鸡毛降解菌的分离鉴定

为了筛选降解鸡毛生产蛋白饲料的菌种,试验采用富集分离筛选法,从绍兴富盛山里养鸡场堆砌废羽毛土样中筛选鸡毛降解菌。采用测定发酵液可溶性蛋白和氨基酸含量的方法对分离菌进行复筛,并通过形态学、生理生化反应和16S rDNA测序,对降解能力最强的菌株进行鉴定。结果表明:从养鸡场堆砌废羽毛土样中分离得到11株鸡毛降解菌,CTC385-G8降解能力最强,鉴定为嗜麦芽寡养单胞菌,说明CTC385-G8是良好的鸡毛降解菌。     

羽毛降解菌的筛选及其降解特性研究

本试验旨在从实验室保藏菌株中筛选出可用于羽毛降解的菌株并优化其培养条件,应用于羽毛的生物降解。以酪蛋白培养基进行菌株初筛,以羽毛为唯一有机营养源制作的羽毛培养基进行菌株复筛;通过细菌形态学观察和16S rDNA序列测定进行菌株鉴定,并对所筛菌株在羽毛培养基中的培养条件进行优化研究。结果表明：1)通过酪蛋白培养基筛选出8株能产生降解圈且透明度高的菌株。2)通过单根羽毛培养基和羽毛降解液指标测定联合方法筛选出1株可3 d降解羽毛、产可溶性蛋白的菌株NLG1。3)经鉴定并命名为贝莱斯芽孢杆菌NLG1(Bacillus velezensis NLG1)。4)菌株NLG1培养优化条件为羽毛底物浓度2.5%(m/v),初始pH 10,接种活菌数109CFU/mL,温度27℃,外加碳源为可溶性淀粉,发酵时间3 d。5)优化条件下降解羽毛,测得发酵液中可溶性蛋白含量为(32.76±0.07)μg/mL,水解氨基酸总量由27.41 mg/g提升到112.18 mg/g,测得游离氨基酸及衍生物的种类由25种增加至31种(增加的氨基酸为胱氨酸、苯丙氨酸、天冬酰胺、α-氨基丁酸、β-氨基异丁酸、β-丙氨酸),...     

米曲霉和枯草芽孢杆菌对羽毛粉降解效果研究

为提高羽毛粉的营养价值,通过测定蛋白酶活力和羽毛粉中可溶性蛋白含量,对米曲霉和枯草芽孢杆菌对羽毛粉的降解效果进行研究。结果表明:发酵72 h后,米曲霉产蛋白酶活力达到3 256.61 U/g(P<0.05),枯草芽孢杆菌产蛋白酶活力达到690.03 U/g(P<0.05)。米曲霉发酵羽毛粉48 h,可溶性蛋白含量由最初的2.21 mg/g提高到362.07 mg/g(P<0.05)。结果显示,米曲霉和枯草芽孢杆菌均可对羽毛粉起到降解作用,其中米曲霉的降解效果更为明显。     

羽毛粉的五种加工方法

目前,我国主要采用以下五种方法进行羽毛粉的加工生产. 一 高温高压水解法 水解羽毛粉主要依靠水解过程中时间、压力、温度的控制.其加工过程为:收集羽毛,除尘清洗后,装入水解罐中,在高温高压条件下水解,然后烘干、粉碎、化验、包装成成品.这种加工工艺较为先进,其突出特点是彻底破坏羽毛角蛋白质稳定的空间结构,从而使它变成畜禽可消化吸收的可溶性蛋白,消化率达90%以上,但由于水解后二硫键断裂,会使胱氨酸的含量减少.     

酶制剂处理羽毛粉的研究

为探索酶制剂处理羽毛粉提高其可溶性蛋白含量的效果，在实验室中，采用体外酶解法，对羽毛粉进行了七个酶水平的酶解处理。通过对酶解前后羽毛粉中可溶性蛋白含量和游离氨基酸含量的变化酶化效果的分析，得出０．１２０％的酶水平效果较佳。     

水解羽毛粉喂鹅试验

禽类羽毛由硬蛋白类中的角蛋白组成,含水极少,粗蛋白含量高达75～85%,但未经有效处理,其利用率极低。水解羽毛粉是经过高压水解后,加工成为易被消化吸收的氨基酸或短肽等水分子物质,利用率可提高到80.3%。然而,羽毛粉中蛋氨酸、赖氨酸和色氨酸的含量较少,在鸡上的研究表明,由于羽毛粉的氨基酸不平衡而影响其蛋白质的利用     

羽毛蛋白饲料添加剂的制备工艺研究

实验以鸡羽毛为原料采用化学水解法制备动物饲料添加剂可溶性羽毛蛋白水解物,通过L93(4)正交实验设计以羽毛溶解率为考察指标,确定羽毛蛋白饲料添加剂的最佳制备工艺条件:Ca(OH)2为羽毛质量的13%、固液比1:9、反应温度126℃和反应时间180min。羽毛蛋白水解物的粗蛋白质含量84.70%、胃蛋白酶消化率为90.60%和粗灰分含量11.01%。     

水解羽毛粉替代豆粕饲喂生长猪的效果研究

选用20kg左右的DLY生长猪64头,随机分为4个处理,每个处理4个重复,每个重复4头,分别饲喂基础日粮、添加2%、4%、6%水解羽毛粉（等蛋白替代豆粕）的日粮。结果表明,随着试验日粮中水解羽毛粉添加量的提高,试验猪的日采食量和日增重降低,而料肉比上升,并且6%处理组差异达到显著（P〈0.05）;各处理组的干物质表观消化率、蛋白质表观消化率和有机物表观消化率均差异不显著（P〉0.05）,而氮的表观生物学价值和净蛋白利用率随着水解羽毛粉添加量的提高明显降低,并且6%处理组的净蛋白利用率显著低于对照组（P〈0.05）和2%处理组（P〈0.05）;2%处理组的单位增重饲料成本较对照组降低0.20元/kg。     

水解膨化羽毛粉

水解膨化羽毛粉是通过物理法，即蒸气压力445千帕，温度121℃，蒸煮30分钟，然后将温度升至150℃熟化，瞬间膨化而成。水解膨化羽毛粉质地疏松，消化率明显提高。其蛋白质含量76%以上，是优质蛋白质原料。在鸡鸭日粮中添加3%的水解膨化羽毛粉可取代2%鱼粉，有利于羽毛生长，缩短换羽毛粉可取代2%鱼粉，有利于羽毛生长，缩短换羽期和防止鸡的啄癖。     

动物蛋白水解酶制备羽毛多肽的工艺优化

通过正交试验并结合中试试验,利用动物蛋白水解酶,研究不同工艺条件下制备的羽毛多肽粉对肽含量、粗蛋白含量和胃蛋白酶消化率等指标的影响,通过对结果进行极差和方差分析,获得制备羽毛多肽粉的最优条件参数。试验表明,制备羽毛多肽粉的最优条件为:底物浓度8%、pH8.5、酶添加量1.5%酶解时间12h,在此条件下获得羽毛多肽粉肽含量66.89%,粗蛋白含量84.99%,胃蛋白酶消化率达到92.95%。     

角蛋白降解菌分离、鉴定及其降解机制研究

实验旨在筛选具有高效角蛋白水解活性的微生物,并对其降解羽毛角蛋白机制进行研究,为提高角蛋白生物降解率提供理论指导。采用透明圈和完整羽毛降解相结合的方法,从废弃羽毛中筛选角蛋白降解菌,并进一步研究其羽毛角蛋白降解过程。获得一株可高效降解角蛋白菌株,基于形态观察和16S rDNA分子鉴定,该菌被命名为Bacillus licheniformis CP-7,其5 d可将天然完整羽毛完全降解。CP-7发酵过程产生大量巯基、可溶性蛋白和亚硫酸盐。分离发酵48 h菌株胞内、胞外粗酶液,发现胞外酶液具有较高的角蛋白酶活性,而胞内酶液具有一定二硫键还原酶活性。胞内酶液能够极显著地促进胞外酶液水解角蛋白活性(P<0.01),但对酪蛋白水解活性无影响(P>0.05)。筛选菌CP-7为具有高二硫键还原能力的角蛋白降解菌,二硫键还原酶可能是高效降解羽毛角蛋白的关键。     

地衣芽孢杆菌CP-16脂类水解酶的研究

本试验旨在通过异源表达获得地衣芽孢杆菌(Bacillus licheniformis)CP-16的脂类水解酶,并探究其在羽毛降解过程中的作用。试验以地衣芽孢杆菌CP-16基因组DNA为模板,扩增脂类水解酶基因,转化入大肠杆菌中表达,获得重组酶L-4。研究重组酶L-4的适宜p H、p H稳定性、适宜温度、温度稳定性以及有机溶剂和金属离子对其相对活性的影响,同时探究其对角蛋白酶K水解天然羽毛角蛋白的作用。结果显示,获得的脂类水解酶基因大小为747 bp,编码248个氨基酸,在大肠杆菌中成功表达出重组酶L-4,其分子质量约为28.3 ku,酯酶活性为0.42 U/m L,适宜p H为6.5,适宜温度为50℃;在p H 6.5~9.5条件下处理30 min相对活性保持80%以上,在低于50℃温度条件下处理30 min相对活性保持70%以上。二价铁离子(Fe~(2+))、钠离子(Na~+)、锰离子(Mn~(2+))、钙离子(Ca~(2+))对重组酶L-4相对活性具有激发作用,钡离子(Ba~(2+))、锌离子(Zn~(2+))、铜离子(Cu~(2+))、镍离子(Ni~(2+))对重组酶L-4相对活性具有抑制作用。当有机溶剂浓度为30%时,重组酶L-4在二甲基亚砜(DMSO)和甲醇中保存97%和85%的相对活性,在丙酮、乙醇中保存45%以上的相对活性,在异丙醇中保存不到20%的相对活性,而在乙腈中相对活性基本完全丧失。用重组酶L-4预处理天然羽毛底物,可提高角蛋白酶K对底物的水解效率,促进率为4.32%。由此可见,脂类水解酶可降解羽毛表层脂质,可在促进角蛋白酶水解羽毛角蛋白中发挥作用。     

Multiple feather follicle cysts in a Moroseta hen (Gallus gallus)

An 8-month-old white feathered, black skinned Moroseta hen was presented for examination because of numerous 2 mm- to 30 mm-diameter irregularly shaped, hard nodules in the skin of the head, wings, back, and abdomen. The nodules were confined to the skin and did not involve subcutaneous tissues. Nodules consisted of dilated feather follicles packed with a caseous tan-to-pale-yellow material admixed with feather remnants. Histologically, affected feather follicles were markedly dilated and filled with laminated keratin debris. Necrosis of the epidermis and perifollicular lymphocyte infiltration was also present. Bacteriologic investigation of internal organs was negative, while secondary bacteria, Proteus spp. and Bacillus spp., were isolated from skin nodules. A concomitant lice infestation of Menopon spp., as well as leg mange caused by Cnemidocoptes spp., were also present. These bacterial isolates and parasites were not related to the disease condition. The condition observed was differentiated from benign feather follicle tumors, and a diagnosis of multiple feather follicle cysts was made. In addition, a breed predisposition was hypothesized.     

Loosening of the feather follicle attachment by subcutaneous application of crude papain

1. The application of crude papain to cause loosening of feathers in chickens after death was successful in a laboratory experiment.

2. The treatment disrupted keratin cross‐bridges between the feather shaft and the follicle, and may have proteolysed feather follicle muscles.     

Properties of alkaline‐hydrolyzed waterfowl feather keratin

The properties of hydrolyzed feather keratin (HFK) were compared to those of hydrolyzed wool keratin (HWK) with the aim of developing better ways to utilize feather keratin waste. Amino acid analysis showed that HFK contained more hydrophobic amino acids did than HWK. Although gel permeation chromatography indicated that HFK and HWK had more low‐molecular weight peptides than their intact sources, Fourier transform infrared spectroscopy indicated that both hydrolyzed keratins retained their original secondary structure. The physical properties of HFK were evaluated by treating HFK to human hair fibers. HFK treatment enhanced significantly the surface hydrophobicity and strength of fibers, and HFK was more permeable into hair fibers. These results suggest that HFK is suitable for industrial applications to improve fibers. In addition, HFK may be suitable for raw material of products requiring both flexibility and hydrophobicity, such as films and biodegradable plastics.     

羽毛角蛋白降解的研究进展

羽毛角蛋白是一种硬性蛋白,在动物饲料、复合材料、食品包装和医药制品等领域展现出良好应用前景。但因羽毛角蛋白难溶解和降解的特殊性,一般方法很难获得可溶性角蛋白,酶法相对于传统物理和化学降解法具有反应条件温和、环境污染小和降解产物稳定等优点,是具有很高实用价值的羽毛降解途径。文中重点介绍角蛋白酶对羽毛的降解作用,并概述物理、化学方法的降解原理以及角蛋白的综合利用。     

组合酶水解羽绒加工副产物工艺参数的优化

本研究旨在对来源于地衣芽孢杆菌CP-16的重组角蛋白酶和二硫键还原酶协同酶解羽绒加工副产品最佳工艺条件进行探讨。试验探讨角蛋白酶与二硫键还原酶组合水解羽毛角蛋白的适宜比例，并研究蒸汽压力处理时间、酶解时间、组合酶添加水平和水分含量等单一因素对酶解效率的影响，再利用L9（3⁴）正交试验进一步优化处理工艺条件。结果显示，当角蛋白酶与二硫键还原酶的酶活比例为80：1，角蛋白酶终浓度为90 U/mL时，组合酶酶解羽绒加工副产品效率最佳；经压力处理2 h更有利于提高酶解效率；水解60 h酶解率最高，但与48 h差异不显著（P>0.05）；总反应体系中缓冲液为5.5 mL时酶解效率显著高于对照组（P<0.05），但与4.5 mL组差异不显著（P>0.05）。正交试验优化酶解羽绒加工副产品条件发现，影响组合酶酶解效率的因素由大到小依次为压力处理时间、酶解时间、酶剂量；酶解羽绒加工副产品最适条件为：角蛋白酶与二硫键还原酶活性比例为80：1，121℃高压处理2 h，角蛋白酶终浓度为90 U/mL，50℃酶解48 h，此时1 g羽绒加工副产品产生的上清液可溶性蛋白含量为352.72 mg，比对照组提高640.26%。综上，利用多种处理工艺相结合更有利于提高组合酶水解羽绒加工副产品的效率。本试验结果可为羽绒加工副产品资源开发利用提供理论指导。     

Optimization of Process Parameters of Hydrolyzed By-product of Combined Enzyme Down Processing

The aim of this study was to explore the optimal technological conditions for the synergistic enzymatic hydrolysis of feather processing by-products by recombinant keratinase and disulfide bond reductase from Bacillus licheniformis CP-16.Firstly,the appropriate proportion of keratinase and disulfide bond reductase was explored in this experiment.Secondly,the factors affecting the treatment of combined enzymes were studied,including steam pressure treatment time,enzymatic hydrolysis time,combined enzyme addition level and water content.Finally,L9(3⁴) orthogonal test was used to further optimize the processing conditions.The results were as follows:When the enzyme activity ratio of keratinase and disulfide bond reductase was 80：1 and the final concentration of keratinase was 90 U/mL,the combined enzyme had the best efficiency in feather hydrolysis.Pressure treatment of feather keratin for 2 h was more conducive to hydrolysis of feathers processing by-products by combined enzymes.Feather hydrolysis rate was the highest at 60 h hydrolysis,but it was not significantly different from that at 48 h (P>0.05).The efficiency of feather enzymatic hydrolysis in the total reaction system with 5.5 mL buffer was significantly higher than control group(P<0.05),but the difference was not significant compare to the group with 4.5 mL buffer (P>0.05).The results of orthogonal test showed that,the factors affecting the hydrolysis efficiency were pressure treatment time,enzymolysis time and enzyme dosage from large to small.The optimal conditions for feather enzymatic hydrolysis were:The ratio of keratinase to disulphide bond reductase was 80：1,121 ℃ for 2 h,the final concentration of keratinase was 90 U/mL,and the enzymatic hydrolysis was conducted at 50 ℃ for 48 h.At this condition,the soluble protein content of supernatant produced of each gram feather was 352.72 mg,which was 640.26% higher than that of the control group.In conclusion,the combination of multiple treatment processes was more conducive to improving the efficiency of hydrolysis of feathers processing by-products by combined enzymes.The study could provide guidance for the development and utilization of feather resources.     

Acantholytic folliculitis and epidermitis associated with Staphylococcus hyicus in a line of white Leghorn laying chickens

Several mature Leghorn-type hens with the same genetic background experienced skin and feather problems in a breeder flock. There was almost-total feather loss on the head and neck, as well as thickened, scaly skin, and follicular ostia were plugged with keratin debris. Other individuals exhibited prominent subcutaneous nodules multifocally on the head. Histologic examination of the skin revealed a severe hyperplasia of follicular epithelium with hyperkeratosis and cystic dilation. Numerous clefts and vesicles were detected along the epidermis and follicular epithelium, some containing acantholytic keratinocytes. A mild heterophilic inflammation was associated with these lesions, and few gram-positive cocci were present in the keratin plugs. Bacterial culture of the skin yielded a variable amount of Staphylococcus hyicus. Immunochemistry looking for chicken IgY revealed no intercellular staining in the epidermis or follicular epithelium. All these findings supported a diagnosis of Staphylococcus-associated acantholytic epidermitis and folliculitis. This case suggests that S. hyicus could be a significant pathogen in poultry production. The close genetic relationship among affected individuals could indicate a hereditary predisposition in this line of White Leghorn laying chickens.