Artificial rearing of rat pups using rat milk

1990 ◽  
Vol 23 (2) ◽  
pp. 169-178 ◽  
Author(s):  
Elizabeth Moore ◽  
Colleen Stamper ◽  
Jaime Diaz ◽  
Elise Murowchick
Keyword(s):  
2009 ◽  
Vol 66 (3) ◽  
pp. 272-277 ◽  
Author(s):  
Cynthia B de Medeiros ◽  
Alison S Fleming ◽  
Celeste C Johnston ◽  
Claire-Dominique Walker

2003 ◽  
Vol 228 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Malathi Srinivasan ◽  
Suzanne G. Laychock ◽  
David J. Hill ◽  
Mulchand S. Patel

Obese individuals are more likely to suffer from diseases termed the “metabolic syndrome,” which includes type 2 diabetes. It is now recognized that early life dietary experiences play an important role in the etiology of such diseases. In this context, the consequences of a high carbohydrate (HC) dietary intervention in neonatal rats is being studied in our laboratory. Artificial rearing of 4-day-old rat pups on a HC milk formula up to Day 24 results in the immediate onset of hyperinsulinemia, which persists throughout the period of dietary intervention. Several adaptations at the biochemical, cellular, and molecular levels in the islets of these HC rats support the onset and persistence of the hyperinsulinemic condition during this period. Some of these adaptations include a distinct leftward shift in the insulin secretory capacity, increased hexokinase activity, increased gene expression of preproinsulin and related transcription factors and specific kinases in 12-day-old HC islets, and alterations in the number and size of islets. These adaptations are programmed and expressed in adulthood thereby sustain the hyperinsulinemic condition in the postweaning period and form the basis for adult-onset obesity. HC females spontaneously transmit the HC phenotype (chronic hyperinsulinemia and adult-onset obesity) to their progeny. Collectively, our results indicate that even a mere switch in the nature of the source of calories (from fat rich in rat milk to carbohydrate rich in the HC milk formula) during critical phases of early development in the rat results in metabolic programming of islet functions leading to chronic hyperinsulinemia (throughout life) and adult-onset obesity. This metabolic programming, once established, forms a vicious cycle because HC female rats spontaneously transmit the HC phenotype to their progeny. The results from our laboratory in the context of metabolic programming due to neonatal nutritional experiences are discussed in this review.


1983 ◽  
Vol 49 (3) ◽  
pp. 497-506 ◽  
Author(s):  
J. L. Smart ◽  
D. N. Stephens ◽  
H. B. Katz

1. In order to exclude the possibility of differences in maternal care which are known to result from typical methods of undernutrition during the suckling period, rat pups were reared artificially on different planes of nutrition away from their mothers.2. Artificial rearing was accomplished by fitting infant rats with a gastric cannula through which a milk substitute was infused intermittently. Rats were fed thus from 4 to 21 d on a high (ARHI) or a low (ARLO; 44% of ARHI level) plane of nutrition. Underfeeding of the ARLO group was continued till 25 d, after which all rats were given a good-quality pelleted diet ad lib.3. Compared with mother-reared (MR) litter-mates, ARHI rats showed advanced eye-opening and, at 21 and 25 d, they resisted restraint more strongly.4. Growth in body-weight of ARHI and MR rats was similar but, when autopsied at 32 weeks, the ARHI rats were shorter (nose–rump length) and had lighter gastrocnemius muscles, adrenals and brains, but heavier epididymal-fat pads.5. ARLO rats had deficits at 32 weeks compared with ARHI rats in whole body, kidney and epididymal-fat-pad weights, and in tibia length.6. In a second experiment, ARHI and MR rats were killed at 21 d. All the differences found at 32 weeks were already present at 21 d. In addition, the ARHI pups had enlarged livers and intestines but shorter tibias.7. The milk substitute, which is one commonly used in such studies, has a low protein and high carbohydrate content compared with rats' milk. This difference probably caused the abnormal organ growth of ARHI rats.


1994 ◽  
Vol 14 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Mulchand S. Patel ◽  
Satyaprasad Vadlamudi ◽  
Gary L. Johanning

1982 ◽  
Vol 112 (5) ◽  
pp. 841-847 ◽  
Author(s):  
Jaime Diaz ◽  
Elizabeth Moore ◽  
Frances Petracca ◽  
Jack Schacher ◽  
Colleen Stamper
Keyword(s):  

1982 ◽  
Vol 15 (4) ◽  
pp. 297-307 ◽  
Author(s):  
James R. Goldenring ◽  
Bennett A. Shaywitz ◽  
Robert S. Wool ◽  
David K. Batter ◽  
George M. Anderson ◽  
...  

2003 ◽  
Vol 90 (1) ◽  
pp. 120-127 ◽  
Author(s):  
Stacy A. Kinirons ◽  
Mary S. Shall ◽  
J. Ross McClung ◽  
Stephen J. Goldberg

This study's purpose was to examine the influence of an altered activity level, via artificial rearing, on the contractile properties, myosin heavy chain phenotypes (MHC), and muscle fiber sizes of the developing rat tongue retractor musculature. Artificially reared rat pups were fed through a gastric cannula, eliminating nutritive suckling from postnatal day 4 to postnatal day 14. Rat pups were observed immediately following artificial rearing (postnatal day 14) and after a 1-mo resumption of function (postnatal day 42). The contractile characteristics of the tongue retractor musculature were measured in response to stimulation of the hypoglossal nerve. At postnatal day 14, artificially reared rat pups demonstrated significantly longer twitch half-decay times, lower fusion frequencies, and a marked decrease in fatigue resistance. These contractile speed and fatigue characteristics were fully recovered following a 1-mo resumption of function. MHC phenotypes of the styloglossus muscle (a tongue retractor) were determined by gel electrophoresis. At postnatal day 14, artificial rearing had not altered the MHC phenotype or muscle fiber sizes of the styloglossus muscle. However, following a 1-mo resumption of function artificially reared rat pups demonstrated a small but significant increase in MHCIIa expression and decrease in MHCIIb expression compared with dam-reared rats. These results support artificial rearing as a useful model for altering the activity level of the tongue and suggest that normal suckling behavior is necessary for the normal postnatal development of the tongue retractor musculature. This may also be the case for premature infants necessarily fed artificially.


1987 ◽  
Vol 57 (1) ◽  
pp. 3-11 ◽  
Author(s):  
J. Tonkiss ◽  
J. L. Smart ◽  
R. F. Massey

1. Rat pups were artificially reared (AR) from post-natal day 5 by intermittent gastric infusion. Mother-reared (MR) siblings served as controls. Fourteen measures of body and organ growth were taken at the end of each experiment.2. In Expt 1, two batches of pups were given rats' milk only, obtained by manual expression from anaesthetized dams.3. The first batch, reared to 12 d, grew less well than the MR group, probably because they received too little milk. However, relative to body-weight, organ weights were as great or greater than those of MR pups, except for heart weight. The second batch, given more milk and reared to 20 d, showed no deficits in organ or body-weights, but excesses in kidney, gastrocnemius muscle, stomach and caecum weights. There were no losses from ‘bloat’, a condition of gastrointestinal distention often encountered in artificial rearing with milk substitutes.4. Obtaining rats' milk is extremely labour-intensive and in Expt 2, more economical regimens were devised in which pups were started off on expressed rats' milk and then changed to a milk substitute resembling rats' milk in composition, either abruptly at 12 d or gradually between 8 and 17 d.5. Both regimens were successful, in that there were no losses from bloat and most measures of growth were at least as great as in the MR group. Only heart weight was lower in both AR groups and adrenal weight in the abruptly changed AR group. The weights of the stomach and caecum and the length of the small intestine were all high in both AR groups.6. It is concluded that giving rat pups expressed rats' milk for the first few days of artificial rearing largely avoids the problem of bloat and results in satisfactory growth.


1987 ◽  
Vol 58 (2) ◽  
pp. 245-255 ◽  
Author(s):  
J. L. Smart ◽  
R. F. Massey ◽  
S. C. Nash ◽  
J. Tonkiss

1. 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 milk-substitute 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. All rats were fedad 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.


1999 ◽  
Vol 277 (6) ◽  
pp. E1061-E1069 ◽  
Author(s):  
Ravikumar Aalinkeel ◽  
Malathi Srinivasan ◽  
Satish C. Kalhan ◽  
Suzanne G. Laychock ◽  
Mulchand S. Patel

Artificial rearing of 4-day-old rat pups on a high-carbohydrate (HC) milk formula results in the immediate onset of hyperinsulinemia. To evaluate these early changes, studies on pancreatic function were carried out on 12-day-old HC rats and compared with age-matched mother-fed (MF) pups. The plasma insulin and glucagon contents were increased sixfold and twofold, respectively, in HC rats compared with MF rats. There was a distinct leftward shift in the glucose-stimulated insulin secretory pattern for HC islets. HC islets secreted insulin in the absence of any added glucose and in the presence of Ca2+ channel inhibitors. The activities of glucokinase, hexokinase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate dehydrogenase complex were significantly increased in HC islets compared with MF islets. The protein contents of GLUT-2 and hexokinase were significantly increased in HC islets. These findings indicate that a nutritional intervention in the form of a HC formula only during the suckling period has a profound influence on pancreatic function, causing the onset of hyperinsulinemia.


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