The effects of haemolysis on serum chemistry measurements in poultry

Novel goose-origin astrovirus infection in geese: the effect of age at infection

Since 2017, a serious infectious disease characterized by visceral gout has emerged in China's main goose-producing regions. The disease has caused huge economic losses to China's goose industry. In our previous study, we determined that the pathogen causing gout in goslings is a novel goose-origin astrovirus, designated as AStV/SDPY/Goose/1116/17 (AStV-SDPY) strain. To investigate the effect of host age on the outcome of novel goose-origin astrovirus infection, 200 1-day-old healthy goslings were selected to be experimentally infected at 1, 5, 15, 25, and 35 D of age. It was shown in experimental infection that the AStV-SDPY strain was highly pathogenic in goslings aged 1 to 15 D, causing growth repression, severe visceral urate deposition, and even death, whereas goslings infected at 25 and 35 D of age showed mild symptoms. Histopathologic examination indicated that lesions occurred mainly in the kidney and liver of infected goslings, which is correlated to the severity of clinical signs and gross lesions. Viral RNA was detected in all representative tissues, and virus shedding was detected continuously within 15 D after inoculation. Higher viral copy number, especially in vital organs such as the liver and kidney, was developed in the goslings infected at 1 to 15 D of age than older geese. In addition, clinical chemistry and inflammatory cytokines showed that younger geese are more sensitive to AStV infection. Overall, our study demonstrates that the pathogenicity of AStV-SDPY in goslings is partly associated with the age of infection, laying a foundation for further study of the pathogenic mechanism of this virus.

Safety evaluation of zinc methionine in laying hens: Effects on laying performance, clinical blood parameters, organ development, and histopathology

The study was conducted to investigate whether high-dose zinc methionine (Zn-Met) affected the safety of laying hens, including laying performance, hematological parameters, serum chemical parameters, organ index, and histopathology. A total of 540 20-week-old Hy-Line White laying hens was randomly allocated to 6 groups with 6 replicates of 15 birds each. Birds were fed diets supplemented with 0 (control), 70, 140, 350, 700, or 1,400 mg Zn/kg diet as Zn-Met. The experiment lasted for 8 wk after a 2-week acclimation period. Results showed that dietary supplementation with 70 or 140 mg Zn/kg diet as Zn-Met significantly increased average daily egg mass (ADEM), laying rate (LR), and feed conversion ratio (FCR) (P < 0.05) and lowered broken and soft-shelled egg ratio (BSER) (P < 0.05) in comparison with the control group; no significant differences were detected among hens fed with 0, 350, or 700 mg Zn/kg as Zn-Met (P > 0.05); hens administered 1,400 mg Zn/kg showed a significant increase in BSER and remarkable decreases in ADEM, LR, and FCR (P < 0.001). There were no significant differences among hens receiving 0, 70, 140, 350, or 700 mg Zn/kg as Zn-Met in serum chemical parameters (P > 0.05); supplementation with 1,400 mg Zn/kg as Zn-Met remarkably elevated the concentrations of serum total bilirubin (TBILI), glucose (GLU), uric acid (UA), and creatinine (CRE) (P < 0.001), and enhanced activities of serum glutamic oxalacetic transaminase (GOP) and alkaline phosphatase (AKP) (P < 0.001) compared with the control group. No significant histopathological changes were found in hens administered 0, 70, 140, 350, or 700 mg Zn/kg as Zn-Met, while significant histological lesions were observed in the heart, liver, lung, and kidney tissues of hens receiving 1,400 mg Zn/kg as Zn-Met. No significant differences were detected in hematological parameters or organ index (P > 0.05). In conclusion, a nominal Zn concentration of 700 mg/kg as Zn-Met is considered to be no-observed-adverse-effect level following daily administration to hens for 56 days.

Comparison of moulting methods for layers: high-zinc diet versus fasting

The serum biochemical profiles, thyroid hormones, body weights and the production and quality of eggs subsequent to moulting, were compared in laying hens subjected to conventional forced moulting or forced moulting with a diet high in zinc. A total of 200 Dekalb White laying hens in their second production cycle were studied. Blood sampling was conducted in a factorial experimental design (2 × 3) with two methods of moulting (fasting or zinc) and three sampling periods (pre-moult, moult and subsequent peak). Total egg protein content, including globulins, was greater with the zinc diet, whereas egg weight and albumen percentage were greater after fasting. The zinc method resulted in an increased shell thickness and calcium percentage but lower percentage of phosphorus. During the moulting period, the hens in the zinc group had heavier mean body weights. It was concluded that moulting with a high-zinc diet could replace fasting, without negative effects on body weight, biochemical variables or subsequent egg quality and production. The zinc method was also better for the birds' welfare.

Effects of blood sample mishandling on ELISA results for infectious bronchitis virus, avian encephalomyelitis virus and chicken anaemia virus

This study determined the effect of sample mishandling on the performance of ELISAs for detection of antibodies against infectious bronchitis virus (IBV), avian encephalomyelitis virus (AEV) and chicken anaemia virus (CAV) in the serum of chickens. The effects of five different sample mishandling treatments were assessed: heat treatment, repetitive freezing and thawing and three levels of severity of haemolysis. These mishandling treatments simulated different conditions that might occur during routine blood collection, transport or storage in a clinical practice setting. Each mishandling treatment was experimentally applied under laboratory conditions and then samples were assayed for antibodies against IBV, AEV and CAV using commercial ELISA kits. Severe haemolysis had the most consistent detrimental effect on ELISA performance, producing results that were significantly different from the reference standard in all three ELISAs, although the direction of the effect varied (less positive for the IBV and CAV assays; more positive for the AEV assay). Moderate levels of haemolysis had a similar, but less consistent, effect to that of severe haemolysis, producing results that were significantly different from the reference standard only for the IBV (less positive) and AEV (more positive) ELISAs. Repetitive freeze-thawing also produced a significant effect on ELISA results for IBV (less positive) and AEV (more positive). The IBV ELISA appeared to be most susceptible to the effects of serum maltreatment. The findings from this study suggest that unpredictable variation in the results of ELISAs can occur due to different sample mishandling treatments.

Pretraining enhances recovery from visuospatial deficit following cerebellar dentate nucleus lesion

Following bilateral lesions targeting lateral deep cerebellar nuclei, rats were subjected to a bridge test as a measure of visuomotor coordination and were trained on the Morris water maze (MWM) as a measure of visuospatial processing. Lesioned rats were significantly impaired in visuospatial processing, but not visuomotor coordination, relative to sham rats. In a 2nd experiment, rats were pretrained on a delayed spatial alternation task (T maze) before MWM training. Pretraining reversed the visuospatial deficit caused by the lesions as compared with nonpretrained rats. Results suggest that lateral deep cerebellar nuclei contribute to visuospatial processing with a negligible contribution to visuomotor skills and that visuospatial deficits resulting from lateral nuclei damage can be reversed with pretraining on aspatial working memory task.

Effects of hemolysis on serum chemistry analytes in ratites

Since hemolysis has been a common problem in submitted ratite serum samples, a study was performed to determine interference by hemolysates. Nine chemistry analytes including glucose, total protein, albumin, creatine kinase (CK), gamma-glutamyl transferase (GGT), aspartate aminotransferase (AS7), calcium (Ca), phosphorus, and uric acid were evaluated on a wet reagent analyzer (Ciba Corning Express 550) and on a dry slide reagent analyzer (VetTest 8008). In emus, increasing hemoglobin concentrations increased total protein, albumin, and CK for both analyzers. With increasing hemoglobin concentrations, the Ciba Corning 550 analyte values were increased for AST, Ca, and uric acid and decreased for glucose and phosphorus, the opposite effect was seen in values from the VetTest 8008. GGT levels were variable or sometimes undetectable. Changes in ostrich analytes with hemolysis were similar to emus using the same analyzer. The effects of serum hemolysis often differed in magnitude and direction between the two chemistry analyzers. Interferographs were constructed to aid in rapid assessment of the effects of hemolysis on submitted serum samples.

A comparison of spectrophotometry and color charts for evaluating total plasma carotenoids in wild birds

The study of the role of carotenoids on the physiology and evolutionary ecology of birds demands methods for their quantification in the bloodstream. We compared color-chart scores of plasma hue with the actual concentration of plasma carotenoids obtained by spectrophotometry in 356 wild birds from 26 species. Repeatability of chart scores between three independent observers was high. However, color scores did not correlate with the spectrophotometric results in interspecific analyses. Within species (n = 3), one showed no relationship and two showed weak but significant positive correlations. Hemoglobin, and probably other substances, may mask the color of carotenoids, making the accurate use of color charts difficult. Spectrophotometry should be the method of choice as it permits precise quantifications of total plasma carotenoids and objective comparisons among studies.