低血糖生成指数液态奶的开发及测试

为获得营养均衡的调制牛奶,满足人体的多种营养需求,添加多种维生素和矿物质,设计出一款适用于糖尿病人、亚健康人群、体重管理、皮肤管理等人群饮用的低血糖生成指数（Glycemic Index,GI）的牛奶。稳定性试验结果表明,静置12 天后,牛奶无显著脂肪上浮,体系稳定性良好;人体GI值试验结果表明,调制牛奶的餐后血糖值上升和下降均较葡萄糖餐后血糖值平稳,有较好稳定餐后血糖的效果,表明开发的调制牛奶为低GI食品（GI值=22.86）。人体饱腹感试验结果显示,和普通纯牛奶对比,调制牛奶具有显著提高饱腹感的效果。     

Impact of native form oat β-glucan on starch digestion and postprandial glycemia

Whole grain oats, as a rich source of β-glucan, have been shown beneficial to glycemic control. In the current study, the impact of native form β-glucan in oat grains (NFO-glucan) on starch digestion and postprandial glycemia was investigated. The dry-milling prepared NFO-glucan sample was enriched with native form β-glucan (15.6%), and an in vitro starch digestion assay of NFO-glucan (0.5% starch equivalent) showed a significant decrease of starch digestion rate compared to oat starch (0.5%, w/v). However, pretreatment by either β-glucanase or pepsin significantly increased the starch digestion. Consistently, an in vivo examination on the postprandial glycemia of the cooked NFO-glucan sample using a mouse model displayed a significant decrease of postprandial glycemia compared to gelatinized oat starch. Further experiment on the pasting property of NFO-glucan sample by a rapid visco-analyser demonstrated both β-glucan and protein affected its viscosity profiles. Scanning Electronic Microscope (SEM) observation revealed a network-like native structure of β-glucan that might encapsulate protein and starch to reduce the enzyme accessibility and so the digestion of starch. Novel food processing technologies to maintain the native form of β-glucan in oat grains might be a better way to modulate the postprandial glycemia of oat-based whole grain foods.     

Insoluble fibres,satiety and food intake in cats fed kibble diets

Fibre is generally considered to dilute food energy, alter intestinal transit time and promote satiety; however, in cats, conflicting results have been found. In this study, two insoluble fibres were evaluated in four feline diets: control (no added fibre); diet with 10% sugar cane fibre; diet with 20% sugar cane fibre; and diet with 10% cellulose. The experiment was conducted with 32 cats, eight animals per diet, over 42 days: 1–7 for diet adaptation; 8–14 for total collection of faeces for digestibility; 15–17 for fresh faeces collection for fermentation products measurements; 18–20 for gastrointestinal transit time determination; 21 and 37 to evaluate the pattern of food intake; and 22 and 42 to assess satiety. Means were compared by analysis of variance and orthogonal contrasts, and the pattern of food intake was compared by repeated‐measures analysis of variance (p < 0.05). The cats exhibited increased food intake after fibre addition to the diets (p < 0.05), achieving similar energy consumption. Cellulose and the two levels of sugar cane fibre reduced nutrient availability and energy digestibility, but only sugar cane fibre reduced fat digestibility (p < 0.05). Faecal output and the number of defecations per day increased with fibre inclusion (p < 0.05). Gastrointestinal transit time did not change with sugar cane fibre inclusion, but it was reduced with cellulose addition (p = 0.032). The pattern of food intake did not change, but cats fed fibre‐supplemented diets exhibited greater consumption of a challenge meal, increasing energy intake (p < 0.01) when exposed to a palatable, energy‐dense food.     

胆囊收缩素对动物消化和摄食的调节

胆囊收缩素是一种广泛分布在动物消化系统、中枢及外周神经系统的脑肠肽,对动物胃肠道的作用主要是直接抑制胃酸分泌,抑制进食后的胃排空,并通过外周和中枢神经系统抑制胃运动。同时作为一种内源性生理饱感信号,抑制摄食行为,本文就此进行了阐述。     

Blue Whiting (Micromesistius poutassou) Protein Hydrolysates Increase GLP-1 Secretion and Proglucagon Production in STC-1 Cells Whilst Maintaining Caco-2/HT29-MTX Co-Culture Integrity

Inducing the feeling of fullness via the regulation of satiety hormones presents an effective method for reducing excess energy intake and, in turn, preventing the development of obesity. In this study, the ability of blue whiting soluble protein hydrolysates (BWSPHs) and simulated gastrointestinal digested (SGID) BWSPHs, to modulate the secretion and/or production of satiety hormones, such as glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK) and peptide YY (PYY), was assessed in murine enteroendocrine STC-1 cells. All BWSPHs (BW-SPH-A to BW-SPH-F) (1.0% w/v dw) increased active GLP-1 secretion and proglucagon production in STC-1 cells compared to the basal control (Krebs–Ringer buffer) (p < 0.05). The signaling pathway activated for GLP-1 secretion was also assessed. A significant increase in intracellular calcium levels was observed after incubation with all BWSPHs (p < 0.05) compared with the control, although none of the BWSPHs altered intracellular cyclic adenosine monophosphate (cAMP) concentrations. The secretagogue effect of the leading hydrolysate was diminished after SGID. Neither pre- nor post-SGID hydrolysates affected epithelial barrier integrity or stimulated interleukin (IL)-6 secretion in differentiated Caco-2/HT-29MTX co-cultured cells. These results suggest a role for BWSPH-derived peptides in satiety activity; however, these peptides may need to be protected by some means to avoid loss of activity during gastrointestinal transit.     

Sourdough fermentation of wholemeal wheat bread increases solubility of arabinoxylan and protein and decreases postprandial glucose and insulin responses

Glycemic responses to most of the conventional breads are high, including breads made of wholemeal flour. Baking technology is known to affect these responses. The aim of the present study was to investigate effects of xylanase enzyme treatment and sourdough fermentation in wholemeal wheat bread baking on postprandial glucose and insulin responses and on in vitro protein digestibility. The wheat breads were made of 100% flour from peeled kernels by a straight dough or sourdough fermentation method, and with or without using xylanase during mixing of dough. Standard white wheat bread was used as a reference. All test bread portions contained 50 g available carbohydrate and were served in random order to eleven insulin resistant subjects. Blood samples for measuring glucose and insulin concentrations were drawn over 4 h. The sourdough wholemeal wheat bread resulted in the lowest postprandial glucose and insulin responses among the four tested breads (treatment × time; p = 0.000 and p = 0.022, respectively). There were differences in solubility and depolymerisation of protein and arabinoxylan among the breads but these did not fully explain the in vivo findings. In conclusion, the health effects of wholemeal wheat bread can be further improved by using sourdough process in breadmaking.     

Effect of feeding a high‐carbohydrate or a high‐fat diet on subsequent food intake and blood concentration of satiety‐related hormones in dogs

Although studies in rodents and humans have evidenced a weaker effect of fat in comparison to carbohydrates on the suppression of food intake, very few studies have been carried out in this field in dogs. This study investigates the effects of a high‐carbohydrate (HC ) and a high‐fat (HF ) diets on subsequent food intake and blood satiety‐related hormones in dogs. Diets differed mainly in their starch (442 vs. 271 g/kg dry matter) and fat (99.3 vs. 214 g/kg dry matter) contents. Twelve Beagle dogs received the experimental diets at maintenance energy requirements in two experimental periods, following a cross‐over arrangement. In week 7 of each period, blood concentrations of active ghrelin, glucagon‐like peptide (GLP ‐1), peptide YY , insulin, and glucose were determined before and at 30, 60, 120, 180, and 360 min post‐feeding. The following week, intake of a challenge food offered 180 min after the HC and HF diets was recorded over two days. In comparison to the dogs on the HC diet, those on the HF diet had a higher basal concentration of GLP ‐1 (p  = .010) and a higher total area under the curve over 180 min post‐prandial (tAUC _0–180) (p  = .031). Dogs on the HC diet showed a higher elevation of ghrelin at 180 min (p  = .033) and of insulin at 360 min (p  = .041), although ghrelin and insulin tAUC _0–180 did not differ between the two diets (p  ? .10). Diet had no effect on challenge food intake (p  ? .10), which correlated with the tAUC _0–180 of ghrelin (r = .514, p  = .010), insulin (r = ?.595, p  = .002), and glucose (r = ?.516, p  = .010). Feeding a diet high in carbohydrate or fat at these inclusion levels does not affect the feeding response at 180 min post‐prandial, suggesting a similar short‐term satiating capacity.     

Feeding Grass Hay Before Concentrate Mitigates the Effect of Grain-Based Concentrates on Postprandial Plasma Interleukin-1β

When fed to horses, high-starch diets elevate plasma concentrations of interleukin-1β (IL-1β) as soon as 1 hour posteating. This increase in IL-β is possibly because of changes in intestinal pH that result from rapid bacterial fermentation of starches and sugars in the digestive tract. The purpose of this research was to investigate the effect of feeding 0.9 kg of grass hay 30 minutes before feeding a concentrate meal on the postprandial rise in IL-1β, compared with control horses receiving the same concentrate without hay first. Six mature geldings were used in a switchback design. Horses were fasted overnight before being offered a concentrate feed that provided 1.2 g/kg bodyweight of nonstructural carbohydrates. Plasma was harvested 30 minutes before hay feeding and 1, 2, 4, 6, and 8 hours postfeeding. Concentrations of IL-1β and d-lactate were analyzed by repeated measures analysis of variance. The hay-first treatment reduced (P = .034) postprandial concentrations of IL-1β at all time points compared with the control horses. An interaction between hour and treatment was detected for mean d-lactate concentrations (P = .037), with lower concentrations in hay-first fed horses at postfeeding hours 1, 2, and 4, compared with control horses. Given these findings, we believe that feeding a small amount of hay before feeding a meal of moderate starch and sugar content reduced the negative effects of rapid starch and sugar fermentation in the equine digestive tract, evidenced by reduced postprandial d-lactate and IL-1β concentrations.     

Relationships between dietary ascorbic acid status and deficiency,weight gain and brain neurotransmitter levels in juvenile rainbow trout,Salmo gairdneri

A study was conducted to determine the interrelationships between dietary ascorbic acid (AA) concentrations, brain neurotransmitter levels and weight gain in juvenile rainbow trout. At the end of 4 weeks and until the end of 12 weeks of feeding test diets of varying AA concentrations (0–320 mg AA/kg diet), increased weight gain was noted in fish fed the AA-free diet. However, by the end of 13 weeks and until the end of the experiment this phenomenon was no longer evident; instead the fish showed the more classical deficiency signs of anorexia and decreased weight gain. After 12 and 24 weeks, there were no significant differences in brain serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), norepinephrine (NE) or dopamine (DA) between fish reared on the different test diets. However, after 12 weeks of feeding the test diets, brain 5-HT, brain AA and weight gain were significantly correlated with one another. No such relationships were found for brain NE or brain DA. After 24 weeks of feeding the diets, the relationships between brain 5-HT, brain AA and weight gain were no longer apparent. Similarly, after 24 weeks brain NE and DA were also unrelated to brain AA and weight gain. These results provide evidence that in very young rainbow trout, AA deficiency, brain 5-HT levels and weight gain were related. However in fish reared on the diets for 24 weeks these relationships were no longer evident.