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

backgroundSubclinical ketosis (SCK) causes economic losses in the dairy industry because it reduces the milk production and reproductive performance of cows. HYPOTHESIS/

objectivesTo 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).

methodsThe 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

resultsThe 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.