<prompt> Most common immunoglobulin secreted by mother in milk and colostrum is :IgAIgGIgEIgD  <response>: Ans. is a i.e. IgA Composition of Breast Milk : Carbohydrate - Lactose is present in high concentration in breast milk. Protein content is low, as the baby cannot metabolise a high protein diet. The proteins are mainly lactalbumin and lactoglobulin, which are easily digestible. It is also rich in the aminoacids taurine and cysteine, which are necessary for neurotransmission and neuromodulation. Fats - Breast milk is rich in polyunsaturated fatty acids PUFA needed for myelination. Water and electrolytes - The water content is 86 - 87. Immunological superiority - Breast milk contains immunoglobulins, especially IgA and IgM, iysozyme, lactoferrin which protects against enterobacteria, bifidus factor to protect against E.coli, PABA which protects from malaria. Breast milk has a high concentration of secretory IgA, 1gM. Colostrum -Contains antibody 1gA produce locally. Therefore, IgA is the option of choice. 