Slow digestion-oriented dietary strategy to sustain the secretion of GLP-1 for improved glucose homeostasis

Dysregulated glucose metabolism is associated with many chronic diseases such as obesity and type 2 diabetes mellitus (T2DM), and strategies to restore and maintain glucose homeostasis are essential to health. The incretin hormone of glucagon-like peptide-1 (GLP-1) is known to play a critical role in regulating glucose homeostasis and dietary nutrients are the primary stimuli to the release of intestinal GLP-1. However, the GLP-1 producing enteroendocrine L-cells are mainly distributed in the distal region of the gastrointestinal tract where there are almost no nutrients to stimulate the secretion of GLP-1 under normal situations. Thus, a dietary strategy to sustain the release of GLP-1 was proposed, and the slow digestion property and dipeptidyl peptidase IV (DPP-IV) inhibitory activity of food components, approaches to reduce the rate of food digestion, and mechanisms to sustain the release of GLP-1 were reviewed. A slow digestion-oriented dietary approach through encapsulation of nutrients, incorporation of viscous dietary fibers, and enzyme inhibitors of phytochemicals in a designed whole food matrix will be implemented to efficiently reduce the digestion rate of food nutrients, potentiate their distal deposition and a sustained secretion of GLP-1, which will be beneficial to improved glucose homeostasis and health.     

Plasma concentrations of gut peptides in dairy cattle increase after calving

Effects of transition from late gestation to early lactation on plasma concentrations of glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1-(7-36) amide (GLP-1), and cholecystokinin (CCK) have not been reported in cattle. The objective of the present study was to measure plasma concentrations of GLP-1, GIP, CCK, insulin, glucose, and nonesterified fatty acids in blood plasma obtained from the coccygeal vein of 32 Holstein cows at an average of 11 d before, and 5, 12, and 19 d after calving. Feed dry matter intake (DMI) averaged 14.4, 17.7, and 19.9 kg/d on d 5, 12, and 19 of lactation, respectively, as milk yield increased (30.6, 36.6, and 39.7 kg/d, respectively). Plasma concentrations of insulin and glucose were lower postpartum than prepartum, but did not differ among samples collected after calving. In contrast, plasma concentration of gut peptides increased linearly after calving, perhaps as a consequence of increased feed intake and nutrient absorption; however, the increases in plasma concentrations of GIP and GLP-1 as lactation progressed were not associated with increased DMI per se, and likely reflect the endocrine and metabolic adaptations of lacto-genesis. In contrast, increased concentration of CCK was related both to increasing days in milk and DMI. By 19 d postpartum, concentrations of GLP-1, GIP, and CCK increased by 2.3-, 1.8-, and 2.8-fold, respectively, compared with values at 11 d before calving. Although these peptides have direct and indirect effects that reduce appetite and DMI in other species (including increased insulin secretion), these may be glucose- or insulin-dependent functions, and insulin and glucose concentrations were reduced in early lactation.     

Gut: A key player in the pathogenesis of type 2 diabetes?

The gut regulates glucose and energy homeostasis; thus, the presence of ingested nutrients into the gut activates sensing mechanisms that affect both glucose homeostasis and regulate food intake. Increasing evidence suggest that gut may also play a key role in the pathogenesis of type 2 diabetes which may be related to both the intestinal microbiological profile and patterns of gut hormones secretion. Intestinal microbiota includes trillions of microorganisms but its composition and function may be adversely affected in type 2 diabetes. The intestinal microbiota may be responsible of the secretion of molecules that may impair insulin secretion/action. At the same time, intestinal milieu regulates the secretion of hormones such as GLP-1, GIP, ghrelin, gastrin, somatostatin, CCK, serotonin, peptide YY, GLP-2, all of which importantly influence metabolism in general and in particular glucose metabolism. Thus, the aim of this paper is to review the current evidence on the role of the gut in the pathogenesis of type 2 diabetes, taking into account both hormonal and microbiological aspects.     

Effects of pulse-dose ruminal infusion of butyrate on plasma glucagon-like peptide 1 and 2 concentrations in dairy calves

Feeding of butyrate was found to have a positive effects in enhancing gut development and improving growth performance of calves. Equally, glucagon-like peptide 1 and 2 (GLP-1 and GLP-2), secreted from gastrointestinal L-cells in response to nutrient intake, were found to play a significant role in regulating blood glucose homeostasis and improving gut health. However, limited information is available about the relationship between butyrate and release of GLP-1 and GLP-2 in dairy calves. The objective of this study was to evaluate the effects of a pulse-dose ruminal infusion of butyrate on plasma GLP-1 and GLP-2 concentrations in dairy calves. Five ruminally cannulated mature Holstein bull calves (7.2 ± 0.10 mo, and 330 ± 16.0 kg of body weight; mean ± standard deviation) were used in a 5 × 5 Latin square with 4-d periods. On d 1 of each period at 0800 h, calves were ruminally infused with 1 of 5 treatments: 0 (saline), 0.3, 0.6, 0.9, and 1.2 g of butyrate per kg of body weight. Before butyrate infusion, calves were not offered feed overnight, and sequential blood and rumen fluid samples were taken before and after infusion on d 1 of each period. Ruminal butyrate and total volatile fatty acid concentrations increased linearly (2.65, 12.19, 20.99, 30.19, and 36.30; 23.68, 33.07, 40.94, 51.13, and 56.31 µmol/mL, for butyrate and total volatile fatty acids, respectively) in a dose-dependent manner, whereas propionate and isobutyrate increased quadratically. Ruminal and plasma butyrate, β-hydroxybutyrate, GLP-1, GLP-2, insulin, and glucose concentrations were all affected by treatment, time (except GLP-2), and interaction of treatment with time (except GLP-1). The area under the curve (AUC) summarized at different time points relative to the baseline (AUC30, AUC60, AUC120, and AUC240) for ruminal and plasma butyrate, and BHB, increased linearly with the dose of butyrate infused. However, AUC30, AUC60, AUC120, and AUC240 for plasma GLP-2 concentration were affected in a cubic manner unlike the linear effect on AUC30 and AUC60 for GLP-1. Plasma GLP-2 was not correlated with plasma butyrate (r = 0.16), GLP-1 (r = 0.03), or BHB (r = ?0.05). This findings suggest that pulse-dosing of butyrate slightly increased both GLP-1 and GLP-2 concentrations at specific time points and this might be promoted by direct or indirect effect of butyrate on the intestinal L-cells.     

Peptide-YY Is Released by the Intestinal Cell Line STC-1

ABSTRACT:  Dietary modulation of the response of gut satiety hormones, which partly regulate food intake, provides a promising treatment for overweight and obesity. Gut-derived cell lines such as STC-1 are widely used to investigate these hormonal responses to nutrients. To date, no peptide-YY (PYY) secreting cell line has been identified. The aim of this study was to investigate whether STC-1 cells are able to secrete PYY and if so, whether dietary compounds can modulate PYY secretion. The effects of fatty acid types C4:0, C12:0, C14:0, C16:0, and C18:0 on PYY release were investigated by measuring PYY in the supernatant after 30, 60, 90, and 120 min of incubation, respectively, using RIA assays. The STC-1 cells were able to secrete PYY in a time-dependent manner. It was shown that after 30 min, C4:0, C12:0, C16:0, and C18:0 caused increased PYY levels compared to the control. At time points 60 and 90 min, C4:0 and C18:0 induced elevated PYY levels compared to the control. After 120 min, C4:0, C14:0, and C18:0 caused elevated levels compared to the control. We are the first to show that the STC-1 cells are also able to secrete PYY next to cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1). Addition of fatty acids resulted in increased levels of PYY, which is consistent with the literature describing human studies. We conclude that the STC-1 cell line provides an appropriate cell line for screening the effects of ingredients on the release of the satiety-related gut hormones CCK, GLP-1, and PYY.     

In vitro evidence for gut hormone stimulation release and dipeptidyl-peptidase IV inhibitory activity of protein hydrolysate obtained from cuttlefish (Sepia officinalis) viscera

Two cuttlefish (Sepia officinalis) viscera protein hydrolysates were obtained with different enzymes extracted from cuttlefish and smooth hound (Mustellus mustellus). Their ability to stimulate the secretion of cholecystokinin (CCK) and glucagon-like peptide 1 (GLP-1), using the enteroendocrine STC-1 cell line, and to inhibit the DPP-IV activity during a simulated gastrointestinal digestion was assayed. The physico-chemical parameters of hydrolysates and their effects on intestinal cell viability were also determined. The hydrolysate obtained with cuttlefish enzymes (CVPH1) appeared to be the most promising for all assessed bioactivities. Thus CVPH1 was able to stimulate CCK and active GLP-1 releasing activities of enteroendocrine cells without any cytotoxicity and to inhibit DPP-IV activity. Moreover, these actions were enhanced after gastrointestinal digestion and CVPH1 was also able to inhibit the intestinal DPP-IV activity of Caco-2 cells. These very promising findings highlight, via two different mechanisms, the positive effect of CVPH1 on GLP-1 actions.     

Sustained glucagon-like peptide 1 expression from encapsulated transduced cells to treat obese diabetic rats

Obesity and type 2 diabetes (T2D) are two prevalent chronic diseases that have become a major public health concern in industrialized countries. T2D is characterized by hyperglycemia and islet beta cell dysfunction. Glucagon-like peptide 1 (GLP-1) promotes β cell proliferation and neogenesis and has a potent insulinotropic effect. Leptin receptor deficient male rats are obese and diabetic and provide a model of T2D. We hypothesized that their treatment by sustained expression of GLP-1 using encapsulated cells may prevent or delay diabetes onset. Vascular smooth muscle cells (VSMC) retrovirally transduced to secrete GLP-1 were seeded into TheraCyte(TM) encapsulation devices, implanted subcutaneously and rats were monitored for diabetes. Rats that received cell implants showed mean plasma GLP-1 level of 119.3 ± 10.2pM that was significantly elevated over control values of 32.4 ± 2.9pM (P<0.001). GLP-1 treated rats had mean insulin levels of 45.9 ± 2.3ng/ml that were significantly increased over control levels of 7.3±1.5ng/ml (P<0.001). In rats treated before diabetes onset elevations in blood glucose were delayed and rats treated after onset became normoglycemic and showed improved glucose tolerance tests. Untreated diabetic rats possess abnormal islet structures characterized by enlarged islets with α-cell infiltration and multifocal vacuolization. GLP-1 treatment induced normalization of islet structures including a mantle of α-cells and increased islet mass. These data suggest that encapsulated transduced cells may offer a potential long term treatment of patients.     

GATA-like protein-1 (GLP-1) is required for normal germ cell development during embryonic oogenesis

Oogenesis and primordial follicle formation are tightly linked processes, requiring organized and precisely timed communication between somatic and germ cells. Deviations in ovarian cell cross talk, or aberrant gene expression within one of the cell populations, can lead to follicle loss or dysfunction, resulting in infertility. Expression of GATA-like protein-1 (GLP-1) in ovarian somatic cells is required for normal fertility in female mice, as GLP-1 deficiency leads to the absence of oocytes at birth. However, the timing and nature of this germ cell loss is not well understood. In this study, we characterize the embryonic germ cell loss in GLP-1 null mice. Quantitative PCR demonstrates that ovarian Glp-1 mRNA is expressed in a bimodal pattern during embryogenesis, peaking at E13.5-14.5 and again at birth. In contrast, adult ovaries express low but detectable levels of Glp-1 mRNA. Analysis of developing GLP-1 null mouse ovaries shows that germ cells are appropriately specified and migrate normally to nascent gonads. Upon arrival at the gonad, precocious loss of germ cells begins at around E13.5. This loss is completed by birth and is accompanied by defects in the expression of genes associated with meiotic entry. Interestingly, somatic pregranulosa cells still form basement membranes surrounding germ line cysts and express mRNA encoding paracrine signaling molecules that communicate with oocytes, albeit at lower levels than normal. Together, these data imply that the somatic cell protein GLP-1 is not necessary for many pregranulosa cell functions but is required for germ cell survival.     

Feeding rumen-inert fats differing in their degree of saturation decreases intake and increases plasma concentrations of gut peptides in lactating dairy cows

Our objective was to determine the effect of feeding rumen-inert fats differing in their degree of saturation on dry matter intake (DMI), milk production, and plasma concentrations of insulin, glucagon-like peptide 1 (7-36) amide (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and cholecystokinin (CCK) in lactating dairy cows. Four midlactation, primiparous Holstein cows were used in a 4 × 4 Latin square experiment with 2-wk periods. Cows were fed a control mixed ration ad libitum, and treatments were the dietary addition (3.5% of ration dry matter) of 3 rumen-inert fats as sources of mostly saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), or polyunsaturated fatty acids (PUFA). Daily DMI, milk yield, and composition were measured on the last 4 d of each period. Jugular vein blood was collected every 30 min over a 7-h period on d 12 and 14 of each period for analysis of plasma concentrations of hormones, glucose, and nonesterified fatty acids. Feeding fat decreased DMI, and the decrease tended to be greater for MUFA and PUFA compared with SFA. Plasma concentration of GLP-1 increased when fat was fed and was greater for MUFA and PUFA. Feeding fat increased plasma glucose-dependent insulinotropic polypeptide and CCK concentrations and decreased plasma insulin concentration. Plasma CCK concentration was greater for MUFA and PUFA than for SFA and was greater for MUFA than PUFA. Decreases in DMI in cows fed fat were associated with increased plasma concentrations of GLP-1 and CCK and a decreased insulin concentration. The role of these peptides in regulating DMI in cattle fed fat requires further investigation.     

Effect of cellular inositol content on ethanol tolerance of Saccharomyces cerevisiae in sake brewing

The effect of cellular inositol content on the ethanol tolerance of sake yeast was investigated. In a static culture of strain K901 in a synthetic medium, when cells were grown in the presence of inositol in limited amount (L-cells), the inositol content of cells decreased by one-third that of cells grown in the presence of inositol in sufficient amount (H-cells). L-cells exhibited a higher death rate constant than H-cells in the presence of 12-20% ethanol, while no difference in specific ethanol production rate in the presence of 0-18% ethanol between the two cell types was observed. L-cells leaked more intracellular components, such as nucleotides, phosphate and potassium, in the presence of ethanol than H-cells. L-cells exhibited a lower intracellular pH value than H-cells, which represented the lowering of cell vitality by the decrease in H(+) extrusion activity. Furthermore, the plasma membrane H(+)-ATPase activity of L-cells was approximately one-half of that of H-cells. Therefore, it was considered that the decrease in viability in the presence of ethanol due to inositol limitation results from the lowering of H(+)-ATPase activity, which maintains the permeability barrier of the yeast membrane, ensuring the homeostasis of ions in the cytoplasm of yeast cells. It is assumed that the lowering of H(+)-ATPase activity due to inositol limitation is caused by the change in lipid environment of the enzyme, which is affected by inositol-containing glycerophospholipids such as phosphatidylinositol (PI), because in the PI-saturated mixed micellar assay system, the difference in H(+)-ATPase activity between L- and H-cells disappeared. In the early stage of sake mash, inositol limitation lowers the ethanol tolerance due to the decrease in H(+)-ATPase activity as in static culture. In the final stage of sake mash, the disruption of the ino1 gene responsible for inositol synthesis, resulted in a decrease in cell density. Furthermore, the ino1 disruptant, which was not capable of increasing the cellular inositol level in the final stage, exhibited a significantly higher methylene blue-staining ratio than the parental strain. It was suggested that the yeast cellular inositol level is one of the important factors which contribute to the high ethanol tolerance implied by the increased cell viability in the presence of ethanol.     

Could hop-derived bitter compounds improve glucose homeostasis by stimulating the secretion of GLP-1?

Hops (Humulus lupulus L.) is by far the greatest contributors to the bitter property of beer. Over the past years, a large body of evidence demonstrated the presence of taste receptors in different locations of the oral cavity. In addition to the taste buds of the tongue, cells expressing these receptors have been identified in olfactory bulbs, respiratory and gastrointestinal tract. In the gut, the attention was mainly directed to sweet Taste Receptor (T1R) and bitter Taste Receptor (T2R) receptors. In particular, T2R has shown to modulate secretion of different gut hormones, mainly Glucagon-like Peptide 1 (GLP-1), which are involved in the regulation of glucose homeostasis and the control of gut motility, thereby increasing the sense of satiety. Scientific interest in the activity of bitter taste receptors emerges because of their wide distribution in the human species and the large range of natural substances that interact with them. Beer, whose alcohol content is lower than in other common alcoholic beverages, contains a considerable amount of bitter compounds and current scientific evidence shows a direct effect of beer compounds on glucose homeostasis. The purpose of this paper is to review the available literature data in order to substantiate the novel hypothesis of a possible direct effect of hop-derived bitter compounds on secretion of GLP-1, through the activation of T2R, with consequent improvement of glucose homeostasis.     

Short communication: Promotion of glucagon-like peptide-2 secretion in dairy calves with a bioactive extract from Olea europaea

Diarrhea episodes in dairy calves involve profound alterations in the mechanism controlling gut barrier function that ultimately compromise intestinal permeability to macromolecules, including pathogenic bacteria. Intestinal dysfunction models suggest that a key element of intestinal adaptation during the neonatal phase is the nutrient-induced secretion of glucagon-like peptide (GLP)-2 and associated effects on mucosal cell proliferation, barrier function, and inflammatory response. Bioactive molecules found in Olea europaea have been shown to induce the release of regulatory peptides from model enteroendocrine cells. The ability to enhance GLP-2 secretion via the feeding of putative GLP-2 secretagogues is untested in newborn calves. The objectives of this study were to determine whether feeding a bioactive extract from Olea europaea (OBE) mixed in the milk replacer (1) can stimulate GLP-2 secretion beyond the response elicited by enteral nutrients and, thereby, (2) improve intestinal permeability and animal growth as well as (3) reduce the incidence of diarrhea in preweaning dairy calves. Holstein heifer calves (n = 60) were purchased, transported to the research facility, and blocked by body weight and total serum protein and assigned to 1 of 3 treatments. Treatments were control (CON), standard milk replacer (MR) and ad libitum starter; CON plus OBE added into MR at 30 mg/kg of body weight (OBE30); and CON plus OBE added into MR at 60 mg/kg of body weight (OBE60). The concentration of GLP-2 was measured at the end of wk 2. Intestinal permeability was measured at the onset of the study and the end of wk 2 and 6, with lactulose and d-mannitol as markers. Treatments did not affect calf growth and starter intake. Compared with CON, administration of OBE60 increased the nutrient-induced response in GLP-2 by about 1 fold and reduced MR intake during the second week of study. Throughout the study, however, all calves had compromised intestinal permeability and a high incidence of diarrhea. The GLP-2 response elicited by OBE60 did not improve intestinal permeability (lactulose-to-d-mannitol ratio) and incidence of diarrhea over the course of the preweaning period. The response in GLP-2 secretion to the administration of OBE reported herein warrants further research efforts to investigate the possibility of improving intestinal integrity through GLP-2 secretion in newborn calves.     

Effects of abomasal infusion of long-chain fatty acids on splanchnic metabolism of pancreatic and gut hormones in lactating dairy cows.

Pancreatic and gut peptide hormones are potential mediators of the reduction in dry matter intake (DMI) often observed in lactating dairy cows fed supplemental fat. We investigated the effects of 7-d abomasal infusions of a rapeseed and sunflower oil mixture providing mostly unsaturated long-chain fatty acids (LCFA) on arterial concentration and splanchnic (portal-drained viscera [PDV] and liver) metabolism of insulin, pancreatic (PAN) and gut (GUT) glucagon, glucagon-like peptide-1 (7-36) amide (GLP-1), and cholecystokinin (CCK) in six cows at 55 (ELAC) and 111 (MLAC) d postpartum. Plasma flow for the PDV and liver were greater in ELAC and increased by oil infusion. Arterial concentrations of insulin and PAN were greater in MLAC, whereas arterial concentrations of GLP-1 and CCK were greater in ELAC. Abomasal oil infusion increased arterial concentration of GUT and GLP-1 but decreased arterial insulin concentration. These differences in peripheral hormone concentration were due largely to changes in their net PDV release and (or) liver removal. In addition, net liver removal of PAN was increased by oil infusion. There was no effect of oil infusion on splanchnic metabolism or arterial concentration of CCK. Lower concentrations of CCK in MLAC were attributable to net liver removal, emphasizing the importance of liver metabolism in determining peripheral concentrations of gut and pancreatic peptide hormones. Results of this study suggest a role for products of proglucagon processing (PAN, GUT, and GLP-1) as mediators of the reduction in DMI caused by postruminal supply of LCFA.     

Effect of food ingredients on glucagon-like peptide-1 secretion in STC-1 and HuTu-80 cells

This study aims at identifying food ingredients that have potential to enhance satiety and therefore potentially can be used for preventing and treating obesity. To do so, effects of thirteen food ingredients on the secretion of gut satiety hormone glucagon-like peptide-1 (GLP-1) in enteroendocrine STC-1 and HuTu-80 cells were investigated. First, the effects of food ingredients on cell viability were investigated. This was done to determine if the individual ingredient affected cell viability, and in case so, to determine the ingredient concentration below which, the cell viability was unaffected. Enzyme-treated whey protein, palmitic acid, stearic acid, green tea extract, and hesperidin did not affect GLP-1 secretion. Functional soy protein, fractionated functional soy protein, acetylated monoglyceride, N-oleoylethanolamine, epigallocatechin-3-gallate, hesperetin, rosemary extract, and kale extract increased GLP-1 secretion in at least one cell line. However, the effects of the eight potent ingredients on GLP-1 secretion need to be further investigated in vivo.     

Sweet taste receptor expression in ruminant intestine and its activation by artificial sweeteners to regulate glucose absorption

Absorption of glucose from the lumen of the intestine into enterocytes is accomplished by sodium-glucose co-transporter 1 (SGLT1). In the majority of mammalian species, expression (this includes activity) of SGLT1 is upregulated in response to increased dietary monosaccharides. This regulatory pathway is initiated by sensing of luminal sugar by the gut-expressed sweet taste receptor. The objectives of our studies were to determine (1) if the ruminant intestine expresses the sweet taste receptor, which consists of two subunits [taste 1 receptor 2 (T1R2) and 3 (T1R3)], and other key signaling molecules required for SGLT1 upregulation in nonruminant intestines, and (2) whether T1R2-T1R3 sensing of artificial sweeteners induces release of glucagon-like peptide-2 (GLP-2) and enhances SGLT1 expression. We found that the small intestine of sheep and cattle express T1R2, T1R3, G-protein gustducin, and GLP-2 in enteroendocrine L-cells. Maintaining 110-d-old ruminating calves for 60 d on a diet containing a starter concentrate and the artificial sweetener Sucram (consisting of saccharin and neohesperidin dihydrochalcone; Pancosma SA, Geneva, Switzerland) enhances (1) Na⁺-dependent d-glucose uptake by over 3-fold, (2) villus height and crypt depth by 1.4- and 1.2-fold, and (3) maltase- and alkaline phosphatase-specific activity by 1.5-fold compared to calves maintained on the same diet without Sucram. No statistically significant differences were observed for rates of intestinal glucose uptake, villus height, crypt depth, or enzyme activities between 50-d-old milk-fed calves and calves maintained on the same diet containing Sucram. When adult cows were kept on a diet containing 80:20 ryegrass hay-to-concentrate supplemented with Sucram, more than a 7-fold increase in SGLT1 protein abundance was noted. Collectively, the data indicate that inclusion of this artificial sweetener enhances SGLT1 expression and mucosal growth in ruminant animals. Exposure of ruminant sheep intestinal segments to saccharin or neohesperidin dihydrochalcone evokes secretion of GLP-2, the gut hormone known to enhance intestinal glucose absorption and mucosal growth. Artificial sweeteners, such as Sucram, at small concentrations are potent activators of T1R2-T1R3 (600-fold > glucose). This, combined with oral bioavailability of T1R2-T1R3 and the understanding that artificial sweetener-induced receptor activation evokes GLP-2 release (thus leading to increased SGLT1 expression and mucosal growth), make this receptor a suitable target for dietary manipulation.     

Characterization of glucagon-like peptide 2 pathway member expression in bovine gastrointestinal tract

Glucagon-like peptide 2 (GLP-2), secreted by enteroendocrine cells, has several physiological effects on the intestine of monogastric species, including promotion of growth of intestinal epithelium, reduction of epithelial cell apoptosis, and enhancement of intestinal blood flow, nutrient absorption, and epithelial barrier function. The regulatory functions of GLP-2 in the ruminant gastrointestinal tract (GIT) have not been well studied. The objectives of this investigation were to characterize the mRNA expression of 4 members of the GLP-2 pathway throughout the bovine GIT, including (1) proglucagon (GCG), the parent peptide from which GLP-2 is derived through cleavage by prohormone convertase; (2) prohormone convertase (PCSK1); (3) GLP-2 receptor (GLP2R); and (4) dipeptidyl peptidase IV (DPP4), the enzyme that inactivates GLP-2. Gene expression was evaluated in rumen, reticulum, omasum, abomasum, duodenum, jejunum, ileum, cecum, and rectum collected at slaughter from prepubertal heifers, mature cows in early, mid, and late lactation, and nonlactating cows (n = 3 per stage) by a gene expression profiling assay. In addition, mRNA expression of 14 genes involved in nutrient transport, enzyme activity, blood flow, apoptosis, and proliferation were evaluated in the 9 GIT tissues for their association with GCG and GLP2R mRNA expression. Immunohistochemistry was used to localize GLP2R protein in tissues of the lower GIT. Results indicated that mRNA expression of GCG, PCSK1, GLP2R, and DPP4 varies across the 9 GIT tissues, with greatest expression in small and large intestines, and generally nondetectable levels in forestomachs. Expression of DPP4 and GLP2R mRNA varied by developmental stage or lactational state in intestinal tissues. Expression of GCG or GLP2R mRNA was correlated with molecular markers of proliferation, apoptosis, blood flow, enzyme activity, and urea transport, depending on the tissue examined, which suggests a potential for involvement of GLP-2 in these physiological processes in the ruminant GIT. The GLP2R protein was expressed in intestinal crypts of the bovine GIT, which is consistent with the distribution in monogastric species. Our findings support a functional role of the GLP-2 pathway in bovine GIT and the potential for use of GLP-2 as a therapy to improve intestinal function and nutrient absorption in ruminants.     

Massage and aroma therapy

Massage therapy has been shown to (1) facilitate growth and development; (2) reduce depression and anxiety and related stress hormones; (3) enhance sleep; (4) reduce pain; (5) reduce autoimmune disorders; and (6) enhance immune function. These effects have been noted in samples, for example, of preterm neonates, depressed children and adults, chronic pain conditions such as fibromyalgia and migraines, autoimmune disorders including asthma and diabetes and immune disorders including HIV and Cancer. Potential underlying mechanisms are enhanced parasympathetic activity (increased vagal tone) following massage therapy, decreased stress hormone (cortisol), increased serotonin (body's natural pain killer and antidepressant) and enhanced immune function leading to increased natural killer cell activity (front line of immune system, warding off viral and cancer cells). Aromatherapy has been noted to relax babies and adults and shift their EEG patterns in the direction of a more positive mood and heightened alertness.     

Direct correlationship between proton translocation and growth yield: an analysis of the respiratory chain of Bacillus stearothermophilus

Thermophilic bacilli contain cytochrome caa3-type cytochrome c oxidase as the main terminal oxidase in the respiratory chain. A mutant strain, named K-17, lacking cytochrome caa3 and exhibiting very low N,N,N',N'-tetramethyl-p-phenylene diamine oxidase activity, was isolated by random mutation from Bacillus stearothermophilus K1041 (Sakamoto, J. et al., FEMS Microbiol. Lett., 143, 151-158, 1996). Comparing this mutant with the parent strain K1041, we observed the following differences in energy-yielding properties. (i) K-17 gave an cell yield less than one half of that of the wild type, although the doubling time of K-17 was only a little slower than that of the parent strain. (ii) In cellular respiration, the H+/O ratio of K-17 was 2.9-3.1, while that of the wild type was 6.1-6.5. (iii) A low concentration of cyanide inhibited endogenous respiration of the wild-type cells partly with a concomitant reduction of the H+/O ratio to around 3, while it did not significantly affect the respiration rate and the H+/O ratio of the K-17 cells. (iv) Cytochrome bd-type quinol oxidase seemed to operate in the wild-type cells when a low concentration (below 0.5 mM) of cyanide was added, while this enzyme is the main terminal oxidase in K-17. The K-17 cells also contained cytochrome b(o/a)3-type cytochrome c-551 oxidase. These results demonstrated that the combination of the enzymes involved in the respiratory chain determines the H+/O ratios of the cell and consequently the growth yield of the bacteria.     

The effect of tube versus bottle feeding colostrum on immunoglobulin G absorption,abomasal emptying,and plasma hormone concentrations in newborn calves

The objective of this study was to determine if feeding colostrum to newborn calves through an esophageal tube, compared with a nipple bottle, would delay abomasal emptying, which would in turn decrease passive transfer of IgG and plasma glucose, insulin, and glucagon-like peptide (GLP) 1 and GLP-2 concentrations. Twenty newborn Holstein bull calves were fed 3 L of colostrum replacer (200 g of IgG) through either an esophageal tube or nipple bottle at 2 h after birth followed by feeding pooled whole milk every 12 h after birth. Acetaminophen was mixed into the colostrum meal as a marker for abomasal emptying. A jugular catheter was inserted 1 h after birth and blood was sampled frequently to analyze serum for IgG and acetaminophen and plasma for glucose, insulin, GLP-1, and GLP-2. Feeding method did not affect abomasal emptying, and as a result no treatment effect was present on serum IgG concentrations. Maximum concentration of serum IgG was 24.4 ± 0.40 mg/mL (± standard error), which was reached at 14.6 ± 1.88 h after the colostrum meal for both groups. Apparent efficiency of absorption at maximum concentration of IgG was 52.9%, indicating high efficiency of passive transfer of IgG for both treatments. Tube feeding increased glucose and insulin area under the curve before the first milk meal, most likely due to the decreased time to consume the colostrum meal. In addition, tube-fed calves consumed 0.5 ± 0.13 L more milk in their first milk meal than bottle-fed calves. No treatment effect on plasma concentrations of GLP-1 or GLP-2 was present, but both hormones increased after colostrum feeding. These findings confirm that there is no effect on absorption of IgG from colostrum when feeding good-quality colostrum at a volume of 3 L through either an esophageal tube or nipple bottle.