The potential physiological significance of milk-borne hormonally active substances for the neonate.
ABSTRACT This article reviews the presence and potential physiological significance of hormones and hormonally active substances (including growth factors) in human milk. Human milk has been found to contain several nonpeptide hormones and many peptide hormones and growth factors. In contrast to human breast milk, infant formulae lack some hormonally active peptides. There is little data concerning the effects of these agents on human neonates. Studies in immature experimental animals showing effects of orogastically administered hormones are summarized. The problems of supplementation of infant formula are discussed. Since hormones are present in the milk as a "cocktail" of potentially agonistic and antagonistic substances, one question is whether supplementation with a single agent would disturb this balance.
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ABSTRACT: Provision of an optimal environment for the calf is critical to establishing the patterns of growth and development essential to allow the heifer to express its genetic potential for milk output and reproductive capacity during its productive life. Maternal nutrition during gestation is now recognised as a key to genetic programming in utero and this influence is extended through the complexity of hormones, growth factors and immunostimulants incorporated into colostrum and milk consumed by the neonatal calf. This natural process is most often disrupted as calves are weaned abruptly to maximise milk output for commercial exploitation. The key then is to accelerate the rate of maturation of the ruminal epithelium through the provision of concentrate starter rations and high quality forage, which promote VFA production. Management systems to promote these processes in Holstein Friesian cattle are well developed, however, little is known of these processes with buffalo and Bos indicus dairy cattle such as the Sahiwal. The development of methods to program the neonate to grow faster to puberty in these species will be important to improving their productivity for the dairy industries in tropical and sub-tropical environments in the future.Asian Australasian Journal of Animal Sciences 05/2009; 22(5). · 0.64 Impact Factor
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ABSTRACT: Porcine colostrum and milk were separated into the acid-soluble and casein fractions by acidification followed by centrifuge. The acid-soluble fraction of porcine colostrum was further separated by liquid chromatography and anisotropic membrane filtration. Trypsin and chymotrypsin inhibitory capacity in porcine colostrum, milk and their components was determined by incubating bovine trypsin or chymotrypsin in a medium containing their corresponding substrates with or without addition of various amounts of porcine colostrum, porcine milk or their components. The inhibition of insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) degradation in pig small intestinal contents by porcine colostrum was measured by incubating iodinated IGF-I or EGF with the intestinal contents with or without addition of porcine colostrum. Degradation of labeled IGF-I or EGF was determined by monitoring the generation of radioactivity soluble in 30% trichloroacetic acid (TCA). The results showed that porcine colostrum had high levels of trypsin and chymotrypsin inhibitory activity and increased the stability of IGF-I and EGF in pig intestinal contents. The inhibitory activity declined rapidly during lactation. It was also found that trypsin and chymotrypsin inhibitory activity and the inhibition on IGF-I and EGF degradation in the acid-soluble fraction were higher than that in the casein fraction. Heat-resistance study indicated that trypsin inhibitors in porcine colostrum survived heat treatments of 100 water bath for up to 10 min, but exposure to boiling water bath for 30 min significantly decreased the inhibitory activity. Compared with the trypsin inhibitors, the chymotrypsin inhibitors were more heatsensitive. Separation of the acid-soluble fraction of porcine colostrum by liquid chromatography and anisotropic membrane filtration revealed that the trypsin and chymotrypsin inhibitory capacity was mainly due to a group of small proteins with molecular weight of 10,000-50,000. In conclusion, the present study confirmed the existence of high levels of protease inhibitors in porcine colostrum, and the inhibition of porcine colostrum on degradation of milk-borne growth factors in the pig small intestinal tract was demonstrated for the first time.Asian Australasian Journal of Animal Sciences 01/2003; 16(12). · 0.64 Impact Factor
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ABSTRACT: During early life, prolactin (PRL) ingested by the pups through the milk participates in the development of neuroendocrine, immunological and reproductive systems. The present study tested whether a deficiency in PRL in the dam's milk during early lactation affected the offspring in terms of the maternal responsiveness in the sensitization paradigm and behavioral response to a novel environment in the offspring. Thus, lactating rats were injected (sc) on postnatal days (PND) 2–5 with bromocriptine (125 μg/day), bromocriptine + ovine PRL (125 μg + 300 μg/day), or vehicle. As juveniles (at PND 24) or adults (PND 90–100), one female from each litter was exposed to 5 foster pups continuously for 8 days and their maternal responsiveness was recorded. Female offspring were also tested in an open field arena. Adult, but not juvenile, female offspring of bromocriptine-treated mothers showed an increased latency to become maternal, in comparison to latencies displayed by the offspring of control mothers. Furthermore, the proportion of adult, but not juvenile, offspring of bromocriptine-treated mothers that became maternal was lower than that showed by the offspring of vehicle-treated mothers. In comparison to female offspring of vehicle-treated mothers, female offspring of bromocriptine-treated mothers spent less time hovering over the pups (as juvenile females), body licking (as both juvenile and adult females), and in close proximity to pups (as adult females) during the maternal behavior test. Simultaneous administration of ovine PRL and bromocriptine reversed almost all the negative effects of bromocriptine. These data suggest that maternally-derived PRL participates during the early postnatal period in the development of neural systems that underlie the control of maternal behavior.Hormones and Behavior 09/2009; · 3.74 Impact Factor