Effect of age on androgens pattern in cyclic mares

Androgens are produced in both sexes. In females produced by the adrenal gland and the ovaries they play a crucial role in regulating ovarian function, estrogen synthesis and follicular growth. Age leads to a reduction in androgen concentrations, although, at present, these mechanisms are not elucidated in mares. The objective of this study was to evaluate the concentrations of testosterone (T), androstenedione (A4) and dehydroepiandrosterone (DHEA) in mares of different ages. Blood samples were drawn from seventy cyclic Spanish Purebred mares belonging to five age groups: 3-5 years, 6-9 years, 10-13 years, 14-16 years and > 16 years. The concentrations of T, A4 and DHEA were determined by EIA, validated specifically for horses. Mares aged 3-5, 6-9 and 10-13 years had higher T concentrations (P < 0.05) than mares aged >16 years, and mares aged 6-9 years had also higher concentrations than those 14-16 years old (P < 0.05). A4 concentrations were lower (P < 0.05) in mares >16 years old when compared with those of other age groups. DHEA concentrations were lower (P < 0.05) in mares 14-16 years and > 16 years old when compared with those of other age groups. DHEA was positively correlated with T (r = 0.61; P < 0.05) and A4 (r = 0.51; P < 0.05). Age induces reduction in androgens' synthesis in physiologically cyclic Spanish Purebred mares. These physiological variations must be duly considered for a correct and objective interpretation of the analytical data.

Correlation between erythrocyte parameters and iron status in cyclic Spanish Purebred mares

The aim of this study was to evaluate the serum iron status and its relation to hematological indexes in cyclic mares. Blood samples were taken from 40 Spanish Purebred mares on days - 5, 0, + 5 and + 16 of their cycle. Concentration of transferrin (TRF) was significantly lower on day 0 than on days + 5 and + 16, transferrin saturation (TSAT) decreased significantly on days 0 and + 16 compared to day - 5, total iron-binding capacity (TIBC) on day + 16 was significantly higher than those on days - 5 and 0, and on day + 5 it was also significantly higher than that on day 0, unsaturated iron-binding capacity (UIBC) was reduced on day + 16 compared to days - 5 and 0, red blood cell (RBC) count on day + 16 was higher than that on days - 5 and 0 (p < 0.05), with no differences in the concentration of hemoglobin (HB) and packed cell volume (PCV). TRF and TIBC (r = 0.95), RBC and HB (r = 0.64), RBC and PCV (r = 0.78), and HB and PCV (r = 0.63) were positively and significantly correlated (P < 0.05). The estrous cycle in the Spanish Purebred mare is characterized by an increase in TRF and TIBC during the follicular phase and an increase in TSAT, UIBC and RBC in the luteal phase, without changes in other hematological parameters. The coordinated activity of these parameters guarantees an adequate iron (Fe) transfer and utilization during follicular development, ovulation, and the luteal period in the mare. Therefore, the estrous cycle must be considered in the evaluation of the mare's iron status, in light of significant changes observed both in early and at late luteal phases. The magnitude of these changes and the meaning to the physiology of the mares showed that in cyclic mares, hematological parameters and indicators of iron status evolve differently depending on the phase of the cycle, and their interpretation can help to veterinarians involved in equine practice.

Estrogen-iron axis in cyclic mares: Effect of age

In woman and in animal models, estrogens are involved in iron (Fe) homeostasis supporting the hypothesis of the existence of an "estrogen-iron axis". Since advancing age leads to a decrease in estrogen levels, the mechanisms of Fe regulation could be compromised. In cyclic and pregnant mares, to date, there is evidence linking the iron state with estrogens pattern. Then, the objective of this study was to determine the relationship among Fe, ferritin (Ferr), hepcidin (Hepc) and estradiol-17β (E2) in cyclic mares with advancing age. A total of 40 Spanish Purebred mares of different ranges of age was analyzed: 4-6 years (n = 10), 7-9 years (n = 10), 10-12 years (n = 10), and >12 years (n = 10). Blood samples were obtained on days -5, 0, +5 and + 16 of the cycle. Compared to mares of 4-6 years, serum Ferr was significantly higher (P < 0.01) and Fe significantly lower (P < 0.01) in mares >12 years of age. Hepc was significantly higher in mares >12 years (P < 0.01) than in those 7-9 years of age. E2 levels were higher in mares of 7-9 years (P < 0.01) than in 4-6 and >12 years of age. Fe and Ferr were negatively correlated with Hepc (r = -0.71 and r = -0.02, respectively). E2 was negatively correlated with Ferr and Hepc (r = -0.28 and r = -0.50, respectively), and positively with Fe (r = 0.31). There is a direct relationship between E2 and Fe metabolism, mediated by the inhibition of Hepc in Spanish Purebred mares. The reduction of E2 decreases the inhibitory effects on Hepc, increasing the levels of stored Fe and mobilizing less the free Fe in circulation. Based on the fact that ovarian estrogens participate in changes in the parameters indicative of iron status with age, the existence of an "estrogen-iron axis" in the mares'estrous cycle could be considered. Future studies are required to clarify these hormonal and metabolic interrelationships in the mare.

Hematological indexes and iron status in pregnant mares

During pregnancy, iron requirements are increased to meet optimal placental and fetal growth and the expansion of the maternal red-cell mass and to prevent complications related to the mother's iron deficiency anemia. Red-cell parameters and iron status provide consistent additional information for diagnosis of iron deficiency conditions. The aim of this study was to evaluate the serum iron status and its relation to hematological indexes in pregnant mares. Blood samples were taken from 31 Spanish Purebred mares over 11 months of pregnancy. Concentrations of iron (Fe), ferritin (Ferr), transferrin (T), and total iron-binding capacity (TIBC) increased significantly and unsaturated iron-binding capacity (UIBC) decreased as the pregnancy progressed without changes in red blood cell (RBC) count, hemoglobin (HB) concentration, packed cell volume (PCV), and transferrin saturation (TSAT). Fe and Ferr were positively correlated (r = 0.21 ). Fe and T (r = 0.69 ) and Fe and TSAT (r = 0.94 ) were positively correlated, and Fe and UIBC were negatively correlated (r = - 0.69 ). T and TIBC were positively correlated (r = 1.00 ). Pregnancy in the Spanish Purebred mare is characterized by a progressive increase in Fe, Ferr, T, and TIBC and a decrease in UIBC without modification in hematological indexes. Hematological parameters and iron status seem to indicate a sufficiency for Fe transport and its related mobilization and utilization during gestation in Spanish Purebred mares.

Contribution of Hemogram Plan in the Horse's Clinical Evaluation

The interpretation of the blood count is essential to help the equine clinician in the diagnosis, prognosis, patient management, and control of equine diseases. Hematologic alterations often reflect the condition of the individual or an overall response to a pathological situation. A thorough clinical examination of the patient is essential to correctly interpret the hematological results. The most common abnormalities in the erythrogram are mainly anemia and polycythemia. The frequent causes of anemia in horses are acute and chronic blood loss, hemolytic anemia, and anemia caused by chronic disease. Evaluation of leukogram, including a total white cell count, a differential cell count, absolute numbers of specific leukocytes can help identify abnormalities that may suggest specific diseases such as a viral or bacterial infection, inflammatory disorders or even a neoplastic process. The platelet count is most often used to monitor or diagnose conditions that cause too much bleeding related with thrombocytopenia; it can be due to multiple mechanisms such as reduction of thrombopoiesis (myeloptisis, myelofibrosis, myeloproliferative disease, and idiopathic medullary aplasias or due to the effect of mielosuppresive drugs), increased peripheral destruction of platelets (immune mediated thrombocytopenia), consumption (dissemined intravascular coagulation) sequestration of the spleen and loss of platelets by idiopathic origin.

Biochemical and Hematological Indexes of Liver Dysfunction in Horses

In the present review, the authors, based on the multiple functions performed by the liver, analyze the multiple biochemical and hematological changes as an expression of altered liver function in the horse. The liver performs important metabolic functions related to the synthesis, degradation, and excretion of various substances. Modification of these functions can be evaluated and diagnosed by determining serum concentrations of several serum analytes, including enzymes and other endogenous substances. Hepatocellular enzymes, such as sorbitol dehydrogenase-SDH and glutamate dehydrogenase-GLDH, are released following hepatocellular necrosis. Hepatobiliary enzymes, such as γ-glutamyl transferase-GGT, increase in response to necrosis, cholestasis, and other alterations in bile conducts. Serum concentrations of mainly endogenous and exogenous substances that the liver should synthesize or eliminate, such as proteins (albumin and globulins), bile acids, urea, glucose, total and direct bilirubin, and coagulation factors, and fibrinogen should be included in the liver function test profile. The interpretation of laboratory tests of liver function will allow the diagnosis of functional loss of the organ. Some of the analytes considered provide information on the prognosis of liver disease. This review will provide an accurate and objective interpretation of the common biochemical and hematological tests in use in the diagnosis of equine hepatic disease patients, aiding still further the veterinary activity on the applied equine clinical cases.

Adaptive response of estrogen-iron axis in pregnant Purebred Spanish mares of different age

The maintenance of iron (Fe) homeostasis is vital for the physiological function along life. In sexually mature humans and experimental animals, estrogens downregulate hepcidin (Hpc) expression, in order to improve the intestinal absorption and to mobilize Fe stores for maternal erythropoietic expansion and placental development. However, changes of these mechanisms related to regulation of Hpc on the availability of Fe during gestation with advancing age in mares, remain unknown. The objective of this study was to evaluate the interrelationships between serum Fe, Ferritin (Ferr) and Hpc with estrone (E₁) and estradiol-17β (E₂) concentrations in pregnant mares of different ages. Blood samples were taken from 40 pregnant Spanish Purebred mares belonging to 4 different age groups, 10 subjects for each group: 4-6 years, 7-9 years, 10-12 years, and > 12 years were used in this study. Fe concentrations of 4-6 and 7-9 years groups were higher (P < .01) than 10-12 and >12 years groups. Ferr concentrations of 4-6 years group were higher (P < .01) than other groups. Hpc concentrations increased and E₁ decreased (P < .01) in > 12 years group compared to other age groups. E₂ concentrations of 7-9, 10-12 and >12 years groups were higher (P < .01) than those of 4-6 years group; 7-9 years group had higher E₂ concentrations (P < .01) than > 12 years group. Fe and Ferr were negatively correlated with Hpc (r = -0.81 and r = -0.67, respectively). E₁ and E₂ were negatively correlated with Fe (r = -0.23 and r = -0.11, respectively). E₂ was positively correlated with Hpc (r = 0.78). In pregnant Spanish Purebred mare, the increase of estrogens, according to the more efficient iron status in response to Hpc inhibition and consequent mobilization of circulating and iron reserve, shows the existence of "estrogen-iron axis" in young mares. Nevertheless, these mechanisms are reversed in old mares, suggesting a less efficient iron metabolism with advancing age. It is hoped that new investigations are needed to understand in depth and clarify further the complex metabolic and hormonal mechanisms involved also in equine species.

Hepcidin, ferritin and iron homeostasis in pregnant Spanish Purebred mares

During pregnancy, maternal erythropoietic expansion and fetal development require greater mobilization of available iron (Fe) stores. These adjustments in Fe metabolism in humans and rodents are largely mediated by the hormone hepcidin (Hepc), which controls the expression of ferroportin (Fpn), a transporter responsible for exporting Fe from stores to extracellular fluid and plasma. These mechanisms based on the regulation of Hepc on the availability of Fe during gestation in healthy mares remain unknown. The objective of this study was to determine the existence of interrelationships among concentrations of Hepc, ferritin (Ferr), Fe, and estrone (E₁) and progesterone (P₄) in Spanish Purebred mares along the whole gestation. Blood samples were taken from 31 Spanish Purebred mares each month, during 11 months of pregnancy. Fe and Ferr significantly increased and Hepc decreased during pregnancy (P < 0.05). The secretion peak of estrone (E₁) was reached in the 5th month and progesterone (P₄) between the 2nd and 3rd months of gestation (P < 0.05). Fe and Ferr were weakly positively correlated (r = 0.57; P < 0.05). Fe and Ferr were negatively correlated with Hepc (r = -0.80 and r = -0.67, respectively) (P < 0.05). P₄ was positively correlated with Hepc (r = 0.53; P < 0.05). Pregnancy in the Spanish Purebred mare was characterized by a progressive increase in Fe and Ferr and a reduction in Hepc concentrations. E₁ was partially responsible for the suppression of Hepc; on the other hand, P₄ induced its stimulation during pregnancy in the mare.

Changes of Hepcidin, Ferritin and Iron Levels in Cycling Purebred Spanish Mares

Several studies have demonstrated that in woman the sex hormones such as estrogen (E2) and progesterone (P4) influence iron (Fe) regulation, contributing to variations in Fe parameters along the menstrual cycle. These mechanisms based on the regulation of hepcidin (Hepc) which limits Fe availability during the cycle, remain poorly characterized in healthy mares. The objective of this study was to establish the relationship between Hepc, Fe, ferritin (Ferr), and the primary ovarian hormones E2 and P4 in cycling Purebred Spanish mares. Blood samples were taken from 31 Purebred Spanish mares day −5, on day 0, day +5 and day +16 of the cycle. Fe and Ferr significantly increased and Hepc decreased during pre- and ovulatory periods. The secretion peak of estradiol-17β (E2) was reached on day 0 and progesterone (P4) between days +5 and +16. Fe and Ferr were positively correlated (r = 0.57). Fe and Ferr were negatively correlated with Hepc (r = −0.72 and r = −0.02, respectively). E2 and P4 were negatively and positively correlated with Hepc (r = −0.753 and r = 0.54, respectively). In cycling Purebred Spanish mares there is a measurable relationship between steroid hormones and systemic Fe metabolism. Estrogenic dominance in the pre- and ovulatory period allows for a more effective iron status, mediated by hepcidin inhibition. However, P4 during the luteal phase substantially reduces serum Fe and iron stores, possibly related to Hepc stimulation. Future research is required to clarify the relationship between steroid hormones and iron metabolism at the molecular level in equids.

Thyroid evaluation in suspicious hypothyroid adult dogs before and after treatment

The purpose of this study was to measure circulating TSH, T4 and fT4 concentrations in dogs submitted to a clinical visit for general symptoms (weight gain, polyuria and polydipsia, changes in hair coat). Twenty-eight dogs, 14 cross-breed and 14 purebreds (Golden Retriever, Labrador, Doberman), of both sexes (14 males and 14 females), aged 8 to 14 years, were assessed. No significant differences of circulating TSH, T4 , fT4 concentrations between the baseline and after therapeutic treatment nor between intact and neutered females were observed. Compared to baseline values, intact males showed higher TSH concentrations (p⟨0.01), and castrated males lower TSH concentrations (p⟨0.01) after therapeutic treatment. Compared to intact males, castrated males showed baseline TSH concentrations higher (p⟨0.01), but lower (p⟨0.01) after therapeutic treatment. No significant differences of T4 and fT4 concentrations between baseline conditions and after therapeutic treatment, nor between intact and castrated males, were observed. The experimental sample considered in this study falls within that casuistry involving elevated TSH concentrations but low serum T4 and fT4 concentrations or close to the minimum physiological cut-off, in which the common clinical signs suggestive of hypothyroidism was, essentially, overweight and neglected appearance of the hair.

Assessment of selected molecular factors and 17-β estradiol dosage in response to Toxoplasma gondii infection in swine

Background and Aim:

Toxoplasma gondii is a global zoonotic parasite infecting virtually all warm-blooded species, although a species-specific variability is evident referring to symptoms frame. Both the success of T. gondii and the outcome of infection depend on a delicate balance between host cellular pathways and the evasion or modulation strategies elicited by the parasite. The hormonal and molecular mechanisms involved in this delicate host-parasite balance are still unclear, especially when considering intermediate host species other than mouse. This study aimed to assess any correlation between T. gondii infection and selected molecular and hormonal factors involved in responses to infection in susceptible species such as swine. Moreover, blood counts and hematochemical assays (glucose, total cholesterol, and triglycerides dosage) were performed to evaluate the overall health condition of animals.

Materials and Methods:

Toxoplasmosis was diagnosed by enzyme-linked immunosorbent assay for antibodies determination and real-time polymerase chain reaction (RT-PCR) for T. gondii DNA detection. Target genes coding for key factors of cell responses to T. gondii infection were selected, and their transcription was assessed in various tissues by quantitative RT-PCR. 17-β estradiol concentrations were assessed by fluorimetric enzyme-linked immunoassay and the AIA-360 automated immunoassay analyzer. Blood count and hematochemical analyses were performed by a blood cell counter and a spectrophotometer, respectively.

Results:

The present research highlighted significant differences among infected and uninfected swine (control group) for both transcription profiles of some of the molecular factors considered and 17-β estradiol concentrations. Referring to the assessed hematological and biochemical parameters, no statistically significant differences were observed in infected swine compared to the control group.

Conclusion:

Our results contribute to the enrichment of data available about the subject and could be useful for a deeper knowledge of the interaction between this parasite and its hosts. However, more aspects are still unclear, such as the effective response of downstream molecules from the same pathways to the variation of factors observed in this study either assessing how the same factors respond to Toxoplasma gondii infection in other host speciesand further analyses should be performed on other host species.

Successful Pregnancy Outcome in Mares: The Potential Role of Body Conditional Score, Age and Biochemical Parameter's Adjustments

The objective of this research was to evaluate the changes in body condition score (BCS), age and the main biochemical parameters in pregnant Spanish Purebred mares. A total of 45 pregnant Spanish broodmares has been studied, classified in three different groups: group A (n = 15), aging 14-18 years old and BCS lower than 4 of 10, group B (n = 15), with ages of 4 to 8 years and a BCS of 5-6/10, and group C (n = 15), aging between 6 and 11 years and a BCS of 8 of 10. Three pregnancy periods were considered: the 1st period, from the 1st to the 3rd, the 2nd from the 4th to the 6th, and the last period, from the 7th month of pregnancy to delivery. Blood samples were taken every month along the pregnancy. The following plasma biochemical parameters were measured: triglycerides, total cholesterol, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, total, direct and indirect bilirubin, aspartate aminotransferase, lactate dehydrogenase, γ-glutamyl transferase, alkaline phosphatase, total plasma proteins, albumin, glucose, urea and creatinine. Pregnancy in the Spanish broodmare induced hyperlipidemia with hypertriglyceridemia and increased plasma concentrations of total, direct and indirect bilirubin (P < .05). Older pregnant mares showed biochemical changes probably consistent with decreased organ functionality (P < .05). Obesity did not influence lipidic metabolism during pregnancy (P > .05).

Effects of standardized exercise tests on plasma thyroid hormones' kinetics in Standardbred racehorses

This study examined how a standard exercise test (SET) affected (1) thyroid hormones (THs) of horses and (2) the relationship between the V_La4 of horses and TH responses to the exercise in trained Standardbred racehorses (V_La4 is the velocity run at defined conditions at which a blood lactate concentration of 4 mmol/L is determined). 12 trained Standardbred racehorses (six stallions and six mares) performed SETs until the horses' blood lactate concentration was at or above 4 mmol/L. The horses were divided into three age groups (2, 3 and 4 years old); each group consists of 4 horses respectively (2 male and 2 female), to evaluate the effects of age and sex on hormonal responses to SET. During each SET, blood samples were taken at rest and after each interval and at the end of SET. Blood was analysed for total and free triiodothyronine (T3, fT3) as well as total and free thyroxine (T4, fT4). The statistical model included three fixed factors (SET, sex and age) and their main interactions. ANOVA analysis revealed that T3 and fT3 were significantly influenced by SETs. Plasma T3 and fT3 concentrations were higher in 4-year-old horses compared to the other age groups. All plasma THs concentrations were higher in mares than in stallions. Correlations revealed that a higher V_La4 was negatively related to all THs responses in 2-year-old Standardbred mares only. The SET used to determine V_La4 increased selected THs (T3, fT3); these increases were inversely related to V_La4 and affected by age and sex of the horses. The correlation of V_La4 with thyroid exercise' response might provide some additional information for performance evaluation of Standardbred racehorses, especially for evaluating training adaptation, according to sex and age. Further studies are necessary to provide support on the value of measuring THs in Standardbred racehorses of different sex and age.

Interrelationship between reproductive hormones and acute phase proteins during estrous cycle and pregnancy in Spanish purebred broodmares

In some species, female steroid hormones modify the profile of acute phase proteins (APPs) during the estrous cycle and pregnancy, according to the ovulation, embryonic implantation and placental development; however, nowadays there's no experimental evidence for equine species. Objectives of this study were: to compare the serum amyloid A (SAA), haptoglobin (Hp) and C-reactive protein (CRP) concentrations between cyclic and pregnant mares, and to analyze the influence of estradiol-17β (E2) during estrous cycle or estrone sulfate (E1) during pregnancy, and progesterone (P4) on these proteins to assess their potential role to identify the cyclicity or pregnancy in Spanish mares. Blood samples were taken from 20 Purebred Spanish mares on the day of ovulation (day 0), on days +5 and +16 post-ovulation, and then, monthly during the whole pregnancy. SAA, Hp and CRP did not change between day 0, +5 and +16 post-ovulation days. P4 concentrations were significantly higher on day +16 than on days +5 and 0; and E2 concentrations were significantly higher on day 0 than day +5. On the other hand, pregnancy was characterized by a progressive increase in the Hp, variable modifications of E1 and P4 concentrations, without changes in SAA and CRP. The absence of significant differences in the APPs between days 0, +5 and +16, suggested that these proteins cannot be used as biomarkers of diagnosis of heat or pregnancy in Spanish mares, at least early, since the Hp later increases during the gestation. Nevertheless, it is possible to use them for comparative purposes with other equine breeds, as supervisor instrument of health status in breeding females as diagnostic tools to monitor pregnancy's development and/or subclinical reproductive inflammations, that could lead to the early embryonic death.

Endocrine and Electrolyte Balances during Periovulatory Period in Cycling Mares

Simple Summary

This study provides new evidence on the physiological mechanisms involved in the electrolyte balance during periovulatory period in cycling mares. The interrelationships among adrenocorticotropic hormone (ACTH), cortisol (CORT), aldosterone (ALD) and electrolytes (sodium—Na⁺, potassium—K⁺ and chloride—Cl⁻) were evaluated. The simultaneous increase in ACTH, CORT and ALD toward the time of ovulation could suggest the involvement of the adrenocortical pituitary axis in the ovulatory mechanisms, contributing at the same time to the maintenance of electrolyte homeostasis.

Abstract

In cycling females, the periovulatory period is characterized by stimulation of the hypothalamic pituitary adrenal (HPA) axis. The aim of present study was to analyze the pattern and interrelationships among adrenocorticotropic hormone (ACTH), cortisol (CORT), aldosterone (ALD) and electrolytes (sodium—Na⁺, potassium—K⁺ and chloride—Cl⁻) during periovulatory period in cycling mares. Venous blood samples were obtained daily from a total of 23 Purebred Spanish broodmares, aged 7.09 ± 2.5 years, from day −5 to day +5 of estrous cycle, considering day 0, the day of ovulation. Plasma ACTH was measured by a fluorescent immunoassay kit, serum CORT and ALD by means of a competitive ELISA immunoassay, and plasma Na⁺, K⁺ and Cl⁻ were quantified by an analyzer with selective electrodes for the three ions. ACTH showed higher concentrations at day 0 compared to days −5 to −1 and +1 to +3 (p < 0.05). CORT showed higher concentrations at day 0 compared to days −5 to −2 and +1 to +5 (p < 0.05). ALD showed higher concentrations at day 0 compared to days −5 to −2 (p < 0.05) and +2 (p < 0.05). Na⁺ and Cl⁻ showed higher concentrations at day 0, compared to day −5 and +5. K⁺ showed lower concentrations at day 0 compared to day +1 (p < 0.05). The significant correlations obtained between ACTH and CORT (r = 0.20) and between ACTH and ALD (r = 0.32) suggest that although ACTH may have an effect both on CORT and ALD, there are other very important determinants that could be considered. Hence, it is possible to presume that the pituitary adrenocortical response and ALD may be involved in the ovulatory mechanisms without a direct relation with electrolyte pattern.

Intrafollicular and Systemic Dopamine, Noradrenaline and Adrenaline Concentrations in Cycling Mares

Simple Summary

This study provides new evidence on the physiological changes of catecholamines in follicular fluid during the follicular growth in the mare. Both dopamine and epinephrine increase in the follicular fluid with the advance of follicular development, although norepinephrine decreases. These changes could be related to the existence of systemic, autocrine and/or paracrine mechanisms of synthesis, metabolism and interconversion of catecholamines for the regulation of follicular growth and development.

Abstract

In some species, catecholamines in follicular fluid (FF) are related to local physiological events responsible for the regulation of ovarian functions and oocyte maturation. The aim of the present study was to determine and compare intrafollicular and systemic concentrations of dopamine (DA), noradrenaline (NA) and adrenaline (AD) in cycling mares. Sixty ovaries were collected during breeding season from 30 mares raised for slaughterhouse meat production, with clinically normal reproductive tracts, were evaluated. Blood samples were collected prior to slaughter. Follicles were classified into three categories in relation to size: small (20–30 mm; n = 20), medium (≥31–40 mm; n = 20) and large (≥41 mm; n = 20). Follicular fluid (FF) samples were extracted from each follicle. Intrafollicular DA, NA and AD concentrations were significantly higher than the systemic concentrations (p < 0.05). Intrafollicular DA concentrations were higher in medium than small and large follicles (p < 0.05). Intrafollicular NA concentrations were higher in small than medium and large follicles (p < 0.05). Intrafollicular AD concentrations were higher in large than small and medium follicles (p < 0.05). Follicle diameter was significantly and negatively correlated with NA and AD (p < 0.05). A significant correlation of the same hormone concentration in FF and in systemic fluid was observed (p < 0.05). In summary, the FF can serve as an intraovarian catecholamine-storing compartment, with the ability to release neurotransmitters in a regulated way. These results provide novel insights into the neuronal nature of the follicle, suggesting the involvement of catecholamines in normal ovarian functions in mares.

Functional response of systemic and intrafollicular placental growth factor in cycling mares

The aim of the study was to assess the physiological reference values for systemic and intrafollicular placental growth factor (PlGF) concentrations in different categories of follicular sizes in cycling mares, according to progesterone (P4) and oestradiol (E2) patterns. Sixty ovaries were taken after slaughter from 30 clinically healthy mares. Regarding their size, the follicles were classified into three different categories, i.e. small (20-30 mm), medium-sized (31-40 mm) and large (≥41 mm), and follicular fluid (FF) was sampled from each single follicle. Intrafollicular PlGF concentrations were significantly increased in larger and medium-sized follicles compared to small follicles, and their values were 1.48 and 1.36 times higher than the systemic values, respectively. On the other hand, systemic PlGF concentrations were 1.3 times higher than those in the FF of follicles of small size. Intrafollicular P4 concentrations were significantly higher in larger follicles than in small ones, and their concentrations were 6.74 and 3.42 times higher than the systemic values, respectively. Intrafollicular E2 concentrations were significantly higher in large and medium-sized follicles than in follicles of small size, and their concentrations were 21.1, 15.4 and 8.35 times higher than the systemic values, respectively. Intrafollicular and systemic PlGF concentrations were strongly and positively correlated; nevertheless, no correlations between intrafollicular and systemic steroid hormones, PlGF and follicle diameters, PlGF and E2, or PlGF and P4 were observed. This represents the first study to characterise systemic and intrafollicular PlGF concentrations in cycling normal mares, providing evidence that the bioavailability of this factor in follicles of medium and large sizes was higher than in small follicles, independently of steroid hormone concentrations. Further studies are needed to assess the presumable implications of PlGF in follicular angiogenesis in mares, similar to those already observed in women and primates.

Age- and Sex-Related Modifications of Hematology in Spanish Purebred Horse

The purpose of this study was to test the hypothesis that age and sex significantly modulate the changes in hematological parameters of physiologically healthy Spanish Purebred horse, establishing the reference values. Blood samples were obtained on a total of 159 horses (n = 77 males and n = 82 females), classified in four age groups: group A (1-2 years; n = 39), group B (>2-3 years; n = 38), group C (>3-4 years; n = 41), and group D (>4-7 years; n = 41). By means ADVIA 2020i, red blood cell (RBC), hemoglobin concentration (HB), packed cell volume, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration, platelets (PLTs), as well as total and differential white blood cells (WBCs) were determined. Total plasma protein was determined by spectrophotometry. Results obtained showed that sex had a limited influence on these parameters, being the HB higher in males and WBC higher in females (P = .047). Age caused a reduction in RBC, with a compensatory increase of MCV and MCH, decrease in WBC, PLT, lymphocytes (LYMPs), as well as an increase of N/L ratio (P = .047). Interactions between age and sex showed higher RBC in males than in females of the group B, and higher HB and WBC in males than in females of the group D. According to hematological data, Spanish Purebred horse was classified as a warm- or cold-blooded horse. Decline of RBC, WBC, and PLT parameters is a natural condition of horse with the advance of age, indicating a decrease of the narrow bone response.

Endometrial Cytology During the Different Phases of the Estrous Cycle in Jennies: New Evidences

Since in the mare and other animal species such as bitches and cats, the endometrial cell pattern varies depending on the phase of the estrous cycle, the aim of this study was to describe and quantify the endometrial cytological (EC) findings in cycling jennies. EC of eight nonpregnant jennies by cytobrush (CB) at diestrus (day 1 and day 14) and estrous (day 21) were evaluated. All slides were stained with Wright´s stain and microscopically examined at both 400× and 1000× magnification. Seven high-power fields (400×) were assessed in each smear and the endometrial epithelial cells and neutrophils (PMNs) were counted. Endometrial epithelial cells were classified as intact, distorted or fragmented and, on the basis of the presence of dense groups, in monolayer or single clusters. Cytoplasmic characteristics, such as vacuolation or streaming and size, form, position of nuclear characteristics, including karyorrhexis, were recorded. Background aspect, as clear, proteinaceous, or debris, was also considered. In general, sampling by CB provided a yield of cells and clumped endometrial epithelial cells in many smears, being more abundant in estrus than early and late diestrus. Individual endometrial epithelial cells, during estrous, presented a columnar morphology, ciliated or not ciliated and basal nuclei. During diestrus phase, endometrial epithelial cells presented a more cuboidal ciliated or not ciliated morphology. Moderate amount of proteinacious material and red blood cells (RBC) was also observed. Non variation in the percentage of PMNs during diestrus was obtained, but lower and segmented PMNs in CB smears were shown in estrous. This study provides new insights on the physiological changes of endometrial epithelial cells in cycling jennies during the estrus cycle. The CB technique represents a suitable and adequate method for endometrial evaluation, taking into account cytological and/or cytopathological purposes also in jennies.

The different hormonal system during exercise stress coping in horses

The review discusses the hormonal changes during exercise stress. The exercise generally produces a rise of adrenaline (A), noradrenaline (NA), adrenocorticotropic hormone (ACTH), cortisol, glucagon, growth hormone, arginine vasopressine, etc., and a drop of insulin. The hormonal events during reestablishment of homeostasis due to exercise stress can be divided into a catabolic phase, with decreased tolerance of effort, and reversible biochemical, hormonal and immunological changes, and an anabolic phase, with a higher adaptive capacity, and enhanced performance. The two main hormonal axes activated in the catabolic phase are sympathetic–adrenal–medullary system and hypothalamic-pituitary-adrenal (HPA) axis, while in the anabolic phase, growth hormone-insulin-like factor I axis, and gonadal axes. The hormonal responses during exercise and recovery can be regarded as regulatory and integrated endocrine responses. The increase of catecholamines and ACTH is dependent on the intensity of exercise; a marked increase in plasma A occurs during exercises with high emotional content. The response of cortisol is correlated with the duration of exercise, while the effect of exercise duration on b-endorphin changes is highly dependent on the type of exercise performed. Cortisol and b-endorphin changes usually occur in phase, but not during exercises with high emotional content. Glucocorticoids and iodothyronines are involved in meeting immediate energy demands, and a model of functional interactions between HPA axis and hypothalamic-pituitary-thyroid axis during exercise stress is proposed. A modulation of coping responses to different energy demanding physical activities required for sport activities could be hypothesized. This review supports the proposed regulation of hypophysiotropic TRHergic neurons as metabolic integrators during exercise stress. Many hormonal systems (ghrelin, leptin, glucose, insulin, and cortisol) are activated to control substrate mobilizations and utilization. The cardiovascular homeostasis, the fluid and electrolyte balance during exercise are highly dependent on vasoactive hormones (antidiuretic hormone, atrial natriuretic peptide, renin–angiotensin–aldosterone, and prostaglandins) control.

Age-related functional changes of total thyroid hormones and glycosaminoglycans in growing calves

Background and Aim:

During the physiological growing, thyroid and proteoglycan glycosaminoglycan (GAG) changes dynamically occur, according to genetic and non-genetic factors. The purpose of this research was to compare the effects of early postnatal development (10 days) until 210 days of life on the triiodothyronine (T₃), thyroxine (T₄), the relative T₄:T₃ ratio, and GAGs profile, and to define the different reference intervals of the calf’s development through the various growing phases.

Materials and Methods:

The effect of growing on total thyroid hormones and GAG profiles was studied from 10 days to 210days of age in 64 clinically healthy Brown calves, 30males and 34females. Blood samples were collected at 10, 20, 30, 60, 90, 120, 150, 180, and 210days of age.

Results:

The results showed a significant effect of a calf’s growth on T₃, T₄, and GAG values (p<0.0001). Significant correlations between T₃ and T₄ were observed. Compared to the previous time point, T₃ showed a significant decrease at 20days and at 60days (p<0.01), while a significant increase was observed at 90days and 210days (p<0.05); T₄ showed a significant decrease at 20days (p<0.01), while significant increases were observed at both 180days and 210days (p<0.05); GAGs showed a significant increase at 120days and 210days (p<0.05). Positive and significant correlations between BW and GAGs in both males (p<0.0057) and females (p<0.0059) were observed.

Conclusion:

It can be concluded that the highest T₃ and T₄ concentrations have been associated with the early growing process (10days), with an increasing trend also at 210days, it is possible to hypothesize a probable metabolic effect of thyroid function in anabolic and/or catabolic directions during the calves’ development. Likewise, it can be reasonably inferred that the highest plasma GAGs at 210days may be due to their metabolic role during the development of growing calves. Taken together, these findings suggest the potential and relative contribution made by thyroid and GAGs effects on the dynamics of growing calves.

Can the Presence of Ovarian Corpus Luteum Modify the Hormonal Composition of Follicular Fluid in Mares?

The hypothesis of this study was to investigate if the presence of corpus luteum (CL) in one ovary could modify the hormonal content of follicular fluid (FF) in the follicles. Sixty ovaries were taken after the slaughter of 30 clinically healthy mares. In relation to the sizes, the follicles were classified into three different categories, as small (20-30 mm), medium (31-40 mm) and large (≥41 mm). Blood samples were collected from the jugular vein of mares before their slaughter, and then the FF samplings were extracted from each single follicle. The ovaries that were collected were classified into two groups, according to the presence (CL-bearing) or absence (non-CL-bearing) of CL. The serum and FF samples were analysed for progesterone (P4), oestradiol-17β (E2), testosterone (T), androstenedione (A4) and dehydroepiandrosterone (DHEA). Intrafollicular P4 concentrations in large follicles of CL-bearing groups were lower than for non-CL-bearing ones. Intrafollicular E2 concentrations increased with the increase of the follicle diameter in both groups, CL-bearing and non-CL-bearing. However, in the FF with a large and medium follicle size, E2 concentrations were significantly higher in non-CL-bearing groups than in CL-bearing groups. T and A4 significantly increased in the large and medium follicle sizes when compared to the small follicle sizes in both groups, but higher concentrations in the non-CL-bearing group were obtained. Intrafollicular DHEA significantly decreased with the increase of the follicular diameter in both groups. Steroid hormones in FF dynamically changed, according to the presence or not of CL in the ovary. This study brings new knowledge on the role of the CL in the follicular hormonal composition in mares.

Physical Exercise Affects Serotoninergic System in Horse Leukocytes

Serotonin (5-hydroxytryptamine [5-HT]) may induce metabolic effects in different cell types, including leukocytes. In horses, 5-HT is involved in physiological and behavioral functions. Physical exercise is known to increase the amounts of 5-HT both in brain and periphery, but so far, the signal mechanism in response to exercise is not known. The aim of the study was to investigate the effect of a racehorse intensive training session on plasma 5-HT levels, serotonin transporter (SERT), 5HT_1A, 5-HT_2A, 5-HT_1B, 5-HT₇ receptor, interleukin-1 beta, and tumor necrosis factor-alpha expression in horse peripheral blood mononuclear cells (PBMC). In particular, the research was carried out on 12 trained horses performing daily training. Plasma 5-HT levels were analyzed in platelet-poor plasma fraction by enzyme-linked immunosorbent assay at T0, T1, and T2 (pretraining, 30 minutes post-training, and 2 hours post-training session), respectively. Peripheral blood mononuclear cells were isolated to perform real-time polymerase chain reaction for the evaluation of SERT, 5-HT receptor, and cytokine mRNA levels. The results showed significantly increased levels of plasma 5-HT, 5HT_1A, and 5-HT_2A and significantly decreased levels of SERT, 5-HT_1B, 5-HT₇, and both cytokine mRNAs in PBMC at T1, compared with T0 and T2. The results were confirmed by in vitro experiment. Training may induce a lower degree of 5-HT storage and, therefore, a higher plasma 5-HT concentrations. Leukocyte 5-HT receptor mRNAs seem strongly influenced by the exercise. Observed changes suggest a transient neuroendocrinological response to the exercise. A better understanding of the influence of physical exercise on serotoninergic system could have potential application for the implementation of training protocols in racing horses.

The Influence of Training and Simulated Race on Horse Plasma Serotonin Levels

Exercise represents a physical stress that challenges homeostasis affecting central and peripheral serotoninergic systems. The influence of the exercise on circulating serotonin (5-hydroxytryptamine [5-HT]) levels depends on training state as well as the exercise protocol. The purpose of the present research was to determine changes of plasma 5-HT in sport horses in response to training (T) and simulated race (SR) and in addition to assess the possible presence of significant differences on circulating 5-HT between two different sessions of exercise. In particular, the research was carried out on 18 trained horses performing daily training and race activity. Plasma 5-HT levels were analyzed in platelet poor plasma fraction by ELISA assay at T0 (before exercise), T1 (30 minutes after exercise) and T2 (2 hours after exercise). The hypothesis was that both exercise sessions could affect plasma 5-HT levels. Results showed a significant increase of plasma 5-HT levels at T1, compared with T0, both after simulated race and training activity. These effects are probably related to an increased 5-HT release from platelets and/or an increased peripheral 5-HT synthesis induced from exercise. At T2, plasma 5-HT concentrations showed a significant decrease to physiological levels in both sessions. Moreover, plasma 5-HT levels at T1 (SR) were significantly higher than those at T1 (T). Targeting peripheral 5-HT could be useful to assess the physiological adaptability of horses to the exercise, together with other selection techniques of sport horses.

Physiological Responses of Dogs to Different Housing Systems

Background: The hypothalamic-pituitary-adrenal (HPA) axis undergoes adaptations throughout housing system that might contribute to the avoidance of adverse effects of welfare status in dogs housed in a shelter. Nevertheless, the influence of housing systems and stabling time on glucose and PCV changes is little known. The purpose of the present study was to evaluate the patterns of cortisol, glucose and PCV in dogs housed in a kennel and normal environments, evaluating the differences between housing systems, by taking account the different stabling time and sex. Materials, Methods & Results:  The study comprised 98 cross-breed dogs, aged 4 ± 1.5 years, lodged in a kennel (observational group I: N= 61, 29 females and 27 males), in paired household dogs (control group II: N= 25, 13 females and 12 males) and in unpaired household dogs (control group III: N= 12, 6 females and 6 males). Females of both groups were spayed. The subjects were studied on the basis of different stabling times, ranged among <1 year, 2 years and 4 years, and different sex.Discussion: This observational study showed that kennelled males lodged for 2 (P < 0.01) and 4 (P < 0.001) years showed lower cortisol concentrations than males lodged <1 year, males lodged for <1 year (P < 0.001) showed higher cortisol concentrations than females; males lodged for 4 year showed lower cortisol concentrations (P < 0.01) than females. Kennelled females lodged for 4 year showed higher PCV values (P < 0.001) than females lodged for <1 year. Paired and unpaired household females and males lodged for 4 years showed lower cortisol concentrations (P < 0.01) than 2 years and <1 year. Paired and unpaired household females and males lodged for short-, medium- and long-term times showed higher glucose concentrations (P < 0.001) than kennelled dogs. This study showed significant changes of circulating cortisol, glucose and PCV values inter- and intra-groups, according to different housing systems, stabling time and sex. The magnitude of cortisol decreases after 2 and 4 years of stabling time in kennelled male dogs could suggest a stimulus-response relationship, probably due to adaptive responses. Interestingly enough in this observational study was that the exact consummatory event could be represented by the long stabling time itself, observed only in males. Moreover, the significant differences of cortisol concentrations between males and females in group I after a stabling time of <1 and 4 years confirm the wide variability of HPA activity independent of the different sex of dogs. The physiological higher glucose concentrations in household dogs than kennel dogs showed that the normal home environment offers probably more rich stimuli than kennel, independent of stabling times and sex. It is possible to suppose that the housing system of dogs also results in significant rise of organ reserve and adaptability, presumably due at early greatest in functional changes in the catecholaminergic system and related increased hepatic glycogenolysis and gluconeogenesis. Concerning the PCV changes, data obtained confirmed the disagreement among authors about sex differences in the circulating mass of erythrocytes according to different age and sex. In conclusion, this is an observational study on the adaptive responses of circulating cortisol, glucose and PCV patterns to different housing systems in both kennel and household, leading to the question of physiological relevance concerning the effects of different stabling, according to the quality of dogs’ life.

Intrafollicular and systemic serotonin, oestradiol and progesterone concentrations in cycling mares

The hypothesis that a local serotonergic network might also exist in the follicle of mares remains poorly documented, with exception for humans and laboratory species. For this reason, the aim of the present study was to clarify this possibility, investigating intrafollicular serotonin concentrations of the cycling mare at ovulation time. Sixty ovaries collected from 30 clinically healthy mares of slaughterhouse meat production with clinically normal reproductive tracts after slaughtering were evaluated. Blood samples were taken prior to sacrifice. Follicles were classified in three categories in relation to size, as small (20-30 mm), medium (31-40 mm) and large (>41 mm), and the follicular fluid samples were extracted from each follicle. Intrafollicular and systemic serotonin (5-HT), oestradiol-17β (E₂ ) and progesterone (P₄ ) were determined by means of enzyme-linked immunosorbent assay and RIA, respectively. Intrafollicular 5-HT, E₂ and P₄ concentrations were higher than systemic ones (p < .05). 5-HT concentrations increased in larger compared to medium follicles, without differences compared to small size follicles (p < .05). 5-HT and E₂ (r = .79) and 5-HT and P₄ (r = .79; p < .05) were positively correlated. 5-HT and P₄ concentrations in follicular fluid increased progressively with the increase in follicular size (p < .05). Follicle diameter and E₂ (r = .85) and P₄ (r = .68) were correlated (p < .05). Since serotonin interacts with steroids, its role on steroidogenesis during growth of the dominant follicle may be suggested.

Hematochemical Patterns in Follicular Fluid and Blood Stream in Cycling Mares: A Comparative Note

The aim of this study was to verify the existence of possible cross-talk between biochemical contents of follicular fluid (FF) and systemic concentrations according to the follicular development of the metabolites: glucose (GLU), lactate (LACT), cholesterol (CHOL), triglycerides (TG), total bilirubin (T BIL), blood urea nitrogen (BUN), and creatinine (CREAT); enzymatic activities: gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and aspartate aminotransferase (AST); electrolytes: calcium (Ca), phosphorus (P), sodium (Na), chloride (Cl), potassium (K), magnesium (Mg), and iron (Fe); total proteins (TP) and their fractions: albumin (ALB), α1-, α2-, β-, and γ-globulins (GLOB) of FF and blood strain and their correlations with follicular size in cycling mares. Systemic concentrations of GLU, T BIL, BUN, Fe, TP, ALB, α-1, and α-2 and δ-GLOB and of ALP, GGT, and AST activities were higher than in the FF (P < .05); LACT, CHOL, and TG were higher in FF than systemic ones (P < .05). Glucose, CHOL, TG, LACT, and T BIL were higher in large follicles than in medium and small follicles (P < .05); however, BUN, Fe, ALP, and AST were lower in large follicles than in medium or small follicles (P < .05). Alkaline phosphatase, GGT, and AST activities decreased in medium and large follicles compared with small follicles (P < .05). These results suggest that the metabolic, enzymatic, electrolytic, and protein composition of FF of growing follicles could occur according to the bloodstream changes; hence, it is possible to presume that the nutritional environment of oocyte and follicular cells could improve the clinical diagnoses of infertility in the mare.

Testosterone, androstenedione and dehydroepiandrosterone concentrations in pregnant Spanish Purebred mare

Androgens modulate maternal ovarian activity, embryo implantation and correct placental development. The objective of this study was to establish reference values for testosterone (T), androstenedione (A₄) and dehydroepiandrosterone (DHEA) concentrations in pregnant mares. A total of 30 healthy Spanish Purebred mares with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. T, A₄ and DHEA concentrations were determined using EIA validated specifically for equines. T increased in the 2nd and 3rd month (P < 0.05), showing a plateau between the 4th and 6th month, decreased from the 7th to the 9th month (P < 0.05) and increased in the 10th month (P < 0.05), reaching the maximum value in the last month of pregnancy (P < 0.05). A₄ increased in the 2nd month (P < 0.05), reaching the maximum value in the 3rd month (P < 0.05), decreased in the 4th month, increasing in the 5th and 6th month (P < 0.05). From the 7th month the average values decreased until reaching the minimum at the end of gestation. DHEA progressively increased from the 1st to the 5th month, at which time the maximum mean value was reached (P < 0.05), after a decrease in the 6th and 7th month occurred (P < 0.05), reaching the minimum value in the last month of gestation. T, A₄ and DHEA were positive and significantly correlated (P < 0.05). The androgens analyzed in this study can be used as predictive markers of pregnancy in the mare.

Temporal relationships of GH, IGF-I and fructosamine concentrations in pregnant Spanish Purebred mares: A substantial contribution from the hormonal standpoint

Growth hormone (GH) and insulin-like growth factor (IGF-I) exert essential functions to maintain an adequate metabolic activity for correct placental and fetal development. Although fructosamine (FRUCT) is used in clinical evaluation to assess the glycaemic state, the relationships between GH, IGF-I and FRUCT remain unknown in the mare. Therefore, the objectives of this study were to evaluate the relationships among these parameters in pregnant mares. A total of 30 healthy Spanish Purebred mares, with an age range of 9.33 ± 3.31 years, were studied during the 11 months of gestation. Serum concentrations of GH, IGF-I and FRUCT were analyzed by EIA, competition ELISA and spectrophotometry, respectively. GH showed a biphasic pattern, the first occurred during 4th and 5th month and the second which was higher than the 1st one during the 7th, 8th and 9th month (P < 0.05). Compared to the 1st month, the IGF-I concentrations increased in the 2nd month (P < 0.05), decreased in the 3rd and 4th month and increased to reach the maximum average value in the 5th month (P < 0.05); after slight oscillations between the 6th and 8th month, IGF-I concentrations increased in the 9th month (P < 0.05), decreasing until the end of gestation. FRUCT increased progressively and significantly from the 6th month of gestation, reaching the maximum values in the last month of gestation (P < 0.05). These results suggest that alternative mechanisms other than GH and IGF-I could be involved in the regulation of glycaemic metabolism in pregnant mare.

The stress response of Ragusano donkey (Equus asinus) to different semen collection techniques

The aim of the present study was to characterize the stress response of donkeys to different semen collection techniques, comparing the physiological patterns of hormonal (adrenocorticotropic hormone: ACTH, cortisol) and biochemical variables (creatinine, total protein, urea, aspartate aminotransferase: AST, alanine aminotransferase: ALT), and routine seminal parameters and sexual behaviour. Twenty two healthy Ragusano donkeys were used and were randomly assigned to one of 2 groups based on different semen collection techniques. Group A was designated as the experimental group and included 16 donkeys submitted to semen collection by an artificial vagina (AV) "on the ground"; group B was designated as the control group, and included 6 donkeys submitted to semen collection by AV during the mount. The semen collection was performed in October, once a day for 10 consecutive days. Blood samples were collected in baseline conditions, before the onset of the treatments and within 30 min after, from the jugular vein of each subject. Two-way ANOVA showed a significant effect of semen collection technique and time points in group A for ACTH (p=0.0084), cortisol (p=0.0004) and creatinine (p=0.0131), with lower values after semen collection than before. A significant effect of semen collection technique and time points in group B for ACTH (p<0.0001) and cortisol (p<0.0001) was observed, with higher values after semen collection than before. The comparison between groups A and B values over different time points showed a significant effect after semen collection for ACTH (p<0.0001), cortisol (p<0.0001) and creatinine (p<0.0001), with the highest values in group B. This study provides the physiological evidence that semen collection on the ground in healthy donkeys could be used as an alternative strategy to induce a positive animal approach and economical advantages.

Changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise

Serotonin (5-HT) is a neurohormone transported from plasma into platelets and leukocytes by a specific transporter (SERT). While it is known that the brain 5-HT system is modulated by physical exercise, the peripheral serotoninergic response to exercise is not yet fully elucidated. In particular, this study aimed to evaluate changes in plasma 5-HT levels and equine leukocyte SERT expression in response to treadmill exercise in untrained horses. Analyses were carried out pre- and post-treadmill exercise. 5-HT plasma levels were analysed by HPLC. Leukocytes and platelets were isolated to perform Real Time PCR for the evaluation of SERT mRNA levels. Western blot was conducted for the detection of SERT protein levels. The presence of SERT in leukocytes was analysed by flow cytometry. The functionality of SERT on leukocytes was investigated by using paroxetine as inhibitor of 5-HT reuptake. Results showed a significant decrease in SERT levels after exercise in both leukocytes and platelets and a significant increase in plasma 5-HT levels. Flow cytometry revealed that SERT is functional in one specific horse leukocyte subpopulation, still not identified, and paroxetine was able to block 5-HT reuptake into leukocytes. The exercise may have induced an increased mobilization of free-tryptophan and a release of 5-HT from the stores in the blood. High concentrations of plasma 5-HT could have caused a reduction in SERT expression affecting cellular 5-HT storage/uptake. The increase of cortisol levels after treadmill exercise was not significant. Exercise modulates the peripheral serotonin metabolism. More research is needed to assess its physiological implications.

The contribution of total and free iodothyronines to welfare maintenance and management stress coping in Ruminants and Equines: Physiological ranges and reference values

In order to acquire a pattern of thyroid involvement in welfare maintenance in Ruminants and Equines, this review summarizes data concerning the reference values of total and free iodothyronines and their modifications in physiological conditions and in different management conditions (pregnancy, lactation, weaning, growth, isolation, restraint, shearing, confinement and transportation). Thyroidal and extrathyroidal tissues efficiently respond to management practices, giving a differentiated contribution to circulating iodothyronine changes. The hormonal response could be mainly attributed to the intracellular deiodination of T₄ to T_3. Triiodothyronine (T₃) and free iodothyronines (fT₃ and fT₄) result more responsive to management stress, showing different pattern with species and to various conditions, as to environmental conditions in which activities are performed. Intrinsic seasonal changes of iodothyronines and a significant pregnancy effect for T₃ were recorded in mares. Higher, although not significant, T₃ and T₄ concentrations in barren than pregnant mares were observed in donkeys. A positive significant correlation between T₃ and T₄ was described only in pregnant donkeys. Moreover, a significant effect of season on T₃ and fT₃ changes was observed both in pregnant and barren donkeys. A significant lactating effect compared with nonlactating stage for T₃ and T₄ was recorded in mares. In growing foals, body weight (BW) and age were positively correlated with T₃ and negatively correlated with T₄, fT₄ and fT₃. Weaning effects were shown for T₃ and fT₄ concentrations, indicating that weaning represents a severe stress and the presence of conspecific does not reduce psychological stress in this phase. Lambs showed significant decreased T₃ and elevated T₄ concentrations two weeks after weaning, with higher concentrations in both males and females compared to 24 h. Significant positive correlations were observed between BW and T₄, fT₃ and fT₄ concentrations in lambs. A T₃ decrease was detected after isolation, such as induced by confinement and weaning in lambs. Higher T₃ concentration after restraint and shearing than after isolation and significant increases in T₄, fT₃ and fT₄ values after restraint and shearing were recorded. The basal concentrations of fT₃ in both the inexperienced and experienced transported horses were significantly higher than in untransported experienced horses. Moreover, increases of T_3, T₄ and fT₄ after short road transportation, and significant correlations between T₃ and rectal temperature (RT), body weight (BW) and heart rate (HR), confirmed their important role in coping strategy. Thyroid responsiveness to short transport is similar in domestic donkeys and horses, with a preferential release of T₃ in horses. A greatest and constant release of T₃ and T₄, although differentiated, after simulated transportation and after conventional transport of horses confirmed that the degree of stress induced by confinement and additional stressful stimuli associated to road transportation could differently influence the iodothyronine release. Temperamental Limousin young beef bulls showed lower T₄ and fT₄ concentrations after prolonged transportation than calm subjects, and a concomitant decrease of circulating ACTH, cortisol, T₃ and fT₃ concentrations, probably induced by down regulation of HPA axis and cortisol negative feedback. These data reinforce the importance of taking into account the evaluation of iodothyronines, and notably of T₃, as markers of welfare and stress and their role in ensuring energy homeostasis and productive and reproductive performances in Ruminants and Equines.

Comparison of Acute versus Chronic Stress Responses to Different Housing’s Systems of Cats

Background: The hypothalamic-pituitary-adrenal (HPA) axis and functional systems undergo the assessment of stress levels throughout living environments, contributing to avoid side effects to well-being in domestic animals, including pets. Cortisol represents the most important glucocorticoid found in felis and it is frequently used as standard marker in stress research. The purpose of the present study was to compare the adrenal and haematological patterns of cats, by taking into account the effects of different housing’s systems. The hypothesis was to find a different coping strategies, according to different housings.Materials, Methods & Results: For this study a total of 50 cats were selected on the basis of the breed: European domestic short hair cats, age ranged between 22 and 30 months and housing’s systems, represented by cattery and/or households, respectively. On these basis, cats were distinguished into two groups, represented by group A: 22 cats living in cattery, and group B: 28 cats living in households. Blood samples were collected twice a week, for two consecutive days, during one month and subsequently analysed for haematological analysis and cortisol concentrations. Group B showed higher cortisol concentrations (P < 0.01), Red Blood Cell (P < 0.05), Packed Cell Volume (P < 0.001), Platelets (P < 0.01), Heart Rate and Respiratory Rate (P < 0.05) values, and lower White Blood Cell (P < 0.001) than group A.Discussion: This observational study showed that cats housed in the households group showed higher cortisol, RBC, PCV, Plt, HR and RR values, and lower WBC rather than cattery’s cats.  Another point is that males showed higher RBC, PCV, WBC and Plt than females, irrespective of different housing’s systems. The significant lower threshold of cortisol levels in cattery’s cats than household’s cats could suggest that these subjects were probably totally accustomed to cattery’s environment; though these animals were daily stimulated by predictable stimuli and manipulations, characterized by handling and husbandry routine, regular feeding and cleaning times, standard caretaking. On the other hand, the higher cortisol concentrations observed in household’s cats could be due to the different environmental stimuli, characterized by unpredictable handling, modified caretaking, presence of irregular talking, petting and manipulations by owners, which promote probably the expression of species and appropriate behaviour with stimulating activities. The significant highest RBC and PCV values in subjects of group B could be explained on the basis of the more intense activity of these subjects, according to the access to outdoor area. These concomitant higher values were corroborated in the present study by the not surprising positive and significant correlation observed between corresponding RBC and PCV values. The higher PCV values observed in cats of group B could be suggest that their daily frequent activity induced a physiological erythrocytosis, compared to sedentary cattery’s cats. The hypothesis that the home represented more rousing than cattery setting was assessed by the physiological and consistent higher cortisol, RBC, PCV, Plt, HR and RR displayed in the home environment; The only difference between the two groups was that environmental stimulus (chronic stress) was cattery for group A, whereas household for group B. Obtained data indicate that there was a marked benefit in to establish a personnel-cat relationship in addition to the traditionally owner-cat relationship, providing physiological coping strategies in both cattery and home cats; this was corroborate in the present study by the wide but physiological cortisol range. This study indicates that predictability, familiarity and unpredictability are significantly associated with environmental stimuli and with quality of pets’ life.

Effect of transportation on the sympatho-adrenal system responses in horses

The objective of current study was to evaluate the effect of transportation stress on the circulating adrenaline (A), noradrenaline (NA) and dopamine (DA) responses of stallions, according to the different distances. Forty-two stallions were studied before and after road transportation of 100, 200 and 300km, for a period of 1-3h. An increase in plasma A after 100km (P<0.001) was observed. A similar result was seen in plasma NA after 100km (P<0.001), and 300km (P<0.001). Increases in plasma DA after 100 and 200km (P<0.0001) were observed, with a decrease after 300km (P<0.0001). Significant interactions among groups and times for A (P<0.0001), NA (P<0.0006) and DA (P<0.0001) changes were observed. These results indicate that the sympatho-adrenal system response of horses was greater after short (100km), than medium-longer period of transportation (200 and 300km). This may indicate an adaptation process during transport, considering A and NA as the primary candidate neurotransmitters for the maintenance of homeostatic process to alleviate the effects of the perceived transportation stress.

Total and free iodothyronine changes in response to transport of Equidae (Equus asinus and Equus caballus)

In this study the effects of short distance road transport on total and free iodothyronine changes in 12 stallions (Equus asinus and Equus caballus) were evaluated. Donkeys (n = 6) and horses (n = 6) were transported for a distance of 50 km. Blood samples were collected 1 week before transport in basal conditions, 1 week later immediately before loading, and after transport and unloading. After transport, donkeys showed significant increases in circulating T4 (P≤0.01), fT3 (P≤0.001), and fT4 (P≤0.01) levels; while horses had significant increases in circulating T3, fT3 and fT4 (P≤0.01) levels. Compared to donkeys' values, horses showed lower T4 values in basal condition, before and after transport (P≤0.001); higher fT3 values in basal condition and before (P≤0.001), and lower values (P≤0.001) after transport; higher fT4 values (P≤0.001) in basal condition. The results indicate that short road transport of donkeys and horses induces the activation of the thyroid gland, with the same release of fT3 and fT4 iodothyronines, but with different preferential release of T3 in horses and T4 in donkeys after transport.

Influence of training and competitive sessions on peripheral β-endorphin levels in training show jumping horses

Aim:

To investigate the effects of training sessions on circulating β-endorphin changes in sport horses before and after competition and to ascertain whether competition would affect this response.

Materials and Methods:

A total of 24 trained jumping horses were randomly assigned to one of two training groups: Group A (competing) and Group B (not competing). To determined plasma β-endorphin concentrations, two pre- and post-competition training weeks at aerobic workout and two competitive show jumping event days at anaerobic workout were measured before, 5 and 30 min after exercise. Exercise intensity is described using lactate concentrations and heart rate. The circuit design, intensity, and duration of training sessions were the same for both groups.

Results:

In Group A, one-way analysis of variance for repeated measures (RM-ANOVA) showed significant effects of exercise on β-endorphin changes (F=14.41; p<0.001), only in the post-competition training sessions, while in Group B showed no significant effects. Two-way RM-ANOVA showed, after post-competition training sessions, a significant difference between Group A and Group B (F=6.235; p=0.023), with higher β-endorphin changes in Group A, compared to Group B. During the competitive show jumping sessions, one-way RM ANOVA showed significant effects of exercise on β-endorphin changes (F=51.10; p<0.001). The statistical analysis, in Group A, showed a significant difference between post-competition training and competitive exercise (F=6.32; p=0.024) with higher β-endorphin values in competitive sessions compared to those of post-competition training.

Conclusion:

Lactate concentrations seem to be the main factors being correlated with the raise of β-endorphin during anaerobic exercise of competitive events. Exercise of low intensity, as well as that one of training sessions, does not appear to stimulate a significant increased release of β-endorphin and it may depend on the duration of the exercise program. Moreover, the responses during exercise in the course of post-competition training sessions seem to be significantly different from those the pre-competition training. These data show that the preliminary competitive stress induced additional significant changes of β-endorphin pattern. It would reflect the need of a long-lasting modulation of fatigue and pain perception related to the effect of an additional physical and mental effort for the consecutive competitive and training sessions.

Pituitary-adrenocortical adjustments to transport stress in horses with previous different handling and transport conditions

Aim:

The changes of the hypothalamic pituitary adrenal (HPA) axis response to a long distance transportation results in increase of adrenocorticotropic hormone (ACTH) and cortisol levels. The purpose of the study was to quantify the level of short-term road transport stress on circulating ACTH and cortisol concentrations, related to the effect of previous handling and transport experience of horses.

Materials and Methods:

The study was performed on 56 healthy horses after short-term road transport of 30 km. The horses were divided into four groups, Groups A, B, C, and D, with respect to the handling quality: Good (Groups A and B), bad (Group D), and minimal handling (Group C) conditions. According to the previous transport, experience horses were divided as follows: Horses of Groups A and D had been experienced long-distance transportation before; horses of Groups B and C had been limited experience of transportation.

Results:

One-way RM-ANOVA showed significant effects of transport on ACTH changes in Groups B and C and on cortisol changes in both Groups A and B. Groups A and B showed lower baseline ACTH and cortisol values than Groups C and D; Groups A and B showed lower post-transport ACTH values than Groups C and D. Groups A, B, and C showed lower post-transport cortisol values than Group D. Only Groups A and B horses have shown an adequate capacity of stress response to transportation.

Conclusion:

The previous transport experience and quality of handling could influence the HPA axis physiological responses of horses after short-term road transport.

The outcome of the first stages of pregnancy on mares' bloodstream thyroid hormones

The objective of this study was to compare in detail the total and free iodothyronines' pattern of mares from the first ovulation of the year over an extended period of 12 weeks. A total of 20 mares were used in the study. The mares were classified into two groups: mares mated at the ovulation (n = 10) used as observational group and mares unmated at the ovulation (n = 10) used as control group. Serum total and free triiodothyronine (T3, fT3) and thyroxine (T4, fT4) levels were measured in baseline conditions at the first ovulation of year and once a week until 12 weeks later. For the experimental group, the first week of postovulation mating was considered as the first week of gestation. One-way analysis of variance showed a significant effect of time over 12 weeks for T3 (F = 2.44; P = 0.007) in pregnant mares, with the higher levels at the seventh and 12th weeks (P < 0.05) than baseline values, and for fT3 (F = 2.36; P = 0.009), with the higher levels at the 11th week (P < 0.05) than baseline values. Two-way analysis of variance showed a significant pregnancy effect compared with nonpregnancy stage for T3 (F = 15.82; P = 0.009), with the higher levels at the seventh and 12th weeks (P < 0.05) of pregnancy than that in nonpregnant values. Thus, it appears that, under similar environment, management and nutritional regime, the first trimester of pregnancy plays a dynamic role on the thyroid patterns by their anabolic activity; therefore, significant effects of time points on the T3 and fT3 concentrations probably may contribute to the control of early embryonic growth and development, before the onset of fetal thyroid activity. Considerable additional research, outwith the aim of this study, will be required to elucidate the mechanisms by which gestational age affects the physiological thyroid function in mares and/or fetus ratio in the first pregnancy stage.

Pituitary-Adrenal Axis Responses to Routine Management Procedures in Sheep (Ovis aries)

Background: Shearing is considered as a stressful factor in sheep, capable of causing some behavioural changes including variations of body condition and hormonal and haematochemical parameters. On these basis, circulating ACTH and cortisol concentrations were determined in sheep before and after exposure to aversive stimuli in order to evaluate the potential use of these hormones to objectively measure physical and mental stress responses to isolation, restraint and shearing.Materials, Methods & Results: Forty Pinzirita sheep, used as experimental group, were evaluated in baseline conditions, 24 h before isolation, restraint and shearing (T0), after isolation (T1), after restraint and shearing (T2), by taking into account the influence of previous shearing experience (just shorn). A control group of forty sheep (intact) was evaluated in baseline condition (T0). According to previous experience the experimental subjects were divided in two groups, respectively group A represented by 20 sheep (10 males and 10 females), aged 1-2 years, without previous shearing experience (intact); and group B represented by 20 sheep (10 males and 10 females), aged older than 2 years, previously exposed to shearing (just shorn). A control group C of 40 sheep splitted into two sub-groups represented by 10 intact males and 10 intact females, aged 1-2 years, and 10 males and 10 females just shorn, aged older than 2 years, was evaluated in baseline conditions (T0). Blood samples were collected 24 h before experimental practices (T0: 08:00 h), after 1 h after of isolation (T1) and after restraint and shearing, around an average of 5 min (T2). All samples were taken in quiet conditions by the same operator. Serum ACTH concentrations were assayed by a commercial radioimmunoassay (RIA). Serum cortisol concentrations were assayed by amplified Enzyme Immunoassay (EIA). Two-way RM ANOVA showed a significant effect of husbandry procedures on ACTH changes, with higher ACTH and cortisol concentrations of just shorn than intact males (F = 15.76;  P < 0.0001) and females (F = 17.34; P < 0.0005), and on cortisol changes, with higher cortisol concentrations of just shorn than intact males (F = 6.54; P < 0.01) and females (F = 22.66; P < 0.0001).Discussion: The highest ACTH and cortisol values after isolation, with an appreciable increase especially after restraint and shearing in just shorn sheep, showed that the previous shearing exposure could not induce a habituation to the stimulus, probably promoting a larger release of ACTH and cortisol hormones, so inducing an early and marked coping response to stress in just shorn specimens. Thus, it would appear that different ACTH and cortisol responses of sheep with or without previous shearing experience over the study period resulted in some significant differences when exposed to isolation, restraint and shearing, probably due to changes in pituitary-adrenal axis reactivity. Nevertheless, it is possible  to interpret the increase in ACTH and cortisol concentrations related to intrinsic endocrine control mechanisms as an increase due to a rise in the stressful stimulus or coping response. The magnitude of ACTH and cortisol changes following isolation, restraint and shearing suggests that measurements of both hormones are useful in assessing husbandry procedures stress in sheep, with marked elevations in just shorn sheep, indicating that experience can induce an early much larger coping response to stressful practice of shearing.