Human milk cream alters intestinal microbiome of preterm infants: a prospective cohort study.

BACKGROUND: In very low birth weight (VLBW) infants, human milk cream added to standard human milk fortification is used to improve growth. This study aimed to evaluate the impact of cream supplement on the intestinal microbiome of VLBW infants. METHODS: Whole genome shotgun sequencing was performed on stool (n = 57) collected from a cohort of 23 infants weighing 500-1250 grams (control = 12, cream = 11). Both groups received an exclusive human milk diet (mother's own milk, donor human milk, and donor human milk-derived fortifier) with the cream group receiving an additional 2 kcal/oz cream at 100 mL/kg/day of fortified feeds and then 4 kcal/oz if poor growth. RESULTS: While there were no significant differences in alpha diversity, infants receiving cream significantly differed from infants in the control group in beta diversity. Cream group samples had significantly higher prevalence of Proteobacteria and significantly lower Firmicutes compared to control group. Klebsiella species dominated the microbiota of cream-exposed infants, along with bacterial pathways involved in lipid metabolism and metabolism of cofactors and amino acids. CONCLUSIONS: Cream supplementation significantly altered composition of the intestinal microbiome of VLBW infants to favor increased prevalence of Proteobacteria and functional gene content associated with these bacteria. IMPACT: We report changes to the intestinal microbiome associated with administration of human milk cream; a novel supplement used to improve growth rates of preterm very low birth weight infants. Since little is known about the impact of cream on intestinal microbiota composition of very low birth weight infants, our study provides valuable insight on the effects of diet on the microbiome of this population. Dietary supplements administered to preterm infants in neonatal intensive care units have the potential to influence the intestinal microbiome composition which may affect overall health status of the infant.

Preterm Pigs Fed Donor Human Milk Have Greater Liver ß-Carotene Concentrations than Pigs Fed Infant Formula.

BACKGROUND: Milk carotenoids may support preterm infant health and neurodevelopment. Infants fed human milk often have higher blood and tissue carotenoid concentrations than infants fed carotenoid-containing infant formula (IF). Donor human milk (DHM) is a supplement to mother's own milk, used to support preterm infant nutrition. OBJECTIVES: We tested whether tissue and plasma ß-carotene concentrations would be higher in preterm pigs fed pasteurized DHM versus premature IF. METHODS: This is a secondary analysis of samples collected from a study of the effects of enteral diet composition on necrotizing enterocolitis incidence. Preterm pigs received partial enteral feeding of either DHM (n = 7) or premature IF (n = 7) from 2 to 7 d of age. The diets provided similar ß-carotene (32 nM), but DHM had higher lutein, zeaxanthin, and lycopene, whereas IF had higher total vitamin A. Plasma, liver, and jejunum carotenoid and vitamin A concentrations were measured by HPLC-PDA. Jejunal expression of 12 genes associated with carotenoid and lipid metabolism were measured. RESULTS: Liver ß-carotene concentrations were higher in DHM- than IF-fed piglets (23 ± 4 compared with 16 ± 2 µg/g, respectively, P = 0.0024), whereas plasma and jejunal ß-carotene concentrations were similar between diets. Liver vitamin A stores were higher in piglets fed IF than DHM (50.6 ± 10.1 compared with 30.9 ± 7.2 µg/g, respectively, P=0.0013); however, plasma vitamin A was similar between groups. Plasma, liver, and jejunum concentrations of lutein, zeaxanthin, and lycopene were higher with DHM than IF feeding. Relative to piglets fed DHM, jejunal low density lipoprotein receptor (Ldlr) expression was higher (61%, P = 0.018) and cluster determinant 36 (Cd36) expression (-27%, P = 0.034) was lower in IF-fed piglets. CONCLUSIONS: Preterm pigs fed DHM accumulate more liver ß-carotene than IF-fed pigs. Future studies should further investigate infant carotenoid bioactivity and bioavailability.

Nutrient Composition of Donor Human Milk and Comparisons to Preterm Human Milk.

BACKGROUND: Human milk is the preferred diet for very low birth weight (VLBW, <1500 g) infants. When mother's own milk is unable to meet the needs of VLBW infants, donor human milk (DHM) is the preferred alternative. Unfortunately, the composition of DHM remains elusive and no comparative studies between preterm human milk and DHM have been performed previously. OBJECTIVES: We aimed to analyze the nutrient content of commercial pooled DHM and compare nutrient content in DHM with that of early and mature preterm human milk. METHODS: We analyzed nutrient content in 15 DHM samples provided from 7 commercial milk banks including calories, carbohydrate, fat, protein, sodium, chloride, potassium, zinc, calcium, phosphorus, magnesium, and vitamin D and compared each nutrient to early (7 d of life) and mature (28 d of life) preterm human milk samples (n = 28-36 per nutrient, gestational age = 28 ± 3 wk). Protein-to-energy ratio and carbohydrate-to-nonprotein energy ratio were calculated for each sample and compared. RESULTS: Mean values for all macro- and micronutrients in DHM are reported. In comparison to early or mature preterm human milk, DHM had significantly lower protein, sodium, chloride, potassium, and zinc content. Calorie, carbohydrate, calcium, phosphorus, magnesium, and vitamin D content did not differ statistically between DHM and early or mature preterm human milk. Fat content was modestly lower in early but not mature human milk when compared with DHM. CONCLUSIONS: We provide mean values for several macro- and micronutrients for DHM and identify key differences between DHM and preterm human milk, which may be considered when designing human milk-based feeding plans. This study was registered at clinicaltrials.gov as NCT05742815.

Fecal Elastase in Preterm Infants to Predict Growth Outcomes.

OBJECTIVES: Preterm infants are born functionally pancreatic insufficient with decreased pancreatic production of lipase and proteases. Developmental pancreatic insufficiency (PI) may contribute to reduced nutrient absorption and growth failure. We sought to determine longitudinal fecal elastase (ELA1) levels in a cohort of preterm infants and whether levels are associated with growth outcomes. METHODS: Prospective observational study of 30 infants 24-34 weeks gestational age and birth weight ≤1250 g fed the exclusive human milk diet, consisting of human milk with human milk-based fortifier. ELA1 was quantified by ELISA during the first 2 weeks of life [Early; 7.5 ± 1.8 days of life (DOL)] and after attainment of full, fortified feedings (Late; 63.6 ± 24.1 DOL). RESULTS: Early ELA1 levels were 192.2 ± 96.4 µg/g, and Late ELA1 levels were 268.0 ± 80.3 µg/g, 39.4% higher (P = 0.01). Infants with early PI (ELA1 < 200 µg/g) were more likely male and of lower gestational age, weight, length, and head circumference at birth. These variables, but not PI status, independently predicted somatic growth. CONCLUSIONS: Fecal ELA1 in preterm infants fed exclusive human milk diet increases with postnatal age. Although pancreatic function in preterm infants may serve as a biological contributor to early postnatal growth failure, additional studies using fecal ELA1 as a predictive biomarker for growth failure are needed in larger cohorts.

Current Patterns of Probiotic Use in U.S. Neonatal Intensive Care Units: A Multi-Institution Survey.

OBJECTIVE: Probiotic supplementation is associated with health benefits in preterm infants. The 2021 American Academy of Pediatrics (AAP) statement on probiotic use advised caution, citing heterogeneity and absence of federal regulation. We assessed the impact of the AAP statement and current institution-wide patterns of probiotic use across neonatal intensive care units (NICU) across the United States. STUDY DESIGN: A cross-sectional web-based institutional survey using REDCap was emailed to 430 Children's Hospital Neonatal Consortium (CHNC) and Pediatrix Medical Group institutions. The survey captured data on probiotic formulations, supplementation, initiation and cessation criteria, reasons for discontinuation, interest in initiating, and AAP statement's impact. RESULTS: Ninety-five (22.1%) hospitals, including 42/46 (91%) CHNC and 53/384 (14%) Pediatrix institutions, completed the survey. Thirty-seven (39%) currently use probiotics. Fourteen different probiotic formulations were reported. The common criteria for initiation were birth weight <1,500 g and gestational age <32 weeks. Parental consent or assent was obtained at only 30% of institutions. Five hospitals (11%) with prior probiotic use discontinued solely due to the AAP statement. Overall, 23 (24%) of hospitals indicated that the AAP statement significantly influenced their decision regarding probiotic use. Nineteen of 51 nonusers (37%) are considering initiation. CONCLUSION: Probiotic use in preterm infants is likely increasing in NICUs across the United States, but significant variability exists. The 2021 AAP statement had variable impact on NICUs' decision regarding probiotic use. The growing interest in adopting probiotics and the significant interhospital variability highlight the need for better regulation and consensus guidelines to ensure standardized use. KEY POINTS: · Probiotic use in preterm infants is likely increasing in U.S. NICUs, but clinical variability exists.. · The AAP statement on probiotic use in preterm infants had a modest impact on current practices.. · There's a need for better product regulation and consensus guidelines to ensure standardized use..

Human milk fortification: the clinician and parent perspectives.

This study reports on the human milk fortification session at the 2019 NEC Society Symposium, which included clinicians and parents discussing the evidence comparing fortification options such as efficacy, safety, cost effectiveness, and the need for parents to be informed about fortifier choice. With the current literature available and the varying standard of care practices for human milk fortification, further studies are needed to determine the most complete diet for preterm infants. The optimal diet would not only provide key nutrients and energy for growth and development, but also improve short- and long-term outcomes. Parents, as advocates and providers for their infant, should be informed, educated, and included in the discussion and decisions regarding fortification of human milk for their infant.

Human Milk Use in the Preoperative Period Is Associated with a Lower Risk for Necrotizing Enterocolitis in Neonates with Complex Congenital Heart Disease.

OBJECTIVE: To evaluate the hypothesis that feeding volumes exceeding 100 mL/kg/d and exposure to cow's milk formula preoperatively increase the risk for preoperative necrotizing enterocolitis (NEC) in infants with complex congenital heart disease. STUDY DESIGN: All infants, of any gestational age, with an isolated cardiac lesion at high risk for NEC (ductal-dependent lesions, transposition of the great arteries, truncus arteriosus, and aorto-pulmonary window) admitted to Texas Children's Hospital from 2010 to 2016 were included. NEC was defined based on the modified Bell criteria. Feeding regimen information and relevant covariates were collected. Logistic regression was used to evaluate the association of feeding regimen and other potential risk factors with NEC. RESULTS: In this single-center, retrospective cohort of 546 infants, 3.3% developed Bell stage I-III NEC preoperatively. An exclusive unfortified human milk diet was associated with a significantly lower risk of preoperative NEC (OR 0.17, 95% CI 0.04-0.84, P = .03) in a multivariable regression model controlling for cardiac lesion, race, feeding volume, birth weight small for gestational age, inotrope use presurgery/pre-NEC, and prematurity. Feeding volumes exceeding 100 mL/kg/d were associated with a significantly greater risk of preoperative NEC (OR 3.05, 95% CI 1.19-7.90, P = .02). CONCLUSIONS: The findings suggest that an unfortified exclusive human milk diet may reduce the risk of preoperative NEC in infants with complex congenital heart disease.

Using formalin fixed paraffin embedded tissue to characterize the preterm gut microbiota in necrotising enterocolitis and spontaneous isolated perforation using marginal and diseased tissue.

BACKGROUND: Necrotising enterocolitis (NEC) is a common cause of death in preterm infants and is closely linked to the gut microbiota. Spontaneous intestinal perforation (SIP) also occurs in preterm neonates, but results in lower mortality and less adverse neonatal outcomes than NEC. Existing studies are largely limited to non-invasive stool samples, which may not be reflective of the anatomical site of disease. Therefore, we analysed historical formalin-fixed paraffin-embedded (FFPE) tissue from NEC and SIP preterm infants. A total of 13 NEC and 16 SIP infants were included. Extracted DNA from FFPE tissue blocks underwent 16S rRNA gene sequencing. For a subset of infants, diseased tissue and marginal healthy tissue from the same infant were compared. RESULTS: Xylene provided a cost and time effective means of deparaffinization. Tissue from the site of disease was highly comparable to adjacent healthier tissue. Comparing only diseased tissue from all infants showed significantly lower Shannon diversity in NEC (P = 0.026). The overall bacterial communities were also significantly different in NEC samples compared to SIP (P = 0.038), and large variability within NEC infants was observed. While no single OTU or genus was significantly associated with NEC or SIP, at the phylum level Proteobacteria (P = 0.045) and Bacteroidetes (P = 0.024) were significantly higher in NEC and SIP infants, respectively. CONCLUSIONS: Existing banks of intestinal FFPE blocks provide a robust and specific sample for profiling the microbiota at the site of disease. We showed preterm infants with NEC have lower diversity and different bacterial communities when compared to SIP controls.

Delayed Introduction of Parenteral Phosphorus Is Associated with Hypercalcemia in Extremely Preterm Infants.

BACKGROUND: Early parenteral nutrition (PN) provides essential macro- and micronutrients for extremely low birth weight (ELBW) infants <1000 g. Frequent cases of hypercalcemia [whole blood ionized calcium (iCa) > 1.45 mmol/L] in the first week of life while receiving PN solutions at our large quaternary center prompted investigation and 2 plan-do-study-act (PDSA) cycles to reduce rates of hypercalcemia. OBJECTIVE: We compared 2 cohorts of ELBW infants separated by PDSA cycles to evaluate and reduce the incidence of abnormal iCa concentration. METHODS: Data were recorded for 150 premature infants with mean birth weight of 726 ± 164 g, 48% male, and mean gestational age of 26 ± 2.1 wk. This process included an internal practice analysis and PDSA cycles monitored prospectively over 3 y. From December 2011 to September 2012, 66 infants received 0-1.2 mmol parenteral phosphorus supplementation/(kg ⋅ d) beginning at 72 h of life. In the second protocol, 84 infants born September 2012 to July 2013 received earlier phosphorus supplementation within 24 h of life. The peak whole blood iCa and serum phosphorus concentrations in the first week of life were monitored. RESULTS: Early introduction of phosphorus was significantly associated with a decreased mean peak iCa (1.64 ± 0.27 mmol/L to 1.50 ± 0.23 mmol/L, P = 0.001), and the incidence of severe hypercalcemia (iCa > 1.60 mmol/L) decreased from 50.0% to 21.4% (P = 0.002) in the first week of life. There was no difference in mortality, bronchopulmonary dysplasia, renal calcifications, seizures within 7 d of birth, brain calcifications, or intracranial hemorrhage between cohorts. CONCLUSION: Early introduction of phosphorus in PN solutions is associated with reduced incidence of whole blood iCa abnormalities in the first week of life and should be considered for ELBW infants. Ongoing evaluation of optimal mineral provision to this population after birth should be performed.

Randomized trial of human milk cream as a supplement to standard fortification of an exclusive human milk-based diet in infants 750-1250 g birth weight.

OBJECTIVE: To evaluate whether premature infants who received an exclusive human milk (HM)-based diet and a HM-derived cream supplement (cream) would have weight gain (g/kg/d) at least as good as infants receiving a standard feeding regimen (control). STUDY DESIGN: In a prospective noninferiority, randomized, unmasked study, infants with a birth weight 750-1250 g were randomly assigned to the control or cream group. The control group received mother's own milk or donor HM with donor HM-derived fortifier. The cream group received a HM-derived cream supplement if the energy density of the HM tested <20 kcal/oz using a near infrared HM analyzer. Infants were continued on the protocol until 36 weeks postmenstrual age. Primary outcomes included growth velocities and amount of donor HM-derived fortifier used. The hypothesis of noninferiority was established if the lower bound of the one-sided 95% CI for the difference in weight velocities exceeded -3 g/kg/day. RESULTS: There were no differences between groups in baseline demographics for the 78 infants studied except racial distribution (P = .02). The cream group (n = 39) had superior weight (14.0 ± 2.5 vs 12.4 ± 3.0 g/kg/d, P = .03) and length (1.03 ± 0.33 vs 0.83 ± 0.41 cm/wk, P = .02) velocity compared with the control group (n = 39). There were no significant differences in amount of fortifier used between study groups. The 1-sided 95% lower bound of the CI for the difference in mean velocity (cream-control) was 0.38 g/kg/d. CONCLUSIONS: Premature infants who received HM-derived cream to fortified HM had improved weight and length velocity compared with the control group. HM-derived cream should be considered an adjunctive supplement to an exclusive HM-based diet to improve growth rates in premature infants.

Factors associated with enteral autonomy after reanastomosis in infants with intestinal failure and ostomy: A descriptive cohort study.

BACKGROUND: To determine variables associated with outcomes in infants with intestinal failure (IF) and ostomy following reanastomosis (RA). METHODS: A single-center, descriptive cohort study of 120 infants with IF and a stoma from January 2011 to December 2020 with subsequent RA during initial hospitalization. The primary outcome was achievement of enteral autonomy (EA) following RA. Other outcomes were duration of hospital stay, and mortality. Penalized logistic regression and linear regression were used for data analysis. RESULTS: The median gestational age was 26 weeks, and the median birth weight was 890 g. Three infants died. The median duration between ostomy creation and RA was 80 days (interquartile range; 62.5, 100.5). For each additional day of discontinuity, the odds of EA decreased by 2% (odds ratio [OR] = 0.980; 95% confidence interval [CI]: 0.962, 0.999; P = 0.038), and death increased by 4.2% (OR = 1.042; 95% CI: 1.010, 1.075; P = 0.009). For each additional mL/kg/day of enteral feeds at RA, the odds of EA increased by 7.5% (OR = 1.075; 95% CI: 1.027, 1.126, P = 0.002) and duration of hospital stay decreased by 0.35 days (slope coefficient = -0.351; 95% CI: -0.540, -0.163; P < 0.001). CONCLUSION: Shorter duration of intestinal discontinuity and enteral nutrition before RA could positively influence EA and duration of stay in infants with IF and ostomy following RA.

Nutrition and the gut-brain axis in neonatal brain injury and development.

Early nutritional exposures, including during embryogenesis and the immediate postnatal period, affect offspring outcomes in both the short- and long-term. Alterations of these modifiable exposures shape the developing gut microbiome, intestinal development, and even neurodevelopmental outcomes. A gut-brain axis exists, and it is intricately connected to early life feeding and nutritional exposures. Here, we seek to discuss the (1) origins of the gut-brain access and relationship with neurodevelopment, (2) components of human milk (HM) beyond nutrition and their role in the developing newborn, and (3) clinical application of nutritional practices, including fluid management and feeding on the development of the gut-brain axis, and long-term neurodevelopmental outcomes. We conclude with a discussion on future directions and unanswered questions that are critical to provide further understanding and insight into how clinicians and healthcare providers can optimize early nutritional practices to ensure children not only survive, but thrive, free of neurodevelopmental impairment.

Dilemmas in feeding infants with intestinal failure: a neonatologist's perspective.

Intestinal failure in neonatal and pediatric populations can be debilitating for patients and difficult to manage for clinicians. Management strategies include referral to an intestinal rehabilitation center, small volume trophic feeds to stimulate the intestine with cautious advancement of enteral nutrition using a standardized and evidence-based feeding protocol, and supplemental parenteral nutrition to optimize an infant's growth and nutrition. In this review, we discuss the causes of intestinal failure, parenteral nutrition strategies, enteral feeding initiation and advancement protocols, as well as the challenges in feeding an infant with intestinal failure.

Dilemmas in human milk fortification.

Fortification of human milk is the standard of care for very low birth weight (VLBW) infants and is required to support adequate postnatal growth and development. Achieving adequate growth velocity and preventing growth faltering is critical for the developing neonatal brain and optimizing long-term neurodevelopmental outcomes. Mother's milk is the gold standard nutrition to feed preterm infants, however, it does not provide the nutrients needed to support the growth of VLBW infants. After the decision is made to use mother's milk (if available) or alternatively, donor human milk, many dilemmas exist with regards to additional treatment decisions surrounding the type of fortification to use, when to fortify, and the duration of fortification. In this article, we will review the differences in mother's milk compared to donor milk, the different types of human milk fortifiers, the optimal timing of fortification, and discuss when to discontinue human milk fortification.

A systematic review of associations between gut microbiota composition and growth failure in preterm neonates.

Growth failure is among the most prevalent and devastating consequences of prematurity. Up to half of all extremely preterm neonates struggle to grow despite modern nutrition practices. Although elegant preclinical models suggest causal roles for the gut microbiome, these insights have not yet translated into biomarkers that identify at-risk neonates or therapies that prevent or treat growth failure. This systematic review aims to identify features of the neonatal gut microbiota that are positively or negatively associated with early postnatal growth. We identified 860 articles, of which 14 were eligible for inclusion. No two studies used the same definitions of growth, ages at stool collection, and statistical methods linking microbiota to metadata. In all, 58 different taxa were associated with growth, with little consensus among studies. Two or more studies reported positive associations with Enterobacteriaceae, Bacteroides, Bifidobacterium, Enterococcus, and Veillonella, and negative associations with Citrobacter, Klebsiella, and Staphylococcus. Streptococcus was positively associated with growth in five studies and negatively associated with growth in three studies. To gain insight into how the various definitions of growth could impact results, we performed an exploratory secondary analysis of 245 longitudinally sampled preterm infant stools, linking microbiota composition to multiple clinically relevant definitions of neonatal growth. Within this cohort, every definition of growth was associated with a different combination of microbiota features. Together, these results suggest that the lack of consensus in defining neonatal growth may limit our capacity to detect consistent, meaningful clinical associations that could be leveraged into improved care for preterm neonates.

Early Fluid and Nutritional Management of Extremely Preterm Newborns During the Fetal-To-Neonatal Transition.

During the fetal-to-neonatal transitional period, extremely preterm newborns undergo significant intrabody fluid shifts and resulting weight loss due to increased insensible fluid losses due to immature skin, kidneys, among other factors. These ongoing physiologic changes make fluid and nutritional management complex in the neonatal-to-fetal transitional time period for extremely premature newborns. However, limited literature exists to guide optimal practices for providers caring for this population. Here, we review the evidence on optimal fluid and nutritional management during the fetal-to-neonatal transition of extremely preterm newborns.

Nutrition for Infants with Congenital Heart Disease.

Perioperative malnutrition in infants with congenital heart disease can lead to significant postnatal growth failure and poor short- and long-term outcomes. A standardized approach to nutrition is needed for the neonatal congenital heart disease population, taking into consideration the type of cardiac lesion, the preoperative and postoperative period, and prematurity. Early enteral feeding is beneficial and should be paired with parenteral nutrition to meet the fluid and nutrient needs of the infant.

Cholestasis impairs gut microbiota development and bile salt hydrolase activity in preterm neonates.

Cholestasis refers to impaired bile flow from the liver to the intestine. In neonates, cholestasis causes poor growth and may progress to liver failure and death. Normal bile flow requires an intact liver-gut-microbiome axis, whereby liver-derived primary bile acids are transformed into secondary bile acids. Microbial bile salt hydrolase (BSH) enzymes are responsible for the first step, deconjugating glycine- and taurine-conjugated primary bile acids. Cholestatic neonates often are treated with the potent choleretic bile acid ursodeoxycholic acid (UDCA), although interactions between UDCA, gut microbes, and other bile acids are poorly understood. To gain insight into how the liver-gut-microbiome axis develops in extreme prematurity and how cholestasis alters this maturation, we conducted a nested case-control study collecting 124 stool samples longitudinally from 24 preterm infants born at mean 27.2 ± 1.8 weeks gestation and 946 ± 249.6 g, half of whom developed physiologic cholestasis. Samples were analyzed by whole metagenomic sequencing, in vitro BSH enzyme activity assays optimized for low biomass fecal samples, and quantitative mass spectrometry to measure the bile acid metabolome. In extremely preterm neonates, acquisition of the secondary bile acid biosynthesis pathway and BSH genes carried by Clostridium perfringens are the most prominent features of early microbiome development. Cholestasis interrupts this developmental pattern. BSH gene abundance and enzyme activity are profoundly reduced in cholestatic neonates, resulting in decreased quantities of unconjugated bile acids. UDCA restores total fecal bile acid levels in cholestatic neonates, but this is due to a 522-fold increase in fecal UDCA. A majority of bile acids in early development are atypical positional and stereo-isomers of bile acids. We report novel associations linking isomeric bile acids and BSH activity to neonatal growth trajectories. These data highlight deconjugation of bile acids as a key microbial function that is acquired in early neonatal development and impaired by cholestasis.

Fatty acid concentrations in preterm infants fed the exclusive human milk diet: a prospective cohort study.

OBJECTIVE: Quantify blood fatty acids and growth outcomes in preterm infants fed the exclusive human milk diet. METHODS: A prospective cohort study of 30 infants 24-34 weeks gestation and ≤1250 g fed the exclusive human milk diet. Blood fatty acids were quantified at two time points. Comparisons were made using two-sample t-tests and Wilcoxon rank sum. RESULTS: Donor human milk-fed (n = 12) compared to mother's own milk-fed infants (n = 18) from birth to after 28 days of life, had an increased interval change of linoleic to docosahexaenoic acid ratio (5.5 vs. -1.1 mole percent ratio, p = 0.034). Docosahexaenoic and eicosapentaenoic acid interval changes were similar between groups. The arachidonic acid change was similar between groups (-2.3 vs. -0.9 mole percent, p = 0.37), however, both experienced a negative change across time. At 36 weeks postmenstrual age, growth velocities were similar for groups. CONCLUSION: An exclusive human milk diet maintains birth docosahexaenoic and eicosapentaenoic acid concentrations. However, the postnatal deficit in arachidonic acid was not prevented.

Probiotics and Human Milk Differentially Influence the Gut Microbiome and NEC Incidence in Preterm Pigs.

Necrotizing enterocolitis (NEC) is the leading cause of death caused by gastrointestinal disease in preterm infants. Major risk factors include prematurity, formula feeding, and gut microbial colonization. Microbes have been linked to NEC, yet there is no evidence of causal species, and select probiotics have been shown to reduce NEC incidence in infants. In this study, we evaluated the effect of the probiotic Bifidobacterium longum subsp. infantis (BL. infantis), alone and in combination with a human milk oligosaccharide (HMO)-sialylactose (3'SL)-on the microbiome, and the incidence of NEC in preterm piglets fed an infant formula diet. We studied 50 preterm piglets randomized between 5 treatments: (1) Preterm infant formula, (2) Donor human milk (DHM), (3) Infant formula + 3'SL, (4) Infant formula + BL. infantis, and (5) Infant formula and BL. infantis + 3'SL. NEC incidence and severity were assessed through the evaluation of tissue from all the segments of the GI tract. The gut microbiota composition was assessed both daily and terminally through 16S and whole-genome sequencing (WGS) of rectal stool samples and intestinal contents. Dietary BL. infantis and 3'SL supplementation had no effect, yet DHM significantly reduced the incidence of NEC. The abundance of BL. infantis in the gut contents negatively correlated with disease severity. Clostridium sensu stricto 1 and Clostridium perfringens were significantly more abundant in NEC and positively correlated with disease severity. Our results suggest that pre- and probiotics are not sufficient for protection from NEC in an exclusively formula-based diet. The results highlight the differences in microbial species positively associated with both diet and NEC incidence.