scholarly journals Growth and development of rats artificially reared on rats 'milk or rats' milk/milk-substitute combinations

1987 ◽  
Vol 57 (1) ◽  
pp. 3-11 ◽  
Author(s):  
J. Tonkiss ◽  
J. L. Smart ◽  
R. F. Massey
Keyword(s):  
Growth And Development ◽  
Gastrocnemius Muscle ◽  
Heart Weight ◽  
Artificial Rearing ◽  
Organ Growth ◽  
Organ Weights ◽  
Rat Pups ◽  
Body Weights ◽  
Milk Substitute ◽  
Milk Substitutes

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.

scholarly journals Growth and development of rats artificially reared on different milk-substitutes

1984 ◽  
Vol 52 (2) ◽  
pp. 227-237 ◽  
Author(s):  
J. L. Smart ◽  
D. N. Stephens ◽  
J. Tonkiss ◽  
N. S. Auestad ◽  
J. Edmond
Keyword(s):  
Body Weight ◽  
High Energy ◽  
Control Group ◽  
Interscapular Brown Adipose Tissue ◽  
Organ Growth ◽  
Rat Pups ◽  
Brown Adipose ◽  
Milk Substitute ◽  
Milk Substitutes ◽  
Catch Up

1. Rat pups were artificially reared (AR) from postnatal day 4 or 5 till day 20 or 21, by fitting them with gastric cannulas through which milk-substitutes could be infused automatically.2. Three milk-substitutes were compared: milk M, the usual diet for AR studies, which was somewhat low in protein and very high in carbohydrate; milk A, which resembled rats' milk much more closely in composition; and milk isoM, which was based on the high-energy milk M but was made isoenergetic with milk A. Pups given these diets were termet ARM, ARA and ARisoM respectively. Siblings of the AR rats were left with their mothers to form a mother-reared (MR) control group. Rats were autopsied at 20 or 21 d.3. Growth in body-weight of all groups of AR pups lagged behind that of their MR siblings for about the first week of AR, but the ARM group showed complete catch-up and the ARA group partial catch-up in body-weight during the second week. ARisoM rats were growth-retarded throughout.4. Inspection of organ weights expressed relative to body-weight revealed disturbances of organ growth in all AR groups compared with MR animals. ARM rats showed excessive epididymal fat pad and liver weights, but deficits in gastrocnemius muscle, heart and adrenal weights. In contrast, ARA rats usually displayed increased spleen and stomach weights, but lower weight of interscapular brown adipose tissue. ARisoM rats had high brain, liver and stomach weights and low muscle and spleen weights relative to body-weight. All AR groups had elongated small intestines.5. Hence the patterns of abnormal organ growth differed between groups. Those shown by the ARM and ARisoM groups seemed the more seriously abnormal. The diet approximating the composition of rats' milk (milk A) appears, as intended, to be an improved milk-substitute.

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

1987 ◽  
Vol 58 (2) ◽  
pp. 245-255 ◽  
Author(s):  
J. L. Smart ◽  
R. F. Massey ◽  
S. C. Nash ◽  
J. Tonkiss
Keyword(s):  
Early Life ◽  
Growth Curves ◽  
Solid Food ◽  
Whole Body ◽  
Artificial Rearing ◽  
Organ Growth ◽  
Rat Pups ◽  
Milk Substitute ◽  
Eye Opening ◽  
Fat Pads

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.

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

1983 ◽  
Vol 49 (3) ◽  
pp. 497-506 ◽  
Author(s):  
J. L. Smart ◽  
D. N. Stephens ◽  
H. B. Katz
Keyword(s):  
Whole Body ◽  
Artificial Rearing ◽  
Rat Pups ◽  
Low Protein ◽  
Epididymal Fat ◽  
Milk Substitute ◽  
Eye Opening ◽  
Pelleted Diet ◽  
Gastrocnemius Muscles ◽  
Tibia Length

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.

The artificial rearing of calves and their growth on grass diets: I. The effect of type and temperature of milk substitute given ad libitum

1969 ◽  
Vol 73 (2) ◽  
pp. 279-287 ◽  
Author(s):  
J. C. Tayler ◽  
C. R. Lonsdale
Keyword(s):  
Drinking Water ◽  
Weight Gain ◽  
Milk Powder ◽  
Live Weight ◽  
Sole Source ◽  
Artificial Rearing ◽  
Live Weight Gain ◽  
Milk Substitute ◽  
Milk Substitutes ◽  
Ad Libitum

SUMMARYTwo experiments were carried out to study the effect of the ad libitum feeding of whole-milk substitutes, either warm or cold, and the availability of drinking water, on the level of food intake and live-weight gain of calves. Freshly cut grass or pasture was the sole source of solid feed.In Exp. 1 forty Hereford x Friesian male calves were reared individually indoors in a 2x2x2 factorial design experiment. The treatments were full-cream milk powder υ milk substitute, temperature at which the milk was offered, and drinking water υ no drinking water available to the calves. Fresh grass was cut daily and fed ad libitum to all animals from the sixth day of treatment.In Exp. 2, twelve Hereford x Friesian male calves were reared at pasture on warm or cold full-cream milk during weeks 1–7, and on milk substitute during weeks 8–15.During both experiments calves receiving warm milk drank slightly more than calves receiving cold milk; this difference was significant in Exp. 1 only. There was a tendency for calves receiving cold milk to make higher live-weight gains (0·05 < P < 0·1) when drinking water was available than when it was not. In Exp. 1, the rates of live-weight gain of calves receiving warm or cold milk substitute with drinking water available were 0·99 and 0·89 kg/head/day, respectively: for calves receiving full-cream milk powder the corresponding rates were 0·86 and 0·80 kg/head/day. When drinking water was not available the rates of gain of calves on warm or cold milk substitute were respectively 0·93 and 0·82 kg/head/day, and on full-cream milk powder, 0·94 and 0·55 kg/head/day.In Exp. 2 the rate of live-weight gain measured during the first 7 weeks, whilst calves were receiving full-cream milk powder, was 0·88 kg/head/day irrespective of the temperature at which the milk was given. During weeks 8–14 milk substitute was given, which resulted in rates of live-weight gain of 1·05 kg/head/day for calves receiving warm milk and 0–92 kg/head/day for calves receiving cold.The rates of gain attained on cold milk are considered adequate for rearing calves intended for an intensive system of production. It is also suggested that the use of cold milk could facilitate a marked decrease in the daily labour requirements associated with the artificial rearing of calves.

Effects of progesterone induced postmaturity on CBG and pituitary-adrenal activities in the rat foetus

1986 ◽  
Vol 112 (3) ◽  
pp. 396-403 ◽  
Author(s):  
Jean Paul Dupouy ◽  
Alain Chatelain
Keyword(s):  
Binding Capacity ◽  
Sharp Decrease ◽  
Plasma Corticosterone ◽  
Corticosterone Concentration ◽  
Rat Pups ◽  
Body Weights ◽  
Normal Rat ◽  
Severe Jaundice ◽  
High Level ◽  
Subsequent Rise

Abstract. CBG and pituitary-adrenal activities were investigated in intact rat foetuses, in newborns spontaneously delivered by vaginal way and in postmature foetuses from mothers with delayed parturition caused by daily progesterone injection from day 20 of gestation. The postmature foetuses had lower body weights and higher adrenal weights on day 22, 23 and 24 of gestation than newborns of the same conceptional age. The corticosterone binding capacity of the plasma as well as the binding capacity of CBG for corticosterone decreased in intact foetuses for the last 3 days of gestation and stayed very low in pups from day 0 to day 8 postpartum. These parameters decreased more slowly in postmature foetuses; however, the differences between the latter and intact foetuses or newborns were not statistically significant. Similar evolution occurred in intact pregnant and suckling females as well as in females with prolonged gestation. The fall in CBG activity in normal rat pups and the subsequent rise in free steroids could explain a sharp decrease in plasma ACTH levels as well as the drop in adrenal and plasma corticosterone concentration. In foetuses with prolonged gestation, the same phenomenon did not occur. Stress conditions produced by maintaining growing foetuses in utero and the development of severe jaundice maintained high ACTH levels. In contrast, the fall in adrenal and plasma corticosterone concentrations in spite of the high level of circulating ACTH could be mainly due to the progesterone inhibition of the steroidogenic activity of the foetal adrenals.

Oral (Drinking Water) Two-Generation Reproductive Toxicity Study of Bromodichloromethane (BDCM) in Rats

2002 ◽  
Vol 21 (2) ◽  
pp. 115-146 ◽  
Author(s):  
M. S. Christian ◽  
R. G. York ◽  
A. M. Hoberman ◽  
L. C. Fisher ◽  
W. Ray Brown
Keyword(s):  
Drinking Water ◽  
Reproductive Toxicity ◽  
Clinical Signs ◽  
Sperm Parameters ◽  
Feed Consumption ◽  
Exposure Level ◽  
Organ Weights ◽  
Reduced Body ◽  
Body Weights ◽  
Adult Exposure

Bromodichloromethane (BDCM) was tested for reproductive toxicity in a two-generation study in CRL SD rats. Thirty rats/sex/group/generation were continuously provided BDCM in drinking water at 0 (control carrier, reverse osmosis membrane-processed water), 50, 150, and 450 ppm (0,4.1 to 12.6, 11.6 to 40.2, and 29.5 to 109.0 mg/kg/day, respectively). Adult human intake approximates 0.8 μg/kg/day (0.0008 mg/kg/day). P and F1 rats were observed for general toxicity (viability, clinical signs, water and feed consumption, body weights, organ weights [also three weanling F1 and F2 pups/sex/litter], histopathology [10/sex, 0-and 450-ppm exposure groups]) and reproduction (mating, fertility, abortions, premature deliveries, durations of gestation, litter sizes, sex ratios, viabilities, maternal behaviors, reproductive organ weights [also three weanling F1 and F2 pups/sex/litter], sperm parameters, and implantations. F1 rats were evaluated for age at vaginal patency or preputial separation. Ten P and F1 rats/sex from the 0-and 450-ppm exposure groups and rats at 50 and 150 ppm with reduced fertility were evaluated for histopathology (gross lesions, testes, intact epididymis, all F1 dams for number of primordial follicles). Developmental parameters in offspring included implantation and pup numbers, sexes, viabilities, body weights, gross external alterations, and reproductive parameters (F1 adults). Toxicologically important, statistically significant effects at 150 and/or 450 ppm included mortality and clinical signs associated with reduced absolute and relative water consumption, reduced body weights and weight gains, and reduced absolute and relative feed consumption (P and F1 rats). Significantly reduced body weights at 150 and 450 ppm were associated with reduced organ weights and increased organ weight ratios (% body and/or brain weight). Histopathology did not identify abnormalities. Small delays in sexual maturation (preputial separation, vaginal patency) and more F1 rats with prolonged diestrus were also attributable to severely reduced pup body weights. Mating, fertility, sperm parameters, and primordial ovarian follicular counts were unaffected. The no-observable-adverse-effect level (NOAEL) and the reproductive and developmental NOAELs for BDCM were at least 50 ppm (4.1 to 12.6 mg/kg/day), 5125 to 15,750 times the human adult exposure level, if delayed sexual maturational associated with severely reduced body weights is considered reproductive toxicity. If considered general toxicity, reproductive and developmental NOAELs for BDCM are greater than 450 ppm (29.5 to 109.0 mg/kg/day), or 36,875 to 136,250 times the human adult exposure level. Regardless, these data indicate that BDCM should not be identified as a risk to human reproductive performance or development of human conceptuses.

Growth and development of the barren-ground caribou. II. Postnatal growth rates

1968 ◽  
Vol 46 (5) ◽  
pp. 1023-1029 ◽  
Author(s):  
E. H. McEwan
Keyword(s):  
Growth And Development ◽  
Growth Characteristic ◽  
Growth Curves ◽  
Postnatal Growth ◽  
Maintenance Costs ◽  
Cyclical Pattern ◽  
Body Weights ◽  
In Captivity ◽  
Growth Constants ◽  
Slow Growing

The growth curves of minimum body weights of fast-growing caribou reared in captivity and slow-growing wild caribou are compared. Captive animals exhibit a cyclical pattern of growth characteristic of other cervid species. The differences in the declining growth constants of wild caribou compared to captive caribou are attributed to environmental factors and activity, resulting in higher maintenance costs.

scholarly journals The Resource-saving technology of growing repair young stock

2020 ◽  
pp. 103-110
Author(s):  
M. Lutsenko ◽  
I. Kudlay
Keyword(s):  
Growth And Development ◽  
Physiological State ◽  
Stable State ◽  
Labor Costs ◽  
Resource Saving ◽  
Ammonia Content ◽  
Recreation Area ◽  
Milk Substitutes ◽  
And Behavior ◽  
Positive Effect

The article highlights the results of research dealing with the assessment of the new resource-saving technology for growing heifers that has been developed and implemented in DLC "Terezino" of Bila Tserkva district in Kyiv region. The conditions of keeping and behavior of heifers in individual houses during the first month after birth at subzero temperatures and when transferring them to group cages were studied. Studies have been conducted to assess the effectiveness of milk substitution use. It was found that the composition of milk substitutes have been optimally regulated and such indicators as fat, protein and lactose content are in a stable state. Milk substitutes have a very low bacterial contamination, which has a positive effect on the physiological state of dairy heifers, their growth and development. Animals are sick rarely and provide 100% preservation of young animals. An assessment of new easily build premises in ensuring a quality microclimate has been provided. It has been established that the presence of side curtains and lightaeration ridge in the construction of these premises increases air exchange and reduces the level of harmful gases to a minimum level. The ammonia content in the placement constitutes 1.75 mg / m3 against 22 mg / m3 in traditional premises. The presence of hydrogen sulfide is twice less indoors and constitutes (5.2 mg / m3 vs. 10 mg / m3 according to regulations). It has been established that the division of sections for keeping of repair heifers of the cattle for feeding and recreation area has a positive effect on their behavior, and the presence of a feed table and feeding of heifers with complete ration wet mixes ensures their growth and development in accordance with existing regulations. The use of new resource-saving technology for growing of breeding replacement heifers in this farm allows to reduce labor costs for the production of 1centner of growth up to 3.7 people / hour against 9.2 people/ hour according to traditional technologies. Key words: resource-saving technology, repair heifers, individual houses, milk substitutes, easily assembled premises.

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):  
Artificial Rearing ◽  
Rat Pups

Commentary on Breast-Feeding and Infant Formulas, Including Proposed Standards for Formulas

PEDIATRICS ◽  
1976 ◽  
Vol 57 (2) ◽  
pp. 278-285
Author(s):  
Lewis A. Barness ◽  
Alvin M. Mauer ◽  
Malcolm A. Holliday ◽  
Arnold S. Anderson ◽  
Peter R. Dallman ◽  
...  
Keyword(s):  
Human Milk ◽  
Breast Feeding ◽  
Growth And Development ◽  
Good Growth ◽  
Infant Formulas ◽  
Special Group ◽  
Term Infants ◽  
Excess Lead ◽  
Milk Substitute ◽  
Mineral Levels

This statement proposes recommendations toward increasing the practice of breast feeding. Specific recommendations made for standards of infant formulas as to calorie, protein, fat, vitamin, and mineral levels apply to both milk-based and milk-substitute infant formulas. Such formulas, when used in place of breast-feeding, must supply most or all of the nutrients infants require during the first weeks or months of life. The minimum levels of nutrients per 100 kcal recommended for formulas provide good growth and development in healthy, full-term infants; distinct hazards may be encountered at levels below these. However, no significant advantage is to be gained by providing levels in excess of these minima in normal infants. Recommendations for maximum levels are made only where quantities in excess lead to toxicity; generally, levels near the minima recommended are most desirable because they are the most likely to reflect the composition of human milk, and the least likely to result in any undesirable nutrient to nutrient interaction. The recommendations also can be used as reference standards for formulas for special dietary uses of "medical" formulas. The Committee recommends that "medical" formulas be classified by FDA into a special group under the paragraph dealing with infant formulas.

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