The effect of exogenous glucose infusion on early embryonic development in lactating dairy cows

Abstract

The objective of this study was to examine the effect of intravenous infusion of glucose on early embryonic development in lactating dairy cows. Nonpregnant, lactating dairy cows (n = 12) were enrolled in the study (276 ± 17 d in milk). On d 7 after a synchronized estrus, cows were randomly assigned to receive an intravenous infusion of either 750 g/d of exogenous glucose (GLUC; 78 mL/h of 40% glucose wt/vol) or saline (CTRL; 78 mL/h of 0.9% saline solution). The infusion period lasted 7 d and cows were confined to metabolism stalls for the duration of the study. Coincident with the commencement of the infusion on d 7 after estrus, 15 in vitro-produced grade 1 blastocysts were transferred into the uterine horn ipsilateral to the corpus luteum. All animals were slaughtered on d 14 to recover conceptuses, uterine fluid, and endometrial tissue. Glucose infusion increased circulating glucose concentrations (4.70 ± 0.12 vs. 4.15 ± 0.12 mmol/L) but did not affect milk production or dry matter intake. Circulating β-hydroxybutyrate concentrations were decreased (0.51 ± 0.01 vs. 0.70 ± 0.01 mmol/L for GLUC vs. CTRL, respectively) but plasma fatty acids, progesterone, and insulin concentrations were unaffected by treatment. Treatment did not affect either uterine lumen fluid glucose concentration or the mRNA abundance of specific glucose transporters in the endometrium. Mean conceptus length, width, and area on d 14 were reduced in the GLUC treatment compared with the CTRL treatment. A greater proportion of embryos in the CTRL group had elongated to all length cutoff measurements between 11 and 20 mm (measured in 1-mm increments) compared with the GLUC treatment. In conclusion, infusion of glucose into lactating dairy cows from d 7 to d 14 post-estrus during the critical period of conceptus elongation had an adverse impact on early embryonic development.

Interferon tau-dependent and independent effects of the bovine conceptus on the endometrial transcriptome†

“…Interestingly, in a recent study from our group, glucose infusion into late lactation dairy cows from days 7 to 14 post estrus had an adverse impact on early embryonic development; transfer of day 7 blastocysts to lactating dairy cows reduced mean conceptus length, width, and area on day 14. In addition, a greater proportion of embryos in the control group had elongated to >16 mm in length compared to the glucose infused group [68]. Considering the importance of glucose during development of the ovine conceptus, investigation of intrauterine glucose concentrations during elongation of the bovine conceptus may have practical implications.…”

The influence of progesterone on bovine uterine fluid energy, nucleotide, vitamin, cofactor, peptide, and xenobiotic composition during the conceptus elongation-initiation window

“…Whilst the amino acid 15–20 , carbohydrate 20–23 and lipid 2,24,25 composition of bovine uterine luminal fluid (ULF) has been interrogated to some degree, analyses extending to additional biochemicals ( e.g . nucleotide, cofactor and vitamin, xenobiotic, peptide, and energy metabolites) have received very little attention, if any, despite their known importance to, and/or potential impact on, central cellular processes.…”

Letter to the Editor: About glucose and early embryo development in cows described by Leane et al. (2018)

“…First, the relationship between plasma glucose and uterine luminal fluid glucose levels is not known; Leane et al (2018) detected no difference in uterine luminal fluid glucose levels between the glucose infusion and control (saline infusion) groups. Second, the baseline plasma glucose levels of lactating cows in this study were already at the higher level reported for heifers or nonlactating cows in previous studies (Maillo et al, 2012;Garverick et al, 2013;Forde et al, 2016), suggesting that the glucose infusion that increased levels by ~10 mg/dL in Leane et al (2018) did not really address an insufficiency. Irrespective, it remains quite surprising that glucose infusion did not affect plasma insulin and nonesterified fatty acids, as could be anticipated in late-lactating dairy cows.…”

“…Moreover, dairy heifers have inherently higher plasma glucose than high-yielding dairy cows and lower embryonic mortality (Rizos et al, 2010). In a recent publication, Leane et al (2018) asked whether increasing plasma glucose by intravenous supplementation could improve fertility in late-lactating dairy cows (Leane et al, 2018). They describe changes in conceptus development following a constant intravenous glucose infusion for 1 wk after embryo transfer.…”

“…Irrespective, it remains quite surprising that glucose infusion did not affect plasma insulin and nonesterified fatty acids, as could be anticipated in late-lactating dairy cows. Given this context, it is highly unlikely that glucose infusion had a direct effect on embryo elongation as presumptively discussed in Leane et al (2018). Therefore, the role of glucose in preimplantation bovine embryo development remains unresolved and an important question in need of research.…”