Effect of short-term fasting/refeeding on epidermal growth factor content in the gastrointestinal tract of suckling rats.

Epidermal growth factor (EGF) is trophic for varying regions of the developing gastrointestinal tract (GIT) of suckling rats. The presence of large amounts of EGF in milk from various species, combined with low production of EGF by suckling animals, led to speculation that milk is a major source of EGF for suckling rats. We report that short-term fasting (8 hr) of 12-day-old suckling rats resulted in a significant decrease in the levels of immunoreactive EGF (irEGF) in the GIT. Pups refed by lactating mothers for 1 to 4 hr exhibited an increase in irEGF to original levels, whereas pups fed a rat milk substitute by gastric gavage did not have an increase in irEGF content. The irEGF levels in the GIT of pups that were manually fed normal rat milk, or rat milk substitute supplemented with EGF, returned to the prefasted levels. Fasted suckling rats refed 2 ml of rat milk in 2 h exhibited significantly higher level of irEGF in the GIT than did those refed with 0.5 ml in 45 min. Since rat milk irEGF exists in three distinct forms (A, B, and C; C is equal to authentic submandibular gland EGF, the irEGF forms in the GIT were characterized by native polyacrylamide gel electrophoresis. In the stomach luminal contents of the fed suckling rats, only the larger form, Peak B, was observed. Both the luminal content and the mucosa scrapings of all other segments of all groups contained only Form D (comigrating with desarginyl EGF), a metabolic derivative of EGF. All forms were immunoreactive, exhibited receptor binding, and stimulated DNA synthesis in growth-arrested fibroblasts. The rapid changes in EGF within the GIT of suckling rats suggest the EGF can acutely modify some GIT functions of suckling rats.     

Selenium content of Spanish infant formulae and human milk: Influence of protein matrix, interactions with other trace elements and estimation of dietary intake by infants

The selenium content of infant formulae varies as a result of differences in the amount of intrinsic selenium compounds. Manufacturers have been gradually changing the protein profile of infant formulae to reflect human milk contents more closely. Because of these variations in infant formula composition and their potential impact on selenium content, this trace element was analysed with regard to the different protein sources.

The aims of this study were to determine the selenium content in infant formulae sold commercially in Spain, to estimate a daily dietary intake for infants fed on formulae and to compare with the selenium provided by Spanish breast milk samples used as a reference. We have also identified certain trace elements added to formulae which interact with selenium according to the type and protein matrix of the infant formulae.

Selenium concentration was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with a hydride generator.

The selenium concentrations in human milk and infant formulae determined in this study are similar to those found by other researchers in different countries. The daily selenium intake from the formulae studied was estimated according to the recommended doses from the manufacturers. The theoretical selenium intake of nursed infants has been studied in relation to the Recommended Dietary Allowance (RDA: 10 μg Se/day) and the specific recommendations for infant formula nutrient contents (10–35 μg Se/L) set by the Expert Panel of Life Sciences Research Office (LSRO) of the American Society for Nutritional Sciences.

According to our results, on an overall view, infants fed on the studied infant formulae have an intake between basal and normative requirements. This might be considered as providing an adequate selenium supply. However, the intake of selenium provided by several formulae included in this research did not reach the RDA for the first month of neonate life.     

Stimulatory effects of epidermal growth factor on deoxyribonucleic acid synthesis in the gastrointestinal tract of the suckling mouse

The effects of epidermal growth factor (EGF), cortisone and thyroxine on deoxyribonucleic acid (DNA) synthesis in the esophagus, stomach, small intestine and colon have been studied in suckling mouse. Daily administration of EGF [4 micrograms/g body weight (bw)/day] during 3 days to 8-day-old mice induced a significant increase of the incorporation of [3H]thymidine into DNA in the stomach, the small intestine, and the two halves of the colon. The DNA synthesis in the esophagus remained unaffected by the EGF treatment. The maximal increase of [3H]thymidine incorporation into DNA was observed in the colon, and represented 112%. Daily administration of cortisone acetate (25 micrograms/g bw/day) or thyroxine (1 microgram/g bw/day) during 3 days to 8-day-old mice had no significant influence of the DNA synthesis of any part of the gastrointestinal tract. These results show that EGF is able to affect the DNA synthesis in the stomach, small intestine and colon of suckling mice.     

Performance of dairy ewes fed diets with a fibrolytic enzyme product included in the concentrate during the suckling period

Seventy-two multiparous ewes from two dairy breeds (Manchega, n = 36 and Lacaune, n = 36) were used in a replicated 2 × 2 factorial design to evaluate the effects of diet supplementation with an exogenous fibrolytic enzyme product on lactation performance and feed intake during the suckling period (weeks 1 to 4) according to breed. Ewes were blocked in groups of nine and fed ad libitum after lambing a diet based on 70% forage and 30% concentrate to which the enzyme was added after pelleting. Experimental concentrates were: control (without enzyme) and enzyme (fibrolytic enzyme complex, included at 0.47% volume to weight of concentrate). Twenty-four dry and open ewes (Manchega, n = 12 and Lacaune, n = 12) were also grouped by breed and used to measure the fill value of the ration used. During the suckling period, milk yield, milk composition, dry matter intake, lamb growth, as well as body weight change and body condition score change were not affected by enzyme supplementation. Breed effect was significant for milk yield, the Manchega ewes yielding less milk with a higher content of milk components than the Lacaune ewes. The opposite was observed for dry matter intake. Enzyme supplementation reduced intake by 9% in the dry ewes, resulting in a greater fill value of the diet. In conclusion, no lactational effects were detected when the fibrolytic enzyme product was added to the concentrate fed to dairy ewes.     

Milk intake and carbon dioxide production of piglets determined with the doubly labelled water technique

The present study was undertaken to study different methodological aspects of quantifying CO2 production and milk intake of suckling piglets using the doubly labelled water (DLW) technique. In total, 37 piglets were enriched intraperitoneally with DLW to study equilibration time of 18O (n = 3), to validate the estimation of milk intake and CO2 production (n = 10) of piglets fed milk replacer and to quantify milk intake and CO2 production of piglets nursed ordinarily by sows (n = 24). Enrichment of 18O in expired air was analysed without any sample preparation, whereas enrichment of 18O in serum was analysed after a minimum step of sample preparation, which included pipetting of the sample, blowing gaseous CO2 into the vial for 3 s and equilibrating for 24 h. The 18O enrichment of CO2 in expired air was constant within 30-40 min of intraperitoneal injection, suggesting that DLW was equilibrated within the body water by that time. For piglets fed milk replacer, the estimation of the daily CO2 production by the DLW method (64.0 ± 2.7 l CO2/day) was in agreement with that obtained by respiration trials (64.7 ± 1.8 l CO2/day). Furthermore, the intake of milk replacer (891 ± 63 g/day) determined by deuterium oxide (D2O) dilution was similar in magnitude to that found by weighing the milk disappearance (910 ± 58 g/day). The milk intake of piglets fed milk replacer was comparable with that of sucking piglets, but sucking piglets had a remarkably higher CO2 production than artificially reared piglets, which likely was caused by a higher intake of milk solids and a higher activity level. For sucking piglets, the daily CO2 production increased curvilinearly with increasing live weight (LW) in kg: piglet CO2 production (l/day) = 25.75 × LW - 1.01 × LW2. In conclusion, 18O equilibrates fast within the body water pool when administered intraperitoneally, and the accuracy of assessing milk intake and rate of CO2 production using the DLW technique is promising. Assessment of excess enrichment of 18O in serum proved to be robust. Finally, the CO2 production of piglets fed milk replacer differs considerably from that of sucking piglets.     

Utilization of milk energy by suckling mink kits

A total of 36 mink dams and their litters of 3, 6 or 9 kits were used for determination of milk intake of the suckling young by means of deuterium dilution technique, and chemical composition of milk and of kit bodies. Measurements were performed during lactation weeks 1-4, each week with 3 dams with each litter size. Milk intake was determined over a 48 h measurement period, and by the end of this milk samples were collected and 2 kits (litters of 6 and 9) or 1 kit per litter (litters of 3) were killed for body chemical composition. Based on the results, different models were applied for calculation of the energetic efficiency of milk. Dam milk yield increased steadily from week 1 until week 3 but only slightly from week 3 to 4. The increase declined with increasing litter size, and for dams suckling 9 kits the increment from week 3 to week 4 was only 2 g. The dry matter content of milk increased significantly as lactation progressed, being reflected in crude protein increasing from 6.9% in lactation week 1 to 8.1% in week 4. Milk fat increased concomitantly from 5.6% to 8.0%. In kit bodies, crude protein content increased from 9.4% in week 1 to about 12% in weeks 3 and 4. Body fat content increased from week 1 (4.1%) to week 3 (8.4%) and then declined in week 4 (7.1%). Animals suckled in litters of 3 kits had the highest milk intake and live weight and kits suckled in litters of 9 had the lowest milk intake, live weight and daily gain. In terms of milk intake per g gain kits in litters of 6 were the most efficient, with 4.1 g milk per g body gain. The metabolizable energy requirement for maintenance (MEm) was estimated to 448 kJ/kg(0.75 and the efficiency of utilization of ME for body gain (kg) to 0.67, the estimates being higher (MEm) or in good agreement with previous findings (kg) in suckling mink kits.     

Utilization of milk energy by suckling mink kits

A total of 36 mink dams and their litters of 3, 6 or 9 kits were used for determination of milk intake of the suckling young by means of deuterium dilution technique, and chemical composition of milk and of kit bodies. Measurements were performed during lactation weeks 1?–?4, each week with 3 dams with each litter size. Milk intake was determined over a 48?h measurement period, and by the end of this milk samples were collected and 2 kits (litters of 6 and 9) or 1 kit per litter (litters of 3) were killed for body chemical composition. Based on the results, different models were applied for calculation of the energetic efficiency of milk. Dam milk yield increased steadily from week 1 until week 3 but only slightly from week 3 to 4. The increase declined with increasing litter size, and for dams suckling 9 kits the increment from week 3 to week 4 was only 2?g. The dry matter content of milk increased significantly as lactation progressed, being reflected in crude protein increasing from 6.9% in lactation week 1 to 8.1% in week 4. Milk fat increased concomitantly from 5.6% to 8.0%. In kit bodies, crude protein content increased from 9.4% in week 1 to about 12% in weeks 3 and 4. Body fat content increased from week 1 (4.1%) to week 3 (8.4%) and then declined in week 4 (7.1%). Animals suckled in litters of 3 kits had the highest milk intake and live weight and kits suckled in litters of 9 had the lowest milk intake, live weight and daily gain. In terms of milk intake per g gain kits in litters of 6 were the most efficient, with 4.1?g milk per g body gain. The metabolizable energy requirement for maintenance (MEm) was estimated to 448 kJ/kg^0.75 and the efficiency of utilization of ME for body gain (k_g) to 0.67, the estimates being higher (MEm) or in good agreement with previous findings (k_g) in suckling mink kits.     

Hypothalamus integrity and appetite regulation in low birth weight rats reared artificially on a high-protein milk formula

High-protein (HP) milk formulas are routinely used in infants born with a low birth weight (LBW) to enhance growth and ensure a better verbal IQ development. Indirect evidence points to a link between an HP intake during early life and the prevalence of obesity in later life. We hypothesized that HP milk supplementation to LBW pups during early postnatal life would impact hypothalamic appetite neuronal pathways development with consequences, at adulthood, on energy homeostasis regulation. Rat pups born with a LBW were equipped with gastrostomy tubes on the fifth day of life. They received a milk formula with either normal protein (NP, 8.7 g protein/dl) or high protein content (HP; 13.0 g protein/dl) and were subsequently weaned to a standard, solid diet at postnatal day 21. Rats that had been fed HP content milk gained more weight at adulthood associated with an increase of plasma insulin, leptin and triglycerides concentrations compared to NP rats. Screening performed on hypothalamus in development from the two groups of rats identified higher gene expression for cell proliferation and neurotrophin markers in HP rats. Despite these molecular differences, appetite neuronal projections emanating from the arcuate nucleus did not differ between the groups. Concerning feeding behavior at adulthood, rats that had been fed HP or NP milk exhibited differences in the satiety period, resting postprandial duration and nocturnal meal pattern. The consequences of HP milk supplementation after LBW will be discussed in regard to neural development and metabolic anomalies.     

Lipogenic potential in liver of the preweanling rat: influence of dietary cholesterol

We examined the effect of a lower dietary cholesterol load on hepatic lipogenic capacity and plasma cholesterol concentrations during the normal suckling period in artificially reared preweanling rats. The artificially reared rats were fed a milk formula that contained low or normal concentrations of cholesterol during the period from the 5th to 17th day after birth. The activities of HMG-CoA synthase and HMG-CoA reductase in livers of 17-day-old rat pups reared on the low-cholesterol diet were enhanced three- to five-fold over those observed in the age-matched rats in the normal cholesterol and mother-reared control groups. The concentration of cholesterol in plasma of rats reared on the low-cholesterol milk was about 20% lower than that for mother-reared controls. In contrast, rats reared on milk with normal cholesterol content exhibited plasma cholesterol levels about 25 and 50% higher than the mother-reared and low cholesterol groups, respectively. The long-term metabolic consequences of rearing rats on milk formulations without adequate cholesterol remains to be determined.     

Estimating daily intakes of manganese due to breast milk,infant formulas,or young child nutritional beverages in the United States and France: Comparison to sufficiency and toxicity thresholds

BackgroundAlthough manganese (Mn) is an essential nutrient, recent research has revealed that excess Mn in early childhood may have adverse effects on neurodevelopment.MethodsWe estimated daily total Mn intake due to breast milk at average body weights by reviewing reported concentrations of breast milk Mn and measurements of body weight and breast milk intake at 3 weeks, 4.25 months, 7 months, and 18 months. We compared these figures to the Mn content measured in 44 infant, follow-up, and toddler formulas purchased in the United States and France. We calculated Mn content of formula products made with ultra-trace elemental analysis grade water (0 μg Mn/L) and with water containing 250 μg Mn/L, a concentration which is relatively high but less than the World Health Organization Health-based value of 400 μg Mn/L or the United States Environmental Protection Agency Health Advisory of 350 μg Mn/L.ResultsEstimated mean daily Mn intake from breast milk ranged from 1.2 μg Mn/kg/day (3 weeks) to 0.16 μg Mn/kg/day (18 months), with the highest intakes at the youngest age stage we considered, 3 weeks. Estimated daily Mn intake from formula products reconstituted with 0 μg Mn/L water ranged from 130 μg Mn/kg/day (3 weeks) to 4.8 μg Mn/kg/day (18 months) with the highest intakes at 3 weeks. Formula products provided 28–520 times greater than the mean daily intake of Mn from breast milk for the 4 age stages that we considered. Estimated daily Mn intake from formula products reconstituted with water containing 250 μg Mn/L ranged from 12 μg Mn/kg/day to 170 μg Mn/kg/day, which exceeds the United States Environmental Protection Agency Reference Dose of 140 μg Mn/kg/day for adults.ConclusionsMn deficiency is highly unlikely with exclusive breast milk or infant formula feeding, but established tolerable daily intake levels for Mn may be surpassed by some of these products when following labeled instructions.     

Leptin levels in rat offspring are modified by the ratio of linoleic to alpha-linolenic acid in the maternal diet

The supply of polyunsaturated fatty acids (PUFA) is important for optimal fetal and postnatal development. We have previously shown that leptin levels in suckling rats are reduced by maternal PUFA deficiency. In the present study, we evaluated the effect of maternal dietary intake of (n-3) and (n-6) PUFA on the leptin content in rat milk and serum leptin levels in suckling pups. For the last 10 days of gestation and throughout lactation, the rats were fed an isocaloric diet containing 7% linseed oil (n-3 diet), sunflower oil (n-6 diet), or soybean oil (n-6/n-3 diet). Body weight, body length, inguinal fat pad weight, and adipocyte size of the pups receiving the n-3 diet were significantly lower during the whole suckling period compared with n-6/n-3 fed pups. Body and fat pad weights of the n-6 fed pups were in between the other two groups at week one, but not different from the n-6/n-3 group at week 3. Feeding dams the n-3 diet resulted in decreased serum leptin levels in the suckling pups compared with pups in the n-6/n-3 group. The mean serum leptin levels of the n-6 pups were between the other two groups but not different from either group. There were no differences in the milk leptin content between the groups. These results show that the balance between the n-6 and n-3 PUFA in the maternal diet rather than amount of n-6 or n-3 PUFA per se could be important for adipose tissue growth and for maintaining adequate serum leptin levels in the offspring.     

Lactational performance, consummatory behavior, and suppression of estrous cyclicity in rats suckling underfed pups

The role of pups' appetite in the regulation of maternal consummatory behavior (food intake of nursing mothers), lactational performance and postpartum diestrus was studied over a period of 45 days postpartum in rats chronically exposed to either underfed or normally fed pups. Experimental rats (n = 10) daily received 5 pups, 4-10-days-old, that had been deprived of food for the preceding 24 h while under the care of nonlactating foster mothers. Control rats (n = 10) received normally fed pups obtained daily from lactating foster mothers. Throughout the experimental period, the daily milk yield (estimated by litter weight gain), the intake of food and water by the mother, as well as the ratio of litter weight gain to mother's intake of food and water were all markedly higher in rats nursing underfed pups than in rats nursing normally fed pups. After a peak in lactation around Day 15 postpartum, experimental rats produced the same amount of milk during extended lactation as they did in the beginning of lactation, while control rats produced only half the amount of milk during extended lactation as they did in early lactation. Regardless of the nutritional state of the suckling pups, maternal body weight increased progressively over the first four weeks of lactation and remained unchanged during the time of extended lactation. The postpartum diestrus and the subsequent diestrous phase in the time of extended lactation were considerably longer in duration in rats that nursed underfed pups. On Day 45 of lactation, prolactin levels were higher and the adrenal glands were larger in experimental rats than in controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidermal growth factor reduces intestinal apoptosis in an experimental model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating intestinal disease of premature infants. Although end-stage NEC is characterized histopathologically as extensive necrosis, apoptosis may account for the initial loss of epithelium before full development of disease. We have previously shown that epidermal growth factor (EGF) reduces the incidence of NEC in a rat model. Although EGF has been shown to protect intestinal enterocytes from apoptosis, the mechanism of EGF-mediated protection against NEC is not known. The aim of this study was to investigate if EGF treatment elicits changes in expression of apoptotic markers in the ileum during the development of NEC. With the use of a well-established neonatal rat model of NEC, rats were divided into the following three experimental groups: dam fed (DF), milk formula fed (NEC), or fed with formula supplemented with 500 ng/ml EGF (NEC+EGF). Changes in ileal morphology, gene and protein expression, and histological localization of apoptotic regulators were evaluated. Anti-apoptotic Bcl-2 mRNA levels were markedly reduced and pro-apoptotic Bax mRNA levels were markedly elevated in the NEC group compared with DF controls. Supplementation of EGF into formula significantly increased anti-apoptotic Bcl-2 mRNA, whereas pro-apoptotic Bax was significantly decreased. The Bax-to-Bcl-2 ratio for mRNA and protein was markedly decreased in NEC+EGF animals compared with the NEC group. The presence of caspase-3-positive epithelial cells was markedly reduced in EGF-treated rats. These data suggest that alteration of the balance between pro-and anti-apoptotic proteins in the site of injury is a possible mechanism by which EGF maintains intestinal integrity and protects intestinal epithelium against NEC injury.     

Effect of dam factors on milk intake and performance of Belgian Blue suckling calves

Milk intake data were collected at 4-week intervals from Belgian Blue double-muscled (BBDM) suckling calves up to 16 weeks after birth. Dams were fed at 100%, 90%, 80% or 70% of their energy requirements during a 140-day indoor period from the beginning of December to the end of April (restriction period). Afterwards, cows were turned out on pasture (re-alimentation period). Mean calving date was 3 June, but parturitions were spread over the year. A total of 521 individual milk intake (IMI) and 120 average daily milk intake (AMI, mean of IMI) records were collected. IMI amounted to 7.0 ± 2.2 kg/day and was not affected by energy level during the indoor period. It was highest in May and June. Calves born out of multiparous cows consumed more milk than those born out of primiparous cows (7.4 v. 6.2 kg per day; P = 0.001), while intake tended to be higher in female than in male calves (7.2 v. 6.8 kg per day; P = 0.044). Dam age at calving, parity, post partum weight and body condition were only weakly correlated with AMI (r 0.4). AMI was correlated with pre-weaning live-weight gain (r = 0.807) and weaning weight (r = 0.783), with a slightly higher correlation for male than for female calves. Daily live-weight gain during the suckling period was increased by 79 g per extra kg daily milk intake on average, and by 86 and 74 g, respectively, for male and female calves. Calf solid feed intake was low, even when milk intake was low. In terms of net energy intake, milk was only substituted for solid feed by 29%. It can be concluded from the calf intake that milk production in BBDM cows is comparable with that of cows from other beef breeds, but its variation is considerable, complicating an accurate estimation.     

Lack of an effect of dairy protein (casein) and soy protein on plasma cholesterol of strict vegetarians. An experiment and a critical review

In animals, ingestion of casein, the principal protein in milk, causes hypercholesterolemia, whereas in humans this effect has not been documented. We added 27 g of casein (the amount in 1.1 liters of skim milk and nearly twice the average U.S. intake) for 20 days, and 27 g of soy protein for an additional 20 days to the daily diet of 13 strict vegetarians who consumed no other animal protein during the study period. The protein supplementation increased the ad libitum daily protein intake from 59 g to 82 g. Levels of plasma LDL, HDL, and total cholesterol were not significantly affected by either the casein or the soy supplementation. Over the 40 days of protein supplementation, there were progressive decreases in VLDL cholesterol (VLDL-C) and increases in triglycerides (TG) from pre-study levels, demonstrated by an overall change in the VLDL-C/TG ratio from 0.30 to 0.17 (P = 0.003). Caloric intake and body weight did not change significantly. From the literature on dietary protein and blood lipid levels and from the present data, it appears that neither the amount of protein in the diet nor whether the protein comes from animal or vegetable sources has an important effect on plasma LDL and HDL levels in humans when consumed in physiologic amounts.     

Milk intake in blue fox (Alopex lagopus) and silver fox (Vulpes vulpes) cubs in the early suckling period

Milk intake of fox cubs (2-16 days of age; body weight, 96-649 g) in ten blue fox litters and ten silver fox litters were measured by the water isotope dilution (WID) technique following a single intraperitoneal injection of tritiated water (3HHO). Litter size varied from four to 14 in blue foxes and from three to eight in silver foxes. Silver fox cubs had higher birth weights than blue foxes. Inter-species body weights and growth rates were apparently dependent on litter size and the dam's constitution. In both species growth rate increased with age and body weight (7-35 g per day). In the cubs, the biological half-life of body water turnover (BWT) rose from 1.5 days at 2-3 days of age to 2.5 days at 13-16 days of age, although a considerable scatter was seen. The mean daily milk intake of the cubs varied with body weight, from 31 to 193 g per day, whereas daily milk intake per unit of body mass remained stable at 30-35 g per 100 g body weight. The ratio of milk intake to body weight gain varied considerably among cubs, averaging 4.5 g/g during the 3-week experimental period. In suckling fox cubs, the calculated daily intake of metabolically energy (ME) corresponded fairly with the estimated energy requirements for growth and maintenance of the young. Finally, the applicability and the accuracy of the WID technique was evaluated in ten 3-week-old fox cubs, by tube-feeding with a milk replacer for 48 h, which documented that the daily rates of milk intake and water turnover can be accurately measured in suckling fox cubs by the WID technique following a single injection of 3HHO.     

Daily protein and energy intakes of infants fed a commercial infant formula with a reduced protein concentration of 2.2 g/100 kcal: an impact of feeding interval on energy intake

ABSTRACT

We evaluated the protein and energy intakes of infants fed commercial infant Formula A (protein, 2.2 g/100 kcal; energy, 68 kcal/100 mL) and examined whether changes in feeding intervals are involved in constant energy intake. Daily nutritional intake of 378 Formula A-fed infants was assessed using reference values and compared to that of infants fed Formulas B (protein: 2.3 g/100 kcal, energy: 68 kcal/100 mL) and C (protein: 2.4 g/100kcal, energy: 70 kcal/100 mL). From 15 to 149 days of age, the mean formula volume and protein intake were 758–887 mL/day and 11.4–13.3 g/day, respectively, higher than the protein intake of breast-fed infants. Daily energy intake (86–129 kcal/kg/day) was comparable to the estimated energy requirements. Feeding intervals were shorter in infants fed Formulas A and B than in those fed Formula C, whereas energy intake was similar. The protein intake of infants decreased as the protein concentration per energy in infant formula was reduced, and accordingly the protein intake of Formula A-fed infants was significantly lower than that of Formula C-fed infants. In conclusion, the new composition of Formula A is suitable in protein and energy intake of infants, and daily energy intake remains constant by shortening in feeding intervals when the energy concentration in infant formula is reduced.

Clinical Trial Registration: UMIN000023110     

The effect on growth of feeding supplemental milk or baby food to the suckling rat

Suckling rats were fed synthetic rat milk or baby food as dietary supplements amounting to 10% of their total expected daily caloric intake from day 10 to day 16 of life. On day 17, their body lipid levels were significantly higher than those of control pups, and they remained high throughout a 6-week postweaning period of ad libitum food intake. Protein content (at 17 and 60 days of age) was similar in experimental and control groups. Seventeen-day-old pups that had been fed supplemental baby food showed a small but significant increase in DNA levels but no accompanying increase in lean body mass. Rats that received supplemental milk weighed more than either those that received baby food or controls at 17 days of age; however, both experimental groups weighed considerably more at weaning (21 days) than controls. At 60 days of age, their weights were again similar to those of control rats.     

Energy metabolism and protein balance in growing rats fed different levels of dietary fibre and protein

A study was performed to investigate the effect of different levels of dietary fibre (DF) and dietary protein on visceral organ size, digestibility, nitrogen balance and energy metabolism in rats. Thirty-six male Wistar rats, initial body weight about 76 g, were used in a factorial design consisting of three levels of DF (low, 100 g/kg DM; medium, 250 g/kg DM and high, 290 g/kg DM) and two levels of dietary protein (low, 120 g/kg DM and high, 223 g/kg DM). The added fibre source was soybean hulls and Danish fish meal was used as sole source of dietary protein. Measurements of gas-exchange were done on six rats (one group) while urine and faeces were collected individually. The ratio of food/empty body gain increased (P < 0.05) with increasing DF and decreasing levels of dietary protein. The weight of the digestive tract was larger (P < 0.05) in rats fed the high fibre diet than in those fed the low fibre diet. The digestibility of nutrients and energy decreased linearly with increasing level of soybean fibre (P < 0.05). An increased intake of DF was associated with a concomitant loss of protein and energy to faeces. The microbial degradation of NSP and other unabsorbed carbohydrates caused considerably changes in N metabolism of the colon. In rats fed the low protein diets increased levels of DF decreased N excretion in urine and increased N excretion in faeces, while the ratio of retained/digested protein remained constant. When rats were fed the high protein diet protein retention dropped in response to DF both absolute and relative to digested amount, indicating that energy intake could be a limiting factor. Heat production as a percentage of metabolizable energy (HP/ME) was higher (P < 0.05) in rats fed the low protein diet than in rats fed the high protein diet, but no significant difference was found among DF levels.