Jean-Marie Godeau

Experimental production of hypocalcemia by EDTA infusion in calves: a critical appraisal assessed from the profile of blood chemicals and enzymes.

Physiological studies of the effects of Ca2+ withdrawal using Na2EDTA have been conducted with the prior basic assumption that Na2EDTA-specific direct or indirect effects on the functions under study were negligible. The present study aimed at providing unequivocal confirmation of such assumption by establishing the pattern of response of blood constituents to intravenous infusions of Na2EDTA in calves. Na2EDTA infusion in calves allowed effective chelation of blood Ca2+, leading to a progressive hypocalcemia. Magnesium levels remained constant and concentrations of other ions (Na+, K+, Pi, H+, HCO3-), although significantly altered (P < or = 0.0001), remained within the normal range. Comparison of enzymes, urea, and creatinine changes precluded renal, hepatic, or muscular parenchymatous damages as being the cause of dysfunctions in the context of Na2EDTA-induced hypocalcemia. It was not possible, however, to standardize the Na2EDTA infusion characteristics (flow, volume) to obtain previsible Ca2+ decay in different animals. Conversely, monitoring of systemic arterial pressure (SAP) offered a precious tool to estimate the degree of hypocalcemia reached. Infusion rate must, therefore, be manipulated using careful on-line monitoring of SAP to obtain an experimental range of Ca2+ as large as possible. It was concluded that physiological data collected during Na2EDTA perfusions can be reliably discussed in terms of Ca2+ dependence rather than in terms of either Na2EDTA toxicity, electrolytes maladjustment, acid-base imbalance, impaired blood oxygenation, or hepatic, renal, myocardic, or skeletal muscle damages.

Effects of late pregnancy and early lactation on renal urea handling in Corriedale ewes

The aim of the study was to investigate the changes in renal function in late pregnant and early lactating Corriedale ewes. Compared with the non-productive state, plasma urea concentration was increased by 67% during pregnancy, whereas it decreased by 36% during lactation. Urine flow, urea clearance, renal plasma flow and glomerular filtration rate were significantly reduced (P < 0.05) during both late pregnancy and early lactation. Filtered load of urea and the amount of urea eliminated were significantly reduced (P < 0.05) only in lactating ewes. No changes were noted in the fractional excretion of urea, the filtration fraction and the urine osmolality during both late pregnancy and early lactation. It was concluded that, as in other breeds, Corriedale ewes can adapt to increased nitrogen requirements during late pregnancy, and especially during early lactation, by increasing the renal conservation of urea. Unlike other breeds, however, Corriedale ewes restrict the urine urea losses mainly by reducing renal plasma flow and glomerular filtration rate, without any modification of the tubular reabsorption of urea during both late pregnancy and early lactation.

Effect of short-chain fructooligosaccharide-enriched energy-restricted diet on weight loss and serum haptoglobin concentration in Beagle dogs

The effects of the dietary inclusion of two levels of short-chain fructooligosaccharides (sc-FOS) on weight loss, biochemical parameters and serum haptoglobin concentration were investigated in twelve experimental obese Beagle dogs. Dogs were randomised into two groups and submitted to a weight loss program (WLP): the control group (C) received a commercial energy-restricted high-protein diet containing 1 % DM sc-FOS, whereas the test group (T) received the same diet enriched with sc-FOS to attain a 3 % DM content. Body weight (BW) and body condition score were weekly assessed in each dog and blood was collected before and after WLP to measure total plasma cholesterol (CHOL), TAG, NEFA, glucose (GLUC), insulin, serum leptin and haptoglobin. Groups showed similar BW and blood parameters before treatment. When values before and after treatment of the dogs were compared, significant reductions were observed for all parameters, with the exception of NEFA and GLUC. However, when these reductions were compared between C and T groups, significant differences were detected only for haptoglobin (T before v. T after: 1545 v. 605 mg/l, P = 0.03; C before v. C after: 1635 v. 1400 mg/l, P = NS). Positive correlations between haptoglobin and CHOL and between haptoglobin and TAG were observed before but not after WLP. In conclusion, feeding obese dogs with the energy-restricted diet caused significant weight loss and reduction of blood parameters, irrespective of the sc-FOS content included. However, serum haptoglobin level, and the subclinical inflammatory condition associated with it, was significantly lowered in the T but not in the C group.