The purpose of this study is to explore the effects of Oropharyngeal administration of colostrum to very low birth weight infants on sIgA and lactoferrin, in order to explore the protect immune function of colostrum to very low birth weight infants, to improve the utilization of breast milk and reduce infection rates of very low birth weight infants.

The number of very low born weight infants increased every year.they are suffer from many questions.Recent studies have shown that Oropharyngeal administration of colostrum to very low birth weight infants can reduce the time reach full enteral nutrition .But there are no evidence support that it can promote infants' immune response. The hypothesis of the current study is that Oropharyngeal administration of colostrum to very low birth weight infants may increase the secretion of sIgA in urine and saliva.

The current study adopts randomized, double blind, controlled intervention trial, gives Oropharyngeal administration of colostrums to very low birth weight infants in intervention group and Oropharyngeal administration of Normal saline to control group. All indicators in this study are discrete traits, for sIgA、Lactoferrin number in Saliva and urine， number of CRP，time Begin oral feeding，time up to full enteral feeding， Person's chi-square tests were used for comparisons. For Blood culture results，The number of necrotizing enterocolitis (NEC) occurred， the investigators use Chi-square tests for comparisons between two groups. The study expects that Oropharyngeal administration of colostrum to very low birth weight infants can increase the secretion of sIgA in urine and saliva.

Inclusion Criteria:

1. Born weight≤1500g
2. transferred to our hospital within 24 hours after birth
3. the mother can provide colostrum
4. parents of the infants agreed to participate in this study

Exclusion Criteria:

1. The infants suffering from life-threatening conditions ,such as severe heart disease,whose survival time are expected <30d

2. The infants suffering from any kinds of disease,which impact they take human milk by mouth.(such as gastrointestinal malformations, NEC, etc.）

3. human milk is contraindicated

   • An infant whose mother :

     • Is infected with the human immunodeficiency virus (HIV)
     • Is taking antiretroviral medications
     • Has untreated active tuberculosis
     • Is infected with human T-cell lymphotropic virus type l or ll
     • Is using or dependent on an illicit drug except if the breastmilk is medically indicated
     • Is taking prescribed cancer chemotherapy agents contraindicated for breastfeeding
     • Is receiving any medications contraindicated in breast feeding
     • Is receiving diagnostic or therapeutic radioactive isotopes or exposure to radioactive materials (for as long as they are radioactive in the milk)

   • An infant diagnosed with galactosemia, a rare genetic metabolic disorder