(1/161) Energy intake, not energy output, is a determinant of body size in infants.

BACKGROUND: It has been proposed that the primary determinants of body weight at 1 y of age are genetic background, as represented by parental obesity, and low total energy expenditure. OBJECTIVE: The objective was to determine the relative contributions of genetic background and energy intake and expenditure as determinants of body weight at 1 y of age. DESIGN: Forty infants of obese and 38 infants of lean mothers, half boys and half girls, were assessed at 3 mo of age for 10 risk factors for obesity: sex, risk group (obese or nonobese mothers), maternal and paternal body mass index, body weight, feeding mode (breast, bottle, or both), 3-d energy intake, nutritive sucking behavior during a test meal, total energy expenditure, sleeping energy expenditure, and interactions among them. RESULTS: The only difference between risk groups at baseline was that the high-risk group sucked more vigorously during the test meal. Four measures accounted for 62% of the variability in weight at 12 mo: 3-mo weight (41%, P = 0.0001), nutritive sucking behavior (9%, P = 0.0002), 3-d food intake (8%, P = 0.0002), and male sex (3%, P = 0.05). Food intake and sucking behavior at 3 mo accounted for similar amounts of variability in weight-for-length, body fat, fat-free mass, and skinfold thickness at 12 mo. Contrary to expectations, neither total nor sleeping energy expenditure at 3 mo nor maternal obesity contributed to measures of body size at 12 mo. CONCLUSIONS: Energy intake contributes significantly to measures of body weight and composition at 1 y of age; parental obesity and energy expenditure do not.  (+info)

(2/161) Milk intake of suckling kittens remains relatively constant from one to four weeks of age.

The daily milk intake of 14 domestic short-haired kittens (Felis catus) from five litters was estimated during wk 1-4 postpartum using the isotope dilution technique. Kittens received a single intraperitoneal injection of tritiated water, and blood samples were obtained from the jugular vein for radioactivity measurements at 2 and 96 h after injection. One kitten in each litter was used as a control to allow calculation of recycling of tritiated water. The mean (+/- SEM) biological half-life of tritiated water in the kittens increased from 2.4 +/- 0.1 d in wk 1 to 4.9 +/- 0.2 d in wk 4 postpartum. Recycling of tritiated water accounted for (mean +/- SEM) 5.9 +/- 0.8, 12.0 +/- 0.5, 7.7 +/- 1.3 and 10.0 +/- 1.3% of the kittens' daily water intake during postnatal wk 1-4, respectively. Daily milk intake of the kittens during wk 1-4 postpartum was 47.3 +/- 0.8, 47.4 +/- 1.5, 48.7 +/- 1.6 and 43.7 +/- 2.0 g, respectively. There was no effect of gender on milk intake. The daily metabolizable energy requirement of suckling kittens, estimated by multiple regression analysis, was 356 kJ/kg(0.75), whereas the metabolizable energy required per gram of gain was estimated to be 7. 8 kJ/d. The milk intake of suckling kittens remained relatively constant throughout the first 4 wk of lactation, and during this period, they seemed to have a lower energy requirement for maintenance.  (+info)

(3/161) Role of mother-young interactions in the survival of offspring in domestic mammals.

The defining characteristic of mammals is that females nurse and care for their young; without this, the neonate has no chance to survive. Studies on wild and domestic species show that the neonatal period is the most critical step in the lifetime of a mammal. This review compares three well-studied species (the rabbit, pig and sheep) that differ in their parental strategies and in the problems that neonates have to overcome. As a general trend, mother-young interactions vary according to the maturity of the newborn, and the size of the litter. Neonatal survival relies to a great extent on an environment that is ecologically appropriate for the developmental stage of the neonate, and on optimum interactions with the mother. Adaptive maternal care supposes that the mother provides the basic needs of the neonate: warmth (in pigs and rabbits) or shelter, food, water and immunological protection (via colostrum) and, in some instances, protection from predators and other conspecifics. A major risk facing all neonates, other than the birth process itself, is inadequate colostrum intake owing to delayed suckling or competition with siblings, which leads to starvation, hypothermia or even crushing, as has been observed in pigs.  (+info)

(4/161) Requirement for the lpA1 lysophosphatidic acid receptor gene in normal suckling behavior.

Although extracellular application of lysophosphatidic acid (LPA) has been extensively documented to produce a variety of cellular responses through a family of specific G protein-coupled receptors, the in vivo organismal role of LPA signaling remains largely unknown. The first identified LPA receptor gene, lp(A1)/vzg-1/edg-2, was previously shown to have remarkably enriched embryonic expression in the cerebral cortex and dorsal olfactory bulb and postnatal expression in myelinating glia including Schwann cells. Here, we show that targeted deletion of lp(A1) results in approximately 50% neonatal lethality, impaired suckling in neonatal pups, and loss of LPA responsivity in embryonic cerebral cortical neuroblasts with survivors showing reduced size, craniofacial dysmorphism, and increased apoptosis in sciatic nerve Schwann cells. The suckling defect was responsible for the death among lp(A1)((-/-)) neonates and the stunted growth of survivors. Impaired suckling behavior was attributable to defective olfaction, which is likely related to developmental abnormalities in olfactory bulb and/or cerebral cortex. Our results provide evidence that endogenous lysophospholipid signaling requires an lp receptor gene and indicate that LPA signaling through the LP(A1) receptor is required for normal development of an inborn, neonatal behavior.  (+info)

(5/161) Belly-nosing in early-weaned piglets is not influenced by diet quality or the presence of milk in the diet.

Early weaning of piglets can lead to an increase in belly-nosing and other oral-nasal behavior (nosing, chewing, or sucking other piglets), but the causative factors involved in these behavior patterns are largely unknown. Because these behavior patterns resemble massaging the udder and sucking, they may be associated with feeding. The objectives of this study were to determine any effect of diet quality or the presence of milk in the diet on belly-nosing behavior of piglets weaned at 14 to 18 d. During the first 2 wk after weaning, piglets were fed diets differing in quality and inclusion of milk products. Six replicates of eight piglets per replicate, blocked by initial body weight, (n = 192) were offered one of four dietary treatments: HQM: high quality, high in milk products; HQ: high quality, no milk products; PQ: poor quality, no milk products; HQ+MR: high quality, no milk products (as HQ) sprayed with milk replacer five times daily. Thereafter, the piglets were fed a standard nursery diet. Feed intake was measured daily for wk 1 and again at the end of wk 2. Behavior was recorded every 5 min during two 4-h periods on d 2 to 7, 10, 14, 17 and 21 after weaning. Dietary treatment influenced ADFI and ADG during wk 1. Average daily feed intake (P < 0.05) and ADG (P < 0.05) of piglets on PQ were less than those of piglets on the other treatments. During wk 2, ADFI (P > 0.10) and ADG (P > 0.10) were the same across all treatments. Overall, ADFI was not influenced by the inclusion of milk products in the diet or the addition of milk replacer (P > 0.10); however, ADG was. Piglets on HQM had higher ADG than those on HQ during wk 2 (P < 0.05) and 3 after weaning (P < 0.05). However, milk replacer did not influence ADG (P > 0.10). Although the dietary treatments did affect ADFI and ADG, there were no effects on any behavior pattern recorded, including time spent at the feeder (P > 0.10). Lower weight-for-age piglets performed more oral-nasal behavior, in total, than higher weight-for-age piglets (P < 0.03). Neither feeding a poor-quality diet nor the presence of milk in the diet had an effect on belly-nosing or other oral-nasal behavior patterns during the first 3 wk after weaning. Belly-nosing does not seem to be associated with feeding.  (+info)

(6/161) Histological study of masseter muscle in a mouse muscular dystrophy model (mdx mouse).

Histological changes in the masseter muscle were observed over time in mdx mice, a muscular dystrophy model. It was found that marked necrosis occurs about the time of weaning at around 4 weeks of age; then the tissue actively regenerates at 8 weeks and stabilizes as regenerated muscle with centronuclei at 15 weeks old. This study examined the centronucleus in regenerated muscle. The process from necrosis to regeneration in muscle fibers occurs a little later in the masseter muscle than in other limbic muscles. Regenerated muscles observed around 15 weeks after birth showed a moth-eaten appearance. Transmission Electron Microscope (TEM) observation of transverse sections of muscle fibers revealed that myofibrils surrounded lost regions in the area showing a moth-eaten appearance. Thus, some defensive mechanism may affect the ability of muscle fibers to maintain a function close to normal in mdx mice even though the muscle fibers develop muscular dystrophy. The function of the masseter muscle drastically changes from sucking to mastication behavior at around 4 weeks, and this was considered to influence the morphological changes in the muscle tissue. The moth-eaten appearance seen at 15 weeks may represent an appropriate myofibril reconstruction preventing invasion of the lost regions.  (+info)

(7/161) Induction and inhibition of implantation in lactating rats.

The interrelationship between prolactin and LH in the maintenance of pregnancy during lactation was studied. The reduction of suckled young from eight to two or less, as late as on the morning of Day 4 of pregnancy, resulted in normal implantation. Reintroduction of eight young on Day 4 to lactating pregnant rats deprived of their litters on Day 1 resulted in an inhibition of implantation, but reintroduction on Days 5 or 6 did not inhibit implantation. If oestrogen, HCG or PMSG was given on Day 4 of pregnancy, implantation was induced at the normal time in rats suckling large litters. When LH antiserum was given on the morning of Day 4 or Day 8 to pregnant rats suckling two young each, it blocked implantation and postimplantation survival of blasto-cysts, respectively. When the number of suckling young was increased from two to eight on Day 6, however, LH antiserum blocked pregnancy only to the extent of 70%. Prolactin administered during the preimplantation phase inhibited implantation in pregnant rats suckling a minimum number of young, but had no effect when given during the postimplantation phase. Progesterone failed to block implantation. Prolactin had no inhibitory effect on implantation in the absence of the suckling stimulus or in non-lactating pregnant rats. The inhibition of implantation by prolactin in rats suckling two young could be effectively reversed by the administration of oestrogen, PMSG or HCG on Day 4 of pregnancy.  (+info)

(8/161) Initial management of breastfeeding.

Breast milk is widely accepted as the ideal source of nutrition for infants. In order to ensure success in breastfeeding, it is important that it be initiated as early as possible during the neonatal period. This is facilitated by skin-to-skin contact between the mother and infant immediately following birth. When possible, the infant should be allowed to root and latch on spontaneously within the first hour of life. Many common nursery routines such as weighing the infant, administration of vitamin K and application of ocular antibiotics can be safely delayed until after the initial breastfeeding. Postpartum care practices that improve breastfeeding rates include rooming-in, anticipatory guidance about breastfeeding problems and the avoidance of formula supplementation and pacifiers.  (+info)