Growth and development of rats artificially reared on a high or a low plane of nutrition

Smart, James L.; Stephens, Danielle; Katz, Hillary B.

doi:10.1079/bjn19830058

Cited by 34 publications

(52 citation statements)

References 25 publications

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“…Difficulties have been encountered in obtaining normal body and organ growth in rats artificially reared on milk substitutes (Smart et al 1983(Smart et al , 1984), but we think that we have overcome these by using a regimen in which the pups are given expressed rats' milk for the first few days of artificial rearing and then changed gradually on to a milk-substitute which…”

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confidence: 99%

Effects of early-life undernutrition in artificially reared rats: subsequent body and organ growth

et al. 1987

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I. Four groups of rat pups were reared: mother-reared (MR) control (well-fed) and undernourished (MRC and MRU respectively) and artificially reared (AR) control and undernourished (ARC and ARU respectively). Pups for artificial rearing were fitted with a gastric cannula on postnatal day 5 and were fed, by intermittent gastric infusion, expressed rats' milk (days 5-7), mixtures of rats' milk and milk-substitute (days 8-16), and milksubstitute only (days 17-20). Solid food was available to MR pups throughout and to AR pups from day 14. Undernutrition, imposed from postnatal days 5 to 25, was effected initially by underfeeding the mother (MRU) or by infusing restricted quantities of milk (ARU). Weaning was at 21 d and undernutrition from day 21 to day 25 was by restricting the supply of solid food. A11 rats were fed ad lib. from 25 d.2. The developmental milestone, eye-opening, was delayed by undernutrition but unaffected by artificial rearing.3. Growth curves in body-weight during the refeeding phase were influenced most by previous undernutrition and to a lesser extent (also negatively) by artificial rearing. 4.Fourteen measures of body and organ growth were taken at autopsy at 39 weeks. Twelve measures were affected by nutrition and only four by rearing (weight of whole body, epididymal fat pads, renal fat pads and adrenals).5. AR rats had lighter epididymal and renal fat pads than MR rats perhaps due to the low fat content of the expressed milk they received early in artificial rearing.

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Effects of early-life undernutrition in artificially reared rats: subsequent body and organ growth

et al. 1987

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“…For this reason, the orogastric tube may be most efficacious in younger pups and gastrostomy in the older PUPS. The formula described herein is an improvement over those used by earlier investigators, because it more closely resembles rat milk, allows for manipulation of vitamin or major nutrient content, and is less hypertonic than those based on cow's milk (452 versus 670 mosmol/kg, respectively (3,7).…”

Section: Intragastric Feedingsmentioning

confidence: 99%

“…Of the six rats which died after 24 h of tube feeding, four showed necropsy findings consistent with aspiration that appeared to be due to dislodgement of the tubes and subsequent infusion of the formula into the hypopharynx. Two died, after 4 and 5 days of tube feeding, as a result of intestinal complications associated with intestinal distension, termed by Smart et al (7) as "bloat." There was no evidence of intramural air or other finding suggestive of necrotizing enteritis.…”

Section: Intragastric Feedingsmentioning

confidence: 99%

“…(Pediatr Res 20: 1248-1251,1986) Abbreviation EGF, epidermal growth factor Artificial feeding of infant rats provides a useful model for study of the effect of various nutritive and nonnutritive milk constituents during early development (I), as well as psychological effects of social deprivation (2). Most investigators, however, have utilized gastrostomized rats fed a formula based on evaporated or whole cow's milk (1)(2)(3)(4)(5)(6)(7). The invasive nature of the gastrostomy and the inability to decrease or delete a particular nutrient in the formula are serious shortcomings of these proce-dures.…”

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Effect of Epidermal Growth Factor and Artificial Feeding in Suckling Rats

et al. 1986

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ABSTRACT. To evaluate the effects of epidermal growth factor (EGF) in dietary milk, a new method of delivering an artificial (EGF-deficient) formula was developed using 42 rat pups, 1-14 days of age. In a second study the effect of EGF was evaluated in suckling rats from 3-11 days of age: group 1, mother-fed; group 2, mother-fed plus daily injections of EGF (0.1 hg/g body weight); group 3, artificial milk fed with added EGF (62 ng/ml); and group 4, artificial milk fed without EGF. Each group consists of nine rats. In group 2 there was premature eye opening and tooth eruption and a significant reduction in body weight and weight of liver, kidney, thyroid, and thymus but an increase in length of the intestine and weights of stomach, pancreas, lung, and adrenal (p < 0.04), when compared to group 1.Both groups 3 and 4 showed premature tooth eruption and eye opening, and their body weights and most organ weights were similar to group 2; exceptions were a smaller stomach, thyroid, thymus, lung, and adrenal, which were similar to those in group 1. In addition, intestinal length in groups 3 and 4 were similar to the mother-fed EGF-treated pups (group 2). There was no difference in intestinal length between the artificially fed pups, whether or not they received oral EGF. These findings demonstrate a new and effective technique of artificial feeding and suggest that the increase in intestinal length caused by injections of EGF (0.1 pg/g body weight) can also be induced by feeding an artificial milk with or without physiologic levels of EGF. (Pediatr Res 20: 1248-1251,1986) Abbreviation EGF, epidermal growth factor Artificial feeding of infant rats provides a useful model for study of the effect of various nutritive and nonnutritive milk constituents during early development (I), as well as psychological effects of social deprivation (2). Most investigators, however, have utilized gastrostomized rats fed a formula based on evaporated or whole cow's milk (1-7). The invasive nature of the gastrostomy and the inability to decrease or delete a particular nutrient in the formula are serious shortcomings of these proce-

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“…Despite the best attempts to mimic natural mouse milk with the RMS, there may be unknown factors present or absent from the milk substitute that may be responsible for changes in organ development, such as growth factors and hormones (4). In previous studies, investigators demonstrated that rat pups that were reared artificially with various substitutes showed differences in their organ development (8,9,14). Most of these earlier studies, however, used RMS with a lower protein and higher carbohydrate concentration than is used in our current study.…”

Section: Artificial Rearing Of Mouse Pupsmentioning

confidence: 99%

Artificial Rearing of Mouse Pups: Development of a Mouse Pup in a Cup Model

et al. 2004

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Artificial rearing of rat pups has been used in the investigation of the neonatal gut. We propose to adapt the model of artificially rearing rat pups for use in mouse pups, thereby allowing the use of transgenic animals for our research. We hypothesized that gastrostomy catheters may be placed successfully into neonatal mouse pups and that the pups may be artificially reared without significant alterations in their growth or intestinal development. Gastrostomy tubes are placed into 5-d-old mouse pups [artificially reared (AR); n ϭ 32], and the mice are fed rodent milk substitute. Littermate pups [maternally reared (MR); n ϭ 22] are used as controls. After 5 d, pups are killed and their organs are harvested. Intestinal villus measurements, protein content, and DNA content are determined. Data are reported as mean Ϯ SEM, compared with appropriate statistical methods, and significance is determined at P Ͻ 0.05. Initial weights and lengths are not different between the two groups, but after 5 d, MR pups weigh more than their AR counterparts (5.0 Ϯ 0.13 versus 4.1 Ϯ 0.14 g, MR versus AR; P Ͻ 0.01). However, the pups' length and the intestinal villus height-to-width ratios, protein, and DNA content are not different between the MR and AR pups. To our knowledge, this is the first report of artificially rearing mouse pups. Development of this technique will permit nutritional manipulation in neonatal mice, a mammalian model wherein the genome is sequenced and transgenic mutants are available. The nutritional status of the newborn and its effects on disease states and intestinal development have long been an area of intense study. Animal model systems are widely used and have proved to be effective for the investigation of a number of illnesses, with the findings extrapolated to the human condition. The development of a rodent in vivo animal model to study neonatal nutrition has been difficult, primarily because during the time that the animal is suckling from the mother and when the intestine is developing rapidly, it is difficult to control the amount and composition of the diet of the experimental neonate.The technique of implanting an intragastric cannula for artificially rearing rat pups is well established (1). This technique allows for the study of a number of neonatal conditions with consistent access to the gastrointestinal tract, allowing for the control and manipulation of both the quantity and the composition of dietary intake in the preweanling rat pups. This model has been used extensively to study a myriad of conditions, including the determination of the nutritional demands for normal growth and development (2). It has been used in studies of intestinal maturation and enzymatic development (3). It has also been used to evaluate the effects of different insults, growth factors, and nutrients on the newborn gut (4,5). The rat pup in a cup model has even been used to study the effects of nutrition (6) and toxin ingestion (7) on early brain development. Although the utility of the rat pup in a cup model has b...

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Growth and development of rats artificially reared on a high or a low plane of nutrition

Cited by 34 publications

References 25 publications

Effects of early-life undernutrition in artificially reared rats: subsequent body and organ growth

Effects of early-life undernutrition in artificially reared rats: subsequent body and organ growth

Effect of Epidermal Growth Factor and Artificial Feeding in Suckling Rats

Artificial Rearing of Mouse Pups: Development of a Mouse Pup in a Cup Model

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