Evaluation and establishment of reference intervals using the i-STAT1 blood chemistry analyzer in turkeys

In veterinary medicine, point-of-care testing techniques have become popular, since they provide immediate results and only small amounts of blood are needed. The handheld i-STAT1 blood analyzer is used by poultry researchers and veterinarians; however, no studies have evaluated the accuracy of this analyzer determined reference intervals in turkey blood. The objectives of this study were to 1) investigate the effect of storage time on turkey blood analytes, 2) compare the results obtained by the i-STAT1 analyzer to those obtained by the GEM Premier 3000, a conventional laboratory analyzer, and 3) establish reference intervals for blood gases and chemistry analytes in growing turkeys using the i-Stat. For the first and second objectives, we used the CG8+ i-STAT1 cartridges to test blood from 30 healthy turkeys in triplicate and once with the conventional analyzer. To establish the reference intervals, we tested a total 330 blood samples from healthy turkeys from 6 independent flocks during a 3-yr period. Blood samples were then divided into brooder (<1 wk) and growing (1-12 wk of age). Friedman's test demonstrated significant time-dependent changes in blood gas analytes, but not for electrolytes. Bland-Altman analysis revealed that there was agreement between the i-STAT1 and the GEM Premier 300 for most of the analytes. However, Passing-Bablok regression analysis identified constant and proportional biases in the measurement of multiple analytes. Tukey's test revealed significant differences in the whole blood analytes between the means of brooding and growing birds. The data presented in the present study provide a basis for measuring and interpreting blood analytes in the brooding and growing stages of the turkey lifecycle, offering a new approach to health monitoring in growing turkeys.

The influence on behavior and physiology of white-feathered end-of-cycle hens during simulated transport

Transportation is a stressful procedure that can alter end-of-cycle hen (EOCH) behavior and physiology. This study (5 × 3 × 2 factorial arrangement) aimed to assess the effects of temperature (T)/relative humidity (RH) (-10°C uncontrolled RH (-10), +21°C 30%RH (21/30), +21°C 80%RH (21/80), +30°C 30%RH (30/30), +30°C 80%RH (30/80)), duration (4, 8, 12 h), and feather cover [well (WF) and poorly-feathered (PF)] on white-feathered EOCH (65-70 wk) behavior and physiology. EOCH (n = 630) from 3 commercial farms were housed for adaptation (3-5 d), fasted (6 h), crated (53 kg/m2), and placed in a climate-controlled chamber. Data collected included chamber and crate conditions, feather condition score, mortality, core body temperature (CBT), behavior, and delta (∆) blood physiology. Analyses were conducted via ANOVA in a randomized complete block design (farm of origin) with significance declared at P ≤ 0.05. PF EOCH had higher mortality than WF hens during cold exposure (-10). EOCH ∆CBT demonstrated a greater (positive) change at 12 h for all T/RH compared to 4 h at 21/30, 21/80, and -10 (negative). Cold exposure (-10) resulted in a higher percentage of time spent shivering and motionless, while heat exposure resulted in a higher percentage of time spent panting for WF EOCH exposed to 30/30 and WF and PF hens exposed to 30/80. Hen ∆glucose had a greater (negative) change at 4 and 12 h for -10 compared to 4 h at 21/30, and all durations for 21/80, 30/30, and 30/80. PF hens exposed to -10 had a greater (positive) change in ∆sodium, ∆hemoglobin, and ∆hematocrit compared to WF birds (negative). The development of metabolic alkalosis was supported by the increase in ∆blood pH over time and the increase in ∆partial pressure of carbon dioxide, ∆bicarbonate, and ∆base excess extracellular fluid during cold exposure (-10). These results indicated that EOCH exposed to heat endured thermal stress while PF hens exposed to cold were unable to cope with cold stress.

Whole blood gas and biochemical reference intervals for Lohmann Silver layers

The blood gas and biochemical reference range established with i-STAT clinical analyzer in avian has become common, however, the reference value for various laying hen lines is limited. Therefore, blood gas and biochemical reference intervals will be established for Lohmann Silver layers in the pre- and post-laying periods. The blood sample was collected at a 4-wk interval. A total of 230 Lohmann Silver layers including 80 pullets (5–17 wk) and 150 laying hens (21–37 wk) were collected for whole blood measurement with the i-STAT clinical analyzer. The CG8+ cartridge provides values of the following 13 parameters: sodium (Na mmol/L), potassium (K mmol/L), ionized calcium (iCa mmol/L), glucose (Glu mg/dL), hematocrit (Hct% Packed Cell Volume [PCV]), pH, partial pressure carbon dioxide (PCO₂ mm Hg), partial pressure oxygen (PO₂ mm Hg), total concentration carbon dioxide (TCO₂ mmol/L), bicarbonate (HCO₃ mmol/L), base excess (BE mmol/L), oxygen saturation (sO₂%), and hemoglobin (Hb g/dL). The correlation of these parameters and the effect of physiological status were investigated. The reference value interval was established with a reference value advisor for pre-laying and post-laying birds. Correlations were found to be statistically significant, especially between BE and HCO₃ and TCO₂. Besides, values in Na, iCa, K, Hct, Hb, sO₂ differed significantly between the pre- and post-laying periods. Data in this study might serve as important information for facilitating the genetic selection and assessing the health of Lohmann Silver laying hens.

Comparison of portable and conventional laboratory analyzers for biochemical tests in chickens

Antemortem blood biochemical and blood gas analyses are routinely used in health screening and diagnosis of disease in domestic veterinary species. These testing modalities are not routinely performed in poultry, in part, due to the distance from the diagnostic laboratory. Portable blood analyzers such as the i-STAT and VetScan (VS2) can be used to obtain results on the farm without delay, potentially offering a more practical option for poultry practitioners. We investigated the time effect on blood chemistry values and compared the results obtained using the i-STAT and VS2 with those obtained using conventional laboratory analyzers (GEM Premier 3000 and Cobas c501, respectively). We tested blood from 60 healthy chickens. Each sample was tested in triplicate using each of the portable analyzers and once using conventional analyzers. All samples were analyzed within 60 minutes of collection. The concentrations of some analytes were outside the limit of detection of the portable analyzers (i.e., bile acids). Although statistically significant differences were found for some biochemical analytes over time, the actual mean or median differences were too small to be considered of clinical importance. As observed in mammals, significant time-dependent changes in blood gas analytes were observed in whole blood samples exposed to ambient air. Correlation coefficients between portable and conventional analyzers were moderate to high for most of the analytes. For the most part, there was an agreement between the portable and conventional analyzers. We identified constant and proportional biases in the measurement of multiple analytes by both the i-STAT and VS2. Future studies are warranted to establish analyzer-specific reference intervals for poultry.

Research Note: Comparison of chicken blood chemistry and electrolyte parameters between the portable i-STAT1 clinical analyzer and VetScan VS2 serum biochemistry panel using Hy-Line commercial white-egg laying hens

The i-STAT1 clinical analyzer has become an increasingly popular tool in clinical production animal medicine as it can provide pen-side results in a cost effective and timely manner when compared to standard benchtop serum biochemistry blood gas and chemistry analyses. This study compares the results of the portable Abbott i-STAT1 analyzer and the Abaxis VetScan VS2 for glucose (Glu, mg/dL), ionized Ca (mmol/L), Na (mmol/L), and K (mmol/L) values. Three genetically distinct commercial varieties (CV) of Hy-Line white-egg laying hens are used in this study (Hy-Line W-36, Hy-Line W-80, and Hy-Line W-80+). Thirty blood samples (n = 10 per CV) were obtained in the production house from the brachial vein and concurrently analyzed by the i-STAT1 portable device. Serum from 22 of these same samples was analyzed via VetScan VS2, a benchtop serum clinical biochemistry analyzer, using VetScan Avian/Reptilian Profile Plus reagent rotors. A paired T-test was used to test for statistical differences in means between the 2 instruments for each of the parameters. Parameters with significant mean differences were then subject to correlation and regression analysis to further evaluate relationships between the results from the 2 methods. Significant differences between means were found for Glu, Na, and K levels. Ca levels were found to be not directly comparable by the 2 analysis instruments. This comparison elucidates the importance of clinical analyzer validations when applying different strategies of diagnostic medicine in poultry.