Evaluation of two devices for point-of-care testing of haemoglobin in neonatal pigs

Preliminary research on tailored fluid therapy in pigs: comparing customized ionic solutions with Hartmann's solution

BACKGROUND

Fluid therapy in veterinary medicine is pivotal for treating various conditions in pigs; however, standard solutions, such as Hartmann's solution, may not optimally align with pig physiology. This study explored the development and efficacy of a customized fluid therapy tailored to the ionic concentrations of pig blood, aiming to enhance treatment outcomes and safety in both healthy and diseased pigs.

RESULTS

The study involved two experiments: the first to assess the safety and stability of customized fluids in healthy pigs, and the second to evaluate the efficacy in pigs with clinical symptoms of dehydration. In healthy pigs, the administration of customized fluids showed no adverse effects, with slight alterations observed in pO2, hematocrit, and glucose levels in some groups. In symptomatic pigs, the customized fluid group did not show any improvement in clinical symptoms, with no significant changes in blood chemistry or metabolite levels compared to controls. The customized fluid group showed a mild increase in some values after administration, yet within normal physiological ranges. The study reported no significant improvements in clinical or dehydration status, attributing the observed variations in blood test results to the limited sample size and anaesthesia effects rather than fluid characteristics.

CONCLUSIONS

Customized fluid therapy, tailored to mimic the ionic concentrations of pig blood, appears to be a safe and potentially more effective alternative to conventional solutions such as Hartmann's solution for treating pigs under various health conditions. Further research with larger sample sizes and controlled conditions is recommended to validate these findings and to explore the full potential of customized fluid therapy in veterinary practice.

Iron status in piglets at three days of age and at weaning and possible seasonal effects on the blood haemoglobin levels in a Swedish outdoor pig-producing farm

BACKGROUND

Piglets are born with limited stores of iron, and with an increasing number of live-born piglets, there may be a risk that the sows cannot provide enough iron to their offspring. The iron content in soil may not meet the demands of today's piglet, born and reared in an outdoor setting. The study aimed to describe the blood haemoglobin (Hb) levels in pigs reared outdoors and to determine whether piglets have higher Hb levels at weaning when an iron supplement is administered intramuscularly at three days of age, as compared to pigs not given an iron supplement. The seasonal variation in Hb-levels was also to be investigated. The Hb concentration was analysed with a HemoCue 201 + Hb photometer.

RESULTS

In total 56 litters (399 piglets) were included in the study and sampled at three days of age, while 378 piglets were sampled at weaning. The mean Hb level at three days of age was 91 g/L (48-154 g/L). In total 47% of the piglets had Hb levels < 90 g/L at three days of age. The mean Hb level at weaning was 127 g/L (76-176 g/L), with a lower level (122 g/L) in the group given the iron supplement than in the group not given an iron supplement (132 g/L). Only 1% of the piglets had Hb levels lower than 90 g/L at weaning. Results indicative of a seasonal effect on Hb levels at three days of age was demonstrated. Piglets born in spring had significantly lower Hb levels, and piglets born in autumn had significantly higher Hb levels. No seasonal effect could be demonstrated for Hb levels at day 33.

CONCLUSIONS

The results indicate that the natural uptake from the environment was sufficient, but that there was a seasonal effect on the Hb levels at three days of age. This indicates that there might be a need for different routines regarding iron supplementation in outdoor reared piglets depending on the climate and season.

Effects of a second iron-dextran injection administered to piglets during lactation on differential gene expression in liver and duodenum at weaning

Six female littermate piglets were used in an experiment to evaluate the mRNA expression in tissues from piglets given one or two 1 mL injections of iron dextran (200 mg Fe/mL). All piglets in the litter were administered the first 1 mL injection < 24 h after birth. On day 7, piglets were paired by weight (mean body weight = 1.72 ± 0.13 kg) and one piglet from each pair was randomly selected as control (CON) and the other received a second injection (+Fe). At weaning on day 22, each piglet was anesthetized, and samples of liver and duodenum were taken from the anesthetized piglets and preserved until mRNA extraction. differential gene expression data were analyzed with a fold change cutoff (FC) of |1.2| P < 0.05. Pathway analysis was conducted with Z-score cutoff of P < 0.05. In the duodenum 435 genes were significantly changed with a FC ≥ |1.2| P < 0.05. In the duodenum, Claudin 1 and Claudin 2 were inversely affected by + Fe. Claudin 1 (CLDN1) plays a key role in cell-to-cell adhesion in the epithelial cell sheets and was upregulated (FC = 4.48, P = 0.0423). Claudin 2 (CLDN2) is expressed in cation leaky epithelia, especially during disease or inflammation and was downregulated (FC = -1.41, P = 0.0097). In the liver, 362 genes were expressed with a FC ≥ |1.2| P < 0.05. The gene most affected by a second dose of 200 mg Fe was hepcidin antimicrobial peptide (HAMP) with a FC of 40.8. HAMP is a liver-produced hormone that is the main circulating regulator of Fe absorption and distribution across tissues. It also controls the major flows of Fe into plasma by promoting endocytosis and degradation of ferroportin (SLC4A1). This leads to the retention of Fe in Fe-exporting cells and decreased flow of Fe into plasma. Gene expression related to metabolic pathway changes in the duodenum and liver provides evidence for the improved feed conversion and growth rates in piglets given two iron injections preweaning with contemporary pigs in a companion study. In the duodenum, there is a downregulation of gene clusters associated with gluconeogenesis (P < 0.05). Concurrently, there was a decrease in the mRNA expression of genes for enzymes required for urea production in the liver (P < 0.05). These observations suggest that there may be less need for gluconeogenesis, and possibly less urea production from deaminated amino acids. The genomic and pathway analyses provided empirical evidence linking gene expression with phenotypic observations of piglet health and growth improvements.

A second iron injection administered to piglets during lactation improves hemoglobin concentration, growth performance, and carcass characteristics at slaughter

An experiment was conducted to evaluate the effects of a second injection of iron dextran administered on days 6 to 8 of age. A total of 144 crossbred pigs (equal barrows and gilts; initial age 6 to 8 d; initial body weight [BW] = 2.86 ± 0.01 kg) were assigned to either the control (CON) or an added-injection treatment (+Fe). Pigs were paired by sex and BW within a litter and randomly assigned to the iron treatment within each pair. All pigs had received an initial intramuscular (IM) injection of iron dextran (200 mg Fe) <24 h after birth. Pigs assigned to the +Fe treatment received a second IM injection of iron dextran (200 mg Fe) on days 6 to 8. All pigs were weaned at 22 to 25 d, housed 6 pigs/pen, and received a common corn-soybean meal diet. BW and feed disappearance were recorded every 2 wk. Hemoglobin (Hb) concentrations were measured at birth, initiation of experiment (days 6 to 8), weaning, and the end of the nursery and end of the study. At the end of the study, 1 pig/pen (n = 12 pigs/treatment), closest to the pen mean was selected and slaughtered for carcass characteristic measures. The individual pig served as the experimental unit for BW, Hb, average daily gain (ADG), and carcass characteristic data whereas the pen served as the experimental unit for average daily feed intake, and gain/feed ratio data. The +Fe pigs had a greater Hb at weaning (13.1 vs. 10.7 g/dL, respectively; P < 0.01) and end of the nursery (12.1 vs. 11.7 g/dL, respectively; P = 0.01) compared to CON pigs. During the finisher period, +Fe pigs had a greater ADG (0.94 vs. 0.91 kg, respectively; P = 0.05) compared to CON pigs. Overall, pigs receiving the second iron injection had an ~4% increase in ADG (P = 0.04) from weaning to the end of study. The cumulative improvement in ADG from weaning to the end of study observed for +Fe group resulted in +Fe pigs having a heavier BW at the end of the study (~3 kg; P = 0.04). Following slaughter, +Fe pigs had ~7.2% heavier trimmed loin (P = 0.04) compared to the CON pigs. In conclusion, administering a second iron injection resulted in greater Hb at weaning and the end of the nursery as well as improved growth performance from weaning to the end of study weight and increased carcass weight at slaughter.

Effects of two alveolar recruitment manoeuvres (sustained inflation and stepwise) followed by positive end-expiratory pressure on cardiac output (measured with lithium dilution), invasive blood pressure and arterial oxygen tension in isoflurane-anaesthetised goats

Alveolar recruitment manoeuvres (ARM) performed during general anaesthesia improve oxygenation; however cardiovascular depression may be observed. The aim of the study was to compare the effects of sustained inflation (SI) and stepwise ARMs on cardiac output (CO), mean arterial blood pressure and arterial oxygen tension (PaO2) in ten mechanically ventilated goats anaesthetised with isoflurane. In the SI ARM, peak inspiratory presure (PIP) was increased to 30 cmH2O and sustained for 20 s. In the stepwise ARM, the PIP was increased by 5 cmH2O each minute for three minutes from 10 to 25 cmH2O. Both ARMs were followed by positive end-expiratory pressure of 5 cmH2O. Paired lithium dilution CO measurements and arterial blood samples were obtained before and after each ARM. The order of the ARM was randomised and each goat was subjected to both techniques. Data was reported as median and interquartile range (IQR). Significance was set at 0.05. The median change in CO (measured by subtracting values after and before ARM) was -0.15 L min-1 (IQR -0.51; 0.03) and - 0.90 L min-1 (IQR -1.69; -0.58) for SI and stepwise ARM respectively (p = 0.04). The median change in PaO2 was 3 kPa (IQR -2.7; 7.6) and 0.4 kPa (IQR -3.4; 5.5) for SI and stepwise ARM respectively (p = 0.03). In conclusion, SI ARM causes less impact on CO and provides a better improvement in PaO2 compared to stepwise ARM in goats.

Lithium dilution cardiac output measurements in isoflurane-anaesthetised goats: Jugular versus cephalic lithium chloride administration

The administration of lithium chloride (LiCl) for cardiac output (CO) measurement via a peripheral instead of a central vein has been described previously as a valid alternative route in pigs and dogs. The aim of the study was to compare CO measurements after administration of LiCl using two peripheral veins, cephalic or jugular, in goats. Ten adult, female, experimental goats undergoing bilateral stifle arthrotomy were recruited for the study. Paired CO measurements were taken two minutes apart during stable conditions in isoflurane-anaesthetised goats. Forty-two paired CO measurements were taken in total, and the median (range) of paired CO measurement per goat were 4.5 (3-6). The mean (SD) CO using the cephalic and jugular vein for injection of LiCl was 5.28 (1.29) L min^-1 and 5.20 (1.24) L min^-1 respectively. The Bland-Altman analysis showed an acceptable agreement with a mean bias of 1.33% with limits of agreement (LoA) of -18.43 to 21.09%. The percentage of error was 25%. The four-quadrant plot analysis showed a poor agreement (71%) between the two routes. The polar plot showed a poor trending ability. An 86% inclusion rate (18/21 points) was reached with a ± 35° radial sector size. The findings revealed that the agreement between the two routes is not as precise as the authors expected, however the results are comparable with studies published previously.

Engineering a simple lateral flow device for animal blood coagulation monitoring

Increasing numbers of animals are diagnosed with thromboembolism, requiring anticoagulation treatment to prevent thrombotic events. Frequent and periodic coagulation monitoring is critical to ensure treatment effectiveness and patient safety by limiting blood coagulation ability within the desired therapeutic range. Point-of-care diagnostics is an ideal candidate for frequent coagulation monitoring due to rapid test results and no need for laboratory setting. This article reports the first utilization of no-reaction lateral flow assay (nrLFA) device for simple and low-cost animal blood coagulation monitoring in resource-limited setting. The nrLFA device consists of sample pad, analytical membrane and wicking pad, without conjugate pad, reagent printing or membrane drying. Citrated and heparinized animal blood were utilized to mimic different blood coagulation abilities in vitro by adding reversal agents CaCl2 and protamine sulfate. The travel distance of red blood cells (RBCs) on the nrLFA after a pre-determined test time serves as endpoint marker. Upon adding 500 mM CaCl2 solution to citrated bovine, canine, rabbit and equine blood, the average travel distance decreases from 10.9 to 9.4 mm, 8.8 to 5.7 mm, 12.6 to 9 mm, and 15.3 to 11.3 mm, respectively. For heparinized bovine and rabbit blood, the average distance decreases from 14.5 to 11.4 mm and from 9.8 to 7.2 mm, respectively, when adding 300 mg/l protamine sulfate solution. The effect of hematocrit on RBC travel distance in the nrLFA was also investigated. The nrLFA device will potentially improve treatment efficiency, patient safety, quality of life, and satisfaction for both animal patients and their owners.

Blood parameters as biomarkers in a Salmonella spp. disease model of weaning piglets

BACKGROUND

The weaning pig is used as an experimental model to assess the impact of diet on intestinal health. Blood parameters (BP) are considered a useful tool in humans, but there is very scarce information of such indicators in the weaning pig. The objective of the present study is to evaluate the use of different BP as indicators in an experimental model of salmonellosis.

METHODOLOGY

Seventy-two 28-day-old piglets were divided into four groups in a 2x2 factorial arrangement, with animals receiving or not a probiotic combination based on B. infantis IM1® and B. lactis BPL6 (109 colony forming units (cfu)/d) and orally challenged or not a week later with Salmonella Typhimurium (5x108 cfu). Blood samples of one animal per pen (N = 24) were taken four days post-inoculation for the evaluation of different BP using an I-stat® System and of plasmatic concentrations of zinc, iron and copper.

PRINCIPAL FINDINGS

Results reported marginal deficiencies of zinc in piglets at weaning. Moreover, plasmatic zinc, copper and iron presented good correlations with weight gain (r 0.57, r -0.67, r 0.54 respectively; P < 0.01). Blood electrolytes (Na+, Cl- and K+) decreased (P < 0.01) only when the performance of the animals was seriously compromised and clinical symptoms were more apparent. Acid-base balance parameters such as HCO3-, TCO2 and BEecf significantly correlated with weight gain, but only in the challenged animals (r -0.54, r -0.55, and r -0.51, respectively; P < 0.05), suggesting metabolic acidosis depending on Salmonella infection. Glucose was affected by the challenge (P = 0.040), while Htc and Hgb increased with the challenge and decreased with the probiotic (P < 0.05). Furthermore, correlations of Glu, Htc and Hgb with weight gain were observed (P < 0.05). Overall, BP could be regarded as simple, useful indexes to assess performance and health of weaning piglets.

Calibration of the HemoCue point-of-care analyser for determining haemoglobin concentration in a lizard and a fish

Haemoglobin concentration ([Hb]) is measured for a wide variety of animal studies. The use of point-of-care devices, such as the HemoCue, is becoming increasingly common because of their portability, relative ease of use and low cost. In this study, we aimed to determine whether the [Hb] of blue-tongued skink (Tiliqua nigrolutea) blood can be determined accurately using the HemoCue and whether the HemoCue overestimates the [Hb] of reptile blood in a similar manner to fish blood. Additionally, we aimed to test whether ploidy affected [Hb] determined by the HemoCue using blood from diploid and triploid Atlantic salmon (Salmo salar). The HemoCue Hb 201(+) systematically overestimated [Hb] in both blue-tongued skinks and Atlantic salmon, and there was no difference between calibration equations determined for diploid or triploid salmon. The overestimation was systematic in both species and, as such, [Hb] determined by the HemoCue can be corrected using appropriate calibration equations.