In this study, 160 73-week-old laying hens (HyLine W-36) were used to investigate the changes in production performance and egg quality parameters of aged laying hens after injection of different doses of growth hormone (GH) and a fixed dose of testosterone (Ts). The hens were weighed individually, placed in laying cages and then randomly assigned to four treatments with four replicates of 10 birds each, in a completely randomised design. The experiment was started at the 75th week and lasted until the 82nd week of age. The treatments were: 1: injection of 100 µL distilled water (control group), 2: injection of 500 µg Ts/kg liveweight + 50 µg GH/kg liveweight, 3: injection of 500 µg Ts/kg liveweight + 100 µg GH/kg liveweight and 4: injection of 500 µg Ts/kg liveweight + 150 µg GH/kg liveweight. In this study, ovulation rate (egg production percent), egg mass and feed intake were significantly higher in Treatment 3 than the control group (P < 0.05), and in Treatment 4, feed conversion ratio was significantly higher than for the other experimental groups (P < 0.05). In addition, the birds in Treatment 3 showed greater egg weight, albumen height, eggshell weight, eggshell density and eggshell weight per surface area than the control group (P < 0.05). In Treatment 3, egg length significantly increased compared with Treatments 1 and 4 (P < 0.05), and in Treatments 2 and 4, shell breaking strength was significantly lower than for the control group (P < 0.05). In conclusion, our results showed positive effects of GH and Ts administration on egg quality parameters and production performance in aged laying hens. Taken together, in the present study Treatment 3 was found more effective in improving egg quality and production performance of the old laying hens.

Plascencia (2017) The effects of consumption of β2-agonist zilpaterol hydrochloride (ZH) were evaluated on hormonal blood metabolites (insulin, cortisol and thyroids), haemoglobin, haematocrit, plasma volume, heart rate and respiratory changes in male goats in the finishing phase. For this, 16 Mahabadi castrated male goats were used in a completely random design to evaluate the effects of treatments. Goats which were fed a finishing basal diet for 60 days prior to start the experiment were subsequently supplemented during 30 days with ZH at a dosage of 0.0 or with 20 mg ZH/kg LW. Haemoglobin concentration and haematocrit levels were recorded at 10-day intervals of experiment. Plasma volume was calculated using the haematocrit value. Heart and respiratory rates were recorded at 10-day intervals of experiment. Rates were recorded at 1-h intervals between 06:00 and 18:00 h. Hormonal profiles were measured at days 1 and 30. Plasma volume, heart and respiratory rates increased (P < .001) in the ZH group. Zilpaterol supplementation increased (P < .04) plasma insulin, and thyroids hormones, but decreased (P < .01) haemoglobin, haematocrit value and cortisol hormones. It can be concluded that zilpaterol supplementation of 0.20 mg ZH/kg LW significantly influences blood metabolic hormones concentrations, plasma volume, and cardiovascular and respiration rates. ARTICLE HISTORY

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Background Ovarian chronic inflammation has been known to incidence in the laying hen mainly via increasing laying frequency and microbial infection, especially during late stage of production period. This study was aimed to evaluate beta-2 adrenergic agonist (Beta-2 Adrenergic Agonist, BAA) Salmeterol and beta blocker (Beta Blocker, BB) Propranolol on the gene expression of the ovarian pro- and anti-inflammatory mediators, inflammatory responses of immune system, ovarian functions and, hormones in the laying hens on the late stage of production period. Forty-eight White Leghorn hens aged 92 weeks were used for 4 weeks to be supplemented by Salmeterol and Propranolol. Ovulation rate and follicular growth were determined based on laying frequency and ovarian visual evaluation, respectively; the mRNA expressions of follicular beta-2 adrenergic receptor (Beta-2 Adrenergic Receptor, β2ADR), cyclooxygenases (Cyclooxygenases, COX) 1 and 2, and cytokines were measured by real-time PCR. The plasma concentration of ovarian hormones, cellular, and humoral immune responses were measured via ELISA, heterophil to lymphocyte ratio (Heterophil to Lymphocyte ratio, H:L), and sheep red blood cell (Sheep Red Blood Cell, SRBC) test, respectively. Results As compared to control, both of BAA Salmeterol and BB Propranolol resulted in a significant decrease in the mRNA expression of β2ADR, cyclooxygenases, and pro- and anti-inflammatory cytokines (P < 0.01). A significant elevation was observed in the ovulation rate (P < 0.05), plasma estradiol content on both treated groups (P < 0.05), and the content of progesterone and was just significantly (P < 0.05) increased in Salmeterol group. H:L was reduced in BAA group (P < 0.05), and immunoglobulin (Ig) M was elevated in both treated hens, when compared to control. The results indicated that Salmeterol significantly increases body weight (P < 0.05). Conclusion The stimulation and inhibition of beta-2 adrenergic signaling could reduce ovarian inflammatory condition in addition to enhancing laying efficiency in the aged laying hens.

To evaluate the influence of zilpaterol hydrochloride (ZH) supplementation on growth performance, carcass traits, chemical characteristics of the longissimus muscle (LM), and plasma metabolites, 16 Mahabadi castrated goats (29.93 ± 1.84 kg) were individually fed a finishing diet without or with ZH supplementation dosed at 0.20 mg/kg BW daily. Zilpaterol was fed for 30 days with 3 days of withdrawal before harvest. Compared with the controls, ZH supplementation decreased dry matter intake and increased total weight gain, average daily gain, and gain for feed. Hot carcass weight, dressing percentage, and LM area were increased, but back fat thickness and kidney-pelvic fat were reduced in the group that received ZH. Supplemental ZH did not affect the full viscera mass or stomach complex, but it increased empty body weight (EBW) and reduced (as g/kg final EBW) the heart/lungs and kidney weights. Zilpaterol supplementation increased LM protein and moisture and decreased LM fat. The goats fed with ZH had lower serum concentrations of glucose, triglycerides, and cholesterol than the controls. It can be concluded that daily ZH supplementation at 0.20 mg/kg BW increases growth performance, feed efficiency, and dressing percentage in castrated goats as a result of greater muscle accretion and causes reduction of fat and visceral organ mass.