基于胆固醇外排、摄取与合成的柑橘果胶寡糖调控胆固醇代谢机制

为揭示柑橘果胶寡糖H1（POS_H1）对胆固醇代谢的调控机制,采用巨噬细胞模型,基于胆固醇代谢外排、摄取与合成机制对POS_H1调控胆固醇代谢进行了研究。结果显示：POS_H1和POS_H1的肠道菌群发酵产物（P24）均通过显著上调肝X受体α-ATP结合盒转运体ABCA1/ABCG1通路中关键基因的蛋白表达量来促进巨噬细胞胆固醇外排。POS_H1对巨噬细胞胆固醇摄取相关基因的蛋白表达无显著影响,但P24却可以通过显著抑制A类清道夫受体和分化抗原簇36的蛋白表达来抑制巨噬细胞对胆固醇的摄取。POS_H1和P24均可通过显著抑制胆固醇合成基因3-羟基-3甲基-戊二酰辅酶A还原酶蛋白的表达来抑制巨噬细胞胆固醇的合成。研究结果表明,POS_H1通过促进胆固醇排出、抑制胆固醇摄取与合成调控胆固醇代谢,这是POS_H1调控胆固醇代谢的机制之一,且该机制与肠道菌群发酵POS_H1有关。     

外源寡糖对山羊瘤胃液酶活及粗饲料瘤胃降解率的影响

为比较不同外源寡糖对山羊瘤胃液主要酶活及常用粗饲料瘤胃降解率的影响,选用体况良好、体重(62.80±2.45)kg、装有永久性瘤胃瘘管的成年崂山奶山羊去势公羊6只。采用6×4不完全拉丁方试验设计。羊只分别饲喂基础饲粮(对照)及添加1%外源寡糖[甘露寡糖(MOS)、半乳甘露寡糖(GMOS)、寡木糖(XOS)、低聚异麦芽寡糖(IMO)、果寡糖(FOS)]的试验饲粮;试验进行4期,每期35 d,其中预试期25 d,正试期10 d。结果表明:1)饲粮添加MOS可显著提高羧甲基纤维素酶活性(P<0.05);GMOS、IMO和FOS可显著提高滤纸纤维素酶活性(P<0.05);添加IMO、XOS、GMOS和FOS可显著或极显著提高β-葡萄糖苷酶活性(P<0.05或P<0.01);添加MOS、GMOS、XOS、FOS和IMO可显著或极显著提高木聚糖酶活性(P<0.05或P<0.01);添加IMO、GMOS和FOS可显著提高中性蛋白酶活性(P<0.05);添加FOS可显著提高α-淀粉酶活性(P<0.05)。2)饲粮添加MOS、GMOS、IMO、XOS、FOS可提高玉米全株青贮、花生蔓、羊草、苜蓿中干物质、中性洗涤纤维、酸性洗涤纤维的瘤胃降解率。综合各项指标,在1%添加水平下,GMOS和FOS在山羊饲粮中添加效果较好。     

甘露寡糖对生长绵羊瘤胃发酵功能(体外)的影响

采用批次培养的方法,研究了体外条件下日粮添加甘露寡糖对生长绵羊瘤胃发酵功能的影响。甘露寡糖的添加水平为0,0.20%,0.40%,0.60%,0.80%以及1.00%。结果表明,日粮添加甘露寡糖可以提高培养液中的挥发性脂肪酸(VFA)含量;可以提高培养液中的菌体蛋白(BCP)含量,并以0.60%的添加量效果最佳;添加量在0.80%以上时,可以显著降低(P<0.05)培养液中的NH3-N含量;对培养残渣中的中性洗涤纤维(NDF)含量没有显著影响(P>0.05)。研究初步证明,日粮添加甘露寡糖可以在一定程度上提高生长绵羊的瘤胃发酵功能。     

Effect of Adding Different Mannan Oligosaccharide to Diets with Different Concentrate to Forage Ratios on Rumen Degradability of Fiber in Sheep

To investigate the effect of adding mannan oligosaccharide to diets with different concentrate to forage ratios on the degradability of neutral detergent fiber (NDF) and acid detergent fiber(ADF) in rumen of sheep by nylon bags technique,6 wethers (White Suffolk♂×Small-tailed Han sheep♀) installed permanent rumen fistula were used for offering rumen fluid.The 4×6 two-factor experimental design was chosen and the two factors were the ratio of concentrate to forage (A1(20:80),A2(30:70),A3(40:60),A4(50:50)) and the dose of mannan oligosaccharide (B1 (0),B2 (0.4%),B3 (0.8%),B4 (1.2%),B5 (1.6%),B6 (2.0%)).The results showed that the rumen degradability of NDF and ADF in different times,degradation parameters and effective degradability were influenced by the factor A significantly (P< 0.05).The rumen degradability of NDF and ADF in each time of group A1 were higher than group A3 and A4 (P< 0.05).Expect for 24 h,the rumen degradability of ADF were influenced significantly by the factor B,and the rumen degradability of ADF in group B5 was higher than group B1 and B2 (P< 0.05).The rumen effective degradability of NDF in group A3 was significantly higher than groups A1 and A2 (P< 0.05), and a little higher than group A4 (P >0.05),which showed that the rumen effective degradability of NDF and ADF were higher when the ratio of concentrate to forage was 40:60.     

几种寡糖类物质对菜心产量和品质的影响

采用叶片喷施和根部处理2种方式,研究了不同寡糖类物质及其用量对菜心产量和品质的影响.结果表明,叶片喷施不同寡糖均能一定程度促进菜心增产,改善其品质,其中20 mg/L壳寡糖和40 mg/L海藻酸钠寡糖效果最好,产量、可溶性糖、可溶性蛋白、Vc含量均显著增加,游离氨基酸无显著变化.根部处理海藻酸钠及其寡糖能提高菜心产量,改善其品质,二者最适浓度均为20 mg/L;寡聚半乳糖醛酸和壳寡糖对菜心增产作用不大,在高浓度时还有明显抑制作用,品质也有一定程度的下降.     

Metabolic process of the C-sugars on the translocation pathways of cucumber plants

Studies on the metabolic process of photoassimilates and enhancement of sugar accumulation into fruit are important in fruit crop production. The metabolic process of the ¹⁴C-photoassimilates in cucumber plants was analyzed with respect to the vascular system. At 4 h after the start of ¹⁴CO₂ feeding, the ¹⁴C-photoassimilates synthesized in a selected leaf on the main shoot were translocated to the vascular bundles of the internode just below the ¹⁴CO₂-fed leaf. The radioactivity of ¹⁴C-stachyose was as high as that of ¹⁴C-sucrose in the vascular bundles of petiole and internode just below the ¹⁴CO₂-fed leaf as well as in the midrib, while the radioactivity of ¹⁴C-stachyose was lower than that of ¹⁴C-sucrose in the mesophyll. The ¹⁴C-photoassimilates appeared to have been translocated without any metabolic change in the translocation pathways between the petiole and internode just below the ¹⁴CO₂-fed leaf, because the ratio of ¹⁴C-stachyose radioactivity in the two parts was similar. At 8 h after the start of ¹⁴CO₂ feeding, the ¹⁴C-photoassimilates were translocated to the fruit. In the vascular bundles of the peduncle, the ratios of the radioactivity of ¹⁴C-stachyose and ¹⁴C-raffinose were lower, and the ratio of the radioactivity of ¹⁴C-sucrose was higher, than that at the petiole and internode just below the ¹⁴CO₂-fed leaf at 8 h after the start of ¹⁴CO₂ feeding. Therefore, it seemed that ¹⁴C-stachyose and ¹⁴C-raffinose were hydrolyzed to ¹⁴C-sucrose in the peduncle.     

Antinutritional factors of chickpea and pigeonpea and their removal by processing

Protease inhibitors, amylase inhibitors, phytolectins, polyphenols, and oligosaccarides are important antinutritional factors of chickpea and pigeonpea. Research on these factors is reviewed and compared to those in other grain legumes. Both chickpea and pigeonpea are consumed in various forms as processed food. The effects of such processing practices as cooking, germination, and fermentation to reduce the levels of these antinutritional factors are also discussed.     

Evaluation of a novel animal milk oligosaccharide biosimilar: macronutrient digestibility and gastrointestinal tolerance,fecal metabolites,and fecal microbiota of healthy adult dogs and in vitro genotoxicity assays

Milk oligosaccharides (MO) are bioactive compounds in mammalian milk that provide health benefits to neonates beyond essential nutrients. GNU100, a novel animal MO biosimilar, was recently tested in vitro, with results showing beneficial shifts in microbiota and increased short-chain fatty acid (SCFA) production, but other effects of GNU100 were unknown. Three studies were conducted to evaluate the safety, palatability, and gastrointestinal (GI) tolerance of GNU100. In study 1, the mutagenic potential of GNU100 was tested using a bacterial reverse mutation assay and a mammalian cell micronucleus test. In study 2, palatability was assessed by comparing diets containing 0% vs. 1% GNU100 in 20 adult dogs. In study 3, 32 adult dogs were used in a completely randomized design to assess the safety and GI tolerance of GNU100 and explore utility. Following a 2-wk baseline, dogs were assigned to one of four treatments and fed for 26 wk: 0%, 0.5%, 1%, and 1.5% GNU100. On weeks 2, 4, and 26, fresh fecal samples were collected to measure stool quality, immunoglobulin A, and calprotectin, and blood samples were collected to measure serum chemistry, inflammatory markers, and hematology. On weeks 2 and 4, fresh fecal samples were collected to measure metabolites and microbiota. On week 4, total feces were collected to assess apparent total tract macronutrient digestibility. Although revertant numbers were greater compared with the solvent control in tester strain WP2uvrA(pKM101) in the presence of metabolic activation (S9) in the initial experiment, they remained below the threshold for a positive mutagenic response in follow-up confirmatory tests, supporting that GNU100 is not mutagenic. Similarly, no cytotoxicity or chromosome damage was observed in the cell micronucleus test. The palatability test showed that 1% GNU100 was strongly preferred (P < 0.05; 3.6:1 consumption ratio) over the control. In study 3, all dogs were healthy and had no signs of GI intolerance or illness. All diets were well accepted, and food intake, fecal characteristics, metabolite concentrations, and macronutrient digestibilities were not altered. GNU100 modulated fecal microbiota, increasing evenness and Catenibacterium, Megamonas, and Prevotella (SCFA producers) and reducing Collinsella. Overall, the results suggest that GNU100 is palatable and well-tolerated, causes no genotoxicity or adverse effects on health, and beneficially shifts the fecal microbiota, supporting the safety of GNU100 for the inclusion in canine diets.     

Chemical characterization of milk oligosaccharides of the island flying fox (Pteropus hypomelanus) (Chiroptera: Pteropodidae)

Although a considerable amount of information has accumulated about oligosaccharides in the milk and colostrum of representatives of various mammalian orders, nothing is so far known concerning these sugars in the milk of any bat species (order Chiroptera). In this study, we determined that the following oligosaccharides occur in milk of the island flying fox, Pteropus hypomelanus (Chiroptera: Pteropidae): Gal(α1–3)Gal(β1–4)Glc (isoglobotriose), Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc (lacto‐N‐neotetraose), Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc (lacto‐N‐neohexaose) and Neu5Gc(α2–3)Gal(β1–4)Glc (3′‐NGc‐SL). However, lactose was found to be the dominant saccharide in this milk, as in most eutherian mammals. The biologic importance of oligosaccharides in Chiropteran milks warrants further study.     

绿色饲料添加剂的研究进展及其应用现状

畜产品中有害物质残留是影响畜产品安全的主要问题。饲料添加剂是引起有害物质残留超标的主要因素之一,研究和开发安全、绿色饲料添加剂,替代抗生素添加剂,发展绿色畜牧业已成为现代畜牧业的发展方向。对中草药添加剂、益生素和复合酶作为绿色新型饲料添加剂的特点、功能、研究应用现状及存在的问题和发展应用前景加以综述,以期为业界人士在研究、开发、应用绿色饲料添加荆产品过程中提供参考。