Download or read book Effects of Glucose and Acetate Infusion on Milk Protein Yield and Related Gene Expression in Muscle and Mammary Glands of Lactating Dairy Cows written by Boning Li and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study was to explore hypotheses of the mechanism by which NEL stimulates MPY in cows and to determine if glucogenic and lipogenic substrates stimulate MPY by similar mechanisms. Five rumen-fistulated Holstein cows were randomly assigned to a 5 x 5 Latin square design. Treatments were CTL, LoG, HiG, LoA and HiA. Glucose infusion for 5 to 7 d tended to increase milk and protein yields and increased lactose yield. Milk yield, protein yield and lactose yield decreased during acetate infusion. Glucose infusion affected expression of mammary genes related to cell proliferation, differentiation and protein accretion capacity while supplement acetate affected expression of milk protein genes, and those related to protein accretion capacity and cell differentiation.
Download or read book Regulation of Translation by Essential Amino Acids and Glucose in Mammary Glands and Skeletal Muscle of Lactating Dairy Cows written by Kelly Nichols and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Increasing Intravenous Glucose Infusions on Lactation Performance Metabolic Profiles and Metabolic Gene Expression in Dairy Cows written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Knowledge on the precise effects of surplus glucose supply in dairy cows is limited by the lack of information on how intermediary metabolism adapts at different levels of glucose availability. Therefore, a gradual increase of glucose supply via intravenous glucose infusion was used in the present study to test the dose effect of surplus provision of glucose on the metabolic status and milk production of dairy cows. Furthermore, the effects of increasing levels of surplus glucose on mRNA expressions and activities of rate-limiting enzymes involved in hepatic gluconeogenesis were investigated. Based on a previous finding that a positive energy balance may decrease hepatic carnitine palmitoyltransferase (CPT) enzyme activity, it was also of interest whether skeletal muscle CPT activity is downregulated in a similar manner during positive energy balance. Twelve midlactating Holstein-Friesian dairy cows were continuously infused over a 28-d experimental period with either saline (SI group, six cows) or 40% glucose solutions (GI group, six cows). The infusion dose was calculated as a percentage of the daily energy (NEL) requirements by the animal, starting at 0% on d 0 and increasing gradually by 1.25%/d until a maximum dose of 30% was reached by d 24. Dose was then maintained at 30% NEL requirement for 5 d. No infusions were made between d 29-32. Liver and skeletal muscle biopsies were taken on d 0, 8, 16, 24, and 32. Body weight (BW) and back fat thickness (BFT) were recorded on biopsies days. Blood samples were taken every 2 d. In addition, blood samples over 24 h (6-h intervals) were taken the days before each biopsy. Milk and urine samples were taken on biopsies days. BW and BFT increased linearly with increasing glucose dose for GI cows. No differences were observed in the dry matter intake, milk energy output, and energy corrected milk yield between groups. However, milk protein percentage and yield increased linearly in the GI group. Only occasional increases in.
Download or read book Insulin and Trans octadecenoates in Regulation of Milk Fat and Protein Synthesis in Lactating Cows written by Juha Mikko Griinari and published by . This book was released on 1996 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biology of Lactation written by Herbert-H Head and published by Quae. This book was released on 1999-01-01 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: A presentation of the most fundamental features of the biology of the mammary gland, a unique model of an organ capable of an abundant synthesis of proteins: endocrinology of lactation, role of prolactin, genetics and protein synthesis, immunology and the mammary gland, nutrition and dairy products. Readership: students, teachers, researchers, health and agriculture professionals. Lactation Biology was first published in French in 1993. The English version is not merely a translation: it has been updated by the author.
Download or read book EFFECTS OF DIETARY CARBOHYDRATE AND PROTEIN ON MAMMARY NUTRIENT UTILIZATION IN LACTATING DAIRY COWS written by Richelle V. Curtis and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this thesis was to investigate effects of nutritional status, particularly of carbohydrate and protein, on lactational performance, mammary nutrient utilization and gene expression in dairy cows. The first experiment was conducted to characterize mammary transcriptional response to starch level on low- and high-protein diets in eight lactating dairy cows. Cows consuming the high-starch diets had greater milk protein yields (MPY) and greater expression of a translational machinery-related gene, indicating that starch stimulates MPY through increases in translational capacity in mammary secretory cells. The objective of the second experiment was to investigate mammary utilization of blood metabolites, as well as further characterize mammary and muscle gene expression in twelve lactating dairy cows receiving infusions of glucose and two levels of branched-chain amino acids (BCAA) consuming a low-protein diet. Glucose infusions increased milk and MPY, reduced total and BCAA plasma concentrations but did not affect mammary uptakes of amino acids. Provision of BCAA caused reduced MPY, decreased circulating non-branched-chain essential amino acids, as well as mammary uptake, and did not affect plasma urea concentrations. Results indicate that the glucose effect on MPY was not limited by low BCAA concentrations, and that stimulation of non-mammary peripheral tissue use of non-branched-chain essential amino acids by BCAA led to a decrease in MPY. Finally, mammary gene expression was found to be unaffected by infusions or dietary protein and although select expression of genes in the muscle were affected, it was difficult to make any definitive conclusions. The research conducted here in this dissertation has shown that low plasma BCAA are not responsible for the poor stimulation of MPY in response to glucose. Furthermore, it has demonstrated that elevated plasma BCAA concentrations appear to stimulate protein synthesis in non-mammary peripheral tissues rather than in the mammary glands of lactating dairy cows.
Download or read book Relationship Between Mammary Gland Metabolism and Nitrogen Efficiency in the Lactating Dairy Cow written by and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research was to evaluate the responses in mammary metabolism and milk protein yield when the mammary gland is exposed to different nutritional scenarios and to correlate these with efficiency of nitrogen utilization. Two trials were conducted using Latin square designs. The first trial evaluated three dietary CP levels (16.1, 14.6 and 13.2%) with or without abomasal infusion of the predicted limiting essential amino acids (EAA) on 14.6 and 13.2% CP diets. Milk and milk protein yields were not affected by treatment (average 35.4 kg/d and 1.03 kg/d, respectively); efficiency of use of dietary CP and MP increased, and urinary N excretion decreased, as dietary CP decreased. Infusions of EAA increased mammary clearance rate for the non-infused EAA, allowing for the same yield of milk protein despite lower arterial concentrations of these AA in the infused treatments. Overall, efficiency of N utilization did not appear to be affected by changes in mammary metabolism and was probably driven by reduced extra-mammary catabolism as AA supply was reduced. The second trial evaluated post-ruminal infusions of glucose, acetate and casein, alone or in combination. Glucose increased milk protein yield through greater mammary AA clearance rate and reduced AA oxidation within the gland, achieving a 58% efficiency of MP utilization. When glucose was infused with casein, the recovery of infused casein in milk protein was 47%. Acetate had no effect on milk protein yield. Under the condition of this experiment, cell signaling proteins were not affected by treatment and therefore did not help explain the responses to infused nutrients. In conclusion, glucose has a clear stimulating effect on milk protein synthesis and the mammary gland has the ability to increase the supply of nutrients to match its synthetic capacity. Both experiments demonstrated that the NRC (2001) model does not have the ability to predict the responses observed on either low (13.2%) CP diet or with glucose infusion. This indicates that the single nutrient-limiting nature of the NRC (2001) model, which milk and milk protein secretion based only on MP limitation, is insensitive to the interaction of glucose and MP supplies.
Download or read book Abomasal Infusion of Protein and Glucose in Lactating Cows written by Lars Vik-Mo and published by . This book was released on 1973 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Role of Metabolic Signaling in Nutrient Partitioning During Lactation written by Virginia Pszczolkowski and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the hypothesis that metabolic signaling regulates how nutrients are partitioned to support milk synthesis during lactation, with particular emphasis on the dairy cow. First we explored the role of the protein complex mTORC1, a cellular hub of metabolic regulation, in mediating dietary amino acid regulation of murine lactation. Kinase activity of mTORC1 positively regulates cellular anabolic signaling, including protein translation and fat synthesis. Amino acids are both the substrate for protein synthesis-including milk protein-and intracellular signaling molecules that stimulate mTORC1. Feeding lactating animals a protein-restricted diet, therefore, should limit the substrate supply for milk synthesis, as well as reduces anabolic signaling driving that synthesis. Increasing the synthesis of milk components, by definition, means that those components' precursors are simultaneously being partitioned to the synthesizing tissue. We hypothesized that inhibiting mTORC1 activity would reduce lactation performance similarly to restricting protein. We fed lactating mice isoenergetic diets containing adequate protein or restricted protein, and treated half of the adequate protein dams with the mTORC1 inhibitor rapamycin. The dams receiving rapamycin under an adequate protein background and the dams receiving the protein-restricted diet all exhibited reduced pup growth and milk production. In this way, we demonstrated that pharmacologic inhibition of mTORC1 mimics dietary protein restriction in lactating mouse dams, positioning mTORC1 signaling as essential in milk production and successful lactation.Next, we further examined mTORC1 signaling in MAC-T, an immortalized mammary epithelial cell line. Amino acids function to induce mTORC1 localization to the lysosome, where its insulin-activated binding partner Rheb resides. In other models, it has been established that in order for mTORC1 activity to commence following amino acid-driven lysosomal localization, insulin signaling must also be present. We hypothesized that this was also the case in MAC-T. By testing the response in mTORC1 activity to varying concentrations of individual amino acids and insulin, we found that, out of the 10 essential amino acids, only Arg, Ile, Leu, Met, and Thr activate mTORC1 signaling in MAC-T cells, and that this activation requires concurrent stimulation by insulin for greatest response. Following the establishment of which amino acids best interact with insulin to regulate mTORC1 activity in a mammary epithelial cell line, we then sought to test this interaction in lactating cows. We hypothesized that the combination of insulin with Leu and Met-two of the amino acids identified as key in our in vitro study-would result in improved mammary utilization of nutrients for milk synthesis. In this cow study, we raised circulating insulin by means of the hyperinsulinemic-euglycemic clamp, and increased circulating Leu and Met by abomasal infusion. We found that the simplicity suggested by our in vitro experiment belies the complexity of lactation in a cow: there was no interaction between insulin and the amino acids, nor did either treatment independently result in any positive effects on mammary utilization of nutrients or milk production. We did, however, observe responses in plasma concentrations of several nutrients and metabolites, including free fatty acids and amino acids, which were reduced in response to insulin. Insulin is a particularly complex hormone in the context of a lactating dairy cow, because despite the necessity of insulin signaling for cellular metabolic functions like mTORC1 activity in the mammary cells, insulin can also reduce the availability of nutrients for the mammary gland by inducing uptake in non-mammary tissues. Because we did not see evidence that the free fatty acids nor amino acids decreased in circulation were being utilized by the mammary glands for milk synthesis, it is likely that in the context of this experiment, insulin instead stimulated nutrient uptake by other insulin sensitive tissues, partitioning nutrients away from the mammary glands. As insulin partitions nutrients away from the mammary glands, we then sought to investigate the effect of serotonin in nutrient partitioning, a hormone that in lactating cows has been shown to decrease circulating insulin concentration, act as an autocrine-paracrine regulator of mammary and calcium homeostasis in lactation, and perform a variety of other metabolic roles outside of lactation. We raised peripheral serotonin in lactating cows by intravenously infusing them with the serotonin precursor 5-HTP and conducted several experiments in these cows over the course of three weeks to investigate how serotonin may participate in nutrient partitioning to the mammary glands. In performing an intravenous glucose tolerance test on the cows, we determined that elevated serotonin both reduced the insulin response and blunted the decrease in free fatty acids following the glucose challenge, without altering the glucose dynamics themselves. The maintenance of normoglycemia under lower insulin conditions, coupled with elevated free fatty acids, suggests that serotonin stimulates insulin-independent glucose disposal, and increases free fatty acid availability for mammary gland usage. When we then assessed serotonin's broader effects on metabolic function, mammary extraction of nutrients, and subsequent milk production, we found transiently decreased circulating insulin, increased circulating free fatty acids, and increased mammary free fatty acid extraction, all of which indicate increased free fatty acid partitioning to the mammary glands. This partitioning was not, however, borne out in improved milk production, which was instead decreased in concert with infusion of 5-HTP. Elevated serotonin also increased the incidence and frequency of loose manure during and shortly after infusion, in line with its known effects on gut motility, and reduced feed intake in a manner antithetical to the support of lactation. This work in serotonin may have been limited by the experimental approach used, with 5-HTP rather than serotonin itself administered in a bolus fashion, potentially driving strongly transient effects in both the periphery and central nervous system. This could effect serotonergic responses that are disparate from what is possible with endogenous mammary serotonin production alone. Overall, through the work of this dissertation, we have identified the importance of insulin in cellular signaling within the mammary epithelial cells to drive milk synthesis, but also that, within the physiologic context of a lactating animal, insulin has non-mammary functions that may contradict its signaling role in mammary cells, reducing substrate availability for milk synthesis. As with insulin, peripheral serotonin is part of a complex system that can yield equally complex outcomes. While serotonin can improve milk substrate availability in the circulation and improve the mammary extraction of some of those substrates, it can simultaneously reduce the availability of other substrates by limiting their availability and absorption from the diet. Broadly, understanding how amino acids, insulin, and serotonin interact to regulate metabolism function during lactation will better position lactation physiologists and nutritionists to understand and manipulate metabolism during lactation. In this way, this work advances the pursuit of improved productive efficiency and treatment and prevention of metabolic disorders in dairy cows.
Download or read book Studies on the Regulation of Milk Protein Concentration and Yield in Dairy Cows written by Timothy Ronald Mackle and published by . This book was released on 1999 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MAMMARY MTOR ACTIVITY DURING INTRAVENOUS GLUCOSE INFUSIONS INTO LACTATING DAIRY COWS written by Richelle Curtis and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of glucose on milk protein yield and mammary mTOR activity were studied in eight multiparous early lactation Holstein cows fed a TMR with 40% NDF content. Treatments were jugular infusions of either physiological saline (SAL) or approximately 900 g/d glucose (GLC) in a cross over design for two 6 d periods during which blood, milk and mammary tissue were sampled. GLC infusion increased plasma insulin but did not significantly increase plasma glucose and only tended to increase milk protein yields. NEAA and BCAA plasma concentrations significantly increased and decreased, respectively, with GLC treatments. Furthermore, reduction of the phosphorylation state of mTOR signalling protein 4EBP1, as well as reduction of total and phosphorylated S6K1 abundances resulted from the infusion of GLC. The expected increase in milk protein synthesis due to glucose infusion was not observed, presumably because protein synthesis was stimulated in muscle tissue rather than the mammary glands.
Download or read book Characterization of insulin sensitivity and inflammation related factors in dairy cows receiving conjugated linoleic acids CLA or a control fat supplement during lactation written by Behnam Saremi and published by Cuvillier Verlag. This book was released on 2013-06-03 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the onset of lactation, dairy cows have to mobilize body reserves, mainly body fat, to cover the output of energy via milk. The homeorhetic metabolic adaptation to the needs of milk production is accomplished through the orchestrated action of hormones. In contrast to the “classical hormones” that knowingly control parturition, lactation and metabolism, the role and importance of messenger molecules originating from body fat (adipokines), of their receptors and also of nuclear receptors as key regulators of gene expression was only scarcely investigated in dairy cows. In particular, data on body fat were largely limited to subcutaneous (s.c.) fat from one location easily accessible via biopsy, whereas potentially heterogeneous reactions between different s.c. depots and also in different visceral (v.c.) fat were not yet comprehensively addressed. The aim of this dissertation was to characterize the mRNA expression of several adipokines and related factors that are involved in insulin sensitivity (IS) and in inflammation during the transition from pregnancy to lactation and during the subsequent lactation. In addition, dietary supplementation with either CLA vs. a control fat (supplementation period day 1 to day 105 or 182 of lactation) was tested for potential effects on the target mRNAs. The tissue in focus was adipose tissue (AT) with its different locations. Initially, suitable reference genes were identified as a methodological prerequisite for the studies. Using tissue samples obtained from both primiparous and pluriparous cows from animal experiments within a project cooperation, the time course of the mRNA abundance of 12 different target genes and 7 reference genes was characterized in s.c. fat and in liver from pluriparous cows and in three different s.c. and in three v.c. fat depots, in liver, skeletal muscle, and in mammary gland from primiparous cows. Two acute phase proteins, i.e. haptoglobin (Hp) and serum amyloid A3 (SAA3), were newly established as adipokines in cattle; both mRNAs yielded similar time course patterns with a peripartal peak. Treatment with CLA was mostly not affecting Hp and SAA3 mRNA expression; the decrease observed for Hp and SAA3 mRNA in 2 out of 6 fat depots tested indicates local anti-inflammatory effects of CLA. No CLA effect was observed for the Hp serum concentrations and for hepatic Hp mRNA. Indeed, we confirmed liver as the main site of Hp production. For the prioritization of nutrient uptake towards the mammary gland, IS in other peripheral organs is knowingly reduced. The mRNA expression of the target genes related with IS, i.e. adiponectin (ADIPOQ), leptin (LEP), their receptors (LEPR, LEPRB, ADIPOR1, ADIPOR2), of two nuclear receptor isoforms (PPARγ, PPARγ2) and of two pro-inflammatory cytokines (TNF-α, IL-6) in s.c.AT and in liver from pluriparous cows was mostly decreased from day 21 prepartum to day 21 postpartum in s.c.AT except TNF-α; in liver increases were observed for LEPRB and ADIPOR2, and decreasing abundance for all other hepatic target mRNAs except TNF-α and ADIPOR1 which remained constant in this time. In later lactation, prepartum values were reached again and were largely maintained until wk 36. The groups treated with CLA or control fat differed detachedly in mRNA abundance of PPARγ, LEPRB and TNF-α in liver and of PPARγ2 in s.c.AT; cows of the CLA group had also higher insulin concentrations and reduced systemic IS persisting after the end of CLA supplementation. In primiparous cows, changes with the duration of lactation were observed for most of the target mRNAs (except LEP) but not in all tissues investigated; time course and direction of change were partly divergent between the different tissues. CLA treatment for 105 days decreased the mRNA abundance of ADIPOQ, ADIPOR2, PPARγ2 and TNF-α in v.c.AT and in the mammary gland. The results of these studies provide a longitudinal characterization of the expression of genes that are particularly related to AT as a heterogeneous functional regulator in lactating dairy cows. The known effect of CLA inhibiting milk fat synthesis might at least be partly explained by the down-regulation of PPARγ2 in the mammary gland observed herein. The importance of the CLA induced effects on IS for animal health can presently not be finally assessed due to lack of validated reference values for IS in high yielding dairy cows.
Download or read book The Role of Metabolic Signaling in Nutrient Partitioning During Lactation written by Virginia Loretta Pszczolkowski and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines the hypothesis that metabolic signaling regulates how nutrients are partitioned to support milk synthesis during lactation, with particular emphasis on the dairy cow. First we explored the role of the protein complex mTORC1, a cellular hub of metabolic regulation, in mediating dietary amino acid regulation of murine lactation. Kinase activity of mTORC1 positively regulates cellular anabolic signaling, including protein translation and fat synthesis. Amino acids are both the substrate for protein synthesis-including milk protein-and intracellular signaling molecules that stimulate mTORC1. Feeding lactating animals a protein-restricted diet, therefore, should limit the substrate supply for milk synthesis, as well as reduces anabolic signaling driving that synthesis. Increasing the synthesis of milk components, by definition, means that those components' precursors are simultaneously being partitioned to the synthesizing tissue. We hypothesized that inhibiting mTORC1 activity would reduce lactation performance similarly to restricting protein. We fed lactating mice isoenergetic diets containing adequate protein or restricted protein, and treated half of the adequate protein dams with the mTORC1 inhibitor rapamycin. The dams receiving rapamycin under an adequate protein background and the dams receiving the protein-restricted diet all exhibited reduced pup growth and milk production. In this way, we demonstrated that pharmacologic inhibition of mTORC1 mimics dietary protein restriction in lactating mouse dams, positioning mTORC1 signaling as essential in milk production and successful lactation.Next, we further examined mTORC1 signaling in MAC-T, an immortalized mammary epithelial cell line. Amino acids function to induce mTORC1 localization to the lysosome, where its insulin-activated binding partner Rheb resides. In other models, it has been established that in order for mTORC1 activity to commence following amino acid-driven lysosomal localization, insulin signaling must also be present. We hypothesized that this was also the case in MAC-T. By testing the response in mTORC1 activity to varying concentrations of individual amino acids and insulin, we found that, out of the 10 essential amino acids, only Arg, Ile, Leu, Met, and Thr activate mTORC1 signaling in MAC-T cells, and that this activation requires concurrent stimulation by insulin for greatest response. Following the establishment of which amino acids best interact with insulin to regulate mTORC1 activity in a mammary epithelial cell line, we then sought to test this interaction in lactating cows. We hypothesized that the combination of insulin with Leu and Met-two of the amino acids identified as key in our in vitro study-would result in improved mammary utilization of nutrients for milk synthesis. In this cow study, we raised circulating insulin by means of the hyperinsulinemic-euglycemic clamp, and increased circulating Leu and Met by abomasal infusion. We found that the simplicity suggested by our in vitro experiment belies the complexity of lactation in a cow: there was no interaction between insulin and the amino acids, nor did either treatment independently result in any positive effects on mammary utilization of nutrients or milk production. We did, however, observe responses in plasma concentrations of several nutrients and metabolites, including free fatty acids and amino acids, which were reduced in response to insulin. Insulin is a particularly complex hormone in the context of a lactating dairy cow, because despite the necessity of insulin signaling for cellular metabolic functions like mTORC1 activity in the mammary cells, insulin can also reduce the availability of nutrients for the mammary gland by inducing uptake in non-mammary tissues. Because we did not see evidence that the free fatty acids nor amino acids decreased in circulation were being utilized by the mammary glands for milk synthesis, it is likely that in the context of this experiment, insulin instead stimulated nutrient uptake by other insulin sensitive tissues, partitioning nutrients away from the mammary glands. As insulin partitions nutrients away from the mammary glands, we then sought to investigate the effect of serotonin in nutrient partitioning, a hormone that in lactating cows has been shown to decrease circulating insulin concentration, act as an autocrine-paracrine regulator of mammary and calcium homeostasis in lactation, and perform a variety of other metabolic roles outside of lactation. We raised peripheral serotonin in lactating cows by intravenously infusing them with the serotonin precursor 5-HTP and conducted several experiments in these cows over the course of three weeks to investigate how serotonin may participate in nutrient partitioning to the mammary glands. In performing an intravenous glucose tolerance test on the cows, we determined that elevated serotonin both reduced the insulin response and blunted the decrease in free fatty acids following the glucose challenge, without altering the glucose dynamics themselves. The maintenance of normoglycemia under lower insulin conditions, coupled with elevated free fatty acids, suggests that serotonin stimulates insulin-independent glucose disposal, and increases free fatty acid availability for mammary gland usage. When we then assessed serotonin's broader effects on metabolic function, mammary extraction of nutrients, and subsequent milk production, we found transiently decreased circulating insulin, increased circulating free fatty acids, and increased mammary free fatty acid extraction, all of which indicate increased free fatty acid partitioning to the mammary glands. This partitioning was not, however, borne out in improved milk production, which was instead decreased in concert with infusion of 5-HTP. Elevated serotonin also increased the incidence and frequency of loose manure during and shortly after infusion, in line with its known effects on gut motility, and reduced feed intake in a manner antithetical to the support of lactation. This work in serotonin may have been limited by the experimental approach used, with 5-HTP rather than serotonin itself administered in a bolus fashion, potentially driving strongly transient effects in both the periphery and central nervous system. This could effect serotonergic responses that are disparate from what is possible with endogenous mammary serotonin production alone. Overall, through the work of this dissertation, we have identified the importance of insulin in cellular signaling within the mammary epithelial cells to drive milk synthesis, but also that, within the physiologic context of a lactating animal, insulin has non-mammary functions that may contradict its signaling role in mammary cells, reducing substrate availability for milk synthesis. As with insulin, peripheral serotonin is part of a complex system that can yield equally complex outcomes. While serotonin can improve milk substrate availability in the circulation and improve the mammary extraction of some of those substrates, it can simultaneously reduce the availability of other substrates by limiting their availability and absorption from the diet. Broadly, understanding how amino acids, insulin, and serotonin interact to regulate metabolism function during lactation will better position lactation physiologists and nutritionists to understand and manipulate metabolism during lactation. In this way, this work advances the pursuit of improved productive efficiency and treatment and prevention of metabolic disorders in dairy cows.
Download or read book The gestating and lactating sow written by Chantal Farmer and published by BRILL. This book was released on 2023-09-04 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last book on the lactating sow was published over 15 years ago. This new book brings us up to date in current knowledge on the gestating and lactating sow. It covers new and important topics such as conditioning of gilts for optimal reproductive performance, feeding high fibre diets to gestating sows and providing various fat sources in gestation and lactation. It also describes the several key success factors to group-housing systems in gestation, which is a must due to the current move towards group-housing. The new concept of transition feeding for sows is discussed, as well as the factors involved in mammary development of gilts and sows, both of which are instrumental for maximum colostrum and/or milk yields. The impact of the human-animal interactions on sow welfare and performance is discussed with focus on new handling practices that could be developed to overbalance the negative interactions inherent to pig management systems. Updates on must-have topics, such as amino acid and energy requirements of sows, colostrum and milk yield and composition, and sow health are also provided. The subjects covered in this book will assist animal scientists, nutritionists, veterinarians and swine producers in learning the most recent information on relevant and current topics affecting sow production, and in knowing which areas are in need of further research efforts.
Download or read book The Effects of Two Forms of Slow release Insulin on Lactating Dairy Cow Metabolism and Milk Component Production written by Laurie Ann Winkelman and published by . This book was released on 2011 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Milk protein is the most valuable milk component for which dairy producers receive payment. Despite its high value, altering milk protein composition and production in dairy cows by diet has been challenging, particularly as compared to altering milk fat. Improving the efficiency of conversion of dietary nitrogen into productive nitrogen (as milk protein) has both financial and environmental benefits to the dairy industry. Dietary strategies to improve milk protein yield have focused on amino acid requirements, metabolizable protein, and the interaction between dietary energy and protein. However, dietary interventions have had only moderate success in improving milk protein production in well-fed dairy cows. Use of long-term hyperinsulinemic-euglycemic clamps in lactating cows has suggested that milk protein synthesis in dairy cows is not maximized under normal management conditions, as significant improvements in milk protein have been observed in this experimental context. The goal of the present research was to expand on these observations by administering slow-release insulins, from human medicine, to lactating dairy cows. The hypothesis was that administration of slow-release insulins, without provision of supplemental glucose, would increase milk protein production and alter mammary metabolism in lactating dairy cows. In experiment one, two forms of slow-release insulin were tested in a dose response study. Both Humulin-N (H) and insulin glargine (L) exerted insulin-like effects in lactating dairy cows, evidenced by linear decreases of plasma glucose with increasing dose of slow-release insulin. In experiment two, H and L were given twice daily for 10 days to evaluate their effects on milk component production. Milk fat and protein content were both increased by treatment with H and L, suggesting that these forms of slow-release insulin alter metabolism and milk component synthesis. In experiment three, L was used in a mammary metabolism study to examine its effects on mammary uptake and utilization of substrates for protein synthesis. Reduced uptake of both essential and nonessential amino acids was observed during treatment with L, while milk protein yield remained the same for the control and treatment periods. This suggests that L alters metabolism and increases amino acid efficiency of use within the cow.
Download or read book Metabolic Modifiers written by National Research Council and published by National Academies. This book was released on 1994-02-01 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, animal scientists have learned that administering recombinantly derived somatotropin (growth hormone) to cows improves milk production and that giving beta-adrenergic agonists to meat animals improves productivity and leanness. In order for these metabolic modifiers to yield benefits, however, sound management of the animals' nutrition is necessary. This volume reports on how these substances work in the animals' metabolism, what effects they might have on nutrient requirements of domestic livestock, and what information should be developed further by investigators. The book explores the current understanding of the biology, structure, mechanisms of action, and treatment effects of somatotropin, beta-adrenergic agonists, and anabolic steroids. A companion volume to the Nutrient Requirements of Domestic Animals series, this authoritative volume will be required reading for animal scientists, researchers, veterinarians, livestock farmers, and faculty and students in university animal veterinary science programs.
Download or read book The Effect of Abomasal Infusion of Histidine and Proline on Milk Composition and Mammary Amino Acid Utilization in High Producing Lactating Dairy Cows written by Megan Wiles Hofherr and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The high cost of feed and increasing necessity to reduce nitrogen (N) waste in dairy production systems has driven research in the area of improving milk protein synthesis and overall efficiency of N utilization in lactating dairy cows. One strategy that has been investigated is reducing the total crude protein (CP) level of the diet while supplementing the ration with limiting amino acids (AA) for milk production. However, currently there is not enough information on the effects of increasing absorptive supply of certain individual AA on productive performance and mammary metabolism in high producing lactating dairy cows. Specifically, histidine (His) has been shown to be a limiting amino acid in grass fed lactating dairy cows and to alter fat secretion under certain conditions. In one published study in which the nonessential AA proline (Pro) was infused into the duodenum of two cows, a significant increase in milk protein output and a reduction in arginine (Arg) uptake by the mammary gland were observed. The objective of this study was to determine the effect of abomasal infusion of His and Pro, separately and in combination, on productive performance and mammary amino acid utilization in high producing lactating dairy cows. Four rumen-fistulated Holstein cows (52 [PLUS OR MINUS]16 DIM) with indwelling intercostal arterial catheters were used in a 4 x 4 Latin square experiment. Experimental treatments were continuous abomasal infusion of water (Control), His (H, 10g/d), Pro (P, 20 g/d), and His (10 g/d) + Pro (20 g/d)(H+P), with 7-d treatment periods. Cows were fed a TMR (15.6 % CP, 2.7 Mcals/kg ME) once per day for ad libitum intake, and refusals were measured and analyzed. The CNCPS v6.1 was used to formulate a diet to exceed the metabolizable energy requirement, provide 95% of the predicted metabolizable protein requirement, and supply adequate amounts of all essential amino acids, except Arg. Compared to the Control treatment, abomasal infusion of Pro decreased dry matter intake (DMI) by 1.8 kg/d and improved feed efficiency (P [LESS-THAN OR EQUAL TO] 0.05) by 0.16 kg 3.5% FCM per kg dry matter. Fat corrected milk (FCM) yields were not affected by treatment (51.8 kg/d, TRT C; 50.6 kg/d, TRT H; 49.0 kg/d TRT H+P; 52.4 kg/d TRT P). Abomasal infusion of His resulted in no difference in milk yield or composition, and there was no effect of Pro infusion on protein and fat contents and yields. Pro infusion increased lactose percentage (P [LESS-THAN OR EQUAL TO] 0.05) but not yield. The lactose response suggests that longer infusions might have resulted in increased milk yield. Mammary blood flow, expressed as L plasma/L milk, was not significantly different among treatments; though, Pro infusion increased blood flow by 14% relative to the control treatment (694.8 vs. 606.8 L plasma/L milk for P and C, respectively). Arterial concentration of His tended to be higher for His infusion than for both water and Pro infusions. The AV differences for all EAA were not affected by AA infusion; however, AV differences for Asp, Cys, Glu, and Cit were numerically lowest for Pro infusion, with no changes for other NEAA. Compared to the Control infusion, His infusion decreased extraction efficiency of His by the mammary gland. Although the P treatment did not significantly affect arterial concentration, AV difference, or extraction rate of Pro or Arg when compared to values for the control, it appears that Pro infusion tended to alter extraction efficiency and mammary uptake of Cit and Val. Results of this experiment suggest that His does not limit milk production or milk protein synthesis in high producing lactating dairy cows fed corn silage based rations. Lactation performance and feed efficiency were not improved by abomasal infusion of His and Pro, simultaneously. Unlike results of other studies, increased absorptive supply of both His and Pro did not increase milk protein synthesis in this experiment. Further, abomasal infusion of Pro did not reduce Arg uptake by the mammary gland, which is not consistent with other experiments in which Pro was infused postruminally in lactating cows and goats. However, this work does suggest that postruminal supplementation of Pro might improve feed efficiency and alter milk fat secretion in high producing dairy cows in early lactation.
