Correlation analysis of anthropometric parameters and macromorphology of intestinal lymphoid tissue in female lynx (Lynx lynx) juveniles

Purpose: to study the relationship between morphometric parameters of intestinal lymphoid tissue and anthropometric indicators (weight, body length) in young female Eurasian lynx (Lynx lynx).

Materials and Methods. The analysis included data from 12 individuals harvested during legal hunting and scientific shooting in 2023–2024 in the Kirov Region and adjacent regions. To study the intestinal morphometry of lymphoid tissue, small and large intestinal samples were used, in which the number, size, and spatial distribution of lymphoid nodules and plaques were measured. Anthropometric parameters (body weight accurate to the nearest 5 g, body length) were recorded before butchering.

The study results revealed a number of significant patterns. First, a general biological relationship between body weight and body length was confirmed (ρ=0,800, p=0,002). Secondly, a strong correlation was found between the duodenum area and body weight (ρ=1.000, p<0.01). However, negative correlations were also revealed: body weight was associated with a decrease in the number of lymphoid nodules in the duodenum (ρ=-0,800, p=0,002), while body length was associated with a decrease in the area of ​​the ileum (ρ=-0,800, p=0,002). Age-related dynamics of lymphoid structures in lynxes is manifested in a decrease in the number of nodules (ρ=-0,800) and plaques (ρ=-0,775) in the duodenum against the background of an increase in the distance between them (ρ=0,800). The species-specific characteristics of the lynx are reflected in the spatial distribution of lymphoid structures: in the jejunum, a positive correlation was found between the area of ​​nodules (ρ=0,800) and the number of plaques (ρ=0,632) and metabolic activity, which is characteristic of adaptation to an antigen load in the wild. Morphometric analysis revealed a structural reorganization of the lymphoid tissue: a decrease in the distance between nodules (ρ=-0.600) with a simultaneous increase in their number (ρ=0,600), indicating compaction and optimization of the spatial arrangement of immune structures. The predominance of lymphoid plaques in the duodenum (ρ=0,949, p<0,001) is similar to data for canids, in which they constitute up to 70 % of the lymphoid mass of the proximal sections.

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