BACKGROUND: Although numerous reports support the beneficial effects of supplementing chromium (Cr) on broiler performance under normal and stress conditions, the optimal level has not been determined yet. OBJECTIVES: This study was conducted to investigate the effects of different levels of supplemental Cr on performance, cortisol, and thyroid hormones of broiler under normal and stress conditions. METHODS: A total of four hundred forty-eight broilers were used. Broilers allocated into 2×4 factorial experiment included: stress (normal and stress) and 4 levels of supplemental chromium (0, 1000, 2000, 3000 ppb) since day 18. A completely randomized design with 8 treatments and 4 replicates (14 birds per replicate) was used. Dexamethasone used as a stressor for one week (stress period, STP) then experiment continued to day 46 (recovery period, RCP). RESULTS: Feeding 1000 and 2000 ppb Cr improved feed conversion ratio (FCR) and increased T4 compared to 0 and 3000 ppb Cr in stressed broilers in STP (P<0.05). Feed intake (FI), body weight (BW) and T3 concentration were higher in broilers fed with 1000 ppb Cr in the diet and reared without stress in STP (P< 0.05). Despite the negative effect of stress on performance in RCP, dexamethasone-stressed broilers had better FCR. Feeding stressed birds with 1000 ppb Cr increased blood cortisol whereas it reduced cortisol in the normal-reared birds. CONCLUSIONS: The Dietary supplementation of 1000 and 2000 ppb Cr reduced deleterious effects of physiological stress. Moreover, 1000 ppb Cr improved FI and BW of broilers under normal condition at first week. Feeding high level of chromium under normal and stress conditions did not improve the performance.

Neutrophils were purified from blood of dexamethasone-treated (0.04 mg/kg of body weight) and untreated calves. Cells were untreated (controls) or cultured in media containing 5 or 10 ng of bovine recombinant granulocyte-macrophage colony-stimulating factor (rbGM-CSF)/ ml for 10 to 12 hours before being tested for various functions. Dexamethasone treatment of calves decreased luminol-dependent chemiluminescence, decreased phagocytosis of Pasteurella multocida and several Staphylococcus spp by various degrees, and decreased antibody-dependent cell-mediated cytotoxocity against bovine herpesvirus-infected cells by 26 to 32%. The percentage phagocytosis of coagulase-positive S aureus and S intermedius was higher than that of coagulase-negative S epidermidis for neutrophils from all calves. Culture of neutrophils with rbGM-CSF significantly increased (P < 0.05) all of the aforementioned functions, compared with control neutrophils; however, rbGM-CSF-induced increases in function tended to be higher in neutrophils from dexamethasone-treated calves than in neutrophils from untreated calves.

This study investigated dexamethasone (DXM) residues in the milk from intramuscularly dosed dairy cows and established the withdrawal time (WT) of DXM in milk. Eighteen healthy Holstein cows were injected with 20 (DXM-1) or 40 mL (DXM-2) of a drug containing 1 mg/mL of DXM. After administering DXM, milk samples were collected from all cows at 12-hour intervals for five days. The DXM residue concentrations in milk were determined by liquid chromatography-tandem mass spectrometry. The correlation coefficient of the calibration curve was 0.9966, and the limits of detection and quantification (LOQ) were 0.03 and 0.1 μg/kg, respectively. The recoveries were 97.0% to 104.0%, and the coefficient of variations was less than 7.22%. After treatment, DXM in DXM-1 was detected above the LOQ in two milk samples at 36 hours and below the LOQ in all milk samples of DXM-2 at 48 hours. Using the WT calculation program WT 1.4, the withdrawal periods of DXM-1 and DXM-2 in milk were established to be two days. In conclusion, the developed analytical method is sensitive and reliable for detecting DXM in milk. The estimated WT of DXM in bovine milk is shorter than the current milk WT recommendation of three days for DXM in lactating dairy cows.

To study the effect of over dosages of dexamethasone on eye rabbits; a total of 20healthy adult rabbits were used. Rabbits were equally divided in to 4 groups, therabbit in each group wastreated with dexamethasone intramuscular twice daily for 30days. The dexamethasone doses were10, 20, 30, and 40 mg/kg/day, for group 1, 2, 3,and 4 respectively. After that the animals were sacrificed, histological sections ofcornea samples were prepared using hematoxylin and eosin staining. The entireexperiment was completed in the animal facility at Veterinary Medicine College,University of Basrah. Rabbits in Group 1 and 2 remain healthy and there are no sideeffects of dexamethasone while group 3 and 4 the side effects of dexamethasone werecataract and emaciation. The cataract was clear clinically and histologically. Thedevelopment of dexamethasone-induced cataract need much work to elucidate themechanism

Objective: To evaluate a human radioimmunoassay (RIA) and equine and high-range porcine (hrp) species-specific ELISAs for the measurement of high serum insulin concentrations in ponies. Samples: Serum samples from 12 healthy nonobese ponies (7 clinically normal and 5 laminitis prone; 13 to 26 years of age; 11 mares and 1 gelding) before and after glucose, insulin, and dexamethasone administration. Procedures: Intra-and interassay repeatability, freeze-thaw stability, dilutional parallelism, and assay agreement were assessed. Results: Assay detection limits were as follows: RIA, < 389 μU/mL; equine ELISA, < 175 μU/mL; and hrp ELISA, 293 to 8,775 μU/mL. Mean ± SD intra- and interassay repeatability were respectively as follows: RIA, 6.5 ± 5.1 % and 74 ± 3.4%; equine ELISA, 10.6 ± 11.0% and 9.0 ± 4.6%; and hrp ELISA, 19.9 ± 172% and 173 ± 16.6%. Freezing and thawing affected measured concentrations. Dilutional parallelism in the RIA was only evident when insulin-depleted equine serum was used as a diluent (percentage recovery, 95.7 ± 274%); in the ELISAs, dilutional parallelism was observed when a zero calibrator was used. Agreement between RIA and equine ELISA results was good for samples containing concentrations < 175 μU of insulin/mL (bias, −18.5 ± 25.5 μU/mL; higher in RIA). At higher concentrations, assay agreement was poor between RIA and equine ELISA results (bias, −185.3 ± 98.7 μU/mL) and between RIA and hrp ELISA results (bias, 25.3 ± 183.0 μU/mL). Conclusions and Clinical Relevance: Agreement among results of the 3 assays was variable, and dilutional parallelism was only evident with the RIA when insulin-depleted equine serum was tested. Caution is recommended when evaluating high insulin concentrations measured with the RIA or ELISAs.

study was conducted to evaluate the usage of dexamethasone (Dx) in the treatment of liver function tests in experimental paraquat (PQ)- induced oxidative stress in male albino rats. Three groups of rats were subjected to this trial, control, PQ group (50 mg/ kg orally) and PQ with Dx (50 mg/ kg orally, 4 mg/ kg ip. Respectively)daily throughout the 15 days. Results revealed that treatment with PQ caused a mortality rate in a ratio of 30%,significantly increased (p≤0.05) of glucose, cholesterol, bilirubin concentrations and alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and amylase activities but the concentrations of both triglycerides and serum proteins were reduced compared with control whereas the treatment of PQ- treated rats with Dx decreased mortality rate (30%) and corrected the activity of serum transaminases, alkaline phosphatase enzymes whereas Dx treatment induced an elevation in amylase activityin addition to the elevation of concentrations of total cholesterol, total protein and albumin in comparison with values of PQ- treated rats, Dx did not affect the concentration of glucose. In conclusion, the treatment of PQ- induced toxicity with Dx in rats was efficient in correction of most liver function tests.