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1.
Wei Cui Hengmin Cui Xi Peng Jing Fang Zhicai Zuo Xiaodong Liu Bangyuan Wu 《Biological trace element research》2011,143(1):251-260
The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on immune function by determining
the morphological changes and cell cycle of bursa of Fabricius, and the serum Ig contents. A total of 420 one-day-old avian
broilers were divided into six groups and fed on a corn–soybean basal diet as control diet, or the same diet amended to contain
5, 15, 30, 45, and 60 ppm vanadium supplied as ammonium metavanadate. When compared with that of control group, the relative
weight of bursa was significantly increased in the 15 ppm group from 14 to 35 days of age and increased in the 5 ppm group
at 42 days of age, and significantly decreased in the 60 ppm group from 14 to 42 days of age and decreased in 30 and 45 ppm
groups from 35 to 42 days of age. Pathological lesions progressed as the dietary vanadium increased. The gross lesions of
bursa showed obvious atrophy with decreased volume and pale color in 45 and 60 ppm groups. Histopathologically, widened cortex
and increased number of lymphocytes appeared in 5 and 15 ppm groups, and reduced lymphocytes and connective tissue hyperplasia
appeared in 45 and 60 ppm groups. The bursal cells in static phase (G0/G1) were decreased, and those in the mitotic phase (G2 + M) and the proliferating index (PI) were increased in 5 and 15 ppm groups. However, bursal cells in the G0/G1 phase were increased, and those in G2 + M phase, synthesis phase (S) and the PI were decreased in 45 and 60 ppm groups. Also, the serum IgG and IgA contents were
increased in 5 and 15 ppm groups, and the serum IgG, IgA, and IgM contents were decreased in 45 and 60 ppm groups. These results
suggested that dietary excess vanadium (45 and 60 ppm) could inhibit growth of bursa of Fabricius and impair humoral immunity
in chicken. 相似文献
2.
Xi Peng Hengmin Cui Junliang Deng Zhicai Zuo Weiming Lai 《Biological trace element research》2011,140(1):66-72
The purpose of this 42-day study was to investigate the effects of excess dietary selenium on immune function by determining
morphological changes of spleen and cell cycle of splenocyte. Three hundred 1-day-old avian broilers were fed on a basic diet
(0.2 mg/kg selenium) or the same diet amended to contain 1, 5, 10, and 15 mg/kg selenium (Se) supplied as sodium selenite
(n = 60/group). Anatomically, the spleens were shrinked in volume with pallecent color. Histopathologically, lymphopenia in
splenic nodules and periarterial lymphatic sheaths and congestion of the red pulp were observed in 5, 10, and 15 mg/kg Se
group. By flow cytometry method, the percentage of G0/G1 phase splenocytes was significantly increased, whereas the percentages of S phase and G2+M phase splenocytes and the proliferation index were markedly decreased in 5, 10, and 15 mg/kg Se groups when compared with
those of 0.2 mg/kg group. The results confirmed that excess dietary Se as sodium selenite in the range of 5∼15 mg/kg caused
growth retardation of spleen by cell cycle blockage in young chickens. 相似文献
3.
The purpose of this study was to examine oxidative stress induced by dietary vanadium in the mucosa of different parts of
intestine including duodenum, jejunum, ileum, and cecal tonsil. A total of 420 1-day-old avian broilers were divided into
six groups and fed on a corn–soybean basal diet as control diet or the same basal diet supplemented with 5, 15, 30, 45, and
60 mg/kg vanadium as ammonium metavanadate. During the experimental period of 42 days, oxidative stress parameters were determined
for both control and experimental groups. The results showed that malondialdehyde content was significantly higher (p < 0.05 or p < 0.01) in 30, 45, and 60 mg/kg groups than in control group. In contrast, the activities of superoxide dismutase, catalase,
and glutathione peroxidase, and ability to inhibit hydroxyl radical, and glutathione hormone content were significantly decreased
(p < 0.05 or p < 0.01) mainly in 45 and 60 mg/kg groups in comparison with those of control group. However, the abovementioned oxidative
stress parameters were not significantly changed (p > 0.05) in 5 and 15 mg/kg groups. It was concluded that dietary vanadium in excess of 30 mg/kg could cause obvious oxidative
stress in the intestinal mucosa, which could impact the antioxidant function of intestinal tract in broilers. 相似文献
4.
The purpose of this 42-day study was to investigate the apoptosis in the bursa of Fabricius induced by different levels of
dietary vanadium. A total of 420 1-day-old avian broilers were divided into 6 groups in which there were 7 replicates in each
group and 10 broilers in each replicate and fed on a corn–soybean basal diet as control diet (vanadium 0.073 mg/kg) or the
same diet amended to contain 5, 15, 30, 45, and 60 mg/kg vanadium supplied as ammonium metavanadate (NH4VO3). Ultrastructurally, mitochondrial injury and increased numbers of apoptotic cells with condensed nuclei were observed in
the 30, 45, and 60 mg/kg groups. As measured by flow cytometry, the percentages of apoptotic lymphocytes were significantly
increased in the 15-, 30-, 45-, and 60-mg/kg groups when compared with those of control group. Meanwhile, the terminal deoxynucleotidyl
transferase 2′-deoxyuridine 5′-triphosphate nick end-labeling assay showed that there were increased numbers of apoptotic
cells in the 30-, 45-, and 60-mg/kg groups. Immunohistochemical tests showed increased numbers of positive cells under Bax
and caspase-3 protein detection and decreased Bcl-2 protein in the 15-, 30-, 45-, and 60-mg/kg groups. The vanadium content
of the bursa was found to be significantly increased in the 30-, 45-, and 60-mg/kg groups. These results suggested that dietary
vanadium in excess of 15 mg/kg could cause lymphocyte apoptosis in the bursa of Fabricius and impact humoral immunity in broilers.
Lymphocyte apoptosis in the bursa induced by high levels of dietary vanadium is associated with mitochondrial injury and changes
in levels of apoptogenic proteins, such as Bcl-2, Bax, and caspase-3. 相似文献
5.
The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on immune function by determining
changes of the subsets and proliferation function of splenic T cells. Four hundred twenty 1-day-old avian broilers were divided
into six groups and fed on a corn–soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and
60 ppm of vanadium supplied as ammonium metavanadate. When compared with those of the control group, the percentage of CD3+, CD3+CD4+, and CD3+CD8+ of splenic T cells were decreased in the 45 and 60 ppm groups; however, the percentage of CD3+ and CD3+CD4+ were increased in the 5 ppm group, and the CD4+/CD8+ ratios were raised in the 5 and 15 ppm groups at 14 days of age. Meanwhile, the proliferation of splenic T cells were depressed
in the 45 and 60 ppm groups but raised in the 5 and 15 ppm groups. Also, the serum interleukin-2 (IL-2) and interleukin-6
(IL-6) contents were decreased in the 45 and 60 ppm groups and increased in the 5 ppm group. It was concluded that dietary
vanadium in excess of 30 ppm changed the percentages of splenic T cell subsets and inhibited the proliferation of splenic
T cells and reduced the serum IL-2 and IL-6 contents. The cellular immune function was finally impaired in broilers. 相似文献
6.
To investigate the influence of selenium on body weights and the immune organ indexes in ducklings administrated with aflatoxin
B1 (AFB1), 90 7-day-old ducklings were randomly divided into three groups (groups I–III). Group I was used as a blank control. Group
II was administered with AFB1 (0.1 mg/kg body weight). Group III was administered with AFB1 (0.1 mg/kg body weight) plus sodium selenite (1 mg/kg body weight). All treatments were given once daily for 21 days. It
showed that the ducklings’ bursa of fabricius, thymus indexes, and body weights in group II significantly decreased when compared
with group I (P < 0.01). Furthermore, the spleen indexes significantly decreased (P < 0.01). However, the ducklings’ bursa of fabricius and thymus indexes, body weights in group III ducklings significantly
increased when compared with group II (P < 0.01). In addition, the spleen indexes significantly decreased (P < 0.01). These results revealed that AFB1 significantly affect ducklings’ growth and immune organs development. However, selenium significantly ameliorated the negative
effects induced by AFB1. 相似文献
7.
Liu J Cui H Liu X Peng X Deng J Zuo Z Cui W Deng Y Wang K 《Biological trace element research》2012,145(2):189-200
The purpose of this study was to investigate the renal and hepatic oxidative damage and toxicity caused by dietary high vanadium
in broilers. A total of 420 one-day-old avian broilers were divided into six groups and fed on a corn–soybean basal diet as
control diet (vanadium 0.073 mg/kg), and five high vanadium diets (vanadium 5 mg/kg, high vanadium group I; 15 mg/kg, high
vanadium group II; 30 mg/kg, high vanadium group III; 45 mg/kg, high vanadium group IV; and 60 mg/kg, high vanadium group
V) throughout the experimental period of 42 days. The results showed that the renal and hepatic superoxide dismutase (SOD)
and glutathione peroxidase (GSH-Px) activities, ability to inhibit hydroxy radical, and malondialdehyde (MDA), glutathione,
and vanadium contents were not significantly changed in high vanadium group I and II when compared with those of the control
groups. However, the SOD and GSH-Px activities, ability to inhibit hydroxy radical, and GSH content were significantly decreased,
and the MDA and vanadium contents were markedly increased in high vanadium groups III, IV, and V. At the same time, the lesions
were also observed in the kidney and liver of high vanadium groups III, IV, and V. The renal tubular epithelial cells showed
granular degeneration and vacuolar degeneration, and hepatocytes showed granular degeneration, vacuolar degeneration, and
fatty degeneration. It was concluded that dietary vanadium in the range of 30–60 mg/kg could cause oxidative damage and vanadium
accumulation, which induced renal and hepatic toxicity and lesions. The renal and hepatic function was finally impaired in
boilers. 相似文献
8.
The objective of this study was to clarify the effects of dietary vanadium on cell cycle and apoptosis of liver in broilers. Four hundred and twenty one-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60?mg/kg vanadium supplied as ammonium metavanadate for 42?days. As tested by flow cytometry, hepatocytes in G (0)/G (1) phase were significantly increased in number in 45 and 60?mg/kg groups, and hepatocytes in S, G (2)?+?M phases in 45 and 60?mg/kg groups and the proliferation index of hepatocytes in 30, 45, and 60?mg/kg were markedly decreased when compared with those of control group. At the same time, the percentage of hepatocyte apoptosis was markedly increased in both 45 and 60?mg/kg groups. The results showed that dietary vanadium in the range of 45?~?60?mg/kg caused cell cycle arrest and apoptosis of hepatocytes in broilers. 相似文献
9.
Xi Peng Yun Cui Wei Cui Junliang Deng Hengmin Cui Fan Yang 《Biological trace element research》2011,139(1):32-40
The purpose of this 42-day study was to investigate the effects of low selenium (Se) on immune function by determining cell
cycle and apoptosis of bursa of Fabricius. One hundred twenty 1-day-old avian broilers were randomly assigned to two groups
of 60 each and were fed on a low Se diet (0.0342 mg/kg Se) or a control diet (0.2 mg/kg Se), respectively. The relative weight
of bursa was significantly decreased in low Se group from 28 days of age in time-dependent manner when compared with that
of control group. Cell cycle analysis by flow cytometry showed that low Se caused an increase in G0G1 phase cells that corresponded to a decrease in S phase cells in bursa of Fabricius. Ultrastructurally, mitochondria injury
and increased apoptotic cells with condensed nuclei were observed. Low Se increased the percentage of Annexin V-positive cells,
as measured by flow cytometry, in comparison with that of control group. These data suggested that low Se diet restrained
the development of bursa of Fabricius by cell cycle arrest and apoptosis. 相似文献
10.
Deng Y Cui H Peng X Fang J Wang K Cui W Liu X 《Biological trace element research》2011,144(1-3):647-656
The purpose of this 42-day study was to investigate the effects of dietary excess vanadium on intestinal immune function by histopathological observation of cecal tonsil and changes of the cecal tonsil T cell subsets by method of flow cytometry. Four hundred twenty 1-day-old avian broilers were divided into six groups and fed on a corn-soybean basal diet as control diet or the same diet amended to contain 5, 15, 30, 45, and 60 mg/kg vanadium supplied as ammonium metavanadate. In comparison with those of control group, lymphocytes in the lymphatic nodule of cecal tonsil were apparently decreased in 45 and 60 mg/kg groups. The percentage of CD(3)(+) T cells was decreased (p?0.05) in 45 mg/kg group at 28 and 42 days of age and significantly decreased (p?0.01) in 60 mg/kg group at 28 and 42 days of age. The percentages of CD(3)(+)CD(4)(+) and CD(3)(+)CD(8)(+) T cells were markedly decreased (p?0.05 or p?0.01) in 60 mg/kg group from 14 to 28 days of age and were decreased (p?0.05) in 45 mg/kg group at 28 and 42 days of age. However, changes of the CD(4)(+)/CD(8)(+) ratio were not significant. Meanwhile, the cecal tonsil interleukin-2 (IL-2) contents were decreased (p?0.05 or p?0.01) in 45 and 60 mg/kg groups from 14 to 42 days of age. It was concluded that dietary vanadium in excess of 30 mg/kg reduced the percentages of cecal tonsil T cells subsets and IL-2 contents, and caused cecal tonsil lesions, which impaired cecal tonsil function and impacted the local mucosal immune function of the intestines in broilers. 相似文献
11.
Effects of Zinc Glycine Chelate on Oxidative Stress,Contents of Trace Elements,and Intestinal Morphology in Broilers 总被引:1,自引:0,他引:1
Wenqiang Ma Haihua Niu Jiang Feng Yong Wang Jie Feng 《Biological trace element research》2011,142(3):546-556
Three hundred and sixty healthy Ross × Ross 1-day-old broilers were used to study the effects of zinc glycine chelate (Zn-Gly)
on oxidative stress, contents of trace elements, and intestinal morphology. All broilers were randomly assigned to six treatment
groups, which replicates three times. Diets were as follows: (1) control (containing 29.3 mg zinc (Zn)/kg basic diet (0–21 days)
and 27.8 mg Zn/kg (22–42 days)); (2) basic diet plus 30 mg Zn/kg from Zn-Gly; (3) basic diet plus 60 mg Zn/kg from Zn-Gly;
(4) basic diet plus 90 mg Zn/kg from Zn-Gly; (5) basic diet plus 120 mg Zn/kg from Zn-Gly; and (6) positive control, basic
diet plus 120 mg Zn/kg from zinc sulfate (ZnSO4). The results showed that the addition of 90 or 120 mg/kg Zn-Gly led to an improvement of activity of Cu/Zn superoxide dismutase
and glutathione peroxidase and a reduction of malondialdehyde content in livers at 21 and 42 days. With 90 mg/kg Zn-Gly, the
content of sera zinc increased by 17.55% (P < 0.05) in 21-day broilers and 10.77% (P > 0.05) in 42-day broilers compared with that of the control. Adding 120 mg/kg Zn-Gly or ZnSO4 to broilers' diets greatly enhanced the content of zinc in feces at 21 days (P < 0.05) and at 42 days (P < 0.05). For 42-day chickens, increased villus height and decreased crypt depth of the jejunum could be observed in the second
growth stage of broilers fed with 90 mg/kg Zn-Gly. Also, intestinal wall thickness decreased (P < 0.05). In addition, adding 90 mg/kg Zn-Gly to the diet markedly elevated villus length of duodenum and decreased crypt
depth of ileum (P < 0.05) in 42-day broilers. 相似文献
12.
To compare the effect of IV magnesium with other antihypertensives in emergency department (ED) patients with hypertension.
ED patients with a systolic BP > 135 mmHg or diastolic BP > 85 were approached for entry into the study. Those granting consent
were randomly placed into one of three treatment groups: (1) 1.5 gm IV MgSO4 (n = 42), (2) a parenteral or oral antihypertensive agent (n = 41), (3) both IV MgSO4 and an antihypertensive agent (n = 44). Systolic and diastolic blood pressures were measured at entry into the study and at 15, 30, 45, and 60 min after magnesium
or other antihypertensive medications were given. The main outcome measure was blood pressure at 60 min, and results were
compared using one-way analysis of variance with the post hoc Tukey HSD test. Compared to systolic and diastolic blood pressures
at time 0, both were lower at 15, 30, 45, and 60 min in all groups (p < 0.05). No significant difference in systolic or diastolic BP at any time point was observed when response to treatment
was compared between the three groups. Intravenous MgSO4 is as effective as antihypertensives at lowering BP in emergency department patients. 相似文献
13.
Forty-eight 2-year-old Liaoning Cashmere goats (body weight = 38.0 ± 2.94 kg) were used to investigate the effects of dietary
iodine (I) and selenium (Se) supplementation on nutrient digestibility, serum thyroid hormones, and antioxidant status during
the cashmere telogen period to learn more about the effects of dietary I and Se on nutrition or health status of Cashmere
goats. The goats were equally divided into six groups of eight animals each that were treated with 0, 2, or 4 mg of supplemental
I/kg dry matter (DM) and 0 or 1 mg of supplemental Se/kg DM in a 2 × 3 factorial arrangement of treatments. The six treatments
were I0Se0, I2Se0, I4Se0, I0Se1, I2Se1, and I4Se1. The concentrations of I and Se in the basal diet were 0.67 and 0.09 mg/kg DM, respectively. The study started in March and
proceeded for 45 days. Supplemental I or Se alone had no effect on nutrient digestibility and nitrogen metabolism. However,
the interaction between I and Se was significant regarding the digestibility of acid detergent fiber (ADF; P < 0.05), and compared with group I4Se1, the digestibility of ADF was significantly increased in group I4Se0 (P < 0.05). Selenium supplementation did not affect serum triiodothyronine (T3) or thyroxine (T4) concentrations. However, the concentration of serum T4 but not that of T3 was significantly increased with I supplementation (P < 0.05). In addition, serum superoxide dismutase (SOD) activity was not affected (P > 0.05), but serum glutathione peroxidase (GSH-Px) activity was significantly decreased by I supplementation (P < 0.05). The antioxidant status was improved by Se supplementation, and the activities of SOD and GSH-Px were significantly
increased (P < 0.05). 相似文献
14.
J. Langfort R. Zarzeczny W. Pilis K. Nazar H. Kaciuba-Ucitko 《European journal of applied physiology and occupational physiology》1997,76(2):128-133
The aim of this study was to find out whether a low-carbohydrate diet (L-CHO) affects: (1) the capacity for all-out anaerobic
exercise, and (2) hormonal and metabolic responses to this type of exercise. To this purpose, eight healthy subjects underwent
a 30-s bicycle Wingate test preceded by either 3 days of a controlled mixed diet (130 kJ/kg of body mass daily, 50% carbohydrate,
30% fat, 20% protein) or 3 days of an isoenergetic L-CHO diet (up to 5% carbohydrate, 50% fat, 45% protein) in a randomized
order. Before and during 1 h after the exercise venous blood samples were taken for measurement of blood lactate (LA), β-hydroxybutyrate
(β-HB), glucose, adrenaline (A), noradrenaline (NA) and insulin levels. Oxygen consumption (V˙O2) was also determined. It was found that the L-CHO diet diminished the mean power output during the 30-s exercise bout [533
(7) W vs 581 (7) W, P < 0.05] without changing the maximal power attained during the first or second 5-s interval of the exercise. In comparison
with the data obtained after the consumption of a mixed diet, after the consumption of a L-CHO diet resting plasma concentrations
of β-HB [2.38 (0.18) vs 0.23 (0.01) mmol · l−1, P < 0.001] and NA [4.81 (0.68) vs 2.2 (0.31) nmol · l−1, P < 0.05] were higher, while glucose [4.6 (0.1) vs 5.7 (0.2) mmol · l−1, P < 0.05] and insulin concentrations [11.9 (0.9) vs 21.8 (1.8) mU · l−1] were lower. The 1-h post-exercise excess of V˙O2 [9.1 (0.25) vs 10.6 (0.25) l, P < 0.05], and blood LA measured 3 min after the exercise [9.5 (0.4) vs 10.6 (0.5) mmol · l−1, P < 0.05] were lower following the L-CHO treatment, whilst plasma NA and A concentrations reached higher values [2.24 (0.40) vs
1.21 (0.13) nmol · l−1 and 14.30 (1.41) vs 8.20 (1.31) nmol · l−1, P < 0.01, respectively]. In subjects on the L-CHO diet, the plasma β-HB concentration decreased quickly after exercise, attaining
≈30% of the pre-exercise value within 60 min, while insulin and glucose levels were elevated. The main conclusions of this
study are: (1) a L-CHO diet is detrimental to anaerobic work capacity, possibly because of a reduced muscle glycogen store
and decreased rate of glycolysis; (2) reduced carbohydrate intake for 3 days enhances activity of the sympathoadrenal system
at rest and after exercise.
Accepted: 31 January 1997 相似文献
15.
Xi Peng Yun Cui Wei Cui Junliang Deng Hengmin Cui 《Biological trace element research》2009,131(1):33-42
Selenium is an essential trace element possessing immune-stimulatory properties. The purpose of this 42-day study was to investigate
the effects of excess dietary sodium selenite on immune function by determining morphological changes and apoptosis of bursa
of Fabricius. Three hundred 1-day-old Avian broilers were fed on a basic diet (0.2 ppm selenium) or the same diet amended
to contain 1, 5, 10, and 15 ppm selenium supplied as sodium selenite (n = 60/group). Relative weight of bursa was significantly decreased in the 1, 5, 10, and 15 ppm groups at 28 days of age, when
compared with that of 0.2 ppm group. Pathological lesions were progressed with the dietary Se level increased. The gross lesions
of bursa involved obvious atrophy with decreased volume and pale color. Histopathologically, decreased number of lymphocytes
and loosely packed lymphocytes appeared in the medulla and cortex in the follicles. Ultrastructurally, mitochondria injury
and increased apoptotic cells with condensed nuclei were observed. In comparison to that of control group, excess Se (5, 10,
and 15 ppm) intake increased the percentage of Annexin V positive cells, as measured by flow cytometry. Terminal deoxynucleotidyl
transferase 2′-deoxyuridine 5′-triphosphate nick end-labeling assay showed that there were increased frequencies of apoptotic
cells in 10 and 15 ppm selenium groups. These data suggest that Se supplementation with sodium selenite should be carefully
evaluated as excess selenium (more than 5 ppm) intake could cause profound immunologic inhibition. 相似文献
16.
Tascilar ME Ozgen IT Abaci A Serdar M Aykut O 《Biological trace element research》2011,143(1):188-195
The quality of the diet of obese children is poor. Eating habits may alter micronutrient status in obese patients. In this
study, we determined the serum levels of selenium, zinc, vanadium, molybdenum, iron, copper, beryllium, boron, chromium, manganese,
cobalt, silver, barium, aluminum, nickel, cadmium, mercury, and lead in obese Turkish children. Thirty-four obese and 33 healthy
control subjects were enrolled in the study. Serum vanadium and cobalt levels of obese children were significantly lower than
those of the control group (0.244 ± 0.0179 vs. 0.261 ± 0.012 μg/l, p < 0.001, and 0.14 ± 0.13 vs. 0.24 ± 0.15 μg/l, p = 0.011, respectively). There was no significant difference between groups regarding the other serum trace element levels.
In conclusion, there may be alterations in the serum levels of trace elements in obese children and these alterations may
have a role in the pathogenesis of obesity. 相似文献
17.
In the present paper we employ a series of dicationized (K+& C+; C = H, Li, Na, or K) hexapeptide (G6C+K+
x, x = 1, 2, … or 5) complexes in gas phase (GP) and aqueous phase (AP) as models to mimic the key characteristics of the real
biosystems. An interesting phenomenon is observed that the binding properties of K+
x to G6C+ species change in the two phases, i.e., those positive binding energies in the GP become negative ones in the AP. Then we
probe the origin of property change of the binding energies in the two different phases and associate these changes with some
biological phenomena. 相似文献
18.
S. Sánchez V. Bravo E. Castro A. J. Moya F. Camacho 《Applied microbiology and biotechnology》1998,50(5):608-611
We have analysed the influence of the initial pH of the medium and the quantity of aeration provided during the batch fermentation
of solutions of d-xylose by the yeast Hansenula polymorpha (34438 ATCC). The initial pH was altered between 3.5 and 6.5 whilst aeration varied between 0.0 and 0.3 vvm. The temperature
was kept at 30 °C during all the experiments. Hansenula polymorpha is known to produce high quantities of xylitol and low quantities of ethanol. The most favourable conditions for the growth
of xylitol turned out to be: an initial pH of between 4.5 and 5.5 and the aeration provided by the stirring vortex alone.
Thus, at an initial pH of 5.5, the maximum specific production rate (μm) was 0.41 h−1, the overall biomass yield (Y
x/s
G) was 0.12 g g−1, the specific d-xylose-consumption rate (q
s
) was 0.075 g g−1 h−1 (for t = 75 h), the specific xylitol-production rate (q
Xy
) was 0.31 g g−1 h−1 (for t = 30 h) and the overall yields of ethanol (Y
E/s
G) and xylitol (Y
Xy/s
G) were 0.017 and 0.61 g g−1 respectively. Both q
s
and q
Xy
decreased during the course of the experiments once the exponential growth phase had finished.
Received: 26 March 1998 / Received revision: 30 June 1998 / Accepted: 2 July 1998 相似文献
19.
The present study was carried out to determine the effects of different sources of selenium (Se; sodium selenite [Na2SeO3] or selenomethionine [Se-Met]) supplementation on egg production, egg quality, levels of malondialdehyde (MDA), and Se in
serum and egg yolk in heat-stressed Japanese quail (Coturnix coturnix japonica). The birds (n = 360; 55 days old) were randomly assigned to 12 treatment groups consisting of six replicates of five birds each in a 2 × 2 × 3
factorial arrangement of treatments (temperatures, selenium sources, selenium levels). Birds were kept in wire cages in a
temperature-controlled room at either 22 (thermoneutral) or 34°C (heat stress) for 8 h/day (09:00–17:00; till the end of study)
and fed a basal (control) diet or the basal diet supplemented with either 0.15 or 0.30 mg of Na2SeO3 or selenomethionine/kg of diet. Heat exposure decreased live weight, feed intake, feed efficiency, egg production, and egg
quality when basal diet was fed (P < 0.0001). A linear increase in feed intake (P = 0.001) and body weight (P = 0.001), egg production (P = 0.001), and improvement in feed efficiency (P = 0.001) and egg quality (P = 0.001) were found in Se-supplemented quail reared under heat stress conditions. Serum, egg white, and egg yolk Se (P ≤ 0.001) concentrations increased linearly, whereas serum, liver, and egg yolk MDA concentrations decreased linearly (P = 0.001) as dietary Na2SeO3 or Se-Met supplementation increased. An interaction between dietary Se sources, temperature, and levels of supplementation
(P ≤ 0.05) for these parameters was detected. Supplementation with Se improved egg production, egg quality, and antioxidant
status of birds, and the effects of Se-Met were relatively greater than Na2SeO3 in heat-stressed quail. Results of the present study suggest that supplementation with Se-Met can be considered to be more
protective than Na2SeO3 by reducing the negative effects of oxidative stress induced by heat stress in quail. 相似文献
20.
Fritz Geiser G. J. Kenagy John C. Wingfield 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(6):416-422
Dietary cholesterol can affect both body lipid composition and steroid hormone concentration. We investigated whether a diet
rich in cholesterol influences torpor patterns of hibernating chipmunks (Tamias amoenus) and, if so, whether these changes are better explained by diet-induced changes in body lipid composition or the concentration
of testosterone, which at high levels inhibits torpor. Two groups of chipmunks were maintained either on a cholesterol diet
(rodent chow containing 10% cholesterol) or a control diet (rodent chow) during pre-hibernation fattening and throughout the
hibernation season. Torpid chipmunks on the cholesterol diet had significantly lower minimum body temperatures (−0.2 ± 0.2
vs +0.6 ± 0.2 °C), lower metabolic rates (0.029 ± 0.002 ml O2 g−1h−1 vs 0.035 ± 0.001 ml O2 g−1h−1), and longer torpor bouts at −1 °C (6.8 ± 0.5 vs 4.1 ± 1.0 days) than chipmunks on the control diet. Dietary cholesterol
resulted in a significant increase in blood plasma cholesterol (sevenfold), liver cholesterol content (6.9-fold) and liver
triglyceride content (3.5-fold) in comparison to controls. In contrast, dietary cholesterol had no detectable effect on the
concentration of plasma testosterone, which was very low in both groups. Since torpor was deeper and longer in animals on
the cholesterol diet our study suggests that torpor patterns of chipmunks were either directly affected by the dietary cholesterol
or via changes in body lipid composition.
Accepted: 22 January 1997 相似文献