Serum Thyroxine Concentrations Research Articles

Changes in Erythrocytes in 88 Hyperthyroid Cats.

There is only a limited number of studies that show alterations in erythrocytes in feline hyperthyroidism. Discrepancies between the findings of these studies may be caused by the presence of concurrent diseases and the use of various haematological analysers. This study analysed changes in red blood cells (RBCs) in 88 hyperthyroid cats without concurrent diseases, to identify associations between observed changes and to assess the influence of serum thyroxine (T4) concentration, cat age, and sex, on RBC changes. Among the eighty-eight hyperthyroid cats, erythrocytosis was observed in twelve, anaemia in four, macrocytosis in two, and microcytosis in three. Three of the four cases of anaemia probably resulted from concurrent unrecognised disease. Interestingly, all cases of microcytosis were recognized in cats that had erythrocytosis. This study identified a moderate negative correlation between RBC count and mean corpuscular volume (MCV; r = -0.57, p < 0.001). Concluding, it appears that erythrocytosis may be a response to the development of microcytosis. The correlation between RBC count and MCV in hyperthyroid cats may result from the increased action of hepcidin and erythropoietin coupled with the decreased action of thyroid-stimulating hormone (TSH).

Suppression of Hippocampal Neurogenesis and Oligodendrocyte Maturation Similar to Developmental Hypothyroidism by Maternal Exposure of Rats to Ammonium Perchlorate, a Gunpowder Raw Material and Known Environmental Contaminant.

The environmental contaminant perchlorate raises concern for hypothyroidism-related brain disorders in children. This study investigated the effects of developmental perchlorate exposure on hippocampal neurogenesis and oligodendrocyte (OL) development. Pregnant Sprague-Dawley rats were administered with ammonium perchlorate (AP) in drinking water at concentrations of 0 (control), 300, and 1000 ppm from gestation day 6 until weaning [postnatal day (PND) 21]. On PND 21, offspring displayed decreased serum triiodothyronine and thyroxine concentrations at 1000 ppm and thyroid follicular epithelial cell hyperplasia at ≥300 ppm (accompanying increased proliferation activity at 1000 ppm). Hippocampal neurogenesis indicated suppressed proliferation of neurogenic cells at ≥300 ppm, causing decreases in type-1 neural stem cells (NSCs) and type-2a neural progenitor cells. In addition, an increase of SST+ GABAergic interneurons and decreasing trend for ARC+ granule cells were observed at 1000 ppm. CNPase+ mature OLs were decreased in number in the dentate gyrus hilus at ≥300 ppm. At PND 77, thyroid changes had disappeared; however, the decrease of type-1 NSCs and increase of SST+ interneurons persisted, CCK+ interneurons were increased, and white matter tissue area was decreased at 1000 ppm. Obtained results suggest an induction of hypothyroidism causing suppressed hippocampal neurogenesis (targeting early neurogenic processes and decreased synaptic plasticity of granule cells involving ameliorative interneuron responses) and suppressed OL maturation during the weaning period. In adulthood, suppression of neurogenesis continued, and white matter hypoplasia was evident. Observed brain changes were similar to those caused by developmental hypothyroidism, suggesting that AP-induced developmental neurotoxicity was due to hypothyroidism.

Serum chemistry, thyroxine concentration, and blood cell morphology of wild, young Blackchin Guitarfish Glaucostegus cemiculus sampled on the eastern Mediterranean coastline.

The Blackchin Guitarfish Glaucostegus cemiculus is endemic to the Mediterranean Sea and is critically endangered, but relevant routine laboratory data are unavailable. Our objectives were to determine the packed cell volume (PCV), comprehensive serum chemistry analytes, and serum total thyroxine (sTT4) concentration; compare serum albumin and serum globulin concentrations as measured by two different methods; and describe the blood cell morphology of healthy, free-ranging Blackchin Guitarfish. Wild Blackchin Guitarfish were captured using a seine net. Blood samples for serum chemistry and hematological analyses were obtained and measured using routine laboratory methods. The fish were tagged and released. This study included 43 Blackchin Guitarfish (17 males and 26 females) that were younger than 6 months as estimated based on total length and body weight. The median PCV (n = 23) was 22% (minimum-maximum [min-max] = 15-25%). Median sTT4 (n = 10) measured by chemiluminescence immunoassay was 7.86 nmol/L (min-max = 7.52-9.57 nmol/L). The study included a comprehensive, 25-analyte serum chemistry analysis (e.g., serum iron and unbound and total iron-binding capacity) and a morphological description of all blood cells. Serum electrophoresis (SEP; n = 13) yielded a consistent serum albumin-migrating protein fraction and four globulin fractions. Serum electrophoretograms corroborating these results are presented. In Blackchin Guitarfish, the serum albumin-migrating fraction measured by SEP combined with serum total protein concentration yields a much higher albumin concentration compared to that measured by bromocresol green spectrophotometry. The true identity of this albumin-migrating fraction remains to be identified. The analytes' calculated 2.5-97.5% interpercentile intervals should be considered as reference intervals applying to Blackchin Guitarfish of similar age but should be applied cautiously to adult fish.

Effects of GH L127V and TG5 C422T polymorphisms on the hormonal profile, slaughter traits, and meat quality of Hereford bulls.

The creation of objective methods for the evaluation and improvement of quantitative and qualitative indicators of meat productivity in farm animals should be based on a comprehensive analysis of the genetic, physiological, and biochemical parameters of the animal. This study aimed to investigate the effects of growth hormone (GH) and thyroglobulin (TG5) gene polymorphisms on the hormonal status, slaughter traits, and chemical, amino acid, and fatty acid composition of meat in Hereford bulls. Hereford bulls (n = 9) were reared under the same feeding and housing conditions until the age of 21 months, after which they were slaughtered. Polymerase chain reaction-restriction fragment length polymorphism was performed for genotyping GH L127V and TG5 C422T polymorphisms. The experimental animals were evaluated to determine slaughter traits (including pre-slaughter weight, carcass, and internal fat weight and yield), chemical, fatty acid, and amino acid composition of ground beef, and hormonal status using serum concentrations of GH, triiodothyronine, and thyroxine. Animals with the valine homozygous (VV) genotype of GH had the maximum serum GH level of 9.33 mIU/mL (p = 0.10) higher than leucine homozygous (LL) genotype carriers. Individuals with the LL genotype outperformed V-allele carriers in serum thyroxine (T4) concentration by 21.3-30.5 nmol/L (16.15%-24.86%; p < 0.01-0.05). Genetic differentiation induced by TG5 C422T polymorphism was determined to a lesser extent by the hormonal status of the Hereford animals. The V-allele was associated with increased carcass weight, with VV homozygotes significantly outperforming LL individuals by 45.0 kg (13.61%; p < 0.05). The T allele at the TG5 gene polymorphism was associated with more intense lipogenesis and less protein synthesis in muscle tissue and these effects were enhanced in the homozygous state. Young animals with the TT variant of the TG5 gene exhibited a significantly superior polyunsaturated fatty acid/saturated fatty acid ratio of 0.012 units (p < 0.01). Carriers of the LL genotype were characterized by minimum amino acid content in muscle tissue. Heterozygous bulls exceeded LL homozygotes in the sum of essential amino acids by 3.09% (p = 0.10) and non-essential amino acids by 1.9% (p < 0.05). The development of breeding programs for the Hereford breed should be carried out considering genetic features that determine the formation of economic traits in animals. Analysis of polymorphisms in the TG5 gene is a promising method for the early diagnosis of the fatty acid composition of beef. Identification of polymorphisms in the GH gene allows the prediction of higher productivity potential and amino acid composition of meat. The different effects of the GH and TG5 genes on the development of various economic traits allowed us to determine further vectors for scientific research on their complex associations in Hereford cattle, which will be useful for planning effective breeding schemes.

The time course of lactate and endocrine changes in dogs suffering from dog bite wounds.

The stress response after acute trauma in humans and animals has been well-recognised in the literature. However, data on temporal changes in endocrine parameters after acute trauma in previously healthy dogs are scant. To longitudinally track endocrine variables and lactate concentrations in dogs with canine bite wounds. Prospective study involving 20 dogs hospitalised after being bitten by another dog. Serum cortisol, thyroxine (total T4), thyrotropin (TSH), and lactate concentrations were measured on admission and every 8 hours after the recorded bite incident, for a 72-hour period. Median cortisol concentration was markedly elevated on admission (314.6 nmol/L; IQR 229.3-369.6) but returned to within the reference interval by 16 hours post-bite (99.5 nmol/L; IQR 48.7-225.4) and reached a nadir at 48 hours post-bite (38.5 nmol/L; IQR 32.1-115.9). Median total T4 concentration was within the reference interval on admission (20.6 nmol/L; IQR 12.7-27.9) but decreased below the reference interval by 8 hours (11.0 nmol/L; IQR 5.0-14.1) and reached a nadir 16 hours postbite (7.0 nmol/L; IQR 2.9-19.7), before gradually increasing after 64 hours to reach the reference range by 72 hours. The median TSH concentrations remained within the reference interval throughout the study period. Median lactate concentration was mildly elevated on admission (3.0 mmol/L; IQR 2.0-3.9). This study produced novel data on the temporal relationships of the hypothalamic-pituitary-adrenal and hypothalamicpituitary- thyroidal axes alterations after an acute traumatic insult in dogs.

138 Growth performance and physiological response of nursery pigs fed a high canola meal diet with acidifiers

Abstract This study investigated the impact of feed additives aimed at reducing gut pH on the growth performance and physiological responses of nursery pigs when fed a high canola meal (CM) diet. A total of 315 nursery pigs, 6.0 ± 1.2 kg body weight (BW), were allotted to one of five dietary treatments with 9 replicates (7 pigs/pen) in a randomized complete block design. Dietary treatments were PC: corn-soybean meal-based diet with 20% CM, NC: corn-soybean meal-based diet with 40% CM; NC+A: NC diet with acidifier at 1,500 ppm, NC+B: NC diet with encapsulated butyrate at 500 ppm, and NC+A+B: NC diet with acidifier and encapsulated butyrate. All diets were formulated to meet or exceed the nutrient requirements of NRC (2012). All pigs received a common Phase 1 nursery diet during week 1 following weaning. Experimental diets were provided in Phase 2 (wk 2 and 3) and Phase 3 (wk 4 to 6). Individual pig BW and pen feed consumption were measured for each phase to calculate growth performance. At the conclusion of each phase, blood samples were collected from one pig per pen for analysis of serum triiodothyronine (T3) and thyroxine (T4) concentrations. The selected pig was euthanized within 24 h, and its organ weights and pH of digesta were measured. The results were analyzed using MIXED procedure in SAS with the pen as an experimental unit. There was no difference in BW and average daily gain throughout the overall period. However, PC treatment exhibited greater (P &amp;lt; 0.05) average daily feed intake in phase 3 by 18.2% and overall period by 13.4% compared with NC treatment and no difference with NC+A+B treatment. The NC+A and NC+A+B treatments tended to improve (P ≤ 0.10) gain to feed ratio in phase 3 by 17.9% and overall period by 16.1% compared with PC treatment, respectively. At the end of phase 3, the PC treatment tended (P &amp;lt; 0.10) to have greater serum T4 concentrations compared with NC and NC+A treatments (3.2 vs 2.5 and 2.4 ug/dL, respectively), whereas there was no difference between PC and NC+A+B treatments. In phase 3, the thyroid gland weight for PC treatment was less (P &amp;lt; 0.05) than for NC treatment (0.156 vs 0.202 g/kg), whereas there was no difference among PC, NC+B, and NC+A+B treatments. In phase 3, dietary encapsulated butyrate decreased (P &amp;lt; 0.05) the pH of jejunal digesta compared with PC treatment (6.28 vs 7.01), and dietary encapsulated butyrate treatments (NC+B and NC+A+B) tended to decrease (P &amp;lt; 0.10) the pH of hind-colonic digesta compared with the pH of PC treatment by 6.2% and 7.2%. In conclusion, dietary encapsulated butyrate in combination with acidifier may alleviate thyroid dysfunction that is anti-nutritional effect of high canola meal diets.

The effects of pioglitazone and rosiglitazone on liver function in hypothyroid rats.

This study aimed to investigate the antioxidant effect of rosiglitazone (ROG) and pioglitazone (POG) on oxidative damage and dysfunction of hepatic tissue in hypothyroid rats. The male rats were classified into six groups: (1) Control; (2) Hypothyroid, (3) Hypothyroid-POG 10, (4) Hypothyroid-POG 20, (5) Hypothyroid-ROG 2, and (6) Hypothyroid-ROG 4. To induction hypothyroidism in rats, propylthiouracil (PTU) (0.05 %w/v) was added to drinking water. In groups 2-6, besides PTU, the rats were also intraperitoneal administrated with 10 or 20 mg/kg POG or 2 or 4 mg/kg ROG for six weeks. Finally, after deep anesthesia, the blood was collected to measure the serum biochemical markers and hepatic tissue was separated for biochemical oxidative stress markers. Administration of PTU significantly reduced serum thyroxin concentration, total thiol levels, activity of superoxide dismutase (SOD) and catalase (CAT) enzymes, and increased serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (Alk-P) and malondialdehyde (MDA) in the liver. Additionally, our results showed that prescription of POG or ROG for six weeks to hypothyroid rats resulted in an improvement in liver dysfunction (decrease in serum levels of AST, ALT, and ALK-P) through reducing oxidative damage in hepatic tissue (increase in CAT, SOD, or total thiols and decrease in MDA levels). The findings of the present study presented that the IP administration of POG and ROG for six weeks improves liver dysfunction induced by hypothyroidism in juvenile rats by reducing oxidative damage.

Total thyroxine and thyroid-stimulating hormone responses of healthy cats to different doses of thyrotropin-releasing hormone.

Thyrotropin-releasing hormone (TRH) stimulation can be used as a test of thyroid function and pituitary thyrotropin (thyroid-stimulating hormone, TSH) reserve, but optimal stimulation testing protocols in cats are unreported. We randomly divided 6 healthy young adult cats into 3 groups of 2 and administered 3 different intravenous doses of TRH (0.01, 0.05, 0.1 mg/kg) at weekly intervals in our crossover study. Serum TSH and thyroxine (T4) concentrations were measured using chemiluminescent immunoassay before, and at 30 and 60 min after, TRH administration. All cats were monitored for 4 h post-TRH administration for side effects. All 3 TRH doses induced significant TSH (0.01 mg/kg, p = 0.001; 0.05 mg/kg, p = 0.002; 0.1 mg/kg, p = 0.006) and total T4 (0.01 mg/kg, p = 0.008; 0.05 mg/kg, p = 0.006; 0.1 mg/kg, p = 0.001) responses. Lower TRH doses (0.01 and 0.05 mg/kg) caused fewer side effects (1 of 6 cats) than did the highest dose (3 of 6 cats), and may be safer in cats than the previously reported higher dose (0.1 mg/kg) of TRH. Our results do not support the use of maropitant to prevent side effects of a TRH stimulation test in cats.

Urine concentrating ability in cats with hyperthyroidism: Influence of radioiodine treatment, masked azotemia, and iatrogenic hypothyroidism.

Hyperthyroid cats often have urine specific gravity (USG) values <1.035. It remains unclear how USG changes after treatment, if USG can be used to predict azotemia after treatment, or how iatrogenic hypothyroidism influences USG values. To determine the proportion of hyperthyroid cats with USG <1.035 vs ≥1.035; if USG changes after treatment; and whether USG <1.035 correlated with unmasking of azotemia or hypothyroidism. Six hundred fifty-five hyperthyroid cats treated with radioiodine; 190 clinically normal cats. Prospective, before-and-after study. Hyperthyroid cats had serum thyroxine, thyroid-stimulating hormone, and creatinine concentrations, and USG measured before and 6 months after successful treatment with radioiodine. Of untreated hyperthyroid cats, USG was ≥1.035 in 346 (52.8%) and <1.035 in 309 (47.2%). After treatment, 279/346 (80.6%) maintained USG ≥1.035, whereas 67/346 (19.4%) became <1.035; 272/309 (88%) maintained USG <1.035, whereas 37/309 (12%) became ≥1.035. Only 22/346 (6.4%) with USG ≥1.035 developed azotemia after treatment, compared with 136/309 (44%) with <1.035 (P < .001). Of cats remaining nonazotemic, 38% had USG <1.035, compared with 20% of normal cats (P < .001). The 137 cats with iatrogenic hypothyroidism had lower USG after treatment than did 508 euthyroid cats (1.024 vs 1.035), but USGs did not change after levothyroxine supplementation. USG <1.035 had high sensitivity (86.1%) but moderate specificity (65.2%) in predicting azotemia after treatment. Hyperthyroidism appears not to affect USG in cats. However, cats with evidence of sub-optimal concentrating ability before radioiodine treatment (USG < 1.035) are more likely to develop azotemia and unmask previously occult chronic kidney disease. Iatrogenic hypothyroidism itself did not appear to affect USG values.

Plasma metabolic profiling reveals that chromium yeast alleviates the negative effects of heat stress in mid-lactation dairy cows.

Chromium yeast (CY) supplementation has the potential to alleviate the negative effects of heat stress in dairy cows, but the mechanism remains elusive. We aimed to identify the metabolic mechanisms whereby CY supplementation alleviates the negative effects of heat stress in mid-lactation dairy cows. Twelve Holstein dairy cows with similar milk yield (24.6±1.5kg/d), parity (2 or 3) and days in milk (125±8d) were fed the same basal diet containing 0.09mg of Cr/kg DM. They were allocated randomly to 2 groups: a control group (CON, without CY supplementation) and a CY group (CY, administered 0.36mg Cr/kg DM). The experiment was performed over 8 weeks during a hot summer, in which the mean temperature-humidity index was 79.0±3.13 (>72), indicating that the dairy cows were exposed to heat stress. Chromium yeast supplementation reduced rectal temperature (P=0.032), and increased the lactation performance by increasing the yield of milk (+2.6kg/d), protein, lactose and total solid, and protein and lactose percentages in the milk of the heat-stressed dairy cows (P<0.05). Supplementation with CY increased the serum glucose and thyroxine concentrations, but reduced the urea nitrogen, insulin, and triiodothyronine concentrations on d 56 (P<0.05). Furthermore, plasma metabolomic analysis was performed using liquid chromatography tandem-mass spectrometry, which identified 385 metabolites in the two groups. Subsequently, 16 significantly different metabolites in the plasma, were significantly higher in the CY group (variable importance for the projection >1.0, P<0.05), and found to be involved in 6 Kyoto Encyclopedia of Genes and Genomes pathways, including those involved in nicotinate and nicotinamide metabolism. Specifically, plasma concentration of nicotinamide was higher after CY supplementation, which might also contribute to the reduction of rectal temperature, the regulation of glucose homeostasis, and an improvement in the lactation performance of heat-stressed dairy cows. In conclusion, CY supplementation reduces rectal temperature, influences metabolism by reducing serum insulin concentration and increasing serum glucose and plasma nicotinamide concentrations, and finally increases lactation performance of heat-stressed dairy cows.

Effects of varying doses of conjugated estrogen on body weight, hormonal and histological alterations of reproductive organs in adult swiss albino female mice

Estrogens are a group of hormones that have diverse effects on both reproductive and non-reproductive organs. Conjugated estrogens are medicine that contains a mixture of estrogen hormones. The study was conducted to observe the effects of varying doses of conjugated estrogen on body weight, hormonal and histological alterations of reproductive organs in adult swiss albino female mice. In this study, 60 female swiss albino mice (Mus musculus) aged 28–30 days with an average body weight of 28.2 ± 1 g were used. At first, the mice were randomly divided into 4 groups each containing 15 mice. Group A was served as vehicle control and fed on standard mice pellet and fresh drinking water. While, groups B, C and D were administered with conjugated estrogen orally at the daily dose rate of 125 μg, 250 μg and 500 μg/kg body weight respectively with 1 mL sesame oil as a vehicle by mixing with feed. The experiment was carried out for 90 days. After humanly euthanized, blood was collected and serum was prepared and organs were collected for histopathology. The results revealed that higher doses of conjugated estrogen resulted in weight loss in premenopausal female mice compared to lower doses. Serum estrogen and thyroxine concentration was increased significantly following the doses of conjugated estrogen. Ovarian histotexture showed congested blood vessels and cystic space with degeneration of follicles and corpus luteum. Uterine lesions included massive macrophage infiltration in endometrium and hyperplasia of glandular epithelium at a lower dose; hyperplasia and hypertrophy of glandular epithelium (pleomorphism) with normal macrophage infiltration in endometrium at a higher dose. Therefore, it can be concluded that oral conjugated estrogen therapy at high dose has more detrimental impacts on body weight and reproductive function compared to lower dose in female adult mice.

Rat Serum Osteocalcin Concentration Is Decreased by Restriction of Energy Intake

We studied the effects of energy restriction on serum osteocalcin concentration and bone formation rate in rats. The experiment was designed to achieve energy restriction by reducing the carbohydrate intake while providing identical quantities of protein, fat, vitamins and minerals. Energy intakes of three groups of post-weaning male rats were restricted by 20, 40 and 60% for 4 wk. Serum calclum, phosphorus, transthyretin, triiodothyronine (T3), thyroxine (T4), 1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol and immunoreactive parathyroid hormone (iPTH) concentrations were determined. Energy restriction (20, 40 and 60%) produced a significant and gradual drop of serum osteocalcin concentrations, although the serum concentrations of its key regulators, i.e., 1,25-dihydroxycholecalciferol and iPTH, were not significantly affected. On the contrary, serum concentrations of calcium, phosphorus, transthyretin, T3 and T4 were significantly lower in the energy-restricted groups. However, our results do not support their implication in the regulation of serum osteocalcin synthesis by energy intake. Serum osteocalcin concentration was positively correlated with bone mineral apposition (r = 0.50, P < 0.05) and bone mineralization (r = 0.50, P < 0.05) rates suggesting that its decrease resulted from a reduction of bone formation, and not from abnormal mineralization, because osteoid seam thickness was not modified. Energy intake seems to be an important determinant of serum osteocalcin concentration and bone formation; however, the exact mechanism underlying this regulation remains to be determined.

Thyroid hormone dynamics of Tharparkar and Sahiwal cattle during induced heat stress

Thyroid hormones and Cortisol level are the essential biomarkers in the assessment of stress condition. This study was done to estimate the metabolic hormonal profile of Tharparkar and Sahiwal during heat stress condition. The experiment was conducted on two groups consisting of Tharparkar and Sahiwal animals (5 in each group) and the experimental period comprised a 7-day acclimatization period, a heat exposure period of 21days at control (25°C), moderate (35°C) and severe (42°C) heat stress within a 9-10-day recovery period between each exposure. The hormonal concentrations of T3, T4 and cortisol were determined in serum. The serum concentration of Thyroxine (T4) and tri-iodothyronine (T3) decreases whereas cortisol level increases in both the breeds when subjected to heat stress. However, the serum level of T4 was significantly (p < 0.05) more declined in Sahiwal as compared to Tharparkar but there was no significant difference found between the two breeds in serum T3 levels. The cortisol levels were elevated in both breeds during heat stress but significantly (p < 0.05) more elevated in the Sahiwal. Hence, observations of these hormonal profiles suggest a better thermo-adaptability in Tharparkar as compared to Sahiwal.

Serial changes in the concentrations of cortisol and thyroid hormones in Beagle dogs infected with Babesia rossi

An experimental infection using Babesia (B.) rossi was performed in healthy male Beagle dogs to assess the changes in endocrine variables during disease. Two dogs were infected with a low dose (LD) of parasite inoculum (104 parasites) and three dogs were infected with a high dose (HD) (108 parasites). Basal serum cortisol, thyroxine (T4), and thyrotropin (TSH) concentrations were measured every second day. Samples were analyzed using a solid- phase, competitive chemiluminescent enzyme immunoassay (Immulyte® 2000, Siemens). Variables were compared between groups and timepoints using linear mixed models. In both groups, the median cortisol concentration increased, whilst the median T4 concentration decreased after infection, with a return towards baseline concentration post treatment. The highest cortisol and the lowest T4 concentrations were reached at 96 h and 108 h post infection, respectively, in the HD group and slightly later at 108 and 144 h post-infection, respectively, in the LD group. A higher cortisol concentration with a more rapid increase, and a lower T4 concentration with a more rapid decline, were associated with disease severity and a higher dose of parasite inoculum. The TSH concentration remained within the reference interval throughout the study period. This study illustrated the temporal changes in endocrine parameters during experimental B. rossi infection and demonstrated that cortisol and T4 tracked the severity of disease, albeit in opposite directions.

Castration alters the cecal microbiota and inhibits growth in Holstein cattle.

To determine the effects of castration on growth performance, serum hormone levels, cecal microbiota composition, and metabolites in cattle. A total of 18 Holstein bulls and steers were divided into bull and steer groups and randomly assigned to 3 pens (3 cattle per pen, and each cattle were separated by a fence) to determine the average daily gain (ADG), daily dry matter intake (DMI), and feed efficiency (G/F). After the finishing trial, six cattle per group were randomly slaughtered. Serum was collected to measure the hormone concentration, and the cecal content was collected to measure the pH, short-chain fatty acids, and digestive enzyme activities. Metagenome sequencing and untargeted metabolomics were used to investigate the microbiota composition, functional profiles, and differential metabolites of the cecal contents. We found that castration significantly decreased ADG, DMI, and G/F in cattle (P < 0.05). The serum testosterone, thyroxine, growth hormone (P < 0.05), and triiodothyronine (P < 0.01) concentrations significantly decreased in the steer group when compared to those of the bull group. The activities of cellulase, xylanase, pectinase, and β-glucosidase (P < 0.05) significantly decreased in the steer group, whereas the activities of lipase and α-amylase significantly increased. Moreover, castration significantly decreased the relative abundance of Ruminococcaceae_bacterium, Treponema_porcinum, Oscillibacter_sp. (P < 0.05), and Alistipes_senegalensis (P < 0.01), whereas the relative abundance of Phocaeicola_plebeius (P < 0.05) was significantly increased. Also, the relative abundance of Phocaeicola_plebeius was negatively correlated with testosterone levels, and the function of the cecal microbiota was enriched in the GH29 and GH97 families in the steer group. Metabolomic analysis indicated that castration increased the levels of L-valine, L-phenylalanine, L-aspartic acid, L-isoleucine, L-lysine, methionine, L-glutamic acid, and L-leucine, while decreasing the levels of α-ketoglutaric acid through the 2-oxocarboxylic acid metabolism pathway. In addition, α-ketoglutaric acid was negatively correlated with Oscillibacter_sp. (P < 0.01). Overall, castration can inhibit cattle growth by altering the composition of the cecal microbiota. Therefore, this study provides a theoretical and practical basis for improving the growth performance of steers.

Association of recessive c.430G>A (p.(Gly144Arg)) thyroid peroxidase variant with primary congenital hypothyroidism in cats.

BackgroundPrimary congenital hypothyroidism (CH) is a rare endocrine disorder in cats with a largely unknown genetic cause.ObjectivesDescribe the clinical presentation of CH in 11 affected cats and identify the causal genetic variant.AnimalsEleven CH‐cats from 10 unrelated families, 11 CH‐free family members, 21 unrelated CH‐free cats, and 155 unrelated nondiagnosed cats from different breeds.MethodsCase control study of CH‐cats and their siblings (2019‐2021). Diagnosis was based on low to low‐normal serum thyroxine (T4) concentrations, high thyroid‐stimulating hormone (TSH) concentrations and clinical signs compatible with CH. We identified the causal variant using Sanger sequencing, genotyping via PCR‐RFLP and variant interpretation using ACMG/AMP guidelines.ResultsAll CH‐cats (5 weeks‐8 years) had disproportionate dwarfism. A goiter was not palpable in all. Thyroid scintigraphy with radiopertechnetate showed abnormally high uptake by thyroid glands, whereas scintigraphy with radioiodine showed abnormally low uptake, compatible with a defect in iodine organification by thyroid peroxidase (TPO). All cases were homozygous for TPO variant XM_006930524.4:c.430G>A(p.(Gly144Arg)), while none of the CH‐free cats were. All sampled parents were heterozygous for this recessive variant. This variant was found in 15 cat breeds with an estimated allele frequency of 9%.Conclusions and Clinical ImportanceDisproportionate dwarfism, abnormally high TSH and abnormally low to low‐normal T4 concentrations are diagnostic for CH in cats. All cases had dyshormonogenesis demonstrated by thyroid scintigraphy. This novel TPO missense variant (not described in humans) causes CH in cats and awareness of it can assist in diagnosis and breeding.

Rapid Resolution of Megaesophagus by Low-dose Levothyroxine in a Hypothyroid dog with Mitral Valve Degeneration

A 14-year-old intact female Maltese dog weighting 4.84kg was presented with acute regurgitation. At presentation, the dog was diagnosed with megaesophagus and primary hypothyroidism based on the radiography and thyroid-stimulating hormone stimulation test, respectively. Treatment was initiated with oral low-dose levothyroxine (0.0025 mg/kg b.w., orally, SID) considering underlying myxomatous mitral valve disease. Ten days after the management, the clinical and radiographic signs of megaesophagus were completely resolved. The dog was managed by levothyroxine administration with a gradual increase of the dose along with the monitoring of serum thyroxine concentrations since the dog was diagnosed with hypothyroidism. At 10 months after presentation, the dog continued to do well clinically. This is first case report describing rapid resolution of generalized megaesophagus after low-dose levothyroxine administration considering underlying cardiac disease in a hypothyroid dog.

Radioiodine treatment of hyperthyroidism in cats: results of 165 cats treated by an individualised dosing algorithm in Spain.

Although radioiodine (131I) is the treatment of choice for feline hyperthyroidism, 131I-dosing protocols commonly induce iatrogenic hypothyroidism and expose azotaemia. A recently reported patient-specific 131I dosing algorithm minimised the risk of 131I-induced hypothyroidism and azotaemia, while maintaining high cure rates. The aim of the study was to report results of 131I treatment in a European population of hyperthyroid cats using this patient-specific dosing algorithm. This prospective case series (before-and-after study) evaluated 165 hyperthyroid cats referred for 131I treatment. All cats had serum concentrations of thyroxine (T4), triiodothyronine (T3) and thyroid-stimulating hormone (TSH) measured (off methimazole ⩾1 week). Thyroid volume and percentage uptake of 99mTc-pertechnetate (TcTU) were determined using thyroid scintigraphy. An initial 131I dose was calculated by averaging dose scores for T4/T3 concentrations, thyroid volume and TcTU; 70% of that composite dose was then administered. Twenty-four hours later, percentage 131I uptake was measured, and additional 131I administered as needed to deliver an adequate radiation dose to the thyroid tumour(s). Serum concentrations of T4, TSH and creatinine were determined 6-12 months later. Median calculated 131I dose was 2.15 mCi (range 1.2-7.5), with only 51 (30.9%) receiving ⩾2.5 mCi. Of 165 cats, 124 (75.2%) became euthyroid, seven (4.2%) became overtly hypothyroid, 27 (16.4%) became subclinically hypothyroid and seven (4.2%) remained hyperthyroid. A higher proportion of overtly (85.7%) and subclinically (26.9%) hypothyroid cats developed azotaemia than euthyroid cats (13.6%; P = 0.0002). Hypothyroid cats were older (P = 0.016) and more likely to have detectable TSH concentrations (P = 0.025) and symmetrical bilateral distribution of 99mTc-pertechnetate uptake (P = 0.0002), whereas persistently hyperthyroid cats had higher severity scores (P = 0.012). Our results confirm that 131I dosing with this new algorithm results in high cure rates, with a lowered prevalence of 131I-induced overt hypothyroidism and azotaemia. Age, serum TSH concentrations, bilateral, symmetrical uptake and severity score help predict outcome.

The Impact of Rumen-Protected L-Arginine Oral Supplementation on Libido, Semen Quality, Reproductive Organ Biometry, and Serum Biochemical Parameters of Rams.

This study aimed to investigate the effect of oral supplementation of rumen-protected L-arginine on semen quality, testes, and accessory genital glands biometry in rams. Ten apparently healthy and fertile rams were randomly divided into two equal groups; control, and rumen-protected L-arginine (20 mg/Kg body weight for 30 days) treated group. In all rams, ultrasonographic measurements of the testes and the accessory genital glands and blood sampling were performed at day (D)10, D20, and D30 (D0 is the start of supplementation). Semen ejaculates were collected twice/week and semen quantity, and quality was examined. Our results showed that, in the L-arginine treated group, there were significant increase in the ultrasound biometric measurement of right seminal vesicle (RSV) and right Cowper's gland (RCG) at D10, both testes, tail of the epididymis (TE), SV, and CG of both sides at D20, and of both testes, RTE, RSV, RCG, and LSV at D30. Semen quality and quantity parameters were significantly improved in L-arginine treated group. Moreover, testosterone level in the L-arginine treated group was significantly higher than that in the Control group. Serum thyroxine and glutathione peroxidase concentrations were significantly higher in the L-arginine treated group. The present study concluded that oral supplementation with rumen-protected L-arginine is beneficial in improvement of rams' fertility.

Sublethal effects of acrylamide on thyroid hormones, complete blood count and micronucleus frequency of vertebrate model organism (Cyprinus carpio)

Abstract Objectives Acrylamide, a widely used chemical in industry, clinical laboratory and waste treatment plants, is considered a carcinogen in humans. The present study examined the hormonal, hematologic, and genotoxic responses in the invertebrate model common carp Cyprinus carpio after exposure to sublethal acrylamide. Methods Fish were exposed to acrylamide at 10 and 50 mg/L for 96 h, along with the respective control group. Serum levels of cortisol and thyroid hormones were measured using diagnostic ELISA direct immunoenzymatic kits. For micronucleus (MN) frequency assay, thin smears of the peripheral blood of fish were prepared. Results Serum levels of cortisol in both treatment groups considerably increased, which proposed that acrylamide caused a stress reaction of acrylamide exposed fish (p&lt;0.05). Fish demonstrated significant decreases in triiodothyronine (T3), free thyroxine (FT4), and free triiodothyronine (FT3) concentrations in a dose-dependent manner after acrylamide exposure (p&lt;0.05). However, serum thyroxine (T4) concentrations did not alter significantly in the treatment groups. Mean MN frequencies of fish erythrocytes increased significantly in acrylamide exposed groups suggesting that acrylamide is genotoxic in common carp (p&lt;0.05). The hematocrit, hemoglobin, and erythrocyte numbers of carp increased significantly in exposure groups (p&lt;0.05). Conclusions These results suggested that acrylamide can significantly affect the hemopoietic system. Furthermore, this study confirmed that the widespread use of acrylamide, even in sublethal concentrations, could affect the survival of non-target organisms, especially fish, in aquatic environments.