The effect of dietary molybdenum and sulphate on sexual activity and plasma progesterone concentrations of ewes

Plessis, Stefan S. du; Niekerk, F.E. Van; Coetzer, W.A.

doi:10.1016/s0921-4488(99)00004-8

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…Therefore, a reduction in the production of androstenedione, as we have reported for TTM doses greater than 5, is likely to limit the production of oestradiol due to substrate limitation. The results of the present study are consistent with an effect of molybdenum-induced copper deficiency on the development of the preovulatory follicle, especially steroid secretion, and would therefore be expected to perturb both behavioural oestrus and ovulation to a varying degree, as has been observed in animals with molybdenum-induced copper responsive subfertility (Phillippo et al 1987, Du Plessis et al 1999a, 1999b. Further, it is well established that ovarian oestradiol plays a key role in controlling gamete transport and in priming the uterus for implantation, so that even if ovulation does occur, fertility rates are likely to be impaired if preovulatory oestradiol production is sub-optimal .…”

Section: Discussionsupporting

confidence: 89%

“…Du Plessis et al (1999a) have also shown that behavioural anoestrus occurs relatively quickly, within 6 weeks, in sheep fed a high molybdenum and sulphur diet, with true anoestrus occurring after a much longer supplementation time in the trial. Du Plessis et al (1999b) also showed that ovaries were reduced in size and have a decreased response to a follicle-stimulating hormone (FSH)-induced superovulation regimen in the molybdenum and sulphur supplemented groups. Whilst molybdenum-induced copper depletion may also have central effects via the hypothalamus-pituitary axis on LH secretion, many of the above 'symptoms' are consistent with reduced ovarian oestradiol secretion.…”

Section: Introductionmentioning

confidence: 99%

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Effect of copper and thiomolybdates on bovine theca cell differentiation in vitro

Kendall¹,

Marsters²,

Guo³

et al. 2006

Journal of Endocrinology

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Subfertility that will respond to appropriate copper supplementation is a widespread problem in the national dairy herd. The aims of this study were to determine the effect of copper and/or copper chelating thiomolybdates on LH-induced differentiation by looking at the effects on androgen production, steroidogenic enzymes (cytochrome P450 17 -hydroxylase and cytochrome P450 side-chain cleavage) and lysyl oxidase mRNA expression in cultured theca cells maintained under serum-free conditions.The effect of thiomolybdates and copper on LH differentiation was investigated by supplementing (ammonium) tetrathiomolybdate to optimum theca cell culture media at 0-100 µg/ml, copper (chloride) at equimolar concentrations (0-51·6 µg/ml) or equimolar combinations of both media. Lysyl oxidase mRNA expression was investigated with semi-quantitative RT-PCR, whilst expression of cytochrome P450 17 -hydroxylase and cytochrome P450 side-chain cleavage mRNA was examined using real time PCR. Both PCRs used bovine specific primers and cell lysates obtained from bovine theca cells cultured for 6 days and in the presence or absence of the 100 µg/ml dose of thiomolybdate and equimolar copper thiomolybdate.Thiomolybdate depressed androstenedione production in a dose-dependent manner at doses greater than 1 µg/ml at 96 h (P<0·05); doses above 20 µg/ml were all greatly reduced at all time points and at 192 h when related to numbers of cells (P<0·001). Copper alone had no effect at physiological doses, but the use of the equimolar copper thiomolybdate reversed the effect of tetrathiomolybdates on androstenedione production at the 20 µg/ml dose. Thiomolybdate supplementation, with and without copper, had no significant effect on the level of lysyl oxidase or cytochrome P450 side-chain cleavage expression. However, cytochrome P450 17 -hydroxylase expression was significantly increased (P<0·05) by tetrathiomolybdate, possibly due to a local regulatory system.In conclusion, these results demonstrate that thiomolybdates can prevent LH-induced differentiation of bovine theca cells in vitro and that these effects can be ameliorated by copper supplementation. Our results also indicate that it is unlikely that the effects of thiomolybdate are mediated at the transcriptional level and further work is required to determine if thiomolybdate exerts its effects through post-translation processing or some other unrelated mechanism. Overall, these data support the hypothesis that copper responsive subfertility results from perturbation of the normal pattern of ovarian steroidogenesis.

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Section: Discussionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Effect of copper and thiomolybdates on bovine theca cell differentiation in vitro

Kendall¹,

Marsters²,

Guo³

et al. 2006

Journal of Endocrinology

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“…In sheep, postnatal lordosis, detected as muscle weakness and ataxia, is also caused by Cu deficiency during gestation (Ashworth and Antipatis, 2001). Du Plessis et al (1999) observed a suppressed estrous behaviour in ewes due to induced secondary Cu deficiency that might be attributed to altered production and/or expression of hormones, such as estrogens and luteinizing hormone (LH) and folliclestimulating hormone (FSH). The percent samples deficient in Cu were in the order of rams>lambs/weaners>lactating >dry>pregnant.…”

Section: Effect Of Physiological Status On Plasma Mineralsmentioning

confidence: 99%

Effects of physiological status and seasonal variation on plasma mineral profile of sheep in Kashmir valley

Dar¹,

Jadhav²,

Dimri³

et al. 2014

Sci. Res. Essays

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Evaluating mineral profile of sheep, belonging to different physiological states and in different seasons, is an important indicator of their nutritional and health status. This is important to prevent health disorders which lead to production and reproductive disturbances. A total of 167 blood samples were collected in four different seasons of the year from sheep having varied physiological demands in Shuhama Alusteng area of Kashmir valley. The plasma macro-minerals such as Ca, P i and Mg were measured using standard kits; while as micro-minerals like Cu, Zn and Fe were estimated using atomic absorption spectrometry. The concentration of Ca was below the critical level during pregnant and lactating periods, and round about the critical level throughout the year. The Mg values were just above the critical concentration in all categories of sheep throughout the year. The concentrations of Cu and Zn were above the critical levels in all categories of sheep especially during the winter season. P i and Fe levels were adequate in all throughout the year. In addition, a good percentage of samples were deficient in one or the other mineral round the year. The results suggest that sheep in the study area should be supplemented with Ca and Mg round the year; Cu and Zn during spring, summer and autumn seasons. Also, the influence of local agro-geo-climatic conditions plus mineral interactions involving greater sample size must be studied prior to attempting the formulation of area specific mineral supplement(s). Further, the dosage should be recommended as per the physiological need of an animal.

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Assessing the needs of sheep for trace elements

Suttle¹

2005

In Practice

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NO progress can be made in assessing the trace element needs of sheep without first addressing the question of ‘status’. This term means different things to different people but, for the purposes of this discussion, implies the ranking of an individual or flock, with respect to the adequacy of trace element supply in relation to need, across a spectrum ranging from gross deprivation to poisoning. Various indices of status exist for each element, but none are completely reliable. This article outlines their general shortcomings, draws attention to specific failings and provides honest guides to interpretation that should improve the precision of diagnosing trace element disorders and assessing the status of sheep.

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The effect of dietary molybdenum and sulphate on sexual activity and plasma progesterone concentrations of ewes

Cited by 3 publications

References 13 publications

Effect of copper and thiomolybdates on bovine theca cell differentiation in vitro

Effect of copper and thiomolybdates on bovine theca cell differentiation in vitro

Effects of physiological status and seasonal variation on plasma mineral profile of sheep in Kashmir valley

Assessing the needs of sheep for trace elements

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