EFFECTS OF A DUODENAL GLUCOSE-INFUSION ON THE RELATIONSHIP BETWEEN PLASMA-CONCENTRATIONS OF GLUCOSE AND INSULIN IN DAIRY-COWS

Citation
S. Lemosquet et al., EFFECTS OF A DUODENAL GLUCOSE-INFUSION ON THE RELATIONSHIP BETWEEN PLASMA-CONCENTRATIONS OF GLUCOSE AND INSULIN IN DAIRY-COWS, Journal of dairy science, 80(11), 1997, pp. 2854-2865
Citations number
49
Journal title
ISSN journal
00220302
Volume
80
Issue
11
Year of publication
1997
Pages
2854 - 2865
Database
ISI
SICI code
0022-0302(1997)80:11<2854:EOADGO>2.0.ZU;2-4
Abstract
The effects of duodenal infusion of glucose on the relationship betwee n plasma concentrations of glucose and insulin and on milk composition were investigated in a crossover design. Eight dairy cows were contin ually infused with water (control) or glucose (1.5 kg/d). Cows receive d diets consisting of dehydrated whole-plant maize in restricted amoun ts to equalize the energy supply between treatments. Basal (before mea l) plasma concentrations of glucose and insulin were increased, but co ncentrations nonesterified fatty acids (NEFA) were decreased, by gluco se treatment. During the first 2 h after feed distribution, plasma ins ulin increased, and plasma glucose and NEFA decreased, in both control and treated cows. Afterward, plasma glucose increased in treated cows but further decreased in control cows. The difference reached 8 mg/10 0 ml without any change in plasma insulin. During the meal, concentrat ions of growth hormones in plasma were inhibited to a similar extent i n both groups. In response to intravenous glucose or insulin challenge s, changes in plasma glucose, NEFA, and insulin stimulated by glucose were also very similar in both groups. In conclusion, duodenal infusio n of glucose increased basal plasma concentrations of glucose and insu lin, increased postprandial plasma glucose, and decreased NEFA without inducing insulin resistance. Glucose treatment did not change milk yi eld but decreased milk fat yield, mainly through a decrease in the yie ld of C-18 fatty acids that were derived from circulating fatty acids. In the absence of insulin resistance, the decrease in the yield of C- 18 fatty acids might be attributed to an inhibition of adipose lipolys is or an increase in adipose lipogenesis.