Standardized ileal digestibility of amino acids in soybean meal fed to non-pregnant and pregnant sows

Background Two studies were designed to determine standard ileal crude protein(CP)and amino acid(AA)digestibility of soybean meal(SBM)from different origins fed to non-pregnant and pregnant sows.Seven solvent-extracted SBMs from soybeans produced in the USA,Brazil,and China were selected.In Exp.1,eight different diets were created:a nitrogen(N)-free diet and 7 experimental diets containing SBM from different origins as the only N source.Eight non-pregnant,multiparous sows were arranged in an 8×8 Latin square design(8 periods and 8 diets).In Exp.2,the diet formula was the same as in Exp.1.Eight gestating sows(parity 3)were assigned to 4 different diets in a replicated 4×3 Youden square design(three periods and four diets)in mid-gestation and again in late-gestation stages.Results When fed to non-pregnant and late-gestating sows,the standardized ileal digestibility(SID)of CP and most AAs from different SBM were not significantly different(P>0.05).When fed to mid-gestating sows,the SID values for Arg,His,Lys,Phe,Cys,Gly,Ser,and Tyr in SBM 1 were lower than in SBM 4 and 5(P<0.05),whereas SID for Leu from SBM 5 was higher than in SBM 1 and 4(P<0.05).SID values for Ile,Ala,and Asp from SBM 4 were lower than in SBM 1 and 5(P<0.05).Sows had significantly greater SID values for Lys,Ala,and Asp during mid-gestation when compared with late-gestation stages(P<0.05).Mid-gestating sows had greater SID value for Val and lower SID value for Tyr when compared with non-pregnant and late-gestating sows(P<0.01),whereas non-pregnant sows had significantly greater SID value for Met when compared with gestating sows(P<0.01).Conclusions When fed to mid-gestating sows,the SID values for most AAs varied among SBM samples.The SID values for Lys,Met,Val,Ala,Asp,and Tyr in SBM were affected by sow gestation stages.Our findings provide a cornerstone for accurate SBM use in sow diets.

Effect of the Dietary Substitution of Fish Meal with Achatina fulica Meat Meal on the Growth Performance and Production Cost of African Catfish (Clarias gariepinus) Fingerlings

Fishmeal is the most preferred source of protein in aquafeeds, but it is expensive and scarce. Hence, Achatina fulica meat meal (AFM), which is much less preferred for human consumption out of three species of African giant land snails, was tested as a fishmeal substitute for Clarias gariepinus growth. Five iso-nitrogenous and iso-calorific diets were formulated, in which AFM substituted fish meal at 0% (control or Diet A), 25% (Diet B), 50% (Diet C), 75% (Diet D) and 100% (Diet E). These dietary treatments were each replicated thrice in a completely randomized design experiment, using 36-L plastic tanks in which the fish were fed daily rations corresponding to 5% of their body weight, for 8 weeks. Water quality parameters in the tanks were monitored. Proximate analyses were conducted on the fish meal, snail meal and experimental diets before the feeding trials. Cost-benefit analysis of the different diets was performed. The crude protein content of AFM (69.18%) was significantly higher than that of fish meal (55.81%). There was no significant difference (P > 0.05) in the mean weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio and survival rate in fish fed Diet A and Diet B. The best protein efficiency ratio (0.77) was recorded in fish fed Diet B. Furthermore, the survival rate of fish increased with increased levels of AFM substitution. Water quality parameters were within a suitable range for tropical fish culture, indicating that the AFM did not pollute the water. The fish fed 25% AFM diet significantly (P Clarias gariepinus diets at a 25% substitution level. The aquaculture industry can thus exploit the availability of this feed resource.

Debaryomyces hansenii supplementation in low fish meal diets promotes growth,modulates microbiota and enhances intestinal condition in juvenile marine fish

Background The development of a sustainable business model with social acceptance,makes necessary to develop new strategies to guarantee the growth,health,and well-being of farmed animals.Debaryomyces hansenii is a yeast species that can be used as a probiotic in aquaculture due to its capacity to i)promote cell proliferation and differen-tiation,ii)have immunostimulatory effects,iii)modulate gut microbiota,and/or iv)enhance the digestive function.To provide inside into the effects of D.hansenii on juveniles of gilthead seabream(Sparus aurata)condition,we inte-grated the evaluation of the main key performance indicators coupled with the integrative analysis of the intestine condition,through histological and microbiota state,and its transcriptomic profiling.Results After 70 days of a nutritional trial in which a diet with low levels of fishmeal(7%)was supplemented with 1.1%of D.hansenii(17.2×10^(5) CFU),an increase of ca.12%in somatic growth was observed together with an improve-ment in feed conversion in fish fed a yeast-supplemented diet.In terms of intestinal condition,this probiotic modu-lated gut microbiota without affecting the intestine cell organization,whereas an increase in the staining intensity of mucins rich in carboxylated and weakly sulphated glycoconjugates coupled with changes in the affinity for certain lectins were noted in goblet cells.Changes in microbiota were characterized by the reduction in abundance of several groups of Proteobacteria,especially those characterized as opportunistic groups.The microarrays-based transcrip-tomic analysis found 232 differential expressed genes in the anterior-mid intestine of S.aurata,that were mostly related to metabolic,antioxidant,immune,and symbiotic processes.Conclusions Dietary administration of D.hansenii enhanced somatic growth and improved feed efficiency param-eters,results that were coupled to an improvement of intestinal condition as histochemical and transcriptomic tools indicated.This probiotic yeast stimulated host-microbiota interactions without altering the intestinal cell organization nor generating dysbiosis,which demonstrated its safety as a feed additive.At the transcriptomic level,D.hansenii pro-moted metabolic pathways,mainly protein-related,sphingolipid,and thymidylate pathways,in addition to enhance antioxidant-related intestinal mechanisms,and to regulate sentinel immune processes,potentiating the defensive capacity meanwhile maintaining the homeostatic status of the intestine.

Comparative effects of soy protein concentrate,enzyme‑treated soybean meal,and fermented soybean meal replacing animal protein supplements in feeds on growth performance and intestinal health of nursery pigs

Background Soy protein supplements,with high crude protein and less antinutritional factors,are produced from soybean meal by different processes.This study evaluated the comparative effects of various soy protein supplements replacing animal protein supplements in feeds on the intestinal immune status,intestinal oxidative stress,mucosaassociated microbiota,and growth performance of nursery pigs.Methods Sixty nursery pigs(6.6±0.5 kg BW)were allotted to five treatments in a randomized complete block design with initial BW and sex as blocks.Pigs were fed for 39 d in 3 phases(P1,P2,and P3).Treatments were:Control(CON),basal diet with fish meal 4%,2%,and 1%,poultry meal 10%,8%,and 4%,and blood plasma 4%,2%,and 1%for P1,P2,and P3,respectively;basal diet with soy protein concentrate(SPC),enzyme-treated soybean meal(ESB),fermented soybean meal with Lactobacillus(FSBL),and fermented soybean meal with Bacillus(FSBB),replacing 1/3,2/3,and 3/3 of animal protein supplements for P1,P2,and P3,respectively.Data were analyzed using the MIXED procedure in SAS 9.4.Results The SPC did not affect the BW,ADG,and G:F,whereas it tended to reduce(P=0.094)the ADFI and tended to increase(P=0.091)crypt cell proliferation.The ESM did not affect BW,ADG,ADFI,and G:F,whereas tended to decrease(P=0.098)protein carbonyl in jejunal mucosa.The FSBL decreased(P<0.05)BW and ADG,increased(P<0.05)TNF-α,and Klebsiella and tended to increase MDA(P=0.065)and IgG(P=0.089)in jejunal mucosa.The FSBB tended to increase(P=0.073)TNF-α,increased(P<0.05)Clostridium and decreased(P<0.05)Achromobacter and alpha diversity of microbiota in jejunal mucosa.Conclusions Soy protein concentrate,enzyme-treated soybean meal,and fermented soybean meal with Bacillus could reduce the use of animal protein supplements up to 33%until 7 kg body weight,up to 67%from 7 to 11 kg body weight,and entirely from 11 kg body weight without affecting the intestinal health and the growth performance of nursery pigs.Fermented soybean meal with Lactobacillus,however,increased the immune reaction and oxidative stress in the intestine consequently reducing the growth performance.

Sanitary Quality of the Meals Served in the Canteens and Vicinity of the Lagoon Mother and Child University Hospital Centre and National Hospital and University Centre Hubert Koutoukou Maga of Cotonou (Benin)

Background: Food safety is an integral part of food security. It refers to the protection of the food supply against risks of microbial, chemical and physical origin at every stage of the food chain. The study aimed to investigate the sanitary quality of meals served in the canteens and vicinity of the Lagoon Mother and Child University Hospital Centre (CHU-MEL) and National Hospital and University Centre Hubert Koutoukou Maga (CNHU-HKM) of Cotonou. Methods: It was a cross-sectional with a data collection period from 16 March to 22 April 2021. There were 32 vendors surveyed and 40 meals sampled for microbiological examination. We collected data on the vendors’ socio-demographic characteristics, working environment, health status, knowledge and food hygiene practices. Results: About 83% of the meals contained pathogenic microorganisms. All meals had a temperature from 4°C to 60°C called the “danger zone”. The level of knowledge about food hygiene was low in 65.7% of the vendors. About 47% had poor personal and clothing hygiene, food storage and service practices. Conclusion: These results show that the meals sold in the CHU-MEL and CNHU-HKM could present a health risk for the consumer. There is a need for improvement of the sanitary quality of the meals delivered in the canteens and vicinity of these hospitals.

Evaluation of Nutritional Value and Safety of Black Soldier Flies Fed on Dead Pig Meat and Bone Meal

[Objectives]This study was conducted to evaluate the nutritional value and safety of black soldier flies fed with dead pig meat and bone meal(DPMBM)and to explore the resource utilization of DPMBM.[Methods]The general nutrient composition,amino acids,fatty acids and mineral elements of black soldier fly meal(BSLM)were detected and analyzed.[Results]The results showed that the contents of moisture,crude protein,crude fat and ash in BSLM were 3.42%,42.31%,34.04%and 5.40%,respectively.The contents of total amino acids(TAA),essential amino acids(∑EAA)and non-essential amino acids(∑NEAA)and umami amino acids(∑DAA),the EAA/TAA value and the EAA/NEAA value were 37.93%,13.08%,24.85%,13.43%,34.47%,52.61%,respectively.A total of eight kinds of saturated fatty acids and seven kinds of unsaturated fatty acids were detected,accounting for 63.65%and 32.67%of the total fatty acids.Among the major mineral elements,the content of Ca was the highest,followed by K,Mg and Na.Among the trace mineral elements,the content of Mn was the highest,followed by Fe,Zn,Cu,Ni,Cr,Cd,As,Pb,Se,Sn,Ti,Sb and Hg.The contents of heavy metal mineral elements in BSLM were far lower than the limits specified in Hygienical Standard for Feeds.[Conclusions]In conclusion,BSLM has high nutritional value and good safety of heavy metals,and thus great potential for development and utilization as a high quality dietary protein,fat and mineral elements source.

花生粕的饲用资源开发及在养殖业的应用

花生粕粗蛋白含量和代谢能均高于大豆饼粕,但缺乏赖氨酸、蛋氨酸等,且赖氨酸与精氨酸比例失衡,蛋白质品质欠佳。花生粕极易感黄曲霉毒素,同时在高温压榨条件下,蛋白质变性严重,导致蛋白质和氨基酸的利用率降低。由于花生粕自身品质缺陷和加工质量的不稳定性,限制了其在配合饲料中的应用。利用微生物发酵或菌酶协同发酵技术,可使花生粕中含有丰富的益生菌、寡肽、有机酸等,改善其适口性,有效降解霉菌毒素或抗营养因子,有利于改善动物肠道健康,增强机体免疫,提高生产性能,缓解蛋白质原料匮乏的现状。文章综述了花生粕资源状况、营养特性、生物发酵花生粕研究现状及在养殖业中的应用,为花生粕安全高效可持续利用提供参考依据。

魔芋果蔬健康代餐粉的功能特性

研究了不同杀菌条件对自制代餐粉功能特性及产品品质的影响,紫外冷杀菌可以最大限度地保留代餐粉原来的功能特性,但是杀菌效率不高;而射频杀菌既可以保留功能性成分又可以取得良好的杀菌效果。将自制代餐粉与市售代餐粉进行对比,结果表明自制代餐粉总酚质量分数及抗氧化活性均高于市售代餐粉,且自制代餐粉的风味滋味均优于市售代餐粉。为研究自制代餐粉的贮藏稳定性,对自制代餐粉进行了3个月的贮藏实验。结果表明,自制代餐粉在90 d的贮藏期内功能特性、微生物指标均在标准范围内。为了延长代餐粉的保质期,应尽可能将代餐粉置于干燥、阴凉处贮藏。

脱酚棉籽蛋白替代豆粕对凡纳滨对虾生长、饲料利用和免疫应答的影响

为研究脱酚棉籽蛋白替代凡纳滨对虾(Litopenaeus vannamei)饲料中豆粕的效果,以初始体质量为(0.81±0.01) g的凡纳滨对虾为研究对象,进行6周的养殖实验。对照组饲料中豆粕含量为25%(编号为S0),分别用4.93%、10.06%、14.80%、19.73%的脱酚棉籽蛋白等蛋白替代25%、50%、75%、100%的豆粕(分别编号为S25, S50, S75, S100)。每个处理3个重复,每个重复70尾对虾。实验表明,与对照组相比,脱酚棉籽蛋白替代100%豆粕对对虾的生长和饲料利用无显著影响,但显著降低了胰蛋白酶和淀粉酶活性,显著降低了干物质和粗蛋白表观消化率。与对照组相比,脱酚棉籽蛋白替代75%豆粕时,对虾肠道中免疫相关基因的表达显著升高。肠道组织形态学观察实验表明,脱酚棉籽蛋白替代100%豆粕会影响对虾的肠道健康,肠道绒毛高度显著降低。结果表明,脱酚棉籽蛋白替代饲料中100%的豆粕不会对凡纳滨对虾的生长和饲料利用产生显著影响,但会影响对虾的消化、免疫应答以及肠道健康。

低温/中温花生粕蛋白的理化特性及结构特性分析

对低温/中温花生粕的感官色差、功能特性和结构特性进行了研究和分析,旨在为提高花生粕的综合利用价值提供理论基础。结果表明,低温花生粕呈象牙色,中温花生粕呈灰白色。从功能特性上来看,低温/中温花生粕蛋白的持油性、乳化性和泡沫稳定性无显著性差异。低温花生粕蛋白具有更好的溶解度、起泡性、持水性、热稳定性,中温花生粕蛋白具有更好的乳化稳定性。进一步通过分子量、二级结构、DSC对蛋白质结构进行分析,低温花生粕和中温花生粕蛋白质二级结构主要是β-折叠、β-转角,中温花生粕蛋白变性程度更高,低温花生粕的蛋白结构相对更松散。低温花生粕蛋白具有更高的变性温度和热焓值,且具有更好的热稳定性。

北京市60岁及以上老年人三餐就餐情况分析

目的:了解北京市60岁及以上老年人三餐就餐情况及影响因素。方法:利用2015年中国成人慢性病与营养监测中北京市60岁及以上老年人的数据,分析三餐就餐情况及其影响因素。结果:北京市60岁及以上老年人的每日三餐的比例为77.5%,每日早餐为86.5%,每日午餐为88.1%,每日晚餐为92.4%。60岁及以上老年人早餐、午餐及晚餐最主要食物均来自家庭制作的比例分别为82.1%、81.8%、85.7%。多因素Logistic回归模型分析结果显示,家庭月收入越高、腰围不适宜者、每日身体活动时间≥30 min/d及不饮酒的老年人每日三餐的比例高(均P<0.05);年龄越高早餐来自家庭制作的比例高(P<0.05);家庭月收入越高、高密度脂蛋白不正常者及不饮酒的老年人午餐来自家庭制作的比例高(均P<0.05);不饮酒的老年人晚餐来自家庭制作的比例高(P<0.05)。结论:北京市60岁及以上老年人每日三餐的比例和三餐食物来自家庭制作的比例均较低,急需相关部门开展有针对性的干预,让更多的老年人每日三餐都有保障。

火麻籽粕代餐饼干配方及抗氧化活性研究

火麻籽粕是火麻籽提取油脂加工后的副产物,其蛋白质含量为50%左右,油脂含量为5%左右,与火麻籽相比具有高蛋白、低油脂的特性。同时,压榨提取油脂的过程使火麻籽粕具有独特香气,可作为代餐饼干的添加成分。选取不同油厂生产的压榨火麻籽粕1、压榨火麻籽粕2制备代餐饼干,通过单因素实验和正交实验,参考感官评分,确定在100 g低筋面粉中加入6 g压榨火麻籽粕1、20 g黄油、13 g木糖醇、0.2 g碳酸氢钠或8 g压榨火麻籽粕2、25 g黄油、13 g木糖醇、0.2 g碳酸氢钠时,饼干口感、形态最佳。添加了压榨火麻籽粕1、压榨火麻籽粕2的饼干体外消化率均高于80%,与添加了相同比例的大豆粕饼干的体外消化率无显著差异,同时体外消化产物具有1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力。

花生粕发酵工艺条件优化及其提取物体外抗氧化活性研究

试验以花生粕为原料,利用乳酸菌、芽孢杆菌和酵母复合发酵技术进行固态发酵,探究不同含水量、接种量、发酵时间对发酵花生粕体外抗氧化活性的影响。利用3因素3水平的响应面试验设计对花生粕发酵条件进行优化,以发酵花生粕水溶性提取物对1,1-二苯基-2-三硝基苯肼(DPPH)清除率为评价指标,确定最适发酵条件。同时考察提取物对2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)二铵盐自由基(ABTS^(+)·)、羟自由基(·OH)、DPPH自由基清除率和铁还原能力的影响,来评估其体外抗氧化活性。响应面优化结果为含水量52%、接种量5%、发酵时间85 h,在此条件下发酵的花生粕,其水溶性提取物对DPPH的清除率可达到60.58%,比未发酵花生粕的52.96%提高了14.39%(P<0.05)。体外抗氧化活性研究结果显示:当提取物质量浓度大于0.2 mg/mL时,发酵组对ABTS^(+)·、·OH清除能力以及铁还原能力显著高于对照组(P<0.05),当提取物质量浓度大于0.8 mg/mL时,发酵组对DPPH自由基清除能力显著高于对照组(P<0.05),但均显著低于L-抗坏血酸(VC)组(P<0.05)。研究表明,发酵显著提高了花生粕的抗氧化活性,可为花生粕功能性物质的研发和高值化利用提供参考。

发酵牡丹籽粕对黄山黑鸡生产性能、蛋品质、蛋黄中脂肪酸含量及血清生化指标的影响

本试验旨在研究发酵牡丹籽粕对黄山黑鸡生产性能、蛋品质、蛋黄中脂肪酸含量及血清生化指标的影响。选取240日龄产蛋率及体重相近的黄山黑鸡864只,随机分为3组,每组4个重复,每个重复72只。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加5%(5%FPSM组)和9%发酵牡丹籽粕(9%FPSM组)的试验饲粮。预试期1周,正试期8周。结果表明:1)与对照组相比,5%FPSM组的产蛋率显著升高(P<0.05),料蛋比和平均日采食量显著降低(P<0.05);9%FPSM组的产蛋率和平均日采食量极显著降低(P<0.01)。2)与对照组相比,9%FPSM组的蛋形指数显著升高(P<0.05),蛋壳颜色显著降低(P<0.05)。3)与对照组相比,5%FPSM组的蛋黄中ω-3多不饱和脂肪酸(PUFA)含量显著升高(P<0.05);9%FPSM组的蛋黄中总饱和脂肪酸(SFA)含量和ω-6/ω-3 PUFA显著或极显著降低(P<0.05或P<0.01),总PUFA和ω-3 PUFA含量显著或极显著升高(P<0.05或P<0.01)。4)与对照组相比,5%FPSM组的血清甘油三酯(TG)、免疫球蛋白A(IgA)、免疫球蛋白G(IgG)含量和碱性磷酸酶(ALP)活性及总抗氧化力(T-AOC)极显著升高(P<0.01),血清超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性和免疫球蛋白M(IgM)含量极显著降低(P<0.01);9%FPSM组的血清低密度脂蛋白(LDL)、TG、尿素氮(UN)、IgA、IgM含量和ALP活性及T-AOC显著或极显著升高(P<0.05或P<0.01),血清高密度脂蛋白(HDL)和丙二醛(DMA)含量极显著降低(P<0.01)。由此可见,饲粮中添加5%的发酵牡丹籽粕可提高黄山黑鸡的生产性能;添加5%和9%的发酵牡丹籽粕可提高黄山黑鸡的蛋黄中ω-3 PUFA含量,提高机体抗氧化能力和免疫力。本试验条件下,黄山黑鸡饲粮中发酵牡丹籽粕的适宜添加比例为5%。

超声辅助酶法提取玉米胚芽粕水解蛋白及其抗氧化活性

以玉米胚芽粕为原料,研究超声波辅助碱性蛋白酶提取玉米胚芽粕水解蛋白的工艺条件。通过单因素试验初步确定超声波辅助酶法提取玉米胚芽粕水解蛋白的条件,在单因素试验基础上进行正交试验设计,并测定其抗氧化活性。结果表明,最优提取条件为超声温度50℃、超声时间50 min、超声功率140 W,在此条件下,玉米胚芽粕的水解蛋白提取率为90.6%。对DPPH自由基和羟自由基的IC_(50)分别为17.56µg/mL和28.41µg/mL。

液态饲喂杂粕型饲粮对生长猪生长性能、养分消化率、血清炎性因子及粪便短链脂肪酸含量的影响

本试验旨在研究液态饲喂杂粕型饲粮对生长猪生长性能、养分消化率、血清炎性因子及粪便短链脂肪酸(SCFAs)含量的影响。选取平均体重为(30.00±4.26)kg的“杜×长×大”三元杂交猪126头,随机分为3组,每组7个重复,每个重复6头猪。试验Ⅰ组饲喂豆粕型颗粒饲粮;试验Ⅱ组饲喂杂粕型颗粒饲粮(由双低菜籽粕、玉米胚芽粕、喷浆玉米皮及米糠替代部分豆粕和玉米组成);试验Ⅲ组饲喂杂粕型液态饲粮,即在杂粕型饲粮的基础上加入2.7倍的水,混合均匀后饲喂。各组饲粮营养水平基本一致。试验期56 d。结果表明:1)试验全期,与试验Ⅰ组相比,试验Ⅱ组平均日采食量和平均日增重分别降低了2.29%和5.33%(P>0.05),料重比提高了3.40%(P>0.05);与试验Ⅱ组相比,试验Ⅲ组平均日采食量和平均日增重分别提高了7.04%(P<0.05)和6.32%(P>0.05)。2)试验Ⅱ组和试验Ⅲ组干物质、总能和粗蛋白质消化率极显著低于试验Ⅰ组(P<0.01),粗脂肪、磷和粗灰分消化率显著低于试验Ⅰ组(P<0.05)。试验Ⅱ组和试验Ⅲ组间各养分消化率均无显著差异(P>0.05)。3)试验Ⅲ组粪便丁酸含量显著高于试验Ⅱ组(P<0.05),与试验Ⅰ组差异不显著(P>0.05)。4)与试验Ⅰ组相比,试验Ⅱ组和试验Ⅲ组血清抗炎因子白细胞介素-10(IL-10)含量极显著提高(P<0.01),试验Ⅱ组血清促炎因子白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)含量显著提高(P<0.05);与试验Ⅱ组相比,试验Ⅲ组血清IL-1β含量显著降低(P<0.05),血清白细胞介素-6(IL-6)、白细胞介素-2(IL-2)和TNF-α含量有一定程度降低但未达到显著水平(P>0.05)。综上可知,与豆粕型颗粒饲粮相比,杂粕型颗粒饲粮会降低生长猪采食量和养分消化率,提高血清炎性因子含量,而通过液态方式饲喂杂粕型饲粮可改善饲粮适口性,提高生长猪采食量,降低血清促炎因子IL-1β含量,对养分消化率无改善作用。

玉米蛋白粉替代豆粕对肉牛生长性能、氮代谢及屠宰性能的影响

文章旨在研究玉米蛋白粉(Corn Gluten Meal,CGM)替代豆粕对肉牛生长性能、氮代谢及屠宰性能的影响。试验将96头健康、370 kg左右的西门塔尔肉牛随机分为4组,每组3个重复,每个重复8头。CON组根据肉牛饲养标准(NY/T 815-2004)配制全混合日粮,其余3组在全混合日粮中分别添加2.5%(CGML组)、5.0%(CGMM组)、7.5%(CGMH组)的玉米蛋白粉(等氮替代豆粕),试验为期80 d。结果表明:(1)与CON组相比,CGMH组肉牛的末重、平均日增重显著降低(P<0.05),料重比显著提高(P<0.05)。4组中CGML组肉牛的末重、平均日增重最高,料重比最低。(2)与CON组相比,CGMM组、CGMH组肉牛的沉积氮、氮利用率显著降低(P<0.05),CGML组肉牛的沉积氮、氮利用率高于CON组,但无显著差异(P>0.05)。(3)与CON组相比,CGMH组肉牛的宰前活重、胴体重、净肉重均显著降低(P<0.05)。4组中CGML组肉牛的宰前活重、胴体重、净肉重最高。结论:综合各项指标,在不考虑饲料成本的情况下,肉牛全混合日粮中玉米蛋白粉的适宜添加水平为2.5%。

外卖智能派单的订单-骑手多目标匹配模型及其适应性算法研究

随着外卖业的快速发展,外卖智能派单成为外卖服务的重要形式。然而,目前相关研究侧重于研究外卖配送路径问题,不利于解决外卖智能派单的多目标动态决策中存在的问题。本文从外卖订单-骑手匹配的角度,分析了外卖平台智能派单的五个基本目标和四个基本约束,构建了多目标的订单-骑手匹配优化模型,进而给出了基于适应性策略的实时优化算法。最后,本文设计了外卖智能派单的仿真实验,对比了骑手-订单数量均衡、骑手供过于求、骑手供不应求等三种情况下的优化情况,验证了基于适应性策略的实时优化算法的优化效果。本研究对外卖平台发展智能派单模式具有较好的理论与实践价值。

响应面法优化藜麦代餐粉工艺

以催芽藜麦粉、木糖醇、黑芝麻粉、脱脂奶粉为原料,以上述原料所占质量百分比及感官评价为指标进行单因素对照试验。在单因素试验的基础上,选取催芽藜麦粉用量为6.40 g,木糖醇用量为6.99 g,脱脂奶粉用量为10.36 g,羧甲基纤维素钠用量0.80 g,黑芝麻粉用量4.00 g作为优化因素进行响应面法分析,结果表明,各因素对结果的影响排序为催芽藜麦粉>木糖醇>脱脂奶粉。

枯草芽孢杆菌发酵蟹壳粉产蛋白酶的研究

本试验由蟹壳粉和蔗糖组成蟹壳粉培养基,通过测定发酵液中的蛋白酶活来确定最佳的培养基组成成分,利用单因素试验和响应面优化的方法优化蟹壳粉培养基,使枯草芽孢杆菌发酵蟹壳粉来产蛋白酶,提高废弃蟹壳的回收率,减少对环境的污染。试验结果表明:当蟹壳粉的浓度为5.12%,枯草芽孢杆菌的接种量为3.02%,蔗糖浓度为11.00%,初始pH为7.07时,枯草芽孢杆菌发酵蟹壳粉产酶的酶活最大值为17.4220 U/mL,较单因素试验时的最高蛋白酶酶活力14.2290 U/mL有一定的提升。