Plasma total T3 and T4 concentrations in bucks as affected by photoperiod

Todini, Luca; Delgadillo, J.A.; Debenedetti, A.; Chemineau, Philippe

doi:10.1016/j.smallrumres.2005.05.034

Cited by 12 publications

(8 citation statements)

References 12 publications

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“…The effects of daylength changes on plasma T4 concentrations were seen after a delay of several weeks and the T3:T4 ratio showed very marked variations, increasing during LD and decreasing during SD (Todini et al, 2006). Similar results were obtained by Lincoln et al (1980) in rams submitted to an alternance of 16 weeks of SD and 16 weeks of LD.…”

Section: Season Effectssupporting

confidence: 83%

“…Blood TH concentrations were high in spring (increasing daylength) and low in autumn (decreasing daylength), which was not fully explained by the changes in environmental temperature (Figure 2; Buys et al, 1990;Todini et al, 1992; McMillen, 1995: Clariget et al, 1998;Rhind et al, 2000;Taha et al, 2000;Villar et al, 2000a;Merchant and Riach, 2002;Souza et al, 2002; Blaszczyk et al, 2004;Zamiri and Khodaei, 2005;Menegatos et al, 2006;Todini et al, 2006). It seems that when the temperature ranges are not extreme (mild climate, indoor housing, shelter in the night time), the effect of photoperiod and season-dependent TH profiles (mainly related to the daylength changes) are present.…”

Section: Season Effectsmentioning

confidence: 99%

“…In the Sahel desert, plasma T3 and T4 levels did not change significantly from the beginning of the cool season (December) until the end of the dry warm season (May), but a highly significant rise of both hormones was observed at the onset of the humid warm season (June) (Assane and Sere, 1990). It can be supposed that an enhanced thyroid activity during the humid warm season in such environments is functional for the animals facing the increased availability of food (quantity and quality), following the seasons characterised by food shortage.Blood TH concentrations were high in spring (increasing daylength) and low in autumn (decreasing daylength), which was not fully explained by the changes in environmental temperature (Figure 2; Buys et al, 1990;Todini et al, 1992; McMillen, 1995: Clariget et al, 1998;Rhind et al, 2000;Taha et al, 2000;Villar et al, 2000a;Merchant and Riach, 2002;Souza et al, 2002; Blaszczyk et al, 2004;Zamiri and Khodaei, 2005;Menegatos et al, 2006;Todini et al, 2006). It seems that when the temperature ranges are not extreme (mild climate, indoor housing, shelter in the night time), the effect of photoperiod and season-dependent TH profiles (mainly related to the daylength changes) are present.…”

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confidence: 99%

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Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Todini

2007

Animal

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Appropriate thyroid gland function and thyroid hormone activity are considered crucial to sustain the productive performance in domestic animals (growth, milk or hair fibre production). Changes of blood thyroid hormone concentrations are an indirect measure of the changes in thyroid gland activity and circulating thyroid hormones can be considered as indicators of the metabolic and nutritional status of the animals. Thyroid hormones play a pivotal role in the mechanisms permitting the animals to live and breed in the surrounding environment. Variations in hormone bioactivity allow the animals to adapt their metabolic balance to different environmental conditions, changes in nutrient requirements and availability, and to homeorhetic changes during different physiological stages. This is particularly important in the free-ranging and grazing animals, such as traditionally reared small ruminants, whose main physiological functions (feed intake, reproduction, hair growth) are markedly seasonal. Many investigations dealt with the involvement of thyroid hormones in the expression of endogenous seasonal rhythms, such as reproduction and hair growth cycles in fibre-producing (wool, mohair, cashmere) sheep and goats. Important knowledge about the pattern of thyroid hormone metabolism and their role in ontogenetic development has been obtained from studies in the ovine foetus and in the newborn. Many endogenous (breed, age, gender, physiological state) and environmental factors (climate, season, with a primary role of nutrition) are able to affect thyroid activity and hormone concentrations in blood, acting at the level of hypothalamus, pituitary and/or thyroid gland, as well as on peripheral monodeiodination. Knowledge on such topics mirror physiological changes and possibly allows the monitoring and manipulation of thyroid physiology, in order to improve animal health, welfare and production.Keywords: goats, nutrition, seasons, sheep, thyroid hormones IntroductionAppropriate thyroid gland function and activity of thyroid hormones (TH) are considered crucial to sustain the productive performance in domestic animals (growth, milk, hair fibre production) and circulating TH can be considered as indicators of the metabolic and nutritional status of the animals (Riis and Madsen, 1985;Todini et al., 2007). Changes of blood TH concentrations are an indirect measure of the changes in thyroid gland activity. Many papers report marked seasonal variation in thyroid activity and in blood TH concentration. These hormone variations are particularly important in the free-ranging and grazing animals, whose main physiological functions (feed intake, reproduction, hair growth) are markedly seasonal. This is the case of small ruminants traditionally reared. Such variations in hormone concentration, in fact, allow the animals to adapt their metabolic balance to different environmental conditions, variations in nutrient requirements and availability, and to homeoretic changes during different physiological stages.The present paper aims to re...

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Section: Season Effectssupporting

confidence: 83%

Section: Season Effectsmentioning

confidence: 99%

mentioning

confidence: 99%

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Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Todini

2007

Animal

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193

142

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“…In the present study, the supposed inhibitory effect of the increasing environmental temperature may have been overcome by the increasing day length. In fact, treatment with artificial photoperiod cycles clearly affected concentrations of circulating TH (Todini et al, 2006) and the light-induced increase in circulating hormones could play a role in sustaining advanced lactation. The galactopoietic effect of increasing day length have been demonstrated in dairy ruminants submitted to artificial photoperiod (Dahl et al, 2000(Dahl et al, , 2015.…”

Section: Discussionmentioning

confidence: 99%

Thyroid Hormones in Donkey Blood and Milk: Correlations with Milk Yield and Environmental Temperatures

Todini

Salimei

Malfatti

et al. 2015

Italian Journal of Animal Science

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Thyroid hormones (TH) are the primary endocrine stimulators of non-shivering thermogenesis and are known to stimulate lactation. Triiodothyronine (T3) is the bioactive form, mainly derived by deiodination of thyroxine (T4), and the free quote (unbound to plasma proteins) is immediately bioavailable. This study aimed to evaluate potential relationships among TH in the blood, triiodothyronine in the milk (T3M), milk yield and environmental temperature in March to July for 8 lactating donkeys. Milk yield and blood TH concentrations changed significantly over time, whereas T3M was rather stable among individuals and not affected by time of sampling. Free T3 was not correlated with free T4 or with total TH in the blood, but it was weakly correlated with T3M. No relationship was found between blood TH and milk yield, which was negatively correlated with T3M. Thus, the absolute quantity of bioactive hormone in milk secretion is maintained. Milk yield was positively correlated with the free/total T3 and free T3/free T4 ratios, thus in turn with the relative quote of the circulating bioactive hormone. Circulating T3/T4 ratios were negatively correlated with environmental temperature. It is concluded that environmental temperature, in the range of the present study (-2 to 35°C), does not significantly entrain thyroid gland activity, which is affected more by other factors, such as inter-individual variations and physiological status (i.e., stage of lactation). However, increases in environmental temperature most likely induce decreases in deiodinase activity at the peripheral tissue level, as indicated by the decrease in the T3/T4 ratios in the blood.

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“…The thyroid hormones (T 3 and T 4 ) have profound physiological effects including development, growth, metabolic activity, and production performance of animals (1,2). T 3 and T 4 play a particular role in energy homeostasis and skeletal muscle development (3,4).…”

Section: Introductionmentioning

confidence: 99%

Correlation of blood triiodothyronine (T3) level with some production traits in male goat kids

Abdoun¹,

Samara²,

Okab³

et al. 2018

Turk J Vet Anim Sci

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Thyroid hormones are known for their stimulation of feed efficiency and growth performance in different farm animals. More interestingly, the level of thyroid hormones is influenced by selection for growth in some animal species. Therefore, it was the aim of the current study to investigate whether a correlation exists between the blood triiodothyronine (T 3 ) level and some production traits (daily feed intake, average daily gain, and feed conversion ratio). To test this hypothesis, six male goat kids (21.9 ± 2.4 kg; 5 months old) belonging to Aardi, Damascus, and their cross breed (two kids from each genotype) were used in the current study. The obtained results revealed a positive linear correlation of plasma T 3 level with both average daily feed intake and average daily gain with correlation coefficients of 99% and 97%, respectively (P ≤ 0.001). On the other hand, feed conversion ratio was negatively correlated to the plasma T 3 level with a correlation coefficient of 81% (P = 0.05). The obtained results indicate the possible use of blood T 3 level for the prediction of feed intake, daily body weight gain, and feed conversion ratio in addition to the possible use of blood T 3 level as a criterion of breeding selection for growth performance in the future.

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Plasma total T3 and T4 concentrations in bucks as affected by photoperiod

Cited by 12 publications

References 12 publications

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Thyroid hormones in small ruminants: effects of endogenous, environmental and nutritional factors

Thyroid Hormones in Donkey Blood and Milk: Correlations with Milk Yield and Environmental Temperatures

Correlation of blood triiodothyronine (T3) level with some production traits in male goat kids

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