Effects of secretin and caerulein on enzymes of cultured pancreatic acinar cells

Summary We examined the effects of secretin (0 to 200 nM) and caerulein (0 to 100 nM) on rat pancreatic acinar cells cultured 0 to 48 h in serum-free medium. The effects of 100 nM secretin with 1 nM caerulein were also studied because secretin may potentiate the effects of caerulein. Cellular and media (secreted) lipase and amylase were analyzed as were cellular DNA and protein content. Cellular lipase and amylase activities significantly decreased (P<0.0001) over time in all treatment groups, whereas media amylase and lipase significantly increased (P<0.0001). Neither secretin nor caerulein affected cellular lipase or media amylase. However, secretin significantly increased (P<0.04) and caerulein tended to increase (P<0.08) media lipase in a dose-dependent manner. At 12 h, 10 nM secretin maximally increased media lipase (58%), suggesting that cultured acinar cells remain responsive to secretin in vitro. Caerulein, at all concentrations, significantly decreased (P<0.001) cellular amylase but exhibited a dose-dependent effect only at 24 h when 100 nM caerulein maximally decreased cellular amylase (34%). Secretin (100 nM) did not alter these effects of caerulein. These results support the proposed role of caerulein in the regulation of amylase but not a direct role of secretin in the regulation of lipase. This study was supported in part by grant RO1 DK32690 from the National Institutes of Health, Bethesda, MD.     

Neurotensin interacts with carbachol, secretin, and caerulein in the stimulation of the exocrine pancreas of the rat in vitro

In the present investigation the effect of neurotensin on pancreatic secretion of isolated pancreatic lobules from the rat was examined. We found a dose- and time-dependent stimulation of amylase release beginning with a concentration of 10(-9) M neurotensin. This response was potentiated by the cholinergic agonist carbachol, the gastrointestinal peptide secretin, and the CCK analogue caerulein. As we found neurotensin-immunoreactive nerves within the pancreas and as neurotensin-like immunoreactivity is present in the circulation (found previously), neurotensin may well be a further peptide taking part in the regulation of exocrine pancreatic secretion either as a hormone or a neurotransmitter. Neurotensin would then cooperate with cholinergic mechanisms, secretin, and CCK.     

The effect of neurotensin and secretin on gastric acid secretion and mucosal blood flow in man

Neurotensin stimulates pancreatic secretion directly and by potentiating the effect of secretin. Neurotensin also inhibits gastric secretion. Secretin inhibits gastric secretion as well, but whether it also interacts with neurotensin is not known. Secretin is known to inhibit gastric mucosal blood flow (GMBF). The effect of neurotensin on GMBF is not known. Acid secretion (triple lumen perfused orogastric tube) and GMBF ([14C]aminopyrine clearance) were therefore measured in 6 subjects during neurotensin, secretin and neurotensin plus secretin infusions. Neurotensin plus secretin reduced acid secretion by a median 130 (range 34-394) mumol/min which was significantly greater than either neurotensin at 36 (7-67) mumol/min or secretin 54 (20-347) mumol/min alone (P less than 0.05). This effect appeared independent of GMBF. Neurotensin plus secretin reduced GMBF by 14 (12-27) ml/min but not significantly more than neurotensin at 11 (3-20) ml/min or secretin 18 (2-27) ml/min alone. Further, there was no correlation between changes in acid output and GMBF during infusion of the peptides. We conclude that the inhibitory effects of neurotensin and secretin on gastric secretion are at least additive and together they may function as an 'enterogastrone'.     

Intestinal development and body growth of broiler chicks on diets supplemented with non-starch polysaccharides

The growth of broiler chicks and the mechanisms underlying responses to diets supplemented with commercial non-starch polysaccharides were evaluated. The supplements varied in viscosity and chemical structure and evaluation was conducted over two feeding periods.The viscosity of the four supplements tested ranged from 1.38 cP for alginic acid (AL) to over 2000 cP for guar gum (GG) and gum xanthan (GX). The whole diet followed a similar trend. The ileal digesta viscosity was significantly highest (P<0.001) in chicks that were fed the GX diet.Over a period of 7 days of feeding the diets, there was a significant reduction (P<0.001) in the final body weight and weight gain of chickens on diets supplemented with GG and GX. Supplementation with GG and GX also resulted in a deterioration (P<0.001) in FCR.The weight of the small intestine was higher (P<0.001) on the GG-supplemented diet than on the other diets while small intestinal fill was increased by the presence of GG and GX. There was no significant variation in the mucosal morphometry of birds on the different diets. Jejunal maltase and sucrase activities were highest (P<0.001) in chicks that were fed the AL-supplemented diet and lowest in chicks fed the GX-supplemented diet. The activity of aminopeptidase N in the ileum was stimulated (P<0.05) by GX. The uptake of l-tryptophan into brush-border membrane vesicles was unaffected by NSP supplement.After a second period of feeding the diets containing NSP at half the level present in the first period, final body weight and weight gain were significantly higher (P<0.001) on the gum arabic (GA)-supplemented diet than on the other diets. Absolute feed intake (P<0.05), feed intake per unit of initial body weight (P<0.001) and FCR (P<0.001) were significantly affected by the supplements, being higher in chicks on the GX-supplemented diet than on the other diets.The weight (P<0.001) and capacity (P<0.01) of the small intestine were highest in chicks on the GG- and GX-supplemented diets, respectively. The crypt depth of the jejunal mucosa was higher (P<0.01) in chickens on the GX-supplemented than in the other chickens. Ileal crypts were deepest and villi longest (P<0.05) in chicks on the GG- and GA-supplemented diets, respectively.Jejunal mucosal DNA (P<0.05) and RNA (P<0.001) contents of chicks were significantly increased by the GA-supplemented diet. In the ileum, RNA content (P<0.01) and RNA:DNA ratio (P<0.001) were reduced in chicks raised on the more viscous diets.Ileal maltase activity was also significantly higher (P<0.01) in chicks on the GX diet than in chicks on the other diets. l-Tryptophan uptake by ileal brush-border membranes was lowest (P<0.05) in chicks on the GA-supplemented diet.     

Effects of Synbiotic2000™ Forte on the Intestinal Motility and Interstitial Cells of Cajal in TBI Mouse Model

The main objective of this study was to investigate the effects of Synbiotic2000? Forte on the intestinal motility and interstitial cells of Cajal (ICC) in traumatic brain injury (TBI) mouse model. Kunming mice were randomly divided into sham operation group (S group), enteral nutrition group with TBI (E group), and Synbiotic2000? Forte group with TBI (P group). The contractile activity of the intestinal smooth muscle, densities and ultrastructure of the ICC, kit protein concentration, weight, and defecation of mice were monitored and analyzed. TBI markedly suppressed contractile activity of the intestinal smooth muscle (P < 0.01), which led to a reduction of defecation (P < 0.01) and weight (P < 0.01). However, application of Synbiotic2000? Forte significantly improved contractile activity of the small intestine (P < 0.01), which may be related to protective effects to the interstitial cells of Cajal, smooth muscle cells, and enteric neurons. TBI impaired ICC networks and densities (P < 0.01), events that were protected by the application of Synbiotic2000? Forte. Synbiotic2000? Forte may attenuate TBI-mediated inhibition of the kit protein pathway. Synbiotic2000? Forte may improve intestinal motility and protect the ICC in the TBI mouse. These findings provide a novel support for the application of Synbiotic2000? Forte in intestinal motility disturbance after TBI.     

Hepatic bile and pancreatic exocrine secretions evoked by gastrointestinal peptides in sheep

The secretory response of hepatic bile and exocrine pancreas to gastrointestinal peptides has been studied in chronically cannulated sheep. Pancreatic juice flow and protein output were evoked dose dependently by intraportal injection of secretin, CCK-8, caerulein, VIP and neurotensin. However, biliary secretion was evoked by only secretin. Biliary and pancreatic exocrine secretions were enhanced by delivered gastric juice into the duodenum as followed by the increased plasma concentration of immunoreactive secretin (IRS). Results suggest that secretin is the major peptide that regulates pancreatic exocrine secretion and hepatic bile production in the sheep.     

Stimulation of hepatocyte DNA synthesis by neurotensin

Epidermal growth factor and transforming growth factor alpha stimulated DNA synthesis in primary cultures of adult rat hepatocytes. Neurotensin amplified epidermal growth factor-stimulated or transforming growth factor alpha-stimulated DNA synthesis by three- to eightfold. Neurotensin by itself did not stimulate DNA synthesis. Amplification of DNA synthesis by neurotensin was observed as low as 10^?10 M, and it was increased in a dose-dependent manner with maximal effects at 10^–8 M. These results were obtained when hepatocytes were cultured in Williams' medium E, but not in Leibovitz L-15 medium, suggesting that a minor component(s) in the medium is required for hepatocytes to fully respond to neurotensin. Neurotensin effect on DNA synthesis was observed not only in normal rat hepatocytes but also in partially hepatectomized rat hepatocytes, although its effect was stronger in normal hepatocytes. Amplified DNA synthesis was inhibited by transforming growth factor β. Secondary mitogens (co-mitogens) such as insulin, vasopressin, or angiotensin II interacted additively with low concentrations of epidermal growth factor as well as with neurotensin. Neurotensin-related peptides such as kinetensin or neuromedin-N, which was released from blood plasma by pepsin digestion, did not have this amplifying effect on DNA synthesis at any concentrations tested. Neurotensin mRNA was found in several organs including brain and intestine, but not liver. These results suggest that neurotensin can be regarded as a new secondary mitogen and that it may be involved in cell proliferation, including regenerating liver as a gastrointestinal hormone and/or a neurotransmitter. © 1994 Wiley-Liss, Inc.     

A novel neurotensin/xenin fusion peptide enhances β-cell function and exhibits antidiabetic efficacy in high-fat fed mice

Neurotensin and xenin possess antidiabetic potential, mediated in part through augmentation of incretin hormone, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), action. In the present study, fragment peptides of neurotensin and xenin, acetyl-neurotensin and xenin-8-Gln, were fused together to create Ac-NT/XN-8-Gln. Following assessment of enzymatic stability, effects of Ac-NT/XN-8-Gln on in vitro β-cell function were studied. Subchronic antidiabetic efficacy of Ac-NT/XN-8-Gln alone, and in combination with the clinically approved GLP-1 receptor agonist exendin-4, was assessed in high-fat fed (HFF) mice. Ac-NT/XN-8-Gln was highly resistant to plasma enzyme degradation and induced dose-dependent insulin-releasing actions (P<0.05 to P<0.01) in BRIN-BD11 β-cells and isolated mouse islets. Ac-NT/XN-8-Gln augmented (P<0.001) the insulinotropic actions of GIP, while possessing independent β-cell proliferative (P<0.001) and anti-apoptotic (P<0.01) actions. Twice daily treatment of HFF mice with Ac-NT/XN-8-Gln for 32 days improved glycaemic control and circulating insulin, with benefits significantly enhanced by combined exendin-4 treatment. This was reflected by reduced body fat mass (P<0.001), improved circulating lipid profile (P<0.01) and reduced HbA1c concentrations (P<0.01) in the combined treatment group. Following an oral glucose challenge, glucose levels were markedly decreased (P<0.05) only in combination treatment group and superior to exendin-4 alone, with similar observations made in response to glucose plus GIP injection. The combined treatment group also presented with improved insulin sensitivity, decreased pancreatic insulin content as well as increased islet and β-cell areas. These data reveal that Ac-NT/XN-8-Gln is a biologically active neurotensin/xenin fusion peptide that displays prominent antidiabetic efficacy when administered together with exendin-4.     

Action of neurotensin on size, composition, and growth of pancreas and stomach in the rat

Since the gastrointestinal peptide neurotensin has a stimulatory effect on the secretion of the exocrine pancreas and an inhibitory effect on secretion and motility of the stomach, we investigated whether chronic parenteral administration of neurotensin would affect pancreatic and gastric growth. We therefore infused synthetic neurotensin subcutaneously (dose, 43 and 282 pmol X kg-1 X min-1) in 20 Wistar rats for 2 weeks using Alzet osmotic minipumps and compared pancreatic weight, DNA, RNA, protein, lipase, amylase, pancreatic polypeptide and insulin with these parameters in 10 control rats from the same litter with subcutaneously implanted plastic cylinders approximately the size of the minipumps. In another experiment, synthetic neurotensin (836 pmol X kg-1) was injected intraperitoneally three times a day for 3 days in 12 rats. Thereafter, we measured pancreatic DNA and in vitro incorporation of [3H]thymidine into pancreatic DNA. These effects were compared with the actions of caerulein and normal saline. Long term infusion of the high neurotensin dose induced an increase of pancreatic weight (control: 0.87 g, neurotensin: 1.02 g) and of DNA (control: 2.5 micrograms; neurotensin: 3.5 micrograms) and pancreatic polypeptide (control: 2.4 ng; neurotensin: 7.4 ng) contents, whereas pancreatic protein, RNA, amylase and lipase contents were not stimulated. In relation to DNA, these parameters even were significantly depressed. Insulin remained unchanged. Intraperitoneal injection of neurotensin induced an increase of pancreatic DNA content and stimulated [3H]thymidine incorporation into DNA (control: 11 000 dpm/g; neurotensin: 15 800 dpm/g pancreas). Moreover, long-term neurotensin infusion with the high dose led to a rise in protein concentration and an increase in the thickness of the gastric antrum; antral DNA concentration was insignificantly stimulated. Parenteral neurotensin in the doses and at the times administered, led therefore, to hyperplasia of the pancreas and induced growth of the gastric antrum. It is concluded that neurotensin can act as a trophic factor on pancreas and gastric antrum of the rat. It remains to be determined whether this represents a physiological effect of neurotensin.     

Estimating fermentative amino acid catabolism in the small intestine of growing pigs

Fermentative catabolism (FAAC) of dietary and endogenous amino acids (AA) in the small intestine contributes to loss of AA available for protein synthesis and body maintenance functions in pigs. A continuous isotope infusion study was performed to determine whole body urea flux, urea recycling and FAAC in the small intestine of ileal-cannulated growing pigs fed a control diet (CON, 18.6% CP; n=6), a high fibre diet with 12% added pectin (HF, 17.7% CP; n=4) or a low-protein diet (LP, 13.4% CP; n=6). ¹⁵N-ammonium chloride and ¹³C-urea were infused intragastrically and intravenously, respectively, for 4 days. Recovery of ammonia at the distal ileum was increased by feeding additional fibre when compared with the CON (P<0.05) but was not affected by dietary protein (0.24, 0.39 and 0.14 mmol nitrogen/kg BW/day for CON, HF and LP, respectively; P<0.05). Lowering protein intake reduced urea flux (25.3, 25.7 and 10.3 mmol nitrogen/kg BW/day; P<0.01), urinary urea excretion (14.4, 15.0 and 6.2 mmol N/kg BW/day; P<0.001) and urea recycling (12.1, 11.3 and 3.23 mmol nitrogen/kg BW/day; P<0.01) compared with CON. There was a rapid reduction in ¹⁵N-ammonia enrichment in digesta along the small intestine suggesting rapid absorption of ammonia before the distal ileum and lack of uniformity of enrichment in the digesta ammonia pool. A two-pool model was developed to determine possible value ranges for nitrogen flux in the small intestine assuming rapid absorption of ammonia. Maximum estimated FAAC based on this model was significantly lower when dietary protein content was decreased (32.9, 33.4 and 17.4 mmol nitrogen/kg BW/day; P<0.001). There was no impact of dietary fibre on estimates of small intestine nitrogen flux (P>0.05) compared with CON. The two-pool model developed in the present study allows for estimation of FAAC but still has limitations. Quantifying FAAC in the small intestine of pigs, as well as other non-ruminants and humans, offers a number of challenges but warrants further investigation.     

Effects of dodder total flavone on polycystic ovary syndrome rat models induced by DHEA combined HCG

AimsExplore the effects of dodder total flavone on polycystic ovary syndrome (PCOS) rat models induced by dehydroepiandrosterone (DHEA) combined human chorionic gonadotropin (HCG).MethodsExcept the blank group, the rest of the rats were injected with DHEA 6 mg/100 g on the back of the neck and 1.5 IU HCG each day, for 21 consecutive days. On the 16th day of modeling, vaginal smear was performed to select the model rats, which were randomly divided into model group, dacin-35 group, large, middle and small dose dodder total flavonoids groups, and given the medicine for three weeks. At the end of the last administration, take samples, so as to calculate the ovaries and uterus indexes, measure serum LH/FSH ratio, P, PRL and INS levels, fixed the uterus and pancreas in 10% formalin solution and stained with HE to observe the morphological changes of the organs. And measure the expression of TNF-α and IGF-l proteins in ovaries by immunohistochemistry.ResultsCompared with the blank group, ovarian and uterine indexes, serum LH/FSH ratio, serum PRL and INS levels, ovary TNF-α and IGF-l protein expression were significantly increased, and significant pathological changes were observed in the uterine and pancreatic tissues in model group (P < 0.01). While the serum P level decreased significantly (P < 0.01), Compared with the model group, the ovarian and uterine indexes, serum LH/FSH ratio, serum P, PRL and INS levels, ovary TNF-α protein expression were significantly decreased in large, middle and small dose dodder total flavonoids groups (P < 0.01); The expression of IGF-1 protein was decreased and uterus pathological changes were improved in different extents (P < 0.01 or P < 0.05), pancreas pathological changes were improved significantly (P < 0.01).ConclusionPCOS rat models was successfully replicated. Dodder total flavone can protect PCOS rats induced by DHEA combined HCG by different action pathways.     

Genetic analysis of an F2 intercross between two strains of Japanese quail provided evidence for quantitative trait loci affecting carcass composition and internal organs

The purpose of this study was to identify genomic regions, quantitative trait loci (QTL), affecting carcass traits on chromosome 1 in an F2 population of Japanese quail. For this purpose, two white and wild strains of Japanese quail (16 birds) were crossed reciprocally and F1 generation (34 birds) was created. The F2 generation was produced by intercrossing of the F1 birds. Phenotypic data including carcass weight, internal organs and carcass parts were collected on F2 animals (422 birds). The total mapping population (472 birds) was genotyped for 8 microsatellite markers on chromosome 1. QTL analysis was performed with interval mapping method applying the line-cross model. Significant QTL were identified for breast weight at 0 (P < 0.01), 172 (P < 0.05) and 206 (P < 0.01), carcass weight at 91 (P < 0.05), carcass fatness at 0 (P < 0.01), pre-stomach weight at 206 (P < 0.01) and uropygial weight gland at 197 (P < 0.01) cM on chromosome 1. There was also evidence for imprinted QTL affecting breast weight (P < 0.01) on chromosome 1. The proportion of the F2 phenotypic variation explained by the significant additive, dominance and imprinted QTL effects ranged from 1.0 to 7.3 %, 1.2 to 3.3 % and 1.4 to 2.2 %, respectively.     

Application of bioelectrical impedance analysis in prediction of light kid carcass and muscle chemical composition

Carcass data were collected from 24 kids (average live weight of 12.5±5.5 kg; range 4.5 to 22.4 kg) of Jarmelista Portuguese native breed, to evaluate bioelectrical impedance analysis (BIA) as a technique for prediction of light kid carcass and muscle chemical composition. Resistance (Rs, Ω) and reactance (Xc, Ω), were measured in the cold carcasses with a single frequency bioelectrical impedance analyzer and, together with impedance (Z, Ω), two electrical volume measurements (Vol_A and Vol_B, cm²/Ω), carcass cold weight (CCW), carcass compactness and several carcass linear measurements were fitted as independent variables to predict carcass composition by stepwise regression analysis. The amount of variation explained by Vol_A and Vol_B only reached a significant level (P<0.01 and P<0.05, respectively) for muscle weight, moisture, protein and fat-free soft tissue content, even so with low accuracy, with Vol_A providing the best results (0.326⩽R²⩽0.366). Quite differently, individual BIA parameters (Rs, Xc and Z) explained a very large amount of variation in dissectible carcass fat weight (0.814⩽R²⩽0.862; P<0.01). These individual BIA parameters also explained a large amount of variation in subcutaneous and intermuscular fat weights (respectively 0.749⩽R²⩽0.793 and 0.718⩽R²⩽0.760; P<0.01), and in muscle chemical fat weight (0.663⩽R²⩽0.684; P<0.01). Still significant but much lower was the variation in muscle, moisture, protein and fat-free soft tissue weights (0.344⩽R²⩽0.393; P<0.01) explained by BIA parameters. Still, the best models for estimation of muscle, moisture, protein and fat-free soft tissue weights included Rs in addition to CCW, and accounted for 97.1% to 99.8% (P<0.01) of the variation observed, with CCW by itself accounting for 97.0% to 99.6% (P<0.01) of that variation. Resistance was the only independent variable selected for the best model predicting subcutaneous fat weight. It was also selected for the best models predicting carcass fat weight (combined with carcass length, CL; R²=0.943; P<0.01) and intermuscular fat weight (combined with CCW; R²=0.945; P<0.01). The best model predicting muscle chemical fat weight combined CCW and Z, explaining 85.6% (P<0.01) of the variation observed. These results indicate BIA as a useful tool for prediction of light kids’ carcass composition.     

Histological and immunohistochemical studies of the endocrine cells of the gastrointestinal mucosa of the toad (Bufo regularis)

Using histological and immunhistochemical techniques, nine endocrine cell types were observed in the mucosa of the gastrointestinal tract of the toad, Bufo regularis, viz. enterochromaffin, somatostatin, glucagon, pancreatic polypeptide (PP), secretin, gastric inhibitory peptide (GIP), gastrin-C-terminal pentapeptide (GTPP), neurotensin and bombesin cells. The enterochromaffin cells were distributed throughout the gastrointestinal tract except the rectum. Somatostatin, glucagon, PP, secretin, GIP and GTPP cells were observed both in the stomach and in the small intestine. Neurotensin cells were seen only in the ileum and bombesin cells only in the pyloric and antral parts of the stomach. Immunostaining of consecutive sections did not reveal more than one polypeptide hormone in any of these cell types. It is concluded from the present results that the toad gastrointestinal mucosa contains endocrine cell types that are more or less homologous to those in the mammal alimentary tract, though some of them exhibit a different topographic distribution.     

Evaluation of protein supplementation for growing cattle fed grass silage-based diets: a meta-analysis

The objective of this meta-analysis was to develop empirical equations predicting growth responses of growing cattle to protein intake. Overall, the data set comprised 199 diets in 80 studies. The diets were mainly based on grass silage or grass silage partly or completely replaced by whole-crop silages or straw. The concentrate feeds consisted of cereal grains, fibrous by-products and protein supplements. The analyses were conducted both comprehensively for all studies and also separately for studies in which soybean meal (SBM; n=71 diets/28 studies), fish meal (FM; 27/12) and rapeseed meal (RSM; 74/35) were used as a protein supplement. Increasing dietary CP concentration increased (P<0.01) BW gain (BWG), but the responses were quantitatively small (1.4 g per 1 g/kg dry matter (DM) increase in dietary CP concentration). The BWG responses were not different for bulls v. steers and heifers (1.4 v. 1.3 g per 1 g/kg DM increase in dietary CP concentration) and for dairy v. beef breeds (1.2 v. 1.7 g per 1 g/kg, respectively). The effect of increased CP concentration declined (P<0.01) with increasing mean BW of the animals and with improved BWG of the control animals (the lowest CP diet in each study). The BWG responses to protein supplementation were not related to the CP concentration in the control diet. The BWG responses increased (P<0.05) with increased ammonia N concentration in silage N and declined marginally (P>0.10) with increasing proportion of concentrate in the diet. All protein supplements had a significant effect on BWG, but the effects were greater for RSM (P<0.01) and FM (P<0.05) than for SBM. Increasing dietary CP concentration improved (P<0.01) feed efficiency when expressed as BWG/kg DM intake, but decreased markedly when expressed as BWG/kg CP intake. Assuming CP concentration of 170 g/kg BW marginal efficiency of the utilisation of incremental CP intake was only 0.05. Increasing dietary CP concentration had no effects on carcass weight, dressing proportion or conformation score, but it increased (P<0.01) fat score. Owing to limited production responses, higher prices of protein supplements compared with cereal grains and possible increases the N and P emissions, there is generally no benefit from using protein supplementation for growing cattle fed grass silage-based diets, provided that the supply of rumen-degradable protein is not limiting digestion in the rumen.     

The amino acid composition of tissue protein is affected by the total sulfur amino acid supply in growing pigs

The factorial approach to assess the amino acid (AA) requirements of pigs is based on the assumption that the AA composition of body protein is constant. However, there are indications that this assumption may not be valid because the AA composition of body protein can be affected by the AA supply. The extent to which different tissues are affected by an AA deficiency is unknown. The objective of this study was to investigate the effect of feeding pig diets with a deficient or sufficient total sulfur AA supply (TSAA; Met+Cys) from 6 to 23 weeks of age on tissue composition and meat quality. The deficient diet (TSAA–) provided 24% Met : Lys and 51% TSAA : Lys on a standardized ileal digestible basis, which are 19% and 16% below the recommended requirements, respectively. The sufficient diet (TSAA+) provided 33% Met : Lys and 60% TSAA : Lys. Diets were offered slightly below the ad libitum feed intake capacity of the pigs. Pigs offered diet TSAA– had a lower average daily gain, lower weights of the longissimus dorsi (LM) and rhomboideus muscles (RM), and of selected skin sections (P<0.05). The weight of different sections of the small intestine and the liver was not affected by the diet. The protein content of the LM and RM decreased in pigs offered diet TSAA– (P<0.05), whereas the protein content of other tissues was not affected. The TSAA supply affected the AA composition (g/16 g N) of protein in all tissues, but the Met content was changed only in the liver (P<0.05). Pigs receiving diet TSAA– had a lower Cys content in the RM and in the distal jejunum and ileum (P<0.01). The deficient TSAA supply resulted in a lower carcass weight and higher muscle glycogen stores (P<0.05), but did not affect other meat quality traits. The results of this study indicate that the muscles, jejunum and ileum respond more to a prolonged AA deficiency than the liver. In addition, the observed changes in AA composition of tissue protein question the use of a constant AA profile of retained protein to assess AA requirements.     

Intake and digestion by lambs of dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and different levels of cracked corn grain

This study was carried out to evaluate intake, digestibility, ruminal fermentation, nitrogen (N) retention and ruminal microbial protein synthesis in lambs fed dwarf elephant grass (Pennisetum purpureum Schum. cv. Mott) hay or hay supplemented with urea and 0, 5, 10 or 15 g/kg of live weight (LW) of cracked corn grain. Ten lambs (mean LW of 28 ± 0.9 kg), housed in metabolic cages, were used in a double 5 × 5 Latin Square experiment. Except fibre intake and digestibility, which was higher, the intake and digestibility of the others feed components, as well as ruminal microbial protein synthesis and N retention were lower in non-supplemented lambs. Corn supplementation increased total dry matter (DM) (P<0.05), organic matter (OM), non-structural carbohydrate (NSC) and energy intake (P<0.01) but decreased total neutral detergent fibre (aNDFom) (P<0.01) intake, as well as OM and aNDFom intake from the hay (P<0.01). Apparent DM, OM and energy digestibility, as well as OM true digestibility (OMTD) increased (P<0.01), and aNDFom digestibility decreased linearly (P<0.01) as corn supplementation increased. Total N intake was not influenced but, apparent and true N digestibility, as well as urinary N excretion decreased (P<0.01), and ruminal microbial N entering the small intestine increased linearly (P<0.01) as corn supplementation increased. However, the efficiency of ruminal microbial protein synthesis was similar for all treatments. Mean ruminal pH values and ammonia N concentrations decreased linearly (P<0.01) with level of corn supplementation. Ammonia N and amino acid, as well as peptide concentrations in ruminal fluid were quadratically related (P<0.01) with the time after feeding. Corn supplementation had a linear additive effect on total dry matter and digestible energy intake, as well as on N retention, but a linear negative effect on hay intake and on fibre digestibility. However, decreased forage digestibility by animals was probably neither related to lower ruminal pH, which values were always higher than 7.0, nor related to ruminal sugar concentrations, which were similar for all treatments.     

Intestinal remodelling in mink fed with reduced protein content

Low protein intake occurs in humans in relation to diseases, starvation and post-operatively. Low-protein diets may affect the gastrointestinal structure and mechanical function. The aim was to study the passive biomechanical properties and tissue remodelling of the intestine in minks on reduced protein diets. Twenty-seven male minks were divided into three groups receiving different protein level in the diet for 6 weeks: High protein level (group H, 55% energy from protein), moderate protein level (group M, 30% energy from protein) and low protein level (group L, 15% energy from protein) (n=9 for each group). Ten centimetre long segments from duodenum, jejunum and ileum were excised at the end of the study period. The mechanical test was performed as a ramp distension experiment. The intestinal diameter and length, wall thickness, wall area and opening angle were obtained from digitized images of the intestinal segments at pre-selected pressures, no-load and zero-stress states, respectively. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed. The layer thickness was measured from intestinal histological images. No difference in body weight was found between groups at the start of the experiment. However, at the end of the experiment the body weight was smallest in group L (P=0.0003 and 0.0004 compared with groups H and M). Similarly, the wet weight per unit length, wall thickness and area were smallest in group L (P<0.05, P<0.01). The lowest wall thickness was found in the jejunum and ileum in group L (P<0.05), mainly due to decreased mucosa and submucosa thickness. The smallest opening angle and absolute values of residual strain were found in the jejunal segment in group L (P<0.05). No difference was observed for duodenal and ileal segments among the three groups. Feeding the low-protein diet shifted the stress–strain curves to the right for the circumferential direction, indicating the wall become softer in the circumferential direction. However, no significant difference was observed in the longitudinal direction for any of the intestinal segments. In conclusion, this study demonstrated that low-protein diet in minks induce histomorphometric and biomechanical remodelling of the intestine.     

Effect of 3:7 ratio of Astragalus total saponins and Curcumin on the diabetic nephropathy rats model

Objective

Study the effect of the 3:7 ratio of Astragalus total saponins and Curcumin on the model of diabetic nephropathy rats, and explore its mechanisms.

Effect of a new CCK-A receptor antagonist,dexloxiglumide, on the exocrine pancreas in the rat

The effect of dexloxiglumide, a new potent cholecystokinin (CCK) antagonist, on pancreatic enzyme secretion and growth was studied in the rat. Pancreatic exocrine secretion was studied both in vitro (isolated and perfused pancreatic segments) and in vivo (anaesthetized animals with cannulation of the common bile duct) whereas the trophic effect was investigated after short-term (7 days) administration of the CCK-agonist, caerulein, or camostate (a potent trypsin inhibitor), with or without dexloxiglumide. CCK-8 stimulated amylase release from in vitro pancreatic segments in a concentration-dependent manner. Dexloxiglumide displaced the concentration response curves to CCK-8 to the right without affecting the maximum response, suggesting a competitive antagonism. The Schild plot analysis of data gave a straight line with a slope (0.90±0.36) not significantly different from unity. The calculated pA₂ for dexloxiglumide was 6.41 ± 0.38. In vivo experiments confirmed results from in vitro studies since intravenous dexloxiglumide reduced pancreatic exocrine secretion induced by submaximal CCK-8 stimulation (0.5 nmol/kg/h) in a dose-dependent manner, the ID₅₀ being 0.64 mg/kg. Both exogenous and endogenous (released by camostate) CCK increased the weight of the pancreas, the total pancreatic protein and DNA, trypsin and amylase content. Dexloxiglumide (25 mg/kg), administered together with caerulein (1 μg/kg), reduced the peptide-induced increase in pancreatic weight, protein and enzyme content. Similarly, when dexloxiglumide was given together with camostate (200 mg/kg), all the observed changes were reduced by concomitant administration of the antagonist. These results demonstrate the ability of dexloxiglumide to antagonize the effects of CCK on pancreatic secretion and growth, suggesting that this compound is a potent and selective antagonist of CCK-A-receptors in the pancreas.