scholarly journals Effects of chromium supplementation on physiology, feed intake, and insulin related metabolism in growing pigs subjected to heat stress

2017 ◽  
Vol 1 (1) ◽  
pp. 116-125 ◽  
Author(s):  
F. Liu ◽  
J. J. Cottrell ◽  
U. Wijesiriwardana ◽  
F. W. Kelly ◽  
S. S. Chauhan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Insulin Sensitivity ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Feed Intake ◽  
Insulin Response ◽  
Thermal Exposure ◽  
Growing Pigs ◽  
Model Assessment ◽  
Intravenous Glucose

Abstract Improving insulin sensitivity may reduce impacts of heat stress (HS) in pigs by facilitating heat dissipation. Chromium (Cr) has been reported to improve insulin sensitivity in pigs. Therefore, the aim of this experiment was to investigate whether Cr supplementation can mitigate HS in growing pigs. Thirty-six gilts were randomly assigned to 2 diets containing 0 (control) or 400 ppb Cr. After 14 d the supplemented pigs were allocated to either 8 d thermoneutral (20°C constant; TN) or cyclic HS (35°C, 0900 h to 1700 h) conditions and continued their respective diet (n = 9 per group). Growth performance was recorded during the 14-d supplementation period. The physiological responses to HS were monitored by measuring respiration rate, rectal temperature, blood gas chemistry, and feed intake during thermal exposure. Kinetics of plasma glucose, insulin and NEFA were studied by intravenous glucose tolerance test (IVGTT) on d 8 of thermal treatment. Results showed Cr alleviated the HS-increased rectal temperature (P < 0.05) and respiration rate (P < 0.01) at 1300 h and 1600 h during thermal exposure. However, Cr did not mitigate the reduction in average daily feed intake which was reduced by 35% during HS or the HS-induced respiratory alkalosis. Chromium tended to increase average daily gain (0.86 vs. 0.95 kg, P = 0.070) during the 14-d supplementation under TN conditions before thermal exposure, which might be associated with the potential of Cr in improving overall insulin sensitivity, as evidenced by a reduced insulin resistance index calculated by Homeostatic Model Assessment (HOMA-IR; 0.65 vs. 0.51, P = 0.013) and a tendency of reduced fasting plasma insulin concentration (1.97 vs. 1.67 μU/mL, P = 0.094). Heat stress decreased the acute insulin releasing rate (P = 0.012) and consequently slowed glucose clearance rate (P = 0.035) during IVGTT. Besides, HS enlarged the values of area under the curve of NEFA during IVGTT (P < 0.01), indicating a reduced lipid mobilization. In conclusion, HS reduced insulin response to IVGTT. Chromium supplementation exhibited a potential in improving insulin sensitivity and mitigating HS symptoms in growing pigs.

scholarly journals Comparison of insulin sensitivity between healthy neonatal foals and horses using minimal model analysis

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262584
Author(s):  
Hannah M. Kinsella ◽  
Laura D. Hostnik ◽  
Hailey A. Snyder ◽  
Sarah E. Mazur ◽  
Ahmed M. Kamr ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Minimal Model ◽  
Cell Function ◽  
Insulin Response ◽  
Model Analysis ◽  
Intravenous Glucose Tolerance Test ◽  
Model Assessment ◽  
Intravenous Glucose ◽  
Glucose Ratio

The equine neonate is considered to have impaired glucose tolerance due to delayed maturation of the pancreatic endocrine system. Few studies have investigated insulin sensitivity in newborn foals using dynamic testing methods. The objective of this study was to assess insulin sensitivity by comparing the insulin-modified frequently sampled intravenous glucose tolerance test (I-FSIGTT) between neonatal foals and adult horses. This study was performed on healthy neonatal foals (n = 12), 24 to 60 hours of age, and horses (n = 8), 3 to 14 years of age using dextrose (300 mg/kg IV) and insulin (0.02 IU/kg IV). Insulin sensitivity (SI), acute insulin response to glucose (AIRg), glucose effectiveness (Sg), and disposition index (DI) were calculated using minimal model analysis. Proxy measurements were calculated using fasting insulin and glucose concentrations. Nonparametric statistical methods were used for analysis and reported as median and interquartile range (IQR). SI was significantly higher in foals (18.3 L·min-1· μIU-1 [13.4–28.4]) compared to horses (0.9 L·min-1· μIU-1 [0.5–1.1]); (p < 0.0001). DI was higher in foals (12 × 103 [8 × 103−14 × 103]) compared to horses (4 × 102 [2 × 102−7 × 102]); (p < 0.0001). AIRg and Sg were not different between foals and horses. The modified insulin to glucose ratio (MIRG) was lower in foals (1.72 μIUinsulin2/10·L·mgglucose [1.43–2.68]) compared to horses (3.91 μIU insulin2/10·L·mgglucose [2.57–7.89]); (p = 0.009). The homeostasis model assessment of beta cell function (HOMA-BC%) was higher in horses (78.4% [43–116]) compared to foals (23.2% [17.8–42.2]); (p = 0.0096). Our results suggest that healthy neonatal foals are insulin sensitive in the first days of life, which contradicts current literature regarding the equine neonate. Newborn foals may be more insulin sensitive immediately after birth as an evolutionary adaptation to conserve energy during the transition to extrauterine life.

scholarly journals 236 Effects of mitoquinol during acute heat stress exposure in growing pigs

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 118-118
Author(s):  
Edith J Mayorga ◽  
Erin A Horst ◽  
Brady M Goetz ◽  
Sonia Rodríguez-Jiménez ◽  
Megan A Abeyta ◽  
...  
Keyword(s):  
Heat Stress ◽  
Fatty Acid ◽  
Skin Temperature ◽  
Blood Urea Nitrogen ◽  
Rectal Temperature ◽  
Feed Intake ◽  
Growing Pigs ◽  
Stress Exposure ◽  
Acute Heat Stress ◽  
Ad Libitum

Abstract Objectives were to determine the effects of mitoquinol (MitoQ) on performance, metabolism, and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 59±1 kg BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and MitoQ (n=8; TNMitoQ), 3) HS control (n=8; HSCtl), or 4) HS and MitoQ (n=8; HSMitoQ). The trial consisted of two experimental periods (P). During P1 (2d), pigs were fed ad libitum and housed in TN conditions (20.6±0.1°C). During P2 (24h), HSCtl and HSMitoQ pigs were exposed to continuous HS (35.2±0.03°C); while TNCtl and TNMitoQ remained in TN conditions. Mitoquinol was orally administered twice daily (0700 and 1800 h; 40 mg/d) during P1 and P2. Pigs exposed to HS had increased rectal temperature, skin temperature, and respiration rate (1.46°C, 6.79°C, and 101 bpm, respectively; P&lt; 0.01) compared to their TN counterparts. Acute HS markedly decreased feed intake (67%; P&lt; 0.01). Additionally, HS pigs lost BW compared to their TN counterparts (-4.7 vs. +1.6 kg, respectively; P&lt; 0.01); however, the reduction in BW was less severe in HSMitoQ compared to HSCtl pigs (-3.85 vs. -5.50 kg, respectively; P&lt; 0.01). Circulating glucose increased in HSMitoQ relative to HSCtl pigs (15%; P=0.04). Non-esterified fatty acid (NEFA) concentrations were increased in HS compared to TN pigs (P&lt; 0.01), although this difference was influenced by increased NEFA in HSCtl relative to HSMitoQ pigs (251 vs. 142 μEq/L; P&lt; 0.01). Insulin:feed intake tended to increase in HS relative to TN pigs (P=0.09). Overall, no differences in blood urea nitrogen or cell blood counts were observed across treatments (P &gt;0.10). In conclusion, acute HS exposure negatively altered animal performance and metabolism; however, administering MitoQ appeared to ameliorate the HS response.

scholarly journals Field Trial on Glucose-Induced Insulin Response in High-Yielding Dairy Cows under Different Environmental Temperatures

2017 ◽  
Vol 67 (3) ◽  
pp. 366-382
Author(s):  
Ivan Vujanac ◽  
Radiša Prodanović ◽  
Goran Korićanac ◽  
Jovan Bojkovski ◽  
Predrag Simeunović ◽  
...  
Keyword(s):  
Heat Stress ◽  
Glucose Tolerance ◽  
Milk Production ◽  
Basal Insulin ◽  
Insulin Response ◽  
Area Under The Curve ◽  
Tolerance Test ◽  
Intravenous Glucose Tolerance Test ◽  
Model Assessment ◽  
Intravenous Glucose

AbstractThis study aimed to evaluate glucose-induced insulin response in cows exposed to different temperature-humidity index. Twenty early lactating Holstein-Friesian cows were divided into 2 equal groups based on season, as summer (SU) and spring (SP). SP cows were not exposed to heat stress, while SU cows were exposed to moderate or severe heat stress. Milk production was recorded daily. Starting from day 30 of lactation, intravenous glucose tolerance test (IVGTT) was carried out three times at 30-day intervals. Blood samples were taken before (basal) and after glucose infusion, and glucose and insulin were measured at each sample point. The homeostatic model assessment (HOMA) index was calculated. Milk yield from days 30 to 40 and 64 to 90 of lactation were higher in SP cows than in SU cows. Basal glucose did not differ on days 30 and 60 of lactation, while basal insulin and HOMA were lower in SU compared to SP cows. On day 90 of lactation, SU cows had higher basal glucose, whereas basal insulin and HOMA did not differ. IVGTT results revealed that glucose tolerance was affected by heat stress such that SU cows had higher glucose clearance. Insulin responses to IVGTT did not differ on days 30 and 60 of lactation. Heat stress had a marked effect on insulin secretion on day 90 of lactation, illustrated by higher increments, peak concentrations and area under the curve for insulin in SU cows. Overall, season differences in glucose tolerance depend not only on heat stress and milk production but also on the stage of lactation.

scholarly journals The Effect of Heat Stress on Respiratory Alkalosis and Insulin Sensitivity in Cinnamon Supplemented Pigs

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 690
Author(s):  
Jeremy J. Cottrell ◽  
John B. Furness ◽  
Udani A. Wijesiriwardana ◽  
Mitchell Ringuet ◽  
Fan Liu ◽  
...  
Keyword(s):  
Heat Stress ◽  
Insulin Sensitivity ◽  
Heat Waves ◽  
Insulin Response ◽  
Respiratory Alkalosis ◽  
Tolerance Test ◽  
Intravenous Glucose Tolerance Test ◽  
Large White ◽  
Intravenous Glucose ◽  
Increase Insulin Sensitivity

With increases in the frequency, intensity and duration of heat waves forecast plus expansion of tropical agriculture, heat stress (HS) is both a current and an emerging problem. As cinnamon has been shown to increase insulin sensitivity, which is part of the adaptive response to HS, the aim of this experiment was to determine if cinnamon could improve insulin sensitivity and ameliorate HS in grower pigs. In a 2 × 2 factorial design, 36 female Large White × Landrace pigs were fed control (0%) vs. cinnamon (1.5%) diets and housed for 7 day under thermoneutral (20 °C, TN) vs. HS conditions (8 h 35 °C/16 h 28 °C, 35% relative humidity). At the completion of the challenge, insulin sensitivity was assessed by an intravenous glucose tolerance test (IVGTT). Heat stress increased parameters such as respiration rate and rectal temperature. Furthermore, biochemical changes in blood and urine indicated the pigs were experiencing respiratory alkalosis. Minimal modelling of parameters of insulin sensitivity showed that HS pigs had a lower insulin response to the IVGTT and improved insulin sensitivity. Cinnamon had additive effects with heat stress, reflected in lowering the insulin area under curve (AUC) and elevated insulin sensitivity compared to TN. However, this apparent improvement in insulin sensitivity did not ameliorate any of the other physiological symptoms of HS.

scholarly journals Effects of cooled floor pads combined with chilled drinking water on behavior and performance of lactating sows under heat stress

2021 ◽  
Vol 99 (3) ◽  
Author(s):  
Y Zhu ◽  
L J Johnston ◽  
M H Reese ◽  
E S Buchanan ◽  
J E Tallaksen ◽  
...  
Keyword(s):  
Drinking Water ◽  
Heat Stress ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Time Budget ◽  
Video Recording ◽  
Lactating Sows ◽  
Before And After ◽  
And Performance ◽  
Drinking Frequency

Abstract This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700–1900 hours) and 23.9°C (1900–0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21–22°C) and chilled drinking water (13–15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530–1730 hours) each video-recording day. Postures (lying laterally, lying ventrally, sitting, and standing) were recorded by scanning video recordings at 5-min intervals for 24 h each video-recording day, and time budget for each posture was calculated. Rectal temperature and respiration rate were measured for all sows the day before and after farrowing, and then once weekly. Sow and litter performance was recorded. Data were analyzed using the Glimmix procedure of SAS. The cooling treatment did not affect sow behavior or litter performance. Sows in the Cool room had lower rectal temperature (P = 0.03) and lower respiration rate (P &lt; 0.001), consumed more feed (P = 0.03), tended to have reduced weight loss (P = 0.07), and backfat loss (P = 0.07) during lactation than sows in the Control room. As lactation progressed, sows increased drinking frequency (P &lt; 0.001) and time spent lying ventrally (P &lt; 0.0001), standing (P &lt; 0.001), and sitting (P &lt; 0.0001), and decreased time spent lying laterally (P &lt; 0.0001) in both Cool and Control rooms. While cooled floor pads combined with chilled drinking water did not affect sow behavior, they did alleviate heat stress partially, as indicated by decreased rectal temperature, respiration rate, weight, and backfat loss, and increased feed intake in lactating sows.

Natural Stilbene Polyphenols as Yarrowia lipolytica Cell Cytoprotectors at Heat Stress

2021 ◽  
Vol 37 (6) ◽  
pp. 14-24
Author(s):  
N.N. Gessler ◽  
E.P. Isakova ◽  
Yu.I. Deryabina
Keyword(s):  
Heat Stress ◽  
Heat Shock ◽  
Yarrowia Lipolytica ◽  
Respiration Rate ◽  
Catalase Activity ◽  
Thermal Exposure ◽  
Biologically Active ◽  
Yeast Cells ◽  
Protective Properties ◽  
Cyanide Resistance

Using the extremophilic yeast of Yarrowia lipolytica, a new model has been proposed to study the protective properties of stilbene polyphenols, namely resveratrol and pinosylvin, under heat shock. It was shown that a short-term thermal exposure of yeast cells (55 C, 25 min) led to a 40% decrease in the colony-forming ability of the population, a fivefold decrease in the respiration rate, and a growth of cyanide resistance and catalase activity, which indicated the adaptive yeast response to heat stress. Under these conditions, natural biologically active stilbenes, resveratrol and pinosylvin, at a concentration of 10 μM each increased yeast survival by 28% and 13%, respectively. In heat shock, resveratrol additionally raised catalase activity, while pinosylvin increased the cell respiration rate and decreased cyanide resistance and catalase activity. The results obtained indicate that resveratrol acts as a mild pro-oxidant inducing antioxidant protection during the adaptive response of the yeast to heat shock. Unlike resveratrol, pinosylvin increases cell survival stabilizing mitochondrial function and preserving the ATP-generating component of respiration. Yarrowia lipolytica yeast, polyphenols, stilbenoids, resveratrol, pinosylvin, cellular respiratory activity, heat shock, superoxide dismutase, catalase

scholarly journals Critical Temperature-Humidity Index Thresholds for Dry Cows in a Subtropical Climate

2021 ◽  
Vol 2 ◽  
Author(s):  
Véronique Ouellet ◽  
Izabella M. Toledo ◽  
Bethany Dado-Senn ◽  
Geoffrey E. Dahl ◽  
Jimena Laporta
Keyword(s):  
Heat Stress ◽  
Respiration Rate ◽  
Rectal Temperature ◽  
Dry Matter ◽  
Dry Matter Intake ◽  
Subtropical Climate ◽  
Dry Period ◽  
Environmental Indices ◽  
Temperature Humidity Index ◽  
Humidity Index

The effects of heat stress on dry cows are profound and significantly contribute to lower overall welfare, productivity, and profitability of the dairy sector. Although dry cows are more thermotolerant than lactating cows due to their non-lactating state, similar environmental thresholds are currently used to estimate the degree of heat strain and cooling requirements. Records of dry cow studies conducted over 5 years in Gainesville, Florida, USA were pooled and analyzed to determine environmental thresholds at which dry cows exhibit signs of heat stress in a subtropical climate. Dry-pregnant multiparous dams were actively cooled (CL; shade of a freestall barn, fans and water soakers, n = 107) or not (HT; shade only, n = 111) during the last 7 weeks of gestation, concurrent with the entire dry period. Heat stress environmental indices, including ambient temperature, relative humidity, and temperature-humidity index (THI), and animal-based indices, including respiration rate, rectal temperature and daily dry matter intake were recorded in all studies. Simple correlations were performed between temperature-humidity index and each animal-based indicator. Differences in respiration rate, rectal temperature and dry matter intake between treatments were analyzed by multiple regression. Using segmented regression, temperature-humidity thresholds for significant changes in animal-based indicators of heat stress were estimated. Stronger significant correlations were found between the temperature-humidity index and all animal-based indices measured in HT dry cows (−0.22 ≤ r ≤ 0.35) relative to CL dry cows (−0.13 ≤ r ≤ 0.19). Although exposed to similar temperature-humidity index, rectal temperature (+0.3°C; P &lt; 0.001) and respiration rate (+23 breaths/min; P &lt; 0.001) were elevated in HT dry cows compared with CL cows whereas dry matter intake (−0.4 kg of dry matter/d; P = 0.003) was reduced. Temperature-humidity index thresholds at which respiration rate and rectal temperature began to change were both determined at a THI of 77 in HT dry cows. No significant temperature-humidity threshold was detected for dry matter intake. At a practical level, our results demonstrate that dry cow respiration rate and rectal temperature increased abruptly at a THI of 77 when provided only shade and managed in a subtropical climate. Therefore, in the absence of active cooling, dry cows should be closely monitored when or before THI reaches 77 to avoid further heat-stress related impairments during the dry period and the subsequent lactation and to mitigate potential carry-over effects on the offspring.

scholarly journals 235 Effects of rapamycin during an acute heat stress exposure in growing pigs

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 117-117
Author(s):  
Edith J Mayorga ◽  
Erin A Horst ◽  
Brady M Goetz ◽  
Sonia Rodríguez-Jiménez ◽  
Megan A Abeyta ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Heat Stress ◽  
Rectal Temperature ◽  
Blood Cells ◽  
White Blood Cells ◽  
Growing Pigs ◽  
Stress Exposure ◽  
Esterified Fatty Acids ◽  
Acute Heat Stress ◽  
Ad Libitum

Abstract Objectives were to determine the effects of rapamycin on biomarkers of metabolism and inflammation during acute heat stress (HS) in growing pigs. Crossbred barrows (n=32; 63.5±0.8 BW) where blocked by BW and randomly assigned to 1 of 4 therapeutic-environmental treatments: 1) thermoneutral (TN) control (n=8; TNCtl), 2) TN and rapamycin (n=8; TNRapa), 3) HS control (n=8; HSCtl), or 4) HS and rapamycin (n=8; HSRapa). The trial consisted of 2 experimental periods (P). During P1 (10d), pigs were fed ad libitum and housed in TN conditions (21.3±0.01°C). During P2 (24h), HSCtl and HSRapa pigs were exposed to constant HS (35.5±0.1°C); while TNCtl and TNRapa remained in TN conditions. Rapamycin (0.15 mg/kg BW) was orally administered twice daily (0700 and 1800 h) during P1 and P2. HS increased rectal temperature, skin temperature, and respiration rate compared to TN counterparts (1.28°C, 8.68°C, and 87 bpm, respectively; P&lt; 0.01). Feed intake (FI) markedly decreased in HS relative to TN treatments (64%; P&lt; 0.01). Additionally, pigs exposed to HS lost BW (4 kg; P&lt; 0.01), while TN pigs gained BW (0.7 kg; P&lt; 0.01). Overall, circulating white blood cells decreased in HS compared to TN pigs (19%; P=0.01). Circulating neutrophils did not differ across treatments; however, lymphocytes, monocytes, and basophils decreased in HS relative to TN pigs (23, 33, and 38%, respectively; P≤0.07). Despite marked changes in phenotypic parameters, circulating glucose and blood urea nitrogen did not differ among treatments (P &gt;0.10). However, insulin:FI increased in HS relative to TN treatments (P=0.04). Plasma non-esterified fatty acids (NEFA) increased in HS relative to TN treatments; although this difference was driven by increased NEFA in HSCtl compared to TN and HSRapa pigs (P&lt; 0.01). In summary, pigs exposed to HS had altered phenotypic, metabolic, and leukocyte responses; however, rapamycin administration had little to no effect on any of the variables measured.

Assessment of digestible lysine requirements in lipopolysaccharide-challenged pigs

2021 ◽  
Author(s):  
Joyce Barcellos ◽  
Warley Júnior Alves ◽  
Pedro Riguetti Arnaut ◽  
Lucimauro Fonseca ◽  
Jorge Cunha Lima Muniz ◽  
...  
Keyword(s):  
Rectal Temperature ◽  
Feed Intake ◽  
Total Protein ◽  
Sampling Period ◽  
Experimental Period ◽  
N Deposition ◽  
Growing Pigs ◽  
N Balance ◽  
Model Parameters ◽  
Lps Challenge

Abstract To evaluate the effect of an E. coli lipopolysaccharide (LPS) challenge on the digestible lysine (Lys) requirement for growing pigs, a nitrogen (N) balance assay was performed. Seventy-two castrated male pigs [19 ± 1.49 kg body weight (BW)] were allocated in a 2 x 6 factorial design composed of two immune activation states (control and LPS-challenged) and 6 dietary treatments with N levels of 0.94, 1.69, 2.09, 3.04, 3.23 and 3.97% N, as fed, where Lys was limiting, with six replicates and one pig per unit. The challenge consisted of an initial LPS dose of 30 μg/kg BW via intramuscular (IM) injection and a subsequent dose of 33.6 μg/kg BW after 48 h. The experimental period lasted 11 days and was composed of a 7-day adaptation and a subsequent 4-day sampling period in which N intake (NI), N excretion (NEX) and N deposition (ND) were evaluated. Inflammatory mediators and rectal temperature were assessed during the 4-day collection period. A 3-way interaction (N levels × LPS challenge × time, P &lt; 0.05) for IgG was observed. Additionally, 2-way interactions (challenge × time, P &lt; 0.05) were verified for IgA, ceruloplasmin, transferrin, haptoglobin, α-1-acid glycoprotein, total protein, and rectal temperature; and (N levels × time, P &lt; 0.05) for transferrin, albumin, haptoglobin, total protein and rectal temperature. LPS-challenged pigs showed lower (P &lt; 0.05) feed intake. A 2-way interaction (N levels × LPS challenge, P &lt; 0.05) was observed for NI, NEX and ND, with a clear dose-response (P &lt; 0.05). LPS-challenged pigs showed lower NI and ND at 2.09% N and 1.69 to 3.97% N (P &lt; 0.05), respectively, and higher NEX at 3.23% N (P &lt; 0.05). The parameters obtained by a nonlinear model (N maintenance requirement, NMR and theoretical maximum N deposition, NDmaxT) were 152.9 and 197.1 mg/BWkg  0.75/d for NMR, and 3,524.7 and 2,077.8 mg/BWkg  0.75/d for NDmaxT, for control and LPS-challenged pigs, respectively. The estimated digestible Lys requirements were 1,994.83 and 949.16 mg/BWkg  0.75/d for control and LPS-challenged pigs, respectively. The daily digestible Lys intakes required to achieve 0.68 and 0.54 times the NRmaxT value were 18.12 and 8.62 g/d, respectively, and the optimal dietary digestible Lys concentration may change depending on the feed intake levels. Based on the derived model parameters obtained in the N balance trial with lower cost and time, it was possible to differentiate the digestible Lys requirement for swine under challenging conditions.

Modified protocols improve insulin sensitivity estimation using the minimal model

1987 ◽  
Vol 253 (6) ◽  
pp. E595-E602 ◽  
Author(s):  
Y. J. Yang ◽  
J. H. Youn ◽  
R. N. Bergman
Keyword(s):  
Standard Deviation ◽  
Insulin Sensitivity ◽  
Minimal Model ◽  
Insulin Response ◽  
Tolerance Test ◽  
Intravenous Glucose Tolerance Test ◽  
Improve Insulin Sensitivity ◽  
Intravenous Glucose ◽  
Sensitivity Estimation ◽  
Model Technique

We attempted to improve the precision of the estimation of insulin sensitivity (S1) from the minimal model technique by modifying insulin dynamics during a frequently sampled intravenous glucose tolerance test (FSIGT). Tolbutamide and somatostatin (SRIF) were used to change the insulin dynamics without directly affecting insulin sensitivity. Injection of tolbutamide (100 mg) at t = 20 min provoked an immediate secondary peak in insulin response, resulting in a greater integrated incremental insulin than the standard FSIGT. SRIF, injected at t = -1 min, delayed insulin secretion in proportion to the dose without any change in magnitude. Computer simulation was used to assess the precision of S1 estimation. Insulin dynamics from both standard and modified protocols were adjusted in magnitude, with the shape unchanged and analyzed to determine the effect of the magnitude of insulin response. Fractional standard deviation was reduced from 73% with the standard insulin profile to 23% with tolbutamide and 18% with the highest dose of SRIF. In addition, the fractional standard deviation of S1 estimates decreased exponentially with increasing magnitude of insulin response. Modified FSIGTs require a smaller insulin response than the standard protocol to achieve the same precision.

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