Plasma serotonin levels in Italian Fresian dairy cows

Abstract

The aim of this work was to investigate the metabolism of plasma serotonin or 5-hydroxytryptamine (5-HT), an important neurotransmitter, in Fresian dairy cows, a breed of zootechnical interest, using high-performance liquid chromatography with electrochemical detection. The subjects under study were at the stage of early lactation (n=10; mean body weight 375 AE 50 kg; average age of 3 years; body condition score 2.5), bred in a farm at an altitude of 150 m a.s.l. To evaluate animal welfare on this farm, which is closely connected to an animal's physiological status, tryptophan and cortisol levels (measured by enzyme-linked immunosorbent assay), together with levels of certain blood components [total proteins (TP), albumin, creatinine, glucose (Glu), triglycerides, phospholipids, total cholesterol, and aspartate transaminase, measured by spectrophotometry] were analyzed. The results obtained are discussed in comparison with reference values, taking into account the environmental living conditions. Measured plasma serotonin concentrations, which were lower than values reported for Brown Swiss dairy cows of a comparable age and diet, appeared to be affected by breed, temperature, blood sampling season, and altitude. Additional differences between the levels of plasma tryptophan, the amino acid precursor of serotonin, of the two breeds were comparable. Negative correlations between plasma tryptophan and plasma cortisol levels (r=−0.83, P<0.005), plasma serotonin and plasma TP levels (r=−0.72, P<0.05), or Glu levels (r=−0.77, P< 0.05) highlight the existence of a stress condition, which is connected to an energetic deficit related to lactation.

Phospholipid composition of plasma and erythrocyte membranes in animal species by 31P NMR

“…Indeed, even if an increase of phospholipid-bound choline during pregnancy may be required for an adequate maternal supply of choline to the fetus, it was reported that cows fed rumen-protected choline (RPC) supplementation showed lower plasma phospholipid (PC) at the delivery than control cows (Guretzky et al 2006). The total mean PL levels for cow plasma found, 2.20±0.67 mmol/L, are consistent with ones previously measured via spectrophotometry (Bruschetta et al 2010), thus supporting that PL recovery was total. In addition, these results confirmed that 31 P NMR spectroscopy using detergents, compared to conventional analytical approaches, is a relatively fast and accurate method for the quantitative analysis of PL extracts from biological samples.…”

A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators

“…The 5‐HT EC 50 values estimated here for EDA (~45 ng/ml) were about three times lower than those recorded for BDA (~127 ng/ml). Although caution must be taken when data from in vivo and in vitro findings are related, the greater 5‐HT potency recorded in equine may be consistent with the lower free plasma levels of 5‐HT measured (by HPLC) in healthy horses (~3.5 ng/ml) than in cows (~170 ng/ml) (Bailey & Elliott, ; Bruschetta, Di Pietro, Sanzarello, Giacoppo, & Ferlazzo, ; Menzies‐Gow, Bailey, Katz, Marr, & Elliott, ).…”

An Appraisal of Methods for Measuring Welfare of Grazing Ruminants

“…However, as shown in the extensive review of their relation to various pathological states in horses (54), the picture in relation to stress is confusing. Nevertheless, a study of plasma serotonin levels in dairy cows showed the values to be elevated by the stress of negative energy balance (55). This seems to be a measure with potential for detecting the existence of stress conditions in farm animals although the involvement of platelets in metabolism of serotonin means that measurement of free serotonin concentrations is best done with platelet-poor plasma.…”