Comparative Analysis of Morphology and Targeted Fatty Acid Profiling of Adipose Tissues from Different Depots in the Junggar Bactrian Camel

Adipose tissue exhibits profound anatomical heterogeneity that underpins distinct physiological roles, yet depot-specific morphological and metabolic differentiation in camelids remains elusive. Here, we systematically characterized hump adipose tissue (HAT), mesenteric adipose tissue (MAT), pericardial adipose tissue (PAT), and perirenal adipose tissue (PRAT) from 13 adult male Junggar Bactrian camels using H&E histomorphometry and GC-MS-based targeted fatty acid profiling. Morphologically, PRAT displayed significantly larger mean adipocyte equivalent diameter and cross-sectional area than HAT and MAT (p < 0.05); conversely, MAT exhibited the highest adipocyte density, whereas HAT featured smaller, uniformly sized cells with densely packed lipid droplets. Targeted fatty acid profiling revealed that HAT contained markedly elevated monounsaturated fatty acids—particularly palmitoleic acid (C16:1 n-7) and oleic acid (C18:1 n-9)—constituting 34.60% ± 2.82% of total fatty acids compared to 28.32% ± 1.23% in visceral depots (p < 0.01). In contrast, visceral fats (MAT, PRAT, PAT) were dominated by saturated fatty acids, with MAT exhibiting the highest stearic acid (C18:0) content. Principal component analysis and partial least squares discriminant analysis (PLS-DA) revealed marked metabolic differentiation of HAT from other depots, while PAT and PRAT shared highly similar profiles. Differentially abundant metabolites were predominantly enriched in fatty acid biosynthesis and unsaturated fatty acid biosynthesis pathways. These findings reveal distinct depot-associated differences in adipocyte morphology and fatty acid composition. The unique phenotypic profile of HAT is consistent with a putative role in lipid storage, potentially reflecting an adaptation to arid environments, while visceral depots exhibited traits conducive to biomechanical cushioning and metabolic regulation. This work describes depot-associated differences in adipocyte morphology and fatty acid composition in the Junggar Bactrian camel, supporting the potential for valorizing unique camel fat resources.