Dexamethasone reduces infectious bursal disease mortality in chickens.

Very virulent infectious bursal disease virus (vvIBDV) causes high mortality in chickens but measures to reduce the mortality have not been explored. Chickens (8-9 weeks) were treated with 3 agents before and during vvIBDV inoculation. Dexamethasone treatment reduced the mortality of infected chickens (40.7% vs. 3.7%; p < 0.001), but treatment with aspirin or vitamin E plus selenium did not affect the mortality. The bursa of Fabricius appeared to have shrunk in both dead and surviving chickens (p < 0.01). The results indicate that dexamethasone can reduce mortality in vvIBDV-infected chickens and may provide therapeutic clues for saving individual birds infected by the virus.

Epidemiological assessment of the factors associated with antimicrobial use in French free-range broilers.

BACKGROUND: Although the poultry sector accounts for a major portion of global antimicrobial consumption, few studies have explored the factors which influence antimicrobial use (AMU) in poultry farms in Europe. We performed a matched case-control study in traditional free-range broiler farms in France during 2016 to evaluate the effect of technical factors and farmers' perceptions of health problems on the probability of AMU. In total, 52 cases (defined as flocks treated with antimicrobials when chickens were between 1 and 42 days old), were included. Another 208 controls (untreated flocks the same ages as the case flocks), were randomly selected and paired with a matching case (same farmer organization and placement date). On-farm questionnaires were administered. Multivariable logistic regression modeling was conducted; seven variables were significant in the final model. RESULTS: Two factors were associated with a lower probability of AMU: the use of chicken paper topped with starter feed (OR = 0.3; 95% CI = [0.1; 0.9]) and the use of herbal drugs as a prophylaxis (OR = 0.1; 95% CI = [0.01; 0.5]). A higher probability of AMU was associated with farmers perceiving the cumulative mortality of chicks between 1 and 10 days old as normal (OR = 10.1; 95% CI = [1.7; 59]) or high (OR = 58.7; 95% CI = [9.6; 372.3]). A higher probability of AMU also was associated with farmers detecting a health problem (OR = 12.5, 95% CI = [4.2; 36.9]) and phone calls between farmers and their technicians (OR = 5.9; 95% CI = [2.3; 14.8]) when chicks are between 11 to 42 days old. Two additional factors (litter thickness and cleaning/disinfecting) were significant and highlighted the importance of technical factors such as biosecurity. CONCLUSIONS: Our results suggest that to reduce AMU, technical training should be provided to farmers to improve how farms are monitored and to reinforce preventive health measures. Training also should address how farmers assess warning criteria like daily mortality rates, which when overestimated often lead to antimicrobial treatment.

Supplemental thymol and carvacrol increases ileum Lactobacillus population and reduces effect of necrotic enteritis caused by Clostridium perfringes in chickens.

Necrotic enteritis (NE) caused by Clostridium perfringens is one of the most detrimental infectious diseases in poultry. This study examined the effect of blends of essential oils (BEOs) (25% thymol and 25% carvacrol) on NE and bacterial dynamics and functions in chicks challenged with C. perfringens. Chicks were assigned to a Control diet and BEOs diet (Control diet + 120 mg/kg BEOs), were challenged with C. perfringens from days 14 to 20 and were killed on day 21 for assessment. Supplementation with BEOs decreased the mortality, alleviated gut lesions, and decreased the virulence factors of pathogenic bacteria (VF 0073-ClpE, VF0124-LPS, and VF0350-BSH). Lack of supplementation also changed the nutrient and immunological dynamics of host microbiota in responding to C. perfringens infection. Adding BEOs changed the host ileum microbial population by increasing the numbers of Lactobacillus crispatus and Lactobacillus agilis, and decreasing Lactobacillus salivarius and Lactobacillus johnsonii. The functional roles of these changing host bacterial populations coupled with the putative reduced pathogenicity of C. perfringens by BEOs contributed to the reduction in gut lesions and mortality in infected chickens. It suggests that dietary supplementation with BEOs could significantly reduce the impact of NE caused by C. perfringens on broilers.

Anticoccidial effects of Aloe secundiflora leaf extract against Eimeria tenella in broiler chicken.

Anticoccidial effects of Aloe secundiflora crude leaf extract was tested in broiler chickens following oral infection with Eimeria tenella. Sixty 22-day-old birds were divided into six groups of ten birds each. Three treatment groups A, B, and C were fed with the extract (100, 250, and 500 mg/day, respectively) mixed in feed for 10 days, and three control groups: group D (drug control) administered 300 mg/l of sulfachloropyrazine sodium soluble powder in drinking water for 5 days, group E (infected/non-medicated positive control), and group F (uninfected/non-medicated negative control). Except for group F, all groups were orally inoculated with 75,000 sporulated oocysts of E. tenella. The effects of the extract on E. tenella infection were evaluated by severity of bloody diarrhea, body weight (BW) gain, oocyst output, and lesion score. No bird in the treated groups died of coccidiosis, and severity of bloody diarrhea was milder than in the positive control group. BW gains in the treated groups were significantly higher than in group E (p < 0.05). The lesion scores of the treated groups were significantly lower than that of group E. Oocyst output in groups A, B, and C were 11.23, 8.24, and 6.82 × 106, respectively. As compared with the negative control group (12.84 × 106), the reductions in oocyst production were 12.54, 35.83, and 46.88%, respectively. Oocyst output significantly reduced with an increase in Aloe dosage. The findings of this study suggest that Aloe secundiflora extract presents an alternative anticoccidial agent for the control of avian coccidiosis.

Efficacy of avilamycin for the prevention of necrotic enteritis caused by a pathogenic strain of Clostridium perfringens in broiler chickens.

The efficacy of avilamycin for the prevention of necrotic enteritis (NE) was investigated in a 35-day floor pen study of 2200 broiler cockerels using a Clostridium perfringens (Cp) feed inoculum challenge model. Treatments consisted of (1) nonmedicated, nonchallenged; (2) nonmedicated, challenged; (3) avilamycin at 15 ppm, challenged; (4) avilamycin at 30 ppm, challenged. Avilamycin was administered in the feed from day 7 to day 30 of the study. Challenge inoculum was administered on day 14 and delivered approximately 10(9) CFU Cp/bird. NE mortality rates from day 14-35 were significantly (P < 0.0001) lower in birds treated with avilamycin at 15 and 30 ppm when compared to nonmedicated, challenged birds. Treatment with avilamycin also resulted in a significant reduction in ileal Cp count on day 21 (P < 0.0001) and NE lesion scores on day 17 (P < 0.006) when compared to nonmedicated, challenged birds. The performance of birds treated with avilamycin was also improved when compared to nonmedicated, challenged birds. Cockerels that received either 15 or 30 ppm avilamycin had a significantly (P < 0.0001) increased body weight on day 35 and average daily gain from days 0-35 than nonmedicated, challenged birds. Furthermore, birds treated with avilamycin had an improved feed conversion rate from days 0-35 compared to both nonmedicated, nonchallenged birds and nonmedicated, challenged birds. This study confirms that avilamycin is effective at controlling mortality related to NE in growing broiler chickens.

Pulmonary hypertension and right ventricular failure in broiler chickens reared at high altitude is affected by dietary source of n-6 and n-3 fatty acids.

The present study evaluated the development of pulmonary hypertension and right ventricular failure in broiler chickens reared at high altitude (2100 m) as affected by dietary intake of n-3 and n-6 fatty acid sources. Flax oil and soy oil were used as sources of n-3 and n-6 fatty acids, respectively, either with or without α-tocopheryl acetate. A total of 192 day-old broiler chicks (Ross 308) were used in a completely randomized design using isoenergetic and isonitrogenous experimental diets. Results showed that dietary flax oil significantly (p < 0.05) improved feed conversion ratio during 21-42 days of age. However, body weight gain did not significantly differ among the experimental groups in entire trial. Birds received flax oil had significantly higher serum concentration of nitric oxide (NO) but they had lower serum concentration of malondialdehyde when compared with their counterparts fed with soy oil. Liver and abdominal fat weights were significantly (p < 0.05) reduced by substitution of soy oil for flax oil. The right-to-total ventricle weight ratio (RV/TV) and mortality from pulmonary arterial hypertension (PAH) were significantly (p < 0.05) decreased in birds that received flax oil. In conclusion, n-3 fatty acids could significantly reduce RV:TV and PAH mortality in birds by increasing circulatory level of NO and suppressing hepatic lipogenesis.

Antiviral effect of sulfated Chuanmingshen violaceum polysaccharide in chickens infected with virulent Newcastle disease virus.

Newcastle disease virus (NDV) belonging to the Paramyxovirinae subfamily is one of the most devastating pathogens in poultry. Although vaccines are widely applied to control the infection, outbreaks of Newcastle disease (ND) repeatedly happen. Currently, there are no alternative control measures available for ND. In the present study, we found that sulfated Chuanmingshen violaceum polysaccharide (sCVPS) were potent inhibitors of NDV in specific pathogen free chickens infected with a virulent strain. With sCVPS treatment, the survival rate increased by almost 20% and virus titers in test organs, including brain, lung, spleen and thymus, were significantly decreased. The sCVPS also exhibited the ability to prevent viral transmission by reducing the amount of virus shed in saliva and feces. Higher concentrations of interferon α and γ in serum were detected in chickens treated with sCVPS, indicating that one of the antiviral mechanisms may be attributed to the property of immunoenhancement. Histopathological examination showed that sCVPS could alleviate the tissue lesions caused by NDV infection. These results suggest that sCVPS are expected to be a new alternative control measure for NDV infection and further studies could be carried out to evaluate the antiviral activity of sCVPS against other paramyxoviruses.

Liver pathology associated with increased mortality in turkey breeder and meat turkey flocks.

Between 2006 and 2011 a series of disease conditions characterized by raised mortality and liver disorders occurred in turkey breeder flocks and in meat turkey flocks in Germany. The flocks were between 12 and 23 wk of age, and mostly hens were affected. Clinical signs were nonspecific and accompanied by mortality varying between 1% and 7%. Affected birds displayed swollen livers that were marbled with black and red spots and yellowish areas. The pericardium was filled with an amber fluid, and the coronary groove was extensively filled with fat. Spleens were swollen, and a serous fluid that seemed to leak from the liver was present in the body cavity. Histopathological findings in all but one case included fatty degeneration of hepatocytes with parenchymal collapse and associated hemorrhages. Some animals showed cholangitis and hepatitis with intranuclear inclusion bodies. In three cases with breeders, electron microscopy detected virus particles that were between 23 and 30 nm and similar to parvo- or picornavirus. In addition, picornavirus RNA was detected in the livers of one meat turkey flock. Investigations by PCR for circovirus, polyomavirus parvovirus, and aviadenovirus yielded negative results in all cases, but an aviadenovirus was isolated from livers twice and a reovirus from the intestines once. Supplementation with vitamin E and selenium seemed to improve the situation. The most likely diagnosis is lipidosis, a metabolic disorder with complex etiology, which has rarely been described in turkeys.

Polyphenol extracts from Punica granatum and Terminalia chebula are anti-inflammatory and increase the survival rate of chickens challenged with Escherichia coli.

Avian pathogenic Escherichia coli (APEC) causes inflammation in multiple organs of chickens called avian colibacillosis, and results in serious economic loss to the chicken industry. Polyphenolic compounds possess a wide range of physiological activities that may contribute to their beneficial effects against inflammation-related diseases. In this study, the curative effect and mechanism of action of the polyphenolic extracts from Punica granatum L. and Terminalia chebula Retz. in chickens challenged with APEC were studied. Specific-pathogen-free white Leghorn chickens (males, 21-d old) were challenged with APEC and then given oral administration of extracts of P. granatum and T. chebula. The extracts decreased the morbidity and inflammation induced by APEC. Data from quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay showed that the extracts of P. granatum and T. chebula polyphenols (GCP) reversed the over-expression genes of the Toll-like receptor (TLR) 2, 4, and 5, down-regulated the activation of nuclear factor-kappa B signal transduction pathways, and inhibited the production of pro-inflammatory cytokines. Naturally occurring GCP may be a potential alternative medicine for the prevention or treatment of avian colibacillosis.

In vivo screening of five phytochemicals/extracts and a fungal immunomodulatory protein against colibacillosis in broilers.

Five phytochemicals/extracts (an extract from Echinacea purpurea, a ß-glucan-rich extract from Shiitake, betaine [Betain™], curcumin from Curcuma longa [turmeric] powder, carvacrol and also a recombinant fungal immunomodulatory protein [FIP] from Ganoderma lucidum) cloned and expressed in Escherichia coli were investigated for their anticolibacillosis potential in three chicken experiments, which were conducted in floor pens. Birds that were inoculated with E. coli intratracheally were treated with the phytochemicals/extracts or the FIP and compared with doxycycline-medicated and non-medicated infected broilers. Non-medicated and non-infected birds were used as negative controls. Mortality, colibacillosis lesions and body weight gains were used as parameters. Considering the sum of dead birds and chickens with generalized colibacillosis per group, there was no significant difference between the positive control groups and birds treated with phytochemicals/extracts or the FIP. In contrast, doxycycline-treated birds showed significantly lower mortality and generalized colibacillosis. Moreover, none of the phytochemicals/extracts and the FIP improved recovery from colibacillosis lesions, while all doxycycline-treated broilers recovered completely. The negative control birds and doxycycline-treated groups consistently showed the highest weight gains. Pulsed-field gel electrophoresis of reisolates showed that they were genetically indistinguishable from the inoculation strain. In conclusion, none of the tested phytochemicals/extracts and the FIP significantly reduced the E. coli-induced mortality and generalized colibacillosis, and nor did they improve recovery from colibacillosis lesions.

The effects of dietary non-starch polysaccharides on Ascaridia galli infection in grower layers.

This study examined whether Ascaridia galli infection can be controlled by dietary non-starch polysaccharides (NSP) in chickens. One-day-old chicks were fed either a basal diet (CON) or CON plus insoluble NSP (I-NSP), or CON plus soluble NSP (S-NSP) for 11 weeks. Three weeks later, birds from half of each feeding group were inoculated with 250 embryonated eggs of A. galli, and slaughtered 8 weeks post-infection to determine worm counts. Both NSP diets, particularly S-NSP, increased prevalence of infection (P<0·05) and worm burden (roughly +50%) of the birds (P<0·001). A. galli infection caused a less efficient (P=0·013) feed utilization for body weight gain (BWG) resulting in lower body weights (P<0·001) irrespective of type of diet consumed. NSP-fed birds, particularly those on I-NSP, consumed more (+8%) feed per unit BWG and showed retarded (P<0·001) BW development compared to CON-fed birds. Intracaecal pH was lowered by S-NSP (P<0·05). Both NSP diets increased the volatile fatty acids pool size in caeca (P<0·001) with S-NSP exerting a greater effect (+46%) than I-NSP (+24%). It is concluded that both NSPs supplemented diets alter gastrointestinal environment in favour of the nematode establishment, and thus have no potential for controlling A. galli infection in chickens.

Xiang-qi-tang increases avian pathogenic Escherichia coli-induced survival rate and regulates serum levels of tumor necrosis factor alpha, interleukin-1 and soluble endothelial protein C receptor in chicken.

Xiang-qi-tang (XQT) is a Chinese herbal formula containing rhizoma Cyperi, Andrographis paniculata and Astragalus membranaceus. The present study investigated the effects of XQT on the mortality and inflammatory mediators in a chicken model challenged with avian pathogenic Escherichia coli (APEC). To detect the effect of XQT, the chickens were pretreated with the formula 12 h before being challenged with 10(8) colony forming unit (CFU) of APEC. The results showed that 0.6 g/kg XQT significantly elevated the survival rate of infected chickens. To further investigate the mechanism of decreasing mortality of XQT, we examined plasma inflammatory mediator levels. The levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1) and soluble endothelial protein C receptor (sEPCR) were significantly increased in chickens challenged with APEC alone, whereas chickens pretreated with 0.6 g/kg XQT showed marked decrease of these inflammatory mediator levels during the death peak. Taken together, this study demonstrates that XQT has protective effects in APEC-treated chickens. The action mechanisms of XQT involve anti-inflammation and antithrombotic activity. These findings may contribute to future research on the action mechanisms of this formula, as well as prevention of or therapy for avian colibacillosis.

Impact of synergism of calcium phosphomycin/tylosin tartarate supplements on the performance of broilers in the Lebanon.

The authors evaluate the impact of a synergistic preparation (SP) of supplements (a combination of calcium phosphomycin and tylosine tartarate) on the performance of broilers with a history of carcass condemnation at slaughter. The experiment included 120-day old broilers (Ross 308), divided equally into two treatment groups, with three replicates per treatment and 20 birds per replicate. The two groups included controls that did not receive SP and those that were treated with SP. The SP group received treatment at three intervals (at 1-5 days of age: 160 mg/kg body weight; at 21-25 days of age: 80 mg/kg; and at 29-33 days of age: 80 mg/kg body weight). The administration of SP at a low level improved performance in SP birds compared to controls and also resulted in the lowest cumulative mortality (1.67% vs 6.67%, respectively), the lowest feed conversion of 1.91 between 1 and 43 days of age and the highest live body weight (2,544.75 g vs 2,390.18 g). The administration of SP at a low level improved performance and reduced the frequency of specific gross lesions at market age (tracheitis, lung congestion, breast blisters and bursal congestion).

Immune interference of bacteriophage efficacy when treating colibacillosis in poultry.

A study was conducted to determine if prior exposure with bacteriophage would limit the ability of the same bacteriophage to treat colibacillosis. There were 5 treatments with 3 replicate pens of 20 birds per pen. The treatments consisted of 1) control, 2) birds treated with bacteriophage at 10 and 17 d of age, 3) birds challenged with Escherichia coli at 17 d of age, 4) birds challenged with E. coli and treated with bacteriophage at 17 d of age, and 5) birds treated with bacteriophage at 10 d of age and challenged with E. coli and treated with bacteriophage at 17 d of age. Colibacillosis was induced by injecting 0.1 mL of E. coli into the thoracic airsac containing 1 x 10(6) cfu. The bacteriophage was administered by i.m. injection of 0.1 mL into the thigh, providing a dose of 6.8 x 10(8) pfu. The study was concluded 14 d after E. coli challenge. Mortality in the birds challenged with E. coli and not treated with bacteriophage was 55% (treatment 3), and bacteriophage therapy significantly (P < or = 0.05) reduced mortality to 8% (treatment 4), which was not significantly (P < or = 0.05) different from the 2 non-E. coli-challenged controls (3%, treatment 1, and 2%, treatment 2). However, mortality in the birds administered bacteriophage before challenge with E. coli and treated with bacteriophage (treatment 5) was 33%, which was not significantly different (P < or = 0.05) from the birds that were challenged with E. coli and untreated (55%, treatment 3). A kinetic in vitro assay of bacteriophage activity found that serum from birds pretreated with bacteriophage (treatment 5) inhibited bacteriophage activity. The IgG levels to the bacteriophage in serum from birds pretreated with bacteriophage (treatment 2) were significantly higher at all dilutions compared with control serum (treatment 1). These data demonstrate that prior exposure to bacteriophage will limit bacteriophage therapeutic efficacy and suggests that the reduced efficacy is due to an immune response to bacteriophage.

Risk and indicators of condemnation of male turkey broilers in western France, February-July 2006.

A field study was conducted to estimate the sanitary condemnation proportion in male turkey broiler flocks, to describe the reasons for condemnation and the related macroscopic lesions, and to investigate whether primary production information would predict the risk of condemnation. Male turkey standard broiler flocks (117) were randomly selected in the 13 slaughterhouses located in Western France, from February to July 2006. The flocks were monitored from their arrival at the slaughterhouse until the results of the post mortem sanitary inspection. Information about rearing conditions, health history, catching and loading conditions, transportation to the slaughterhouse and slaughtering was also collected. Sampling design was considered in the calculations and the condemnation proportion was modelled using a negative binomial regression, accounting for clustering within slaughterhouse. The within-flock weighted average condemnation proportion was 1.8% (95% confidence interval, 1.3-2.3%). Emaciation, arthritis-polyarthritis and congestion were the main reported official reasons for condemnation, representing 76% of the condemned carcases. Three variables were significantly associated with increased risk of condemnation: observed locomotor disorders on the farm, high cumulative mortality 2 weeks before slaughter, and clinical signs observed by the Veterinary Services during the ante mortem inspection at the slaughterhouse. The final model explained 35% of the total variation in condemnation risk. Half of this explained variation could be attributed to locomotor disorders observed during rearing. The sensitivity and specificity of the model to predict a high flock condemnation risk were 80% and 74%, respectively, when using an optimum threshold of 0.95% to define high risk. The results of this study suggested that the variables found to be associated with condemnation proportion were markers of increased risk and could be used as indicators. These risk indicators can easily be retrieved from the pre-existing regulatory document transmitted before flock arrival at the slaughterhouse and could be used to screen flocks before slaughter, according to their expected risk of condemnation.

Effects of diet type and enzyme addition on growth performance and gut health of broiler chickens during subclinical Clostridium perfringens challenge.

The effects of diet type (corn- vs. wheat-based) and multicarbohydrase addition on growth performance, digesta pH and viscosity, intestinal populations of Clostridium perfringens and lactic acid bacteria, and gut lesion score (from 0 to 4, where 0 = no gross lesions, 4 = severe extensive necrosis) of broiler chickens during oral challenge with C. perfringens (none or 10(8) cfu/bird on d 13) were studied in a 39-d experiment. A total of 1,216 male Ross-308 chickens was assigned to 8 dietary treatments in a randomized complete block design providing 8 replicate pens per treatment. Diets were formulated to meet the NRC protein requirement but were suboptimal in energy level. When compared with birds fed corn-based diets, chickens fed wheat-based diets had inferior (P < 0.01) final BW (2.49 vs. 2.59 kg) and feed conversion ratio (FCR; 1.83 vs. 1.78). Pathogen challenge significantly (P < 0.05) impaired growth performance and increased C. perfringens numbers and average lesion score. Increased (P < 0.01) C. perfringens counts (2.4 vs. 1.5 log(10) cfu/g of digesta) and intestinal lesion score (0.9 vs. 0.4) were observed for challenged birds fed wheat-based diets. No difference in digesta pH and lactic acid bacteria numbers were found among the treatments. Enzyme addition to both the corn- and wheat-based diets increased bird final BW (2.57 vs. 2.51 kg; P < 0.01), decreased overall FCR (1.78 vs. 1.83; P < 0.01), and, in those consuming wheat-based diets, reduced digesta viscosity (from 4.1 to 2.7 mPa.s; P < 0.01). Enzyme supplementation assisted the challenged birds in maintaining their optimal growth performance by improving (P < 0.05) average daily gain (59.5 vs. 56.9 g) in those consuming corn-based diets and FCR (1.83 vs. 1.90) in those consuming wheat-based diets to values similar to those observed in control birds (59.7 g/d and 1.84, respectively). In conclusion, enzyme addition improved growth performance and mitigated the negative effects of C. perfringens challenge.

Lack of prolonged activity of lavender essential oils as acaricides against the poultry red mite (Dermanyssusgallinae) under laboratory conditions.

Managing the poultry red mite, Dermanyssusgallinae (De Geer) by conventional means (i.e., synthetic acaricides) has become increasingly problematic. As a possible alternative, research has identified several plant essential oils that are toxic to D. gallinae. However, essential oils are highly volatile and any acaricidal effect they exert could be short-lived in practice. This study investigated the short-lived toxicity of six lavender essential oils to D. gallinae. In sealed Petri-dishes, mites were exposed to filter papers impregnated with essential oil at a concentration of 0.14mg/cm(3). When filter papers were used immediately after impregnation, 66-90% D.gallinae mortality was observed after 24h, depending upon the essential oil used. If impregnated filter papers were left in a fume cupboard for 24h prior to use, mortality rates of D.gallinae fell to 11% or less.

The effect of dietary l-carnitine supplementation on pulmonary hypertension syndrome mortality in broilers exposed to low temperatures.

Oxidative stress is involved in the development of pulmonary hypertension syndrome (PHS) in broilers. l-Carnitine has an antiperoxidative effect and supplemental l-carnitine has been revealed to increase broiler heart weight. The present study was conducted to evaluate the effect of an addition of 100 mg/kg l-carnitine to the basal diets on PHS mortality in cold-exposed broilers. Two-hundred and forty mixed-sex broilers were equally assigned to three groups. The control group was reared in normal temperatures throughout the experiment. Starting on day 14 continuing until the end of the experiment, the other two groups were subjected to a step-down temperature programme (by lowering the temperature 1-2 degrees C per day down to 12-14 degrees C) with or without l-carnitine added to the basal diets. Cold exposure increased the right/total ventricle ratio (RV/TV) and plasma malondialdehyde (MDA), reduced superoxide dismutase (SOD) and led to pulmonary vascular remodelling in birds without feeding additional l-carnitine. Supplemental l-carnitine reduced plasma MDA, increased SOD, inhibited remodelling and postponed the occurrence of PHS for 1 week in cold-exposed broilers; nevertheless, it did not significantly influence the cumulative PHS mortality (p > 0.05). On days 24 and 32, birds fed supplemental l-carnitine had lower RV/TV and higher total ventricle/body weight (p < 0.05) but unchanged right ventricle/body weight ratios (p > 0.05) compared to their cold-exposed counterparts, indicating an increase in left ventricle weight. However, from day 39 on, their RV/TV ratios were suddenly increased (p < 0.05). It was suggested that the l-carnitine-induced increase in left heart weight might partially account for the postponed occurrence of pulmonary hypertension in the early stage by elevating cardiac output, which might, in turn, lead to the resulting increase in pulmonary pressure. In view of its complex effects on cardiopulmonary haemodynamics, l-carnitine supplementation may be impractical for reducing PHS.

Excessive dietary vitamin D supplementation as a risk factor for sudden death syndrome in fast growing commercial broilers.

Broiler diets are frequently fortified with vitamin D (D3) above the recommended levels in an attempt to prevent commonly occurring leg problems. Since the basal levels of dietary D3 are rarely known, there is a risk of over-supplementation. Over-supplementation of D3 has been shown to have detrimental effects on the heart. Sudden death syndrome (SDS) is a condition commonly observed in broiler flocks and is associated with acute heart failure. The present study examines the effects of excessive levels of vitamin D3 on cardiac health in fast growing broiler chickens. Commercial male broilers (Gallus gallus) were exposed to either a commercial diet or a commercial diet supplemented with D3. Throughout the trial all birds were monitored several times daily for overt signs of heart disease, and periodically electrocardiographic measurements were obtained. Morbidity and mortality data were collected daily. On day 32 a simulated stress challenge consisting of a single injection of epinephrine (100 microg/kg BW) was administered under continuous ECG monitoring. Broilers fed the high D3 diet were 2.5 fold more likely to succumb to acute heart failure and die of SDS (p<0.05). Electrocardiographic examination showed a higher rate of cardiac arrhythmia in birds fed the high D3 diet (22.6%), in comparison to those fed the control diet (11.8%). The stress challenge test revealed that broilers exposed to high dietary D3 were more susceptible to ventricular arrhythmia. Our findings indicate that over-supplementation of vitamin D increases the risk of SDS in broilers, and that the most likely mechanism is associated with increased susceptibility of the ventricular myocardium to arrhythmia.

Efficacy of a herbal product against Histomonas meleagridis after experimental infection of turkey poults.

Histomoniasis (infectious enterohepatitis, blackhead) is caused by the protozoan parasite Histomonas meleagridis (H. meleagridis). After the ban of all prophylactic and therapeutic drugs in the European Union, histomoniasis is increasingly responsible for considerable economic problems to the poultry industry. The aim of this study was to investigate the effect of a herbal product with extracts from cinnamon, garlic, lemon, and rosemary on H. meleagridis in turkey poults in vivo. For this purpose, 60 two-week-old poults were divided into three groups. Group 1 received the herbal product in the feed six days before infection and in water three days before infection, then in feed and drinking water until the end of the experiment. Groups 2 and 3 were left untreated. At week 3 of age, Groups 1 and 2 were infected intracloacally with H. meleagridis. Three weeks after infection the surviving birds were euthanized and examined for pathological lesions. Mortality was 20% in Group 1 and 50% in Group 2. There were no deaths in Group 3. DNA of histomonads was detected in all examined caeca and livers of the dead birds, but was not detected in any examined organ of the surviving birds of all groups. There was no noticeable difference in the lesion scores of the dead birds between the groups. The surviving birds of all groups did not show lesions post mortem. Since all effective prophylactic and therapeutic drugs against histomoniasis were banned in the EU, under given conditions the investigated herbal product seems to be an effective alternative for the reduction of mortality in turkeys caused by histomoniasis.