Plasma Growth Hormone Concentrations Research Articles

Influence of Silicon Supplementation on Growth, Immunity, Antioxidant, Hormonal Profile and Bone Health Biomarkers in Pre-ruminant Crossbred Calves.

Silicon (Si), a newer trace element, is believed to be important for healthy bone formation and to decrease bone resorption, improving the quality of bone by manipulating several hormones and enzymes. Therefore, the current investigation was conducted to determine the impact of Si supplementation on growth, immunity, antioxidant, hormonal profile and biomarkers of bone health in pre-ruminant crossbred calves. Twenty-four crossbred calves (5-7 days) were selected on the basis of their body weight (BW 31.65 ± 0.46 kg) and divided into 4 groups (n = 6) and fed as per ICAR (2013) feeding standards except that these were additionally supplemented with 0 (Si0), 50 (Si50), 100 (Si100) and 150 (Si150) mg of Si/kg dry matter (DM) in four respective groups for 90 days. Every month, peripheral blood samples were drawn (0, 30, 60 and 90 days post supplementing with Si) and analysed for antioxidant status, hormonal profile and bone health biomarkers. It is reported that dietary Si supplementation improved (P < 0.05) net body weight gain (kg), average daily gain (g) and average dry matter intake (kg), whereas feed intake (kg/100 kg BW), was not altered due to Si supplementation. Structural growth measurements were significantly higher (P < 0.05) in Si100 and Si150 groups as compared to Si50 and control groups. However, immune response (humoral as well as cell-mediated immunity), erythrocytic antioxidant enzymes (superoxide dismutase, SOD, glutathione peroxidase, GPx and catalase), plasma ferric reducing total antioxidant power (FRAP) activity and the plasma concentration of total immunoglobulins (TIg) remained unaffected by Si supplementation. Silicon increased (P < 0.05) the concentration of plasma growth hormone (GH), vitamin D3, bone alkaline phosphatase (BALP) and osteocalcin (OCN) in Si100 and Si150 groups, but the levels of calcitonin, parathyroid hormone (PTH) and hydroxyproline (HYP) remained similar among all the groups. As a result of the current investigation, it can be inferred that the inclusion of 100 and 150 mg of Si/kg DM was effective in improving the growth performance, growth hormone, vitamin D3 and bone health status in pre-ruminant calves. However, supplementation of 150 mg of Si/kg DM had no additional benefit; therefore 100 mg of Si/kg DM is the optimum level of Si supplementation in pre-ruminant calves.

Effect of Ca-octanoate supplementation on concentrations of ghrelin and ghrelin-related hormones in plasma and milk of beef cattle

We aimed to evaluate the effect of dietary calcium (Ca)-octanoate supplementation on concentrations of ghrelin, growth hormone (GH), insulin-like growth factor-1 (IGF-1), and insulin in plasma and milk of beef cattle during late gestation and early postpartum. Twelve Japanese Black cattle were offered concentrate without (CON, n = 6) or with Ca-octanoate supplementation at 1.5% of dietary dry matter (OCT, n = 6). Blood samples were collected at −60, −30, and −7 d relative to the expected parturition date and daily from d 0 to 3 after parturition. Milk samples were collected daily postpartum. Compared to the CON group, concentrations of acylated ghrelin increased in plasma as parturition approached in the OCT group (P = 0.02). However, concentrations of GH, IGF-1, and insulin in plasma and milk were not affected by treatment groups throughout the study. Additionally, we showed for the first time that bovine colostrum and transition milk contain acylated ghrelin at a significantly higher concentration than plasma (P = 0.01). Interestingly, concentrations of acylated ghrelin in milk were negatively correlated with those in plasma postpartum (r = −0.50, P < 0.01). Feeding Ca-octanoate increased concentrations of total cholesterol (T-cho) in plasma and milk (P < 0.05), tended to increase those of glucose in plasma at postpartum and milk (P < 0.1). We conclude that feeding Ca-octanoate in late gestation and early postpartum may contribute to increased concentrations of glucose and T-cho in plasma and milk without affecting concentrations of ghrelin, GH, IGF-1, and insulin in plasma and milk.

Ration Size and Protein Intake affect Circulating Growth Hormone Concentration, Hepatic Growth Hormone Binding and Plasma Insulin-Like Growth Factor-I Immunoreactivity in a Marine Teleost, the Gilthead Sea Bream (Sparus aurata)

The nutritional regulation of the growth hormone liver axis has been studied in gilthead sea bream (Sparus aurata). In a first study, fingerling fish were fed three experimental diets with varying proportions of protein (34, 45 and 55%). A 60% decrease in plasma growth hormone concentration was observed with the increase of specific growth rates and dietary protein levels. An opposite response was observed in hepatic growth hormone-binding sites and plasma insulin-like growth factor-I immunoreactivity that would reflect the insensitivity of liver to growth hormone action during relatively low protein intake. In a second study, fish were fed a commercial diet (55% protein) at different feeding levels (0, 1.2, 2.7 and 5.5 g/(100 g body wt·d). An 84% decrease in plasma growth hormone concentration was observed with the increase of specific growth rates and feeding levels from 0 to 2.7 g/(100 g body wt·d). However, significantly greater growth hormone concentration was found in fish fed 5.5 g/(100 g body wt·d) when compared with fish fed 2.7 g/(100 g body wt·d). Hepatic growth hormone-binding sites and plasma insulin-like growth factor-I immunoreactivity increased with the increase of feeding levels from 0 to 2.7 g/(100 g body wt·d), but these values were lower in fish-fed 5.5 g/(100 g body wt·d) than in those fed 2.7 g/(100 g body wt·d). The physiological importance of these results remains to be clarified, though probably it is a part of the mechanism that diminishes feed utilization for growth at high feeding levels. In any case, for fish of the same age, the increase of circulating growth hormone can be used as a reliable marker of impaired growth in marine fish such as gilthead sea bream.

Deletion of Jazf1 gene causes early growth retardation and insulin resistance in mice

Single-nucleotide polymorphisms in the human juxtaposed with another zinc finger protein 1 (JAZF1) gene have repeatedly been associated with both type 2 diabetes (T2D) and height in multiple genome-wide association studies (GWAS); however, the mechanism by which JAZF1 causes these traits is not yet known. To investigate the possible functional role of JAZF1 in growth and glucose metabolism in vivo, we generated Jazf1 knockout (KO) mice and examined body composition and insulin sensitivity both in young and adult mice by using 1H-nuclear magnetic resonance and hyperinsulinemic-euglycemic clamp techniques. Plasma concentrations of insulin-like growth factor 1 (IGF-1) were reduced in both young and adult Jazf1 KO mice, and young Jazf1 KO mice were shorter in stature than age-matched wild-type mice. Young Jazf1 KO mice manifested reduced fat mass, whereas adult Jazf1 KO mice manifested increased fat mass and reductions in lean body mass associated with increased plasma growth hormone (GH) concentrations. Adult Jazf1 KO manifested muscle insulin resistance that was further exacerbated by high-fat diet feeding. Gene set enrichment analysis in Jazf1 KO liver identified the hepatocyte hepatic nuclear factor 4 alpha (HNF4α), which was decreased in Jazf1 KO liver and in JAZF1 knockdown cells. Moreover, GH-inducedIGF-1 expression was inhibited by JAZF1 knockdown in human hepatocytes. Taken together these results demonstrate that reduction of JAZF1 leads to early growth retardation and late onset insulin resistance in vivo which may be mediated through alterations in the GH-IGF-1 axis and HNF4α.

Effect of dioscorea opposite waste on growth performance, blood parameters, rumen fermentation and rumen bacterial community in weaned lambs

This study investigated the effects of dioscorea opposite waste (DOW) on the growth performance, blood parameters, rumen fermentation and rumen microbiota of weaned lambs. Sixty healthy weaned Small-Tailed Han lambs (male, (22.68±2.56) kg initially) were used as the experimental animals. Four levels of concentrate: 0 (control, CON), 10% (DOW1), 15% (DOW2) and 20% (DOW3), were replaced with DOW in the basal diet as experimental treatments. The results showed that lambs fed the DOW2 diet had a higher (P<0.05) dry matter intake (DMI) than the other groups. There was no significant difference (P>0.05) among DOW groups in average daily weight gain (ADG), and replacing concentrate with DOW linearly or quadratically increased (P<0.05) the ADG, while lambs fed the DOW2 diet showed greater (P<0.05) ADG than the CON group. The relative plasma concentration of growth hormone (GH), insulin like growth factor-1 (IGF-1) and insulin were affected by DOW, replacing concentrate with DOW linearly or quadratically (P<0.05) enhanced the plasma concentration of GH, IGF-1 and insulin, which was significantly higher (P<0.05) in the DOW2 group than in the CON, DOW1 and DOW3 groups. In addition, the DOW treatment showed a lower (P<0.05) concentration of blood urea nitrogen (BUN) than the CON group. Replacing concentrate with DOW quadratically decreased (P<0.05) the ruminal ammonia nitrogen (NH3-N) and increased (P<0.05) the total of volatile fatty acids (TVFAs) at 0 and 4 h after feeding as well as linearly decreased (P<0.05) the NH3-N at 8 h after feeding. Replacing concentrate with DOW linearly decreased (P<0.05) the propionate and increased the aceate before feeding, and linearly decreased (P<0.05) propionate and quadratically increased (P<0.05) the aceate at 4 and 8 h after feeding. Lambs fed the DOW2 diet increased the phylum Firmicutes and genera Succiniclasticum and Ruminococcus_1 groups, whereas decreased (P<0.05) the relative abundance of phylum Deferribacteres and genera intestinimonas and Ruminiclostridium. In summary, replacing the concentrate with 15% DOW was beneficial for improving the rumen fermentation and ADG by increasing the DMI and modulating the rumen microbial community.

Effects of higher plasma growth hormone levels on subclinical ketosis in postpartum Holstein cows

Abstract Ketosis is a major metabolic disorder that can lead to huge economic losses in postpartum dairy cows by influencing milk production and reproduction performance. Therefore, it is very important to understand the characteristics and significance of plasma GH levels and dynamic changes in postpartum dairy cows for finding pathogenesis of subclinical ketosis (SK). The present study aimed to determine the role of growth hormone (GH) from the onset of SK to the fifth week postpartum and to explain the variations in GH, and metabolic markers namely, β-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA) and glucose (GLU) at early and later SK stages in postpartum Holstein cows. A 5-wk test and an intraday 12-h test were conducted in postpartum Holstein cows. Both tests were carried out every three hours from 10:00–22:00 for 7–14 days postpartum (12-h test: n = 16) to determine plasma concentrations of GH, BHBA, NEFA and GLU. The 5-wk test results showed that GH, BHBA and NEFA concentrations were significantly higher in the SK group during the five-weeks postpartum (p &lt; 0.01); GLU concentration was significantly lower in the SK group (p &lt; 0.01). Intraday 12-h test results revealed that the feeding time affected the plasma concentrations of GH, BHBA, NEFA and GLU. After 1-h of feeding time, GH concentrations decreased, while BHBA, NEFA and GLU concentrations increased. After 4-h of feeding time GH, BHBA and NEFA had the highest plasma concentrations, and GLU the lowest. In both experiments, GH was positively correlated with BHBA, NEFA, and negatively correlated with GLU. It can be suggested that GH has a potential role in development and aetiology of subclinical ketosis.

Dietary L-citrulline modulates the growth performance, amino acid profile, and the growth hormone/insulin-like growth factor axis in broilers exposed to high temperature.

Heat stress adversely affects the growth performance, muscle development, and protein metabolism in poultry. l-Citrulline (L-Cit), is a non-essential amino acid that is known to stimulate muscle protein synthesis under stress conditions. This study investigated whether L-Cit could influence the growth performance, amino acid profile, and protein metabolism in broilers exposed to high ambient temperature. In a 2 × 2 factorial arrangement, Arbor acre broilers (288 chickens) were fed with basal diet (CON) or 1% L-Cit supplemented diet and later subjected to either thermoneutral (TNZ: 24°C, 24 h/d) or heat stress (HS: 35°C for 8 h/d) environment for 21 days. The results showed that L-Cit diet promoted the body weight and body weight gain of broilers higher than the CON diet, and it further alleviated HS suppression of body weight and feed intake at certain periods (p < 0.05). Plasma urea, uric acid, glucose, and total cholesterol were elevated during HS, whereas, the triglyceride content was decreased (p < 0.05). Serum amino acids including citrulline, alanine, aspartate, and taurine were decreased by HS. L-Cit supplementation restored the citrulline level and alleviated HS induction of 3-methylhistidine (p < 0.05). L-Cit supplementation increased the plasma growth hormone (GH) and insulin-like growth factor-1 (IGF-1) concentration, as well as the GH concentration in the breast muscle (p < 0.05). The mRNA expression showed that HS elicited tissue-specific responses by upregulating some growth factors in the breast muscle, but downregulated the GH receptor, GH binding protein, and IGF-1 expression in the hypothalamus. L-Cit supplementation upregulated the GHRH and IGFBP2 expression in the hypothalamus. L-Cit also upregulated the expression of IGF-1R and IGFBP2 in the breast muscle of HS broilers. The total mTOR protein level in the breast muscle of HS broilers was also increased by L-Cit diet (p < 0.05). Therefore, this study demonstrated that HS negatively affected the growth performance of broilers and dysregulated the expression of growth factors related to protein metabolism. Contrarily, L-Cit promoted the growth responses of broilers via its stimulation of circulating GH/IGF-1 concentration. To certain extents, L-Cit supplementation elicited protective effects on the growth performance of HS broilers by diminishing protein catabolism.

Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype.

A greater decrease in 24-hour energy expenditure (24hEE) during short-term fasting is indicative of a thrifty phenotype. As ghrelin and the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis are implicated in the regulation of energy intake and metabolism, we investigated whether ghrelin, GH, and IGF-1 concentrations mediate the fasting-induced decrease in 24hEE that characterizes thriftiness. In 47 healthy individuals, 24hEE was measured in a whole-room indirect calorimeter both during 24-hour eucaloric and fasting conditions. Plasma total ghrelin, GH, and IGF-1 concentrations were measured by enzyme-linked immunosorbent assay after an overnight fast the morning before and after each 24-hour session. During 24-hour fasting, on average 24hEE decreased by 8.0% (P < .001), GH increased by ~5-fold (P < .001), whereas ghrelin (mean +23 pg/mL) and IGF-1 were unchanged (both P ≥ .19) despite a large interindividual variability in ghrelin change (SD 150 pg/mL). Greater fasting-induced increase in ghrelin was associated with a greater decrease in 24hEE during 24-hour fasting (r = -0.42, P = .003), such that individuals who increased ghrelin by 200 pg/mL showed an average decrease in 24hEE by 55 kcal/day. Short-term fasting induced selective changes in the ghrelin/GH/IGF-1 axis, specifically a ghrelin-independent GH hypersecretion that did not translate into increased IGF-1 concentrations. Greater increase in ghrelin after 24-hour fasting was associated with greater decrease in 24hEE, indicating ghrelin as a novel biomarker of increased energy efficiency of the thrifty phenotype.

LEAP2 reduces postprandial glucose excursions and ad libitum food intake in healthy men

SummaryThe gastric hormone ghrelin stimulates food intake and increases plasma glucose through activation of the growth hormone secretagogue receptor (GHSR). Liver-expressed antimicrobial peptide 2 (LEAP2) has been proposed to inhibit actions of ghrelin through inverse effects on GHSR activity. Here, we investigate the effects of exogenous LEAP2 on postprandial glucose metabolism and ad libitum food intake in a randomized, double-blind, placebo-controlled, crossover trial of 20 healthy men. We report that LEAP2 infusion lowers postprandial plasma glucose and growth hormone concentrations and decreases food intake during an ad libitum meal test. In wild-type mice, plasma glucose and food intake are reduced by LEAP2 dosing, but not in GHSR-null mice, pointing to GHSR as a potential mediator of LEAP2’s glucoregulatory and appetite-suppressing effects in mice.

Effect of oral melatonin on plasma growth hormone concentration in rhesus monkeys (Macaca mulatta)

Effect of oral melatonin on plasma growth hormone concentration in rhesus monkeys (Macaca mulatta)

Research Note: Development of a sandwich ELISA for determining plasma growth hormone concentrations in goose

Growth hormone (GH) is required for normal postnatal development in poultry; however, no immunoassay exists to assess its levels in geese plasma, hindering the study of endocrine regulation in this species. We developed a sandwich ELISA to determine the GH concentrations in the plasma of geese. Recombinant goose GH was produced using a eukaryotic expression system and purified for use as the reference standard in ELISA and the antigen for producing the polyclonal antibodies in rabbits. Rabbit anti-goose GH polyclonal antibody was used to coat the wells of the ELISA plate, and its biotinylated form served as the detection antibody. An avidin-conjugated horseradish peroxidase was used to bind the detection antibody and catalyze the chromogenic reaction of 3,3,5,5-tetramethylbenzidine and H2O2. A sigmoidal curve was fitted to the optical density and the log of the standard GH concentration using the four-parameter logistic model. The sensitivity of the assay was less than 0.156 ng/mL. The intra- and interassay coefficients of variation were less than 9 and 13%, respectively. The response curve of the serially diluted plasma samples from geese exhibited a good parallel relationship with that observed for the reference standards. The assay effectively detected differences in GH concentrations in plasma samples from geese at various physiological stages; thus, it will be useful for future study of their growth and metabolism.

Survival outcomes, hematologic complications and growth impairment after sequential chemoradiotherapy in intracranial NGGCTs: aretrospective study.

This study aimed to evaluate the clinical features, prognostic factors, and survival outcomes for patients with intracranial nongerminomatous germ cell tumors (NGGCTs), with aparticular focus on treatment toxicity for long-term survivors. Intracranial NGGCTs treated with platinum-based chemotherapy and craniospinal irradiation (CSI) in our institution were retrospectively analyzed. Hematological complications following sequential chemoradiotherapy as well as height and weight in childhood survivors were evaluated. Plasma growth hormone (GH) concentrations prior to and after radiotherapy were obtained for the comparisons. Atotal of 111 intracranial NGGCTs were included. The 3‑year overall survival (OS) and event-free survival (EFS) rates were 83.5% ± 3.9% and 71.0% ± 4.8%, respectively. Acombined treatment modality consisting of ≥ 4cycles of platinum-based chemotherapy and CSI was associated with an improved OS (P = 0.003) and EFS (P < 0.001). Thrombocytopenia of any grade occurred in 35.4% (34/96) of patients, and the threshold age for an increased risk of thrombocytopenia was 14 years (area under the curve AUC = 0.752, P < 0.0001) as derived from receiver operating characteristic (ROC) analysis. Growth impediment was found in 8of 56(14%) patients. The age for receiving radiotherapy was found to inversely correlate with height development, revealing acut-off age of 11.5 years for risking growth impairment (AUC = 0.806, P = 0.004). Consistently, asignificant decline in plasma growth hormone after radiotherapy was observed in patients ≤ 11.5 years (P < 0.01) but not patients > 11.5 years. (P > 0.05). Our study suggested that acombined treatment modality with at least four cycles of chemotherapy and CSI was safe and effective for patients with intracranial NGGCTs. Radiotherapy should be used with caution for patients < 11.5 years due to growth impairment.

PSII-B-25 Age-related changes in growth hormone-insulin like growth factor 1 axis-regulating factors and metabolic hormones in Korean cattle steer

Abstract Meat yield is important for beef industry for maximum profits. Enhancing muscle growth by promoting hypertrophy of muscle fiber is required for increasing meat yield. Growth hormone (GH)-insulin like growth factor 1 (IGF1) axis and metabolic hormones have a central role for regulating hypertrophy of muscle fiber. We investigated age-related changes in GH-IGF1 axis-regulating factors and metabolic hormones in beef cattle. Ten Korean cattle steers were used. The longissimus thoracis (LT) samples were biopsied between the 11th and 12th rib at 12, 18, and 24 months of age. Steers were slaughtered at 34 month of age and the LT samples were collected. The LT samples were used for histological observation of muscle fiber size and detection of mRNA levels by real-time PCR analysis. Blood was collected at 12, 18, 24, and 34 months of age and used for hormone analyses. The mean muscle fiber size increased (P &amp;lt; 0.01) from 12 to 24 months, and remained unchanged at 34 months. Plasma GH concentrations were unchanged with age, whereas circulating IGF-1 concentrations decreased (P &amp;lt; 0.001) with age. Testosterone and insulin concentrations increased from 12 to 24 months and remained unchanged at 34 months. Leptin concentrations were unchanged from 12 to 24 months and increased at 34 months. The mRNA levels of growth hormone receptor (GHR) and signal transducer and activator of transcription 5a/b (STAT5a/b) decreased (P &amp;lt; 0.01) from 12 to 24 months, whereas mRNA levels of IGF-1 gene increased (P &amp;lt; 0.001) with age. Results indicate that the increased muscle fiber size in LT from 12 to 24 months are characterized with increasing concentrations of circulating testosterone and insulin. Age-dependent changes in muscle fiber hypertrophy were also related with changes in GHR, STAT5a/b, IGF-1 mRNA levels in the LT.

Cysteamine administration in lambs grazing on mountain pastures: Effects on the body weight, antioxidant capacity, thyroid hormones and growth hormone secretion.

This study aimed to evaluate the effects of intravenous injection of cysteamine (CS) on body weight (BW), growth hormone (GH), thyroid hormones (TH) secretion, and antioxidant status of growing lambs grazing on mountain pastures. Fifteen lambs (3–4 months of age) were randomly allocated into three experimental groups which received different dosages of CS: 0, 20, and 50 mg/kg BW−1. The CS was injected on the 1st, 10th, and 20th days of the experiment to the lambs through the jugular vein. Assessment of plasma concentration of GH and TH hormones was carried out at days 0 (a day before the start of CS injections), 15, and 30 of the experiment. The antioxidant enzymes were measured at the end of the experiment. Lambs were weighed at days 0, 10, 20, and 30 of the experiment. The results showed that treatment and time affected the BW, GH, triiodothyronine (T3), and tetraiodothyronine (T4) secretion. The intravenous injection of CS increased the BW of growing lambs (p < 0.01) and increased the plasma concentration of GH, T3, and T4 (p < 0.01). The treatment also enhanced glutathione peroxidase (GSH‐Px; p < 0.05) and reduced malondialdehyde concentrations (MDA; p < 0.01). Total antioxidant capacity (T‐AOC) level reduced in CS‐1 treatment compared to GC and CS‐2 treatments (p < 0.01). The levels of superoxide dismutase (SOD) and catalase (CAT) were not affected by CS. In conclusion, intravenous injection of CS improved BW, GH, and TH concentrations and antioxidant capacity in growing lambs grazing on mountain pastures.

Small for Gestational Age Preterm Neonates Exhibit Defective GH/IGF1 Signaling Pathway.

Objective: To investigate the impact of fetal growth restriction (FGR) on hormonal regulation of post-natal growth and glucose metabolism [via insulin and growth hormone (GH)/Insulin-like Growth factor 1 (IGF1) axis pathways] in small for gestational age (SGA) neonates.Methods: We conducted a monocentric observational prospective comparative study on 73 singleton babies born with a weight inferior to 2,000 g. We analyzed auxological (weight, height and head circumference), and hormonal (GH, IGF1, and insulin plasma concentrations) data comparing SGA and appropriate for gestational age (AGA) neonates, between day 1 and 60.Results: One third (23/73) of the neonates were SGA. Twenty-five percent (18/73) required insulin for idiopathic hyperglycemia of prematurity and were smaller in weight and head circumference at discharge. In the SGA group compared with the AGA group, GH plasma concentrations were higher at day 3 (70.1 vs. 38.0 mIU/L) and IGF1 plasma concentrations were higher at day 10 (29.0 vs. 18.7 ng/ml).Conclusions: SGA neonates displayed resistance to GH and IGF1, concomitant to insulin resistance. This could partially explain the initial defective catch-up growth and, later in life, the higher prevalence of metabolic syndrome in this population.

19 Interaction of kisspeptin and the somatotropic and lactotropic axes in mares and geldings

Several experiments were conducted to investigate the interaction between kisspeptin and the somatotropic and lactotropic axes in mares and geldings. Light horse, diestrous mares and geldings, weighing approximately 500 kg and aged 6 to 24 years, were randomly assigned to treatment with 1 mg equine kisspeptin-10 (Kp10; n = 10) or 1 mL saline (n = 9), i.v. Blood samples were collected via jugular venipuncture −10, 0, 5, 10, 15, 20 and 30 min relative to treatment. Plasma concentrations of growth hormone (GH) and prolactin (PRL) were determined by RIA and means compared using ANOVA with repeated sampling. Neither GH nor PRL were stimulated by Kp10. In a second experiment, 30 mares and geldings were used to determine if pre-treatment with estradiol or progesterone would elicit a GH or PRL response to Kp10. Five mares and 5 geldings each were assigned to pre-treatment with 50 mg estradiol cypionate in oil (ECP), 600 mg long-acting progesterone, or oil only, i.m. Two days later, all horses received 1 mg Kp10 in saline, i.v., and blood sampling occurred 0, 5, 10, 15 and 20 min relative to Kp10 administration. Mean GH and PRL concentrations and area under the curve were compared by ANOVA. No stimulation of GH or PRL was observed. In a third experiment, 12 diestrous mares, confirmed by plasma progesterone and ultrasound findings, were randomly assigned to treatment with 1 mg Kp10 (n = 6) or 1 mL saline (n = 6) followed by the dopamine antagonist, sulpiride (0.01 mg/kg body weight), 5 min later. Blood sampling occurred 0, 5, 10 and 15 min relative to sulpiride administration. Sulpiride stimulated PRL ( P < 0.0001) in both groups of mares; however, PRL concentrations were lower ( P ≤ 0.01) in Kp10-treated mares compared with saline-treated mares. To determine if estrogen altered the PRL response to sulpiride, 12 seasonally anovulatory mares, confirmed by plasma progesterone and ultrasound findings, were used in a fourth experiment and randomly assigned to receive 50 mg ECP (n = 6) or oil (n = 6), i.m. The next day, mares were challenged with sulpiride. Treatment and blood sampling occurred as described in experiment 3. Plasma PRL was stimulated ( P < 0.001) in both groups of mares and responses were similar between treatments. In the described experiments, 1 mg Kp10 given as a bolus failed to stimulate circulating GH or PRL within 30 min in mares or geldings regardless of steroid milieu. This is in contrast to reports of GH stimulation in ruminants. Kp10 did alter the PRL response to sulpiride in diestrous mares, perhaps suggesting an interaction between Kp10 and dopaminergic input to the pituitary in a progesterone dominant environment.

Evaluation of hypophysectomy for treatment of hypersomatotropism in 25 cats.

BackgroundSuccessful treatment of cats with hypersomatotropism by transsphenoidal hypophysectomy is described in small numbers of cats.ObjectivesTo describe the endocrine profile, survival, and remission rates of hypersomatotropism and diabetes mellitus in a cohort of cats with hypersomatotropism that underwent hypophysectomy between 2008 and 2020.AnimalsTwenty‐five client‐owned cats with spontaneous hypersomatotropism.MethodsRetrospective study. Diagnosis of hypersomatotropism was based on clinical signs, plasma insulin‐like growth factor‐1 (IGF‐1) concentration, and imaging of the pituitary gland. Growth hormone (GH) and IGF‐1 concentrations were measured repeatedly after surgery. Survival times were calculated based on follow‐up information from owners and referring veterinarians.ResultsMedian postoperative hospital stay was 7 days (range, 3‐18 days). One cat died within 4 weeks of surgery. Median plasma GH concentration decreased significantly from 51.0 ng/mL (range, 5.0‐101.0 ng/mL) before surgery to 3.8 ng/mL (range, 0.6‐13.0 ng/mL) at 5 hours after surgery. Remission of hypersomatotropism, defined as normalization of plasma IGF‐1 concentration, occurred in 23/24 cats (median, 34 ng/mL; range, 14‐240 ng/mL) and 22/24 cats entered diabetic remission. Median survival time was 1347 days (95% confidence interval, 900‐1794 days; range, 11‐3180 days) and the overall 1‐, 2‐, and 3‐year all‐cause survival rates were 76%, 76%, and 52%, respectively.Conclusions and Clinical ImportanceThis study shows the beneficial outcome of hypophysectomy in cats with hypersomatotropism, marked by low death rate and a high percentage of diabetic remission and definitive cure.

Effect of walking exercise and nutritional plan on goat performance

This study evaluated the effects of walking exercise and nutritional plan on metabolic variables and the growth of stabled goats. Thirty-six goats [body weight (BW) = 21 ± 0.3 kg] were allocated in individual pens, and the treatments were randomly assigned to the animals in a 2 × 2 factorial design. The treatments consisted of walking exercise (7,5 km/day) or not and two nutritional plans [90 % (0.9M) or 170 % (1.7M) of the maintenance requirements] for 50 days (first period) . Further, all animals were fed a diet that met 170 % of their maintenance requirements and were not subjected to exercise for more 35 days (second period). There was no interaction effect between walking and nutritional plan for any of the studied variables. Walking exercise did not affect rib-eye area (REA; P = 0.13) or subcutaneous fat thickness (SFT; P = 0.11), but reduced body weight (BW) in the first (P = 0.03) and second (P = 0.03) periods. The animals in the 0.9M nutritional plan group exhibited lower REA and SFT values than those in the 1.7M group. This was accompanied by a decrease in plasma triiodothyronine concentration (T3; P = 0.03) in the animals that received the 0.9M plan in the first period. Exercise and nutritional plan, respectively, did not change (P ≥ 0.17) the plasma concentration of growth hormone (P = 0.31; P = 0.17), the gene expression of growth hormone receptors (GHR; P = 0.85; P = 0.79), insulin-like growth factor 1 (IGF-I; P = 0.87; P = 0.77), insulin-like growth factor 1 receptor (IGF1R; P = 0.55; P = 0.63) or peroxisome proliferator-activated receptors alpha (PPARα; P = 0.90; P = 0.92). In the second period, the BW and REA of the goats in the 0.9M group remained lower than those observed in the 1.7M group (23.33 vs. 30.37; P < 0.0001). Plasma T3 levels returned to values similar to those obtained with the 1.7M plan at the end of the second period (1.20 vs. 1.23; P = 0.03). Walking reduces the BW of goats without changing rib-eye area, subcutaneous fat deposition on the Longissimus muscle or gene expression. Nutritional restriction through a diet that meets 90 % of the maintenance requirements reduces weight gain but does not induce a full compensatory growth in goats.

Metabolic and hormonal control of energy utilization and partitioning from early to mid lactation in Sarda ewes and Saanen goats

In a recent study, we observed that starch-rich diets used in mid lactation induced lower milk production persistency and higher body fat accumulation in dairy ewes compared with dairy goats. Because these species differences could be linked to hormonal mechanisms that drive energy partitioning, in the same experiment, we explored the evolution of metabolic and hormonal status during lactation to test this hypothesis. Twenty mature Sarda dairy ewes and 20 mature Saanen goats [15-134 ± 11 d in milk (DIM), mean ± SD] were compared simultaneously. In early lactation, each species was allocated to one dietary treatment: high-starch diet [HS: 20.4% starch, on dry matter (DM) basis], whereas from 92 ± 11 DIM, each species was allocated to 1 of 2 dietary treatments: HS (20.0% starch, on DM basis) and low-starch (LS: 7.8% starch, on DM basis) diets. Blood samples were collected in the morning to analyze glucose, nonesterified fatty acids (NEFA), growth hormone (GH), insulin, and insulin-like growth factor I (IGF-I). Data were analyzed using the PROC MIXED procedure of SAS with repeated measurements (SAS Version 9.0). The HS and LS diets applied in mid lactation did not affect metabolic status of the animal within species; thus, only a comparison between species was carried out. From early to mid lactation, plasma glucose concentration was higher in ewes than in goats (54.57 vs. 48.35 ± 1.18 mg/dL), whereas plasma NEFA concentration was greater in goats than in ewes (0.31 vs. 0.25 ± 0.03 mmol/L). Goats had higher plasma GH concentration and lower plasma insulin content than ewes (4.78 vs. 1.31 ng/mL ± 0.47; 0.11 vs. 0.26 μg/L ± 0.02). Plasma IGF-I concentration did not vary between species. The comparison of metabolic and hormonal status of lactating Sarda dairy ewes and Saanen goats, carried out by studying simultaneously the 2 species in the same stage of lactation and experimental conditions, suggests that the higher insulin and glucose concentration observed in Sarda ewes explains why they partitioned more energy toward body reserves than to the mammary gland, especially in mid lactation. This can justify the negative effect of high-starch diets in mid-lactating Sarda ewes. Conversely, the highest GH and NEFA concentration observed in Saanen goats explain why they partitioned more energy of starch diets toward the mammary gland than to body reserves and justify the positive effect of high-starch diet in mid lactation. Together, these different responses contribute to explain why specialized dairy goats, such as the Saanen breed, have a higher milk production persistency than specialized dairy sheep breeds, such as the Sarda.

Interactive Effects of Copper Sources and a High Level of Phytase in Phosphorus-Deficient Diets on Growth Performance, Nutrient Digestibility, Tissue Mineral Concentrations, and Plasma Parameters in Nursery Pigs

The present study investigated the interactive effects of copper sources and a high level of phytase on growth performance, nutrient digestibility, tissue mineral concentrations, and plasma parameters in nursery pigs. Weaning piglets (N = 192; 6.06 ± 0.99 kg), blocked by body weight, were randomly allotted to 1 of 4 dietary treatments, with 12 pens per treatment and 4 pigs per pen. A basal diet for each phase was formulated to meet nutrient requirements for nursery pigs with the exception that standardized total tract digestibility (STTD) P was reduced by 0.12% and Ca was adjusted to achieve Ca/STTD P = 2.15. The 4 dietary treatments were arranged in a 2 × 2 factorial design, with 2 Cu sources (125 mg/kg Cu from copper methionine hydroxy analogue chelate (Cu-MHAC) or copper sulfate (CuSO4)) and 2 phytase levels (0 or 1500 phytase units (FTU)/kg). Results showed that there was an interaction (P < 0.05) between Cu sources and phytase on ADG during days 0–41. When phytase was not present in the diets (P deficient), there was no difference between the two Cu sources in terms of ADG during days 0–41, whereas with phytase in the diets, Cu-MHAC tended to improve (P < 0.10) ADG during days 0–41 compared with CuSO4. Pigs fed Cu-MHAC had greater apparent total tract digestibility (ATTD) of neutral and acid detergent fiber and STTD of P than those fed CuSO4. Phytase increased (P < 0.05) growth performance, ATTD of Ca and P, and plasma inositol and growth hormone concentrations. In conclusion, Cu-MHAC may be more effective in improving growth rate than CuSO4 when phytase was supplemented at 1500 FTU/kg. Cu-MHAC enhanced fiber and P digestibility regardless of phytase, compared with CuSO4. Phytase addition in P-deficient diets was effective in improving growth performance, Ca and P digestibility, and plasma inositol and growth hormone concentrations.