Metabolic alterations in dairy cows with subclinical ketosis after treatment with carboxymethyl chitosan‐loaded, reduced glutathione nanoparticles

BACKGROUND: Subclinical ketosis (SCK) causes economic losses in the dairy industry because it reduces the milk production and reproductive performance of cows. HYPOTHESIS/OBJECTIVES: To evaluate whether carboxymethyl chitosan‐loaded reduced glutathione (CMC‐rGSH) nanoparticles can alleviate the incidence or degree of SCK in a herd. ANIMALS: Holstein dairy cows 21 days postpartum (n = 15). METHODS: The trial uses a prospective study. Five cows with serum β‐hydroxybutyric acid (BHBA) ≥1.20 mmol/L and aspartate aminotransferase (AST) <100 IU/L were assigned to group T1, 5 cows with BHBA ≥1.20 mmol/L and AST >100 IU/L to group T2, and 5 cows with BHBA <1.00 mmol/L and AST <100 IU/L to group C. Carboxymethyl chitosan‐loaded reduced glutathione (0.012 mg/kg body weight per cow) was administered to cows in T1 and T2 once daily via jugular vein for 6 days after diagnosis. Serum from all groups were collected 1 day before administration, then on days 1, 3, 5, 7, 10, and 15 after administration to determine the changes in biochemical index and (1)H‐NMR. RESULTS: The difference in liver function or energy metabolism indices in T1, T2, and C disappeared at day 7 and day 10 after the administration (P > .05). Valine, lactate, alanine, lysine, creatinine, glucose, tyrosine, phenylalanine, formate, and oxalacetic acid levels, and decrease in isoleucine, leucine, proline, acetate, trimethylamine N‐oxide, glycine, and BHBA levels were greater (P < .05) at day 7 than day 0 for cows in T2. CONCLUSIONS AND CLINICAL IMPORTANCE: Carboxymethyl chitosan‐loaded reduced glutathione treatment might alleviate SCK by enhancing gluconeogenesis and reducing ketogenesis in amino acids.