Hematology and Plasma Chemistry Reference Values in Nursehound Shark (Scyliorhinus Stellaris) Maintained Under Human Care

Serum chemistry, thyroxine concentration, and blood cell morphology of wild, young Blackchin Guitarfish Glaucostegus cemiculus sampled on the eastern Mediterranean coastline

OBJECTIVE

The Blackchin Guitarfish Glaucostegus cemiculus is endemic to the Mediterranean Sea and is critically endangered, but relevant routine laboratory data are unavailable. Our objectives were to determine the packed cell volume (PCV), comprehensive serum chemistry analytes, and serum total thyroxine (sTT4) concentration; compare serum albumin and serum globulin concentrations as measured by two different methods; and describe the blood cell morphology of healthy, free-ranging Blackchin Guitarfish.

METHODS

Wild Blackchin Guitarfish were captured using a seine net. Blood samples for serum chemistry and hematological analyses were obtained and measured using routine laboratory methods. The fish were tagged and released.

RESULT

This study included 43 Blackchin Guitarfish (17 males and 26 females) that were younger than 6 months as estimated based on total length and body weight. The median PCV (n = 23) was 22% (minimum-maximum [min-max] = 15-25%). Median sTT4 (n = 10) measured by chemiluminescence immunoassay was 7.86 nmol/L (min-max = 7.52-9.57 nmol/L). The study included a comprehensive, 25-analyte serum chemistry analysis (e.g., serum iron and unbound and total iron-binding capacity) and a morphological description of all blood cells. Serum electrophoresis (SEP; n = 13) yielded a consistent serum albumin-migrating protein fraction and four globulin fractions. Serum electrophoretograms corroborating these results are presented.

CONCLUSION

In Blackchin Guitarfish, the serum albumin-migrating fraction measured by SEP combined with serum total protein concentration yields a much higher albumin concentration compared to that measured by bromocresol green spectrophotometry. The true identity of this albumin-migrating fraction remains to be identified. The analytes' calculated 2.5-97.5% interpercentile intervals should be considered as reference intervals applying to Blackchin Guitarfish of similar age but should be applied cautiously to adult fish.

Hematological and plasma biochemical profile of two species of freshwater stingrays from the Amazon

The evaluation of hematological and plasma biochemical parameters and the subsequent establishment of reference intervals facilitate the diagnosis of the health status of animals. This work aimed to determine the blood parameters of wild specimens of the stingrays Potamotrygon motoro and Potamotrygon orbignyi from the lower Solimões River region, Amazonas, Brazil. One hundred forty-one stingrays were captured, 92 specimens of P. motoro and 49 of P. orbignyi, of both sexes and at different stages of development. No effect of sex was observed on the blood parameters of juvenile animals for both species. P. motoro neonates presented a distinct hematological and biochemical profile, with significantly lower hematocrit values, hemoglobina, number of erythrocytes, mean corpuscular hemoglobin concentration, monocytes, plasma glucose, total proteins, albumin, and globulin. On the other hand, total cholesterol and urea levels were significantly higher in this same group compared to juveniles of the same species. Comparison between species revealed lower values of triglycerides and total cholesterol in P. orbignyi of both sexes. The results obtained are pioneering for these Amazonian species in white water environments and will serve as a basis for evaluating the health status of wild stingrays. Thus, from the analysis of the blood of the P. motoro and P. orbignyi stingrays, it was possible to observe good health conditions.

Blood collection under anesthesia, peripheral blood cells, plasma biochemistry, and plasma protein electrophoresis in a living fossil: the Spotted Ratfish (Hydrolagus colliei)

This report describes the safe and effective handling under anesthesia, blood collection and main clinical pathology values determination for three adult Spotted Ratfish (Hydrolagus colliei) (two males and one female) successfully maintained under human care for more than 20 years. The anesthetic MS-222 diluted in tamponed salt water at 50 ppm provided deep narcosis with mean induction and recovery times of 5 and 20 min, allowing safe handling and blood collection in the three animals sampled. Major leukocyte types were similar to other teleost and elasmobranch species, identifying lymphocytes as the predominant leukocyte (75.5%), followed by the fine eosinophilic granulocytes (10.25%), the coarse eosinophilic granulocytes (9.75%), and a small percentage of monocytes (5.50%). Plasma biochemistry values in this species were like those seen in elasmobranchs, with the highest levels of blood urea nitrogen described in any Chondrichthyes (mean 679.7 mmol/l). Plasma protein electrophoresis analysis in the Spotted Ratfish showed five consistent fractions, like those previously described in other fish species, with a negligible quantity of proteins migrating in the region equivalent to albumin, and with fraction 4 (mean 53.20%) as the predominant fraction. Despite the limitations imposed by the small sample size and the challenging access to the studied species under human care, this study will shed light on and enhance clinical knowledge regarding Ratfish handling, anesthesia, blood collection, and analysis. It aims to deliver a comprehensive clinical pathology description, presenting valuable data for professionals engaged in the care and management of Chimaerans.