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Hubbard BT, LaMoia TE, Goedeke L, Gaspar RC, Galsgaard KD, Kahn M, Mason GF, Shulman GI. Q-Flux: A method to assess hepatic mitochondrial succinate dehydrogenase, methylmalonyl-CoA mutase, and glutaminase fluxes in vivo. Cell Metab 2023; 35:212-226.e4. [PMID: 36516861 PMCID: PMC9887731 DOI: 10.1016/j.cmet.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/14/2022] [Accepted: 11/21/2022] [Indexed: 12/15/2022]
Abstract
The mammalian succinate dehydrogenase (SDH) complex has recently been shown as capable of operating bidirectionally. Here, we develop a method (Q-Flux) capable of measuring absolute rates of both forward (VSDH(F)) and reverse (VSDH(R)) flux through SDH in vivo while also deconvoluting the amount of glucose derived from four discreet carbon sources in the liver. In validation studies, a mitochondrial uncoupler increased net SDH flux by >100% in awake rodents but also increased SDH cycling. During hyperglucagonemia, attenuated pyruvate cycling enhances phosphoenolpyruvate carboxykinase efficiency to drive increased gluconeogenesis, which is complemented by increased glutaminase (GLS) flux, methylmalonyl-CoA mutase (MUT) flux, and glycerol conversion to glucose. During hyperinsulinemic-euglycemic clamp, both pyruvate carboxylase and GLS are suppressed, while VSDH(R) is increased. Unstimulated MUT is a minor anaplerotic reaction but is readily induced by small amounts of propionate, which elicits glucagon-like metabolic rewiring. Taken together, Q-Flux yields a comprehensive picture of hepatic mitochondrial metabolism and should be broadly useful to researchers.
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Affiliation(s)
- Brandon T Hubbard
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Traci E LaMoia
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA
| | - Leigh Goedeke
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Rafael C Gaspar
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Katrine D Galsgaard
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Mario Kahn
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Graeme F Mason
- Department of Radiology & Biomedical Imaging, Yale School of Medicine, New Haven, CT 06510, USA; Departments of Psychiatry & Biomedical Engineering, Yale School of Medicine, New Haven, CT 06510, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, CT 06510, USA.
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Meehan DJ, Cabrita ARJ, Maia MRG, Fonseca AJM. Energy: Protein Ratio in Ruminants: Insights from the Intragastric Infusion Technique. Animals (Basel) 2021; 11:ani11092700. [PMID: 34573666 PMCID: PMC8464725 DOI: 10.3390/ani11092700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/06/2021] [Accepted: 09/10/2021] [Indexed: 12/02/2022] Open
Abstract
Simple Summary One key question that has confounded nutritional scientists for years is how the ruminant responds metabolically with respect to energy and nitrogen utilisation when no exogenous energy is consumed. Fasting metabolism studies using the intragastric infusion technique (IIT) showed this to be a glucose-deficient state characterised by elevated nitrogen excretion and heat production. However, modern feeding systems continue to adopt fasting as the basis for measuring utilisation efficiency of nutritionally balanced diets, giving rise to the false concept of greater feed utilisation below than above energy maintenance. Another IIT finding was that given the animal’s genetic capacity for protein accretion and provided a rumen undegradable protein is fed, ruminants do not catabolise amino acids as an energy source but instead retain these to attain substantial gains in tissue protein deposition, fuelled by endogenous energy reserves. This suggests that endogenous fat reserves could be used to retain body protein when feed supplies are scarce or of poor nutritive value and questions the need to use high-energy diets in the finishing pre-slaughter period. Moreover, body protein and body fat deposition were also shown to be negatively correlated, contradicting current feeding systems which assume that nitrogen retention is always negative in an underfeeding situation. Abstract Studies on energy:protein ratio in ruminants are constrained by rumen fermentation since it governs nutrient metabolism and the ratio of energy:protein yielding nutrients available for absorption. By circumventing rumen fermentation, the total intragastric infusion technique (IIT) allowed objective quantification of maintenance energy and protein requirements, volatile fatty acid utilisation efficiency, efficiency of energy utilisation for maintenance (Km) and growth (Kf) and the origin of N retention responses to independent variation of energy and protein intake. This review outlines the key IIT findings and whether they are reflected in current feeding systems with implications for different production systems worldwide. Maintenance energy requirements are similar to those derived from comparative slaughter but maintenance N requirements are significantly lower. No differences in utilisation efficiency exist between acetic, propionic and butyric acids. At low energy intakes, endogenous energy reserves are utilised to retain amino acids and fuel substantial tissue protein gains. The use of fasting metabolism to measure the utilisation of nutritionally balanced diets is questioned since it is a glucose-deficient state. Inter-species differences in glucose metabolism appear to exist, suggesting that glucose requirements may be higher in cattle than sheep. The difficulty in predicting nutrient requirements, particularly protein, with any one technique is highlighted.
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Affiliation(s)
- Denis J. Meehan
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (D.J.M.); (A.R.J.C.); (M.R.G.M.)
- UTAD, Universidade de Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal
| | - Ana R. J. Cabrita
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (D.J.M.); (A.R.J.C.); (M.R.G.M.)
| | - Margarida R. G. Maia
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (D.J.M.); (A.R.J.C.); (M.R.G.M.)
| | - António J. M. Fonseca
- REQUIMTE, LAQV, ICBAS, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira, 4050-313 Porto, Portugal; (D.J.M.); (A.R.J.C.); (M.R.G.M.)
- Correspondence:
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Ortiz R, López M, Pérez RE, Ramírez PDLP, Ordaz G. Effect of the Inclusion of Different Levels of Dietary Cactus ( Opuntia ficus-indica) on Gilts' Biochemical Parameters and Feed Intake during Lactation. Animals (Basel) 2020; 10:ani10101881. [PMID: 33076476 PMCID: PMC7602610 DOI: 10.3390/ani10101881] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 01/10/2023] Open
Abstract
Simple Summary The digestive and metabolic adaptations suffered by sows during the late gestation-lactation transition cause a decrease in the voluntary feed intake. These conditions favor a negative energy balance, forcing the body to mobilize body reserves to meet their nutritional requirements, which represents an obstacle to expressing their reproductive and productive potential. The supplementation of the sows’ diet with cactus (Opuntia ficus-indica L.) improves the feed intake in lactation due to the favorable modulation of biochemical indicators. However, the optimal addition of cactus to the diet of lactating sows is unknown. In the present study, the increase in the inclusion level of cactus did not linearly increase the feed intake in lactation. However, a linear increase in plasma insulin and osteocalcin concentrations were observed, which led to a decrease in the plasma glucose concentrations. We conclude that the inclusion level of cactus (fresh base) in the diet of lactating sows of 1.0% (with respect to the body weight of the sow) could improve the feed intake in lactation and reduce the loss of body weight of the sow at weaning. Abstract The regulation of sows’ metabolic state during the gestation-lactation transition is a requirement for a higher feed intake in lactation, an important aspect in improving animal welfare in current swine production systems. The present study aimed to evaluate the effects of the inclusion of different cactus (Opuntia ficus-indica L.) levels in the diet of gilts during late gestation and lactation on their biochemical parameters and voluntary feed intake during lactation. From day 85 of gestation until weaning, 40 gilts were divided into four groups: GNC (group with no cactus) with a basal diet (BD) only, G1C; group with 1% inclusion of cactus plus BD, G2C; group with 1.5% inclusion of cactus plus BD, and G3C; group with 2% inclusion of cactus plus BD. The dietary cactus supplementation increased the gilts’ feed intake (by 1.04 kg/day on average) during lactation and reduced their weight loss (4.3%) at weaning. The glucose concentrations were higher (range 73.0–83.9 mg/dL) in the GNC. The GNC had the highest triglyceride and cholesterol concentrations at day 100 of gestation. G3C had the highest osteocalcin concentration at day 100 of gestation. The highest feed intake and lowest glucose concentration were achieved with a cactus consumption of 1.04% in lactating gilts.
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Affiliation(s)
- Ruy Ortiz
- Faculty of Veterinary Medicine and Zootechnics, Universidad Michoacana de San Nicolás de Hidalgo, 58130 Michoacan, Mexico; (R.O.); (M.L.)
| | - Manuel López
- Faculty of Veterinary Medicine and Zootechnics, Universidad Michoacana de San Nicolás de Hidalgo, 58130 Michoacan, Mexico; (R.O.); (M.L.)
| | - Rosa E. Pérez
- Faculty of Chemical Pharmacobiology, Universidad Michoacana de San Nicolás de Hidalgo, 58130 Michoacan, Mexico
- Correspondence: ; Tel.: +52-4525294181
| | - Paola de la Paz Ramírez
- Postgraduate Student of the Faculty of Veterinary Medicine and Zootechnics, Universidad Michoacana de San Nicolás de Hidalgo, 58130 Michoacan, Mexico;
| | - Gerardo Ordaz
- National Center of Disciplinary Research in Animal Physiology and Genetics, INIFAP, 76280 Queretaro, Mexico;
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Kalyesubula M, Mopuri R, Rosov A, Alon T, Edery N, Moallem U, Dvir H. Hyperglycemia-stimulating diet induces liver steatosis in sheep. Sci Rep 2020; 10:12189. [PMID: 32699301 PMCID: PMC7376193 DOI: 10.1038/s41598-020-68909-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/02/2020] [Indexed: 01/15/2023] Open
Abstract
Hepatic steatosis is strongly associated with chronic liver disease and systemic metabolic disorder. Adipose lipolysis is a recognized principal source of intrahepatic fat in various metabolic disorders, including non-alcoholic fatty liver disease. We hypothesized that, in the premorbid state, hepatic de novo lipogenesis (DNL) driven by excess carbohydrates abundance might play a more significant role. We employed a novel nutritional model in sheep of two distinct carbohydrates abundances. During 4 months of the dietary treatment, lambs were monitored for metabolic and terminal liver parameters. Lambs grown on the high-calorie (HC) diet were consistently more hyperglycemic and hyperinsulinemic than lambs grown on the lower-calorie (LC) diet (P < 0.0001). As a result, the HC lambs developed systemic- (HOMA-IR of 7.3 vs. 3.1; P < 0.0001), and adipose- (ADIPO-IR of 342.7 vs. 74.4; P < 0.0001) insulin resistance, significant adiposity (P < 0.0001), and higher plasma triglycerides (P < 0.05). Circulating leukocytes in the HC lambs had higher mRNA expression levels of the proinflammatory markers CCL2 (P < 0.01) and TNF-alpha (P < 0.04), and IL1B trended higher (P < 0.1). Remarkably, lambs on the HC diet developed substantial liver steatosis (mean fat content of 8.1 vs. 5.3% in the LC group; P < 0.0001) with a higher histological steatosis score (2.1 vs. 0.4; P < 0.0002). Hepatic steatosis was most-strongly associated with blood glucose and insulin levels but negatively correlated with circulating fatty acids-indicating a more significant contribution from hepatic DNL than from adipose lipolysis. Sheep may prove an attractive large-animal model of fatty liver and metabolic comorbidities resulting from excess carbohydrate-based energy early in life.
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Affiliation(s)
- Mugagga Kalyesubula
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel
- Department of Animal Science, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Ramgopal Mopuri
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel
| | - Alexander Rosov
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel
| | - Tamir Alon
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel
- Department of Animal Science, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Nir Edery
- Pathology Laboratory, Kimron Veterinary Institute, Veterinary Services, Rishon LeZion, Israel
| | - Uzi Moallem
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel
| | - Hay Dvir
- Institute of Animal Science, Volcani Center - ARO, Rishon LeZion, Israel.
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Lourenco JM, Kieran TJ, Seidel DS, Glenn TC, da Silveira MF, Callaway TR, Stewart RL. Comparison of the ruminal and fecal microbiotas in beef calves supplemented or not with concentrate. PLoS One 2020; 15:e0231533. [PMID: 32282837 PMCID: PMC7153887 DOI: 10.1371/journal.pone.0231533] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 03/25/2020] [Indexed: 01/02/2023] Open
Abstract
Most of the research efforts involving the bovine gastrointestinal microbiota have focused on cattle’s forestomach, particularly the rumen, so information concerning the bovine fecal microbiota is more scarce, especially in young beef cattle. The present study was performed to evaluate the ruminal and fecal microbiotas of beef calves as they reached the end of their nursing phase. A total of 18 Angus cow/calf pairs were selected and assigned to one of two treatment groups for the last 92 days of the calves’ nursing period, as follows: 1) calves were supplemented with concentrate in a creep feeding system; or 2) control group with no supplementation of calves. After 92 days, ruminal and fecal samples were individually obtained from calves in both groups, and their microbiotas were evaluated using 16S rRNA gene sequencing. Ruminal samples were predominated by Prevotella (18 to 23% of the total bacterial abundance), regardless if calves received supplementation or not; however, in the feces, Prevotella was only the seventh most abundant genus (0.6 to 2.1% of total bacterial abundance). Both the rumen (P = 0.01) and the feces (P = 0.05) of calves that received supplementation had greater abundance of Firmicutes. In addition, calves that were supplemented had lower abundance of Fibrobacteres (P = 0.03) in their rumens. Regardless if the calves were supplemented or not, Faith’s Phylogenetic Diversity index (P ≤ 0.007) and total concentration of short chain fatty acids (P < 0.001) were both greater in the rumen than in the feces of calves. In summary, the ruminal and fecal microbiotas of weanling beef calves were considerably distinct. Additionally, supplementation with creep feed caused some significant changes in the composition of the gastrointestinal microbiota of the calves, especially in the rumen, where supplementation caused an increase in Firmicutes and a decrease in abundance of Fibrobacteres.
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Affiliation(s)
- Jeferson M. Lourenco
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States of America
- * E-mail:
| | - Troy J. Kieran
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States of America
| | - Darren S. Seidel
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States of America
| | - Travis C. Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States of America
| | | | - Todd R. Callaway
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States of America
| | - R. Lawton Stewart
- Department of Animal and Dairy Science, University of Georgia, Athens, GA, United States of America
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Fassah DM, Jeong JY, Baik M. Hepatic transcriptional changes in critical genes for gluconeogenesis following castration of bulls. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2018; 31:537-547. [PMID: 29502393 PMCID: PMC5838326 DOI: 10.5713/ajas.17.0875] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/22/2018] [Accepted: 02/05/2018] [Indexed: 02/07/2023]
Abstract
Objective This study was performed to understand transcriptional changes in the genes involved in gluconeogenesis and glycolysis pathways following castration of bulls. Methods Twenty Korean bulls were weaned at average 3 months of age, and castrated at 6 months. Liver tissues were collected from bulls (n = 10) and steers (n = 10) of Korean cattle, and hepatic gene expression levels were measured using quantitative real-time polymerase chain reaction. We examined hepatic transcription levels of genes encoding enzymes for irreversible reactions in both gluconeogenesis and glycolysis as well as genes encoding enzymes for the utilization of several glucogenic substrates. Correlations between hepatic gene expression and carcass characteristics were performed to understand their associations. Results Castration increased the mRNA (3.6 fold; p<0.01) and protein levels (1.4 fold; p< 0.05) of pyruvate carboxylase and mitochondrial phosphoenolpyruvate carboxykinase genes (1.7 fold; p<0.05). Hepatic mRNA levels of genes encoding the glycolysis enzymes were not changed by castration. Castration increased mRNA levels of both lactate dehydrogenase A (1.5 fold; p<0.05) and lactate dehydrogenase B (2.2 fold; p<0.01) genes for lactate utilization. Castration increased mRNA levels of glycerol kinase (2.7 fold; p<0.05) and glycerol-3-phosphate dehydrogenase 1 (1.5 fold; p<0.05) genes for glycerol utilization. Castration also increased mRNA levels of propionyl-CoA carboxylase beta (mitochondrial) (3.5 fold; p<0.01) and acyl-CoA synthetase short chain family member 3 (1.3 fold; p = 0.06) genes for propionate incorporation. Conclusion Castration increases transcription levels of critical genes coding for enzymes involved in irreversible gluconeogenesis reactions from pyruvate to glucose and enzymes responsible for incorporation of glucogenic substrates including lactate, glycerol, and propionate. Hepatic gluconeogenic gene expression levels were associated with intramuscular fat deposition.
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Affiliation(s)
- Dilla Mareistia Fassah
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea
| | - Jin Young Jeong
- Animal Nutrition & Physiology Team, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Myunggi Baik
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.,Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Korea
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Nutritional regulation of the anabolic fate of amino acids within the liver in mammals: concepts arising from in vivo studies. Nutr Res Rev 2016; 28:22-41. [PMID: 26156215 DOI: 10.1017/s0954422415000013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
At the crossroad between nutrient supply and requirements, the liver plays a central role in partitioning nitrogenous nutrients among tissues. The present review examines the utilisation of amino acids (AA) within the liver in various physiopathological states in mammals and how the fates of AA are regulated. AA uptake by the liver is generally driven by the net portal appearance of AA. This coordination is lost when demands by peripheral tissues is important (rapid growth or lactation), or when certain metabolic pathways within the liver become a priority (synthesis of acute-phase proteins). Data obtained in various species have shown that oxidation of AA and export protein synthesis usually responds to nutrient supply. Gluconeogenesis from AA is less dependent on hepatic delivery and the nature of nutrients supplied, and hormones like insulin are involved in the regulatory processes. Gluconeogenesis is regulated by nutritional factors very differently between mammals (glucose absorbed from the diet is important in single-stomached animals, while in carnivores, glucose from endogenous origin is key). The underlying mechanisms explaining how the liver adapts its AA utilisation to the body requirements are complex. The highly adaptable hepatic metabolism must be capable to deal with the various nutritional/physiological challenges that mammals have to face to maintain homeostasis. Whereas the liver responds generally to nutritional parameters in various physiological states occurring throughout life, other complex signalling pathways at systemic and tissue level (hormones, cytokines, nutrients, etc.) are involved additionally in specific physiological/nutritional states to prioritise certain metabolic pathways (pathological states or when nutritional requirements are uncovered).
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Zhang Q, Koser SL, Bequette BJ, Donkin SS. Effect of propionate on mRNA expression of key genes for gluconeogenesis in liver of dairy cattle. J Dairy Sci 2015; 98:8698-709. [DOI: 10.3168/jds.2015-9590] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/28/2015] [Indexed: 11/19/2022]
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McCarthy MM, Yasui T, Ryan CM, Pelton SH, Mechor GD, Overton TR. Metabolism of early-lactation dairy cows as affected by dietary starch and monensin supplementation. J Dairy Sci 2015; 98:3351-65. [PMID: 25771049 DOI: 10.3168/jds.2014-8821] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 02/05/2015] [Indexed: 01/05/2023]
Abstract
The objective of this study was to evaluate the effect of dietary starch content and monensin (MON) on metabolism of dairy cows during early lactation. Before parturition, primiparous (n=21) and multiparous (n=49) Holstein cows were fed a common controlled-energy close-up diet with a daily topdress of either 0 or 400mg/d monensin. From d 1 to 21 postpartum, cows were fed a high-starch (HS; 26.2% starch, 34.3% neutral detergent fiber, 22.7% acid detergent fiber, 15.5% crude protein) or low-starch (LS; 21.5% starch, 36.9% neutral detergent fiber, 25.2% acid detergent fiber, 15.4% crude protein) total mixed ration with a daily topdress of either 0mg/d monensin (CON) or 450mg/d monensin (MON), continuing with prepartum topdress assignment. From d 22 through 63 postpartum, all cows were fed HS and continued with the assigned topdress treatment until d 63. Cows fed HS had higher plasma glucose and insulin and lower nonesterified fatty acids (NEFA) than cows fed LS during d 1 to 21 postpartum. Cows fed LS had elevated early-lactation β-hydroxybutyrate (BHBA) compared with cows fed HS. Cows fed HS had greater insulin resistance and increased plasma haptoglobin in the early lactation period. There was no effect of MON on postpartum plasma NEFA. Cows fed MON had higher plasma glucose compared with CON cows, which was driven by a MON × parity interaction in which primiparous cows fed MON had greater plasma glucose concentrations than cows fed CON. Cows fed MON had lower plasma BHBA compared with CON, which was contributed to by a MON × parity interaction in which primiparous cows fed MON had lower BHBA concentrations than CON. Starch treatment had no effect on overall liver triglyceride content. Primiparous cows fed MON had increased liver triglyceride content compared with CON primiparous cows, and multiparous cows fed MON had decreased liver triglyceride content compared with CON cows. Multiparous cows fed LS with MON had higher liver glycogen content than multiparous cows fed the LS without MON, with no effect of MON treatment for multiparous cows fed HS. There was no effect of starch or MON treatment on liver capacity to oxidize propionate to CO2, and effects of starch on gluconeogenesis were not significant. Cows fed MON tended to have greater capacity to convert propionate to glucose than CON. Supplementation with MON increased the ratio of glucose to CO2, which indicated that cows fed MON had a greater propensity to convert propionate to glucose. Overall, cows fed more propiogenic diets in early lactation (high starch or monensin) exhibited improved energy metabolism during early lactation.
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Affiliation(s)
- M M McCarthy
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - T Yasui
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - C M Ryan
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - S H Pelton
- Department of Animal Science, Cornell University, Ithaca, NY 14853
| | - G D Mechor
- Elanco Animal Health, Greenfield, IN 46140
| | - T R Overton
- Department of Animal Science, Cornell University, Ithaca, NY 14853.
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Empirical prediction of net splanchnic release of ketogenic nutrients, acetate, butyrate and β-hydroxybutyrate in ruminants: a meta-analysis. Animal 2015; 9:449-63. [DOI: 10.1017/s1751731114002638] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Nikkhah A. Review: Ruminant feed intake regulation evolution: chronophysiological rhythms perspectives. BIOL RHYTHM RES 2014. [DOI: 10.1080/09291016.2013.874215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Cantalapiedra-Hijar G, Lemosquet S, Rodriguez-Lopez JM, Messad F, Ortigues-Marty I. Diets rich in starch increase the posthepatic availability of amino acids in dairy cows fed diets at low and normal protein levels. J Dairy Sci 2014; 97:5151-66. [PMID: 24931534 DOI: 10.3168/jds.2014-8019] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 04/25/2014] [Indexed: 11/19/2022]
Abstract
Five mid-lactation multicatheterized Jersey cows were used in a 4×4 Latin square design to investigate whether the increase in milk N yield associated with diets rich in starch versus fiber could originate from changes in the splanchnic AA metabolism and if these changes depended upon the dietary crude protein (CP) content. Four isoenergetic diets were formulated to provide 2 different carbohydrate compositions [diets rich in starch (350g of starch and 310g of neutral detergent fiber/kg of dry matter) versus rich in fiber (45g of starch and 460g of neutral detergent fiber/kg of dry matter)] crossed by 2 different CP contents (12.0 vs. 16.5% CP). At the end of each treatment period, 6 hourly blood samples were collected from the portal and hepatic veins as well as the mesenteric artery to determine net nutrient fluxes across the portal-drained viscera (PDV), liver, and total splanchnic tissues. Dry matter and calculated energy intake as well as total absorbed energy were similar across treatments. However, the net portal appearance (NPA) of acetate, total volatile fatty acids, and β-hydroxybutyrate were higher with diets rich in fiber versus starch, whereas that of oxygen, glucose, butyrate, and insulin were lower. Concomitant to these changes, the percentage of N intake recovered as total AA (TAA) in the portal vein was lower for diets rich in fiber versus starch (42.3 vs. 51.4%, respectively), without, however, any difference observed in the NPA of the main AA used as energy fuels by the PDV (Glu, Gln, and Asp). Despite a higher NPA of TAA with starch versus fiber diets, no differences in the net hepatic flux of TAA, essential and nonessential AA were observed, resulting in a higher (+22%) net splanchnic release of AA and, hence, a greater (+7%) milk N yield. The net hepatic flux and hepatic fractional removal of none of the individual AA was affected as the main carbohydrate changed from fiber to starch, except for Gly and Lys, which were higher for the latter. After correcting for differences in NPA of TAA, the net hepatic uptake of TAA tended to be lower with starch versus fiber diets. The higher transfer of N from feed to milk with diets rich in starch is not the consequence of a direct sparing AA effect of glucogenic diets but rather the result of lower energy requirements by the PDV along with a higher microbial N flow to the duodenum. A better AA use by peripheral tissues with starch versus fiber diets was also hypothesized but more studies are warranted to clarify this issue.
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Affiliation(s)
- G Cantalapiedra-Hijar
- Institut National de la Recherche Agronomique, UMR 1213 INRA-VetAgroSup, Unité Mixte de Recherches sur les Herbivores, 63122 St Genès Champanelle, France.
| | - S Lemosquet
- INRA, UMR 1348 PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348 PEGASE, F-35000 Rennes, France
| | - J M Rodriguez-Lopez
- Institut National de la Recherche Agronomique, UMR 1213 INRA-VetAgroSup, Unité Mixte de Recherches sur les Herbivores, 63122 St Genès Champanelle, France
| | - F Messad
- Institut National de la Recherche Agronomique, UMR 1213 INRA-VetAgroSup, Unité Mixte de Recherches sur les Herbivores, 63122 St Genès Champanelle, France
| | - I Ortigues-Marty
- Institut National de la Recherche Agronomique, UMR 1213 INRA-VetAgroSup, Unité Mixte de Recherches sur les Herbivores, 63122 St Genès Champanelle, France
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Brown W, Allen M. Effects of intrajugular glucose infusion on feed intake, milk yield, and metabolic responses of early postpartum cows fed diets varying in protein and starch concentration. J Dairy Sci 2013; 96:7132-7142. [DOI: 10.3168/jds.2013-6636] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 07/13/2013] [Indexed: 12/23/2022]
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14
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Abstract
Glucose is the molecule that drives milk production, and insulin plays a pivotal role in the glucose metabolism of dairy cows. The effect of insulin on the glucose metabolism is regulated by the secretion of insulin by the pancreas and the insulin sensitivity of the skeletal muscles, the adipose tissue, and the liver. Insulin resistance may develop as part of physiologic (pregnancy and lactation) and pathologic processes, which may manifest as decreased insulin sensitivity or decreased insulin responsiveness. A good knowledge of the normal physiology of insulin is needed to measure the in vivo insulin resistance of dairy cows.
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15
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Nikkhah A. Chronophysiology of ruminant feeding behavior and metabolism: an evolutionary review. BIOL RHYTHM RES 2013. [DOI: 10.1080/09291016.2012.656437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Al-Trad B, Wittek T, Penner GB, Reisberg K, Gäbel G, Fürll M, Aschenbach JR. Expression and activity of key hepatic gluconeogenesis enzymes in response to increasing intravenous infusions of glucose in dairy cows. J Anim Sci 2010; 88:2998-3008. [PMID: 20495114 DOI: 10.2527/jas.2009-2463] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The present study aimed at investigating whether increasing concentrations of glucose supply have a depressive effect on the mRNA abundance and activity of key gluconeogenic enzymes in dairy cows. Twelve Holstein-Friesian dairy cows in mid-lactation were intravenously infused with saline (SI; n = 6) or a 40% glucose solution (GI; n = 6). For GI cows, the infusion dose increased by 1.25%/d relative to the initial NE(l) requirement until a maximum dose equating to surplus 30% NE(l) was reached on d 24. Cows receiving SI received an equivalent volume of 0.9% saline solution. Blood samples were taken every 2 d, and liver biopsies were collected every 8 d. A treatment x quadratic dose interaction (P < 0.01) was observed for the concentration of plasma glucose and serum insulin. The interactions were due to positive quadratic responses of the concentrations of glucose and insulin for GI cows, whereas the concentrations of glucose and insulin did not change over time for SI cows. The concentration of beta-hydroxybutyric acid (BHBA) and serum urea nitrogen (BUN) responded in a treatment x quadratic dose manner, such that greater decreases (P < 0.01) in BHBA and BUN concentrations were observed for cows receiving GI than SI as the dosage increased. Serum NEFA concentration tended to follow a similar pattern as serum BHBA and BUN; however, the interaction was not significant (P = 0.07). The mRNA abundance of gluconeogenesis enzymes followed a linear treatment x dose interaction (P < 0.05) for only pyruvate carboxylase (PC), which was paralleled by a trend for a linear treatment x dose interaction (P = 0.13) for PC enzyme activity. The least PC expression and activity were observed at the largest glucose dosage. The activity, but not mRNA abundance, of fructose 1,6-bisphosphatase (FBPase) showed treatment x quadratic dose interactions (P < 0.05) with decreasing activity at increasing glucose dose. Activities and expression of phosphoenolpyruvate carboxykinase and glucose 6-phosphatase were not affected (P > 0.25) by treatment. In conclusion, hepatic gluconeogenic enzymes are only moderately affected by slowly increasing glucose supply, including a translational or posttranslational downregulation of FBPase activity and a decrease in the mRNA abundance of PC with possible consequences for PC enzyme activity.
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Affiliation(s)
- B Al-Trad
- Institute of Physiology and Pathophysiology, University of Veterinary Medicine Vienna, 1210 Vienna, Austria
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17
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Fujita T, Majima H, Itoh T, Sano H. Combined effect of salinomycin and feeding on whole body glucose kinetics in sheep fed a high-concentrate diet. ACTA ACUST UNITED AC 2006; 46:503-14. [PMID: 17107640 DOI: 10.1051/rnd:2006035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The aim of this study was to investigate the effects of salinomycin (SL) and feeding on whole body glucose kinetics in sheep fed a high-concentrate diet (25% orchardgrass hay and 75% commercial concentrate). Four adult sheep were fed the diet with or without 20 mg x kg(-1) diet of SL once daily for each 3 wk. The rates of glucose entry and utilization were determined before and during 3 h after feeding using a [ (13)C(6)] glucose dilution approach. Ruminal characteristics and concentrations of blood volatile fatty acids (VFA) and plasma glucose and insulin were also measured. Metabolizable energy intake was unaffected (P = 0.22) with SL. Salinomycin decreased (P = 0.06) the ratio of acetate to propionate in rumen fluid. Salinomycin increased (P = 0.01) both rates of entry and utilization of glucose, but did not affect (P > 0.10) concentrations of blood VFA or plasma glucose or insulin. Feeding caused gradual increases in concentrations of blood acetate (P < 0.01) and propionate (P = 0.01), a transient increase in plasma insulin concentration (P = 0.05), a transient decrease in plasma glucose concentration (P < 0.01), and persistent increases in both rates of glucose entry (P < 0.01) and utilization (P < 0.01). No SL x feeding interaction was observed (P > 0.10) on any measurements. We conclude that SL and feeding would have an additive effect on both rates of glucose entry and utilization without modifications with SL to feeding responses of peripheral concentrations of blood VFA, plasma glucose and insulin.
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Affiliation(s)
- Tadahisa Fujita
- Department of Agro-bioscience, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan
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18
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Waldron MR, Kulick AE, Bell AW, Overton TR. Acute Experimental Mastitis Is Not Causal Toward the Development of Energy-Related Metabolic Disorders in Early Postpartum Dairy Cows. J Dairy Sci 2006; 89:596-610. [PMID: 16428629 DOI: 10.3168/jds.s0022-0302(06)72123-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Twenty Holstein cows in early lactation (7 d in milk) were administered 100 microg of Escherichia coli lipopolysaccharide (LPS) dissolved in 10 mL of sterile 0.9% NaCl saline (treatment; TRT) or 10 mL of sterile saline (control) into both right mammary quarters to test the hypothesis that acute experimental mastitis would have negative impacts on aspects of energy metabolism that might lead to the development of metabolic disorders. A primed continuous intravenous infusion (14-micromol/kg of BW priming dose; 11.5-micromol/kg of BW per h continuous infusion) of 6,6-dideuterated glucose was used to determine pre- and posttreatment glucose kinetics using steady-state tracer methodologies. The LPS-treated cows displayed productive, clinical, and physiological signs of moderate to severe inflammation; control cows displayed no signs of immune activation. Pretreatment glucose rates of appearance (Ra) into plasma were similar (715 and 662 +/- 33 mmol/h for TRT and control, respectively) between treatment groups. Intramammary LPS infusion into TRT cows resulted in increased glucose Ra relative to control cows (mean glucose Ra from 150 through 270 min after intramammary infusion were 815 and 674 +/- 21 mmol/h for TRT and control cows, respectively). Furthermore, plasma concentrations of glucose increased, whereas plasma nonesterified fatty acids, glycerol, and beta-hydroxybutyrate concentrations decreased, in TRT relative to control cows. Interestingly, plasma insulin concentration increased dramatically in TRT cows and occurred prior to the small increase in plasma glucose concentration. Although these results only represent the early stages of inflammation, they are not consistent with a causal relationship between mastitis and energy-related metabolic disorders and instead suggest a coordinated protective effect by the immune system on metabolism during the early stages of mammary insult.
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Affiliation(s)
- M R Waldron
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
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19
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Patton RS, Sorenson CE, Hippen AR. Effects of Dietary Glucogenic Precursors and Fat on Feed Intake and Carbohydrate Status of Transition Dairy Cows. J Dairy Sci 2004; 87:2122-9. [PMID: 15328225 DOI: 10.3168/jds.s0022-0302(04)70031-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Twenty-four multiparous Holstein cows were used to determine the effects of dietary fat and glucose precursors on energy status and lactation. The treatment group (T) received 409 g/d (DM basis) of a combination of calcium salts of fatty acids, calcium propionate, and propylene glycol. The control group (C) received 409 g/d of a mixture of calcium salts of fatty acids and ground barley from 14 +/- 0.9 g/d before until 21 d after calving. Dry matter intake was greater (16.1 vs. 13.6 +/- 1.3 kg/d) for T than C during the last week prepartum and did not decrease for T from the previous week, whereas, in C, DM intakes decreased by 3.2 kg/d. Production of milk and milk fat did not differ. There was a tendency for lower protein and increased lactose concentrations in milk from T cows. Milk fat percentage was lower in T at d 7 (5.5 vs. 6.4 +/- 0.5%) and 28 (4.4 vs. 5.5 +/- 0.5%) of lactation. Liver lipid content was numerically lower (7.9 vs. 9.2 +/- 0.9%) and glycogen content was significantly higher (2.4 vs. 2.0 +/- 0.1%) in T vs. C cows on d 7 of lactation. Concentrations of nonesterified fatty acids were lower in blood of T cows on d 2 and 7 of lactation. Over all time points, blood glucose concentrations were higher in T cows pre- (70.75 vs. 62.1 +/- 1.3 mg/dL) and postpartum (60.1 vs. 56.2 +/- 1.1 mg/dL). Insulin concentrations in blood were greater for T (397 vs. 314 +/- 48 pg/mL) both pre- and postpartum. Feeding glucose precursors in combination with rumen inert lipids, compared with feeding barley in combination with the lipids for 2 wk before parturition and 3 wk postpartum helped avoid prepartum feed intake depression and increased blood glucose and insulin and decreased blood NEFA.
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20
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Velez JC, Donkin SS. Bovine Somatotropin Increases Hepatic Phosphoenolpyruvate Carboxykinase mRNA in Lactating Dairy Cows,. J Dairy Sci 2004; 87:1325-35. [PMID: 15290980 DOI: 10.3168/jds.s0022-0302(04)73282-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Somatotropin (ST) increases milk production and through coordinated changes in hepatic glucose synthesis and amino acid metabolism in dairy cows. The objective of this study was to determine the effects of ST on hepatic mRNA expression for phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate carboxylase (PC), enzymes that are critical to the synthesis of glucose in liver and hepatic mRNA expression for carbamylphosphate synthetase I (CPS-I), argininosuccinate synthetase (AS), and ornithine transcarbamylase (OTC), critical enzymes of the urea cycle. Eighteen cows were randomly allocated to 2 treatment groups and received either recombinant bovine ST (Posilac; Monsanto, St. Louis, MO) or saline injections at 14-d intervals during a 42-d period. Expression of mRNA was determined using Northern blot analysis. Nuclei, isolated from liver biopsy samples, were used to determine effects of ST on transcription rate of PEPCK. Milk production was increased with ST (37.3 vs. 35.1+/-0.6 kg/ d). Plasma NEFA was increased with ST (299 vs. 156+/-34 microM). There were no differences in the expression of CPS-I, AS, and OTC mRNA with ST. Expression of PEPCK and IGF-I mRNA were increased with ST but PC mRNA was unchanged. The data indicate increased PEPCK mRNA in cows given ST and indicates a greater capacity for gluconeogenesis from gluconeogenic precursors that form oxaloacetate. The effects of ST to elevate PEPCK mRNA expression require chronic administration and involve increased transcription of the PEPCK gene.
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Affiliation(s)
- J C Velez
- Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
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21
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Drackley JK, Overton TR, Douglas GN. Adaptations of Glucose and Long-Chain Fatty Acid Metabolism in Liver of Dairy Cows during the Periparturient Period. J Dairy Sci 2001. [DOI: 10.3168/jds.s0022-0302(01)70204-4] [Citation(s) in RCA: 353] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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22
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Strang BD, Bertics SJ, Grummer RR, Armentano LE. Effect of long-chain fatty acids on triglyceride accumulation, gluconeogenesis, and ureagenesis in bovine hepatocytes. J Dairy Sci 1998; 81:728-39. [PMID: 9565876 DOI: 10.3168/jds.s0022-0302(98)75629-2] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A relationship between increased lipid concentration in the liver and reduced hepatic function has been suggested; however, there is little direct evidence of change in specific hepatic functions. Hepatocytes were obtained from ruminating calves and were incubated as monolayers for 36 h. The media contained a mixture of nonesterified fatty acids (NEFA) at 0, 0.5, 1.0, and 1.5 mM NEFA with molar proportions of 0.435 oleate, 0.319 palmitate, 0.144 stearate, 0.049 linoleate, and 0.053 palmitoleate. Ureagenesis or gluconeogenesis was measured from 48 to 51 h after plating using hepatocytes that had only previous (12 to 48 h), only concurrent (48 to 51 h), or previous and concurrent (12 to 51 h) exposure to NEFA. A previous 36-h exposure to NEFA caused cell triglyceride accumulation, yielding triglyceride concentrations that corresponded with liver that is clinically described as normal to moderately fatty. Previous, prolonged exposure to NEFA reduced ureagenesis and increased gluconeogenesis. Concurrent exposure to NEFA did not significantly affect gluconeogenesis or ureagenesis and did not alter the residual effect of prolonged incubation with NEFA. Reduced ureagenesis was related to increased cell triglyceride accumulation independently of other direct NEFA effects. Decreased ureagenic capacity may play a role in the morbidity associated with periparturient fatty liver in dairy cows.
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Affiliation(s)
- B D Strang
- Department of Dairy Science, University of Wisconsin, Madison 53706, USA
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23
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Eisemann JH, Bristol DG. Change in insulin sensitivity or responsiveness is not a major component of the mechanism of action of ractopamine in beef steers. J Nutr 1998; 128:505-11. [PMID: 9482756 DOI: 10.1093/jn/128.3.505] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Our objective was to determine whether the beta-adrenergic agonist ractopamine altered sensitivity or responsiveness to insulin. We used the hyperinsulinemic, euglycemic clamp approach in five multicatheterized beef steers to evaluate insulin sensitivity (ED50) and responsiveness (Rmax or Rmin) during control or ractopamine feeding (80 mg/kg feed). Steers had blood vessel catheters and ultrasound flow probes that allowed measurement of net uptake and release of glucose and insulin by portal-drained viscera (PDV), liver and hindlimb. Steers ate meals of equal size every 2 h. Steers were fed at 1.8 times calculated maintenance energy. The design was a single reversal. Two rates of insulin infusion followed a base-line period on each of three sample days. Insulin was infused into a mesenteric vein at 10, 20, 40, 80, 160 and 320 mU/(h.kg body weight). During the base-line period, arterial concentrations of glucose, oxygen, nonesterified fatty acids and insulin were not different between control and ractopamine feeding. Arterial urea was lower during ractopamine than during control feeding (5.02 vs. 6.20 mmol/L, respectively, P < 0.01). Net release of glucose by liver and net uptake of glucose by the hindlimb were not affected by treatment. Similarly, net release of insulin by PDV and net uptake of insulin by liver were not affected by treatment. The Rmax and ED50 for steady-state glucose infusion rate, total glucose entry, hepatic glucose production and hindlimb glucose uptake did not differ between treatments. There was a trend for a lower ED50 in hindlimb with ractopamine treatment (P < 0.13). These data do not support a change in sensitivity or responsiveness of tissues to insulin as a major component of the mechanism of action of ractopamine.
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Affiliation(s)
- J H Eisemann
- Departments of Animal Science, North Carolina State University, Raleigh, NC 27695, USA
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24
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Abstract
Increased glucose requirements of the gravid uterus during late pregnancy and even greater requirements of the lactating mammary glands necessitate major adjustments in glucose production and utilization in maternal liver, adipose tissue, skeletal muscle, and other tissues. In ruminants, which at all times rely principally on hepatic gluconeogenesis for their glucose supply, hepatic glucose synthesis during late pregnancy and early lactation is increased to accommodate uterine or mammary demands even when the supply of dietary substrate is inadequate. At the same time, glucose utilization by adipose tissue and muscle is reduced. In pregnant animals, these responses are exaggerated by moderate undernutrition and are mediated by reduced tissue sensitivity and responsiveness to insulin, associated with decreased tissue expression of the insulin-responsive facilitative glucose transporter, GLUT4. Peripheral tissue responses to insulin remain severely attenuated during early lactation but recover as the animal progresses through mid lactation. Specific homeorhetic effectors of decreased insulin-mediated glucose metabolism during late pregnancy have yet to be conclusively identified. In contrast, somatotropin is almost certainly a predominant homeorhetic influence during lactation because its exogenous administration causes specific changes in glucose metabolism (and many other functions) of various nonmammary tissues which faithfully mimic normal adaptations to early lactation.
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Affiliation(s)
- A W Bell
- Department of Animal Science, Cornell University, Ithaca, New York 14853-4801, USA.
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25
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Gaynor PJ, Waldo DR, Capuco AV, Erdman RA, Douglass LW, Teter BB. Milk fat depression, the glucogenic theory, and trans-C18:1 fatty acids. J Dairy Sci 1995; 78:2008-15. [PMID: 8550910 DOI: 10.3168/jds.s0022-0302(95)76826-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Metabolic and endocrinological characteristics were compared for cows that differed in the extent of milk fat depression. Forty-one multiparous Holstein cows were fed control (40% concentrate and 60% forage) and high concentrate (80% concentrate and 20% forage) diets in a doubale-reversal design. Cows showing one or more percentage units of depression in milk fat were arbitrarily classified as responders (n = 26); those remaining were classified as nonresponders (n = 15). Compared with nonresponders, responders had greater increases in DMI, estimated NEL intake and balance, BW, milk yield, protein and lactose yields in milk, weight percentage of trans-C18:1 fatty acids in milk, and concentrations of triiodothyronine and thyroxine in serum when switched from the control diet to the 80% concentrate diet. Lack of an increase in concentrations of glucose and insulin in serum of cows with the greatest decline in percentage of milk fat casts doubt on the ability of the glucogenic theory to explain milk fat depression completely.
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Affiliation(s)
- P J Gaynor
- Department of Animal Science, University of Maryland, College Park 20742, USA
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26
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Danfaer A, Tetens V, Agergaard N. Review and an experimental study on the physiological and quantitative aspects of gluconeogenesis in lactating ruminants. Comp Biochem Physiol B Biochem Mol Biol 1995; 111:201-10. [PMID: 7599986 DOI: 10.1016/0305-0491(94)00242-m] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A short review describes quantitative aspects of glucose metabolism in lactating ruminants, including the contribution of different substrates to glucose synthesis as affected by nutritional and hormonal regulation. Gluconeogenesis from propionate (the major gluconeogenic substrate in the fed state) is mainly regulated by feed intake and increased propionate availability and is less affected by insulin and glucagon. Quantitative estimates of amino acid contribution to glucose synthesis are highly variable (from 2 to 40% of glucose flux), but no conclusive data exist by which this large variation can be explained. An experimental model is described by which nutrient exchanges across the liver as well as the contribution of different substrates to glucose synthesis can be quantitated. The novel approach is continuous infusion of differently labelled (3H and 14C) gluconeogenic substrates into multi-catheterized goats. Results are reported from a preliminary experiment using this model. A goat in mid-lactation was fed hay ad libitum, and the experimental treatments were continuous infusion into a mesenteric vein of either sodium propionate or a complete mixture of amino acids. Measurements were nutrient exchanges across portal-drained viscera and liver, whole body glucose flux rate, and hepatic gluconeogenesis from propionate, lactate and glycerol. Glucose synthesis from amino acids was estimated by difference. Net portal appearance and hepatic uptake of propionate and of amino acids were increased by propionate and amino acid infusions, respectively. Glucose flux rate and hepatic glucose output were not affected by treatments. With propionate infusion, the proportions of liver glucose derived from propionate and amino acids were 62 and 19%, respectively. With amino acid infusion, the corresponding figures were 24 and 36%. Glucagon concentration in portal blood plasma was 2.7 times higher on the amino acid than on the propionate treatment. It is concluded that the hepatic metabolism of propionate and glucogenic amino acids into glucose synthesis is regulated to a great extent by the availability of these substrates, and that glucagon may be involved in this regulation. It is further concluded that the described experimental approach is suitable for investigations of nutrient absorption and hepatic gluconeogenesis.
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Affiliation(s)
- A Danfaer
- Department of Animal Physiology and Biochemistry, Foulum Research Centre, Tjele, Denmark
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27
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28
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Huhtanen P, Miettinen H, Ylinen M. Effect of increasing ruminal butyrate on milk yield and blood constituents in dairy cows fed a grass silage-based diet. J Dairy Sci 1993; 76:1114-24. [PMID: 8486840 DOI: 10.3168/jds.s0022-0302(93)77440-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of increased ruminal supply of butyrate on milk yield, milk composition, and blood metabolites were studied in four lactating cows in a 4 x 4 Latin square design. The basal diet comprised grass silage, hay, and concentrate (34:22:42, DM basis) and was supplemented with isoenergetic VFA infusions (3.58 Mcal/d). A 3:1 molar mixture of acetate and propionate was replaced gradually with butyrate at the rates of 0, 200, 400, or 600 g/d. When the amount of infused butyrate increased, isobutyrate, butyrate, and isovalerate in plasma and acetoacetate and beta-hydroxybutyrate in whole blood increased linearly, but plasma glucose concentration decreased. The latter was associated with a trend toward higher plasma urea concentration, suggesting that more AA were used for gluconeogenesis as the supply of propionate decreased and that of butyrate increased. Milk yield was not changed. The concentrations of milk fat and protein increased, and that of lactose decreased linearly, with the rate of butyrate infusion. Milk fat yield increased, and lactose yield tended to decrease, with increased butyrate infusion. These results indicate that changes in the supply of butyrate do not affect markedly milk yield in cows yielding less than 20 kg/d but cause marked changes in milk composition. The increase in ruminal butyrate supply increased ketogenesis and decreased gluconeogenesis in the liver of lactating dairy cows.
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Affiliation(s)
- P Huhtanen
- Department of Animal Hygiene, College of Veterinary Medicine, Helsinki, Finland
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