Research and Reviews: Dairy

Special Circular 163-99

Changes of Plasma Fructose and Glucose When Simple Sugars Are Used as Energy Supplements for New Born Calves

H. L. Keller
L. I. Gherman
R. E. Kosa
D. C. Borger
W. P. Weiss
L. B. Willett 1
The Ohio State University
Department of Animal Sciences

1 For more information, contact at: The Ohio State University, Ohio Agricultural Research and Development Center, 128 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH 44691; 330-263-3792; willett.2@osu.edu

Abstract

Shortly after birth, blood plasma sugar concentrations of newborn calves decline below desired concentrations. Two trials were conducted to determine if plasma fructose and glucose can be stabilized by feeding calves fructose or lactose. The short-term trial consisted of six calves receiving supplements of either 40 grams of fructose, lactose, or water (control) with colostrum replacer at one and 96 hours after birth. Rectal temperatures and plasma glucose and fructose concentrations were monitored at close intervals for 12 hours post-supplement. In the long-term trial, 15 calves received 40 grams of either lactose, fructose, or water (control) in the initial feeding given at one hour postpartum and to the subsequent feedings given at 12-hour intervals for 81 hours. Plasma glucose and fructose concentrations were determined before and four hours after each of the seven supplements. Supplements of fructose fed soon after birth suppressed plasma glucose and increased plasma fructose. Pre-feeding plasma glucose concentrations of all groups stabilized (~100 mg/dL) by 25 hours after birth. After 25 hours, lactose supplements increased post-feeding concentrations of plasma glucose (169.7 ± 8.2 mg/dL) above those of the other calves. Plasma fructose was not detected in control or lactose-supplemented calves beyond 17 hours postpartum but was detectable in the fructose-supplemented calves through 77 hours. Fructose-supplemented calves also had higher rectal temperatures than the other calves at eight and 10 hours after birth. Both fructose and glucose concentrations were changing rapidly in the hours following parturition, and the oral sugar supplements appeared to increase the overall plasma sugar concentrations of the treated calves.

Introduction

Birth is very stressful for the newborn, and many adjustments, such as maintaining internal stability, must be made quickly and efficiently to ensure survival in the new environment. The changing plasma glucose and fructose concentrations are indicative of the metabolic adaptations taking place.

Glucose is thought to be the primary energy source of the fetus and newborn, even though plasma fructose concentrations are elevated in calves and lambs before birth and immediately following parturition (Daniels et al., 1974; Becker et al., 1997). Plasma glucose is metabolized quickly following parturition, forcing the newborn to use an alternative energy source (Faulkner, 1983). Newborns may be able to depend on the plasma fructose until plasma glucose concentrations stabilize; however, this does not occur until approximately 18 hours after birth (Daniels et al., 1974; Kurz and Willett, 1991). Fructose concentrations rapidly decline after birth, decreasing by about one-half every three hours (Kurz and Willett, 1992). Because the concentrations of both sugars vary following parturition, the calf may experience periods when energy availability is not sufficient to maintain internal stability. In light of these apparent metabolic changes, sugar supplements may be of assistance. Studies by Daniels et al. (1979, 1981) have shown that the infusion of fructose or sorbitol supplements was beneficial to newborn calves by increasing early postnatal weight gain.

The objectives of this study were to determine the changes over time of plasma glucose and fructose after administering oral sugar supplements and to determine whether these multiple supplements can maintain elevated glucose and fructose concentrations.

Materials and Methods

To prevent nursing, calves were removed from the dams immediately following birth and housed in individual pens bedded with wood shavings. Calves were also dried, weighed, and had their navels treated with iodine following parturition. The short-term trial utilized close-interval sampling to monitor detailed changes in the concentrations of plasma glucose and fructose.

These calves received a single 40-gram dose of either lactose, fructose, or water within one hour of birth. The sugar supplements were dissolved in 40 ml of water and administered orally by means of a syringe. Following the supplement, each calf was fed Life Boost (Agrilabs, St. Joseph, Mo.), a dehydrated colostrum substitute dissolved in two quarts of warm water. The calves received a second 40-gram supplement, 96 hours after birth, dissolved in two quarts of milk. If a calf did not voluntarily drink the entire supplement, the remaining amount was given by means of an esophageal tube.

Blood samples were collected 0.5 hours after birth, prior to administration of the sugar supplement. Additional samples were collected at 1, 2, 3, 4, 5, 6, 8, 10, and 12 hours post-supplement. The concentrations of both fructose and glucose were determined in blood samples. Rectal and environmental temperatures were recorded at the time of each sample collection. The same schedule was used with the second supplement given 96 hours after birth.

The long-term study was conducted to determine when plasma sugar concentrations stabilized and how sequential administration of supplements would affect the calves. Sample times were less intense and based upon optimum sugar concentrations obtained from the short-term trial. Supplemented calves received a total of seven 40-gram sugar supplements of either fructose or lactose with their daily feedings, while control calves received nonsupple-mented feed. The initial supplement was dissolved in two quarts of Life Boost and fed within one hour of birth. The calves were fed an amount equal to 4% of their body weight for the remaining feedings. The dam's colostrum was used for the second feeding. The last five feedings of milk were given at 0700 and 1900 daily.

As in the short-term trial, initial jugular blood samples were collected 0.5 hours after birth, prior to supplementing the calves. The second sample was collected four hours after the first feeding. Thirteen additional samples were collected throughout the trial prior to and four hours after each of the six remaining feedings. Blood samples were processed and analyzed the same as those collected during the short-term trial. Rectal and environmental temperatures were recorded with the collection of each blood sample.

Calf weight was measured at birth, daily for seven days, and weekly for six weeks. Calf health was evaluated by checking signs of clinical illness and scours twice daily.

Results and Discussion

Plasma Sugar Concentrations

Parturition is a demanding process, forcing newborn calves to initially rely on energy reserves accumulated during gestation and later to shift to an alternative source. Frequently, newborns experience a decrease in plasma glucose concentrations following parturition (Daniels et al., 1974). Control calves exhibited a decrease within four hours in both the short-term (68.8 ± 23.7 to 40.0 ± 5.2 mg/dL) and long-term trials (60.5 ± 14.5 to 42.0 ± 8.9 mg/dL). To compensate for this decline, Mersmann (1974) suggested that the low glucose concentrations and shivering of the cold-stressed newborns stimulated production of phosphorylase, which aids in restoring plasma glucose concentrations (~100 mg/dL) by means of the glycogen reserves. However, the glycogen reserves are depleted shortly after parturition and are not replenished until a few days postpartum when gluconeogenic enzymes reach substantial levels of activity (Faulkner, 1983). The calf must therefore depend on other energy sources during the hours immediately following parturition. Fructose accumulated during gestation can be used as an energy source when plasma glucose is low (Faulkner, 1983). The decrease of plasma fructose in control calves during the first 17 hours following birth may be indicative of the importance of fructose as an energy source (Curtis et al., 1966; Kurz and Willett, 1992).

Although no differences in the concentrations of plasma fructose (52.2 ± 5.7, 49.5 ± 4.7 mg/dL for short- and long-term trials, respectively) or glucose (74.2 ± 11.1, 62.9 ± 12.0 mg/dL for short- and long-term trials respectively) were found among calves at birth, plasma profiles of the control and supplemented calves began to differ after administration of the supplements (Figures 1 and 2).

Fructose Supplements

Plasma fructose concentrations began decreasing by one-half every three hours after birth in control and by one-half every 2.5 hours in lactose-treated calves (Figures 1 and 2). Intravenous and oral supplements of fructose have been reported to help increase plasma fructose concentrations in newborn calves (Daniels et al., 1974; Becker et al., 1997). In contrast to the control and lactose-treated calves, plasma fructose concentrations increased significantly after fructose-treated calves received their first supplement. Similarly, in the long-term trial, administration of multiple fructose supplements elevated plasma fructose concentrations for 42 hours after birth (Figure 2), almost twice as long as calves given a single supplement (Daniels et al., 1974; Kurz and Willett, 1992). While fructose concentrations were elevated, glucose concentrations were suppressed, a pattern similar to that observed by Becker et al. (1997). Daniels et al. (1974) suggested this suppression of plasma glucose resulted from an inhibitory mechanism activated by the elevated plasma fructose, thus allowing the calf to use dietary glucose to replenish its depleted glycogen reserves instead of as a energy source.

Figure 1. Concentrations (mean ± SE) of plasma fructose (A) and glucose (B)
in control calves (closed square) and calves receiving a single 40-gram lactose (open triangle) or
fructose (closed circle) supplement one hour postpartum during the short-term trial.

Figure 2. Concentrations (mean ± SE) of plasma fructose (A) and glucose (B)
in control calves (closed square) and calves receiving 40-gram lactose (open triangle) or
fructose (closed circle) supplements at 12-hour intervals for 81 hours following birth
during the long-term trial.

In the long-term trial, post-supplement fructose concentrations of the fructose-supplemented calves began to decrease by 17 hours after birth, suggesting an increase in the efficiency of fructose metabolism. Even though concentrations were decreasing, plasma fructose concentrations remained higher in the fructose-treated calves through 77 hours. Similar changes in fructose kinetics were observed during the short-term trial with supplements having no effect on plasma sugar concentrations when administered 96 hours postpartum.

Plasma glucose recovered from the low postpartum concentrations and pre-feeding concentrations stabilized by 25 hours postpartum (90.3 ± 7.2, 100.9 ± 4.2, and 95.8 ± 7.4 mg/dL for control, lactose-, and fructose-treated calves, respectively) suggesting that gluconeogenic enzymes had become active, and the plasma concentrations could be maintained. Simultaneously, post-feeding fructose concentrations of the fructose-treated calves began decreasing. These changes support the hypothesis that fructose is utilized mainly when plasma glucose concentrations are low (Faulkner, 1983).

Lactose Supplements

Lactose supplements at birth did not prevent plasma fructose concentrations from decreasing. Lactose-treated calves did, however, have higher concentrations of plasma glucose than the other calves by two hours post-supplement (Figure 1). A similar increase in glucose concentrations was reported by Becker et al. (1997). The breakdown of lactose into glucose and galactose, from both the supplements and the milk, may have been responsible for the increases in plasma glucose concentrations observed in both control and lactose-treated calves at 29, 41, 53, 65, and 77 hours (Figure 2). The decrease in post-supplement glucose concentrations observed with maturity may reflect an increase in efficiency with which glucose is converted to glycogen (Faulkner, 1983).

Rectal Temperature

All calves experienced a decrease in temperature immediately after parturition (Figures 3 and 4). To compensate for the decrease in rectal temperature occurring at birth, newborns apparently increase glucose metabolism. This source of metabolic heat is depleted and prevents the calves from stabilizing their rectal temperatures prior to 49 hours postpartum, a time which coincides with the stabilizing plasma glucose concentrations (Figure 4). If the calf can use fructose during this period, it has been hypothesized that an increase in plasma fructose concentrations would increase the amount of heat generated, causing a subsequent rise in rectal temperature. Studies by Curtis et al. (1966) and Becker et al. (1997) did not show an increase in rectal temperatures of supplemented newborn piglets and calves. Calves receiving fructose supplements one hour after birth during the short-term trial had higher rectal temperatures by eight hours than calves not receiving fructose (Figure 3), suggesting that the additional 180 kilocalories provided by the supplement may be beneficial. However, the administration of sugar supplements for 81 hours postpartum, during the long-term trial, did not affect the rectal temperatures of treated calves (Figure 4).

Figure 3. Rectal temperatures (mean ± SE) with third order regressions of
control calves (A) and calves receiving a single 40-gram lactose (B) or fructose
(C) supplement one hour postpartum during the short-term trial.

Figure 4. Rectal temperatures (mean ± SE) with third order regressions of
control calves (A) and calves receiving 40-gram lactose (B) or fructose (C)
supplements at 12-hour intervals for 81 hours following birth during the
long-term trial.

Body Weight and Health

Daniels et al. (1979) and Kurz et al. (1987) observed that calves receiving fructose injections at birth weighed more at five weeks than non-injected calves. No such differences in weight gain were observed during this study. The sugar supplements also had no observable effect on the overall health of the calves.

Conclusion

This study showed that the mechanisms of sugar metabolism change quickly in the hours following parturition. Enzymes and pathways continue to develop after birth, allowing for an increase in the metabolic efficiency of sugar utilization. The age of the neonate and time since last feeding are both critical factors influencing the interpretation of data on plasma sugar concentrations. Fructose supplements given within one hour of birth increased the concentration of plasma fructose, whereas supplements given at 96 hours after birth had little effect on the sugar concentrations. The effect of lactose supplements also changed with maturity. Both fructose and lactose supplements administered shortly after birth increased the overall plasma sugar concentrations in comparison with unsupplemented calves. Calves receiving the fructose supplements were able to increase their rectal temperatures sooner than other calves, suggesting these calves may have an advantage when coping with birth-related stresses.

References

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