Is mammary output capacity limiting to lactational performance in mice?

1996 ◽  
Vol 199 (2) ◽  
pp. 337-349 ◽  
Author(s):  
K A Hammond ◽  
K C Lloyd ◽  
J Diamond
Keyword(s):  
Food Intake ◽  
Litter Size ◽  
Mammary Glands ◽  
High Food ◽  
Uptake Capacity ◽  
Start Up ◽  
Lactational Performance ◽  
Teat Number ◽  
Size Controlled ◽  
Stimulation Of

Using lactation in mice as a model, we sought to determine whether ceilings on sustained energy expenditure reside in the capacities of energy-acquiring and input organs (such as the intestine) or of energy-expending and output organs (such as the mammary glands). To distinguish between these possibilities experimentally, we surgically varied the teat number of lactating mother mice while simultaneously varying their litter size. The energy burden on each teat (i.e. the pup/teat ratio) could thus be varied independently of the energy burden (i.e. litter size) on the mother herself or on her intestine. At each teat number, pup mass proved to be maximal at intermediate litter sizes. At a given pup/teat ratio, mothers with five teats weaned pups no larger than the pups of normal (10-teat) mothers, even though the total energy burden on the former mothers was only half as large. Mothers with only two teats could not wean any pups. Litter size controlled maternal food intake, which in turn controlled intestinal mass and nutrient uptake capacity. Disproportionately high food intake for the smallest litters appears to reflect capital start-up costs of lactation. Pup mass is evidently limited by inadequate suckling stimulation of mammary glands.

Genetic effects on maternal performance and litter pre-weaning and post-weaning traits in rabbits

1984 ◽  
Vol 38 (2) ◽  
pp. 293-300 ◽  
Author(s):  
S. Lukefahr ◽  
W. D. Hohenboken ◽  
P. R. Cheeke ◽  
N. M. Patton
Keyword(s):  
Body Weight ◽  
New Zealand ◽  
Food Intake ◽  
Litter Size ◽  
Total Mortality ◽  
Litter Traits ◽  
Mortality Incidence ◽  
Teat Number ◽  
Maternal Performance ◽  
Daily Gain

AbstrtactFlemish Giant (FG) and New Zealand White (NZW) purebreds and terminal crossbreds (TX) (Flemish Giant sires × Florida White-New Zealand White dams) were evaluated during a 10-month period for maternal and litter pre-weaning and post-weaning performance. For the doe traits studied, teat number was greatest and litter interval was shortest, while body weight at breeding age (154 days), litter weight at 21 days and day 1 to 21 food intake were lowest for crossbred does. These traits were similar for pure doe groups, with the exception of body weight, for which FG does were heavier. For the preweaning litter traits examined (no. = 101 litters), litter size born was smallest in the TX group (the purebred groups being similar) and was largest at weaning (28 days) for NZW. Proportion of kits born alive was lowest in FG litters, while the NZW and TX groups were comparable. Litter and average birth and weaning weights, litter daily gain, and doe and litter food intake (1 to 28 days) were all highest in FG litters and lowest in TX litters. Repeatability estimates (t) were low (t < 0·05) for litter size and birth weight traits, and were moderate to high (0·18 < t < 0·58) for the remaining maternally influenced characters. For the post-weaning litter traits studied (no. = 86 litters), NZW litters were larger in number and heavier at market age (56 days), and consumed more food from 28 to 56 days than FG and TX litters. Purebred FG litters, however, had heavier average market weights per rabbit, while purebred NZW and TX litters were similar. Mortality due to respiratory disease was higher in FG litters than in NZW and TX litters. Total mortality incidence was lowest in the TX group.

The Effect of Food Intake During Lactation and Early Pregnancy on Plasma Progesterone Concentrations and Prolificacy in Multiparous sows

1988 ◽  
Vol 1988 ◽  
pp. 55-55
Author(s):  
G.R. Prime ◽  
M.A. Varley ◽  
H.W. Symonds
Keyword(s):  
Food Intake ◽  
Litter Size ◽  
Early Pregnancy ◽  
High Food ◽  
Limited Evidence ◽  
Embryo Survival ◽  
Plasma Progesterone ◽  
Effect Of Food ◽  
Low Levels ◽  
High Level

High food intake in early pregnancy resulted in increased prenatal mortality and reduced subsequent litter size in many studies using gilts (den Hartog and Van Kempen, 1980). With multiparous sows there is generally no difference in the rate of embryo survival or litter size with high feeding in early pregnancy (Toplis et al, 1983, Dyck & Cole, 1986).Limited evidence suggests that sows fed low levels in lactation and then a high level early in the following pregnancy may show increased rates of embryo mortality (Pike and Boaz, 1972; Hughes et al, 1984). The effect of high feeding may be due to low plasma progesterone concentrations (Hughes et al 1984; Dyck et al, 1980) in early pregnancy which may be associated with reduced embryo survival and litter size.This study was designed to investigate the effects of high or low feed intake in lactation and early pregnancy on plasma progesterone concentrations in early pregnancy and subsequent litter size using multiparous sows.

Melatonin Modulates Lactation by Regulating Prolactin Secretion Via Tuberoinfundibular Dopaminergic Neurons in the Hypothalamus- Pituitary System

2020 ◽  
Vol 21 (8) ◽  
pp. 744-750 ◽  
Author(s):  
Hongyang Li ◽  
JingyaWei ◽  
Fengtao Ma ◽  
Qiang Shan ◽  
Duo Gao ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Pituitary Gland ◽  
Antioxidant Capacity ◽  
Dopaminergic Neurons ◽  
Growth And Development ◽  
Endocrine System ◽  
Mammary Glands ◽  
Prolactin Secretion ◽  
The Body ◽  
Stimulation Of

In-depth studies have identified many hormones important for controlling mammary growth and maintaining lactation. One of these is melatonin, which is synthesized and secreted by the pineal gland to regulate circadian rhythms, improve antioxidant capacity, and enhance immunity. Prolactin is secreted by the pituitary gland and is associated with the growth and development of mammary glands as well as initiation and maintenance of lactation. The hypothalamus-pituitary system, the most important endocrine system in the body, regulates prolactin secretion mainly through dopamine released from tuberoinfundibular dopaminergic neurons. This review provides a reference for further study and describes the regulation of lactation and prolactin secretion by melatonin, primarily via the protection and stimulation of tuberoinfundibular dopaminergic neurons.

Stimulation of food intake following opiate agonists in rats but not hamsters

1983 ◽  
Vol 81 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Martin T. Lowy ◽  
G. K. W. Yim
Keyword(s):  
Food Intake ◽  
Stimulation Of

NEURAL FACTORS IN THE MAINTENANCE OF LACTATION IN THE RAT

1967 ◽  
Vol 38 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. EDWARDSON ◽  
J. T. EAYRS
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Quantitative Relationship ◽  
Mammary Tissue ◽  
Single Pair ◽  
Endocrine Response ◽  
Peripheral Innervation ◽  
Lactational Performance ◽  
Neural Factors

SUMMARY The role of the peripheral innervation of mammary tissue in the maintenance of lactation has been investigated by the procedure of selective thelectomy combined with denervation of the posterior thoracic nipples. When suckling is restricted to a single pair of nipples bilateral transection of the three adjacent nerves supplying a nipple arrests lactation completely; partial denervation is associated with a reduced level of lactational performance which is directly related to the concentration of the residual innervation. Increase in litter size is associated with an overall increase in milk-yield up to a limit beyond which the addition of further young to the litter is without effect. It is inferred that there is a quantitative relationship between the neural stimulus of suckling and the endocrine response of the hypothalamopituitary system.

Enhanced food intake after stimulation of hypothalamic P2Y1receptors in rats: modulation of feeding behaviour by extracellular nucleotides

2006 ◽  
Vol 24 (7) ◽  
pp. 2049-2056 ◽  
Author(s):  
Holger Kittner ◽  
Heike Franke ◽  
Julia I. Harsch ◽  
Ibrahim M. El-Ashmawy ◽  
Bertholt Seidel ◽  
...  
Keyword(s):  
Food Intake ◽  
Feeding Behaviour ◽  
Extracellular Nucleotides ◽  
Stimulation Of

Adrenergic Stimulation of the Rat Diencephalon and its Effect on Food Intake and Hoarding Activity

1970 ◽  
Vol 22 (2) ◽  
pp. 125-132 ◽  
Author(s):  
J. E. Blundell ◽  
L. J. Herberg
Keyword(s):  
Electrical Stimulation ◽  
Food Intake ◽  
Food Deprivation ◽  
Lateral Hypothalamus ◽  
Adrenergic Stimulation ◽  
Feeding Mechanism ◽  
Stimulation Of ◽  
Nutritional Depletion

The diencephalic area most sensitive to microinjections of noradrenaline lay outside the area of the lateral hypothalamus in which feeding can be produced by electrical stimulation. Injection of either area, including injections that caused increased feeding, failed to have any effect on hoarding activity. Since hoarding can be elicited both by food deprivation and by electrical stimulation of the lateral hypothalamus, these findings indicate biochemical, anatomical and motivational differences between the central feeding mechanism sensitive to adrenergic stimulation, and that responding to electrical stimulation or nutritional depletion. The former mechanism may be disinhibitory; the latter, excitatory.

Limits to sustained energy intake

2001 ◽  
Vol 204 (11) ◽  
pp. 1947-1956 ◽  
Author(s):  
M. S. Johnson ◽  
S. C. Thomson ◽  
J. R. Speakman
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Litter Size ◽  
Resting Metabolic Rate ◽  
Control Group ◽  
Lower Mass ◽  
Daily Food Intake ◽  
Energy Demands ◽  
Daily Food ◽  
Pregnancy And Lactation

SUMMARYTo determine whether mice were limited in their capacity to absorb energy during late lactation, we attempted to increase the energy burden experienced by a group of female mice during late lactation by mating them at the postpartum oestrus, hence combining the energy demands of pregnancy and lactation. These experimental mice were therefore concurrently pregnant and lactating in their first lactation, and were followed through a normal second lactation. In a control group, females also underwent two lactations but sequentially, with the second mating after the first litter had been weaned. Maternal mass and food intake were measured throughout the first lactation, second pregnancy and second lactation. Maternal resting metabolic rate (RMR) was measured prior to the first mating and then at the peak of both the first and second lactations. Litter size and litter mass were also measured throughout both lactations. In the first lactation, experimental mice had a lower mass-independent RMR (F1,88=5.15, P=0.026) and raised significantly heavier pups (t=2.77, d.f.=32, P=0.0093) than the control mice. Experimental mice delayed implantation at the start of the second pregnancy. The extent of the delay was positively related to litter size during the first lactation (F1,19=4.58, P=0.046) and negatively related to mean pup mass (F1,19=5.78, P=0.027) in the first lactation. In the second lactation, the experimental mice gave birth to more (t=2.75, d.f.=38, P=0.0092) and lighter (t=−5.01, d.f.=38, P&lt;0.0001) pups than did the controls in their second lactation. Maternal asymptotic daily food intake of control mice in the second lactation was significantly higher (t=−4.39, d.f.=37, P=0.0001) than that of the experimental mice and higher than that of controls during their first lactation. Despite the added burden on the experimental females during their first lactation, there was no increase in their food intake, which suggested that they might be limited by their capacity to absorb energy. However, control females appeared to be capable of increasing their asymptotic food intake beyond the supposed limits estimated previously, suggesting that the previously established limit was not a fixed central limitation on food intake. As RMR increased in parallel with the increase in food intake during the second lactation of control mice, the sustained energy intake remained at around 7.0×RMR.

Brain oxytocin receptors mediate corticotropin-releasing hormone-induced anorexia

1991 ◽  
Vol 260 (2) ◽  
pp. R448-R452 ◽  
Author(s):  
B. R. Olson ◽  
M. D. Drutarosky ◽  
E. M. Stricker ◽  
J. G. Verbalis
Keyword(s):  
Food Intake ◽  
Adrenocorticotropic Hormone ◽  
Central Administration ◽  
Corticotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Oxytocin Receptors ◽  
Artificial Cerebrospinal Fluid ◽  
Pituitary Secretion ◽  
Inhibit Food Intake ◽  
Stimulation Of

Central administration of corticotropin-releasing hormone (CRH) is known to inhibit food intake and stimulate pituitary oxytocin (OT) secretion in rats. These experiments addressed the possibility that the inhibition of food intake that follows central CRH administration is mediated through oxytocinergic pathways. Male food-deprived rats, with stable baseline food intakes after intracerebroventricular (icv) injections of artificial cerebrospinal fluid, received 150 pmol of CRH icv. Food intake was inhibited by 62 +/- 5% during a 90-min test period. Pretreatment with 9 nmol of the OT antagonist [d(CH2)5, Tyr(Me)2, Orn8]vasotocin icv completely eliminated the inhibition of food intake produced by icv CRH. In contrast, pretreatment with the OT-receptor antagonist did not significantly alter pituitary secretion of adrenocorticotropic hormone and OT stimulated by icv CRH. The results of these experiments implicate OT as a possible central mediator of CRH-induced anorexias in rats, particularly those that are accompanied by stimulation of neurohypophysial OT secretion.

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