Effects of dietary amylose/amylopectin ratio and amylase on growth performance, energy and starch digestibility, and digestive enzymes in broilers.

This study was conducted to investigate the effects of dietary amylose/amylopectin (AM/AP) ratio and amylase on growth performance, apparent digestibility of energy and starch, serum biochemical index, and digestive enzymes. The experiment used a 4 × 3 factor design, and 960 one-day-old Arbor Acres (AA) broilers were randomly divided into 12 groups fed diets containing different AM/AP ratio of 0.11, 0.23, 0.35 and 0.47 and combined with 0, 3,000 and 6,000 U/kg amylase. Results showed that 0.23-0.35 AM/AP ratio increased growth performance, while dietary addition of 6,000 U/kg amylase significantly reduced average daily weight gain in broilers. The energy digestibility was significantly reduced along with the increase of dietary AM/AP ratio and in the 6,000 U/Kg amylase-supplemented groups. The digestibility of starch also decreased significantly with the increase of dietary AM/AP ratio, but high dose (6,000 U/Kg) of amylase increased. High AM/AP diet reduced serum insulin concentration, which was increased in amylase-supplemented groups. Furthermore, exogenous amylase increased amylase activity in the jejunal chyme. In conclusion, dietary 0.23-0.35 AM/AP ratio was suggested to maintain a higher growth performance in broilers and high AM/AP ratio diets reduced energy and starch digestibility and serum insulin concentration, which was reversed by dietary amylase.

Stability and bioavailability of vitamin D3 encapsulated in composite gels of whey protein isolate and lotus root amylopectin.

A gel delivery system was developed in the present work using whey protein isolate and lotus root amylopectin via regulating pH. The texture, thermodynamics, rheology and microstructure of gels were evaluated. Results showed that pH at 7.0 induced a more compact and stable gel structure than other pH. The composite gel formed at pH 7.0 was accordingly employed to encapsulate vitamin D3. Results exhibited that the encapsulation of composite gel of whey protein isolate and lotus root amylopectin could enhance the storage stability of vitamin D3 and protect vitamin D3 from photochemical degradation. Moreover, this encapsulation could control the release of vitamin D3 in simulated intestinal fluid. Animal experiments exhibited that the bioavailability was significantly increased after vitamin D3 was encapsulated by the composite gel. This work indicated that the whey protein isolate-lotus root amylopectin gel is a good delivery system to improve the stability and bioavailability of vitamin D3.

Effects of dietary amylose and amylopectin ratio on growth performance, meat quality, postmortem glycolysis and muscle fibre type transformation of finishing pigs.

The present study was conducted to investigate the effects of dietary amylose and amylopectin ratio on growth performance, meat quality, postmortem glycolysis and muscle fibre type transformation of finishing pigs. Twenty-four barrows (Duroc × Landrace × Yorkshire) with an average initial body weight of 61.7 ± 2.01 kg were randomly assigned to four dietary treatments with amylose: amylopectin ratios of 1:1 (HD), 1:2 (MD), 1:3 (CD) and 1:4 (LD). The results showed that the average daily weight gain of finishing pigs tended to reduce with the ratio of amylose and amylopectin decreased (p = 0.09). Diet LD increased the pH24h value and decreased the shear force in longissimus dorsi (LM) compared with diet HD (p < 0.05). Diet LD decreased the lactate content and the HK-2 mRNA abundance and increased the mRNA abundance of ATP5B in LM compared with diet HD (p < 0.05). Higher mRNA abundance of MyHC I and lesser abundance of MyHC IIb in LM were found in pigs fed diet CD and LD than those fed diet HD (p < 0.05). Furthermore, pigs fed diet LD had higher mRNA abundances of PGC-1α and PPAR δ in LM than other groups (p < 0.05). These results suggested that diet with low amylose and amylopectin ratio could improve meat quality of finishing pigs via delaying muscle glycolysis capacity and shifting muscle fibre types.

Long-term ingestion of low amylose/amylopectin ratio diet affects aspects of meat quality by changing muscle fibre characteristics in growing-finishing pigs.

Amylose plays important role in body health. It is controversial whether changing dietary amylose/amylopectin ratio (DAR) will improve meat quality in growing-finishing pigs. A total of 48 Duroc × Landrace × Large White castrated male pigs (initial body weight 49.8 ± 2.8 kg) were randomly allotted to two treatments, and fed ad libitum either with a low DAR diet (LR, amylose/amylopectin: 12/88) or a high DAR diet (HR, amylose/amylopectin: 30/70) for 68 days. Feed intake was recorded every day, body weight was weighed at 46th and 68th day to calculate average daily gain (ADG), average daily feed intake (ADFI) and Feed:gain ratio. Blood was collected at -30 min (fasting 12 hr), 60, 90, 120, 180 min postprandial at 64th day and then serum was obtained by centrifugation of blood at 1,500× g at 4°C. After pigs were slaughtered, samples such as longissimus dorsi, iliopsoas and semitendinosus were collected. Density, diameter and types of muscle fibres were analysed. Results showed that ADG, ADFI, Feed:Gain ratio, cross-sectional area of longissimus dorsi muscle, backfat thickness, colour scores were not affected by DAR. Ingestion of LR diet increased the fasting glucose (p < 0.05) and insulin (p < 0.05) concentrations in serum. The drip loss and firmness were decreased significantly in LR vs. HR animals (p < 0.05). Densities of muscle fibre in longissimus dorsi, iliopsoas and semitendinosus were greater in LR pigs (p < 0.05). Moreover, ingestion of LR diet significantly increased myosin heavy chain (MyHC) IIa mRNA level and decreased MyHC IIb gene expression in longissimus dorsi muscle (LM) (p < 0.05). Therefore, intake of diet low in amylose/amylopectin ratio induces a better meat quality (lower drip loss and lower firmness), which could attribute to smaller myofibres, a shift to slower and/or more oxidative fibres.

The effect of dietary amylose/amylopectin ratio on serum and hepatic lipid content and its molecular mechanisms in growing-finishing pigs.

This study was conducted to investigate the effects of dietary amylose/amylopectin ratio (DAR) on serum and hepatic lipid content, luminal short-chain fatty acid (SCFA) concentrations, and the expression of host genes involved in fat and glucose metabolism in liver and mucosa in growing-finishing pigs. Forty-eight Duroc × Landrace × Large White pigs (49.8 ± 2.8 kg) were randomly allocated to low amylose/amylopectin ratio (LR) and high amylose/amylopectin ratio (HR) groups, each group consisting of six replicates (pen) with four pigs per pen. The DAR was 12/88 for LR and 30/70 for HR. Experiment lasted for 67 days. Results showed that, compared with HR group, ingestion of LR significantly increased the liver total lipid and cholesterol concentration (p < .05) and decreased the serum LDL-C concentration (p < .05). The concentration of propionate, butyrate and total SCFAs in caecum digesta was significantly lower in LR group than in HR group (p < .05). We observed a significant increase in glucose transporter 2 (GLUT2), sodium-dependent glucose transporter 1 (SGLT1) gene expression in LR-fed pigs in the jejunum mucosa (p < .01). A decrease in Na+-coupled monocarboxylate transporter (SMCT1) and free fatty acid receptor 3 (FFAR3) expression was found in the ileum mucosa with LR group (p < .05). Ingestion of LR diet significantly decreased the hexokinase (p < .01) and tend to decrease the pyruvate kinase (p = .050) activities in the liver. Meanwhile, the present results indicated that ingestion of LR diet significantly increased the transcription of gluconeogenesis and lipogenic genes such as forkhead box O1 (FOXO1), fatty acid synthetase3 (FAS3) (p < .05). These findings demonstrated that high amylopectin has harmful effects on hepatic lipid deposit through the modulation of the liver Foxo1 signalling and should be avoided from one's diet.

Bioequivalence decision for nanoparticular iron complex drugs for parenteral administration based on their disposition.

Although parenteral iron products have been established to medicinal use decades before, their structure and pharmacokinetic properties are not fully characterized yet. With its' second reflection paper on intravenous iron-based nano-colloidal products (EMA/CHMP/SWP/620008/2012) the European Medicine Agency provided an extensive catalogue of methods for quality, non-clinical and pharmacokinetic studies for the comparison of nano-sized iron products to an originator (EMA, 2015). For iron distribution studies, the reflection paper assumed the use of rodents. In our tests, we used a turkey fetus model to investigate time dependent tissue concentrations in pharmacological and toxicological relevant tissues liver, heart and kidney. We found turkey embryos to be a suitable alternative to rodents with high discriminatory sensitivity. Clear differences were found between equimolar doses of iron products with hydroxyethyl amylopectin, sucrose, dextrane and carboxymaltose shell. A linear dose dependency for the tissue accumulation was also demonstrated.

Dietary starch types affect liver nutrient metabolism of finishing pigs.

This study aimed to evaluate the effect of different starch types on liver nutrient metabolism of finishing pigs. In all ninety barrows were randomly allocated to three diets with five replicates of six pigs, containing purified waxy maize starch (WMS), non-waxy maize starch (NMS) and pea starch (PS) (the amylose to amylopectin ratios were 0·07, 0·19 and 0·28, respectively). After 28 d of treatments, two per pen (close to the average body weight of the pen) were weighed individually, slaughtered and liver samples were collected. Compared with the WMS diet, the PS diet decreased the activities of glycogen phosphorylase, phosphoenolpyruvate carboxykinase and the expression of phosphoenolpyruvate carboxykinase 1 in liver (P0·05). Compared with the WMS diet, the PS diet reduced the expressions of glutamate dehydrogenase and carbamoyl phosphate synthetase 1 in liver (P<0·05). PS diet decreased the expression of the insulin receptor, and increased the expressions of mammalian target of rapamycin complex 1 and ribosomal protein S6 kinase ß-1 in liver compared with the WMS diet (P<0·05). These findings indicated that the diet with higher amylose content could down-regulate gluconeogenesis, and cause less fat deposition and more protein deposition by affecting the insulin/PI3K/protein kinase B signalling pathway in liver of finishing pigs.

Effects of dietary starch types on growth performance, meat quality and myofibre type of finishing pigs.

To investigate the effects of dietary starch types on growth performance and meat quality of finishing pigs, ninety barrows (68.0±2.0kg) were randomly allotted to three experimental diets with five replicates of six pigs, containing pure waxy maize starch (WMS), nonwaxy maize starch (NMS) and pea starch (PS) (amylose/amylopectin were 0.07, 0.19 and 0.28 respectively). Compared with WMS diet, PS diet increased the average daily gain, loin eye area, pH45 value, NMR transverse relaxation (T2)2 peak area ratio and sarcoplasmic protein solubility, decreased the feed to gain ratio, back fat, drip loss, cooking loss and T23 peak area ratio (P<0.05). Moreover, PS diet increased the myosin heavy-chain (MyHC)-I and IIa levels, decreased the MyHC-IIb level, decreased the miR23a level and increased its target gene level, increased the miR499 level and decreased its target gene level (P<0.05). Diet with high amylose content might be beneficial to the growth performance and meat quality of finishing pigs.

Effects of an amylopectin and chromium complex on the anabolic response to a suboptimal dose of whey protein.

BACKGROUND: Previous research has demonstrated the permissive effect of insulin on muscle protein kinetics, and the enhanced insulin sensitizing effect of chromium. In the presence of adequate whole protein and/or essential amino acids (EAA), insulin has a stimulatory effect on muscle protein synthesis, whereas in conditions of lower blood EAA concentrations, insulin has an inhibitory effect on protein breakdown. In this study, we determined the effect of an amylopectin/chromium (ACr) complex on changes in plasma concentrations of EAA, insulin, glucose, and the fractional rate of muscle protein synthesis (FSR). METHODS: Using a double-blind, cross-over design, ten subjects (six men, four women) consumed 6 g whey protein + 2 g of the amylopectin-chromium complex (WPACr) or 6 g whey protein (WP) after an overnight fast. FSR was measured using a primed, continuous infusion of ring-d5-phenylalanine with serial muscle biopsies performed at 2, 4, and 8 h. Plasma EAA and insulin were assayed by ion-exchange chromatography and ELISA, respectively. After the biopsy at 4 h, subjects ingested their respective supplement, completed eight sets of bilateral isotonic leg extensions at 80% of their estimated 1-RM, and a final biopsy was obtained 4 h later. RESULTS: Both trials increased EAA similarly, with peak levels noted 30 min after ingestion. Insulin tended (p = 0.09) to be higher in the WPACr trial. Paired samples t-tests using baseline and 4-h post-ingestion FSR data separately for each group revealed significant increases in the WPACr group (+0.0197%/h, p = 0.0004) and no difference in the WP group (+0.01215%/hr, p = 0.23). Independent t-tests confirmed significant (p = 0.045) differences in post-treatment FSR between trials. CONCLUSIONS: These data indicate that the addition of ACr to a 6 g dose of whey protein (WPACr) increases the FSR response beyond what is seen with a suboptimal dose of whey protein alone.

Responses in ileal and cecal bacteria to low and high amylose/amylopectin ratio diets in growing pigs.

Dietary starch that escapes digestion in the small intestine may serve as a carbon source for bacterial fermentation in the distal intestine. This study aimed to compare the bacterial community in the ileal and cecal digesta of growing pigs fed diets with low (0.14, LR pigs) and high (0.43, HR pigs) amylose/amylopectin ratio. Pyrosequencing based on MiSeq 2000 platform showed that in ileum digesta, Bacteroidetes of LR pigs was markedly higher than that in HR pigs (P < 0.05). Megasphaera and Prevotella were the two most predominant genera in LR pigs, and Prevotella was significantly higher in LR pigs than in HR pigs (P < 0.05). Prevotella was predominant in cecal samples from both LR and HR pigs, although no significant differences were found between the two groups. In the ileum, Megasphaera elsdenii and Mitsuokella multacida were significantly (P < 0.01) higher in LR pigs along with an increase of acetate and butyrate concentrations. Halomonas pacifica, Escherichia fergusonii, and Actinobacillus minor which belong to class Gammaproteobacteria were significantly lower (P < 0.01) in HR pigs with a significant increase (P < 0.01) of Lactobacillus acetotolerans-like bacteria. Therefore, the changed bacterial community may lead to a transformation of microbial function, such as the alteration of fermentation mode which is showed on the change of microbial metabolites like the concentration of short-chain fatty acids (SCFAs), to a response to the switch of dietary composition, and in turn, to help host absorb and utilize nutrients efficiently. The increase of dietary amylose induced the reduction of conditioned pathogens which may probably be due to the increase of some probiotics such as Lactobacillus, thus reducing the risk of intestinal disease.

Effect of dietary amylose/amylopectin ratio on growth performance, carcass traits, and meat quality in finishing pigs.

The present study was conducted to evaluate the effect of dietary amylose/amylopectin ratio (DAR) on body health and meat quality in finishing pigs. A total of forty-eight DLY pigs (initial body weight of 74.9±5.0kg) were randomly allotted to two treatments, and fed either with LR (DAR: 12/88) or HR (DAR: 30/70) diet. Results showed that ingestion of a HR diet not only decreased the triacylglycerol and cholesterol concentrations in plasma (P<0.05), but also reduced the lipid contents in liver (P<0.05). Interestingly, ingestion of a HR diet tended to reduce the intramuscular fat content (P=0.06), and significantly increased the firmness (P<0.05) and loin-eye area (P<0.01). Moreover, ingestion of a HR diet significantly decreased the levels of MyHC I (P<0.05), and elevated the levels of MyHCIIb (P<0.05) gene expression in longissimus dorsi. Ingestion of a HR diet has resulted in down-regulation of the FAS3 gene in liver and longissimus dorsi (P<0.05). These findings suggested that a HR diet is helpful to reduce the lipogenesis both in liver and muscle.

Effects of dietary amylose/amylopectin ratio on growth performance, feed utilization, digestive enzymes, and postprandial metabolic responses in juvenile obscure puffer Takifugu obscurus.

The effect of dietary amylose/amylopectin (AM/AP) ratio on growth, feed utilization, digestive enzyme activities, plasma parameters, and postprandial blood glucose responses was evaluated in juvenile obscure puffer, Takifugu obscurus. Five isonitrogenous (430 g kg(-1) crude protein) and isolipidic (90 g kg(-1) crude lipid) diets containing an equal starch level (250 g kg(-1) starch) with different AM/AP ratio diets of 0/25, 3/22, 6/19, 9/16 and 12/13 were formulated. Each experimental diet was fed to triplicate groups (25 fish per tank), twice daily during a period of 60 days. After the growth trial, a postprandial blood response test was carried out. Fish fed diet 6/19 showed best growth, feed efficiency and protein efficiency ratio. Hepatosomatic index, plasma total cholesterol concentration, liver glycogen and lipid content, and gluconokinase, pyruvate kinase and fructose-1,6-bisphosphatase activities were lower in fish fed highest AM/AP diet (12/13) than in fish fed the low-amylose diets. Activities of liver and intestinal trypsin in fish fed diet 3/22 and diet 6/19 were higher than in fish fed diet 9/16 and diet 12/13. Activities of liver and intestinal amylase and intestinal lipase, and starch digestibility were negatively correlated with dietary AM/AP ratio. Fish fed diet 3/22 and diet 6/19 showed higher plasma total amino acid concentration than fish fed the other diets, while plasma urea nitrogen concentration and activities of alanine aminotransferase and aspartate aminotransferase showed the opposite trend. Equal values were found for viscerosomatic index and condition factor, whole body and muscle composition, plasma high-density and low-density lipoprotein cholesterol concentrations, and activities of lipase and hexokinase and glucose-6-phosphatase in liver. Postprandial plasma glucose and triglyceride peak value of fish fed diet 12/13 were lower than in fish fed the low-amylose diets, and the peak time of plasma glucose was later than in fish fed the other diets. Plasma glucose and triglyceride concentrations showed a significant difference at 2 and 4 h after a meal and varied between dietary treatments. According to regression analysis of weight gain against dietary AM/AP ratio, the optimum dietary AM/AP ratio for maximum growth of obscure puffer was 0.25. The present result indicates that dietary AM/AP ratio could affect growth performance and feed utilization, some plasma parameters, digestive enzyme as well as hepatic glucose metabolic enzyme activities in juvenile obscure puffer.

Crescimento de juvenis de jundiá (Rhamdia quelen) com diferentes proporções de amilose: amilopectina na dieta / Growth of jundiá juveniles (Rhamdia quelen) with different proportions of amylose:amylopectin in diet

Crescimento e características de carcaça do jundiá (Rhamdia quelen) foram avaliados após 60 dias de alimentação com diferentes proporções de amilose:amilopectina na dieta. Foram criados 240 peixes (peso inicial de 34,3±4,3g) em sistema de recirculação de água constituído de 12 unidades experimentais de 280L. Foram testadas três dietas com as proporções amilose:amilopectina de: T417 = com 26 por cento de amilose, T416 = com 16 por cento de amilose e TMOCHI = com 0 por cento de amilose. Os peixes foram alimentados duas vezes por dia, às 8h e 30min e às 16 horas. A cada 15 dias, foram feitas biometrias para ajuste da quantidade de alimento ofertado. A proporção amilose:amilopectina no amido das dietas não influenciou o crescimento, os rendimentos de carcaça e a composição corporal dos peixes. Conclui-se que o jundiá tem potencial para utilizar fontes de amido compostas por até 26 por cento de amilose sem alterar a digestibilidade dos nutrientes e a deposição de gordura.

The growth and carcass traits of jundiá (Rhamdia quelen) after 60 days being fed with different amylose:amylopectin ratio in diet were evaluated. Two hundred and forty fish (initial weight of 34.3±4.3g) were raised in water re-use system with 12 units of 280L. Three diets were tested with amylose:amylopectin ratios: T417 = 26 percent amylose, T416 = 16 percent amylose and TMOCHI = 0 percent amylose. The fish were fed twice a day at 8:30 and 16:00h. Every 15 days the amount of food offered was ajusted. The amylose:amylopectin ratio in the starch of the diet did not affect growth, carcass and body composition of fish. This demonstrates that the jundiá has the potential to use starchy sources consisting of up to 26 percent amylose without altering the digestibility of nutrients and fat deposition.

A high-amylopectin diet caused hepatic steatosis associated with more lipogenic enzymes and increased serum insulin concentration.

Starch is the major energy source for monogastric mammals and humans. The present study was conducted to evaluate the liver metabolic responses of weaned pigs fed with different dietary starches. A total of sixteen weaned pigs were fed with two experimental diets containing either cassava starch (CS, 80 % amylopectin and 20 % amylose) or maize starch (70 % amylopectin and 30 % amylose). The present results showed that the growth performance was not affected by different dietary starches (P>0·05). However, ingestion of CS not only increased the lipid content in liver tissues, but also elevated the concentrations of serum cholesterol and insulin (P < 0·05). The metabolic responses induced by CS were associated with more lipogenic enzymes such as fatty acid synthase and 3-hydroxy-3-methyl-glutaryl-CoA reductase in liver (P < 0·05). Real-time PCR quantification for lipid metabolic genes indicated that ingestion of CS not only up-regulated the expression of these lipogenic genes, but also decreased the expression of lipolytic genes. These results suggested that the metabolic responses of weaned pigs fed with different dietary starches may vary widely depending on their composition, and ingestion of starches that are high in amylopectin may produce a stronger insulinaemic response and lead to an up-regulation of lipogenesis in the liver.

Metabolic and transcriptomic responses of weaned pigs induced by different dietary amylose and amylopectin ratio.

Starch is one of the major dietary energy sources for mammals. However, the nutritional value of starch largely depends on its amylose and amylopectin ratio. In this study, the overall metabolic and transcriptomic responses of weaned pigs fed with different dietary starches were assessed. Sixteen weaned pigs were randomly allotted to two experimental diets containing either of pure cassava starch (CS) or maize starch (MS) as the sole energy source (the amylose-amylopectin ratio were 0.25 and 0.43, respectively). Results indicated that the body weight gain was not affected by different dietary starches. However, a moderate fatty liver was observed in CS-fed group. Long-term ingestion of CS not only increased the total liver fat content, but significantly elevated the liver triglyceride and cholesterol content (P<0.05). In addition, the serum insulin and cholesterol concentrations were both elevated in CS-fed group (P<0.05). Microarray analysis led to the identification of 648 genes differentially expressed in liver (P<0.05), and a lot of them were involved in lipid and carbohydrate metabolism. Additionally, pathway analysis indicated that both the insulin and PPAR signaling pathways were acutely affected by dietary amylose-amylopectin ratio. Long-term ingestion of CS activated the transcription of lipogenic genes such as hmgr and fasn, but decreased the expression of lipolytic genes such as aox1, ppara and fbp. The microarray results correlated well with the measurements of several key enzymes involved in hepatic lipid metabolism. Our results suggested that both the metabolic and transcriptomic responses of weaned pigs were tightly regulated by dietary starch composition, and a high amylose ratio starch (i.e MS) may be more healthful for mammals as the long-term energy source by down-regulation of hepatic lipogenesis and steroidogenesis.

Hemostatic efficacy of modified amylopectin powder in a lethal porcine model of extremity arterial injury.

STUDY OBJECTIVE: Rapid hemostasis is crucial in controlling severe extremity hemorrhage. Our objective is to evaluate the hemostatic efficacy of a newly modified amylopectin powder in a model of severe extremity arterial hemorrhage. METHODS: Anesthetized pigs underwent severe, reproducible femoral artery injuries. Animals were randomized (nonblinded) to either modified amylopectin powder (n=10) or standard gauze application (n=6). Each hemostatic agent was applied through a pool of blood with manual compression for 3-minute intervals until hemostasis was achieved. Fluid resuscitation was infused as necessary to reestablish a mean arterial pressure within at least 80% of the preinjury mean arterial pressure if possible. The primary measured outcome was total blood loss. Secondary endpoints were survival, time to hemostasis, resuscitation mean arterial pressure, and resuscitation volume. RESULTS: Pretreatment blood losses were similar in both groups. Median (absolute average deviation of the median) posttreatment blood loss was significantly less in the modified amylopectin powder group than in the gauze group, 275 (108) mL versus 1,312 (171) mL. Resuscitation mean arterial pressure at 180 minutes after injury was 68% of preinjury mean arterial pressure in the modified amylopectin powder group and undetectable in all control animals. Fluid volume required for resuscitation was 1,962 (258) mL in the modified amylopectin powder group and 2,875 (150) mL in the gauze group. Time to hemostasis was 9.0 (2.1) minutes in the modified amylopectin powder group. Hemostasis was not achieved in any animal in the gauze group. Survival was 100% in the modified amylopectin powder group, whereas no animals survived in the gauze group. CONCLUSION: Modified amylopectin powder demonstrates the ability to control major vascular bleeding in a lethal arterial injury model during a 3-hour period.

Apparent mineral retention is similar in control and hyperinsulinemic men after consumption of high amylose cornstarch.

The effects on apparent mineral retention after long-term consumption of a high amylose diet containing 30 g resistant starch (RS) were investigated in 10 control and 14 hyperinsulinemic men. Subjects consumed products (bread, muffins, cookies, corn flakes and cheese puffs) made with standard (70% amylopectin, 30% amylose; AP) or high amylose (70% amylose, 30% amylopectin; AM) cornstarch for two 14-wk periods in a crossover pattern. Starch products replaced usual starches in the habitual diet for 10 wk followed by 4 wk of consuming the controlled diets. During wk 12, all urine, feces and duplicate foods were collected for 7 d. Urinary chromium losses after a glucose tolerance test or 24-h collections of the hyperinsulinemic and control subjects did not differ and were not altered by diet. Except for zinc, the two subject types did not differ significantly in apparent mineral balance. Apparent retentions of calcium and magnesium were not significantly affected by diet (AM vs. AP) or type-by-diet interaction. Apparent iron retention tended to be greater after AM than AP consumption (P < 0.09). Apparent copper retention was greater after consuming AP than after AM (P < 0.02), whereas apparent zinc retention was greater after consuming AM than after AP (P < 0.018). Zinc also showed a significant type-by-diet interaction (P < 0.034) with control subjects retaining less zinc after consuming AP than after AM. In summary, a high amylose cornstarch diet containing 30 g RS could be consumed long term without markedly affecting, and possibly enhancing, retention of some minerals.

Amylopectin as a subcoating material improves the acidic resistance of enteric-coated pellets containing a freely soluble drug.

The effect of an aqueous amylopectin subcoating on the acidic resistance and dissolution behaviour of enteric-coated pellets was studied. Freely water-soluble riboflavin sodium phosphate (RSP) was used as a model drug, and microcrystalline cellulose (MCC) and lactose as fillers in the pellet cores. The pellets were subcoated with 5% aqueous amylopectin solution or with 5% hydroxypropyl methylcellulose (HPMC) solution, and subsequently film-coated with aqueous dispersion of cellulose acetate phthalate (CAP). Drug release of enteric-coated pellets was investigated by confocal laser scanning microscopy (CLSM). Dissolution tests showed that amylopectin subcoating improved the acidic resistance of the enteric-coated pellets in 0.1 N hydrochloric acid (HCl) compared with HPMC subcoating. As the amylopectin subcoating load was increased to 4% and the aqueous CAP coating load to 35%, the coated pellets resisted in 0.1 N HCl solution for approximately 1 h (the amount of drug released was below 10%), and they dissolved in the SIF without enzymes in less than 10 min. Confocal microscopy images and profiles of mean fluorescence intensities of RSP (obtained in the range of the interface of the pellet core and the film and the film coating surface) showed consistent results with dissolution tests. It seems that amylopectin subcoating can prevent the influx of the dissolution medium into the pellet core, and thus decrease the premature dissolution and release of the drug from the enteric-coated pellets in 0.1 N HCl solution. The drug release mechanism appeared to be osmotically driven release, and followed by diffusion through the polymer film.

Growth factor release from amylopectin hydrogel based on copper coordination.

This paper describes a biodegradable hydrogel matrix releasing basic fibroblast growth factor (bFGF) on the basis of protein metal coordination with the protein drug. The biodegradable hydrogel was prepared from amylopectin by its crosslinking with ethylene glycol diglycidyl ether, followed by introduction of diethylenetriaminepentaacetic acid (DTPA) residues for copper chelation. When bFGF was incorporated into the DTPA-introduced amylopectin hydrogel after chelation with Cu2+, an insignificant amount of bFGF was released from the hydrogel in buffered solution, in contrast to that without Cu2+ chelation. An increased ionic strength in the solution did not affect the bFGF release, indicating the occurrence of coordinate bonding of bFGF to the DTPA-introduced hydrogel through Cu2+ chelation. An implantation study with 125I-labeled amylopectin hydrogels demonstrated that they underwent degradation in the back subcutis of mice. Cu2+ chelation of hydrogels enabled bFGF to remain in the mouse back for a long time period, irrespective of DTPA introduction. However, DTPA residues were necessary to induce significant neovascularization by the Cu2+-chelating hydrogels incorporating bFGF. The DTPA-introduced amylopectin prevented Cu2+-induced deactivation of bFGF, again in marked contrast to DTPA-free amylopectin. It was concluded that biologically active bFGF could be incorporated to DTPA-introduced amylopectin through Cu2+ chelation in a stabilized state and was released as a result of hydrogel biodegradation, resulting in prolonged neovascularization.

Dietary amylose-amylopectin starch content affects glucose and lipid metabolism in adipocytes of normal and diabetic rats.

The aim of this study was to evaluate the effects of the chronic consumption of two starches, characterized by different glycemic indices and amylose-amylopectin content, on glucose metabolism in rat epididymal adipocytes. The two chosen starches were from mung bean (32% amylose) and cornstarch (0.5% amylose). The alpha-amylase digestibility was higher for the waxy cornstarch than that of the mung bean starch (60 +/- 4 vs. 45 +/- 3%, mean +/- SEM, respectively). The glycemic index of the waxy cornstarch diet (575 g starch /kg diet) was higher than that of the mung bean starch diet (107 +/- 7 vs. 67 +/- 5%, P < 0.01) when measured in vivo in two groups of normal rats (n = 9). In a subsequent study, normal and diabetic (streptozotocin-injected on d 2 of life) male Sprague-Dawley rats (18 per group) consumed a diet containing 575 g starch/kg diet as either waxy cornstarch or mung bean starch. After 3 wk, food intake, epididymal fat pad weights, and plasma glucose, insulin and triglyceride concentrations did not differ between diet groups. Adipocyte diameter was smaller in rats that consumed mung bean starch compared with those that consumed the waxy cornstarch diet (P < 0.01). The mung bean diet increased maximal insulin-stimulated 14C-glucose oxidation (% of basal values, P < 0. 05). In contrast, incorporation of 14C-glucose into total lipids was significantly lower in rats that consumed the mung bean diet (P < 0. 05). We conclude that in both normal and diabetic rats, the chronic replacement of a high glycemic index starch by a low glycemic index one in a mixed diet increases insulin-stimulated glucose oxidation, decreases glucose incorporation into total lipids and decreases epididymal adipocyte diameter. Thus, the type of starch mixed into the diet has important metabolic consequences at the cellular level in both normal and diabetic rats.