Practical aspects of achieving positive energy balance in low birth weight infants

Nutritional and physiological role of medium-chain triglycerides and medium-chain fatty acids in piglets

Medium-chain fatty acids (MCFAs) are found at higher levels in milk lipids of many animal species and in the oil fraction of several plants, including coconuts, palm kernels and certainCupheaspecies. Medium-chain triglycerides (MCTs) and fatty acids are efficiently absorbed and metabolized and are therefore used for piglet nutrition. They may provide instant energy and also have physiological benefits beyond their energetic value contributing to several findings of improved performance in piglet-feeding trials. MCTs are effectively hydrolyzed by gastric and pancreatic lipases in the newborn and suckling young, allowing rapid provision of energy for both enterocytes and intermediary hepatic metabolism. MCFAs affect the composition of the intestinal microbiota and have inhibitory effects on bacterial concentrations in the digesta, mainly onSalmonellaand coliforms. However, most studies have been performedin vitroup to now andin vivodata in pigs are still scarce. Effects on the gut-associated and general immune function have been described in several animal species, but they have been less studied in pigs. The addition of up to 8% of a non-esterified MCFA mixture in feed has been described, but due to the sensory properties this can have a negative impact on feed intake. This may be overcome by using MCTs, allowing dietary inclusion rates up to 15%. Feeding sows with diets containing 15% MCTs resulted in a lower mortality of newborns and better development, particularly of underweight piglets. In conclusion, MCFAs and MCTs offer advantages for the improvement of energy supply and performance of piglets and may stabilize the intestinal microbiota, expanding the spectrum of feed additives supporting piglet health in the post-weaning period.

Pragmatic approach to in-hospital nutrition in high-risk neonates

Extremely low birth weight infants may experience periods of moderate to severe undernutrition during the acute phase of their respiratory problems. This undernutrition contributes to early growth deficits in these patients and may have long-lasting effects, including poor neurodevelopmental outcome. Early postnatal intravenous amino-acid administration and early enteral feeding strategies will minimize the interruption of nutrient intake that occurs with premature birth. These two strategies will prevent intracellular energy failure, allow the administration of more non-protein energy, as well as enhance overall nutritional health, as evidenced by less postnatal weight loss and earlier return to birth weight, and improved overall postnatal growth and outcome.

Energy intake, metabolic balance and growth in preterm infants fed formulas with different nonprotein energy supplements

OBJECTIVE

To study metabolic and energy balances, growth and composition of increased body mass in healthy preterm infants fed control formula or control formula with three different nonprotein energy supplements.

PATIENTS AND METHODS

Growing preterm infants (birth weight < 1,500 g and gestational age < 31 weeks) were fed standard preterm formula (control group) or the same formula enriched with three different nonprotein energy supplements. An energy supplement of 23 kcal/kg/day was achieved by adding medium-chain triglyceride and dextrinomaltose in three different caloric ratios: 33:66 in group A, 66:33 in group B, and 85:15 in group C. Energy balance was determined by open-circuit continuous (5-6 hours) measurements of energy expenditure, with simultaneous measurement of 24-hour urinary nitrogen excretion. Metabolic balance was determined by measurements of energy intake, energy oxidation, and energy output in urine and stool. The composition of body mass accretion was determined as the accretion of fat and protein in the total weight gain.

RESULTS

The fat accretion (4.9, 5.9, 6.2, and 3.8 g/kg/day in groups A, B, C and D, respectively) correlated directly with fat intake. Infants receiving standard energy intake had a fat percentage of weight gain significantly lower (28%) than that of the high-energy intake groups (31%, 40%, and 38% in groups A, B, and C, respectively). This difference corresponded to the results obtained from skinfold thickness measurements.

CONCLUSIONS

Excess nonprotein energy is stored as fat regardless of its source (fat or carbohydrate). High caloric and medium-chain triglyceride intake in otherwise healthy growing preterm infants does not promote nitrogen retention.

Stability of respiratory quotient and growth outcomes of very low birth weight infants

Nutritional management of very low birth weight (VLBW) infants involves promoting growth at rates that mimic intrauterine rates. Nutritional intake at the recommended energy level to promote growth results in fat accretion at levels that exceed intrauterine rates for fat accretion. The respiratory quotient (RQ), the ratio of carbon dioxide produced to oxygen consumed during oxidation, provides a measure of the percentage of substrates used for energy. An RQ of greater than 0.9 indicates carbohydrate is used to meet energy needs, allowing the majority of fat intake to be stored as new tissue. The purpose of this study was to examine the stability of the RQ across time in relation to nutritional intake and growth in VLBW infants. Subjects were 9 enterally fed VLBW infants. Measurements to determine the RQ were obtained weekly for 3 weeks by indirect calorimetry. Nutritional intake and growth velocity were examined. There was no significant difference in the RQ across 3 weeks. The mean (+/- SD) RQs for each of the 3 weeks were 1.08 (+/- 0.04), 1.06 (+/- 0.05), and 1.06 (+/- 0.07), respectively. No significant differences were found across the 3 weeks for any of the macronutrient variables. Growth velocity for the period was 15.7 g/kg/day. By discharge from the NICU, 66% of the infants had weights less than the 10th percentile on an intrauterine growth reference. An RQ greater than 1.0 indicates VLBW infants are depositing excess fat. However, increased accretion rates of fat did not improve the growth outcomes of these VLBW infants.

Effects of early nutrition on free radical formation in VLBW infants with respiratory distress

OBJECTIVE

We studied the development of essential fatty acid deficiency (EFAD) and its effects together with those of vitamin E deficiency on the free radical formation of very low birth weight (VLBW) infants with respiratory distress.

METHODS

Infants were divided into three groups based on the way each was supplied with daily total energy intake: (1) by fat free parenteral nutrition only or by nutrition composed of (2) less than or (3) higher than 25% of total daily energy intake given in oral feeding. We measured plasma lipid parameters and autoxidative susceptibility (AOS) of red blood cells (RBCs).

RESULTS

Plasma concentrations of linoleic acid were low in all the groups. After at least 14 days of feeding, eicosatrienoic acid (EA) was not detected. One week after the introduction of oral feeding, the abnormal triene/tetraene ratio of the groups had decreased, but was not normalized. Vitamin E deficiency was associated with significantly increased AOS, but EFAD was not. The two factors together caused an increase of AOS, that was additive.

CONCLUSIONS

Our data confirm that EFAD increases AOS of RBCs in VLBW infants. We assume that prevention of EFAD in VLBW infants could decrease the prevalence of complications associated with free radical formation.

Amino acid and energy needs of pediatric patients receiving parenteral nutrition

The technique of parenteral nutrition has become such an established part of modern pediatric care that it is difficult to imagine how pediatricians, as recently as 25 years ago, managed a large group of very difficult patients; however, despite its obvious nutritional advantages, the technique is not without problems. Many of these can be circumvented or controlled by careful attention to all aspects of the technique. Certainly the incidence of these problems can be maintained at a level sufficiently low that the benefits of the technique far outweigh its risks; however, the technique clearly can be further improved. One requirement for doing so is to recognize that the technique is deceptively simple and that it should not be used indiscriminantly without careful consideration of indications and alternative strategies for nutritional management. Additional research also is required. As discussed earlier, the available parenteral amino acid mixtures and lipid emulsions, although considerably improved over earlier versions, remain far from optimal. Some of the actual and theoretic problems that should be addressed in the near future are discussed in the preceding sections; there also are many others.

Nutrient needs of the preterm infant

Preterm infants exhibit special nutrient needs that differ substantially from other patient populations. Special characteristics include increased energy and protein requirements that must be addressed to prevent tissue catabolism and support growth. The immaturity of some organ systems may also complicate the administration of nutrition support. This article describes important characteristics of enteral and parenteral nutrition as it applies to the preterm infant.