Intravaginal administration of probiotics modulated serum metabolites and milk composition of transition dairy cows

Abstract Text: Transition dairy cows experience great metabolic fluctuations due to dietary changes and calving-induced stress, which also influence milk composition. Therefore, the objective of this study was to evaluate metabolic responses of periparturient dairy cows administered intravaginally with probiotics around calving. One hundred pregnant Holstein cows were randomly (based on parity, BCS, and milk yield) assigned to 3 groups 2 wk before the expected day of parturition as following: 1) 1 dose of probiotic culture on wk -2 and -1 and 1 dose of carrier on wk +1 (TRT1); 2) 1 dose of probiotics on wk -2, -1, and +1 (TRT2), and 3) 1 dose of carrier on wk -2, -1, and +1 (CTR). Probiotics were a mixture of 3 lactic acid bacteria (LAB) composed of Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, and FUA3140, which were infused at 10⁸-10⁹ cfu per dose. Blood samples were collected from wk -2 to +3, and milk samples from wk +1 to +5 on a weekly basis. The concentration of serum metabolites and milk components were determined by spectrophotometry and data were analyzed with SAS 9.2 software. Concentrations of cholesterol in the serum were 108±4, 116±4, and 95±4 mg/dL (P < 0.01) in TRT1, TRT2, and CTR, respectively. Concentrations of lactate in the serum were 5.88±0.50, 4.85±0.39, and 3.52±0.35 mmol/L (P < 0.05) in TRT1, TRT2, and CTR, respectively. Cows in TRT2 had lower serum NEFA than CTR (452±64 vs. 631±59 µmol/L, P = 0.05) but greater BHBA (736±43 vs. 595±43 µmol/L, P < 0.05). Treatments had no effect on concentrations of glucose or insulin in the serum. In addition, TRT2 had the highest content of milk lactose (4.39±0.02%, 4.53±0.03%, and 4.44±0.03% in TRT1, TRT2, and CTR, respectively, P < 0.01), whereas TRT1 had the greatest content of milk protein (2.99±0.04, 2.93±0.05, and 2.82±0.05% in TRT1, TRT2, and CTR, respectively, P < 0.05). No differences were detected in the content of milk fat, total solid content, or SCC. In conclusion, data indicated that administration of probiotics in the vaginal tract of periparturient dairy cows modulated serum concentrations of selected metabolites related to carbohydrate and lipid metabolism as well as milk composition. More research is warranted to understand how intravaginally infused probiotics affect blood metabolites and milk composition.

Keywords: probiotics, serum metabolites, milk composition