Effects of Dietary Corn Gluten Meal on Growth Performance and Protein Metabolism in Relation to IGF-I and TOR Gene Expression of Juvenile Cobia (Rachycentron canadum)

A growth experiment was conducted on cobia(Rachycentron canadum,initial weight 108.2 g ± 3.0 g) to investigate the effects of dietary corn gluten meal(CGM) levels on the fish growth,whole body composition and protein metabolism in relation to specific gene expression.Five isonitrogenous(crude protein 45%) and isoenergetic(gross energy 20 kJ g 1) practical diets were formulated by replacing 0%(the control),17.5%,35.0%,52.5%,and 70.0% of fish meal(FM) protein with CGM protein.No significant differences were observed in the survival,feed intake(FI),specific growth rate(SGR),feed efficiency(FE) and protein productive value(PPV) among fish fed diets with 0%,17.5%,35.0%,and 52.5% of CGM protein.However,these indices were significantly lower in fish fed the diet with 70.0% of CGM protein than those in fish fed the control diet(P < 0.05).The whole-body crude protein and lipid contents were significantly lower while the whole-body moisture content was significantly higher in fish fed the diet with 70.0% of CGM protein compared with the control group(P < 0.05).When 70.0% of FM protein was replaced by CGM,plasma total protein and cholesterol contents were significantly lower than those in the control group(P < 0.05).Fish fed the diet with 70.0% of CGM protein had significantly lower hepatic insulin-like growth factor I(IGF-I) expression levels than those in the control group(P < 0.05).However,no significant differences were observed in hepatic target of rapamycin(TOR),dorsal muscle IGF-I and TOR expression levels among dietary treatments.Results of the present study indicated that 52.5% of FM protein could be replaced by CGM in the diets without significant influences on the growth,feed utilization and protein metabolism of juvenile cobia.The present results might be useful for developing cost effective and sustainable cobia dietary formulations.

Soybean seed protein, oil, fatty acids, and mineral composition as influenced by soybean-corn rotation

Effects of crop rotation on soybean (Glycine max (L) Merr.) seed composition have not been well investigated. Therefore, the objective of this study was to investigate the effects of soybean-corn (Zea mays L.) rotations on seed protein, oil, and fatty acids composition on soybean. Soybeans were grown at Stoneville, MS, from 2005 to 2008 in five different scheduled cropping sequences. In 2007, following three years of rotation with corn, seed oleic acid percentage was significantly higher in any crop rotation than continuous soybean. The increase of oleic fatty acid ranged from 61 to 68% in 2007, and from 27 to 51% in 2008, depending on the rotation. The increase of oleic acid was accompanied by significant increases in seed concentrations of phosphorus (P), iron (Fe), and boron (B). In 2007, the increase of P ranged from 60 to 75%, Fe from 70 to 72%, and B from 34 to 69%. In 2008, the increase of P ranged from 82 to 106%, Fe from 32 to 84%, and B from 62 to 77%. Continuous soybean had higher linoleic:oleic ratio and linoleic: palmitic + stearic + oleic ratio, indicating that relative quantity of linoleic acid decreased in rotated crops. The total production of protein, oil, stearic and oleic fatty acids was the lowest in continuous soybean. The total production of palmitic acid was inconsistent across years. The results show that soybean- corn rotation affects seed composition by consistently increasing seed oleic fatty acid, P, Fe, and B concentrations. Higher oleic acid, unsaturated fatty acid, is desirable for oil stability and long-shelf storage. The mechanisms of how these nutrients are involved are not yet understood.

Effects of NaOH Treatment on Fiber, Crude Protein and Soluble Sugar Content of Corn Straw

[Objective] The paper was to study the effects of different levels of NaOH on fiber, crude protein and soluble sugar content of cornstraw. [Method] Four treatments were designed in the test, namely control group, group 1, group2 and group 3, which were added with 0, 2%, 3%and 4% NaOH according to the dry weight of corn straw, and the moisture of corn straw after treatment was 45%. After being treated at room tem-perature for 48 h, sensory evaluation and nutrient composition analysis were performed for each group, and the contents of neutral detergent fiber（NDF）, acid detergent fiber （ADF）, crude protein （CP） and soluble sugar （SS） were measured. [Result] With the increasing addition level of NaOH,the content of NDF and ADF decreased gradually, and significant differences were observed between group 3 （adding 4% NaOH） and control group（P〈0.05）. There was no significant difference in CP content among treatment groups（P〉0.05）; the SS content gradually increased, and there weresignificant differences between treatment groups and control group （P〈0.05）. [Conclusion] 4% NaOH reduced the fiber content and increased thesoluble sugar content of corn straw.

乳酸菌协同发酵玉米蛋白水解物工艺条件优化及其对抗氧化活性影响

该文以玉米蛋白水解物为原料,以鼠李糖乳杆菌YY⁃15和发酵乳杆菌YY⁃16为发酵菌株,通过单因素试验和响应面试验优化发酵条件,并对发酵后玉米蛋白水解物的体外抗氧化能力和氨基酸含量进行分析评价。结果表明,两株乳杆菌协同发酵玉米蛋白水解物的最佳发酵工艺为菌种体积比3∶1,玉米蛋白水解物浓度20.50%,接种量4%,果葡糖浆添加量5%,发酵温度39.5℃,发酵时间24 h。在该条件下,发酵后玉米蛋白水解物的体外DPPH自由基、羟自由基和超氧阴离子自由基三者清除能力的IC50值分别为0.227、0.200、12.851 mg/mL,Fe^(2+)螯合能力的IC_(50)为1.856 mg/mL,与发酵前相比分别提高了50.65%、34.64%、6.41%、41.36%。

玉米蛋白水解物对幽门螺旋杆菌感染诱导小鼠胃损伤的拮抗作用

目的:研究玉米蛋白水解物对幽门螺旋杆菌感染诱导小鼠胃损伤的保护作用。方法:以健康的昆明雄性小鼠为研究对象,适应性喂养7 d后,随机分为正常组、模型组、CPN200组(200 mg/kg m_(b))、CPN400组(400 mg/kg m_(b))、CPN600组(600 mg/kg m_(b))和阳性对照组,通过灌胃幽门螺旋杆菌建立感染小鼠胃部模型,连续灌胃玉米蛋白水解物5周后,测定小鼠胃组织中抗氧化能力、炎症因子和核转录因子相关指标水平和小鼠胃组织形态学变化。结果:与模型组相比,玉米蛋白水解物干预可以显著提高机体抗氧化水平,超氧化物歧化酶、谷胱甘肽过氧化物酶水平显著提高(P<0.05),丙二醛水平显著降低(P<0.05)。小鼠胃组织中促炎因子和趋化因子肿瘤坏死因子-α、白细胞介素-1β、髓过氧化物酶、单核细胞趋化蛋白1、角质细胞趋化因子水平均显著降低(P<0.05)。与模型组相比,小鼠胃组织中核转录因子信号通路Toll样受体4、髓样分化因子88以及核转录因子κB(nuclear factor-κB,NF-κB)等关键代谢物水平均显著降低(P<0.05)。结论:玉米蛋白水解物可以显著升高机体抗氧化水平,减轻脂质过氧化程度,降低胃组织炎症反应和抑制NF-κB信号通路反应,从而起到对幽门螺旋杆菌感染诱导小鼠胃损伤的拮抗效果。

改性玉米蛋白粉和肠膜蛋白粉组合替代鱼粉对凡纳滨对虾生长性能、饲料利用和免疫性能的影响

为研究饲料中改性玉米蛋白粉和肠膜蛋白粉组合替代鱼粉对凡纳滨对虾生长性能、饲料利用和免疫性能的影响。试验分别用复合蛋白源替代0、20%、40%、60%、80%和100%鱼粉,共制作了6组等氮等脂饲料,分别命名为CD1(基础料,对照组)、CD2、CD3、CD4、CD5组和CD6组,投喂对虾56 d。结果显示,与CD1组,复合蛋白源替代20%、40%、60%和80%鱼粉对凡纳滨对虾增重率(WG)和特定生长率(SGR)皆无显著影响(P>0.05)。CD6组对虾的WG、SGR、饲料效率(FE)、蛋白质效率(PER)和蛋白质沉积率(PPV)显著低于CD1组(P<0.05)。CD6组试验虾血清谷草转氨酶(AST)、谷丙转氨酶(ALT)和三酰甘油(TG)水平显著高于其他各组(P<0.05),而血清碱性磷酸酶(ALP)和总蛋白(TP)水平显著低于其他各组(P<0.05)。CD6组试验虾肝胰腺谷胱甘肽过氧化物酶(GPX)、超氧化物过氧化酶(SOD)和酸性磷酸酶(ACP)含量显著低于其它各试验组(P<0.05),同时丙二醛(MDA)含量显著升高(P<0.05)。以上结果表明,饲料中复合蛋白源能替代部分鱼粉而对凡纳滨对虾的生长性能没有显著影响,然而,复合蛋白源全替代鱼粉会降低凡纳滨对虾的生长性能、饲料利用率、免疫力和抗氧化能力。

pH循环法从玉米蛋白粉制备蛋白纳米颗粒的研究及其表征

采用pH循环法直接从玉米蛋白粉(CGM)制备蛋白纳米颗粒(CNPs),对其制备工艺进行了优化,对其性质进行了表征,并与利用玉米醇溶蛋白在相同条件下制备的纳米颗粒(ZNPs)进行了比较。结果表明,利用pH循环法可以成功从CGM中制备CNPs,且其最优条件为碱溶pH 13.0、碱溶温度60℃、碱提料液比1∶25、回调pH 7.0,在此条件下CNPs的得率相对于CGM中的蛋白质质量分数达到了69.20%。与ZNPs相比,CNPs具有相近的粒径(282.37 nm)且也携带负电荷,但是原子力显微镜观察结果表明其聚集程度更低;CNPs的疏水性氨基酸质量分数稍低(50.05%),但是α-螺旋和无规则卷曲的含量稍高。另外,CNPs的持水力和润湿性均显著优于ZNPs,且其接触角仅为45.5°,并表现出了更好的Pickering乳液稳定能力。因此,CGM可取代玉米醇溶蛋白作为pH循环法制备蛋白纳米颗粒的原料,这一过程工艺简单、成本较低,对于丰富CGM的综合利用途径、推动玉米蛋白纳米颗粒在食品工业中的应用具有重要意义。

复合蛋白源替代鱼粉对凡纳滨对虾生长性能、饲料利用和免疫性能的影响

试验旨在研究饲料中使用复合蛋白源(猪血球蛋白粉、玉米蛋白粉和酶解脱脂黑水虻粉)替代鱼粉对凡纳滨对虾生长性能、饲料利用、免疫性能和耐氨性的影响。挑选初重(1.01±0.01)g健康有活力的凡纳滨对虾1440尾,随机分为6组,每组4个重复,每个重复60尾凡纳滨对虾。复合蛋白源分别等氮、等脂替代0、20%、40%、60%、80%和100%的鱼粉,分别命名为M1组、M2组、M3组、M4组、M5组和M6组。试验期56 d。结果显示,M4组凡纳滨对虾的增重率和特定生长率显著高于M1组(P<0.05)。M2组、M3组和M4组凡纳滨对虾的饲料效率显著高于M1组(P<0.05)。M6组凡纳滨对虾血清中谷草转氨酶(AST)、谷丙转氨酶(ALT)活性和总胆固醇(CHO)、甘油三酯(TG)含量显著高于M1组(P<0.05),血清中碱性磷酸酶(AKP)活性和总蛋白(TP)含量显著低于M1组(P<0.05)。M6组凡纳滨对虾肝胰腺谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)和酸性磷酸酶(ACP)的活性显著低于其他各组(P<0.05),丙二醛(MDA)含量显著高于M1组、M2组和M3组(P<0.05)。氨氮胁迫18 h后,M6组凡纳滨对虾存活率显著低于其他各组(P<0.05)。研究表明,饲料中复合蛋白源替代鱼粉比例为60%时,可以改善凡纳滨对虾的生长性能,复合蛋白源替代鱼粉比例过高(超过80%)会降低凡纳滨对虾的饲料利用率、免疫力及抗应激能力。

基于参数优化VMD与XGBoost算法的玉米蛋白粉价格预测

玉米蛋白粉价格稳定对饲料工业可持续发展和国家粮食安全具有重要意义,但其价格序列具有非平稳、非线性特征,难以精确预测。试验旨在基于XGBoost算法,构建玉米蛋白粉价格预测模型。首先,利用鲸鱼算法(WOA)优化变模分解(VMD)的K值和惩罚参数,对原始价格序列进行自适应分解,降低数据噪声。其次,将Pearson特征筛选后的变量作为极限梯度提升树(XGBoost)模型的输入,进行训练和测试。最后,使用10折交叉验证和学习曲线检验模型性能,并结合SHAP模型分析关键影响因素的非线性效应。结果显示,上一期豆粕期货价格对本期玉米蛋白粉价格波动具有显著的正向影响。研究表明,贝叶斯算法(BO)优化的XGBoost模型具有较好的预测性能,优于基准模型。

蛋清蛋白絮凝处理脱除玉米秸秆水解液中的木质素衍生物

为了提升玉米秸秆水解液(corn stalks hydrolysate,CSH)的可生化降解性,研究了蛋清蛋白(egg white protein,EWP)絮凝处理对CSH中木质素衍生物去除的影响,并与氯化铁、阳离子聚丙烯酰胺等常规絮凝剂的效果进行对比。结果表明,在初始CODCr浓度为40 g/L的CSH中使用EWP进行热絮凝处理(100℃下加热5 min),CSH中大分子木质素(以浊度计算)去除率达(76.87±3.00)%,显著优于氯化铁、阳离子聚丙烯酰胺的处理结果 (P <0.05)。同时,EWP热絮凝处理未造成糖、呋喃及弱酸等化合物明显损失。这是由于EWP通过疏水反应与木质素衍生物结合,进一步通过巯基-二硫键交联形成大分子化合物,促进了木质素衍生物从CSH中去除。

S-烯虫酯水分散体的制备及其性能研究

S-烯虫酯是一种绿色、高效且对环境及非靶标生物安全的生物化学农药。然而,由于其在有氧、光照等条件下不稳定及不溶于水等问题,限制了其实际应用。本研究以玉米醇溶蛋白为载体,使用反溶剂法制备了负载S-烯虫酯的水分散体,实现了S-烯虫酯的高效负载。探讨了不同浓度的玉米醇溶蛋白和S-烯虫酯对纳米水分散体的微观形貌、载药量、包埋率、释放特性、贮藏稳定性及对烟草甲的防治功效的影响。

玉米蛋白粉的发酵及其在许氏平鲉饲料中的应用研究

玉米蛋白粉是玉米加工行业的副产物,是一种高能量和高蛋白的饲料原料。为了将玉米蛋白做成水产动物的饲料,对玉米蛋白粉进行了固态发酵研究并应用于海洋鱼类许氏平鲉的饲喂。研究表明,采用市售的菌酶协同饲料发酵剂,在料液比1∶0.7,发酵剂添加量0.7%,发酵温度35℃,物料初始pH值为6.5的条件下,恒温发酵72 h后,玉米蛋白粉中的粗蛋白含量提高至76%,相比于原始蛋白含量(58%)提高了29.6%,而且可溶性蛋白和多肽的比例增加,能够提高其在动物肠道中的消化率。结果表明,用发酵玉米蛋白饲喂海洋鱼类许氏平鲉,其替代鱼粉的最大占比达到25%,在此范围内对幼鱼的生长性能,如增重率、饲料系数和肥满度等,没有发生显著影响。研究为玉米蛋白粉在水产饲料中的可利用性及其高值化利用提供了新途径。

樱桃谷公鸭对玉米DDGS能量、蛋白质和氨基酸利用率的研究

【目的】研究樱桃谷公鸭对5个地区玉米DDGS的能量、蛋白质和氨基酸的利用率。【方法】将98只18周龄体重3.25 kg±0.25 kg的健康樱桃谷公鸭随机分为7组,每组14只,1只为1个重复,单只饲养于代谢笼。其中,5个试验组分别饲喂吉林、美国(粗)、美国(细)、山东和辽宁玉米DDGS与玉米淀粉按7∶3配制成的试验饲粮;玉米淀粉组饲喂100%玉米淀粉饲粮;内源组禁食。按强饲流程进行公鸭强饲试验和代谢试验,收集全部排泄物。测定强饲饲料及排泄物的总能、粗蛋白质和氨基酸等养分含量。【结果】辽宁玉米DDGS粗蛋白质含量显著低于其他4个试验组(P<0.05),美国(粗和细)玉米DDGS粗蛋白质含量显著低于吉林组(P<0.05)。美国(粗)玉米DDGS总能显著低于其他4个试验组(P<0.05)。美国(细)、辽宁组表观可利用蛋白质和真可利用蛋白质较美国(粗)、山东组均显著提高(P<0.05)。美国(粗)、辽宁组表观代谢能和真代谢能均显著高于吉林、山东组(P<0.05)。辽宁玉米DDGS苏氨酸、甘氨酸、组氨酸、精氨酸、支链氨基酸、苯丙氨酸和酪氨酸真可利用率均显著高于其他4个试验组(P<0.05),脯氨酸、天冬氨酸、丝氨酸、谷氨酸和丙氨酸5种非必需氨基酸真可利用率最高。【结论】5个不同地区玉米DDGS营养成分及能量、蛋白质和氨基酸利用率具有较大差异。樱桃谷公鸭的能量、蛋白质、氨基酸利用率排序为辽宁>美国(细)>美国(粗)>吉林>山东,5个不同地区玉米DDGS粗蛋白质含量排序为山东>吉林>美国(粗)>美国(细)>辽宁。

低酯果胶和玉米淀粉对泥鳅肌原纤维蛋白凝胶特性的影响

该研究旨在探讨外源添加物对肌原纤维蛋白凝胶特性的影响,以改善淡水鱼糜的性能。将泥鳅肌原纤维蛋白与不同含量(0%~25%)的低酯果胶和玉米淀粉混合制备复合胶,采用质构仪、色差分析仪、扫描电子显微镜和红外光谱仪对其性能进行研究。结果表明,加入低酯果胶后,凝胶硬度、强度和持水力显著升高,蒸煮损失显著降低;添加玉米淀粉后,凝胶强度和持水力显著提高。同时,低酯果胶添加量和玉米淀粉添加量分别为25%和10%时,凝胶网络结构最紧凑有序。红外结果显示,添加低酯果胶和玉米淀粉能促进热凝胶过程中β-折叠结构的形成。该研究结果可为泥鳅鱼糜的加工提供理论指导。

响应面法优化复合益生菌固态发酵玉米-豆粕型日粮工艺

研究旨在对复合益生菌发酵玉米-豆粕型日粮产生酸溶蛋白的工艺进行优化,为复合益生菌发酵饲料的应用提供参考。在单因素试验的基础上以酸溶蛋白含量为响应值,以接种量、料水比、发酵时间、发酵温度为自变量,通过Box-Behnken设计试验,优化复合益生菌发酵玉米-豆粕型日粮的发酵工艺。结果表明:乳酸杆菌RSG-1∶枯草芽孢杆菌B-1∶地衣芽孢杆菌Y5-39为1∶1∶4时,酸溶蛋白含量最高为5.30%;响应面优化后复合益生菌最佳发酵工艺为:含水量48%,接种量10%,发酵温度48℃,发酵时间10 d,酸溶蛋白含量为13.31%,在考虑生产实际的情况下,将发酵温度调整为37℃。综上,研究确定了多菌种组合固态发酵玉米-豆粕型日粮的最佳工艺条件:含水量为48%、接种量(乳酸杆菌∶枯草芽孢杆菌∶地衣芽孢杆菌=1∶1∶4)10%、发酵温度37℃、发酵时间10 d,酸溶蛋白含量达到13.06%。

Process Parameter Study on Microwave-assisted Foam-mat Drying Properties of Corn Soaking Water

In order to study the microwave-assisted foam-mat drying properties of corn soaking water and optimize process parameters, a quadratic regression orthogonal rotary method was used to analyze the influence of microwave power, material weight, material thickness and drying time on moisture content（dry basis）, color value and protein content. Results showed that the primary and secondary sequence of parameters with regard to moisture content（d. b.） was drying time, microwave power, material weight and material thickness; the primary and secondary sequence of parameters with regard to color value was material weight, drying time, microwave power and material thickness; the primary and secondary sequence of parameters with regard to protein content was drying time, material weight, microwave power and material thickness. Optimum conditions were obtained as microwave power of 560 W, material weight of 46.88 g, material thickness of 6.20 mm and drying time of 8.01 min. The results might provide the theoretical basis and technical support for the microwave-assisted foam-mat drying of corn soaking water to produce yeast protein power.

Verification of protein sparing by feeding carbohydrate to common carp Cyprinus carpio

A 9-week feeding trial in floating freshwater cages(1.0 m×1.0 m×2.0 m) was conducted to study the effects of different dietary levels of protein and starch on growth,body composition,and gene expression of enzymes in common carp,Cyprinus carpio(mean body weight,36.12±1.18 g) to evaluate the protein-sparing effect of dietary carbohydrate.Four diets were formulated with corn starch as the carbohydrate source to obtain corn starch levels of 6.5%,13%,19.5%,or 26%and protein levels of 30.5%,28.2%,26.4%,and 24.2%.The results showed no differences in growth performance of fish fed the diets with different protein and corn starch levels,but body composition and glucose metabolic enzyme activity of carp were significantly affected by the different diets(P<0.05).Weight gain,specific growth rate,and the feed conversion ratio were not different in fish fed the different dietary treatments.Protein efficiency ratio increased significantly as corn starch level increased(P<0.05).Whole-body crude lipid composition increased with increasing dietary corn starch level(P<0.05).Glucokinase(GK),hexokinase,and pyruvate kinase(PK) activities increased significantly with increasing dietary corn starch level(P<0.05),whereas glucose-6-phosphate(G6Pase) activity decreased with increasing dietary corn starch level(P<0.05).GK gene expression was significantly higher in fish fed the high-corn starch diet than those fed the low-corn starch diet(P<0.05).G6 pase gene expression tended to decrease with increasing starch level(P>0.05).In summary,the results indicate a protein-sparing effect by substituting carbohydrate in the diet of common carp.

STUDY ON THE DISTRIBUTION OF SELENIUM AND OTHER ELEMENTS IN CORN SAMPLES BY NAA AND BIOCHEMICAL TECHNIQUE

Biochemical technique was used to separate three kinds of proteins (albumin, globulin and gliadin) in corn samples froin high selenium areas and normal areas in Erxi autonomous region of Hubei Province, China. The contents of Se and other elements in these proteins were determined by neutron activation analysis (NAA). The results show that Se is enriched in corn proteins at high selenium area, while Cu, Al, Mn, V and Cl are also enriched in varying degrees.

Analysis on Plant and Quality Traits in an Improved Population of Corn

An improved population NEAU 2 was tested in Triple Test Cross design to analyze the genetic structure of 31 plants and quality traits. The results suggested that additive effect played an important role in all of these traits except for filling property trait V1. Nine traits such as grain yield and volume weight were determined mainly by the additive effect. Globulin and starch content were controlled by significant dominant effect. The leaf number above ear and most quality traits studied were controlled by both additive and dominance effect, and 4 traits such as 100 kernel weight were determined by both additive and epistasis effect. However, the heredity of plant height, ear position, and so on was determined by all these kinds of genetic effects. In quality improvement, direct selection could increase the content but not improve the quality of corn protein. Direct selection for albumin content and the ratio of glutelin to zein was effective and might be a better way to improve the protein quality of corn. Starch content might be raised by direct selection, but it might increase the content of amylopectin meanwhile. It was better to increase gross fat content by direct and indirect selection through the weight ratio of embryo to endosperm, which might also be effective to increase gross fat.