The metabolism in mammalian is regulated by multiple levels of hormone action, with complex feedback and control mechanisms. The somatotropic axis, primarily consisting of growth hormone, insulin-like growth factors (-I and -II), their associated carrier proteins (GHBP and IGFBPs), and receptors, plays a key role in the control of the regulation of metabolism and physiological process. Among this axis, other hormones like insulin, leptine, glucocorticoïds or thyroid hormones are involved in this mechanism by modulating GH and/or IGF-I synthesis and availability. In the present instance, this review summarizes recent findings and the complexity of the regulation of the metabolism by the growth hormone (GH)-insulin-like growth factor (IGF) axis using different examples: special nutritional situations, use of growth promoters (including hormones and hormone analogs such as bST, corticoids, beta-agonists) and particular physiological status (genetic potential, puberty, growth alteration, ….). Feed restriction or postpartum negative energy balance leads to elevated GH and IGFBP-2 secretion, but it reduces hepatic GH receptor (GHR) number and plasma levels of IGF-I and IGFBP-3. Distribution of glucogenic compounds to these animals prevents alterations of the somatotropic axis. GH treatment in animals leads to up-regulation of GH-receptor, increases synthesis and plasma concentrations of IGF-I and IGFBP-3 whereas concentrations of IGFBP-2 decrease; this may lead to increased availability of IGF-I at target tissues. These endocrine interactions, together with metabolic changes, leads to increased protein anabolism, reduced fat deposition, and enhanced growth rate. However, GH treatment seems to differently altered IGFBP-2 and IGFBP-3 mRNA levels in mammary tissue than in hepatic tissue. Similar alterations of somatotropic axis is observed in finishing bulls treated with dexamethasone esters while betaagonist administration reduces IGF-I and IGFBP-3 synthesis and stimulates IGFBP-2 production. Numerous genetic mutations are reported for molecules of somatotropic axis. Some of them are directly related with animal performances, endogenous hormonal synthesis and metabolism. Puberty is another important physiological period characterised by a sharp increase of IGF-I and IGFBP-3 levels and decrease of IGFBP-2 independently to steroids production. In the bovine species, a significant correlation seems to exist between GH response to GHRH stimulation or IGF-I/IGFBPs status and animal metabolism. However, in pig, whereas no differences are observed in GH secretion parameters, IGF-I and IGFBP-3 levels in retarded growth piglets are remarkable lower than in normal weight animals. In this cases, an altered responsiveness of hepatic GH receptor is suspected. The physiological mechanisms of metabolism remains fairly understood in farm animals. However, with the development of new analytical methods, particularly the IGFBPs quantification, advances in research of the somatotropic axis will improve our understanding of the normal anim...

Dialysis patients exhibit an inverse, L- or U-shaped association between blood pressure and mortality risk, in contrast to the linear association in the general population. We prospectively studied 9333 hemodialysis patients in France, aiming to analyze associations between predialysis systolic, diastolic, and pulse pressure with all-cause mortality, cardiovascular mortality, and nonfatal cardiovascular endpoints for a median follow-up of 548 days. Blood pressure components were tested against outcomes in time-varying covariate linear and fractional polynomial Cox models. Changes throughout follow-up were analyzed with a joint model including both the time-varying covariate of sequential blood pressure and its slope over time. A U-shaped association of systolic blood pressure was found with all-cause mortality and of both systolic and diastolic blood pressure with cardiovascular mortality. There was an L-shaped association of diastolic blood pressure with all-cause mortality. The lowest hazard ratio of all-cause mortality was observed for a systolic blood pressure of 165 mm Hg, and of cardiovascular mortality for systolic/diastolic pressures of 157/90 mm Hg, substantially higher than currently recommended values for the general population. The 95% lower confidence interval was approximately 135/70 mm Hg. We found no significant correlation for either systolic, diastolic, or pulse pressure with myocardial infarction or nontraumatic amputations, but there were significant positive associations between systolic and pulse pressure with stroke (per 10-mm Hg increase: hazard ratios 1.15, 95% confidence interval 1.07 and 1.23; and 1.20, 1.11 and 1.31, respectively). Thus, whereas high pre-dialysis blood pressure is associated with stroke risk, low pre-dialysis blood pressure may be both harmful and a proxy for comorbid conditions leading to premature death.

In order to evaluate milking ability in dromedary camels, 124 milk flow curves were registered during morning milking of 20 dairy Maghrebi dromedary camels. Animals were in lactations 1-8, were 6-19 years old and were 4-15 months of their current lactation. Milk flow curves were recorded using an electronic milk flow meter (Lactocorder®). Milk flow curves were classified in three typical patterns: type 1 represents curves with one high and short peak of milk flow; type 2 represents curves with a moderate mean milk flow rate during a large plateau phase; and type 3 represents curves with lower mean milk flow rate and a relatively longer milking duration. The ratio of the different milk flow patterns in the population evaluated was 40:38:22% for types 1, 2 and 3, respectively. The highest milk yield per milking, average and peak milk flow were observed in camels with type 1 curves (4·24 kg, 1·49 and 3·54 kg/min, respectively) followed by type 2 animals (3·30 kg, 1·12 and 2·12 kg/min, respectively) and lastly type 3 curves (2·34 kg, 0·65 and 1·23 kg/min, respectively). This study confirmed that a major proportion of dromedary camels have a suitable machine milking ability. Nevertheless, our results suggest that pre-stimulation and improving the milking process may improve milking efficiency and guarantee a more complete and rapid emptying of the udder.

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Dromedary camel husbandry has recently been evolving towards a semi-intensive system, due to the changes in use of the animal and the settlement of nomadic populations. Captivity could restrict its social activities, limiting the expression of various behavioural needs and causing the manifestation of stereotypy. The aims of this trial were, firstly, to identify and describe some stereotypical behaviours in captive male dromedary camels used for artificial insemination and, secondly, to study the effects on them of the following husbandry management systems: i) housing in single boxes for 24 hours (H24), ii) housing in single boxes for 23 hours with one hour free in the paddock (H23), and iii) housing in single boxes for 22 hours 30 min with 1 h of paddock time and 30 min exposure to a female camel herd (ExF). Every day, the camels were filmed in their single box in the morning for 30 minutes to record their behavioural activities and a focal animal sampling ethogram was filled in. In this study, male camels showed both oral and locomotor stereotypy most frequently when the bulls were reared in H24. Overall, this preliminary study is a starting point in the identification of stereotypies in male camels, reporting the positive effects of spending one hour outdoor and of social interaction with females.