Effect of Restricted Nutrition on Puberty in the Lamb: Patterns of Tonic Luteinizing Hormone (LH) Secretion and Competency of the LH Surge System*

Foster, Douglas L.; Olster, Deborah H.

doi:10.1210/endo-116-1-375

Cited by 232 publications

(146 citation statements)

References 16 publications

Supporting

Mentioning

133

Contrasting

Unclassified

Order By: Relevance

“…Similar responses have been observed in ewe lambs when puberty is delayed by underfeeding (Foster & Olster, 1985) and in adult rams subjected to changes in food availability (Martin et al, 1990). The frequency of GnRH pulses is the primary signal controlling testicular development (Lincoln, 1979a).…”

Section: Discussionsupporting

confidence: 69%

Effects of dietary zinc deficiency on gonadotrophin secretion and testicular growth in young male sheep

Martin

White²

1992

Reproduction

View full text Add to dashboard Cite

Summary. The hypothesis that the secretion of gonadotrophins would be reduced by zinc deficiency was tested in five groups of four young Merino rams (initial liveweight 22 kg). Four groups were fed ad libitum with diets containing 4, 10, 17 or 27 \ g=m\ g Zn g \ m=-\ 1. The effects of loss of appetite on the deficient diet was controlled by feeding a fifth group (pair-fed control) at a rate of 27 \g=m\g Zn g \ m=-\ 1, but the amount of feed offered was restricted to that eaten voluntarily by the deficient (4 \ g=m\ g Zn g\ m=-\ 1) group. Blood was sampled every 20 min for 32 h on two occasions before the treatments were imposed and 96 days later, at the end of the experiment. The rams were injected with gonadotrophin-releasing hormone (GnRH; 10 ng kg \ m= -\ 1 i.v.) after each serial sampling, and with naloxone (1 mg kg\m=-\ 1 i.v.) 24 h after the end of the final GnRH test.In the group that were fed the diet with the lowest zinc content, the concentration of zinc in blood plasma was reduced to 18% of that in the pair-fed controls (P < 0\m=.\05) and was within the deficient range. The appetite of the deficient rams was half that of the controls fed 27 \g=m\g Zn g\m=-\1 ad libitum and there was no increase in liveweight or testicular diameter during pubertal development. Similar, but smaller, effects were observed in the pair-fed controls. There were no significant differences between pair-fed and deficient groups in the frequency of the luteinizing hormone (LH) pulses or in the concentration of follicle-stimulating hormone (FSH), but the secretion of gonadotrophins was markedly lower in both groups than in the control rams fed ad libitum. The response to GnRH was not affected by treatment, but the increase in LH pulse frequency evoked by naloxone was lower in the deficient animals than in other groups.The animals fed zinc at intermediate rates (10\p=n-\17 \ g=m\ g\ g=m\ \ m=-\ 1) showed similar responses to the controls fed ad libitum.It is concluded that the specific effects of zinc deficiency on testicular function were small. Most of the reduction in testicular growth in rams fed a deficient diet was not specifically related to the trace element, but was due to the fall in energy and protein intake caused by the loss of appetite. This leads to a reduction in the frequency of GnRH pulses secreted by the hypothalamus, and to low rates of gonadotrophin secretion by the pituitary gland.

show abstract

Section: Discussionsupporting

confidence: 69%

Effects of dietary zinc deficiency on gonadotrophin secretion and testicular growth in young male sheep

Martin

White²

1992

Reproduction

View full text Add to dashboard Cite

show abstract

“…In ewe lambs, however, undernutrition impaired gonadotrophin secretion and delayed puberty (Foster & Olster, 1985). Similarly, in wild house mice, food restriction prevents reproductive development in females but not males (Hamilton & Bronson, 1985).…”

Section: Discussionmentioning

confidence: 97%

Delayed puberty caused by hyperthyroidism in ram lambs is not a result of suppression in body growth

Chandrasekhar¹,

D’Occhio²,

Setchell³

1986

Reproduction

View full text Add to dashboard Cite

“…Thus, female lambs undergoing severe food restriction after weaning show significant delays in the initiation of puberty, even a durable blockage of the reproductive function [42]. Refeeding was observed to induce the onset of puberty within a few weeks in ewe lambs whose puberty was previously inhibited by food restriction [41].…”

Section: Characterisation Of the Interrelationships Between Nutritionmentioning

confidence: 98%

Adaptive abilities of the females and sustainability of ruminant livestock systems. A review

Blanc

Bocquier²,

Agabriel

et al. 2006

Anim. Res.

View full text Add to dashboard Cite

-In a systemic approach, the breeder can be considered as the decisional component of the livestock system, whereas animals are usually depicted to be part of its biotechnical component. The animal itself is a biological system whose ability to survive, grow, reproduce and cope with the environnement and livestock practices play a major role in the ability of the livestock system to sustain. In such a conceptual representation of the system, the reproductive females draw a peculiar attention since they determine in a great part the productivity and the durability of the system through their abilities to maintain their own production level (milk production, numeric productivity) and to save their reproductive efficiency (repeated pregnancies and lactations) over years. Considering the animal level and its lifespan, it is clear that the abilities to adapt rely on behavioural and physiological regulatory processes. The study of the biological mechanisms involved in the adaptation to undernutrition is particularly interesting since regulatory processes implied in energy metabolism may interfere directly or indirectly with the reproductive function, and consequently, with the durability of the livestock system. A biological significance of such relationships between nutrition and reproduction is given that they allow the female to be informed about the associated risk of entering a productive process facing the uncertainty of the nutritional context. Although the general mechanisms implied in the ability to adapt to the underfeeding constraint are conserved among ruminants, the thresholds (or priorities) may largely differ according to the breed within the same species. Hence, in order to evaluate the ability of the ruminant livestock systems to perpetuate in hard environments (maintaining their production levels) or to assess sustainable objectives (opening bushy landscapes by increasing grazing pressure), animals' inherent adaptive potentialities have to be well known. Résumé -Capacités adaptatives des femelles et durabilité des systèmes d'élevage. Synthèse bibliographique. Dans une représentation systémique du système d'élevage, l'éleveur incarne la composante décisionnelle du système, tandis que l'animal constitue, avec la ressource, sa composante biotechnique. L'animal lui-même peut être considéré comme un système biologique soumis à un environnement contraignant, dont les aptitudes à survivre, croître, se reproduire et s'adapter jouent un rôle fondamental dans la pérennité du système d'élevage. Les femelles reproductrices tiennent une place particulière dans cette représentation car non seulement elles déterminent une large part de la productivité du système par leur propre niveau de production (production laitière, productivité numérique), mais elles en assurent également sa reproductibilité au cours du temps (investissement reproductif). A l'échelle de l'individu et de sa durée de vie, les modalités d'adaptation reposent sur des processus de régulations comportementales et physiologiques. De tels pro...

show abstract

Effect of Restricted Nutrition on Puberty in the Lamb: Patterns of Tonic Luteinizing Hormone (LH) Secretion and Competency of the LH Surge System*

Cited by 232 publications

References 16 publications

Effects of dietary zinc deficiency on gonadotrophin secretion and testicular growth in young male sheep

Effects of dietary zinc deficiency on gonadotrophin secretion and testicular growth in young male sheep

Delayed puberty caused by hyperthyroidism in ram lambs is not a result of suppression in body growth

Adaptive abilities of the females and sustainability of ruminant livestock systems. A review

Contact Info

Product

Resources

About