Colostrum importance

S irenians are characterized by hemochorial placentation, a model which favors a more important role for transplacental transfer of immunoglobulins, and less via colostrum. 

Studies in human adults using radioisotopes or stable isotopes of Zn showed that Zn absorption is higher from human milk (41 percent) than from cow (28 percent) or soy formulas (14 percent) [77]. In any case, it seems that there is no need to fortify cow-based formulas with Zn, since cow milk contains much more Zn than breast milk [77]. However, Zn bioavailavility from breast milk is clearly higher than from formulas, which indicates a different composition in Zn species. Experiments in speciation of Zn in formula milk whey carried out by SEC showed that Zn was mostly found in the LMW (< 10 kDa) fraction, as a complex of citrate and only a small fraction of the metal was bound to whey proteins (435 kDa) [15, 18, 21]. Although such species are detected in human milk, important differences have been found between the distribution patterns of Zn in breast milk and in cow-based formula milks (see Fig. 17.11 and compare with Fig. 17.4). The levels of Zn in formulas are higher than in human milk and in colostrums [18]. 

Because of this wide range in concentration, the complex protein composition of milk, and the even greater complexity of colostrum, considerable care must be exercised in the isolation of a-lactalbumin (indeed, the same may be said of the isolation of lysozyme from these secretions). Furthermore, if the study of the isolated protein is to include conformation and/or studies of enzymatic (and immunological) activity, considerable care must be taken that the method of isolation does not alter the conformation or interfere with the activity. This is particularly important in determining whether or not the isolated protein has a-lactalbu-... 

Catalase activity is important in milk and milk products analyses. Since normal milk has no significant amount of catalase, catalase activity indicates the presence of leucocytes caused by disorders or diseases of the udder, of colostrum in the milk, or of bacterial contamination. 

A possibly more important form of IgA is called secretory IgA, found in tears, sweat, saliva, milk, colostrum, and gastrointestinal and bronchial secretions. Secretory IgA has a molecular weight of 380 kDa and consists of two molecules of IgA, a secretory component (MW 70 kDa), and a J chain (15.6kDa). It is synthesized mainly by plasma cells in the mucous membranes of the gut and bronchi and in the ductules of the lactating breast. The secretory component makes secretory IgA more resistant to enzymes, allowing it to protect the mucosa from bacteria and viruses. Its presence in colostrum and milk probably aids in protection of neonates from intestinal infections. IgA can activate complement by the alternative pathway (see Figure 20-7), but the exact role of IgA in serum is not clear. 

IgG is involved in secondary response, placental transfer, and complement fixation. IgA is important for the immune response in respiratory and gastrointestinal tracts, body surfaces, colostrum, and isohemagglutinins. IgM is produced in primary response and in response to T-independent antigens. IgM is also a powerful agglutinin and is important for complement fixation. IgD is an early membrane receptor on lymphocytes. IgE plays a role in allergic responses. 

SC has at least two important functions (i) it transports the secretory IgA (sIgA) through the epithelium to the lumen, and (ii) it confers a greater resistance of the sIgA in the mucous secretions or colostrum against proteolytic attack. Sometimes, IgM with SC is found in patients with an IgA deficiency. 

IgA constitutes 5-20% of the Ig in normal sera, and is primarily monomeric in serum. The most important form of IgA, the dimeric secretory form, is predominant in seromucous secretions (colostrum, tears, saliva, perspiration, sputum, feces, and vaginal and seminal fluid). 

The preponderance of B. bifidum in the faeces of breast-fed infants is due to the presence of stimulatory factors in human milk. The most important of these are N-acetylglucosamine-containing saccharides, referred to as bifidus factor I, which is present at high levels in human milk and colostrum and bovine colostrum but at very low concentrations in the milk of cows, goats and sheep. Human milk also contains several non-dialysable bifidus-promoting factors which are glycoproteins, referred to as bifidus factor II. Many of the glycoproteins have been isolated and characterized (see Fox and Flynn, 1992). 

A similar reaction had previously been observed by McGuire and coworkers in an investigation of D-galactosyl transferase in bovine colostrum and in a particulate fraction of rat tissues this enzyme is believed to play an important role in the biosynthesis of carbohy-... 

Like vitamin A, it was thought that the transfer of vitamin E across the placenta was limited, with the neonate relying on colostrum to meet its requirements. More recent evidence in sheep indicates that placental transfer does occur, with increased muscle and brain concentrations in lambs born from ewes fed higher levels. Nonetheless, colostrum is a very important source of vitamin E for the new born. 

A third method of absorption is by pinocytosis cell drinking , in which cells have the capacity to engulf large molecules in solution or suspension. Such a process is particularly important in many newborn suckled mammals in which immunoglobulins present in colostrum are absorbed intact. 

Human colostrum and milk contain other substances important to the infant, for example the iron-binding protein lactoferrin and the enzyme lysozyme, both of which, like IgA, prevent infection within the digestive tract. It is going to be difficult for manufacturers of infant foods to include these substances in their products, and it seems important that all infants should have the benefits of colostrum and breast milk, even if only for a short time. 

In order to use your procedure, that is the TSH values obtained from the screening of congenital hypothyroidism, how important is it to standardize the conditions For instance, does the variability of iodine in human colostrum play a role Is there a difference in relation to the time of initiation of breastfeeding Is it different if the newborn gets its iodine supplement from maternal milk or from formula milk How do you control for the differences in the iodine content of formula milk, since we saw during this meeting that 100 % differences may be found between various types of formula milk. 

Tissue surveys revealed the widespread presence of an enzyme which would transfer sialic acid from CMP-sialic acid to lactose. The enzyme was found in rat spleen, testes, kidney, lung, brain, and liver. More importantly, this work led investigators to look at milk and colostrum as sources of the glycosyltransferases. These secretions turned out to contain large amounts of soluble glycosyltransferases—a great boon. 

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