Plasma concentrations of glucagon-like peptide 1 and 2 in calves fed calf starters containing lactose

Abstract

The objective of this study was to evaluate the effects of lactose inclusion in calf starters on plasma glucagon-like peptide (GLP)-1 and GLP-2 concentrations and gastrointestinal tract development in calves. Holstein bull calves (n = 45) were raised on an intensified nursing program using milk replacer containing 28.0% CP and 15.0% fat, and were fed a texturized calf starter containing 0 (control), 5.0 (LAC5), or 10.0% (LAC10; n = 15 for each treatment) lactose on a DM basis. Lactose was included in the starter by partially replacing dry ground corn in pelleted portion of the starter. All calf starters were formulated with 23.1% CP. The ethanol-soluble carbohydrate concentrations of the control, LAC5, and LAC10 starters were 7.3, 12.3, and 16.8% on a DM basis, respectively. Starch concentrations of the control, LAC5, and LAC10 starters were 29.7, 27.0, and 21.4% on a DM basis, respectively. All calves were fed treatment calf starters ad libitum. Blood samples were obtained weekly from 1 to 11 wk of age, and used to measure plasma GLP-1, GLP-2, and insulin concentrations, serum β-hydroxybutyrate (BHB) concentration, and blood glucose concentration. At 80 d of age, calves were euthanized, and weights of the reticulorumen, omasum, abomasum, small intestine, and large intestine tissue were measured. Serum BHB concentration was higher for calves fed the LAC10 (171 μmol/L) starter than for those fed the control (151 μmol/L) and LAC5 (145 μmol/L) starters. Plasma GLP-1 and GLP-2 concentrations did not differ between treatments. However, relative to the baseline (1 wk of age), the plasma GLP-1 concentration was higher for the LAC10 (125.9%) than for the LAC5 (68.2%) and control (36.8%), and for the LAC5 than for the control (36.8%). Moreover, similar differences between treatments were observed for GLP-2 concentration relative to the baseline (88.2, 76.9, and 74.9% for LAC10, LAC5, and control treatments, respectively). The serum BHB concentration was positively correlated with the plasma GLP-1 concentration (r = 0.428). Furthermore, the plasma GLP-1 concentration was positively correlated with the insulin concentration (r = 0.793). The weights of the reticulorumen, omasum, abomasum, small intestine, and large intestine were not affected by the treatments. In conclusion, inclusion of lactose in calf starters resulted in higher plasma GLP-1 and GLP-2 concentrations, and BHB might be associated with higher plasma GLP-1 concentration.

The effect of tributyrin supplementation to milk replacer on plasma glucagon‐like peptide 2 concentrations in pre‐weaning calves

“…A time effect was observed for plasma GLP‐2 concentration ( p < 0.01; Figure ), and plasma GLP‐2 concentration was the highest at the beginning of this study and decreased from 1 to 3 weeks after birth in both CON and TB. This fluctuation of plasma GLP‐2 concentration was similar to that observed in our previous study (Inabu et al, ). A treatment effect was observed for plasma GLP‐2 concentration ( p = 0.02): mean plasma concentration of GLP‐2 among whole period was significantly higher for TB (0.60 ± 0.05 ng/ml) compared with CON (0.41 ± 0.05 ng/ml).…”

“…In both treatments, blood glucose concentration, reflected by the amount of MR fed, increased from 2 weeks after birth, maintained at high concentration until 7 weeks after birth and decreased at weaning (Time p < 0.01; Figure a), consistent with previous results where blood glucose concentration fluctuated according to the amount of MR fed (Inabu et al, ). Although starter DMI and ME intake were lower for TB than for CON, blood glucose concentration did not differ between the two treatments, which might support our speculation of an improved nutrient absorption in TB calves.…”

“…A treatment effect was observed for plasma GLP‐2 concentration ( p = 0.02): mean plasma concentration of GLP‐2 among whole period was significantly higher for TB (0.60 ± 0.05 ng/ml) compared with CON (0.41 ± 0.05 ng/ml). In our previous studies, it was indicated that plasma GLP‐2 concentration was affected by feeding method of first colostrum (Inabu et al, , ). As described above, feeding method of colostrum feeding is similar among dairies and serum total protein concentration and albumin‐globulin ratio did not differ between treatment groups, thus, greater GLP‐2 concentration for TB from 7 days after birth may not be due to difference in feeding method of colostrum.…”

“…Plasma and whole blood samples were analyzed for GLP‐2 and glucose concentrations, respectively, and serum samples were analyzed for insulin‐like growth factor 1 (IGF‐1) and β‐hydroxybutyric acid (BHBA) concentrations. Plasma GLP‐2 concentration was measured by a time‐resolved fluoroimmunoassay technique previously described by Sugino et al () using a solid‐phase competition immunoassay with Eu‐labeled human GLP‐2 (Peptide Institute, Inc., Osaka, Japan), polyclonal anti‐rat GLP‐2 (Yanaihara Institute, Inc., Shizuoka, Japan), and polystyrene microtiter strips coated with goat‐anti‐rabbit γ‐globulin (Elsabagh et al, ; Inabu et al, ). Intra‐ and inter‐assay CVs were 2.7 and 2.2%, respectively, and the least detectable level was 0.042 ng/ml.…”

“…The samples were ground using a hammer mill (SM1; Retsch GmbH, Haan, Germany) with a 1mm screen, and analyzed by Zen-Raku-Ren Analysis Center (Kamisu, Ibaraki, Japan) for dry matter (DM), ash, crude protein (CP), fat, and starch according to AOAC (1990), for neutral detergent fiber (NDF) and acid detergent fiber (ADF) according to AOAC International (2002), and for water-soluble carbohydrate (WSC) concentration using anthrone assay according to Hall, Hoover, Jennings, and Miller Webster (1999). Metabolizable energy (ME) for MR, starter, and kleingrass were calculated according to National Research Council Institute, Inc., Osaka, Japan), polyclonal anti-rat GLP-2 (Yanaihara Institute, Inc., Shizuoka, Japan), and polystyrene microtiter strips coated with goat-anti-rabbit γ-globulin (Elsabagh et al, 2017;Inabu et al, 2017). Intra-and inter-assay CVs were 2.7 and 2.2%, respectively, and the least detectable level was 0.042 ng/ml.…”