Effect of ochratoxin A on Escherichia coli-challenged broiler chicks

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli-challenged broiler chickens. Day-old broiler chicks were separated into two groups of 92 chicks each, with one group fed a control mash diet, and the other fed a mash diet containing 2 ppm OA. On day 14, each group was further separated into two groups, with one group inoculated with E. coli O78 (1 x 10(7) colony-forming units/0.5 ml), whereas the other group was not inoculated with E. coli. After E. coli inoculation on day 14, four birds from each group were euthanatized at 1, 2, 3, 5, 7, 10, 14, and 21 days postinoculation. Escherichia coli infection caused dullness, depression, huddling, and diarrhea. Mortality was 14.3% in chicks infected with E. coli but fed no OA. Mortality increased to 35.7% in chicks fed OA and infected with E. coli. Decreased body weight and reduced feed intake were observed in chicks fed OA, and the effects were more pronounced in chicks fed OA and infected with E. coli. Increased serum levels of aspartate aminotransferase, alanine aminotransferase, uric acid, and creatinine and decreased levels of total proteins, albumin, globulins, calcium, and phosphorus were observed in OA-fed birds. Escherichia coli infection did not cause significant alteration in any of the serum biochemical parameters. The presence of OA in poultry rations increased mortality and the severity of an E. coli infection.     

The individual and combined effects of citrinin and ochratoxin A in broiler chicks

Citrinin (CTN) and ochratoxin A (OA) were fed alone and in combination to broilers from day of hatch until 3 weeks of age. Dietary concentrations of 300 micrograms CTN/g and 3.0 micrograms OA/g were used. Birds fed CTN had significantly (P less than or equal to 0.05) lower body weights than controls on days 14 and 21 and increased water consumption on days 7, 14, and 21. Birds fed OA had significantly lower body weights than controls on days 7, 14, and 21 and increased water consumption on day 14. Birds fed CTN and OA in combination had lower body weights than controls and increased water consumption during the experiment, but the alterations were intermediate in severity when compared with those in birds fed CTN or OA alone. Birds fed OA alone or combined with CTN had higher liver and kidney weights than controls, but birds fed CTN alone had only higher kidney weights. Birds fed both CTN and OA had concentrations of serum constituents similar to those in birds fed OA alone, except the levels of cholesterol and triglycerides were not significantly different from those in the controls. Histological evaluation of the kidney indicated no lesions in birds fed CTN alone, but birds fed OA, alone or in combination with CTN, had increased tubular casts and tubular hyperplasia compared with controls. These data suggest that there were no additive or synergistic toxic interactions when 300 micrograms CTN/g and 3.0 micrograms OA/g were fed simultaneously to broiler chicks for 3 weeks. However, the severe growth depression resulting from OA and the increased water consumption associated with CTN toxicosis were ameliorated when CTN and OA were fed in combination. These data may be useful in diagnosing field cases of mycotoxicosis where both CTN and OA are involved.     

Effect of immunosuppression with cyclophosphamide, cyclosporin, or dexamethasone on Salmonella colonization of broiler chicks

One-day-old broiler chicks were divided into four groups: untreated controls and three groups treated with the immunosuppressive drugs cyclophosphamide, cyclosporin, or dexamethasone on days 1-4 of age. On day 5, all groups were challenged orally with 10(4) Salmonella typhimurium. Suppression of immunocompetency was demonstrated in the treatment groups by significant decrease (P less than 0.05) in weights of bursas of Fabricius, and diminished mitogen-induced T and B lymphocyte blastogenesis and cutaneous basophil hypersensitivity responses. There were no significant differences among the four groups in the number of Salmonella in the cecal contents or in the number of cecal-culture-positive chicks on day 10 post-challenge at 15 days of age. Results indicated that impairment of B or T lymphocyte responses had little influence on the resistance of young chicks to Salmonella cecal colonization.     

Skeletal changes in broiler chicks and turkey poults fed diets containing ochratoxin A

Broiler chicks and turkey poults were divided at hatching into experimental and control groups. Experimental birds were fed a diet contaminated with 4 ppm ochratoxin A, whereas the ration of control birds was confirmed to be mycotoxin free. Birds were killed at fortnightly intervals up to 10 weeks old and skeletal changes were investigated. Almost all experimental birds developed generalised skeletal osteopenia with disturbed endochondral and intramembranous bone formation. Histological changes in diaphyseal cortices could account for the reduced breaking strength of bones from birds fed mycotoxin, which have been reported by others. One bird showed changes consistent with a diagnosis of hypophosphataemic rickets. In others, however, osteoid formation was defective and changes were interpreted as osteoporosis. Although it might be tempting to suggest that osteoporosis is a result of a direct toxic effect of ochratoxin on osteoblasts, the effect of inanition, inactivity and general debility may be equally important.     

Effect of a selected Lactobacillus spp.-based probiotic on Salmonella enterica serovar enteritidis-infected broiler chicks

The effect of a Lactobacillus spp.-based probiotic (FM-B11) on Salmonella enterica serovar Enteritidis (SE) recovery was evaluated in liquid (Expt. 1) and lyophilized (Expt. 2) forms in two separate experiments with two trials each. For each trial, 80 broiler chicks were randomly allocated into two treatments: control and probiotic culture. All chicks were challenged with SE (approximately 10(4) colony-forming units [cfu]) upon arrival at our laboratory. In both experiments, probiotic culture was administered in the drinking water for 3 consecutive days at a final concentration of approximately 10(6) cfu/ml, beginning 1 hr after SE challenge. Cecal tonsils were aseptically removed at 24 and 72 hr postchallenge, followed by enrichment and plating on xylose lactose deoxycholate (XLD) agar for the presence or absence of Salmonella-typical colonies. In Expt. 1, a significant reduction (P < 0.05) in SE-positive samples was observed in both trials at 24 and 72 hr postchallenge. Additionally, in Expt. 2, the lyophilized probiotic decreased (P < 0.05) SE recovery at both 24 and 72 hr postchallenge compared with the control group in trial 1. In trial 2, SE evaluation was performed only at 72 hr after challenge and fewer (P < 0.001) treated samples were positive for SE. Results showed that application of either liquid or lyophilized probiotic culture in the drinking water for 3 consecutive days can help to reduce SE recovery from young birds, although further research is needed to elucidate the mechanism of this response.     

鸡沙门氏菌弱毒苗与微生态制剂联合应用的效果

将鸡沙门氏菌弱毒苗分别与2种不同的微生态制剂配合对AA肉鸡实施免疫。结果表明，弱毒苗单独应用组、联合应用1组和2组的免疫保护效率分别为75％、90％和90％，均与攻毒对照组（40％）存在显著差异（P＜0．05）；攻毒20d后所有存活鸡细菌分离结果显示，上述3个试验组细菌分离率分别为53．5％、55％和5．5％，也均与攻毒对照组（75％）存在显著性差异（P＜0．05）。由此认为，该弱毒苗与上述微生态制剂联合应用的效果明显，具有较好的应用前景。     

Effect of used litter from floor pens of adult broilers on Salmonella colonization of broiler chicks.

The effect of used pine-shaving litter from broiler floor pens on Salmonella colonization resistance was evaluated in broiler chicks. One-day-old chicks were placed in floor pens on fresh unused litter or on used litter. All chicks were challenged orally with 10(4) S. typhimurium at 3 days of age. The study was replicated in three trials with used litter that was collected and stored for 1 day (Trial 1), 4 days (Trial 2), or 50 days (Trial 3) before the start of each trial. Cecal concentrations of volatile fatty acids (VFAs) were significantly higher (P < 0.05) in chicks placed on used litter than in chicks on new litter. In all three trials, the number of Salmonella in the cecal contents and the number of Salmonella cecal-culture-positive chicks was significantly lower (P < 0.01) at 10 days and 20 days of age in the chicks on used litter than in the chicks on new litter. The results indicated that newly hatched chicks reared on used litter had higher cecal VFA concentrations and higher resistance to Salmonella colonization than chicks reared on new litter.     

Clinical effects and morphological changes after administration of low doses of ochratoxin A to broiler chicks]

Ochratoxin A (OA) was fed to HYBRO broiler chicks at a relatively low levels of 850 micrograms/kg up age 42 days. The effects of OA on chick development, health state and the patho-morphological lesions in internal organs were investigated in this experiment. The chicks exposed to the relatively low OA levels were observed to lag behind in their growth; this was confirmed by their regular weekly weighing when the lower liveweight in comparison with the control group was recorded from the age of 14 days. A decrease in the liveweight was statistically significant at the age of 21, 28 and 35 days. The patho-anatomic finding was negative. A histological examination of kidneys and liver revealed the pathological lesions typical for ochratoxicosis. The lesions observed included the dystrophy of the tubular epithelial cells (Fig. 1), eosinophil granules in the tubulus lumen (Fig. 3), dystrophic lesions in the glomerules (Fig. 2) and cellulization of the connective tissue of intertubular spaces (Fig. 1). The lesions of liver (Fig. 4) show to allergic responses and defense reactions of the organism to the OA action. On the basis of results it can be concluded that the relatively low ochratoxin levels cause histopathological lesions in the kidneys and liver of chicks, and in this way they can negatively influence their development and performance.     

Effect of stocking density on performance of broiler chicks

In two experiments space allowances of 0.143, 0.122, 0.105 and 0.093 m²/bird and 0.093, 0.078, 0.064 and 0.047 m²/bird were used and their effects on live‐weight, food consumption and food conversion of Cobb broilers up to 10 weeks old were measured.

When the space allowance was greater than 0.093 m²/bird there was no effect on any of the characters studied.

At 10 weeks old a decrease in space allowance from 0.093 to 0.047 m²/bird was accompanied by reduced final live‐weight and food consumption and increased efficiency of food conversion; the effect on live‐weight was smaller at 9 weeks and was not significant at 8 or 7 weeks.

It was concluded that in broiler experiments ending at 8 weeks a space allowance of 0.078 m²/bird (0.8 ft²/bird) is more than adequate.     

Oxygenated drinking water enhances immune activity in broiler chicks and increases survivability against Salmonella Gallinarum in experimentally infected broiler chicks

It has been suggested that drinking oxygenated water may improve oxygen availability, which may increase vitality and improving immune activity. The present study evaluated the immune enhancing effects of oxygenated drinking water in broiler chicks and demonstrated the protective efficacy of oxygenated drinking water against Salmonella Gallinarum in experimentally infected broiler chicks. Continuous drinking of oxygenated water markedly increased serum lysozyme activity, peripheral blood mononuclear cell proliferation and the CD4(+)/CD8(+) splenocyte ratio in broiler chicks. In the chicks experimentally infected with S. Gallinarum, oxygenated drinking water alleviated symptoms and increased survival. These findings suggest that oxygenated drinking water enhances immune activity in broiler chicks, and increases survivability against S. Gallinarum in experimentally infected broiler chicks.     

Effects of probiotics and maternal vaccination on Salmonella enteritidis infection in broiler chicks

The effects of probiotics and maternal vaccination with an inactivated Salmonella Enteritidis (SE) vaccine on day-old chicks challenged with SE were evaluated. A 2 X 3 factorial arrangement was used (with or without probiotics; breeders nonvaccinated, vaccinated intramuscularly, or vaccinated intraperitoneally). Three trials were conducted in isolation cabinets and SE challenge was different between trials. The number of SE organisms per chick and the time interval between housing and introduction of seeder birds (hereafter called challenge) were 1.6 X 10(8) and 1 hr (Trial I), 1.8 X 10(6) and 12 hr (Trial II), and 1.2 X 10(4) and 24 hr (Trial III). SE recovery was assessed in ceca and liver at 3, 5, and 7 days postchallenge, and the number of colony-forming units (CFU) in ceca was evaluated at 5 and 7 days postchallenge. The number of SE (log CFU) in the ceca reduced 0.56 log (from 7.59 to 7.03) and 1.45 log (7.62 to 6.17) because of the treatment with probiotics in Trials II and III, respectively. The greater reduction in Trial III indicates the importance of the early use of probiotics on the prevention of SE infection. Treatment with probiotics resulted in a smaller number of SE-positive livers after 5 days postchallenge on Trial III. Although there was no significant effect of maternal vaccination on the number of SE CFU in the ceca, a significant effect of maternal vaccination on the SE CFU was observed in the liver, but not in the ceca at 5 days after challenge.     

叶酸对肉仔鸡营养物质利用的影响

选用艾维茵商品代白羽肉鸡120只,随机分成4组,按叶酸添加水平不同分为4个不同处理组,分别为0、0.75、1.5、3.0mg/kg,于35～42日龄用全收粪法进行消化代谢试验,研究叶酸对肉仔鸡营养物质利用率的影响。研究结果表明,添加叶酸可以不同程度地提高饲料养分表观利用率,1.5mg/kg组的干物质、粗蛋白、粗脂肪、粗纤维、有机物和无氮浸出物的表观代谢率最高,分别比对照组提高10.33%、19.83%、14.32%、13.89%、6.07%和16.09%,差异显著,而其余各养分的代谢率各组间均差异不显著。     

Salmonella gallinarum field isolates of the biovars pullorum and gallinarum

In 40 cases salmonellae of the serovar Salmonella (S.) gallinarum were culturally isolated from domesticated gallinaceous birds submitted for diagnostic purposes in the period of 1979-1989. On the basis of the cultural and biochemical features found 35 of them could be assigned to the biovar Pullorum and 5 to the biovar Gallinarum. Of 35 isolates of the biovar Pullorum, 29 were isolated from pure bred chickens of small fancy-exhibition type flocks, 4 from floor-housed adult brown hybrid laying hens and one each from broiler chicks and pheasant chicks (Phasianus colchicus). Acute to subacute courses of the pullorum disease were observed in the 4 flocks of brown hybrid hens. Of 5 isolates of the biovar Gallinarum, 4 were isolated from adult brown hybrid laying hens kept in battery cages and one from floor-housed brown hybrid pullets of the laying type. First cases of fowl typhoid occurred early in the summer of 1988. The disease was characterized by a peracute course in the 4 flocks of brown laying hens and by a more acute course in the pullet flock. The primary source of the fowl typhoid producing organisms was not elucidated.     

Increased survival from acute Salmonella gallinarum infection in chicks given diets with high levels of some forms of iron

Amounts exceeding 100 ppm of extra dietary iron as the ferric salts of ethylenediaminetetra-acetic acid (FeE) or nitrilotri-acetic acid (FeN) produced highly significant increases in survival among chicks infected with 10(6.4) living Salmonella gallinarum strain 9. Additional dietary iron (400 ppm) as the sulphate or chloride salts (or as ferric fructose) lacked activity comparable with FeE or FeN except when 0.2 per cent of NaE was also present in the diet. FeE iron (600 ppm) also diminished the severity of several of the pathological reactions which occur in chicks during the acute stage of experimental fowl typhoid. The enhanced survival and decreased severity of the pathological changes in infected chicks were associated with large reductions in the numbers of viable salmonellae in the spleen at the height of the acute infection.     

Salmonella enterica serovar enteritidis burden in broiler breeder chicks genetically associated with vaccine antibody response

The relationship between antibody response to Salmonella enteritidis vaccine and internal organ burden of S. enteritidis is not fully understood. The genetic relationship, therefore, between postchallenge S. enteritidis burden and antibody response to S. enteritidis vaccine was determined in broiler breeder chicks. Sibling chicks from a broiler breeder male line were either inoculated with a pathogenic S. enteritidis or vaccinated with a commercial S. enteritidis vaccine. Spleen, liver, cecal wall, and cecal content samples from S. enteritidis-challenged chicks (n = 120) were cultured for enumeration of bacteria. Unchallenged chicks (n = 314) were vaccinated at 11 days of age, and serum samples were taken at 10 days postvaccination. Antibody response to vaccination and number of S. enteritidis in cecal content cultures were negatively correlated (-0.772), demonstrating that genetic potential for greater antibody response to S. enteritidis vaccine is associated with lesser S. enteritidis bacterial burden in cecal content of broiler breeder chicks. The findings suggest that genetic selection for vaccine antibody responsiveness can lower bacterial burden in the gut lumenal content and, thus, potentially reduce contamination of poultry products at processing.     

Effect of dietary lactose on cecal pH, bacteriostatic volatile fatty acids, and Salmonella typhimurium colonization of broiler chicks

One-day-old broiler chicks were inoculated with volatile fatty acid producing cecal flora from adult chickens. The chicks were divided into four groups and provided 1) no lactose, 2) 2.5% lactose in water, 3) 5% lactose in feed, or 4) 10% lactose in feed, until 10 days of age. All groups were challenged at 3 days of age with 10(6) or 10(8) S. typhimurium. At 10 days, the number of Salmonella in the ceca of the chicks challenged with 10(6) Salmonella was significantly decreased (P less than 0.01) in the groups provided lactose as compared with the controls. A significant decrease (P less than 0.01) in Salmonella numbers occurred in the chicks challenged with 10(8) Salmonella and provided 10% lactose. Providing 2.5% lactose or 5% lactose failed to inhibit Salmonella growth in chicks challenged with 10(8) Salmonella. The pH of the ceca of the groups provided lactose decreased significantly (P less than 0.05) and was accompanied by significant increases (P less than 0.01) in the concentrations of bacteriostatic acetic and propionic acids. Results showed that providing dietary lactose to broiler chicks and inoculation with normal cecal flora decreased cecal pH, increased the concentrations of bacteriostatic volatile fatty acids, and inhibited Salmonella colonization.     

Effect of growth promoters on monensin toxicity in broiler chicks 1

1. An experiment was carried out with male broiler chicks to evaluate the combined effect of monensin (150 mg/kg) and the growth promoters (GPs) Zn bacitracin (BAC, 50 mg/kg), virginiamycim (VIR, 25 mg/kg) and avoparcin (AVO, 20 mg/kg) fed from 7 to 28 d of age on performance, utilisation of dietary nutrients, yield of defeathered eviscerated carcases (DEC) and size of various organs. The effect of the GPs in the monensin‐unsupplemented diets fed up to 49 d of age on performance and carcase was also determined.

2. Monensin significantly (P < 0.05) depressed food intake, weight gain and food efficiency from 7 to 28 d of age. None of the GPs was able to counteract these effects. However, AVO slightly ameliorated them. AVO also significantly increased food intake and improved gain and food efficiency during 7 to 28, but not 28 to 49 or 7 to 49 d of age. VIR and BAC did not affect performance in either age period.

3. Monensin did not affect the utilisation of dietary dry matter, fat or energy, but it significantly decreased nitrogen utilisation. AVO improved nitrogen and fat utilisation and increased dietary AME_n content. AME_n was also increased by VIR. The utilisation of these nutrients was not affected by the interactions between monensin and the GPs.

4. Monensin did not affect yield of the DEC or the relative liver size at 31 d of age. It significantly increased the relative length of the small intestine (SI) and decreased its specific weight. AVO significantly increased yield at 31, but not at 53 d of age. BAC and VIR did not affect this variable. AVO and VIR, but not BAC, at both age periods reduced, at times significantly, the size, length and specific weight of the SI.

5. Our conclusions: BAC, VIR and AVO do not counteract the toxic effect of monensin. The effect of GPs in improving performance decreases and even disappears with age, while their effect in reducing the size of the SI is still evident in 49‐d‐old birds.