Serum concentration of thyroid hormones in crioula lanada serrana ewes in gestation and lactation

Abstract

SUMMARYThe effects of gestation and lactation on the dynamics of the thyroid hormones, triiodothyronine (T 3 ) and thyroxine (T 4 ) were evaluated in Crioula Lanada Serrana ewes from the plateau region in Santa Catarina -Brazil. To evaluate the effects of gestation, twenty four ewes were randomly divided into groups I and II. Group I was composed of 12 pregnant ewes and the control group (II) was composed of 12 non-pregnant ewes. The effects of lactation were evaluated in the same ewes of group I after parturition (LE) and in the control group (NL). Blood samples were taken in the first, second and third periods of gestation, at parturition, and at 30, 60 and 90 days of lactation. T 3 and T 4 concentrations were determined by radioimmunoassay (RIA). Pregnant ewes showed lower serum concentrations of T 3 and T 4 than those of non-pregnant ewes. At parturition, there was no significant difference in T 3 concentrations between groups I and II (p>0.05). During lactation, serum T 3 concentrations were lower (p≤0.05) in LE than in NL ewes. Serum T 3 concentrations were greater (p≤0.05) at lambing than during the lactation periods. Serum T 4 concentrations in LE at parturition did not differ (p>0.05) from those of NL ewes. During lactation, T 4 concentrations of LE were lower (p≤0.05) than those of the NL ewes. The results of this study have shown that gestation causes a variation in the T 3 and T 4 serum concentrations, and that lactation results in a decrease of serum concentrations of T 3 and T 4 in Crioula Lanada Serrana ewes. RESUMOOs efeitos da gestação e lactação sobre a dinâmica dos hormônios tireoidianos triiodotironina (T 3 ) e tiroxina (T 4 ) foram avaliados em ovelhas Crioula Lanada Serrana na região do Planalto Serrano Catarinense. Para avaliar os efeitos da gestação, foram utilizadas vinte e quatro ovelhas distribuídas aleatoriamente em dois grupos. O grupo I foi formado por 12 ovelhas gestantes e o grupo controle por 12 ovelhas não gestantes (grupo II). Os efeitos da lactação foram avaliados nas mesmas ovelhas do grupo I após a parição (LE) e no grupo controle (NL). Foram colhidas amostras sanguíneas no primeiro, segundo e terceiro terço da gestação, ao parto e aos 30, 60 e 90 dias de lactação. As concentrações de T 3 e T 4 foram determinadas por radioimunoensaio (RIA). As ovelhas gestantes apresentaram concentrações séricas de T 3 e T 4 inferiores àquelas não gestantes. Ao parto não houve diferença significativa nas concentrações de T 3 entre os grupos I e II (p>0,05). Durante a lactação as concentrações Archivos de zootecnia vol. 59, núm. 228, p. 510

Thyroid hormone concentrations in relation to age, sex, pregnancy, and perinatal loss in bottlenose dolphins (Tursiops truncatus)

“…In adults, other factors besides a mismatch in age (e.g., lactation and stage of estrous cycle) may influence the apparent difference between sexes and inconsistencies among T 4 and T 3 Although lactational status was not examined in the present study, concentrations of total and free T 4 were lower in lactating than in non-lactating, non-pregnant bottlenose dolphins (Fair et al, 2011) and bowhead whales (Rosa et al, 2007). The results in small populations of wild dolphins and whales correspond with a transient, mild condition of hypothyroidism during early lactation reported in humans (Leung et al, 2011), sheep, goats (Todini, 2007), and horses (Katovich et al, 1974) and support the concept that thyroid hormone concentrations are influenced by stage of lactation as reported in cattle (Gueorguiev, 1999) and sheep (Colodel et al, 2010). Reportedly, higher concentrations of T 3 have been detected during the luteal phase compared to the follicular phase in women (Girdler et al, 1995) and ewes (Todini, 2007), and higher total and free T 4 was observed during estrus in ewes and goats (Todini, 2007).…”

“…However, the relationships between these factors and thyroid hormones was not always consistent within or between species, perhaps because of the different environmental conditions, relatively small numbers of animals, unknown pregnancy status, and lack of longitudinal samples within studies. In comparative studies of humans and domestic animal species, thyroid hormones appear to be influenced by age, sex, and pregnancy status (Colodel et al, 2010;Fantz et al, 1999;Feldman and Nelson, 2004;Glinoer et al, 1990;Harada et al, 1979;Hübner et al, 2005;Kapelari et al, 2008;Refsal et al, 1984) and, are therefore taken into consideration during clinical examination and diagnosis of potential thyroid disorders.…”

The impact of melatonin administration on the fertility performance and several relating parameters during the breeding season in the Arabi ewes

“…Whereas, the reason for the decreasing of this hormone in the last month that fetus became more developed and needs more iodine to the synthesis it is thyroxin hormone, the fetus will take iodine from the only available source (mother`s circulation) (33,34), and that will cause a negative effect on mother`s thyroxin synthesis. Similar results were also observed by Colodel et al (35), who reported that thyroxin level increased in the serum of pregnant Lanada Serrana ewes during mid-gestation and decreased during the end of it. In addition, there was an increase in the concentration of cortisol in first and second months of gestation in comparison with other months.…”

Selenium and Iodine Status of two Camel Breeds (Camelus Dromedaries) Raised Under Semi Intensive System in Saudi Arabia

“…A wide variation of T3 and T4 in camels and other ruminant were found and reported by many researchers because of many undefined factors. Levels of T3 and T4 for both breeds were similar to the levels reported by Nazifi et al (2009) (166.24±7.12 ng/dL and 12.30±0.412 µg/dL, respectively) for Iranian camels, but higher than cows at different physiological status (Mohebbi-Fani et al (2009), T4 from 4.23 to 7.03 µg/dL and T3 from 69.21 to 106.08 ng/dL; ewes (Colodel et al, 2010) T4 2.64 to 4.91 µg/dL and T3 from 137 to 196 ng/dL; and water buffalo (Tajik et al, 2010), T4 0.489±0.01 µg/dL and T3 157.50± 7.12 ng/dL.…”