A study on variability of bioactive proteins in camel (Camelus dromedarius) milk: Insulin, insulin-like growth factors, lactoferrin, immunoglobulin G, peptidoglycan recognition protein-1, lysozyme and lactoperoxidase

Milk samples were collected from 140 individual dromedary camels (Camelus dromedarius) to determine the variability in the concentrations of several bioactive whey proteins. The ranges were as follows: insulin (IN) (17.8–51.1 mIU/L), insulin-like growth factor I (IGF1) (1.4–736.1 ng/mL), insulin-like growth factor II (IGF2) (13.7–82.6 ng/mL), lactoferrin (639.4–2094.9 µg/mL), immunoglobulin G (IgG) (7.3–17.9 mg/mL), peptidoglycan recognition protein-1 (PGRP-1) (1.6–22.3 ng/mL), lysozyme (LZ) (23.3–71.4 µg/mL) and lactoperoxidase (LPO) (7.1–15.5 ng/mL). These data demonstrate wide variation in the concentrations of the studied proteins. Significant correlations (P < 0.05) were observed between the concentrations of IN and LZ, IN and IgG, IN and PGRP-1, LZ and PGRP-1, IgG and LPO, and IgG and PGRP-1.