Abstract
Background & Aims:
Gastrointestinal nematodes are common in poultry, particularly in small-scale and traditional production systems where birds are frequently exposed to contaminated environments. These infections have been associated with reduced productivity and growth performance; however, their impact on the biochemical composition of skeletal muscle remains poorly understood. This study examined the association between naturally acquired gastrointestinal nematode infection and changes in skeletal muscle biochemical composition in chickens (Gallus gallus).
Methods:
Between March and May 2025, twenty-five chickens intended for human consumption were examined in the Zulfi region, Saudi Arabia. The gastrointestinal tract of each bird was evaluated for helminth infection. Six birds were naturally infected, and nematodes were morphologically identified as Ascaridia spp. Skeletal muscle samples from infected (n = 6) and uninfected (n = 6) chickens were analyzed. Standard colorimetric assays were used to determine lipid, carbohydrate, and protein concentrations, followed by statistical analysis.
Results:
Compared with controls, infected chickens showed significantly lower muscle lipid and carbohydrate levels (P ≤ 0.05). Protein levels were also lower in infected birds; however, the difference was not statistically significant.
Conclusion:
These findings suggest that naturally acquired gastrointestinal nematode infection may be associated with measurable alterations in skeletal muscle biochemical composition under field conditions. Such changes may influence the nutritional quality of poultry meat. Further controlled studies are required to confirm these findings and clarify the underlying mechanisms.

Key words: Gallus gallus; gastrointestinal nematodes; skeletal muscle; biochemical composition