Expression of obese mRNA in genetically lean and fat selection lines of sheep

Kumar, B. V. Sunil; Francis, S. M.; Suttie, J. M.; Thompson, Matthew

doi:10.1016/s0305-0491(98)10041-x

Cited by 46 publications

(33 citation statements)

References 28 publications

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“…A similar nutritional effect was reported in cattle (Chilliard et al 1998a, Delavaud et al 1999, humans (Dubuc et al 1998) and rodents (Ahima et al 1996). Moreover, recent studies in ruminants showed that 7 days of underfeeding on a diet providing 22% of energy requirements (Bocquier et al 1998) or a 48 h fast (Kumar et al 1998, Tsuchiya et al 1998 had negative effects on adipose tissue leptin mRNA amount, thus suggesting a pre-translational regulation. The mechanism of this regulation is unknown in ruminant species, but could be due to an increase in the sympathetic nervous system activity in white adipose tissue, as was shown in mice (Trayhurn et al 1998) and is suggested by the negative effect of a beta-agonist infusion on cattle plasma leptin (Chilliard et al 1998a).…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, mRNA studies demonstrated that the ruminant leptin gene is specifically expressed in adipose tissues (Dyer et al 1997b, Ji et al 1998, Tsuchiya et al 1998 and is related to feeding level (Bocquier et al 1998, Kumar et al 1998. Leptin gene expression is also modulated by daylength in sheep, independently of food intake, adiposity and reproductive activity (Bocquier et al 1998).…”

Section: Introductionmentioning

confidence: 99%

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Plasma leptin determination in ruminants: effect of nutritional status and body fatness on plasma leptin concentration assessed by a specific RIA in sheep

Delavaud

Bocquier²,

Chilliard

et al. 2000

Journal of Endocrinology

354

222

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A specific leptin RIA was developed to assess concentrations of leptin in ovine plasma, and was shown to be efficient with bovine and caprine plasma. A specific, high-affinity antibody was generated against recombinant ovine leptin which, when used in a competitive leptin RIA, provided valid estimates of linearity (r=+0·989-0·998), recovery (102%), repeatability (13%) and limit of sensitivity (0·83 ng/ml for 100 µl sample size). Serial dilutions of five ovine, bovine or caprine plasma samples showed good linearity and parallelism with the recombinant ovine leptin standard curve. A comparison of this RIA was made with a commercial 'multi-species' RIA kit using 56 ovine plasma samples. Major differences were found in assay sensitivity. Non-lactating, non-pregnant, ovariectomized ewes were fed a ration for 65 days which provided 90 9% (control; n=12) or 39 2% of maintenance energy requirements (underfed; n=16) in order to analyse the respective effects of body fatness (estimated by either an in vivo dilution technique or body condition scoring) and of nutritional status on plasma leptin concentration. There was a significant positive correlation between body fatness or body condition score and plasma leptin levels (r=+0·68, P<0·001 or r=+0·72, P<0·001 respectively). When concentrations of leptin were assessed over time, underfed ewes exhibited a dramatic reduction in plasma leptin values ( 56%, P<0·001). These data provide strong evidence that, in sheep, the variations in plasma concentrations of leptin are related to variations in body fatness (35%) and, to a lesser extent, in nutritional status (17%).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plasma leptin determination in ruminants: effect of nutritional status and body fatness on plasma leptin concentration assessed by a specific RIA in sheep

Delavaud

Bocquier²,

Chilliard

et al. 2000

Journal of Endocrinology

354

222

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“…Leptin will also activate POMC neurons to inhibit feed intake. In ruminants, leptin gene expression and immunohistochemistry indicate that leptin is synthesized by the fat cell (Dyer et al, 1997;Kumar et al, 1998;Daniel et al, 2003). Circulating leptin concentrations are episodic in nature and are increased by obesity and decreased by fasting, though there were no apparent photoperiod effects on plasma leptin concentrations (Kumar et al, 1998;Marie et al, 2001;Daniel et al, 2002;Ehrhardt et al, 2003;Altmann et al, 2005;Chilliard et al, 2005;Delavaud et al, 2007).…”

Section: Leptinmentioning

confidence: 99%

Selected hormonal and neurotransmitter mechanisms regulating feed intake in sheep

Sartin

Daniel

Whitlock

et al. 2010

Animal

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Appetite control is a major issue in normal growth and in suboptimal growth performance settings. A number of hormones, in particular leptin, activate or inhibit orexigenic or anorexigenic neurotransmitters within the arcuate nucleus of the hypothalamus, where feed intake regulation is integrated. Examples of appetite regulatory neurotransmitters are the stimulatory neurotransmitters neuropeptide Y (NPY), agouti-related protein (AgRP), orexin and melanin-concentrating hormone and the inhibitory neurotransmitter, melanocyte-stimulating hormone (MSH). Examination of messenger RNA (using in situ hybridization and realtime PCR) and proteins (using immunohistochemistry) for these neurotransmitters in ruminants has indicated that physiological regulation occurs in response to fasting for several of these critical genes and proteins, especially AgRP and NPY. Moreover, intracerebroventricular injection of each of the four stimulatory neurotransmitters can increase feed intake in sheep and may also regulate either growth hormone, luteinizing hormone, cortisol or other hormones. In contrast, both leptin and MSH are inhibitory to feed intake in ruminants. Interestingly, the natural melanocortin-4 receptor (MC4R) antagonist, AgRP, as well as NPY can prevent the inhibition of feed intake after injection of endotoxin (to model disease suppression of appetite). Thus, knowledge of the mechanisms regulating feed intake in the hypothalamus may lead to mechanisms to increase feed intake in normal growing animals and prevent the wasting effects of severe disease in animals. Keywords: appetite, neuropeptide Y, proopiomelanocortin, leptin, sheep ImplicationsAppetite control by the brain is a critical component of the normal growth and development process as well as of major importance for reproduction. From an understanding of how these mechanisms function, we can develop specific protocols to support appetite in circumstances where feed intake is compromised. For example, development of a melanocortin-4 receptor antagonist that can cross the blood-brain barrier provides the opportunity to increase feed intake in normal animals, as well as to prevent the reduction in feed intake and perhaps body mass wasting in disease conditions. Other areas to consider might be early lactation or in metabolic disease circumstances. Thus, the study of brain control of appetite could have a major impact on improved growth and minimizing losses due to disease or other external stresses. IntroductionAppetite control is a complex process whereby multiple stimulatory and inhibitory inputs are integrated in the hypothalamus to yield an increase or decrease in feed intake. Initial lesioning studies in rodents determined a critical role for the arcuate nucleus (ARC) and ventromedial nucleus (VMN) in the control of appetite. Similar studies of lesions to the paraventricular nucleus (PVN) caused hyperphagia, while lesions of the lateral hypothalamic area (LHA) produced anorexia. These studies have been expanded upon to provide a current concept whereby th...

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“…Research data from swine (Robert et al 1998;Ramsay et al 1998), sheep (Boquier et al 1998Kumar et al 1998), and cattle (Delavaud et al 2002;Ren et al 2002;Geary et al 2003) indicate that plasma and serum leptin concentrations and tissue mRNA levels are highly correlated with intake, carcass quality as well as adipose tissue mass. For instance, in pigs, Robert et al (1998) reported a positive association between leptin mRNA levels and backfat thickness.…”

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confidence: 99%

Association of a single nucleotide polymorphism in the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition

Nkrumah¹,

Li²,

Basarab³

et al. 2004

Can. J. Anim. Sci.

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S. S. 2004. Association of a single nucleotide polymorphism in the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition. Can. J. Anim. Sci. 84: 211-219. Leptin is a 16-kDa-hormone product of the obese gene synthesized and expressed predominantly by adipose tissues, which has been shown to play major roles in the regulation of body weight, feed intake, energy balance, fertility, and immune system functions. We report an investigation into the association of a previously identified cytosine to thymine missense mutation in exon 2 of the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition in five genetic selection lines of a commercial population of beef cattle. Differences among genotypes in growth, feed intake and feed efficiency were not significant (P > 0.10) though steers homozygous for the thymine allele had positive residual feed intake (i.e., consumed more feed than expected) (+ 0.19 kg d -1 ) whilst steers homozygous for the cytosine allele had negative residual feed intake (-0.18 kg d -1 ). Steers carrying the thymine allele had a higher rate of gain in ultrasound backfat (P = 0.02), ultrasound backfat thickness (P = 0.06), higher carcass grade fat (backfat) (P = 0.005), lower yield grade (P = 0.01) and lower lean meat yield (P = 0.007). The thymine allele also tended to be associated with higher loin subcutaneous fat (P = 0.07) and was associated with higher brisket subcutaneous fat (P = 0.01), and brisket body cavity fat (P = 0.0001). No associations were found among the different genotypes and real-time ultrasound marbling, ultrasound longissimus thoracis area, carcass marbling and carcass longissimus thoracis area (P > 0.10). Our results show that animals carrying the thymine allele versus the cytosine allele may produce carcasses with poorer grades and lower lean meat yields but do not differ in carcass marbling or other fat depots.Key words: Beef cattle, leptin, feed intake, carcass merit Nkrumah, J. D., Li, C., Basarab, J. B., Guercio, S., Meng, Y., Murdoch, B., Hansen, C. et Moore, S. S. 2004. Association du polymorphisme d'un nucléotide du gène de la leptine bovine à la prise alimentaire, à la valorisation des aliments, à la croissance, aux habitudes alimentaires, à la qualité de la carcasse et à la composition corporelle. Can. J. Anim. Sci. 84: 211-219. La leptine est un dérivé hormonal 16-kDa du gène de l'obésité synthétisé et principalement exprimé par les tissus adipeux. On sait qu'elle joue un rôle important dans la régulation du poids, la prise d'aliments, le bilan énergétique, la fécondité et les fonctions du système immun. Les auteurs ont étudié l'association d'une mutation faux-sens entre la cytosine et la thymine rapportée antérieurement dans la partie exon 2 du gène de la leptine bovine avec la prise alimentaire, la valorisation des aliments, la croissance, les habitudes alimentaires, la qualité de la carcasse et la composition corporelle de cinq lignées d'...

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Expression of obese mRNA in genetically lean and fat selection lines of sheep

Cited by 46 publications

References 28 publications

Plasma leptin determination in ruminants: effect of nutritional status and body fatness on plasma leptin concentration assessed by a specific RIA in sheep

Plasma leptin determination in ruminants: effect of nutritional status and body fatness on plasma leptin concentration assessed by a specific RIA in sheep

Selected hormonal and neurotransmitter mechanisms regulating feed intake in sheep

Association of a single nucleotide polymorphism in the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition

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