The effect of dietary supplementation with globin and spray-dried porcine plasma on performance, digestibility and histomorphological traits in broiler chickens.

This study evaluated the effects of globin and spray-dried porcine plasma (SDPP) on growth performance, digestibility, nitrogen retention, energy retention efficiency (ERE) and intestinal morphology of broiler chickens. A total of 336-day-old male broiler chickens were reared from 1 to 40 days of age and fed 3 diets (8 replicates/diet, 14 birds/replicate) during 3 feeding phases: starter (1-12 days), grower (12-25 days) and finisher (25-40 days). Isonitrogenous diets were formulated by replacing gluten protein isolate contained in the control diet (C diet) with 2% (starter) or 1% (grower and finisher) spray-dried porcine plasma in the plasma diet (SDPP diet). The globin diet (G diet) was obtained by adding globin on the top of C diet at a dose of 0.08% for the whole rearing period. Total tract apparent digestibility (aD), nitrogen retention and ERE were assessed during the three growing phases. At 12  and 40 days of age, one bird per pen was slaughtered to sample gut, liver, spleen and bursa of Fabricius for histomorphological investigations. The SDPP diet increased body weights of chickens at 12 (+60 g; p < .001), 25 (+101 g; p < .001) and 40 days (+130 g; p = .018) of age compared to C and G diets. Also SDPP improved crude protein aD (+9.7%) and ERE (+12.3%) during the starter phase (p < .001). Dietary globin and SDPP inclusion did not affect either the gut morphology or the histopathological findings in birds at 12 and 40 days of age, despite a numerical (+6.90% and +7.40% respectively) villus height improvement in the SDPP group. Overall, these results confirm that dietary supplementation with SDPP and, to a lesser extent, with globin can improve growth performance and dietary protein and energy utilization in broiler chickens without effect on gut functionality.

Pathways regulating equine skeletal muscle protein synthesis respond in a dose-dependent manner to graded levels of protein intake.

Activation of the mechanistic target of rapamycin (mTOR)-controlled anabolic signaling pathways in skeletal muscle of rodents and humans is responsive to the level of dietary protein supply, with maximal activation and rates of protein synthesis achieved with 0.2 to 0.4 g protein/kg body weight (BW). In horses, few data are available on the required level of dietary protein to maximize protein synthesis for maintenance and growth of skeletal muscle. To evaluate the effect of dietary protein level on muscle mTOR pathway activation, five mares received different amounts of a protein supplement that provided 0, 0.06, 0.125, 0.25, or 0.5 g of crude protein (CP)/kg BW per meal in a 5 × 5 Latin square design. On each sample day, horses were fasted overnight and were fed only their protein meal the following morning. A preprandial (0 min) and postprandial (90 min) blood sample was collected and a gluteus medius muscle sample was obtained 90 min after feeding the protein meal. Blood samples were analyzed for glucose, insulin, and amino acid concentrations. Activation of mTOR pathway components (mTOR and ribosomal protein S6 [rpS6]) in the muscle samples was measured by Western immunoblot analysis. Postprandial plasma glucose (P = 0.007) and insulin (P = 0.09) showed a quadratic increase, while total essential amino acid (P < 0.0001) concentrations increased linearly with the graded intake of the protein supplement. Activation of mTOR (P = 0.02) and its downstream target, rpS6 (P = 0.0008), increased quadratically and linearly in relation to the level of protein intake, respectively. Comparisons of individual doses showed no differences (P > 0.05) between the 0.25 and 0.5 g of protein intake for either mTOR or rpS6 activation, indicating that protein synthesis may have reached near maximal capacity around 0.25 g CP/kg BW. This is the first study to show that the activation of muscle protein synthetic pathways in horses is dose-dependent on the level of protein intake. Consumption of a moderate dose of high-quality protein resulted in near maximal muscle mTOR pathway activation in mature, sedentary horses.

Serologic screening for 13 infectious agents in roe deer (Capreolus capreolus) in Flanders.

INTRODUCTION: In order to investigate the role of roe deer in the maintenance and transmission of infectious animal and human diseases in Flanders, we conducted a serologic screening in 12 hunting areas. MATERIALS AND METHODS: Roe deer sera collected between 2008 and 2013 (n=190) were examined for antibodies against 13 infectious agents, using indirect enzyme-linked immunosorbent assay, virus neutralisation, immunofluorescence, or microagglutination test, depending on the agent. RESULTS AND DISCUSSION: High numbers of seropositives were found for Anaplasma phagocytophilum (45.8%), Toxoplasma gondii (43.2%) and Schmallenberg virus (27.9%), the latter with a distinct temporal distribution pattern following the outbreak in domestic ruminants. Lower antibody prevalence was found for Chlamydia abortus (6.7%), tick-borne encephalitis virus (5.1%), Neospora caninum (4.8%), and Mycobacterium avium subsp paratuberculosis (4.1%). The lowest prevalences were found for Leptospira (1.7%), bovine viral diarrhoea virus 1 (1.3%), and Coxiella burnetii (1.2%). No antibodies were found against Brucella sp., bovine herpesvirus 1, and bluetongue virus. A significant difference in seroprevalence between ages (higher in adults >1 year) was found for N. caninum. Four doubtful reacting sera accounted for a significant difference in seroprevalence between sexes for C. abortus (higher in females). CONCLUSIONS: Despite the more intensive landscape use in Flanders, the results are consistent with other European studies. Apart from maintaining C. abortus and MAP, roe deer do not seem to play an important role in the epidemiology of the examined zoonotic and domestic animal pathogens. Nevertheless, their meaning as sentinels should not be neglected in the absence of other wild cervid species.

Longitudinal monitoring for respiratory pathogens in broiler chickens reveals co-infection of Chlamydia psittaci and Ornithobacterium rhinotracheale.

Chlamydia psittaci is prevalent in broiler chicken production. However, the role of C. psittaci in the respiratory disease complex needs to be clarified. Our aim was to identify the time point when a C. psittaci infection appeared on a broiler farm and to examine the presence of other respiratory pathogens at that time. We focused on the 'major' respiratory pathogens occurring in Belgian broilers, namely infectious bronchitis virus (IBV), avian metapneumovirus (aMPV), Ornithobacterium rhinotracheale, Mycoplasma gallisepticum and Mycoplasma synoviae, and examined their co-occurrence with C. psittaci on three commercial broiler farms. For all farms, 1-day-old broilers showed high maternal antibody titres against C. psittaci in the presence of viable C. psittaci. Maternal antibodies seemed to protect against respiratory signs. Maternal antibodies declined and clinical outbreaks could be identified serologically even before maternal antibodies completely disappeared. Mixed infections with genotypes B/C and B/C/D were observed. Broilers with C. psittaci antibody increases showed conjunctivitis, signs of upper respiratory disease and dyspnoea. C. psittaci always preceded an O. rhinotracheale infection. Infections with aMPV, IBV or Mycoplasma spp. were not observed. Evidence was provided that C. psittaci could occur at an early age in broilers without a predisposing respiratory infection. Both C. psittaci and O. rhinotracheale should be considered when developing prevention strategies for respiratory disease in broilers.

Host-pathogen interactions in specific pathogen-free chickens following aerogenous infection with Chlamydia psittaci and Chlamydia abortus.

Although Chlamydia (C.) psittaci infections are recognized as an important factor causing economic losses and impairing animal welfare in poultry production, the specific mechanisms leading to severe clinical outcomes are poorly understood. In the present study, we comparatively investigated pathology and host immune response, as well as systemic dissemination and expression of essential chlamydial genes in the course of experimental aerogeneous infection with C. psittaci and the closely related C. abortus, respectively, in specific pathogen-free chicks. Clinical signs appeared sooner and were more severe in the C. psittaci-infected group. Compared to C. abortus infection, more intense systemic dissemination of C. psittaci correlated with higher and faster infiltration of immune cells, as well as more macroscopic lesions and epithelial pathology, such as hyperplasia and erosion. In thoracic air sac tissue, mRNA expression of immunologically relevant factors, such as IFN-γ, IL-1ß, IL-6, IL-17, IL-22, LITAF and iNOS was significantly stronger up-regulated in C. psittaci- than in C. abortus-infected birds between 3 and 14 days post-infection. Likewise, transcription rates of the chlamydial genes groEL, cpaf and ftsW were consistently higher in C. psittaci during the acute phase. These findings illustrate that the stronger replication of C. psittaci in its natural host also evoked a more intense immune response than in the case of C. abortus infection.

Emerging Chlamydia psittaci infections in chickens and examination of transmission to humans.

Chlamydia psittaci and atypical Chlamydiaceae infections are (re)-emerging in chickens. We therefore examined the prevalence of C. psittaci, atypical Chlamydiaceae and their zoonotic transmission on 19 Belgian chicken farms. Atypical Chlamydiaceae were not detected in chickens but 18 out of 19 farms were positive for C. psittaci by culture and PCR. C. psittaci ompA genotypes A and D were discovered. None of the examined humans (n = 31) was infected with atypical Chlamydiaceae, but 29 (93.5%) of them were positive for C. psittaci by culture and PCR. Genotypes A, D and a mixed infection with genotypes C and D were found. Humans (n = 2) working at the C. psittaci-negative farm never had respiratory complaints, while 25 out of 29 positive farmers (86.2%) reported yearly medical complaints potentially related to psittacosis. Four of them currently experienced respiratory disease and one of them was being treated with antibiotics. Four farmers (12.5%) mentioned that they had pneumonia after starting to keep chickens. Occupational physicians should be aware of emerging Chlamydiaceae infections in chickens.

Zoonotic infection with Chlamydia psittaci at an avian refuge centre.

This paper reports the zoonotic transmission of Chlamydia psittaci at a wild bird refuge centre resulting in the infection of members of the staff. Pharyngeal swabs were culture positive in 26% (11/42) of the sampled birds, and molecular characterisation of isolates revealed genotypes A, B, D, and E/B. The finding reflects multiple distinct infections and highlights the endemic nature of this pathogen in avian wildlife. Two clinically normal birds being prepared for release were found to be excreting C. psittaci genotype B or E/B and viable genotype B was detected in pharyngeal swabs from 30% (3/10) of the human workers tested. The findings suggest there should be enhanced surveillance and control measures in place in bird rehabilitation centres in order to minimise the risk of both zoonoses and of re-introduction of infection back into wildlife populations.

Animal models for studying female genital tract infection with Chlamydia trachomatis.

Chlamydia trachomatis is a Gram-negative obligate intracellular bacterial pathogen. It is the leading cause of bacterial sexually transmitted disease in the world, with more than 100 million new cases of genital tract infections with C. trachomatis occurring each year. Animal models are indispensable for the study of C. trachomatis infections and the development and evaluation of candidate vaccines. In this paper, the most commonly used animal models to study female genital tract infections with C. trachomatis will be reviewed, namely, the mouse, guinea pig, and nonhuman primate models. Additionally, we will focus on the more recently developed pig model.

Broiler ascites syndrome: collateral damage from efficient feed to meat conversion.

Chickens have been raised as food for human consumption for over 4000 years. Over this time they have been continuously selected for specific desirable characteristics by active selection of parents to produce birds which fit perceived needs. Despite this long history of selective breeding and improvements in rearing techniques, the efficiency with which broiler meat is produced has shown a remarkable leap in recent decades. Persistent selection for rapid growth, high feed utilisation efficiency and large cut yield has resulted in modern meat-type poultry lines with superior genetic potential with regard to productivity. However, mortality and the incidence of metabolic diseases has increased in parallel with growth rate. One such disease is broiler ascites syndrome, which has been shown to be closely associated with the fast growth and high meat yield resulting from intense selection and with modern rearing techniques. The review is focused on the historical background, pathogenesis, epidemiology and prevention of broiler ascites syndrome in modern broiler production.

Prevalence and genotype distribution of Chlamydia psittaci in feral Canada geese (Branta canadensis) in Belgium.

Chlamydia psittaci is a zoonotic pathogen with a wide range of avian hosts and worldwide geographical spread. Zoonotic transfer occurs by inhalation or direct contact and may cause psittacosis or parrot disease. Host reservoirs of particular epidemiological interest include gregarious or migratory species, as colonial behavior facilitates microbial spread amongst conspecifics and a migratory ecology permits disperse over a wide geographic region. The current study detected C. psittaci antibodies in 76 of 81 (93.8%) feral Canada geese (Branta canadensis) using a species-specific enzyme-linked immunosorbent assay. Viable C. psittaci were isolated from pharyngeal swabs of 47 of 81 (58%) birds, and subsequent ompA-based genotyping revealed genotypes E, B, and E/B. Absence of clinical symptoms in these geese could reflect a strong natural protection or a persistent infection. Canada geese are considered an important alien species in Europe. Current results denote that this avian reservoir poses a considerable risk to native wildlife as a potential source of C. psittaci.

Tetracycline-resistant Chlamydia suis in cases of reproductive failure on Belgian, Cypriote and Israeli pig production farms.

Similar cases of severe reproductive failure associated with the presence of Chlamydia suis in two Belgian, one Cypriote and one Israeli pig farrowing to slaughter farms are presented. Vaginal and rectal swabs from 39 sows were examined by culture and DNA microarray. Nineteen of 23 (83 %) C. suis-positive sows were infected with tetracycline-resistant C. suis strains, as determined by MIC tests. Furthermore, boar semen from a German artificial insemination centre, intended for export, was positive for C. suis. Emergence of tetracycline-resistant C. suis strains was confirmed.

Emerging Chlamydia psittaci infections in the chicken industry and pathology of Chlamydia psittaci genotype B and D strains in specific pathogen free chickens.

Sera of 30 Belgian and 10 Northern French chicken farms were tested by a Chlamydia (C.) psittaci major outer membrane protein (MOMP) based ELISA. Ninety-six percent, 93% and 90% of the Belgian broilers, broiler breeders and layers were seropositive. Ninety-one percent of the French broilers were seropositive. In addition, tissues of 5 Belgian and 5 French broiler farms were examined at slaughter. All French farms were culture positive while C. psittaci was cultured from the lungs of 80% of examined Belgian farms. C. psittaci infections are apparently emerging in chickens raised in Belgium and Northern France. We could proof Hill-Evans postulates for chicken-derived C. psittaci genotype B and D strains. Chicken-processing plant employees should be considered a risk group for human psittacosis. There is a need for higher awareness and for efficient risk assessment and management of C. psittaci infections in chickens as chlamydiosis in broilers seems to be underdiagnosed and infections with highly virulent strains do occur.

Pathogenicity of low and highly virulent Chlamydia psittaci isolates for specific-pathogen-free chickens.

In commercially raised poultry, chlamydiosis mostly seems to occur on turkey or duck farms, sometimes associated with zoonotic transmission and disease (psittacosis) in humans. However, Chlamydia infections are apparently emerging in chickens, and information on the virulence of Chlamydia in chickens is limited. Up-to-date Chlamydia psittaci genotypes B and D are most frequently found in broilers. We examined the pathogenicity of the well-characterized C. psittaci genotype B (CP3) and D (92/1293) strains in experimentally (aerosol) infected specific-pathogen-free chickens. Both strains caused conjunctivitis, rhinitis, and dyspnea. Pharyngeal and cloacal C. psittaci excretion was observed in all infected animals, indicative for systemic dissemination as proven by immunofluorescence staining of frozen tissue sections. Histopathologic lesions were present in all infected chickens. However, differences in pathology were observed. Genotype D led to mortality and more severe clinical signs and lesions as compared to genotype B, which showed lower virulence.

The effect of different working definitions on behavioral research involving stereotypies in Mongolian gerbils (Meriones unguiculatus).

Many sources of variation in animal experiments are related to characteristics of the animal or its husbandry conditions. In ethologic studies, observational methods can also affect interexperimental variation. Different descriptions for a behavior can lead to divergent findings that may be incorrectly attributed to other factors if not recognized as stemming from a classification dissonance. Here we discuss 2 observational studies in Mongolian gerbils (Meriones unguiculatus). The first study describes how data vary when 2 different working definitions are used for stereotypic digging: WD(mor), a definition based on a morphologic description of the behavior, and WD(12), a definition that relies mainly on a duration criterion of digging bouts (greater than 12 s). The total duration and number of stereotypic bouts were 22.0% and 63.1% lower, respectively, when WD(12) was applied compared with WD(mor). However, strong correlations existed between data generated by WD(mor) and WD(12), indicating that the 2 definitions yielded qualitatively similar results. The second study provides the first report that laboratory gerbils develop stereotypic behavior that is characterized by alternating bouts of digging and bar-gnawing. Of the 1685 stereotypy bouts investigated, 9.1% comprised both stereotypies, 87.6% consisted of digging only, and 3.3% consisted of bar gnawing only. Working definitions that neglect combined stereotypies can result in considerable underestimation of stereotypic behavior in Mongolian gerbils.

Tolerance and safety evaluation of N,N-dimethylglycine, a naturally occurring organic compound, as a feed additive in broiler diets.

N,N-Dimethylglycine (DMG) is a tertiary amino acid that naturally occurs as an intermediate metabolite in choline-to-glycine metabolism. The objective of the present trial was to evaluate tolerance, safety and bioaccumulation of dietary DMG in broilers when supplemented at 1 g and 10 g Na-DMG/kg. A feeding trial was conducted using 480 1-d-old broiler chicks that were randomly allocated to twenty-four pens and fed one of three test diets added with 0, 1 or 10 g Na-DMG/kg during a 39 d growth period. Production performance was recorded to assess tolerance and efficacy of the supplement. At the end of the trial, toxicity was evaluated by means of haematology, plasma biochemistry and histopathology of liver, kidney and heart (n 12), whereas bioaccumulation was assessed on breast meat, liver, blood, kidney and adipose tissue (n 8). Carcass traits were similar between the control and 1 g Na-DMG/kg feed groups (P>0·05), but the feed:gain ratio was significantly improved at 1 g Na-DMG/kg feed compared with the control or the 10-fold dose (P=0·008). Histological examinations showed no pathological effects and results of haematology and plasma biochemistry revealed similar values between the test groups (P>0·05). Bioaccumulation occurred at the 10-fold dose, but the resulting DMG content in breast meat was comparable with, for instance, wheat bran and much lower than uncooked spinach. In conclusion, DMG at 1 g Na-DMG/kg improved the feed:gain ratio in broilers without DMG being accumulated in consumer parts. Furthermore, dietary supplementation with DMG up to 10 g Na-DMG/kg did not induce toxicity or impaired performance in broilers.

Micromineral source affects intestinal morphology but not feather formation in pigeons.

During 7 weeks, two groups of eight pigeons received Zn, Cu, Mn and Se either as inorganic salts or organically bound to investigate the effect of micromineral source on two fast processes in avian metabolism: feather regrowth and intestinal renewal. Increased plasma Zn with reduced hepatic Cu in the organically bound minerals group suggests improved Zn bio-availability with a net antagonistic effect on Cu. Micromineral source did not affect feather regrowth, organ weight or intestinal pH, but the increased villus height with similar crypt depth pointed to increased absorptive surface.

Guidelines and ethical considerations for housing and management of psittacine birds used in research.

The Psittaciformes are a large order of landbirds comprising over 350 species in about 83 genera. In 2009, 141 published studies implicated parrots as research subjects; in 31 of these studies, 483 individuals from 45 different species could be considered laboratory animals. Amazons and budgerigars were by far the most represented psittacine species. The laboratory research topics were categorized as either veterinary medicine and diagnostics (bacteriology, hematology, morphology, and reproduction; 45%) or behavioral and sensory studies (behavior, acoustics, and vision; 17%). Confinement of psittacine species for research purposes is a matter of concern as scientifically based species-specific housing guidelines are scarce. The aim of this article is to provide scientific information relevant to the laboratory confinement of Psittaciformes to promote the refinement of acquisition, housing, and maintenance practices of these birds as laboratory animals. We briefly discuss systematics, geographical distribution, legislation, and conservation status as background information on laboratory parrot confinement. The following section presents welfare concerns related to captive containment (including domestication status) and psittacine cognition. We then discuss considerations in the acquisition of laboratory parrots and review important management issues such as nutrition, zoonoses, housing, and environmental enrichment. The final section reviews indications of distress and compromised welfare.

Psittacine birds as laboratory animals: refinements and assessment of welfare.

We address housing, refinements of husbandry, and some concerns regarding the use of parrots as laboratory animals. Because the duration of a project is most likely brief relative to the lifespan of the bird, among the most important goals is a well-established socialization program to maximize success of rehoming the birds after laboratory housing. We also present appropriate methods for catching and restraining parrots during experimental procedures. We discuss factors that contribute to appropriate laboratory and cage environments, such as the importance of cage location in the animal room as well as providing birds with suitable perching and enrichment devices. Finally, we review a few methods for scoring signs of compromised welfare in psittacine birds.