune system, inflammatory cytokines, and production performance and egg quality traits in laying hens. A total of 120, 24-week-old Lohmann-Brown-Classic laying hens were used in this study. The experimental groups were fed on a ration containing 0.1%, 0.5%, and 1% thyme, respectively for 30 days while the control group received the standard chicken feed. Certain parameters such as feed conversion rate (g/g), egg production rate (%), egg mass (g/hen/day) and egg quality were evaluated. Furthermore, differential leukocyte count, heterophil/lymphocyte ratio and certain cytokine levels were assessed. Serum malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), ascorbic acid and glutathione peroxidase (GSH-Px) levels were measured to assess the effects of thyme on the antioxidant defence system. Serum interleukin-4 (IL-4) and GSH-Px activity levels decreased in the 0.1% and 0.5 % thyme groups, respectively compared to those of the control group (p <= 0.05). The leukocyte differential counts, as well as heterophil/lymphocyte ratio, did not differ significantly except for a gradual increase in leukocytes and a significant decrease in basophils with the increasing thyme concentration. Likewise, thyme supplementation did not affect performance parameters but exhibited a significant impact on egg yolk color intensity while shell weight, shell thickness, and breaking strength were negatively affected (p <= 0.05). It can be deduced that the thyme-supplemented diet did not elicit positive effects on either the antioxidant defence system or the downregulation of inflammation. That the hens experienced no difficulty in consuming the thyme-supplemented diet in the study is considered promising for further studies to be carried out, concerning the effects of higher concentrations of thyme

Can dried tomato and red pepper powder be used as a dietary supplement to strengthen defence systems and production performance in laying hens? Kann getrocknetes Tomaten-und Paprikapulver als Nahrungsergänzungsmittel zur Stärkung der Abwehrsysteme und der Produktionsleistung von Legehennen verwendet werden?

In this study, effects of dietary supplementation of dried tomato powder (DTP) and red pepper powder (DPP) on the antioxidant mechanisms, immune system, cytokines, egg production performance, and egg quality were investigated in a total of 90, 30-week-old hens. The study groups were fed on a diet containing 4% DTP and 4% DPP, respectively for 30 days, while the control group received a commercial laying hen feed. Egg production and egg quality parameters, differential leukocyte count, heterophil functions, serum cytokine, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), ascorbic acid, and glutathione peroxidase (GSH-Px) levels were measured. It was determined that serum tumor necrosis factor-alpha (TNF-α) levels increased (P = 0.018) and heterophil (P = 0.033) and monocyte (P = 0.020) percentages decreased in the DPP group compared to both control and DTP groups. In the same hens, serum transforming growth factor-beta (TGF-β) level (P = 0.029) and oxidative burst (P = 0.021) increased compared to the control group, but interleukin-4 (IL-4) (P = 0.014) level and SOD activity (P = 0.021) increased compared to the DTP group. Phagocytic activity was higher in the DTP group compared to other groups (P = 0.003). In addition, it was observed that serum catalase level (P = 0.008), and egg yolk colour (P = 0.001) increased in both experimental groups compared to the control group. It was concluded that DPP and DTP used in this study strengthen the antioxidant defence system, increase heterophil functions, and positively affect cytokine production and egg colour, so it can be used as a safe feed additive in chickens

Optimal Linear Combinations of Overlapping Variance Estimators for Steady-State Simulation

Abstract To estimate the variance parameter (i.e., the sum of covariances at all lags) of a steady-state simulation output process, we formulate an optimal linear combination of overlapping variance estimators (OLCOVE). Each variance estimator is computed from the same data set using one of the following methods: (i) overlapping batch means (OBM); or (ii) standardized time series (STS) applied to overlapping batches separately and then averaged over all such batches. Each estimator’s batch size is a fixed real multiple (at least unity) of a base batch size, appropriately rounded. The overall sample size is a fixed integral multiple of the base batch size. Exploiting the control-variates method, we assign OLCOVE coefficients so as to yield a minimum-variance estimator. We establish asymptotic properties of the bias and variance of OLCOVEs computed from OBM or STS variance estimators as the base batch size increases. Finally, we use OLCOVEs to construct confidence intervals for both the mean and the variance parameter of the target process. An experimental performance evaluation revealed the potential benefits of using OLCOVEs for steady-state simulation analysis.