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Dechow C, Baumrucker C, Bruckmaier R, Blum J. Blood plasma traits associated with genetic merit for feed utilization in Holstein cows. J Dairy Sci 2017; 100:8232-8238. [DOI: 10.3168/jds.2016-12502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 06/04/2017] [Indexed: 11/19/2022]
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Todini L, Salimei E, Malfatti A, Brunetti VL, Fantuz F. Thyroid Hormones in Donkey Blood and Milk: Correlations with Milk Yield and Environmental Temperatures. ITALIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.4081/ijas.2015.4089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Bertoni G, Lombardelli R, Piccioli-Cappelli F, Blum J. Basal levels and diurnal variations of some hormones and metabolites in blood of dairy cows treated daily with rbst in early and late lactation. ITALIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.4081/ijas.2002.127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kahl S, Elsasser TH, Rhoads RP, Collier RJ, Baumgard LH. Environmental heat stress modulates thyroid status and its response to repeated endotoxin challenge in steers. Domest Anim Endocrinol 2015; 52:43-50. [PMID: 25804834 DOI: 10.1016/j.domaniend.2015.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/19/2015] [Accepted: 02/21/2015] [Indexed: 11/27/2022]
Abstract
The objective of this study was to evaluate in cattle, the effects of acute exposure to a heat stress (HS) environment on the status of the pituitary (thyrotropin, TSH)-thyroid (thyroxine, T4)-peripheral tissue T4 deiodination (type 1 5'-deiodinase [D1]; triiodothyronine [T3]; reverse-triiodothyronine [rT3]) axis, and the further response of this pituitary-thyroid-peripheral tissue axis (PTTA) to perturbation caused by the induction of the proinflammatory innate immune state provoked by the administration of gram-negative bacteria endotoxin (lipopolysaccharide [LPS]). Ten steers (318 ± 49 kg body weight) housed in controlled environment chambers were subjected to either a thermoneutral (TN: constant 19°C) or HS temperature conditions (cyclical daily temperatures: 32.2°C-40.0°C) for a total period of 9 d. To minimize the effects of altered plane of nutrition due to HS, steers in TN were pair-fed to animals in HS conditions. Steers received 2 LPS challenges 3 d apart (LPS1 and LPS2; 0.2 μg/kg body weight, intravenously, Escherichia coli 055:B5) with the first challenge administered on day 4 relative to the start of the environmental conditioning. Jugular blood samples were collected at 0, 1, 2, 4, 7, and 24 h relative to the start of each LPS challenge. Plasma TSH, T4, T3, and rT3 were measured by radioimmunoassay. Liver D1 activity was measured in biopsy samples collected before the LPS1 (0 h) and 24 h after LPS2. Before the start of LPS1, HS decreased (P < 0.01 vs TN) plasma TSH (40%), T4 (45.4%), and T3 (25.9%), but did not affect rT3 concentrations. In TN steers, the LPS1 challenge decreased (P < 0.01 vs 0 h) plasma concentrations of TSH between 1 and 7 h and T4 and T3 at 7 and 24 h. In HS steers, plasma TSH concentrations were decreased at 2 h only (P < 0.05), whereas plasma T3 was decreased at 7 and 24 h (P < 0.01). Whereas plasma T4 concentrations were already depressed in HS steers at 0 h, LPS1 did not further affect the levels. Plasma rT3 concentrations were increased in all steers at 4, 7, and 24 h after LPS1 (P < 0.01). The patterns of concentration change of T4, T3, and rT3 during LPS2 mirrored those observed in LPS1; the responses in plasma TSH were of smaller magnitude than those incurred after LPS1. The LPS challenges reduced (P < 0.01) hepatic activity of D1 in all animals but no differences were observed between steers subjected to TN or HS environment. The data are consistent with the concept that acute exposure of cattle to a HS environment results in the depression of the pituitary and thyroid components of the PTTA, whereas a normal capacity to generate T3 from T4 in the liver is preserved. The data also suggest that LPS challenge further suppresses all components of the PTTA including liver T3 generation, and these PTTA perturbations are more pronounced in steers that encounter a HS exposure.
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Affiliation(s)
- S Kahl
- U.S. Department of Agriculture, Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA.
| | - T H Elsasser
- U.S. Department of Agriculture, Animal Biosciences and Biotechnology Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705, USA
| | - R P Rhoads
- Animal Sciences Department, William J. Parker Agricultural Research Center, University of Arizona, Tucson, AZ 85721, USA
| | - R J Collier
- Animal Sciences Department, William J. Parker Agricultural Research Center, University of Arizona, Tucson, AZ 85721, USA
| | - L H Baumgard
- Animal Sciences Department, William J. Parker Agricultural Research Center, University of Arizona, Tucson, AZ 85721, USA
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Thyroid hormones in milk and blood of lactating donkeys as affected by stage of lactation and dietary supplementation with trace elements. J DAIRY RES 2012; 79:232-7. [DOI: 10.1017/s0022029912000118] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The traditional utilization of donkeys (Equus asinus) as dairy animals has recently attracted substantial scientific interest with regard to human nutrition. Donkey milk is well tolerated by infants with cows’ milk allergy, useful in the treatment of human immune-related diseases, in the prevention of atherosclerosis, and in-vitro studies showed an anti-proliferative effect. Active 3-3′-5-triiodothyronine (T3) in colostrum and milk could play different physiological roles, systemic and paracrine, for both the mother and the suckling offspring. The aim was to evaluate whether thyroid hormones (TH) concentrations in milk and blood of lactating donkeys change with the advancing lactation and whether they can be affected by dietary supplementation with several trace elements, some of them directly involved with TH synthesis (I), metabolism (Se) and action (Zn). Sixteen lactating jennies were divided into two groups (CTL and TE). Mixed feed for TE was added with Zn, Fe, Cu, Mn, I, Se and Co. Every 2 weeks milk and blood samples were collected at 11·00. Total concentrations of T3 in milk (T3M) and T3 and T4 in plasma (T3P and T4P) were assayed using ELISA kits, validated for the donkey species. T3M was not correlated with TH concentrations in blood, did not change with the stage of lactation, and was significantly higher in TE (4·09±0·07 ng/ml, mean±se) than in CTL group (3·89±0·08 ng/ml). T4P (81·8±5·2 ng/ml) and T3P (15·2±1 ng/ml) significantly changed with time, but were not significantly affected by dietary treatment. T3P/T4P ratio was significantly lower in TE group. This study indicates that in donkey milk the concentration of T3, a human-like bioactive compound, can be affected by trace elements intake.
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Capuco A, Binelli M, Tucker H. Neither bovine somatotropin nor growth hormone-releasing factor alters expression of thyroid hormone receptors in liver and mammary tissues. J Dairy Sci 2011; 94:4915-21. [DOI: 10.3168/jds.2010-4098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Accepted: 06/22/2011] [Indexed: 01/07/2023]
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Flores R, Looper ML, Rorie RW, Hallford DM, Rosenkrans CF. Endocrine factors and ovarian follicles are influenced by body condition and somatotropin in postpartum beef cows1,2. J Anim Sci 2008; 86:1335-44. [DOI: 10.2527/jas.2007-0574] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Effects of the Brown Seaweed Residues Supplementation on In Vitro Fermentation and Milk Production and Composition of Lactating Dairy Cows. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2004. [DOI: 10.5187/jast.2004.46.3.373] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Boutinaud M, Rousseau C, Keisler DH, Jammes H. Growth hormone and milking frequency act differently on goat mammary gland in late lactation. J Dairy Sci 2003; 86:509-20. [PMID: 12647957 DOI: 10.3168/jds.s0022-0302(03)73629-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In ruminants, milk yield can be affected by treatment with growth hormone (rbGH) and/or changes in frequency of milking. Frequent milkings encourage the maintenance of lactation, whereas infrequent milkings result in mammary involution. Our objective was to evaluate the influence of rbGH treatment and milking frequency on mammary gland morphology and milk composition. After adaptation to twice-daily milkings, six Saanen goats in late lactation were milked once daily from one udder-half and thrice-daily from the other udder-half. Concurrently, three of the six goats received daily injections of rbGH. After 23 d of treatment, milking frequency significantly affected milk yield (+8% vs. -26% for thrice- vs. once-daily milking). Additionally, treatments of rbGH increased milk yield from thrice-daily milked udder-halves (+19%), but failed to abate the reduction in milk yield from once-daily milked udder-halves (-31%). Mammary glands were heavier in the frequently milked udder-halves and in GH-treated goats. Based on histological and DNA analysis of mammary tissues, it was determined that milking frequency clearly affected epithelial cell numbers and alveolar diameter, whereas rbGH induced a potential cell hypertrophy and only a tendency to increase and/or maintain the mammary cell number. RNA concentration and kappa casein gene expression were not affected by treatments. In udder-halves milked once-daily, low casein:whey protein ratios, high Na+:K+ ratios, and high somatic cell counts (SCC) were indicative of changes in epithelial permeability, which rbGH treatment facilitated. The present data suggest that milking frequency and exogenous treatments of rbGH use different cellular mechanisms to influence mammary gland morphology and milk production.
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Affiliation(s)
- M Boutinaud
- Biologie Cellulaire et Moléculaire, INRA, 78352 Jouy en Josas Cedex, France.
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Nikolić JA, Kulcsár M, Kátai L, Nedić O, Jánosi S, Huszenicza G. Periparturient endocrine and metabolic changes in healthy cows and in cows affected by mastitis. JOURNAL OF VETERINARY MEDICINE. A, PHYSIOLOGY, PATHOLOGY, CLINICAL MEDICINE 2003; 50:22-9. [PMID: 12650505 DOI: 10.1046/j.1439-0442.2003.00500.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transition from pregnancy to lactation in dairy cows involves considerable metabolic adaptation. Additional stress is incurred during infections such as periparturient mastitis. Multiparous Holstein-Friesian cows kept under normal production conditions (n = 15) were used to evaluate changes in circulating metabolite and hormone concentrations from 5 days before to 5 days after calving. Insulin-like growth factor binding protein (IGFBP) profiles were also monitored. Marked time-related changes were observed for plasma thyroid hormone, IGF, cortisol, insulin, beta-hydroxybutyrate (BHB) and non-esterified fatty acid (NEFA) concentrations but not for plasma leptin. A decrease in IGF-II concentration and maximal intensity of the putative IGFBP-1 band occurred at parturition. When compared with the five healthy cows,low IGF-II levels were prolonged to day 2 post-partum in five cows with Escherichia coli-associated mastitis. However, marked decreases in IGFBP-2 band intensity were evident only in two of the four cases examined. Individual total ligand (IGF-I + IGF-II) concentration and IGFBP pattern prepartum were largely regained 5 days post-partum in all cows. Hormone and metabolite concentrations in the two cows with Staphylococcus aureus-associated mastitis were very similar to those in the five healthy cows. Plasma thyroxine (T4) was lower 2 days prepartum in the cows, which later developed Gram-negative mastitis. Multiregression analysis showed that variance in T4 concentration was significantly and independently associated with triiodothyronine (T3) and IGF-I positively and with cortisol negatively (R2 = 0.648). This study confirms the close inter-relationship between the thyroid hormone and IGF axes in cattle and indicates possible effects of Gram-negative mastitis infection on IGF-II metabolism.
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Affiliation(s)
- J A Nikolić
- INEP - Institute for the Application of Nuclear Energy, Zemun, Yugoslavia.
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Chadio S, Menegatos J, Zervas G, Goulas C, Deligeorgis S, Kalogiannis D. Pituitary responsiveness to gonadotropin- and thyrotropin-releasing hormones in goats treated with recombinant bovine somatotropin. Small Rumin Res 2002. [DOI: 10.1016/s0921-4488(02)00188-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kahl S, Elsasser TH, Sartin JL, Fayer R. Effect of progressive cachectic parasitism and growth hormone treatment on hepatic 5'-deiodinase activity in calves. Domest Anim Endocrinol 2002; 22:211-21. [PMID: 12044611 DOI: 10.1016/s0739-7240(02)00127-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thyroid status is compromised in a variety of acute and chronic infections. Conversion of thyroxine (T(4)) into the metabolically active hormone, triiodothyronine (T(3)), is catalyzed by 5'-deiodinase (5'D) mainly in extrathyroidal tissues. The objective of this study was to examine the effect of protozoan parasitic infection (Sarcocystis cruzi) on hepatic 5'D (type I) activity and plasma concentrations of T(3) and T(4) in placebo- or bovine GH (bGH)-injected calves. Holstein bull calves (127.5+/-2.0 kg BW) were assigned to control (C, ad libitum fed), infected (I, 250,000 S. cruzi sporocysts per os, ad libitum fed), and pair-fed (PF, non-infected, fed to intake of I treatment) groups placebo-injected, and three similar groups injected daily with pituitary-derived bGH (USDA-B-1, 0.1mg/kg, i.m.) designated as C(GH), I(GH) and PF(GH). GH injections were initiated on day 20 post-infection (PI), 3-4 days prior to the onset of clinical signs of the acute phase response (APR), and were continued to day 56 PI at which time calves were euthanized for liver collection. Blood samples were collected on day 0, 28, and 55 PI. Alterations in nutritional intake did not affect type I 5'D in liver. Treatment with bGH increased (P<0.05) 5'D activity in C (24.6%) and PF (25.5%) but not in I calves. Compared to PF calves, infection with S. cruzi reduced 5'D activity 25% (P<0.05) and 47.8% (P<0.01) in placebo- and bGH-injected calves, respectively. Neither nutrition nor bGH treatment significantly affected plasma concentrations of T(4) and T(3) on day 28 and 55 PI. However, plasma thyroid hormones were reduced by infection. On day 28 PI, the average plasma concentrations of T(3) and T(4) were reduced in infected calves (I and I(GH)) 36.4% (P<0.01) and 29.4% (P<0.05), respectively, compared to pair-fed calves (PF and PF(GH)). On day 55 PI, plasma T(3) still remained lower (23.7%, P<0.01 versus PF) in infected calves while plasma T(4) returned to control values. The data suggest that parasitic infection in growing calves inhibits both thyroidal secretion and extrathyroidal T(4) to T(3) conversion during the APR. After recovery from the APR, thyroidal secretion returns to normal but basal and bGH-stimulated generation of T(3) in liver remains impaired.
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Affiliation(s)
- Stanislaw Kahl
- Growth Biology Laboratory, US Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Building 200, Room 211E, Beltsville, MD 20705, USA.
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Capuco AV, Wood DL, Elsasser TH, Kahl S, Erdman RA, Van Tassell CP, Lefcourt A, Piperova LS. Effect of somatotropin on thyroid hormones and cytokines in lactating dairy cows during ad libitum and restricted feed intake. J Dairy Sci 2001; 84:2430-9. [PMID: 11768084 DOI: 10.3168/jds.s0022-0302(01)74693-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Twelve Holsteins in first lactation were used to investigate the relationship between energy balance and effects of bovine somatotropin (bST) on thyroid hormone metabolism and cytokine concentrations in serum. Six cows were fed for ad libitum intake and six cows were feed restricted to induce negative energy balance during two treatment periods of 6 d. During treatment periods, cows were administered vehicle or 40 mg of bST/d according to a crossover design. Between treatment periods was a 15-d recovery period, during which all cows were fed ad libitum. Cows that were fed ad libitum remained in positive energy balance during control and bST treatments, whereas cows that were fed for restricted intake were in negative energy balance during control and bST treatment periods. In both dietary groups, bST decreased energy balance. Milk production and the fat percentage of milk increased during bST treatment in both dietary groups. Fat-corrected milk yield was increased 13% by bST treatment. Serum concentrations of IGF-I did not differ between dietary groups but were greater during bST than control periods. Serum thyroxine concentration was decreased by bST treatment. Serum triiodothyronine and reverse-triiodothyronine were not altered by hormone treatment, but circulating concentrations of thyroid hormones were apparently reduced by dietary restriction. Neither hepatic nor mammary thyroxine 5'-deiodinase was affected by bST treatment. Plasma concentration of tumor necrosis factor-alpha, a potential regulator of thyroxine 5'-deiodinase, was not affected by bST treatment. Short-term treatment with bST did not influence thyroid hormone metabolism in lactating cows in positive or negative energy balance.
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Affiliation(s)
- A V Capuco
- Gene Evaluation and Mapping Laboratory, USDA-ARS, Beltsville, MD 20705, USA.
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Abstract
Thyroid status is compromised in a variety of acute and chronic infections and toxin-mediated disease states. Conversion of thyroxine (T4) into the metabolically active hormone, triiodothyronine (T3), is catalyzed by 5'-deiodinase (5'D). Our objective was to determine the effect of endotoxin (LPS) challenge with and without L-arginine (Arg) infusion on hepatic activity of 5'D and plasma concentrations of T4 and T3. In a 2 x 2 factorial, beef heifers (275-310 kg b.wt.) were fed low (8% CP; 6.5 kg/d) or high (14% CP; 7.2 kg/d) isocaloric protein diets (1.96 Mcal/kg DM) for 10 d before LPS challenge. L-Arginine in saline (0.5 g/kg b.wt.) or saline alone was infused i.v. throughout an 8 hr period starting 2 hr before bolus LPS injection (Escherichia coli, 055: B5; 0.2 microg/kg; i.v.). Blood samples were collected at -2, 0, 3, 6, 12, and 24 hr relative to LPS injection. Liver samples were obtained 20 hr before, and then 6 and 24 hr after LPS challenge using a biopsy needle. Plasma T4 and T3 concentrations were not affected by dietary CP or Arg. Compared with levels at 0 hr, LPS challenge decreased plasma T4 (P < 0.01) and T3 (P < 0.001), respectively, 8.4% and 28.9% at 6 hr and 19.7% and 31.3% at 24 hr. Consistent with these changes, the T3:T4 ratio was lower than that at 0 hr (P < 0.001) 22.0% at 6 hr and 13.5% at 24 hr. Hepatic 5'D activities 20 hr before LPS injection were 2.80 +/- 0.11 nmol I- x hr(-1) x mg protein(-1) and decreased 24 hr after LPS, respectively, 45.4% (P < 0.01) and 17.6% (P < 0.05) in saline- and Arg-infused heifers. The results indicate that mild LPS challenge in cattle inhibits hepatic generation of T3 and decreases plasma concentrations of thyroid hormones. The data also suggest that the impact of LPS on 5'D activity in liver can be altered by Arg supplementation.
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Affiliation(s)
- S Kahl
- Growth Biology Laboratory, US Department of Agriculture, Agricultural Research Service, Livestock and Poultry Sciences Institute, Beltsville, MD 20705, USA.
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Slebodziński AB, Brzezińska-Slebodzińska E, Styczyńska E, Szejnoga M. Presence of thyroxine deiodinases in mammary gland: possible modulation of the enzyme-deiodinating activity by somatotropin. Domest Anim Endocrinol 1999; 17:161-9. [PMID: 10527119 DOI: 10.1016/s0739-7240(99)00033-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Thyroid hormones (TH) and somatotropin (ST) play critical role in lactation. One explanation of their multiple physiological actions is based on the functional interrelationships among ST, TH, and thyroxin deiodinase (5'D). This enzyme is present in the mammary tissue, milk cellular components, and whole milk and is responsible for intramammary production of triiodothyronine (T3). In rats in which the 5'D isozymes in the mammary gland and in the liver are similarly of type I (5'D-I), an enhancement of mammary 5'D-I causes a reduction of hepatic 5'D-I activities. This opposite rearrangement in the mammary and hepatic deiodinating activities is thought to be a factor of a homeorhetic response characterized by an increased and compartmentalized energy expenditure of the mammary gland. In the cow, the mammary 5'D is the type II (5'D-II) deiodinase. The 5'D-II, owing to its high catalytic efficiency, secures T3 production, making tissues relatively independent from the circulatory levels of TH and from variations in the hepatic 5'D-I activity. No significant alterations of 5'D-II isozymes were found during a low T3 syndrome. Location of tissue deiodinases in the cow, the 5'D-II in the mammary gland, and the 5'D-I in the liver make it so that T3 production in these two tissues can be dissociated in time to secure better local requirement for T3 supporting lactation. To date, attempts to evidence that the alterations in iodothyronines blood levels and in tissues' 5'Ds activity during lactation are due to ST action have not received clear experimental support in either cows or rats.
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Affiliation(s)
- A B Slebodziński
- Institute of Animal Reproduction and Food Research, Polish Academic Science, Department of Developmental and Experimental Endocrinology, Poznan.
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Romo GA, Elsasser TH, Kahl S, Erdman RA, Casper DP. Dietary fatty acids modulate hormone responses in lactating cows: mechanistic role for 5'-deiodinase activity in tissue. Domest Anim Endocrinol 1997; 14:409-20. [PMID: 9437577 DOI: 10.1016/s0739-7240(97)00046-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Supplemental dietary fat provides excess fatty acids (FA), which can alter circulating concentrations of several hormones. To test the effects of fatty acid isomer type and possible sites of regulation, we abomasally infused fat mixtures high in cis-C18:1 FA (iCIS), high in trans-C18:1 FA (iTRS) or no infusion (NI) and performed intravenous arginine (ARG) and intramuscular thyrotropin-releasing hormone (TRH) challenges. The experimental design was a replicated 3 x 3 Latin square. Challenges were conducted on Days 10 (ARG) and 12 (TRH) after initiation of fat infusion on each of three 4-wk experimental periods. Plasma concentrations of IGF-I were lower (P < 0.01) when cows received iCIS or iTRS compared with NI. Plasma insulin concentrations increased with ARG but responses were not affected by FA. Plasma growth hormone (GH) was unchanged after ARG. Peak plasma GH and thyroid-stimulating hormone (TSH) responses to TRH were blunted (P < 0.05 and P < 0.1, respectively), whereas thyroxine (T4) and triiodothyronine (T3) responses were augmented post-TRH (P < 0.01) when cows received either FA isomer. Prolactin responses to TRH were not different between infusion treatments, although basal plasma concentrations before TRH were higher in cows infused with iTRS (P < 0.05). To focus on fat regulation of the thyroid axis, we tested directly in vitro the ability of fatty acids dissolved with sodium taurocholate to affect Type-I 5'-deiodinase (5'D) activity in bovine liver homogenates. Homogenate 5'D was not affected by C2:0-C10:0 fatty acids, but decreased linearly (P < 0.01) with increasing concentrations of C12:0-C16:0 and C18:1 isomers. Cis C18:1 decreased 5'D more than the trans-isomer (P < 0.01), but the difference was only apparent at concentrations greater than 0.25 mM. The data suggest that various aspects of pituitary hormone regulation are differentially affected by FA composition. Fatty acid infusion may accentuate end organ responses in the thyroid axis and decrease IGF-I in the somatotropic axis. The data also suggest that FA isomer may alter patterns of extrathyroidal generation of thyroid hormones via direct influences on 5'D.
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Affiliation(s)
- G A Romo
- Department of Animal Sciences, University of Maryland, College Park 20742, USA
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Rumsey TS, Elsasser TH, Kahl S. Roasted soybeans and an estrogenic growth promoter affect the thyroid status of beef steers. J Nutr 1997; 127:352-8. [PMID: 9039839 DOI: 10.1093/jn/127.2.352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
We investigated the interactive effects of a roasted soybean (RSB)-supplemented diet and an estrogen ear implant [Synovex-S (SYN), 20 mg estradiol benzoate + 200 mg progesterone] in young beef steers on measures of thyroid status before and after challenge injections of thyrotropin-releasing hormone (TRH) + growth hormone-releasing hormone (GHRH). Twenty steers (body weight 255 +/- 5 kg) were assigned to the following treatments: 1) no SYN and a soybean meal-supplemented diet, 2) no SYN and a RSB-supplemented diet, 3) plus SYN and soybean meal, and 4) plus SYN and RSB. Steers were individually fed 1.13 MJ metabolizable energy/kg metabolic body wt daily of an 18% protein diet. After a 5-wk growth period, all steers were challenged (intravenous injection) over a 3-wk period with three dose levels of a combination of TRH + GHRH (0.1 + 0.01, 1.0 + 0.1 and 2.5 + 0.25 microg/kg body wt). There were no dose by SYN or RSB interactions. Across dose levels, values for baseline plasma thyroid-stimulating hormone (TSH) were 0.37, 0.35, 0.61 and 0.33 microg/L for treatments 1, 2, 3 and 4, respectively (SYN, P < 0.07; RSB, P < 0.01; SYN x RSB, P < 0.03; SEM 0.06). Net areas under the response curve for TSH were 66.4, 51.3, 91.4 and 64.4 (microg/L) x min, respectively (RSB, P < 0.08; SEM 12.0). Similar treatment effects and/or numerical differences after challenge were noted for thyroxine (T4) but not triiodothyronine (T3). Baseline (2.22 vs. 2.00 microg/L, P < 0.02) and peak (3.07 vs. 2.03 microg/L, P < 0.03) T3 concentrations were less for steers fed RSB than for steers fed soybean meal. This study indicates that in young growing beef steers, SYN increases TSH release from the adenohypophysis and that the primary effect of RSB is reduced plasma T3, possibly through an effect on peripheral T4 deiodination.
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Affiliation(s)
- T S Rumsey
- Livestock and Poultry Sciences Institute, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705-2350, USA
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Binelli M, Vanderkooi WK, Chapin LT, Vandehaar MJ, Turner JD, Moseley WM, Tucker HA. Comparison of growth hormone-releasing factor and somatotropin: body growth and lactation of primiparous cows. J Dairy Sci 1995; 78:2129-39. [PMID: 8598397 DOI: 10.3168/jds.s0022-0302(95)76840-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Growth hormone-releasing factor is the main endogenous stimulator of somatotropin secretion. Our objective was to compare the effects of recombinant growth hormone-releasing factor and recombinant bST on somatotropin secretion, mammary function, and body composition of lactating, primiparous dairy cows. Cows (118 d of lactation) served as uninfused controls or were infused for 63 d with 12 mg/d of releasing factor or with 29 mg/d of bST. These doses elevated somatotropin in serum to concentrations of similar magnitude. The releasing factor and bST each similarly increased milk yield, yield of milk components, weight of most organs, mobilization of adipose tissue, accretion of lean tissue in the carcass, and metabolic activity (RNA) of mammary tissue. Relative to controls, neither releasing factor nor bST significantly affected cell numbers (DNA) in mammary glands or concentrations of plasmin in milk. None of the variables measured provided evidence for galactopoietic effects of releasing factor independent of somatotropin.
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Affiliation(s)
- M Binelli
- Department of Animal Science, Michigan State University, East Lansing 48824, USA
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Liesman JS, McNamara JP, Capuco AV, Binelli M, Vanderkooi WK, Emery RS, Tucker HA, Moseley WM. Comparison of growth hormone-releasing factor and somatotropin: lipid and glucose metabolism in dairy cows. J Dairy Sci 1995; 78:2159-66. [PMID: 8598400 DOI: 10.3168/jds.s0022-0302(95)76843-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Lactating, primiparous Holstein cows were continuously infused for 63 d with either recombinant growth hormone-releasing factor or recombinant bST or were not infused (control). The releasing factor and bST treatments reduced fat synthesis from acetate and lipoprotein lipase activity in omental adipose tissue. Also, both treatments increased hormone-sensitive lipase activity per gram of adipose tissue and reduced fatty acid esterification per milligram of protein in adipose tissue. Protein concentration in adipose tissue with both treatments was greater than that of the control, although the protein concentration was less in adipose tissue from cows treated with the releasing factor than from those treated with bST. In mammary tissue, releasing factor increased fat synthesis from acetate more than did bST treatment, but percentages of fat or short-chain fatty acids in milk were not different between treatments, nor were differences significant between treatments and control for fatty acid esterification or lipoprotein lipase activity in mammary tissue or gluconeogenesis and fatty acid esterification in liver. We conclude that protein concentration was lower in omental adipose tissue of cows treated with releasing factor than that in tissue of cows treated with bST, although both treatments similarly suppressed synthesis of fat from acetate and activity of lipoprotein lipase.
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Affiliation(s)
- J S Liesman
- Department of Animal Science, Michigan State University, East Lansing 48824, USA
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Vanderkooi WK, Vandehaar MJ, Sharma BK, Binelli M, Tucker HA, Akers RM, Moseley WM. Comparison of growth hormone-releasing factor and somatotropin: the somatotropic axis in lactating primiparous cows. J Dairy Sci 1995; 78:2140-9. [PMID: 8598398 DOI: 10.3168/jds.s0022-0302(95)76841-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Our objective was to compare the effects of recombinant bovine growth hormone-releasing factor and recombinant bST on the somatotropic cascade in lactating dairy cows. Primiparous cows were killed after 63 d of continuous daily infusion with 12 mg of releasing factor or 29 mg of bST or no infusion (controls). Both hormone infusions similarly increased mean concentration of somatotropin in serum, but pulsatility of somatotropin in serum was greater for cows given releasing factor. Both hormone infusions increased the amounts of IGF-I in serum, IGF-I mRNA in liver, and IGF-binding protein-3 in serum and decreased IGF binding protein-2 in serum, but these effects were less for cows given releasing factor than for those given bST. Both infusions decreased the number of free binding sites for IGF-I in mammary tissue. In liver, treatment did not alter the abundance of mRNA for the somatotropin receptor or the number of free binding sites for somatotropin. Results suggest that endogenous somatotropin is less effective as an IGF-I secretagogue than is exogenous bST infused continuously, yet the releasing factor and bST increased milk yield similarly. We conclude that growth hormone-releasing factor stimulates milk synthesis mostly through the same mechanisms as bST, but that serum IGF-I alone is not a good indicator of the galactopoietic potency of the two hormones.
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Affiliation(s)
- W K Vanderkooi
- Department of Animal Science, Michigan State University, East Lansing 48824, USA
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