Effects of sex, age, and season on the variation of blood analytes in a clinically healthy <i>ex situ</i> population of bottlenose dolphins (<i>Tursiops</i> spp.)

A comprehensive evaluation of the effects of sex, age, and season on blood analytes in a robust population size of <i>ex situ</i> bottlenose dolphins (<i>Tursiops</i> spp.) has not been investigated to date. To define the variation in hematological and biochemical analytes of dolphins due to sex, age, and season. 1,426 blood samples collected from 156 clinically normal dolphins consisting of 59 males and 97 females in which 37 analytes were measured were retrospectively identified. The dolphins were categorized by age, sex, and season, and categories were compared. About 23 (64%) analytes differed by age. The number of differences between adjacent age groups decreased with advancing age. MPV, glucose, BUN, globulins, GGT and Cl progressively increased with age, whereas Abs lymphs, total protein, ALP, CK and Ca progressively decreased with age. Three (8%) of analytes differed between sex, whereas 16 (44%) analytes differed by season. Female dolphins had higher median iron (33 µmol/L) than male dolphins (25 µmol/L). Female dolphins also had higher Abs lymphs and MCHC, but Abs lymphs and MCHC also differed between age and season, respectively. Sex inconsistently and relatively infrequently influences analytes. Delphinids of advancing age experience immune senescence and decreasing renal perfusion or clearance. These results demonstrate the importance of considering the influences of sex, age, and season on blood data, provide a baseline for accurate interpretation of clinicopathological analytes of delphinids in managed care, and will be useful for investigations into health, disease, and stressors of wild delphinids.迄今为止，针对种群规模可观的迁地（ex situ）宽吻海豚属（Tursiops spp.）群体，开展性别、年龄与季节对血液分析物影响的全面评估尚未见报道。本研究旨在明确性别、年龄及季节因素对海豚血液学与生化分析物水平的影响。本研究回顾性筛选了156头临床健康宽吻海豚的1426份血液样本，其中雄性59头、雌性97头，共检测了37项血液分析物。研究按年龄、性别与季节对海豚进行分组，并对各组进行比较分析。约23项（64%）血液分析物的水平存在年龄相关差异。相邻年龄组间的分析物差异数量随年龄增长逐渐减少。平均血小板体积（MPV）、葡萄糖（glucose）、血尿素氮（BUN）、球蛋白（globulins）、γ-谷氨酰转移酶（GGT）及氯离子（Cl）随年龄增长呈进行性升高，而淋巴细胞绝对值（Abs lymphs）、总蛋白（total protein）、碱性磷酸酶（ALP）、肌酸激酶（CK）及钙离子（Ca）随年龄增长呈进行性降低。3项（8%）分析物存在性别相关差异，16项（44%）分析物存在季节相关差异。雌性海豚的血清铁中位数为33 μmol/L，高于雄性海豚的25 μmol/L。雌性海豚的淋巴细胞绝对值与平均红细胞血红蛋白浓度（MCHC）也更高，但淋巴细胞绝对值与平均红细胞血红蛋白浓度分别存在年龄与季节相关差异。性别对血液分析物的影响并不稳定，且相对少见。年龄较大的海豚科动物会出现免疫衰老以及肾脏灌注或清除功能下降。本研究结果证实了在分析血液数据时需考虑性别、年龄与季节因素影响的重要性，为人工管护环境下海豚科动物临床病理分析物的精准解读提供了参考基线，同时可为野生海豚科动物的健康、疾病及应激源相关研究提供支持。