BODY WEIGHT AND FOOD CONSUMPTION OF LACTATING RATS: EFFECTS OF OVARIECTOMY AND OF ARREST AND RESUMPTION OF SUCKLING

1967 ◽  
Vol 38 (3) ◽  
pp. 251-261 ◽  
Author(s):  
K. ÔTA ◽  
A. YOKOYAMA
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Food Consumption ◽  
Ovarian Function ◽  
Progressive Increase ◽  
Ovariectomized Rats ◽  
Milk Secretion ◽  
Lactating Mothers ◽  
Rate Of Increase ◽  
Pregnancy And Lactation

SUMMARY In order to assess the role of the suckling stimulus in the regulatory mechanism of body weight and food consumption of lactating rats, changes in body weight and food intake under various conditions were investigated. The results of the changes in food intake during the oestrous cycle, pregnancy and lactation, and after weaning were consistent with those reported by previous workers. The rate of increase in body weight was similar during dioestrus, early pregnancy, early lactation and after ovariectomy. Food consumption of mother rats was maintained at the lactating level for 24 hr. after the removal of suckling pups on the 12th day of lactation, then it rapidly decreased. Resumption of suckling by foster litters, 5 days after removal of the original litters, caused increase in body weight and food intake as well as the restoration of lactation in both normal and ovariectomized animals. The rate of increase in body weight arising from the resumption of suckling was similar to that observed in the ovariectomized rats that were not resuckled after removal of the litters. The increase in body weight in the resuckled rats was not necessarily associated with the enhanced food intake. In spite of vigorous suckling by pups, food intake of the resuckled animals did not show a progressive increase as in normal lactating mothers until the function of mammary glands was restored and sufficient milk was produced to increase the weight of the foster litters. After restoration of lactation food consumption of the resuckled mothers increased progressively, the increase being closely related to increased milk secretion. The greater food intake in the resuckled rats than in the non-resuckled animals, even before restoration of milk secretion, seems to indicate a direct stimulating effect of the suckling stimulus on appetite; consumption of energy associated with milk secretion is also considered to be one of the main factors in inducing the enhanced food intake in lactating rats. A further possibility that the suckling stimulus participates in the regulation of body weight and food consumption in lactating animals by changing the ovarian function is discussed.

BODY WEIGHT AND FOOD CONSUMPTION OF LACTATING RATS NURSING VARIOUS SIZES OF LITTERS

1967 ◽  
Vol 38 (3) ◽  
pp. 263-268 ◽  
Author(s):  
K. ÔTA ◽  
A. YOKOYAMA
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Food Consumption ◽  
Ovarian Function ◽  
Experimental Period ◽  
Close Correlation ◽  
Female Rats ◽  
Linear Relationships ◽  
Rate Of Increase ◽  
Daily Gain

SUMMARY Changes in body weight and food consumption during lactation in rats nursing various sizes of litters were studied. The rate of increase in body weight of the mother rats during the experimental period (day 3–14 of lactation) was very similar in mothers with different numbers (2, 4, 8 and 12) of suckling pups/litter. It is suggested that the weight increase of adult female rats during lactation is related more closely to the alteration of ovarian function caused by the suckling stimulus than to the enhanced food intake during this period. Both the food intake of mother rats and the daily gain in weight of litters increased as the number of suckling pups/litter increased and as lactation advanced. Linear relationships were observed between the logarithm of the litter size and both the food intake of the mother rats and the weight gain of the litters. The presence of a close correlation between the food intake of mother rats and the quantity of milk produced by them is suggested.

The control of appetite in lactating cows

1972 ◽  
Vol 14 (3) ◽  
pp. 263-281 ◽  
Author(s):  
L. S. Monteiro
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Milk Yield ◽  
Closed Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Lactating Cows ◽  
Body Reserves ◽  
Lactation Curve ◽  
Rate Of Increase

SUMMARYA closed-loop system is proposed for the control of voluntary food intake in lactating cows, and an expression is deduced relating the response of food intake to changes in milk yield and body-weight gain.A closed-loop system necessarily involves a delay in the response to changes in production. The rate of increase of food intake is there- fore slower than the rate of increase in milk yield. The consequent deficit in energy during the rising part of the lactation curve is met by the mobilization of body reserves, which are partly accounted for by losses in body weight. During the declining part of the lactation the delay effect leads to an excess of energy intake and to the replacement of body reserves and, consequently, of body weight.The expression deduced from the model was fitted to four different types of lactation curve corresponding to long and short lactations of Friesians and Jerseys fed ad libitum on a complete diet. The expected food intake based on the control model was contrasted with a linear regression model. The former gave a better account of the variation in food intake in all four types of lactation.The total change in body weight during lactation was partitioned between changes in weight due to the mobilization and replacement of reserves and gain directly attributable to food intake. There was, in general, good agreement between the observed losses in weight occurring at the beginning of lactation and those predicted from the mobilization of reserves for milk production.The physiological implications of the model and the values estimated for the parameters are discussed.

Estrogens and antiestrogens: actions and interactions with fluphenazine on food intake and body weight in rats

1993 ◽  
Vol 264 (6) ◽  
pp. R1214-R1218 ◽  
Author(s):  
J. M. Gray ◽  
S. Schrock ◽  
M. Bishop
Keyword(s):  
Body Weight ◽  
Adipose Tissue ◽  
Weight Gain ◽  
Food Intake ◽  
Ethinyl Estradiol ◽  
Body Weight Gain ◽  
Fatty Acid Synthetase ◽  
Ovariectomized Rats ◽  
Synthetase Activity ◽  
Concurrent Administration

Treatment of ovariectomized rats for 3 days with 2 micrograms estradiol benzoate (E2B), 6 micrograms ethinyl estradiol, or 1-2 mg of either of the antiestrogens nafoxidine or tamoxifen led to similar decreases in food intake, body weight gain, adipose tissue lipoprotein lipase activity, and hepatic fatty acid synthetase activity, despite their different effects on uterine growth and induction of progestin receptors in pituitary and adipose tissue. Longer-term (2 wk) treatment with tamoxifen resulted in similar transient changes in food intake and body weight gain, as did treatment with E2B. Daily administration of 50 micrograms fluphenazine (FLU) led to significant decreases in body weight, although there was no change in food intake. Concurrent administration of FLU with either E2B or tamoxifen led to additive effects on body weight and food intake change. None of the treatments had any effect on in vitro binding of [3H]tamoxifen to antiestrogen binding sites in pooled hypothalamic-preoptic area samples.

scholarly journals An evaluation of the relation between food consumption rate and equilibrium body-weight in male rats

1988 ◽  
Vol 60 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Tom W. Gettys ◽  
Susan Mills ◽  
Donald M. Henrickst
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Food Consumption ◽  
Consumption Rate ◽  
Growth Efficiency ◽  
Intake Rate ◽  
Total Intake ◽  
Food Consumption Rate ◽  
Maintenance Requirements ◽  
Food Intake Rate

1. Two experimental approaches were employed to assess the relation between food consumption rate and maintenance requirements in male weanling rats. The first approach involved restricting food intake in rats previously given free access to food from weaning to 59 d of age. The second approach involved restriction of food intake to various levels after weaning. Maintenance requirements (g foodid per g body-weight (W)) were estimated by dividing the rate of food consumption by the resulting equilibrium W (EBW) for each animal. In addition, food consumption was partitioned into growth-independent (maintenance) and growth-dependent (gain) components by alternately setting W and specific growth rate (W') to zero in an equation relating food intake rate to W and W. Coupling coefficients representing maintenance consumption (g food/d per g W) and gain consumption (g food/g gain) were estimated for each animal by least squares.2. Both techniques for estimating maintenance consumption provided similar estimates within and across experiments, and regardless of when food restriction was imposed or its severity, consumption for maintenance was about 5% W/d.3. The EBW to which animals in each treatment group aspired was directly proportional to that group's food intake rate.4. Coventional measures of growth efficiency were also related to food intake; efficiency decreased with decreasing food intake. Partitioning food consumption into maintenance and gain components revealed that as the rate of food intake decreased, the proportion of total intake consumed for maintenance increased. The results suggest that growth efficiency declines during food intake restriction because proportionately more of total intake is used for maintenance, leaving less available for gain.

Differences in food resource allocation in a long-term selection experiment for litter size in mice 2. Developmental trends in body weight against food intake

2000 ◽  
Vol 71 (1) ◽  
pp. 39-47 ◽  
Author(s):  
W. M. Rauw ◽  
P. Luiting ◽  
M. W. A. Verstegen ◽  
O. Vangen ◽  
P. W. Knap
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Litter Size ◽  
Genetic Factors ◽  
Food Resource ◽  
Growth Efficiency ◽  
Control Line ◽  
Growing Period ◽  
Pregnancy And Lactation ◽  
Maintenance Requirements

AbstractIn the accompanying paper, specific genetic factors for body weight and food intake were identified in non-reproductive male and female mice of a line selected for high litter size at birth (average of 22 born per litter) and a non-selected control line (average of 10 born per litter). The existence of these factors are indicated by variation in efficiency parameters such as growth efficiency and maintenance requirements. Residual food intake (RFI) and Parks’ estimates of growth efficiency (AB) and maintenance requirements (MEm) were used to quantify these factors. In the growing period, females had a higher RFI (are less efficient) than males. At maturity, selected mice had higher RFI than control mice and selected females had higher RFI than selected males. AB was higher in selected-line mice than in control-line mice, and higher in males than in females. MEm was higher in selected-line mice than in control-line mice, and higher in females than in males. The results indicate the existence of specific genetic factors for both growth efficiency and maintenance requirements. Selected females may increase RFI in the adult state to anticipate the metabolically stressful periods of pregnancy and lactation, to support a genetically highly increased litter size.

Endogenous faecal loss of calcium by ruminants

1982 ◽  
Vol 99 (2) ◽  
pp. 355-358 ◽  
Author(s):  
G. D. Braithwaite
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Linear Relationship ◽  
Calcium Metabolism ◽  
Weight Basis ◽  
Weight Increase ◽  
Significant Linear Relationship ◽  
Variable Factor ◽  
Pregnancy And Lactation ◽  
Body Weight Increase

SUMMARYA re-examination of the results from 374 sheep used in previovis studies of calcium metabolism show there is a highly significant linear relationship between endogenous faecal loss of Oa and food intake, endogenous loss increasing by about 0·64 mg/day/kg body weight for each 1 g/day/kg body weight increase in food intake. This loss was unaltered by Ca intake or by pregnancy and lactation but was slightly higher in young animals than in adult animals given the same Ca intake on a body-weight basis. It is suggested that a variable factor for endogenous Ca loss, based upon some measure of level of feeding, should be introduced into rationing schemes.

Influence of pregnancy and lactation on Na appetite of BALB/c mice

1988 ◽  
Vol 255 (6) ◽  
pp. R1020-R1024
Author(s):  
M. McBurnie ◽  
D. Denton ◽  
E. Tarjan
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Sodium Intake ◽  
Control Group ◽  
Base Line ◽  
Sodium Appetite ◽  
Great Excess ◽  
Pregnancy And Lactation ◽  
Voluntary Intake

The effect of pregnancy and lactation on sodium appetite, water, and food intake of young adult BALB/c mice was studied. Voluntary sodium intake increased fourfold during the last 3 days of gestation. Water and food intake and body weight also increased significantly. During the last 14 days of lactation, sodium intake was increased significantly three- to fivefold, relative to base-line period and a control group. Large significant increase of water and food intake occurred also during lactation. After weaning, intake returned to base line. Calculation of sodium sequestered in young in utero and provided to pups during lactation showed increased voluntary intake in great excess of metabolic need, suggestive of hormonal determination of sodium appetite during reproduction as in wild rabbits.

THE INFLUENCE OF SUCKLING ON FOOD INTAKE AND GROWTH OF ADULT FEMALE RATS

1954 ◽  
Vol 10 (4) ◽  
pp. 363-367 ◽  
Author(s):  
P. MARY COTES ◽  
B. A. CROSS
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Adult Female ◽  
Post Partum ◽  
Female Rats ◽  
Milk Secretion ◽  
Growth Increments ◽  
Main Factor

SUMMARY Changes in body weight and food intake were studied for 14 days post partum in primiparous rats. The growth increments in suckled rats with galactophores cut to prevent milk withdrawal and in normally lactating rats were greater than in unsuckled controls. The growth increments in rats with galactophores cut were accompanied by parallel increases in food intake. Injection of 3 i.u. prolactin daily did not reproduce these changes in body weight and food intake in non-suckled rats. The results suggest that the main factor in the extra growth of lactating rats is an increased food intake in excess of the metabolic needs for milk secretion induced by the stimulus of suckling.

Interrelationships between physical and metabolic control of voluntary food intake in fattening, pregnant and lactating mature sheep: a model

1977 ◽  
Vol 24 (1) ◽  
pp. 91-101 ◽  
Author(s):  
J. M. Forbes
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Abdominal Fat ◽  
Metabolizable Energy ◽  
Energy Requirements ◽  
Final Body Weight ◽  
Pregnancy And Lactation ◽  
Endocrine Factors ◽  
Ad Libitum ◽  
Voluntary Food Intake

SUMMARYA model has been developed in which the voluntary food intake of sheep is related directly to metabolizable energy requirements unless physical or endocrine limitations intervene.Although no ‘set point’ for body weight or body fat is incorporated in the model, mature sheep offered food ad libitum are predicted to reach eventually a plateau of body weight due to progressive depression of gut capacity by the increasing volume of abdominal fat. The final body weight is proportional to the digestibility of the diet. During pregnancy and lactation metabolic, physical and endocrine factors interact in such a way as to give predicted patterns of feed intake similar to those observed in practice with several qualities of diet.

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