Effects of rare earth-chitosan chelate on liver and kidney parameters in lactating dairy cows

Abstract Text: Rare earth-chitosan chelate (RECC) formed by β-NH₂ and rare earth ions with glucosamine molecule (1,4)-OH on the glycosidic bond, have been used as a new chelating ligand feed additives to promote efficient feed utilization in ruminants and improve animal productivity while reducing the need for antibiotics and chemical additives. Numerous reports have indicated that suitable amount of RECC mixtures in the diet increase not only the liveweight gain of livestock and poultry but also milk and egg production. The objective of this study was to determine the effect of different proportion of rare earth-chitosan chelate (RECC) on hepatic and renal function of lactating dairy cows. Forty-eight lactating Holstein dairy cows (DIM = 130 ± 5, average milk yield = 33.2 ± 5.1 kg/d) were randomly assigned to 4 treatments (n = 12) with addition of RECC (0 (control), 0.15%, 0.75%, and 1.5%, respectively) in diets. The experiment lasted for 9wk with the first week for adaptation. Blood was collected in evacuated tubes via caudal venipuncture at 0, 2, 4, 6, 8 week and the tubes with blood samples were centrifuged at 3,500 × g for 15 min to obtain serum, which was separated into several aliquots and stored at −80°C in an ultra-low-temperature freezer until further analysis. Data were analyzed by mixed or GLM procedure of SAS software. No significant differences (P > 0.05) were found for the activity of glutamic-pyruvic transaminase (ALT) and glutamic oxalacetic transaminase (AST), total protein (TP), albumin (ALB), globulin (GLB), Uric Acid (UA) and urea nitrogen(UREA) in all the dietary treatments. Compared with control, there were no difference (P > 0.05) in total bile acid (TBA) and creatinine (CRE) between 0.15% RECC and 0.75% RECC treatments, while increased (P < 0.05) when the RECC adding dose up to 1.5%. Feeding 0.15% or 1.5% RECC resulted in higher total bilirubin(TBIL)(5.77, 6.05 umol/L vs. 4.89, 4.89 umol/L) and indirect bilirubin (DBIL) (2.30, 2.54 umol/L vs. 2.00, 1.93 umol/L) vs. control and 0.75% RECC group (P < 0.01). These results suggested that the adding doses of RECC in dietary did not affect the activity of ALT and AST, while TBA, CRE, TBIL and DBIL were significantly increased in 0.15% RECC. So it was concluded that adding 1.5% RECC in dietary has a negative effect on the function of liver and kidney in dairy cows.

Keywords: dairy cows, liver and kidney parameters, rare earth-chitosan chelate