Lactose in milk replacer can partly be replaced by glucose, fructose, or glycerol without affecting insulin sensitivity in veal calves

Abstract

Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body weight >100 kg). Replacement of lactose by other dietary substrates can be economically attractive, and may also positively (or negatively) affect the risk of developing problems with glucose metabolism. An experiment was designed to study the effects of replacing one third of the dietary lactose by glucose, fructose, or glycerol on glucose homeostasis and insulin sensitivity in veal calves. Forty male Holstein-Friesian (body weight = 114 ± 2.4 kg; age = 97 ± 1.4 d) calves were fed an MR containing 462 g of lactose/kg (CON), or an MR in which 150 g of lactose/kg of MR was replaced by glucose (GLU), fructose (FRU), or glycerol (GLY). During the first 10 d of the trial, all calves received CON. The CON group remained on this diet and the other groups received their experimental diets for a period of 8 wk. Measurements were conducted during the first (baseline) and last week of the trial. A frequently sampled intravenous glucose tolerance test was performed to assess insulin sensitivity and 24 h of urine was collected to measure glucose excretion. During the last week of the trial, a bolus of 1.5 g of [U-13 C] substrates was added to their respective meals and plasma glucose, insulin, and 13 C-glucose responses were measured. Insulin sensitivity was low at the start of the trial and remained low [1.2 ± 0.1 and 1.0 ± 0.1 (mU/L) −1 × min −1 ], and no treatment effect was noted. Glucose excretion was low at the start of the trial (3.4 ± 1.0 g/d), but increased in CON and GLU calves (26.9 ± 3.9 and 43.0 ± 10.6 g/d) but not in FRU and GLY calves. Postprandial glucose was higher in GLU, lower in FRU, and similar in GLY compared with CON calves. Postprandial insulin was lower in FRU and GLY and similar in GLU compared with CON calves. Postprandial 13 C-glucose increased substantially in FRU and GLY calves, indicating that calves are able to partially convert these substrates to glucose. We concluded that replacing one third of lactose in MR by glucose, fructose, or glycerol in MR differentially influences postprandial glucose homeostasis but does not affect insulin sensitivity in veal calves.

Short communication: Supplementation of fructo-oligosaccharides does not improve insulin sensitivity in heavy veal calves fed different sources of carbohydrates

“…These problems have been identified in heavy veal calves (4-6 mo), characterized by a high incidence of hyperglycemia, hyperinsulinemia, and glucosuria (Hostettler-Allen et al, 1994;Hugi et al, 1997) and insulin resistance (Pantophlet et al, 2016a). In a recent study, we found that calves raised on a lactose MR diet, or diets in which one-third of the lactose was replaced by glucose, fructose, or glycerol, did not differ in insulin sensitivity and that insulin sensitivity was low (Pantophlet et al, 2016c). This could lead to metabolic disorders and impaired animal growth performance.…”

“…All calves remained on their diets throughout the trial. A detailed description of the diets and feeding strategy is provided elsewhere (Pantophlet et al, 2016c). In short, calves were fed MR and solid feed (20% wheat straw and 80% concentrates) twice a day, at 0630 and 1530 h. The MR was fed on an individual basis (BW was measured weekly), and solid feed was provided per pen during group housing and per individual calf when the calves were housed in metabolic cages.…”

Symposium review: Macronutrient metabolism in the growing calf

“…In agreement, Kesser et al (2017) recently concluded that even though slight changes in insulin sensitivity may be provoked by early life nutrition, these effects are rather transient and they found no evidence for sustained effects. In heavy calves, insulin sensitivity is invariably low, being rather insensitive to the carbohydrate source in the CMR (Pantophlet et al, 2016c) or to an exchange of lactose for fat (euglycemic-hyperinsulinemic clamp; Pantophlet et al, 2016a). Large effects of dietary treatments on postprandial glucose and insulin responses, as often observed (e.g., Vicari et al, 2008a,b), are therefore unlikely to be caused by differences in insulin sensitivity.…”

“…Insulin sensitivity in calves rapidly drops with age. Stanley et al (2002), found 10-to 20-fold higher insulin sensitivities in Holstein and Jersey calves at 4 to 5 wk of age [15 and 25 × 10 −4 (mU/L) −1 × min −1 , respectively], than Pantophlet et al (2016c) in Holstein calves of about 190 kg of BW, both using the frequently sampled intravenous glucose tolerance test (FSIGT). Recent developments in feeding strategies of heifer calves have renewed interest in manipulating insulin sensitivity in early life, based on the promise of improved performance and milk production in later life.…”

The use of metabolic profiling to identify insulin resistance in veal calves

“…Persistently high intakes of lactose and fat may lead to dysregulations in glucose homeostasis, which are characterized by a high incidence of hyperglycemia, hyperinsulinemia and glycosuria. These problems have been identified in heavy (4–6 months old) veal calves [1–3]. In addition, a substantial decrease in insulin sensitivity is observed in calves during the first months of life [4, 5].…”