Training-induced modifications of circadian rhythmicity of peroxidative parameters in horses.

The aim of this study was to evaluate the daily rhythms of peroxidative parameters in untrained and trained horses. Blood samples were collected every 4 h for a 48-h period for the determination of reactive oxygen metabolites test (d-ROMs), antioxidant barrier (Oxy-ads), thiol antioxidant barrier (SHp) and lipid peroxidation (LPO). Two-way anova showed a significant effect of time of day on all parameters studied, except on LPO. Higher values of Oxy-ads and SHp were observed in trained horses during both days of monitoring (p < 0.01). All studied parameters, except for LPO, showed robust daily rhythms. Their acrophases occurred during the day in untrained horses and in the evening in trained horses. Our results showed that training increases antioxidative capacity and demonstrated that the daily rhythms of antioxidative parameters can be modified by training.

Electrophoretic serum protein fraction profile during the different physiological phases in Comisana ewes.

The aim of this study was to evaluate the influence of different physiological phases on serum total proteins and their fractions of ten Comisana ewes housed in Mediterranean area. From each animal, blood samples were collected at different physiological phases: late pregnancy, post-partum, early, mid-, end lactation and dry period. On all samples serum total proteins were determined by the biuret method, and albumin, α-globulins, ß(1) -globulins, ß(2) -globulins and γ-globulins concentrations were assessed using an automated system. One-way repeated measures analysis of variance was applied to determine the significant effect of different physiological phases on the parameters studied. During the late pregnancy and post-partum, total proteins, ß1- and ß2-globulins and γ-globulins showed the highest values. Starting from post-partum, α-globulins increased to reach their peaks in mid-lactation. Early lactation was characterized by low γ-globulins values. The increase in serum albumin concentration and the drop in some globulin fractions determined the significant increase in albumin/globulin ratio. The obtained results contributed to improve the knowledge on electrophoretic profile during the different physiological phases in ewes, confirming that pregnancy and lactation periods affect the protein metabolism. Particularly, serum protein fractions pattern could give information about dehydration, plasma volume expansion and hepatic function, which occur during the different physiological phases. Dynamics of the protein profile - from pregnancy to dry period - which are provided by our results, could be considered as guidelines for the management strategies to guarantee the nutritional needs of these animals during the different physiological phases and to avoid a decline of productive performance and consequently an economic loss.

Modulation of peripheral markers of the serotoninergic system in healthy horses.

To evaluate the changes in plasma and platelet serotonin (5-HT) as markers of the serotoninergic system in equines, 5-HT content was measured by high performance liquid chromatography (HPLC) in deproteinized plasma obtained from peripheral blood samples of 12 clinically healthy horses, before and after feeding. 5-HT was measured in platelet rich plasma (PRP) and in platelet poor plasma (PPP). 5-HT in platelets (p5-HT) was obtained by subtracting free 5-HT in PPP (f5-HT) from 5-HT in PRP. After food ingestion, significant increases in p5-HT and f5-HT (p < 0.001), and no changes in the f5-HT/p5-HT ratio were recorded. Increase in the total circulating 5-HT might account both for initiating peristaltic activity and for increasing the f5-HT levels. Augmented 5-HT uptake by platelets could reflect the hypothetical increased activity of the serotoninergic neurons. Besides showing the feasibility to obtain f5-HT and p5-HT through HPLC determination of 5-HT in PRP and PPP equine plasma, these findings are consistent with the postulation that 5-HT is released from enterochromaffin cells following a mechanical and chemical stimulation.

Estrogenic followed by anti-estrogenic effects of PCBs exposure in juvenil fish (Spaurus aurata).

Vitellogenin (Vtg) is a phospho-lipo-glycoprotein produced by oviparous animals in response to estrogen receptor (ER) binding. The presence of Vtg in juvenile and male fish liver and plasma has been used as biomarker to evaluate levels of environmental contaminants as dioxin and PCBs. Interaction of dioxins and PCBs with aryl hydrocarbon receptor (AhR) may affect reproduction by recruitment of estrogen receptor alpha (ERalpha). The aim of this study was to investigate the effects of PCB-126, a co-planar PCB prototypical AhR agonist, and of PCB-153, a non-coplanar PCB lacking dioxine-like activity, on Vtg expression in young fish (Spaurus aurata) after a 12 or 24h exposure to PCBs as well as 48h following PCBs removal. Vtg expression was evaluated by immunohistochemistry and by Western-blot analysis. Our results showed an increased Vtg expression following PCBs administration, with a maximum level after 12h of exposure to either PCB-126, PCB-153 or a mixture of both PCBs. Following this estrogenic activity, an anti-estrogenic activity was detected after 24h of incubation with PCB-126 (alone or mixed with PCB-153), suggested by a decrease in Vtg expression likely through AhR, as a consequence of a hypothetic defence mechanism to endogenous or exogenous ligands.

Analysis of serum proteins in clinically healthy goats (Capra hircus) using agarose gel electrophoresis.

BACKGROUND: Electrophoretic patterns of serum proteins provide useful information on pathological conditions in ruminants. Their reference values, however, are dissimilar to those of other species. Reference values for goats using agarose gel as the supporting matrix have not been reported. OBJECTIVE: The aim of this study was to evaluate serum concentrations of total protein and protein fractions (albumin and globulins) by means of agarose gel electrophoresis (AGE) in goats in order to establish electrophoretic reference intervals and to evaluate potential changes associated with aging. METHODS: Blood was collected from 105 clinically healthy Girgentana goats by means of jugular venipuncture. Serum protein concentrations were assessed by AGE. Three age groups were compared: 1-1.5 years, 2-4 years, and 5-12 years. RESULTS: Values (mean ± SD) were determined for concentrations of total protein (72.26 ± 6.40 g/L), albumin (31.80 ± 4.00 g/L), α-globulins (6.40 ± 1.23 g/L), ß(1) -globulins (10.50 ± 2.58 g/L), ß(2) -globulins (5.18 ± 1.60 g/L), and γ-globulins (18.65 ± 5.90 g/L) and for albumin/globulin (A/G) ratio (0.82 ± 0.20). One-way ANOVA showed statistically significant age-related differences for total protein and α-globulin concentrations and A/G ratios. Age influenced protein concentrations with the 5-12-year-old group having higher total protein and α-globulin concentrations and lower albumin concentration and A/G ratios than the 2-4-year-old group. CONCLUSIONS: This study provides reference values for total protein concentrations and protein fractions obtained by AGE in goats. Some values vary with age. Age-specific reference intervals are reported in order to provide clinicians with an additional diagnostic aid.

Effect of diet on plasma tryptophan and serotonin in trained mares and geldings.

Concentrations of tryptophan (TRP) and serotonin (5-HT) in plasma were measured in 36 moderately trained Dutch warmblood horses after eight weeks on a high fibre (n=18) or high starch (n=18) diet. Samples were taken three hours after feeding, when the horse was at rest, either at 11.00 or 14.00 hours. Plasma 5-HT and pH were significantly higher in horses fed a high fibre diet than those fed a high starch diet (P<0.05 and P<0.01, respectively), and significantly higher levels of TRP were found in mares than geldings (P<0.05). Plasma 5-HT may therefore be a good marker of serotonergic activity.

Effect of long-distance road transport on thyroid and adrenal function and haematocrit values in Limousin cattle: influence of body weight decrease.

The purpose of this study was to evaluate the effect of long-distance road transport as a relevant stressor on total and free iodothyronines, cortisol levels and haematocrit values in 10 male Limousin cattle. Serum T3,T4,fT3,fT4 and cortisol concentrations were analysed by immunoenzymatic assays. Serum cortisol levels and haematocrit modifications were also evaluated on the basis of percentage body weight decrease. The results showed a general increase of total and free iodothyronines and cortisol levels after short-and long-distance road transport and a decrease 15 days after transport, as compared to basal values. Significant positive correlations between T3 and T4, between T3 and fT3, and between T4 and fT4 were found. These results suggest that transport stress induces an increase in the activity of thyroid and adrenal function in Limousin cattle that is evident after even a short-distance road transport and continues to increase after long-distance transport.

A lactate-guided conditioning programme to improve endurance performance.

Blood lactate measurements are used widely in horses to assess athletic performance, but there are few published data on using lactate as a guide for endurance improvement. The velocity at which blood lactate concentration ([LA]) of 4 mmol/l is reached (v4) is widely used to determine fitness. In an earlier study of v4, exercise at low intensities for longer duration was more effective at improving endurance than shorter, higher intensities. However, the prescription was unchanged during the study (6 weeks). We hypothesised that, to produce greater improvement in v4 in the same time frame, it is necessary to adjust conditioning regimes more frequently. Six horses underwent an initial treadmill-based standard exercise test (SET). A regression analysis [LA]-speed relationship was used to calculate v2. Horses were then conditioned for 45 min at their calculated v2 3 times/week (6% incline). Every 2 weeks the horses performed an SET to evaluate the v2 conditioning protocol which ended with SET 4. Mean v4 increased 17% from SET 1 to SET 4 (P = 0.003; 5.8 +/- 03 to 6.8 +/- 0.4 m/s). This study demonstrates that a lactate-guided conditioning programme can significantly enhance endurance performance over a 6-week time peroid when the conditioning protocol is adjusted every 2 weeks based on v4 improvement.