Past, present and future of poultry diseases control

La demande sur les protéines d’origine animale et en particulier sur les produits avicoles est de plus en plus importante, et il en résulte un besoin de plus en plus impérieux d’intensification de la production ce qui représente un facteur d’augmentation des risques sanitaires. En même temps les lobbies de consommateurs ont augmenté leurs niveaux d’exigences en matière de qualité des produits refusant légitimement les résidus de substances chimiques, de médicaments, la présence de germes zoonotiques et se préoccupant de plus en plus d’environnement et de bien-être animal. Les stratégies de contrôle des maladies, mises au service de ces productions ont connu beaucoup de développements, avec de la biosécurité, des plans d’éradication, et des programmes de vaccination de plus en plus élaborés avec des vaccins classiques « vivants » ou « inactivés », évoluant à la demande des utilisateurs vers des vaccins plus faciles à utiliser et plus efficaces. C’est ainsi que sont apparus des vaccins fruits de travaux de génie génétique assurant une bonne protection, sans réactions post vaccinales, et sans pouvoir de dissémination, utilisés de plus en plus tôt dans la vie de l’animal. Les futures voies de production de vaccins dits de troisième génération sont représentées par les vaccins à ADN et les vaccins produits sur plantes très prometteurs. La disponibilité et le succès de ces nouvelles générations de vaccins vont dépendre des moyens consacrés à la recherche, de la pertinence et de l’adaptation aux différents marchés et de leur attractivité, cela va dépendre enfin de la liberté d’opérer qui peut être limité par de nouvelles contraintes comme les brevets sur le vivant.The demand for animal protein and in particular for poultry products is becoming more and more important, and the result is a growing need for intensification of production, which represents a risk-increasing health factor. At the same time consumer lobbies have increased their levels of product quality requirements legitimately refusing residues of chemical substances, drugs, the presence of zoonotic germs and worrying more and more about the environment and animal well-being. Disease control strategies at the service of these productions have undergone many developments, including biosecurity, eradication plans, and increasingly elaborate vaccination programs with traditional “live” or “inactivated” vaccines. “, Evolving at the request of users to vaccines easier to use and more effective. This is how vaccines have emerged from genetic engineering works providing good protection, without post-vaccine reactions, and without the ability to spread, used earlier in the animal’s life. Future production routes for so-called third-generation vaccines are represented by DNA vaccines and vaccines produced on plants. The availability and success of these new generations of vaccines will depend on the resources devoted to research, the relevance and adaptation to different markets and their attractiveness, it will depend finally on the freedom to operate which can be limited by new constraints such as patents on the living

Étude lésionnelle et bactériologique des infections du sac vitellin (omphalites) chez les poussins chair, Nord-Est de la Tunisie

The present study was carried out for three objectives: firstly, to investigate the prevalence of the yolk sac infections in broilers in the northeast of Tunisia. The second goal was to know the main germs responsible for this problem. Finally, we aimed to study the sensitivity of isolated bacteria to the main antibiotics used in the field. A total of 170 chicks (3 to 8 days) were necropsied. Suspected yolk sacs were collected using sterile swabs and sent to the laboratory for bacteriological analysis and antibiogram. Overall prevalence of 55.3% (94 chicks) was assessed. Statistically significant difference was noted among the different age groups, with highly prevalence observed in 5 days old animals (76%). Bacteriological analysis revealed that 71.3% (67 chicks) showed single bacterial infection. E. coli was the most important isolated bacteria (74.5%), followed by Klebsiella spp. (31.9%), Salmonella spp. (10.6%), Proteus spp. (9.6%) and Staphylococcus aureus (2.1%). A high correlation was noted between the chick mortality and infection by E. coli, Klebsiella and Proteus. Tested bacteria isolates (109 isolates) to twelve antibiotic agents showed high sensitivity to streptomycin, colistin, amoxicillin and amoxicillin-clavulanic-acid. A higher resistance was noted to enrofloxacin. Multidrug resistant isolates were detected in 38 (34.9%) bacteria isolates. Keywords: Yolk sac infection, Bacteriology, Multidrug resistance, Broiler, TunisiaLa présente étude a un triple objectif: d’abord pour estimer la prévalence de l’infection du sac vitellin chez le poulet de chair dans les élevages du Nord-Est de la Tunisie. Le second objectif est d’identifier les principales bactéries responsables de ce problème. Enfin, nous visons l’étude de la sensibilité des souches isolées vis-à-vis des principales molécules d’antibiotiques utilisées sur le terrain.  Un total de 170 poussins (3-8 jours d’âge) est autopsié. Les sacs vitellins suspects sont prélevés moyennant des écouvillons stériles envoyés au laboratoire en vue des analyses bactériologiques et des antibiogrammes. La prévalence globale des omphalites est de 55,3% (94 poussins). Une différence statistiquement significative est notée selon les tranches d’âge, avec une plus grande prévalence observée chez les oiseaux âgés de 5 jours (76%). Les analyses bactériologiques ont révélé que 71,3% (67 poussins) des animaux montraient une infection bactérienne unique. E. coli est la bactérie la plus isolées (74,5%), suivie de Klebsiella spp. (31,9%), Salmonella spp. (10,6%), Proteus spp. (9,6%) et Staphylococcus aureus (2,1%). Une corrélation élevée est notée entre la mortalité des poussins et l’infection par E. coli, Klebsiella et Proteus. Les isolats testés (109 isolats) vis-à-vis de 12 antibiotiques montrent une sensibilité importante à la streptomycine, la colistine, l’amoxicilline et l’amoxicilline-acide clavulanique. Une résistance élevée est notée vis-à-vis de l’enrofloxacine. Une multi-résistance est détectée chez 38 souches (34,9%) isolées. Mots clefs: Infection du sac vitellin, Bactériologie, Multi-résistance aux antibiotiques, poulet de chair, Tunisi

Kinetics of maternal antibodies against low pathogenic avian influenza virus H9N2 and interference with vaccination in broiler chickens

La vaccination systématique des reproducteurs contre l’IAFP H9N2 permet la transmission d’une immunité passive à leur descendance. Cependant, les anticorps maternels anti-H9N2 présents chez les jeunes poussins à l’éclosion, leurs offrent une certaine protection pendant les premiers jours d’âge et peuvent de même provoquer une interférence avec la vaccination. Le but de cette étude est d'évaluer la cinétique des AOMs en présence et/ou en absence de vaccination. Dans la première partie, nous avons suivi la cinétique des anticorps anti-H9N2 chez des poussins non vaccinés élevés en isolement. Dans la deuxième partie, des lots de poulets de chair vaccinés avec 4 différents vaccins, administrés à 3 différents âges, répartis dans  plusieurs régions du Maroc ont fait l’objet d’un suivi sérologique, sur l’ensemble des résultats obtenus, un effet âge de vaccination a été prouvé par analyse statistique ce qui met en cause une interférence entre les vaccins anti-IAFP H9N2 et les anticorps d’origine maternelles. Mots clés: Influenza aviaire faiblement pathogène H9N2 (IAFP H9N2), Anticorps d’origine maternelle (AOM), ELISA, IHA, Temps de demi-vieSystematic vaccination of Breeders against AILP H9N2 allows the transmission of passive immunity to their progeniture. However, the maternal anti-H9N2 antibodies present in day old chicks offer them some protection during the first days of age and may interfere with vaccination. The aim of this study is to assess the kinetics of AOMs in the presence and/or in the absence of vaccination. In the first part, we followed the kinetics of anti-H9N2 antibodies in unvaccinated chicks reared in isolation. In the second part, batches of broilers vaccinated with 4 different vaccines, administered at 3 different ages, distributed in several regions of Morocco were the subject of serological monitoring, on all the results obtained, an effect Age of vaccination has been proven by statistical analysis which calls into question the interference between H9N2 anti-IAFP vaccines and maternal antibodies. Keywords: Low pathogenic avian influenza H9N2 (IAFP H9N2), Maternal antibody, ELISA, HI, Half-lif

Les variants du virus de la bronchite infectieuse aviaire en Tunisie : incidence, typage

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Les coronaviroses aviaires

Coronaviruses are RNA viruses classified into Alphacoronavirus, Betacoronavirus, Gammacoronavirus and Deltacoronavirus. These viruses seem to come from bats, and more particularly Alphacoronaviruses and Betacoronaviruses (the genus where zoonoses are observed), while birds are the source of Gammacoronaviruses and Deltacoronaviruses. The first coronavirus identified was that of avian infectious bronchitis in 1931 in the United States. Other coronaviruses have been identified in birds, similar to or different from the IB virus of avian infectious bronchitis and are responsible for turkey enteritis (TCoV) and fulminating guinea fowl disease (GfCoV). Finally, a deltacoronavirus can be found in both pigs (PD CoV UKU15) and birds (PRCV).Les coronavirus sont des virus à ARN classés en Alphacoronavirus, Betacoronavirus, Gammacoronavirus et Deltacoronavirus. Ces virus semblent provenir des chauves-souris, et plus particulièrement les Alphacoronavirus et les Betacoronavirus (genre où l’on observe des zoonoses) alors que les oiseaux seraient à l’origine des Gammacoronavirus et des Deltacoronavirus. Le premier coronavirus identifié fut celui de la bronchite infectieuse aviaire en 1931 aux États-Unis. D’autres coronavirus ont été identifiés chez les oiseaux, proches ou différents du virus BI de la bronchite infectieuse aviaire et sont responsables de l’entérite de la dinde (TCoV) et de la maladie foudroyante de la pintade (GfCoV). Enfin, un deltacoronavirus peut être rencontré à la fois chez le porc (PD CoV UKU15) et les oiseaux.Brugères Jeanne, Bouzouaia Moncef. Les coronaviroses aviaires. In: Bulletin de l'Académie Vétérinaire de France tome 174, 2021. pp. 95-101

Interactions between egg storage duration and breeder age on selected egg quality, hatching results, and chicken quality

Egg storage duration and breeder age are probably interacting to influence egg quality, hatchability, and hatchling quality. To evaluate this interaction, the impact of breeder age (31, 42, 66 weeks) and storage duration (2, 5, 12, 19 days) was investigated on broiler breeder eggs (Arbor Acres). Thick albumen diameter and pH increased, and yolk dry matter decreased between 2 and 19 days of storage. With the increase of breeder age from 31 to 66 weeks, albumen height, percentage and dry matter and shell percentage decreased and the egg weight and yolk percentage, dry matter and diameter increased. Prolonged egg storage increased the yolk pH in all breeder ages, but earlier and steeper in the oldest breeders. Prolonged egg storage resulted in a lower hatchability of set and fertile eggs due to a higher percentage of embryonic mortality. Early mortality increased earlier and steeper with prolonged egg storage in the oldest compared to younger breeders. Between 5 and 19 days of storage, yolk free body mass, liver and proventriculus + gizzard percentages decreased, as well as hatchling length and yolk efficiency (yolk absorption per initial yolk weight). The latter effects were most pronounced in the younger than in the older breeders. Therefore, eggs are preferably stored shorter than 7 d, but if long storage (≥12 days) cannot be avoided, we recommend to store eggs of older breeders when egg quality and hatchability are most important. In case hatchling quality is most important, it would be better to store eggs of younger breeders (31 weeks) for a prolonged period.</p

Interactions between egg storage duration and broiler breeder age on egg fat content, chicken organ weights, and growth performance

Egg storage and breeder age are between the most important factors affecting egg lipids, chicken quality, and posthatch performance. To evaluate these factors, including their interaction, the impact of egg storage duration (5, 12, and 19 D), and breeder age (47 and 67 wk) was investigated in Arbor Acres broiler eggs and chickens. Total yolk fat content, chicken organ development at hatch and at 6 D of age, and posthatch performance (at 7 D and 35 D of age) were determined. Total fat content in fresh yolk was lower in 12 and 19 D stored eggs than in 5 D stored eggs (Δ = −2.42% on average). In hatchlings, the heart percentage was not affected by storage duration in the younger flock but was higher after 19 D than after 5 and 12 D of storage in the old flock (Δ = +0.09% on average). Residual yolk weight was higher after 12 D egg storage than after 5 D egg storage (Δ = +1.7 g), with 19 D egg storage in between. Liver and intestine percentage decreased with storage duration. Residual yolk weight (Δ = +1.09 g) and liver percentage (Δ = +0.18%) were higher in old breeders than in younger breeders. At day 6, chicken BW, yolk free body mass, liver percentage, and intestine percentage interacted between egg storage duration and breeder age with the strongest effects in chickens from older breeder after 19 D of storage. Heart percentage was lower after 19 D compared with 5 and 12 D of storage (Δ = −0.05% on average). Feed intake and feed conversion ratio were higher between day 0 to 7 and 0 to 35 after 19 D than after 5 D egg storage (Δ19-5 D = +12 g and +199 g; +0.11 points and +0.09 points, respectively). It can be concluded that when it is needed, eggs from younger breeders should be stored for a prolonged period (≥12 D) rather than those from older breeders.</p

Egg storage and breeder age impact on egg quality and embryo development

Prolonged hatching egg storage (>7 days) influences internal egg quality and embryo survival during both storage and subsequent incubation. Moreover, effects of storage of hatching eggs interact with the breeder age. The aim of this review was to investigate how this interaction between storage duration and breeder age affects egg, embryo, hatchling and chicken characteristics. Prolonged storage resulted in a reduction in egg quality in both young and old breeders. This reduction was more pronounced in young flocks than in older flocks. For example, albumen pH increased more after 8 days of storage in younger flocks than in older flocks. Additionally, the embryonic morphological stage appears to increase as well with storage duration, but this increase is again more pronounced in younger flocks than in older flocks. Short storage (7 days) resulted in a decline in hatchability, which was stronger in older breeders than in younger breeders. Prolonged storage duration resulted in lower chicken quality in both young and old breeders, but interaction between storage duration and breeder age on multiple chicken quality parameters is not clear. Based on this review, it can be concluded that (a) Short storage can improve hatchability of eggs from young breeders, but not from older breeders. (b) Negative impact of long storage appears to be lower with young breeders than with old breeders. (c) Adapted storage conditions related to the age of breeders might be an option to reduce negative effects of prolonged storage on hatching egg quality and chicken quality.</p