Haematological and blood biochemical characteristics of Glyptosternum maculatum (Siluriformes: Sisoridae) in Xizang (Tibet)

Genome and population evolution and environmental adaptation of Glyptosternon maculatum on the Qinghai-Tibet Plateau

Persistent uplift means the Qinghai-Tibet Plateau (QTP) is an ideal natural laboratory to investigate genome evolution and adaptation within highland environments. However, how paleogeographic and paleoclimatic events influence the genome and population of endemic fish species remains unclear. Glyptosternon maculatum is an ancient endemic fish found on the QTP and the only critically endangered species in the Sisoridae family. Here, we found that major transposons in the G. maculatum genome showed episodic bursts, consistent with contemporaneous geological and climatic events during the QTP formation. Notably, histone genes showed significant expansion in the G. maculatum genome, which may be mediated by long interspersed nuclear elements (LINE) repetitive element duplications. Population analysis showed that ancestral G. maculatum populations experienced two significant depressions 2.6 million years ago (Mya) and 10 000 years ago, exhibiting excellent synchronization with Quaternary glaciation and the Younger Dryas, respectively. Thus, we propose that paleogeography and paleoclimate were dominating driving forces for population dynamics in endemic fish on the QTP. Tectonic movements and temperature fluctuation likely destroyed the habitat and disrupted the drainage connectivity among populations. These factors may have caused severe bottlenecks and limited migration among ancestral G. maculatum populations, resulting in the low genetic diversity and endangered status of the species today.

Intestinal microbiome and its potential functions in bighead carp (Aristichthys nobilis) under different feeding strategies

Bighead carps (Aristichthys nobilis) were divided into four groups with different feeding strategies: group A, nature live food only (fertiliser only, 200 g urea + 160 g ethylamine phosphate + 250 g Huangjintai bio-fertiliser); group B, nature live food + 1/2 formulated feed; group C, nature live food + formulated feed; and group D, formulated feed only. The intestinal microbiomes of the different groups were compared through the Illumina MiSeq sequencing of the bacterial 16S rRNA gene. The specific growth rate (SGR), survival and blood biochemical factors of the fish were also investigated. Results showed that feeding treatment influenced the intestinal communities in the fish. In specific, more bacterial phyla dominated in groups A and B (phyla Bacteroidetes, Fusobacteria, Firmicutes and Proteobacteria in group A, phyla Proteobacteria and Fusobacteria in group B) than in groups C and D (phylum Proteobacteria). The diversity was also lower in groups C and D than in groups A and B. Unweighted pair-group method analysis revealed a clear difference in intestinal microbiota among the different feeding treatments. No difference in survival rate was found among the treatment groups, but the SGR was significantly higher (P < 0.01) in groups B, C and D than in group A. Functional analysis showed that the intestinal bacteria correlated with fish glucose metabolism in group A but with lipid metabolic activity in groups B, C and D. In summary, the intestinal microbiomes and their potential functions vary in bighead carp under different feeding treatments. This study provides new insights into the gut microbiomes of filter-feeding and formulated diet-fed fish.

Comparison of hematological parameters in two different high altitudinal populations of Batrachuperus pinchonii (Amphibian: Urodela)

Hematological parameters are key to reflect the health status of animals and their physiological adaptation to the environment. However, few studies focused on the inter- and intra-specific variations of hematological parameters in hynobiid salamanders. Here, we examined the hematological parameters of the stream salamander,Batrachuperus pinchonii, originating from two different altitudinal populations to explore their intra-specific variation. Sexual dimorphism is only present in the erythrocyte count and males have higher mean values than females. The morphometric values of erythrocyte, hemoglobin concentration, and erythrocyte count of the high altitudinal (Jiajin) population were smaller than those of the lower altitudinal (Sandaoping) population; however, a significant difference between two populations was only revealed in the case of erythrocyte length via ANOVA. The results of linear regression showed that a significant relationship was present between body condition and erythrocyte length as well as the erythrocyte length to erythrocyte width ratio. Our findings suggest that the features of hematological parameters inB. pinchoniiare reflected in the size of erythrocyte, and neither in erythrocyte count nor in hemoglobin concentration. These results provide a foundation for assessing and monitoring the health status of this salamander species, and furthermore, for understanding the physiological basis of altitudinal adaptation.

Hematologic and plasma chemistry RIs for cultured Striped catfish (Pangasius hypophthalmus) in recirculating aquaculture systems

BACKGROUND

Striped catfish (Pangasius hypophthalmus) is a valuable aquaculture fish species produced primarily in Southeast Asia. In the United States, it is bred as an ornamental species. Striped catfish has high productivity and great demand in numerous countries around the world, yet little is known about its normal physiology.

OBJECTIVES

The objective of this study was to establish hematologic and blood chemistry RIs for healthy juvenile Striped catfish.

METHODS

Blood samples were collected from 70 Striped catfish raised in recirculating aquaculture systems. Whole blood and plasma samples were analyzed for multiple hematologic and chemistry variables using standard techniques.

RESULTS

The RIs for hematology were as follows: PCV 23.5-35.9%, MCV 106.3-156.6 fL, RBC count 1.79-2.75 × 10⁶ cells/μL, thrombocytes 26,318-73,333 cells/μL, total WBC count 36,294-94,286 cells/μL, total lymphocytes 18,997-59,998 cells/μL, small lymphocytes 13,763-51,490 cells/μL, large lymphocytes 715-21,200 cells/μL, granulocytes 4504-18,291 cells/μL, and monocytes 0-7549 cells/μL. Plasma chemistry RIs were the following: ALP 32.7-74.6 U/L, AST 20.3-1235.8 U/L, sodium 135.2-147.7 mmol/L, potassium 3.3-5.0 mmol/L, chloride 120.1-133.6 mmol/L, calcium 2.7-3.6 mmol/L, magnesium 0.9-1.3 mmol/L, phosphorous 1.4-2.7 mmol/L, glucose 4.6-7.6 mmol/L, cholesterol 2.8-5.3 mmol/L, total protein 30-42 g/L, albumin 7-11 g/L, globulin 22-32 g/L, albumin:globulin ratio 0.27-0.37, creatinine 0-8 μmol/L, and osmolality 251.8-327.9 mOsm/kg.

CONCLUSIONS

Reference intervals reported here can help veterinarians and fish health specialists monitor the health status of Striped catfish under recirculating aquaculture conditions for research, exhibition, and production purposes.

Blood cells of a sisorid catfish Glyptosternum maculatum (Siluriformes: Sisoridae), in Tibetan Plateau

The peripheral blood cells of a sisorid catfish Glyptosternum maculatum were studied using light microscope and transmission electron microscope. The size of cells and nucleus, and the percentage of different leucocytes were also described. Erythrocytes and four types of leucocytes: lymphocytes, heterophils, monocytes, and thrombocytes were characterized in G. maculatum blood. The dividing erythrocytes could be found sporadically. A plasma cell was observed under a transmission electron microscope. The morphology and structure of blood cells of G. maculatum were basically similar to those of other fish species, although there were also main differences, such as larger erythrocytes than other catfishes, absence of basophils and acidophils, and various types of thrombocytes (five types: lone nucleus, fusiform, tadpole-like, oval, and in a cluster).