Dietary yeast RNA supplementation reduces mortality by Aeromonas hydrophila in rohu (Labeo rohita L.) juveniles

A feeding trial was conducted for 60 days to delineate the effect of dietary ribonucleic acid or chitin on haematological parameters, phagocyte respiratory burst and resistance to Aeromonas hydrophila of Labeo rohita juveniles. One hundred and twenty-six (avg. wt. 13.40 +/- 0.17 g) juveniles were randomly distributed in six treatment groups, each one in three replicates. Six isonitrogenous (crude protein: 34.34-35.37%) and isocaloric (414-425 kcal 100 g(-1)) purified diets were prepared with different concentrations of either ribonucleic acid or chitin except the control group, viz., control, T1 (0.1% ribonucleic acid), T2 (0.2% ribonucleic acid), T3 (0.4% ribonucleic acid), T4 (25 mg chitin kg (-1)) and T5 (50 mg chitin kg (-1)). Weight gain %, specific growth rate, feed efficiency ratio, protein efficiency ratio did not vary significantly (P > 0.05) among the experimental groups. Haemoglobin content and total erythrocyte count were observed within the normal range and were not influenced by the dietary immunostimulants. Highest total leukocyte count was found in the T(3) group. The immunomodulatory effects of dietary immunostimulants were studied by using nitroblue tetrazolium (NBT) assay and serum parameters, namely total protein, albumin, globulin and A/G ratio. The respiratory burst activity (NBT) of blood phagocytes was highest in the T3 group followed by the T2 group, which varied significantly (P < 0.05) from other groups. Significantly (P < 0.05) higher total protein, globulin and lower A/G ratio was observed in the T(3) group. The relative percent survival after challenging with Aeromonas hydrophila was highest in the T3 group, compared to the control group, followed by the T2 group. The results indicate that dietary ribonucleic acid at 0.4% enhances phagocyte respiratory burst and protection of Labeo rohita juveniles to challenge by A. hydrophila.     

Haemato-immunological responses to dietary yeast RNA, omega-3 fatty acid and beta-carotene in Catla catla juveniles

A preliminary study with 60 days feeding was conducted to study the immunomodulatory role of different immunostimulants like beta-carotene, omega-3 fatty acid and yeast-RNA in Catla catla fingerlings. Two hundred and sixty four fingerlings were randomly distributed into eight treatment groups with each of three replicates. Eight isonitrogenous (crude protein 34.12-35.40%) and isocaloric (458.41-461.48 kcal/100g) purified diets were prepared with graded level of beta-carotene, omega-3 fatty acid and yeast-RNA viz., Control (basal diet), T1 (Basal + 1% omega-3 fatty acid), T2 (Basal + 3% omega-3 fatty acid), T3 (Basal + beta-carotene), T4 (T1 + beta-carotene), T5 (T2 + beta-carotene), T6 (Basal + 0.4% yeast-RNA) and T7 (Basal + 0.8% yeast-RNA). The immunomodulatory effects of dietary immunostimulants were studied in terms of respiratory burst activity (NBT) of blood phagocytes, total leukocyte count, serum total protein, serum globulin, A/G ratio (A/G) and serum lysozyme activity. The respiratory burst activity of T7 group was significantly higher (p<0.05) than the other groups. Haemoglobin content, total erythrocyte count and serum albumin content did not vary among the treatment groups, whereas total leukocyte count, serum globulin content and serum lysozyme activity were found to be highest in T7 group. Relative survival percent after challenge with Aeromonas hydrophila was also highest in T7 (88.88%) group followed by T6 (75.06%) and T4 (66.66%) and the lowest in T2 group. It was observed that total leucocyte count, NBT and lysozyme activity of T2 group fed with high omega-3 fatty acid (3%) was less than (p<0.05) its lower counterparts T1 (1%) and control group. Based on the results of the present study, it concludes that supplementation of yeast-RNA at 0.8% registered higher immunological responses in C. catla juveniles. It is also observed that higher supplementation of omega-3 fatty acid (3%) in the diet causes immunosuppression in C. catla juveniles.     

Pre- and post-challenge immuno-haematological changes in Labeo rohita juveniles fed gelatinised or non-gelatinised carbohydrate with n-3 PUFA

The combined effect of dietary carbohydrate type and n-3 PUFA (EPA+DHA) on pre- and post-challenge haemato-immunological responses in Labeo rohita juveniles was studied. Fish were fed for 67days with six different test diets containing either gelatinised (G) or non-gelatinised (NG) corn (43%) with three levels of n-3 PUFA (0.5%, 1.0% and 2.0%). During the pre-challenge period, significantly higher (P<0.05) NBT, serum lysozyme activity, total protein and globulin content was recorded in the NG carbohydrate fed groups. Highest NBT value was recorded in the groups fed with 1.0% n-3 PUFA, whereas the highest serum lysozyme activity (P<0.05) was recorded at either 0.5% or 2.0% n-3 PUFA fed groups in both the pre- and post-challenge period. Feeding of NG corn significantly increased the total leucocyte count, lysozyme activity, A/G ratio and decreased the total erythrocyte count, haemoglobin, serum total protein and globulin content of L. rohita juveniles during the post-challenge period. Similarly, feeding of n-3 PUFA at any level significantly increased the immunological parameters like lysozyme activity or A/G ratio, whereas total leukocyte count increased due to feeding of either 0.5% or 1.0% n-3 PUFA. The NBT and albumin values remained similar in both the pre- and post-challenge period. After challenge with Aeromonas hydrophila, the highest survival was recorded in the NG carbohydrate fed groups, whereas the lowest survival was recorded in the highest level of n-3 PUFA fed group irrespective of dietary carbohydrate type. Thus, a high level of G carbohydrate as well as n-3 PUFA is found to be immunosuppressive in L. rohita juveniles. NG carbohydrate supplemented with 1.0% n-3 PUFA is found to be optimum to enhance the immunity in L. rohita juveniles.     

Enhanced innate immune parameters in Labeo rohita (Ham.) following oral administration of Bacillus subtilis

The present study assessed the use of Bacillus subtilis in fish as a probiotic. The bacterium was administered orally at three different doses 0.5 x 10(7) (T(2)), 1 x 10(7) (T(3)), 1.5 x 10(7) (T(4)) cfu/g feed to Labeo rohita for two weeks. The positive control group (T(1)) and negative control group (T(5,)) were fed feed without B. subtilis for the same period. On the 15th day blood and serum were sampled to determine respiratory burst activity (NBT assay), differential leukocyte counts (DLC) and serum bactericidal activity. Fishes were challenged intraperitoneally with Aeromonas hydrophila O:18 after two weeks in the treatment groups (T(2), T(3) and T(4)) and also in the positive control group(T(1)), while the negative control group (T(5)) was challenged with phosphate buffered saline (PBS, pH 7.2) only. The respiratory burst activity and DLC were assessed on the 3rd day post-challenge. B. subtilis treated fish showed significantly higher (P<0.05) respiratory burst activity and bactericidal activity during the pre-challenge compared with the control groups. The highest respiratory burst activity (0.37+/-0.03) and serum bactericidal activity were recorded in the group (T(4)) fed feed containing B. subtilis at 1.5 x 10(7)cfu/g feed. Granulocyte numbers were significantly higher (P<0.05) in treatment groups in comparison to the control in both the pre- and post-challenge periods. The result suggests that B. subtilis can enhance certain innate immune responses in rohu.     

Immunomodulation of Labeo rohita juveniles due to dietary gelatinized and non-gelatinized starch

A 60 days experiment was conducted to study the effect of dietary gelatinized (G) and non-gelatinized (NG) starch on immunomodulation of Labeo rohita juveniles. Two hundred and thirty four juveniles (av. wt. 2.53+/-0.04) were randomly distributed in six treatment groups with each of three replicates. Six semi-purified diets containing NG and G corn starch, each at six levels of inclusion (0, 20, 40, 60, 80, 100) were prepared viz., T(1) (100% NG, 0% G starch), T(2) (80% NG, 20% G starch), T(3) (60% NG, 40% G starch), T(4) (40% NG, 60% G starch), T(5) (20% NG, 80% G starch) and T(6) (0% NG, 100% G starch). After a feeding period of 60 days, the juveniles were challenged with Aeromonas hydrophila to study their immunomodulation due to feeding of G and NG starch. RBC and haemoglobin content were significantly (P<0.05) reduced due to bacterial challenge, but dietary starch (G/NG starch) had no effect on it. G:NG starch ratio in the feed had significant effect on total leukocyte count during pre- and post-challenge periods. The leukocyte count concomitantly increased with the increased level of G starch in the diet. Highest albumin/globulin (A/G) ratio was recorded in T6 group (100% G starch) and lowest in T1 group (100% NG starch) group followed by T2 group both in pre- and post-challenge periods. NBT, lysozyme activity, total protein and globulin content were highest in T2 group (80% NG, 20% G starch) both in pre- and post-challenge periods. After challenge with A. hydrophila, the highest survival was recorded in T2 group, whereas lowest survival was recorded in T6 group. Conclusively high level of G starch was found to be immunosuppressive in Labeo rohita juveniles and NG:G starch ratio of 80:20 seems to be optimum for promoting growth and protecting immunity in L. rohita juveniles.     

Antidiabetic activity of levan polysaccharide in alloxan-induced diabetic rats

This study aims to examine the effects of polysaccharide levan on oxidative stress and hyperglycemia in alloxan-induced diabetic rats. Levan, used in this study, was a microbial levan synthetisized by a non pathogenic bacteria recently isolated and identified as Bacillus licheniformis. Animals were allocated into four groups of six rats each: a control group (Control), diabetic group (Diab.), normal rats received levan (L) and diabetic rats fed with levan (DL). Treated diabetic rats were administrated with levan in drinking water through oral gavage for 60 days. The administration of polysaccharide levan in diabetic rats caused a significant increase in glycogen level by 52% and a decrease in glucose level in plasma by 52%. Similarly, the administration of polysaccharide levan in diabetic rats caused a decrease in the thiobarbituric acid-reactive substances (TBARS) by 31%, 41%, 39% and 25%, an increase in superoxide dismutase (SOD) by 40%, 50%, 44% and 34%, and in catalase (CAT) by 18%, 20%, 12% and 18% in liver, kidney, pancreas and heart, respectively. Furthermore, a significant decrease in hepatic and renal indices toxicity was observed, i.e. alkalines phosphatases (ALP), aspartate and lactate transaminases (AST and ALT) activities, total bilirubin, creatinine and urea levels by 19%, 31%, 32%, 36%, 37% and 23%, respectively. The results show that administration of polysaccharide levan can restore abnormal oxidative indice near normal levels. This study demonstrates, for the first time, that polysaccharide levan is efficient in inhibiting hyperglycemia and oxidative stress induced by diabetes and suggests that levan supplemented to diet may be helpful in preventing diabetic complications in adult rats.     

虹鳟幼鱼对不同淀粉的利用

试验旨在考察不同淀粉种类对虹鳟(Oncorhynchus mykiss)幼鱼生长性能、血清生化指标、肝脏糖代谢酶、肝脏组织学和摄食后血糖含量的影响。选用木薯淀粉、小麦淀粉、豌豆淀粉和玉米淀粉为淀粉源,设置相同的淀粉水平(15%),配制4组等氮等脂饲料,饲喂初始体重(7.7±0.1) g的虹鳟56d。结果表明,木薯淀粉组增重率最高(1049.3%),饲料系数最低(0.83)。各组脏体比、肝体比、全鱼和肝脏常规组成无显著差异(P>0.05);豌豆淀粉组肝糖原含量显著低于其他组(P<0.05)。各组血清甘油三酯、总胆固醇、谷草转氨酶和谷丙转氨酶无显著差异(P>0.05)。木薯淀粉组和小麦淀粉组肝脏己糖激酶活性显著高于豌豆淀粉组和玉米淀粉组(P<0.05),玉米淀粉组肝脏磷酸果糖激酶活性显著低于木薯淀粉组和小麦淀粉组(P<0.05)。摄食后,各组的血糖含量均在7h达到最高,木薯淀粉组在摄食后1—7h内的血糖含量显著高于其余3组(P<0.05)。各组的肝脏组织形态无显著差异。综上,木薯淀粉较其他3种淀粉更适宜作为虹鳟饲料的淀粉源。     

Dietary Korean mistletoe enhances cellular non-specific immune responses and survival of Japanese eel (Anguilla japonica)

The present study was performed to investigate the immunostimulatory effects of Korean mistletoe extract (KM-110; Viscum album Coloratum) on the non-specific immune response and protection against Aeromonas hydrophila infection in Japanese eel (Anguilla japonica). Eels were fed under 4 regimes, 0%, 0.1%, 0.5% and 1.0% KM-110 mixed diet. On day 14 after feeding, 15 fish from each group were injected i.p. with live A. hydrophila (3 x 10(6)CFU) and the remaining unchallenged fish from each group were used to study the innate immune response. On 14 days post-infection, the total survival rates were 26.6% in control, and 33.3%, 66.6% and 80% in 0.1%, 0.5% and 1% KM-110-treated groups, respectively. The maximum lysozyme activity was observed in the 1% KM-110-treated group. There was no significant difference of lysozyme activity between 0.1% and 0.5% KM-110 group. Superoxide anion (O(2)(-)) production was significantly (p<0.05) augmented in the 0.5% and 1% KM-110 groups compared to the control and 0.1% KM-110 group. No significant difference of (O(2)(-) production was found between 0.5% and 1% KM-110 group. Likewise, there was a significant increase in phagocytic activity in the 0.5% KM-110 group compared with the 0.1% group (p<0.05), but no significant difference between the 0.5% and the 1% KM-110 group indicating that 0.5% KM-110 concentration is suitable for stimulating maximum phagocytic activity resulting in a high amount of ROI production. Considering the present results, KM-110 could be utilized as a promising immunostimulating substance for a diet in aquaculture.     

Effect of dietary carbohydrate on haematology, respiratory burst activity and histological changes in L. rohita juveniles

A feeding trial was conducted for 60 days to delineate the effect of dietary carbohydrate on the haematology, respiratory burst activity and histology in Labeo rohita juveniles. One hundred and forty four fish (av. wt. 10+/-0.15 g) were randomly distributed into 12 treatment groups with each of two replicates. Twelve semi-purified diets with either 35% or 28% of crude protein were prepared with different amylase concentrations (0, 50, 100 and 150 mgkg(-1)) and starch type (gelatinised, G/non-gelatinised, NG) designated as T1 (NG, 35% CP, 0 mgkg(-1) amylase), T2 (G, 35% CP, 0 mgkg(-1) amylase), T3 (NG, 28% CP, 50 mgkg(-1) amylase), T4 (NG, 35% CP, 50 mgkg(-1) amylase), T5 (G, 28% CP, 50 mgkg(-1) amylase), T6 (G, 35% CP, 50 mgkg(-1) amylase), T7 (NG, 28% CP, 100 mgkg(-1) amylase), T8 (NG, 35% CP, 100 mgkg(-1) amylase), T9 (G, 28% CP, 100 mgkg(-1) amylase), T10 (G, 35% CP, 100 mgkg(-1) amylase), T11 (NG, 28% CP, 150 mgkg(-1) amylase) and T12 (NG, 35% CP, 150 mgkg(-1) amylase). The fish were acclimatised to the experimental conditions for 15 days during which time the control diet was fed. The blood haemoglobin percentage and RBC count was not significantly different (P>0.05) among the various treatments. Highest WBC count, total plasma protein, serum globulin and respiratory burst activity was found at 50 mgkg(-1) dietary amylase supplementation, whereas no variation (P>0.05) was found at 0, 100 and 150 mgkg(-1) dietary amylase supplementation. There was no difference (P>0.05) in the serum albumin and AG ratio among the experimental groups. Feeding either gelatinised or non-gelatinised carbohydrate did not affect the histological structure of the liver, kidney and intestine except in the T4 and T7 groups. The T4 group showed hyperplasia of the intestine and moderate vacuolation in hepatic cells, whereas the T7 group showed hyperplasia of the intestine. Non-gelatinised carbohydrates (46%) along with supplementation with 50 mgkg(-1) amylase stimulated the immune system in L. rohita juveniles. But supplementation of amylase to the gelatinised carbohydrate had no immunostimulating effect.     

Fructan Biosynthesis by Intra‐ and Extracellular Zymomonas mobilis Levansucrase after Simultaneous Production of Ethanol and Levan

The chemical composition of the Zymomonas mobilis biomass and the culture liquid after ethanol and levan synthesis were studied. The activities of intra‐ and extracellular levansucrase produced by the Z. mobilis strain 113 “S” under optimum conditions both for levan and fructooligosaccharide (FOS) synthesis were also determined. It was shown that levan production relates to the reduction of the carbohydrate and lipid content in the biomass by increasing the nucleic acid and protein content. The levan producing activity of cellular levansucrase after ethanol and levan synthesis was approximately 30–40% of the total activity in the second fermentation stage. It was established that the cell free culture liquid, containing ethanol, levan, gluconic acid and sucrose (15%) at 25 °C, did not show any additional levan synthesising activity. At optimum FOS synthesis conditions (45 °C and 70% sucrose), the cell‐free culture liquid exhibited a high FOS synthesising activity (31% from total carbohydrates), with slightly reduced biomass activity. It was concluded that as a result of the simultaneous ethanol and levan production, the remaining biomass as well as the cell‐free culture liquid could be used for FOS production.     

亚东鲑幼鱼饲料中适宜淀粉种类与水平的研究

为考察淀粉种类与水平对亚东鲑(Salmo trutta)幼鱼生长性能、饲料利用、消化酶活性、肝脏生化指标和组织学的影响, 实验采用2×3双因素设计, 选取玉米淀粉和木薯淀粉, 分别以5%、10%和15%水平添加, 共配制6种等氮等脂饲料, 饲喂初始体重为(0.50±0.03) g的亚东鲑幼鱼84d。结果表明, 随着饲料中玉米淀粉和木薯淀粉水平的提高, 增重率呈现先上升后下降的趋势, 饲料系数则先下降后上升(P<0.05), 其中10%木薯淀粉组增重率最高(518.8%), 饲料系数最低(1.32)。各组成活率、脏体比、肥满度和全鱼水分、粗蛋白质、粗脂肪和粗灰分含量均没有显著差异(P>0.05), 粗蛋白沉积率随淀粉水平的提高呈下降趋势, 其中15%水平组显著低于其他水平组(P<0.05), 而脂肪沉积率则随着淀粉水平的升高先上升后下降, 且10%木薯淀粉组显著高于玉米淀粉组(P<0.05); 淀粉种类和水平对胃蛋白酶和胃淀粉酶无显著影响(P>0.05), 15%淀粉水平组肠淀粉酶和肠蛋白酶活性显著高于其他水平组(P<0.05)。饲料中淀粉种类和水平对肝脏谷丙转氨酶、谷草转氨酶、总胆固醇和甘油三酯均无显著影响(P>0.05), 15%淀粉组的肝糖原含量显著高于其他水平组(P<0.05)。在肝脏组织学方面, 15%水平组较其余两个水平组表现出明显的细胞核移位和细胞空泡化现象。上述结果表明, 在实验条件下, 亚东鲑幼鱼饲料中淀粉的适宜添加水平为10%, 木薯淀粉的效果优于玉米淀粉。     

Persistent sub-lethal chlorine exposure augments temperature induced immunosuppression in Cyprinus carpio advanced fingerlings

Apart from increased temperature, thermal effluents discharged through cooling systems of nuclear power plants may often contain chlorine (used against bio-fouling), which may affect the immune status of fish. Therefore, a 28-day trial was undertaken to delineate the effect of high temperature and a persistent sub-lethal chlorine exposure on immunomodulation in Cyprinus carpio advanced fingerlings. Fish were acclimated to four different temperatures (26, 31, 33 and 36 degrees C) and maintained for 30 days in two different groups. One group was exposed to persistent chlorine (0.1mgL(-1)) and was compared with their respective temperature control groups (without chlorine exposure). Expression of heat shock proteins (hsp 70) was tested in muscle after 28 days using Western blotting. Haematological parameters (erythrocyte count, leucocyte count, haemoglobin), serum parameters (total protein, albumin, globulin, A/G ratio) and respiratory burst activity were tested to assess immuno-competence of C. carpio in response to temperature and chlorine exposure. Results indicated that hsp 70 was induced at 36 degrees C in temperature control groups but not in their respective temperatures in the presence of chlorine. Haematological parameters such as haemoglobin, erythrocyte and leucocyte counts appeared depressed in chlorine treated groups as compared to their respective temperature control groups. Serum protein and globulin were affected due to chlorine exposure at different acclimation temperatures. A decrease in NBT activity was recorded in chlorine treated groups as compared to their respective temperature control groups. Overall results indicate that increasing acclimation temperatures alters the immune status of C. carpio advanced fingerlings and persistent sub-lethal exposure to chlorine augments this temperature induced immunosuppression.     

大黄蒽醌提取物对饲养建鲤生长的影响

将750尾建鲤(Cyprinus carpio var.jian)随机分成5组。一组为对照组,投喂基础日粮。另外4组为实验组,投喂的基础日粮中分别添加0.5%、1.0%、2.0%、4.0%大黄蒽醌提取物。连续投喂70d后,测定鱼的生长、免疫相关因子、肠道菌数量及肉质等。结果表明,与对照组相比,添加大黄蒽醌提取物提高了鱼体增重率、饲料转化效率、溶菌酶活性、一氧化氮浓度、超氧化物歧化酶活性,促进了肠道有益菌增加,抑制有害菌生长,降低了丙二醛含量及鱼体死亡率,但是与大黄蒽醌提取物的添加水平不成线性关系;其中1.0%实验组肝胰脏溶菌酶与超氧化物歧化酶活性最高,血清丙二醛含量最低;2.0%实验组增重率、血清一氧化氮浓度与超氧化物歧化酶活性、肝胰脏一氧化氮浓度、肠道乳酸杆菌数量最高;添加1.0%~2.0%大黄蒽醌提取物显著提高了肌肉粗脂肪含量。因此,添加1.0%~2.0%大黄蒽醌提取物能改善肠道的微生态平衡,提高机体免疫机能,改善肉质,促进鱼体生长。     

Production of Levansucrase from Bacillus subtilis NRC 33a and Enzymic Synthesis of Levan and Fructo-Oligosaccharides

Bacillus subtilis NRC33a was able to produce both inducible and constitutive extracellular levansucrase, respectively, using sucrose and glucose as carbon source. The optimal production of the levansucrase was at 30°C. The effect of different nitrogen sources showed that baker’s yeast with 2% concentration gave the highest levansucrase activity. Addition of 0.15 g/L MgSO₄ was the most favorable for levansucrase production. The enzymic synthesis of levan was studied using 60% acetone fraction. The results indicated that high enzyme concentrations produced increasing amounts of levan, and hence conversion of fructose to levan reached 84% using 1000 μg/ml enzyme protein. Sucrose concentration was the most effective factor controlling the molecular weight of the synthesized levan. The conversion of fructose to levan was maximal at 30°C. The time of reaction clearly affected the conversion of fructose to levan, which reached its maximum productivity at 18 hours (92%). Identification of levan indicated that fructose was the building unit of levan.     

邻苯二甲酸二乙基己酯对鲤非特异性免疫的影响及遗传毒性

以水和吐温-80为对照,用5、20、80、160 mg/L的邻苯二甲酸二乙基己酯（DEHP）对鲤染毒20d,研究了DEHP对鲤非特异性免疫功能的影响及遗传毒性。结果表明: 吐温-80组与水对照组相比除红细胞总核异常率显著升高外,所测定的各项指标差异均不显著。80、160 mg/L组白细胞吞噬活力、吞噬指数,血清抗菌活力,溶菌酶活性均显著低于水对照组和吐温-80组（P0.05或P0.01）,且20 mg/L组白细胞吞噬活力、吞噬指数显著低于水对照组。与吐温-80组相比,160 mg/L组血清C3含量显著降低,5、20、80 mg/L组C3含量,5、20、80、160 mg/L组C4含量则无显著性差异。20、80、160 mg/L组C3含量,160 mg/L组C4含量显著低于水对照组（P0.05或P0.01）。160 mg/L组红细胞微核率显著高于吐温-80组,80、160 mg/L组红细胞微核率显著高于水对照组。在DEHP实验浓度范围内,红细胞核异常率、总核异常率,肝细胞DPC系数均显著高于水对照组和吐温-80组。一定浓度的DEHP对鲤具有免疫毒性和遗传毒性。       

Molasses and microbial inoculants improve fermentability and silage quality of cotton waste-based spent mushroom substrate

A small-silo study was conducted to develop an effective ensiling storage method for the use of cotton waste-based spent mushroom substrate (SMS) as an animal feed. The SMS was ensiled with 5% molasses (DM basis), 0.5% (v/w) lactic acid bacteria (LAB, Lactobacillus plantarum) inoculant or 0.5% (v/w) yeast (Saccharomyces cerevisiae) inoculant. The treatments included 100% SMS (control), 95% SMS+5% molasses (T1), 95% SMS+5% molasses+0.5% LAB (T2) and 95% SMS+5% molasses+5% LAB+0.5% yeast (T3). The treatments were ensiled for 10. Change in chemical compositions was little (P>0.05) according to the ensiling process and treatments. Compared with those before ensiling, 100% SMS (control) after ensiling showed unstable fermentative properties with high pH (5.2) and little lactic acid production. Compared with the ensiled control, treatments (T1, T2 and T3) resulted in decreased pH, 18-20 times higher concentrations of lactic acid, and greater populations of total bacteria (P<0.07), LAB and yeast (P<0.07). The addition of 5% molasses, 0.5% LAB and 0.5% yeast (T3) to the SMS resulted in the lowest pH (4.25) and the greatest microbial populations. Treatment T3 was selected for a large scale silo study which was ensiled for 10, 20 and 30 d. As in the small-silo study, the T3 treatment showed favorable fermentative and microbial parameters, compared with the control, by decreasing pH and increasing lactic acid concentrations, LAB and yeast populations. The minimum ensiling period was 20 d, when pH was reasonably low and LAB and yeast populations were greatest. In conclusion, molasses and microbial inoculation improved silage quality of SMS.     

Production of levan using recombinant levansucrase immobilized on hydroxyapatite

Levansucrase of Zymomonas mobilis was immobilized onto the surface of hydroxyapatite by ionic binding. Optimum conditions for the immobilization were: pH 6.0, 4 h of immobilization reaction time, and 20 U of enzyme/g of matrix. The enzymatic and biochemical properties of the immobilized enzyme were similar to those of the native enzyme, especially towards the effect of salts and detergents. The immobilized enzyme showed sucrose hydrolysis activity higher as that of the native enzyme, but levan formation activity was 70% of the native enzyme. HPLC analysis of levan produced by immobilized enzyme showed the presence of two different types of levan: high-molecular-weight levan and low-molecular-weight levan. The proportion of low-molecular-weight levan to total levan produced by the immobilized enzyme was much higher than that with the native enzyme, indicating that immobilized levansucrase could be applied to produce low-molecular-weight levan. Immobilized levansucrase retained 65% of the original activity after 6 times of repeated uses and 67% of the initial activity after 40 d when stored at 4 °C.     

Effect of body temperature during exercise on skeletal muscle cytochrome c oxidase content.

This study determined the role of body temperature during exercise on cytochrome-c oxidase (CytOx) activity, a marker of mitochondrial content, and mitochondrial heat shock protein 70 (mtHSP70), which is required for import of nuclear-coded preproteins. Male, 10-wk-old, Sprague-Dawley rats exercised identically for 9 wk in ambient temperatures of 23 degrees C (n = 10), 8 degrees C with wetted fur (n = 8), and 4 degrees C with wetted fur and fan (n = 7). These conditions maintained exercising core temperature (T(c)) at 40.4, 39.2, or 38.0 degrees C (resting temperature), respectively. During weeks 3-9, exercisers ran 5 days/wk up a 6% grade at 20 m/min for 60 min. Animals were housed at 23 degrees C. Gastrocnemius CytOx activity in T(c)=38.0 degrees C (83.5 +/- 5.5 microatoms O x min(-1) x g wet wt(-1)) was greater than all other groups (P < 0.05), exceeding sedentary (n = 7) by 73.2%. T(c) of 40.4 and 39.2 degrees C also were higher than sedentary by 22.4 and 37.4%, respectively (P < 0.05). Quantification of CytOx content verified that the increased activity was due to an increase in protein content. In extensor digitorum longus, a nonactive muscle, CytOx was not elevated in T(c) = 38.0 degrees C. mtHSP70 was significantly elevated in gastrocnemius of T(c) = 38.0 degrees C compared with sedentary (P < 0.05) but was not elevated in extensor digitorum longus (P > 0.05). The data indicate that decreasing exercise T(c) may enhance mitochondrial biogenesis and that mtHSP70 expression is not dependent on temperature.     

不同培肥措施对红壤茶园土壤微生物量碳的影响

研究了经过4年不同培肥措施后红壤茶园土壤微生物量碳变化.结果表明:稻草覆盖后不同比例有机无机肥配施、间作三叶草以及全施化肥处理对土壤微生物量碳均有明显提高;全年土壤微生物量碳年变化都呈现"低-高-低-高"的趋势,且在不同时期对微生物量碳的影响不同;与对照(CK)相比,稻草覆盖 100%有机肥(T1)、稻草覆盖 75%有机肥 25%化肥(T2)、稻草覆盖 50%有机肥 50%化肥(T3)、稻草覆盖 25%有机肥 75%化肥(T4)、100%化肥(T5)和间作三叶草 不施肥(T6)土壤微生物量碳全年平均值分别高出17.05%、32.38%、32.05%、24.30%、26.23%和24.63%,且差异均达到显著水平(P＜0.05);土壤微生物量碳与活性有机质、土壤全氮、微生物量氮、微生物量磷呈显著正相关,与速效氮、土壤全磷、土壤全钾、土壤含水量之间关系不显著;与单施化肥和全量投入有机物料相比,有机物和化肥配合施用更有利于提高土壤肥力.