Effect of Yeast Culture and Direct-Fed Microbes on the Growth Performance and Rumen Fermentation of Weaner Lambs

The effects of yeast culture and directfed microbes on the growth performance of weaner lambs was examined. Thirty-two Hu lambs with inihtial weight of 22.20 （ ±0.75 ） kg were randomly assigned to one of four treatments： basal diet without additive （control）, added with yeast culture at 15 g/head/d （YEC）, YEC plus Bacillus licheniformis preparation at 2. 3 g/head/d （YBL） or plus Clostridium butyricum preparation at 2. 3 g/head/d （YCB）. The feeding trial lasted 75 d with 15 d for adaptation. Feed intake was not influenced （P 〉0. 05） by treatment. Average daily gain of growing lambs was 102, 114, 90, and 89 g/d in control, YEC, YBL, and YCB, respectively, with no significant difference （P 〉 0.05） among treatments, but the carcass weight of YEC lambs was significantly higher （P 〈 0.05） than that of other treatments. Total volatile fatty acids and acetate to propionate ratio in the rumen were unaffected, although the butyric acid concentration was higher （ P 〈 0.05 ） in the ru men fluid of YCB lambs compared with YEC lambs and slightly higher （ P 〉 0. 05 ） than in controls and YBL lambs. Solid-associated fungi population relative to total rumen bacteria 16S ribosomal DNA was significantly lower （ P 〈 0. 05 ） in YBL lambs （3.55） compared with those on YCB （23.12）. There was little difference in blood glucose and plasma urea-N concentrations among the treatments. Blood concentrations of creatinine and globulin were significantly higher （P 〈0.05） in YBL lambs, compared with the control and YEC-fed animals, and no difference with YCB lambs. Total protein and triglycerides in blood were significantly （P 〈 0.05） higher in YBL lambs, compared with controls. These serum biochemical parameters suggest that treatment increased amounts of absorbable protein but not efficiency of protein utilization and in YBL and YCB lambs. The results indicated that yeast culture improve growth performance, while little advantage could be expected from combining yeast culture with either the B. licheniformis preparation or C. butyricum preparation. More research using lower doses of B. licheniformis prepara- tion or C. butyricum preparation in combination with yeast culture is warranted.

Effect of Indigenous Phytase-Producing Yeast Cultures on Growth Performance, Digestion and Health of Rabbits (Oryctolagus cuniculus)

This study investigated the effects of dietary supplementation of indigenous phytase producing live yeast cultures on growth performance, phytate degradation and blood biochemical parameters of weanling rabbits. Fifty-six rabbits (28 males and 28 females) were allotted randomly into four groups containing a control and three groups administrated each with the yeasts Saccharomyces cerevisiae ADR1B1, Hanseniaspora jakobsenii ADR3E1, Hanseniaspora guilliermondii RD31 during 8 weeks. The results showed that the administration of the three yeast strains accelerated the weight gain and improved rabbits growth performance in comparison to the control group, but did not affect the serum biochemical and hematological parameters. The highest weight gain (1715.95 ± 236 g), and phytate degradation rate (73.82% ± 0.92%) and the lowest biochemical parameters (triglycerides, cholesterol, HDL and LDL) were observed on rabbits fed with the yeast Hanseniaspora jakobsenii ADR3E1. This indigenous yeast species, which is used for the first time in animal feeding provided the best beneficial effects in rabbit breeding. Therefore, based on this finding, Hanseniaspora jakobsenii ADR3E1 can be recommended to supplement rabbit diets for growth performance and profitability enhancement.

Effects of different forms of yeast Saccharomyces cerevisiae on growth performance,intestinal development,and systemic immunity in early-weaned piglets

The present study was conducted to determine effects of different forms of yeast （Saccharomyces cerevisiae, strain Y200007） on the growth performance, intestinal development, and systemic immunity in early-weaned piglets. A total of 96 piglets （14-d old, initial average body weight of 4.5 kg） were assigned to 4 dietary treatments： （1） basa diet without yeast （Control）; （2） basal diet supplemented with 3.00 g/kg live yeast （LY）; （3） basal diet supplemented with 2.66 g/kg heat-killed whole yeast （HKY）; and （4） basal diet supplemented with 3.00 g/kg superfine yeast powders （SFY）. Diets and water were provided ad libitum to the piglets during 3-week experiment. Growth performance of piglets was measured weekly. Samples of blood and small intestine were collected at days 7 and 21 of experiment. Dietary supplementation with LY and SFY improved G：F of piglets at days ]-21 of the experiment （P 〈 0.05） compared to Control group. Serum concentrations of growth hormone （GH）, triiodothyronine （T3）, tetraiodothyronine （T4）, and insulin growth factor 1 （iGF-1） in piglets at day 21 of the experiment were higher when fed diets supplemented with LY and SFY than those in Control group （P 〈 0.05）. Compared to Control group, contents of serum urea nitrogen of piglets were reduced by the 3 yeast-supplemented diets （P 〈 0.05）. Diets supplemented with LY increased villus height and villus-to-crypt ratio in duodenum and jejunum of piglets （P 〈 0.05） compared to other two groups at day 7 of the experiment. Feeding diets supplemented with LY and SFY increased （P 〈 0.05） serum concentrations of IgA, IL-2, and IL-6 levels in piglets compared to Control. The CD4＋/CD8＋ ratio and proliferation of T-lymphocytes in piglets fed diets supplemented with LY were increased compared to that of Control group at day 7 of the experiment （P 〈 0.05）. In conclusion, dietary supplementation with both LY and SFY enhanced feed conversion, small intestinal development, and systemic immunity in early-weaned piglets, with better improvement in feed conversion by dietary supplementation with LY, while dietary supplementation with SFY was more effective in increasing systemic immune functions in early-weaned piglets.

Supplementation of Yeast Extract to Practical Diet Improves the Growth, Anti-Oxidative Capacity and Intestinal Morphology of Shrimp Litopenaeus vannamei

Two control diets based on the commercial formula were designed to contain high(27%,D1)and low(22%,D2)levels of fish meal,respectively.Into D2,500,1000 and 1500 mg kg 1 of yeast extract were added,respectively,yielding three experimental diets(YE1 through YE3).Shrimp(initial body weight 0.30 g±0.02 g)were fed with the experimental diets,five tanks each diet and 30 shrimp individuals each tank,for 8 weeks,and then challenged with Vibrio parahaemolyticus.The results showed that the specific growth rate(SGR)of shrimp in D2 was significantly lower than that of shrimp in D1(P<0.05).The SGR of shrimp in YE3 was similar to that of shrimp in D1.The feed intake of shrimp was similar between D1 and D2.The feed conversion ratio and protein efficiency ratio of shrimp were similar among all diets(P>0.05).YE significantly improved the activity of glutathione S-transferase.The concentration of glutathione(GSH)and the total serum anti-oxidative capacity(T-AOC)of D1 were significantly higher than those of shrimp feeding other diets(P<0.05).The content of serum malondialdehyde of shrimp feeding YE2 and YE3 was signifi-cantly lower than that of shrimp feeding D2(P<0.05).The thickness of intestine muscular layer of shrimp feeding YE1 and YE2 was similar to that of shrimp feeding D1.The shrimp feeding YE1 showed the highest villus height of intestine among all groups.The cumulative mortality after challenging was similar among all groups(70.00%86.67%)(P>0.05).In conclusion,1000 1500 mg kg 1 of YE was suggested to be supplemented into the practical diets to improve the growth,anti-oxidative capacity and intestinal mor-phology of shrimp L.vannamei.

Micro-environmentally Restricted Yeast Cell Growth within Ca-alginate Microbeads

Micro-environmental restriction effects to yeast cell growth obtained within Ca-alginate microbeads are considered. It is complex phenomenon influenced by: (1) relaxation of expanded polymer network around the cellular clusters, (2) forces generated by cell growth inside the beads and (3) interactions between solvent, network parts and cells. The resulting effects are measured experimentally by estimating volume of microbeads and yeast cell concentration as function of time of cultivation. Comparative analysis of dynamics of cell growth and increase of microbead volume through four regimes indicates that reversible and irreversible local structural changes of Ca-alginate hydrogel induces micro-environmental restrictions to cell growth. The mechanism of restrictions includes both mechanical and electrostatic effects.

Physiologicalandbiochemicalcharacteristicsofactivedryyeast

建立一种酿酒活性干酵母生理活性的简易评价方法，比较并筛选一株适合以木薯粉水解液发酵发酵生产燃料酒精的活性干酵母。优化2株酿酒活性干酵母的活化条件、生长温度和生长pH值，以木薯粉水解液为发酵液，在最适生长条件下比较两株酵母的生长曲线、发酵强度、耐糖能力、耐温能力和耐酒精能力。选择酿酒活性干酵母Ⅰ作为木薯粉水解液发酵酵母，该酵母在前36h发酵强度高于1g／（L．h），36h）后发酵强度迅速下降；耐糖能力为20％，耐受温度是55℃以及耐酒精浓度是7％。

Yeast Culture饲料添加剂菌体生长动力学

在不同温度、不同pH值、不同培养基组成以及通风条件下,研究了美国Dgiamond V Mills公司Yeast Culture饲料添加剂菌体的生长动力学,求出了各种条件下菌体生长的动力学参数,找出了菌体生长的最适温度为29℃,最适pH为5.3,为大规模生产该种饲料添加剂进行优化控制奠定了基础。

Nonphytate Phosphorus Requirement and Efficacy of a Genetically Engineered Yeast Phytase for Yellow Broilers at 22- to 42-d-Old Age

An experiment was conducted to investigate the requirement of nonphytate phosphorus（nPP） and efficacy of a genetically engineered yeast phytase（PHY A） for Lingnan yellow broilers from 22-to 42-d-old age.A total of 1 320 1-d-old male chicks were randomly divided into 11 dietary treatment groups,which consisted of 4 replicate floor pens with 30 birds per pen.The control group（treatment 1） was fed with basal diet of nPP 0.08% without dicalcium phosphate or phytase supplementation.Dietary levels of nPP were 0.16,0.24,0.32,0.40,0.48,and 0.56%,respectively,for treatments 2 to 7,through addition of dicalcium phosphate（chemistry grade） to the basal diet.Diets of treatments 8 to 11 were supplemented with PHY A at 200,400 and 600 U kg-1,a commercial phytase product（PHY B） at 400 U kg-1 level,respectively.The birds in 0.32-0.56% nPP groups gained more than those of the other groups（P0.05）.The nPP supplementation significantly improved feed intake（P0.05）.The feed gain ratio was significantly decreased by 0.40% nPP diet compared to the control birds（P0.05）.The level of 0.48% nPP was required for optimum tibia development.The additions of PHY A at 400 and 600 U kg-1 level and PHY B all significantly improved ADG（P0.05）,ADFI（P0.05）,and dry defatted tibia weight（P0.05）.Similarly,the percentage of tibia ash was increased by 600 U kg-1 PHY A supplementation（P0.05）.The requirement of nPP for maximal ADG and highest percentage tibia ash both was 0.40%.The phosphorus equivalency value of PHY A was estimated as 685 U kg-1 for male yellow broilers of 22-to 42-d-old age.

酵母硒对肉羊生长性能及肉品质的影响

试验旨在探究饲粮中添加不同水平的酵母硒对肉羊生长性能及肉品质的影响。选择体重相近、健康的肉羊50只,随机分为5个组,每组10个重复,每个重复1只肉羊。各组肉羊依次饲喂含有0(对照组)、0.1、0.2、0.4、0.8 mg/kg酵母硒的试验饲粮。预试期7 d,正式试验期56 d。结果显示,与对照组相比,饲粮中添加0.2 mg/kg、0.4 mg/kg的酵母硒显著增加了肉羊的末重、平均日增重、宰前活重、胴体重、净肉重、屠宰率及GR值(P<0.05),降低了料重比(P<0.05);0.1、0.2、0.4 mg/kg的酵母硒显著提高了净肉率(P<0.05)。与对照组相比,0.2 mg/kg和0.4 mg/kg的酵母硒显著提高肉羊屠宰24 h后的pH值(P<0.05),降低滴水损失(P<0.05);0.1、0.2、0.4 mg/kg酵母硒显著提高肉色红度(P<0.05);0.2、0.4和0.8 mg/kg的酵母硒显著降低肌肉剪切力(P<0.05),增加肌肉粗蛋白含量(P<0.05)。研究表明,饲粮中添加酵母硒可以提高肉羊的生长性能、产肉性能及肉品质,酵母硒适宜的添加水平为0.2~0.4 mg/kg。

酵母硒对肉鸡生长性能、屠宰性能、肉品质和抗氧化性能的影响

旨在探讨酵母硒对肉鸡生长性能、屠宰性能、肉品质和抗氧化性能的影响。选取150只1日龄白羽公肉鸡,随机分成5组,每组6个重复,每个重复5只,对照组以玉米-豆粕为基础饲料,各试验组Ⅰ、Ⅱ、Ⅲ、Ⅳ分别添加0.1、0.2、0.3和0.4 mg/kg的酵母硒,预试期7 d,正式试验期42 d。结果显示:添加酵母硒的各试验组对生长性能和屠宰性能均无显著影响(P>0.05)。在肉品质方面,试验Ⅲ组和试验Ⅳ组的红度(a^(*))值和宰后45 min的pH值均显著高于对照组(P<0.05);试验Ⅱ组、试验Ⅲ组、试验Ⅳ组宰后24 h的pH值与对照组相比有显著提高(P<0.05)。在抗氧化性能方面,试验Ⅳ组的超氧化物歧化酶(SOD)活性极显著高于其他各组(P<0.01),试验Ⅱ组和试验Ⅲ组的过氧化氢酶(CAT)活性显著高于对照组(P<0.05),试验Ⅲ组谷胱甘肽过氧化物酶(GSH-Px)活性极显著高于其他各组(P<0.01)。提示:肉鸡日粮添加酵母硒的最适宜添加量为0.3 mg/kg。

酵母硒对肉仔鸡生长性能、屠宰性能及血清抗氧化指标的影响

文章旨在研究酵母硒对肉仔鸡生长性能、屠宰性能及血清抗氧化指标的影响。试验将1600羽1日龄的白羽肉鸡随机分为4组,每组8个重复,每个重复50羽。试验分1~21 d和22~42 d两阶段进行饲养,试验日粮分别添加0、0.1、0.2和0.4 mg/kg酵母硒。结果表明:1~21 d,与对照组相比,0.2 mg/kg的酵母硒组肉鸡末体重(FBW)显著提高5.59%,平均日增重(ADG)显著提高5.80%,料重比显著降低5.93%(P<0.05);22~42 d,与对照组相比,0.2 mg/kg酵母硒组肉鸡FBW显著提高4.25%,ADG显著提高3.62%(P<0.05);1~42 d,与对照组相比,0.2 mg/kg酵母硒组肉鸡ADG显著提高4.29%,料重比显著降低4.66%(P<0.05);此外,酵母硒对肉鸡全阶段ADFI均无显著影响(P>0.05)。0.2mg/kg酵母硒组肉鸡屠宰率显著提高(P<0.05);0.2mg/kg酵母硒组肉鸡胸肌率显著提高(P<0.05);0.2和0.4 mg/kg的酵母硒组肉鸡腿肌滴水损失显著降低(P<0.05);0.2 mg/kg酵母硒组肉鸡腿肌亮度显著降低(P<0.05)。21 d,0.2和0.4mg/kg酵母硒组肉鸡血清总超氧化物歧化酶(T-SOD)和总抗氧化能力(T-AOC)活性显著提高(P<0.05),丙二醛(MDA)含量显著降低(P<0.05),0.2 mg/kg酵母硒组肉鸡血清谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(P<0.05);42 d,0.2和0.4mg/kg酵母硒组肉鸡血清谷胱甘肽过氧化物酶(GSH-Px)活性显著提高(P<0.05),0.2 mg/kg酵母硒组肉鸡血清丙二醛(MDA)含量显著降低(P<0.05)。综上所述,本试验发现,添加0.2 mg/kg的酵母硒可通过提升肉鸡血清抗氧化能力促进肉鸡生长发育。

饲料中添加酵母培养物对大口黑鲈生长、肠道健康和免疫力的影响

研究旨在探究饲料中添加酵母培养物“水产益康”对大口黑鲈(Micropterus salmoides)生长性能、肠道健康、免疫力和病菌攻击后存活率等方面的影响,在基础对照饲料中添加质量分数0.1%和0.3%的酵母培养物“水产益康”(分别为0.1%添加组和0.3%添加组),配置3种等氮等脂的实验饲料。将360尾初始质量为(32.37±0.15)g的大口黑鲈分为3个处理,每个处理设3个重复,每个网箱放养40尾鱼,生长实验周期为11周。结果表明:两个添加组的生长性能与对照组相比没有显著差异(P>0.05);在肠道结构方面,0.3%添加组的绒毛长度较对照组显著增加,隐窝深度较对照组显著下降(P<0.05);在肠道微生物方面,两个实验组均较对照组降低了肠道内蓝藻门(Cyanobacteria)及葡萄球菌(Staphylococcus)含量,提高了肠道内梭菌目(Clostridiales)含量;在头肾生化指标方面,0.3%添加组较对照组显著提高了头肾超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和碱性磷酸酶(AKP)活性及溶菌酶(LZM)含量,0.1%添加组也较对照组显著提高了头肾SOD和AKP活性(P<0.05);在血浆生化指标方面,0.3%添加组较对照组显著降低了血浆丙二醛(MDA)含量(P<0.05),SOD活性也有所提高,但没有显著性差异(P>0.05);嗜水气单胞菌(Aeromonas hydrophila)攻毒结果显示,攻毒后两实验组的累计存活率较对照组升高,在252h以后有显著区别(P<0.05)。以上结果表明,饲料中添加0.1%—0.3%培养物对大口黑鲈肠道健康、抗氧化能力、免疫和抗病力有积极作用。

酵母复合微生态制剂对鲤鱼生长性能、免疫指标及抗氧化能力的影响

本试验旨在研究饲料中添加酵母复合微生态制剂对鲤鱼生长性能、免疫指标及抗氧化能力的影响,并确定其适宜的添加量。选用初始体重为(35±0.5)g的鲤鱼540尾,随机分为6组,每组3个重复,每个重复30尾鱼,预饲14 d。以基础日粮为CK组,试验组分别饲喂含0.1‰、0.5‰、1‰、2‰、3‰酵母复合微生态制剂饲料,饲养56 d后采样分析。结果表明:(1)与CK组相比,饲料中添加酵母复合微生态制剂可显著提高鲤鱼的生长性能,2‰、3‰组增重率(WGR)增加了23.01%、24.15%(P<0.05),特定生长率(SGR)增加了13.79%、14.37%(P<0.05),饲料系数(FCR)降低了18.09%、18.59%(P<0.05)。(2)与CK组相比,饲料中添加酵母复合微生态制剂可显著提高鲤鱼的免疫指标,2‰、3‰组溶菌酶(LSZ)提高了47.9%、48.74%(P<0.05),免疫球蛋白M(IgM)提高了48.31%、49.44%(P<0.05),补体C3(C3)提高了39.61%、39.61%(P<0.05),碱性磷酸酶(AKP)提高了17.05%、17.44%(P<0.05),总蛋白(TP)提高了31.03%、30.38%(P<0.05)。(3)与CK组相比,饲料中添加酵母复合微生态制剂可显著提高鲤鱼的抗氧化能力,2‰、3‰组总抗氧化能力(T-AOC)提高了41.69%、41.36%(P<0.05),超氧化物歧化酶(SOD)提高了37.63%、45.71%(P<0.05),过氧化氢酶(CAT)提高了41.69%、41.36%(P<0.05),丙二醛(MDA)降低了22.71%、20.92%(P<0.05)。由此得出,饲料中添加2‰、3‰酵母复合微生态制剂能够显著提高鲤鱼的生长性能、血清免疫指标及肝脏抗氧化能力。基于2‰、3‰添加量组各指标差异不显著,建议酵母复合微生态制剂的最佳添加剂量为2‰。

饲粮中添加活性酵母对生长肉兔生长性能、肉品质和肠道菌群的影响

本试验旨在研究饲粮中添加活性酵母对生长肉兔生长性能、肉品质和肠道菌群的影响。选取体重相近的健康35日龄断奶仔兔360只,随机分为3组,每组6个重复,每个重复20只仔兔。对照组饲喂基础饲粮(不添加活性酵母),试验组分别在基础饲粮中添加500和1000 g/t的活性酵母。试验期34 d。结果表明:1)与对照组相比,饲粮中添加500和1000 g/t活性酵母显著提高了生长肉兔的成活率(P<0.05),显著降低了生长肉兔的平均日采食量(P<0.05)。2)与对照组相比,饲粮中添加500 g/t活性酵母显著提高了肌肉滴水损失(P<0.05),饲粮中添加1000 g/t活性酵母显著降低了肌肉滴水损失(P<0.05)。3)与对照组相比,饲粮中添加1000 g/t活性酵母显著提高了盲肠微生物的Simpson指数(P<0.05);在门水平上,饲粮中添加1000 g/t活性酵母提高了盲肠厚壁菌门(Firmicutes)的相对丰度;在属水平上,饲粮中添加1000 g/t活性酵母提高了盲肠未分类鞭毛虫菌科(norank_f_Lachnospiraceae)、未分类鼠杆菌科(norank_f_Muribaculaceae)、毛螺旋菌科NK4A136群(Lachnospiraceae_NK4A136_group)、未分类梭状芽孢杆菌属vadinBB60群(norank_f_norank_o_Clostridia_vadinBB60_group)的相对丰度。4)属水平上组间物种差异分析显示,与对照组相比,饲粮中添加500和1000 g/t活性酵母显著降低了盲肠互养菌属(Synergistes)的相对丰度(P<0.05),饲粮中添加500 g/t活性酵母显著提高了盲肠厌氧管菌属(Anaerostipes)的相对丰度(P<0.05),饲粮中添加1000 g/t活性酵母显著提高了盲肠芽孢杆菌属(Bacillus)的相对丰度(P<0.05)。综上所述,饲粮中添加500和1000 g/t活性酵母能够提高生长肉兔的成活率,降低平均日采食量;饲粮中添加1000 g/t活性酵母能降低生长肉兔肌肉滴水损失,从而改善肉质;饲粮中添加1000 g/t活性酵母能改善生长肉兔肠道菌群结构,有助于肠道健康。

酵母硒联合枯草芽孢杆菌对肉羊生长性能、瘤胃发酵及屠宰性能的影响

本文旨在研究酵母硒(Yeast Selenium,YS)联合枯草芽孢杆菌(Bacillus Subtilis,BS)对肉羊生长性能、瘤胃发酵及屠宰性能的影响。试验将60只日龄和体重相近的杜寒杂交羊随机分为4组,每组3个重复,每个重复5只。其中,CON组肉羊饲喂基础日粮,YS组肉羊饲喂基础日粮+100 mg/kg酵母硒,BS组肉羊饲喂基础日粮+30 mg/kg枯草芽孢杆菌,YS+BS组肉羊饲喂基础日粮+100 mg/kg酵母硒+30 mg/kg枯草芽孢杆菌。试验为期72 d,预饲期7 d,正试期65 d。结果显示:(1)与CON组相比,YS+BS组肉羊的末重显著提高5.25%(P<0.05),平均日增重显著提高15.93%(P<0.05)。与CON组相比,YS组、BS组、YS+BS组肉羊的料重比分别显著下降7.18%、6.20%、12.72%(P<0.05)。(2)与CON组、YS组相比,BS组、YS+BS组肉羊瘤胃pH值显著降低(P<0.05),乙酸含量和乙丙比显著提高(P<0.05)。与CON组相比,BS组、YS+BS组肉羊瘤胃氨态氮浓度显著提高(P<0.05)。(3)与CON组相比,YS+BS组肉羊的宰前活重、胴体重、眼肌面积显著提高5.38%、7.49%、17.37%(P<0.05)。由此可见,酵母硒联合枯草芽孢杆菌能提高肉羊生长性能,改善瘤胃发酵及屠宰性能。

活性干酵母对晋岚绒山羊生长性能、屠宰性能及血清生化指标的影响

【目的】研究活性干酵母对晋岚绒山羊生长性能、屠宰性能及血清生化、免疫和抗氧化指标的影响,选出适宜的活性干酵母添加量。【方法】选取100只3月龄晋岚绒山羊公羔开展育肥试验,随机分为5组,每组20只,每个重复4只。试验组ADY1、ADY2、ADY3和ADY4每只羊在基础饲粮基础上分别补饲1、2、3、4 g/d活性干酵母,对照组(ADY0)羊不添加活性干酵母。预试验15 d,正试验90 d,每30 d进行生长性能及血清生化、免疫和抗氧化指标测定,第90天进行屠宰性能测定。【结果】与对照组相比,(1)ADY3和ADY4组羊终末体重显著升高(P<0.05),料比重显著降低(P<0.05);第90天时,ADY3组羊胸围和体长均显著增加(P<0.05),ADY4组羊胸围显著增加(P<0.05)。(2)ADY3和ADY4组羊宰前活重、胴体重和眼肌面积均显著增加(P<0.05),胴体脂肪含量和背膘厚均显著降低(P<0.05);ADY2、ADY3和ADY4组羊净肉重和净肉率均显著增加(P<0.05),ADY3和ADY4组羊心脏重均显著升高(P<0.05)。(3)第30、60、90天,4个试验组羊血清中甘油三酯(TG)含量均显著升高(P<0.05);ADY3组第30天羊总胆固醇(TC)含量显著降低(P<0.05);第90天时,ADY2和ADY3组羊总蛋白(TP)和球蛋白(GLB)含量均显著增加(P<0.05)。(4)第60、90天时,ADY3组羊免疫球蛋白A(IgA)和肿瘤坏死因子-α(TNF-α)含量均显著升高(P<0.05)。(5)第60天时,ADY3组羊总抗氧化能力(T-AOC)和超氧化物歧化酶(SOD)活性均显著升高(P<0.05);第60、90天时,ADY3组羊丙二醛(MDA)含量均显著降低(P<0.05)。(6)第90天时,ADY2和ADY3组羊血清中胰岛素生长因子-1(IGF-1)含量显著增加(P<0.05)。【结论】在饲料中添加适量活性干酵母可以提高晋岚绒山羊的生长性能和屠宰性能,增强免疫力及抗氧化能力,综合考虑,添加2~3 g/d较为适宜。

酵母水解物对克氏原螯虾生长性能、消化、抗氧化和免疫能力的影响

实验研究了添加不同水平酵母水解物(Yeast hydrolysate,YHY)对克氏原螯虾(Procambarus clarkii)生长性能、消化、抗氧化和非特异性免疫能力的影响。实验选用300尾平均体重为(6.43±0.55)g的个体,随机分为5组,分别饲喂在基础饲料中添加0(对照组)、0.5%、1%、2%和4%YHY的饲料,每组3个重复,养殖密度为20尾/缸。为期8周的实验结束后,测定克氏原螯虾生长指标、胃和肝胰腺消化酶活性、肝胰腺抗氧化性能、血清生化指标和免疫酶活性。结果表明:(1)饲料中添加1%—4%YHY对该虾生长指标有促进作用。其中,2%添加组的存活率(SR)、最终体重(FBW)、最终体长(FBL)和肝胰腺指数(HSI)达最大值且显著高于对照组(P<0.05),增重率(WGR)和特定生长率(SGR)在1%添加组达到最大值且显著高于其余各组(P<0.05);(2)1%YHY添加组的全虾粗蛋白质含量显著高于其他组(P<0.05),而肌肉粗蛋白和粗脂肪含量在2%添加组达到最大值;(3)与对照组相比,2%—4%YHY添加组的胃和肝胰脏消化酶活性显著提高(P<0.05);(4)2%YHY添加组的肝胰腺抗氧化酶(过氧化氢酶,CAT;总超氧化物歧化酶,T-SOD;总抗氧化能力,T-AOC)和免疫酶(碱性磷酸酶,AKP;酸性磷酸酶,ACP)的活性达到最大值、丙二醛(MDA)的含量达到最小值,且与对照组相比均有显著差异(P<0.05);(5)2%YHY添加组该虾血清中总蛋白(TP)和白蛋白(ALB)含量显著高于其他组(P<0.05),1%和2%YHY添加组谷丙转氨酶(ALT)和谷草转氨酶(AST)活性显著低于其他各组(P<0.05)。结果表明,饲料中添加2%的酵母水解物可显著提高克氏原螯虾的消化、生长及肌肉粗蛋白和粗脂肪含量,并显著改善其抗氧化和非特异性免疫能力。

不同微生物制剂对大口黑鲈生长、形体指标及肠道组织结构的影响

为探究不同微生物制剂对大口黑鲈生长、形体指标及肠道组织结构的影响,在商业配合饲料中添加不同浓度的丁酸梭菌[0(A组,CK)、0.25%(B组)、0.5%(C组)、1%(D组)丁酸梭菌(5×10^(8) cfu·g^(-1))]、0.2%酵母产品(E组)及两者的混合物(0.25%丁酸梭菌+0.2%酵母产品,F组)进行两阶段共17周的养殖试验。结果表明:第一阶段(14周)试验组中,除添加0.2%酵母产品(E组)外,其余均较对照显著提升了大口黑鲈的生长性能,其中添加0.5%丁酸梭菌效果最优;第二阶段(17周)试验组间(A、C和F组),0.5%丁酸梭菌(C组)和0.25%丁酸梭菌+0.2%酵母产品(F组)的末均重及末体长较对照A组均显著增加;肥满度、脏体比指数、肠绒毛长度及肌层厚度三组间无显著差异,但与对照(A组)相比,添加0.5%丁酸梭菌(C组)的各指标有增高趋势,添加0.25%丁酸梭菌+0.2%酵母产品(F组)的各指标有降低趋势。研究表明,在本试验条件下,商业配合饲料中添加0.5%丁酸梭菌对大口黑鲈生长及肠道健康改善的效果最佳。

醋源生香酵母的筛选及其特性研究

为解决食醋香气弱、香气不稳定问题,提升食醋风味品质,该文以醋醅和醋曲为菌源,对分离菌株采用嗅闻法、皂化法及顶空固相微萃取气质联用(headspace solid phase microextraction-gas chromatograph-mass spectrometry,HS-SPME-GC-MS)法筛选高产酯(生香)酵母菌株并进行种属鉴定,进而研究其生长及产酯特性。结果表明,从20份醋源样品中分离101株酵母菌,利用嗅闻法发现36株菌产香气明显,皂化法发现6株菌产酯能力较强,其中,菌株D13-Y2产酯能力突出,在发酵液中总酯产量为(3.50±0.07)g/L,HS-SPME-GC-MS测定出该菌可产挥发性香气成分59种,其中包含酯类物质有22种、醇类9种、酸类4种、酮类2种、醛类1种、酚类1种、其他物质20种。经鉴定,该菌株为异常威克汉姆酵母(Wickerhamomyces anomalus),其最适培养条件为:28℃、pH 4.5、18 h,有较好的酒精耐受能力;其最适产酯条件为:发酵温度20℃、接种量(体积分数)3%、发酵时间4 d;分别添加体积分数1%的乙醇、体积分数0.1%的乙酸时总酯产量可分别提高10.32%[总酯产量达(3.74±0.01)g/L]、13.15%[总酯产量达(4.03±0.04)g/L]。该研究结果旨在为改善麸醋风味品质提供了菌种资源和理论依据。

筒鲜鱼中优势酵母菌的筛选鉴定及其生长特性分析

筒鲜鱼作为信阳商城的地方风味名菜,因其独特的风味备受消费者青睐。酵母菌是影响发酵食品风味品质的关键因子,故选用发酵5 d、10 d、15 d的筒鲜鱼作为分离源,分离纯化酵母菌,考察分离菌株的发酵性能、分解蛋白质能力及产酯能力,筛选优良酵母菌。基于形态学观察、生理生化试验(糖发酵试验、同化试验)及26S r DNA基因序列对筛选菌株进行鉴定,并对其生长特性及最适培养条件进行分析。结果表明,从样品中共分离得到19株酵母菌,并从其中复筛出优良酵母菌株C14。经鉴定,菌株C14为解脂耶氏酵母(Yarrowia lipolytica)。菌株C14在8~24 h生长活跃,其最佳培养条件为温度28~36℃,盐浓度<5%,pH值为5,转速200 r/min。该研究结果可为筒鲜鱼的制剂化生产、标准化生产提供理论依据。