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1.
2.
Lactobacilli in fecal material from humans, pigs, and chickens were enumerated on lactobacillus selective agar (LBS). In all samples, higher numbers of lactobacilli were detected when plates were incubated in a system flushed with CO2 rather than in air. Much higher numbers of bacteria from human feces were detected when the LBS agar plates were incubated anaerobically in a hydrogen-carbon dioxide atmosphere (GasPak) than when incubated in CO2. The bacteria from human feces isolated on LBS agar incubated anaerobically were predominately bifidobacteria. Cultures from all three sources isolated on LBS agar incubated under CO2 were lactobacilli, including Lactobacillus acidophilus. Differences were observed in biochemical characteristics of some of the L. acidophilus isolated from all three sources. Guanine plus cytosine base ratios of deoxyribonucleic acid isolated from L. acidophilus cultures from humans were lower, in most cases, than those from pigs and chickens.  相似文献   

3.
An experiment was conducted to investigate the effects of dietary energy level on the performance and immune function of stressed broiler chickens (Gallus gallus domesticus). A total of 96 three-day-old male broiler chickens (Ross × Ross) were divided into two groups. One group received a high energy (HE) diet and the other group received a low energy (LE) diet for 7 days. At 5 days of age, the chickens from each group were further divided into two sub-groups and received one of the following two treatments for 3 days: (1) subcutaneous injection of corticosterone, twice per day (CORT group; 2 mg of CORT/kg BW in corn oil) and (2) subcutaneous injection of corn oil, twice per day (Control/Sham treatment group). At 10 days of age, samples of blood, duodenum, jejunum, and ileum were obtained. Compared with the other three groups, the LE group treated with CORT had the lowest average daily gain (ADG) and the poorest feed conversion ratio (FCR, P < 0.05). Furthermore, CORT treatment decreased the relative weight (RW) of the bursa independent of the dietary energy level, but it decreased the RW of the thymus only in the chickens fed the LE diet. By contrast, CORT administration decreased the RW of the spleen only in the chickens fed the HE diet (P < 0.05). The plasma total protein, albumin, tumor necrosis factor alpha, interleukin 2 and immunoglobulin G (IgG) levels were affected by the CORT treatment (P < 0.05); however, these factors were not significantly affected by the dietary energy level. Toll-like receptor-5 mRNA level was down-regulated by CORT injection in the duodenum and ileum (P < 0.05) and showed a trend of down-regulation in the jejunum (P=0.0846). The present study showed that CORT treatment induced immunosuppressive effects on the innate immune system of broiler chickens, which were ameliorated by consumption of higher dietary energy.  相似文献   

4.
Due to antimicrobial properties, nisin is one of the most commonly used and investigated bacteriocins for food preservation. Surprisingly, nisin has had limited use in animal feed as well as there are only few reports on its influence on microbial ecology of the gastrointestinal tract (GIT). The present study therefore aimed at investigating effects of dietary nisin on broiler chicken GIT microbial ecology and performance in comparison to salinomycin, the widely used ionophore coccidiostat. In total, 720 one-day-old male Ross 308 chicks were randomly distributed to six experimental groups. The positive control (PC) diet was supplemented with salinomycin (60 mg/kg). The nisin (NI) diets were supplemented with increasing levels (100, 300, 900 and 2700 IU nisin/g, respectively) of the bacteriocin. The negative control (NC) diet contained no additives. At slaughter (35 days of age), activity of specific bacterial enzymes (α- and β-glucosidases, α-galactosidases and β-glucuronidase) in crop, ileum and caeca were significantly higher (P<0.05) in the NC group, and nisin supplementation decreased the enzyme activities to levels observed for the PC group. A similar inhibitory influence on bacterial activity was reflected in the levels of short-chain fatty acids (SCFA) and putrefactive SCFA (PSCFA) in digesta from crop and ileum; no effect was observed in caeca. Counts of Bacteroides and Enterobacteriacae in ileum digesta were significantly (P<0.001) decreased by nisin and salinomycin, but no effects were observed on the counts of Clostridium perfringens, Lactobacillus/Enterococcus and total bacteria. Like salinomycin, nisin supplementation improved broiler growth performance in a dose-dependent manner; compared to the NC group, the body weight gain of the NI900 and NI2700 groups was improved by 4.7 and 8.7%, respectively. Our findings suggest that dietary nisin exerts a mode of action similar to salinomycin and could be considered as a dietary supplement for broiler chickens.  相似文献   

5.
The effects of administering low levels of aflatoxin B(1)-(14)C by crop intubation daily for 14 days to broiler chickens were determined. Studies on the distribution of (14)C in the blood, selected organs, tissues, and excreta were conducted. No toxic effects were observed in broiler chickens during the 14 days of the experiment. The broiler chickens excreted 90.64% of the (14)C administered. Of the (14)C retained, 11.04, 9.83, 4.30, 12.52, 31.66, and 30.63% were detected in the blood, liver, heart, gizzard, breast, and leg, respectively. Chemical assay of those samples demonstrating radioactivity revealed that 81.2% of the radioactivity in these substrates was not extractable by classical extraction procedures while approximately 10% was extractable. Treatment of aqueous extracts for conjugated steroids by treatments with beta-glucuronidase revealed that 31.5% of the (14)C detected in the aqueous extract was a liberated glucuronide conjugate of aflatoxin M(1)-(14)C.  相似文献   

6.
Fluoride can exert toxic effects on soft tissues, giving rise to a broad array of symptoms and pathological changes. The aim of this study was to investigate on erythrocytes and erythrocyte immune adherence function in broiler chickens fed with high fluorine (F) diets by measuring the total erythrocyte count (TEC), the contents of hemoglobin (Hb), packed cell volumn (PCV), erythrocyte osmotic fragility (EOF), erythrocyte C3b receptor rosette rate (E-C3bRR), and erythrocyte immune complex rosette rate (E-ICRR). A total of 280 1-day-old healthy avian broiler chickens were randomly allotted into four equal groups of 70 birds each and fed with a corn–soybean basal diet containing 22.6 mg F/kg (control group) or same basal diets supplemented with 400, 800, and 1,200 mg F/kg (high F groups I, II, and III) in the form of sodium fluoride for 42 days. Blood samples were collected for the abovementioned parameters analysis at 14, 28, and 42 days of age during the experiment. The experimental results indicated that TEC, Hb, and PCV were significantly lower (p?<?0.05 or p?<?0.01), and EOF was higher (p?<?0.05 or p?<?0.01) in the high F groups II and III than that in the control group from 14 to 42 days of age. The E-C3bRR was significantly decreased (p?<?0.01) in the three high F groups, whereas the E-ICRR was markedly increased (p?<?0.01) in the high F groups II and III from 14 to 42 days of age. It was concluded that dietary F in the range of 800 to 1, 200 mg/kg could significantly cause anemia and impair the integrity of erythrocyte membrane, the transport capacity of oxygen and carbon dioxide, and erythrocyte immune adherence function in broiler chickens.  相似文献   

7.
Bacteria from crops of 1- and 5-week-old broiler chickens fed with two brands (diets A and B) of wheat-based diets were isolated on Lactobacillus-selective medium and identified (n = 300) based on partial 16S rRNA gene sequence. The most abundant Lactobacillus species were L. reuteri (33%), L. crispatus (18.7%), and L. salivarius (13.3%). Regardless of farm and feed, L. reuteri was the most abundant species (P < 0.005) in the crops of the younger chickens. However, the amount of L. reuteri was significantly reduced in the crops of the 5-week-old chickens regardless of the feed (P = 0.016). The diversity of L. reuteri isolates was studied by fatty acid analysis, and the 94 L. reuteri isolates could be arranged into several clusters. The nisin sensitivities of the L. reuteri isolates were determined because nisin is a candidate coccidiostat. Sensitive isolates were found more frequently in younger chickens (77%) than in 5-week-old chickens (23%), whereas chickens fed with commercial feed B had a higher proportion of nisin-resistant isolates (73%) than did chickens fed with feed A (45%). Nisin-resistant strains are potential candidates for adjunct cultures for maintaining L. reuteri in its natural niche in the crop and are potential targets for genetic engineering with nisin-selectable food-grade vectors. The diversity of the L. reuteri population suggested that one should consider including several strains representing different clusters and nisin resistance phenotypes in candidate probiotic feed supplements for chickens.  相似文献   

8.
To investigate the effects of dietary manganese (Mn) supplementation on iron (Fe) metabolism, a total of 480 50-week-old hens were fed the basal diet (control, 24.35 mg Mn/kg) without Mn supplementation for 6 weeks to reduce Mn storage in the body. Hens were then randomly assigned to one of three treatments, which included the control and control added with 60 or 300 mg Mn/kg diet (M-Mn or H-Mn). Duodenum, heart, liver, and tibia were collected in hens after 12-week feeding period. No significant differences were observed in egg production, feed/egg ratio, shell breaking strength, and shell thickness among different treatments. Compared with control or M-Mn, H-Mn decreased (P?P?P?P?P?>?0.10) Fe concentration in the heart and tibia. In conjunction with reduced Fe retention, DMT1 mRNA expression decreased (P?mRNA level was higher (P?mRNA expression was lower (P?相似文献   

9.
Lactobacilli are autochthonous residents in the chicken gastrointestinal tract, where they may potentially be used as probiotics, competitive exclusion agents, or delivery vehicles. The aim of this study was to use an in vivo model to investigate the effect of diet and competing lactic acid bacteria on the colonization of inoculated Lactobacillus strains, with the goal of identifying strains which can consistently colonize or persist for an extended period of several weeks. Chicken-derived Lactobacillus strains were genetically marked with rifampin resistance and administered on day 0 to chickens fed either a normal commercial diet or a specially formulated high-protein diet. Chickens fed the high-protein diet were also coinoculated with two different mixes of additional lactic acid bacteria. Enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) was used to identify rifampin-resistant isolates recovered from chickens. Three strains, belonging to the species Lactobacillus agilis, Lactobacillus crispatus, and Lactobacillus vaginalis, were commonly reisolated from the chickens on both diets at days 21 and 42. The ability of these strains to persist was confirmed in a second chicken trial. All three strains persisted throughout the production period in the chickens fed a commercial diet, while only the L. agilis and L. vaginalis strains persisted in the chickens fed the high-protein diet. In both in vivo trials, competing lactic acid bacteria modified representation of the strains recovered, with all three stains capable of competing in the presence of one or both mixes of coinoculated strains. The in vivo model successfully identified three persistent strains that will be characterized further.The ecology of the chicken gastrointestinal tract (GIT) has been studied in depth using both culture-dependent (5, 7, 21, 40) and -independent methods (2, 3, 7, 33, 54). These studies have revealed that lactobacilli are autochthonous residents in chickens, where they predominate in the proximal GIT and are present but less abundant within the distal GIT (52). The most commonly identified Lactobacillus species are Lactobacillus crispatus, Lactobacillus reuteri, and Lactobacillus salivarius (1, 7, 15, 26, 28). A detailed understanding of the relationship between these bacteria and their host under different dietary and environmental conditions will facilitate the development of lactobacilli for various applications directed toward increasing broiler production efficiency and improving chicken health.Since the withdrawal of antimicrobial growth promoters from chicken feed in Europe, the incidence of necrotic enteritis (NE) has increased (9, 51). Consequently, there is a need to develop alternative methods for controlling the causative agent of NE, Clostridium perfringens, in the chicken GIT. Lactobacilli are excellent candidates for alternative control methods due to their autochthonous nature and dominance of the upper GIT microbiota, particularly within the small intestine where NE occurs. Their potential utility in the control of NE has been demonstrated, with several strains of Lactobacillus showing some efficacy as probiotics to decrease C. perfringens carriage within the small intestine of chickens (14, 25, 31, 37, 47). Lactobacilli are also excellent candidates as mucosal delivery vectors designed to express bioactive peptides in situ to reduce colonization by C. perfringens. The use of lactobacilli and other lactic acid bacteria (LAB) as live delivery vectors for therapeutic proteins has recently been reviewed (6, 53), but few studies have been conducted in chickens (46, 55, 56). An attenuated Salmonella enterica serovar Typhimurium delivery vector targeting C. perfringens has provided partial protection against experimental NE challenge (35, 57). Identification of Lactobacillus strains for use as delivery vectors, competitive exclusion agents, or probiotics is complicated by the difficulty in selecting truly autochthonous strains capable of reliably and consistently colonizing the chicken GIT upon subsequent inoculation.Traditionally, strain selection for in vivo applications has involved several in vitro characterization assays, including assays of aggregation, coaggregation, cell wall hydrophobicity, acid tolerance, bile salt tolerance, adhesion to epithelial cell lines, and antimicrobial activity (23, 32, 34, 44, 49). While these assays can be used to reduce the number of strains examined, they may also bias the selection of strains and could potentially overlook strains which may be competitive or have other desirable characteristics in vivo. One of the limitations of in vivo screening of lactobacilli is the need for reliable high-throughput screening techniques to identify and track persistent strains. Recently, our group reported the application of enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) to simultaneously type large numbers of Lactobacillus isolates from the chicken GIT to the species and strain level (48).The primary aim of this study was to use a new, direct, in vivo screening method to examine the ecology of inoculated Lactobacillus strains in chickens fed different diets (high protein versus commercial). A second aim of this study was to determine the ecological effect of coinoculating two different mixes of competing LAB in chickens fed a high-protein diet, which predisposes chickens to develop NE. Inoculated strains were marked with rifampin resistance (Rifr), and ERIC-PCR was used to identify strains isolated from the chickens at days 21 and 42. Three persistent strains were identified in the initial trial and selected for further characterization in a subsequent experiment, in which two strains persisted in chickens fed the high-protein diet and all three persisted in chickens fed the commercial diet. In general, competing LAB modified strain representation and, in some cases, facilitated colonization of some strains. These three persistent strains will be further characterized as potential vectors to be used in the antibiotic-free control of NE.  相似文献   

10.
Sixteen strains of Lactobacillus reuteri and 20 strains of Lactobacillus acidophilus were tested for resistance to 22 antibiotics by using commercially available sensitivity disks. Evidence suggesting linkage of these resistances to plasmids was obtained by "curing" experiments with acridine dyes and high growth temperatures. Examination of plasmid patterns of agarose gel electrophoresis provided further evidence of loss in plasmid DNA under curing conditions in some of the strains examined.  相似文献   

11.
为研究肉鸡日粮中添加树舌[Ganoderma applanatum(Pers.ex Gray.)Pat.]发酵浸膏对肉鸡盲肠道微生物菌群及短链脂肪酸的影响,选用1日龄AA肉鸡225只,随机分为5个处理组,即空白组(基础日粮)、抗生素组(基础日粮中添加5 mg/kg黄霉素)、3个剂量的GAC添加组(基础日粮中分别添加1.57,3.15,6.29 g/100 g的GAC),每个处理3组重复,每组重复15只。试验期42 d。结果表明:肉鸡21日龄时,各GAC添加组沙门氏菌显著低于空白组(P0.05);各GAC添加组乳酸杆菌显著高于空白组(P0.05);各GAC添加组盲肠乙酸、丙酸浓度显著高于空白组(P0.05);6.29%GAC添加组盲肠丁酸浓度显著高于空白组(P0.05)。肉鸡42日龄时,1.57%和6.29%GAC添加组沙门氏菌显著低于空白组(P0.05),6.29%GAC添加组效果较好;各GAC添加组乳酸杆菌显著高于空白组(P0.05)。1.57%与6.29%GAC添加组盲肠乙酸、丙酸浓度显著高于空白组(P0.05);各GAC添加组盲肠丁酸浓度显著高于空白组(P0.05)。以上结果提示,GAC在肉鸡生长过程中可以增加肠道短链脂肪酸浓度,促进肠道乳酸杆菌的增殖,抑制沙门氏菌的生长,具有改善肠道菌群的作用。  相似文献   

12.
The response of Lactobacillus acidophilus CRL 639 to cold-shock (freezing) depends on the initial growth temperature. Cells cultured at 25°C (long filaments with a value of 0.02 h–1) show a higher -galactosidase activity and develop cryotolerance, compared with cells grown at 37°C. One-dimensional proteins gel electrophoresis shows the over-expression of six proteins (22.5–105.0 kDa) and the repression of eight proteins (4.3–48.0 kDa) at 25°C. © Rapid Science Ltd. 1998  相似文献   

13.
The present study has been designed to investigate the impact of dietary iodine intake on lipid metabolism in mice, including iodine deficiency and iodine excess. Different amounts of iodine mixed in the drinking water were continuously administered to mice. The body weights and the levels of urinary iodine were measured 8 months after the treatment. Thyroid hormones in the serum were detected by chemiluminescence immunoassay. Serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol and low-density lipoprotein cholesterol (LDL-C) were determined enzymatically by automatic analyzer. Results showed that the urine iodine concentrations paralleled the amounts of iodine intakes. No statistical differences of body weights among different groups were found. The levels of thyroid hormones were dramatically decreased in iodine deficiency while no significant differences were found between iodine excess groups and normal iodine group. In iodine deficiency groups, the levels of TG, TC, and LDL were increased at varying degrees. In iodine excess groups, the levels of TG in the male mice and the levels of TC in the female mice were much lower than normal iodine group. In conclusion, dietary iodine intake may affect the metabolism of serum lipids. Hypothyroid function induced by iodine deficiency may be responsible for the changes of lipids. Higher iodine intake might benefit lipid metabolism.  相似文献   

14.
15.
Male Sprague-Dawley rats, 4 weeks (young) or 8 months (adult) of age, were fed one of three purified diets free of or containing either 0.5% cholesterol or 0.5% oxidized cholesterol (92% oxidized cholesterol) for 3 weeks. Feeding of oxidized cholesterol caused a significant reduction of food intake, body weight gain, and relative liver weight in rats of both ages. The activity of the HMG-CoA reductase and cholesterol 7α-hydroxylase of liver microsomes, the key enzymes in cholesterol synthesis and catabolism, respectively, was lowered by oxidized cholesterol compared to the diet free of cholesterol in both ages, and the difference was significantly in the adult. On the other hand, the activity of Δ6-desaturase of liver microsomes, a key enzyme in linoleic acid metabolism to arachidonic acid, was significantly increased by oxidized cholesterol in adult rats, leading to the increase in linoleic acid desaturation index [(20:3n-6 + 20:4n-6)/18:2n-6] in liver phospholipids. Oxidized cholesterol reduced the concentration of cholesterol in serum and liver. Also, the fecal excretion of acidic steroids was lower in rats fed the oxidized cholesterol diet than in those fed the cholesterol-free diet. Thus, oxidized cholesterol significantly influenced cholesterol and fatty acid metabolism in particular in adult rats.  相似文献   

16.
A real-time quantitative PCR assay targeting a 16S-23S intergenic spacer region sequence was devised to measure the sizes of populations of Lactobacillus salivarius present in ileal digesta collected from broiler chickens. This species has been associated with deconjugation of bile salts in the small bowel and reduced broiler productivity. The assay was tested as a means of monitoring the sizes of L. salivarius populations from broilers fed diets with different compositions, maintained at different stocking densities, or given the antimicrobial drugs bacitracin and monensin in the feed. Stocking densities did not influence the numbers of L. salivarius cells in the ileum. A diet containing meat and bone meal reduced the size of the L. salivarius population relative to that of chickens given the control diet, as did administration of bacitracin and monensin in the feed. These changes in the target bacterial population were associated with improved broiler weight gain.  相似文献   

17.
A 56-day feeding experiment was conducted to investigate the effects of yeast chromium (Cr, 300 μg/kg diet) and/or l-carnitine (100 mg/kg diet) on lipid metabolism and their interaction in sheep. After a 14-day adaptation period, 32 3-month-old sheep were randomly divided into four groups of eight. All sheep were fed with basal diets according to the American feeding standard of the National Research Council. At the end of the experiment, yeast Cr and/or l-carnitine supplementation significantly decreased abdominal fat mass and abdominal fat percentage, suggesting an improved mutton quality. Compared with the control group, the ratio of glucose to insulin was significantly increased, due to unchanged glucose levels and reduced insulin levels in yeast Cr and/or l-carnitine supplement groups, indicating high insulin sensitivity and well-controlled serum glucose levels. In addition, yeast chromium and/or l-carnitine induced significant decreases in serum triglyceride levels and serum total cholesterol levels, while increasing serum free fatty acid levels and high-density lipoproteincholesterol levels. The findings show that adding a yeast Cr and/or l-carnitine supplement may give better control of glucose and lipid variables.  相似文献   

18.
Lactobacilli were isolated from jejunal chyme from five fistulated beagles. Cultivable lactobacilli varied from 10(4) to 10(8) CFU/ml. Seventy-four isolates were identified by partial 16S rRNA gene sequencing and differentiated by repetitive element PCR (Rep-PCR), Lactobacillus acidophilus was dominant, and nearly 80% of 54 isolates shared the same DNA fingerprint pattern.  相似文献   

19.
A total of 91 type and reference strains of the Lactobacillus casei group and the L acidophilus group were characterized by the automated ribotyping device Riboprinter microbial characterization system. The L. casei group was divided into five (C1-C5) genotypes by ribotyping. Among them, the strain of L. casei ATCC 334 was clustered to the same genotype group as most of L. paracasei strains and L casei JCM 1134T generated a riboprint pattern that was different from the type strain of L. zeae. These results supported the designation of L. casei ATCC 334 as the neotype strain, but were not consistent with the reclassification of L. casei JCM 1134T as L. zeae. The L. acidophilus group was also divided into 14 (A1-A11, B1-B3) genotypes by ribotyping. L. acidophilus, L. amylovorus, L. crispatus and L. gallinarum generated ribotype patterns that were distinct from the patterns produced by L. gasseri and L. johnsonii. This result confirmed previous data that the L. acidophilus group divided to two major clusters. Five strains of L. acidophilus and two strains of L. gasseri were correctly reidentified by ribotyping. Most strains belonging to the L. casei group and the L. acidophilus group were discriminated at the species level by automated ribotyping. Thus this RiboPrinter system yields rapid, accurate and reproducible genetic information for the identification of many strains.  相似文献   

20.
The study was conducted to evaluate the effects of dietary butyrate loaded clinoptilolite (CLI-B) on growth performance, pancreatic digestive enzymes, intestinal development and histomorphology, as well as antioxidant capacity of serum and intestinal mucosal in chickens. Two hundred forty 1-day-old commercial Arbor Acres broilers were randomly assigned to 4 groups: CON group (fed basal diets), SB group (fed basal diet with 0.05% sodium butyrate), CLI group (fed basal diet with 1% clinoptilolite), and CLI-B group (fed basal diet with 1% CLI-B). The results showed that supplementation of CLI-B significantly decreased (P < 0.05) feed conservation ratio at both 21 and 42 days of age, improved the pancreatic digestive enzymes activities (P < 0.05), increased the villus length and villus/crypt ratio (P < 0.05), and decreased the crypt depth of intestine (P < 0.05) as compared to the other experimental groups. Furthermore, the CLI-B environment improved the antioxidant capacity by increasing the antioxidant enzyme activities (P < 0.05) in intestine mucosal, and decreasing the NO content and iNOS activity (P < 0.05) in serum. In addition, CLI-B supplementation had improved the development of intestine and antioxidant capacity of broilers than supplementation with either clinoptilolite or butyrate sodium alone. In conclusion, 1% CLI-B supplementation improved the health status, intestine development and antioxidant capacity in broiler chickens, thus appearing as an important feed additive for the poultry industry.  相似文献   

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