The effect of oropharyngeal colostrum administration on the clinical outcomes of premature infants: A meta-analysis.

BACKGROUND: Preterm complications are now the second leading cause of death in children under five years of age. Colostrum is essential to prevent infection and promote maturation in preterm infants. Guidelines recommend that preterm infants be fed colostrum by the oral and pharyngeal routes as early as possible after birth to provide immune protection; however, due to disease and an uncoordinated sucking and swallowing function, it is challenging to provide colostrum through the oropharyngeal route, which limits the immune protection it provides. OBJECTIVE: To update the existing meta-analysis, evaluate the effect of oropharyngeal colostrum administration on related outcomes in preterm infants and explore the optimal frequency and duration of oropharyngeal colostrum administration through subgroup analysis. METHODS: The Cochrane Library, PubMed, Web of Science, ScienceDirect, and Ovid databases were searched for randomized control trials (RCTs) of oropharyngeal colostrum administration for preterm infants. Two researchers screened the literature strictly according to the inclusion and exclusion criteria and evaluated the quality. Primary data and data from the included literature were extracted. Finally, the data were statistically analyzed by the Review Manager 5.3 software. RESULTS: A total of 1736 preterm infants were included in 16 RCTs. The meta-analysis showed that the incidence of necrotizing enterocolitis, late-onset sepsis, feeding intolerance, and death was lower, the time to full enteral feeding was shorter, and the day of recovery to birth weight was earlier in the intervention group (oropharyngeal colostrum administration group) than in the control group, and this difference was statistically significant. Subgroup analysis: Frequency of oropharyngeal colostrum administration: The incidence of necrotizing enterocolitis and late-onset sepsis in the once every 4 h group was lower than that in the control group, and the time to complete enteral feeding was shorter. Duration of oropharyngeal colostrum administration: In the 1-3 days group and 4-7 days group, the time to full enteral feeding in the intervention group was shorter. In the 8-10 days group, the incidence of necrotizing enterocolitis and late-onset sepsis was lower in the intervention group. CONCLUSIONS: Oropharyngeal colostrum administration can reduce the incidence of necrotizing enterocolitis, late-onset sepsis, feeding intolerance and mortality, shorten the time to full enteral feeding, and lead to a faster recovery to birth weight in preterm infants. The appropriate oropharyngeal colostrum administration frequency may be 4 h, and the optimal duration may be 8-10 days. Therefore, it is recommended that clinical medical staff implement oropharyngeal colostrum administration for premature infants based on existing evidence. TWEETABLE ABSTRACT: Oropharyngeal colostrum administration can reduce the incidence of complications in preterm infants and shorten the time to full enteral feeding.

Genomic organization of the crested ibis MHC provides new insight into ancestral avian MHC structure.

The major histocompatibility complex (MHC) plays an important role in immune response. Avian MHCs are not well characterized, only reporting highly compact Galliformes MHCs and extensively fragmented zebra finch MHC. We report the first genomic structure of an endangered Pelecaniformes (crested ibis) MHC containing 54 genes in three regions spanning ~500 kb. In contrast to the loose BG (26 loci within 265 kb) and Class I (11 within 150) genomic structures, the Core Region is condensed (17 within 85). Furthermore, this Region exhibits a COL11A2 gene, followed by four tandem MHC class II αß dyads retaining two suites of anciently duplicated "αß" lineages. Thus, the crested ibis MHC structure is entirely different from the known avian MHC architectures but similar to that of mammalian MHCs, suggesting that the fundamental structure of ancestral avian class II MHCs should be "COL11A2-IIαß1-IIαß2." The gene structures, residue characteristics, and expression levels of the five class I genes reveal inter-locus functional divergence. However, phylogenetic analysis indicates that these five genes generate a well-supported intra-species clade, showing evidence for recent duplications. Our analyses suggest dramatic structural variation among avian MHC lineages, help elucidate avian MHC evolution, and provide a foundation for future conservation studies.

The first report of a Pelecaniformes defensin cluster: characterization of ß-defensin genes in the crested ibis based on BAC libraries.

Defensins play a key role in the innate immunity of various organisms. Detailed genomic studies of the defensin cluster have only been reported in a limited number of birds. Herein, we present the first characterization of defensins in a Pelecaniformes species, the crested ibis (Nipponia nippon), which is one of the most endangered birds in the world. We constructed bacterial artificial chromosome libraries, including a 4D-PCR library and a reverse-4D library, which provide at least 40 equivalents of this rare bird's genome. A cluster including 14 ß-defensin loci within 129 kb was assigned to chromosome 3 by FISH, and one gene duplication of AvBD1 was found. The ibis defensin genes are characterized by multiform gene organization ranging from two to four exons through extensive exon fusion. Splicing signal variations and alternative splice variants were also found. Comparative analysis of four bird species identified one common and multiple species-specific duplications, which might be associated with high GC content. Evolutionary analysis revealed birth-and-death mode and purifying selection for avian defensin evolution, resulting in different defensin gene numbers among bird species and functional conservation within orthologous genes, respectively. Additionally, we propose various directions for further research on genetic conservation in the crested ibis.