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#1 Poultry Deseases » Les principales maladies des poules : symptômes, traitements et préven » 2020-04-19 20:29:09

Farmer
Replies: 0

Plusieurs maladies peuvent toucher les poules domestiques, les plus courantes étant la peste aviaire, les maladies de Marek et d'Aujeszky, la typhose, le coryza et la coccidiose. Comme tout animal, elles peuvent également être atteintes par des vers intestinaux et des parasites externes (poux, gale) pouvant être à l'origine de grave problèmes de santé.
Découvrez comment reconnaître ces maladies, les traiter et les anticiper notamment grâce à la vaccination et des règles d'hygiène essentielles.
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La maladie de Newcastle (peste aviaire)
Très contagieuse et foudroyante, les cas de survie sont rares et des séquelles sont souvent à craindre. La "peste aviaire" correspond à une septicémie brutale et incurable une fois contractée par un   symptômes sont une forte fièvre, un abattement, une déshydratation accompagnée de grande soif, une perte d'appétit. Les poules atteintes présentent souvent des plumes hérissées et des troubles respiratoires et nerveux. Contre cette maladie redoutable et mortelle, la mise en quarantaine des individus touchés est nécessaire pour protéger les autres de la   qu'aucun traitement curatif ne soit possible, un vaccin préventif existe heureusement contre la peste aviaire.
La maladie de Marek
Il s'agit d'une maladie du système digestif qui progresse par le développement de tumeurs sur certains organes. Une paralysie progressive s'opère au niveau des pattes et des ailes, la tête restant droite et rigide. Les poules atteintes deviennent aveugles et la mortalité est importante, surtout chez les jeunes adultes qui sont particulièrement exposées. Des difficultés respiratoires et des troubles digestifs peuvent s'ajouter aux symptômes. Un vaccin existe pour lutter contre la maladie de Marek, mais il n'est pas fiable à 100 % tandis qu'aucun traitement spécifique n'est possible. Causée par un herpès virus qui se transmet par voie respiratoire, la contagion est rapide et difficile à combattre.
La maladie d'Aujeszky
Cette maladie fatale ne peut pas non plus être soignée et nécessite de faire vacciner les poussins au plus vite. Les poules infestées doivent être abattues pour empêcher la contamination et leur éviter de nombreuses souffrances. Les symptômes sont des tremblements, de la somnolence, une baisse de l'appétit, une toux importante et des difficultés à respirer. Les poules atteintes présentent une crête et des barbillons bleuâtres. La maladie d'Aujeszky peut être évitée grâce à une vaccination efficace.
La typhose ou pullorose
La typhose, touchant les poules adultes, et la pullorose qui atteint les poussins se propagent plutôt dans les grands élevages. Elle se manifeste par une diarrhée verte chez la poule et jaune chez les petits, ainsi qu'une grande soif et une baisse de la ponte. Le traitement consiste à mélanger à l'eau du permanganate de potassium, ce qui permet généralement d'enrayer la propagation et de soigner une partie des volatiles atteints, bien que la mortalité reste élevée. Il s'agit de maladies infectieuses causées par des salmonelles, qui se transmettent de la poule au poussin et également par la litière, la nourriture et la boisson contaminées. Une hygiène rigoureuse est donc préconisée pour les éviter.
Le coryza des poules
Comme chez le chat, le coryza a pour symptômes une respiration difficile, des éternuements, des écoulements du nez et des yeux, des diarrhées et une perte de poids. Les yeux peuvent être gonflés avant de se fermer complètement et les poules atteintes secouent la tête pour libérer leurs narines. Le traitement consiste en l'administration d'antibiotiques et d'huile de foie de morue, un fortifiant naturel pouvant se donner par ailleurs en période de mue et d'attaques parasitaires. Un vaccin est également disponible, et fortement recommandé car le virus est contagieux et difficile à éradiquer.
La coccidiose, une maladie parasitaire
Cette maladie de l'intestin, causée par des protozoaires, correspond à une infestation parasitaire qui peut provoquer un éclatement de l'intestin grêle et un affaiblissement extrême de l'animal, dont les ressources nutritives (aliments et sels minéraux) sont exploitées par les parasites. Les os des poules malades sont fragilisés, ce qui cause chez ces dernières des douleurs aux membres. On observe une anémie chronique et des diarrhées sont possibles. Le recours à des antibiotiques et anti-coccidiens mélangés à la nourriture est un traitement généralement efficace si la maladie est détectée à temps.
Autres parasites internes et externes des poules
Les vers intestinaux, les poux et la gale sont autant de parasites susceptibles de fragiliser la santé des poules. On les trouve surtout dans les élevages de plein air car ils sont transmis par les insectes et l'environnement. Les ascaris et les vers sont des parasites internes qui puisent directement les nutriments dans les intestins des poules. On peut les éviter grâce à un vermifuge deux fois par an. Les poux, qui viennent se réfugier dans le plumage, peuvent être éradiqués au moyen d'une poudre insecticide appropriée.
La gale des pattes, un parasite microscopique de la famille des acariens, vient se nicher sous les écailles des pieds et laisse des croûtes blanches sur les pattes, qui peuvent aussi gonfler et se déformer. Il faut alors badigeonner les pattes de la poule avec du pétrole ou de la glycérine iodée. Sa cousine, la gale des plumes, se traite avec une poudre antiparasitaire et le poulailler doit être intégralement nettoyé et traité. D'ailleurs, la propreté et l'entretien régulier de l'environnement des poules permettra d'éviter bien des maladies et parasites ; il est aussi conseillé d'observer et de vérifier chaque jour leur état de santé, afin de détecter au plus vite les pathologies.

source: https://jardinage.lemonde.fr/dossier-19 … oules.html

#2 Chicken Farming » Insect meal: Good for bird and eggs » 2020-04-19 20:20:55

Farmer
Replies: 0

The animal feed sector is increasingly using alternative protein sources. In poultry, the use of insect meal to replace (part of the) soy in the diet looks promising. A few recent studies are presented here.

Insects, specifically black soldier fly larvae (BSFL), could be an ideal protein-rich alternative for soy, due to their high nutritional value and the low requirement for breeding space. BSFL are an excellent energy and protein source (37% to 65% protein) and it has been stated that their amino acid profile is more suitable for poultry (Barragan-Fonseca et al., 2017; Schiavone et al., 2017). However, BSFL contain chitin that can negatively affect protein digestibility and, therefore, can be detrimental to animal performance.

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BSFL is a highly performing feed ingredient alternative for poultry feed. Photo: Henk Riswick



Effect on growth performance
Several studies have been undertaken to determine whether BSFL is suitable as poultry feed ingredient and as alternative to soy. Dabbou and colleagues (2018) conducted a longitudinal study with dietary BSFL meal inclusion on broiler chicken growth performance, blood parameters, and intestinal morphology. In the study, 256 male broiler chickens were fed with four different inclusions of partially defatted BSFL meal from day 1 until day 35:
1. test diet with 0% BSFL meal inclusion,
2. with 5%,
3. with 10%, and
4. with 15% as substitute for soy (and corn gluten meal).
The diets were isonitrogenous and isoenergetic (same nitrogen and caloric content across diets). The results of this investigation suggest that inclusion of dietary BSFL meal up to 10% in male broiler chickens increase live weight and daily feed intake, however, only during the starter period (day 1 until day 10). During this period, the growth and development of chicken was much faster than in the subsequent periods (growing period from day 10 until day 24, and finisher period from day 24 until day 35). The increased feed intake and live weight gain was attributed to the improved diet   has already been reported that chicken seem to prefer feed that includes BSFL meal. During the growing and finisher period, the feed conversion ratio and live weight of the 15% BSFL group were negatively affected compared to 5% and 10% inclusion groups. It was hypothesised that the chitin content in the 15% BSFL meal diet could have negatively affected protein digestibility (Dabbou et al., 2018). In contrast, another study found that live weight and carcass weight of broiler chicken fed with 16% defatted BSFL meal inclusion were higher than the weights of control chicken after 34 days (BSFL substituted for soy). Here it was suggested that the higher amount of crude protein was most probably the cause and the chitin content, which did not seem to impact protein digestibility (Altmann et al., 2018).

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Chickens are allowed to eat live insects. The sector is waiting for approval of insect meal to be fed to poultry. Photo: Koos Groenewold

Broiler meat quality
Altmann and colleagues (2018) analysed the change of meat quality and sensory properties of breast fillet of broiler chicken packaged according to the current industrial packaging practices with highly oxygenated modified atmosphere packaging (HiOx MAP) over time. Breast fillets of broiler chicken that received defatted BSFL meal as replacement for 50% of the soy (total inclusion during starter period was 19.5% and during grower period 16%) seemed to have a more intense flavour when it was fresh compared to breast fillet of the control group (no dietary BSFL meal inclusion). The flavour intensity decreased 3 days after packaging and then again 7 days after packaging. The flavour intensity of breast fillet of the control group also decreased from 3 days after packaging, but, curiously, was found to be increased again after 7 days. No explanations for the continuously decreasing flavour intensity of breast fillet from the BSFL group were given. However, it was stated that less flavour intensity could be a selling point, as it is preferred by some consumers. Further analysis found more stable pH levels in breast fillet from the BSFL meal group from fresh until 7 days after packaging compared to breast fillet of the control group. It was hypothesised that BSFL inclusion could result in in longer shelf-life.

Effect on egg production
Dietary inclusion of defatted BSFL meal also impacts egg production. In an 8 week investigation in 108 individual 19 weeks old pullets (Shaver White) that were fed a standard corn–soybean meal diet, defatted BSFL meal was included as substitution for soybean at 5% and 7.5%. Here, corn was gradually increased with reduced soy content and increased BSFL content. However, the authors did not state the reason for these changes. This could have been done to meet the nutrient requirements for 19 weeks old pullets (according to Shaver White commercial management guidelines) and to create iso-caloric and iso-nitrogenous diets. Nevertheless, the results showed that defatted BSFL meal inclusion of 7.5% resulted in similar egg production, average egg weight, and egg quality parameters compared to the control diet (analysed at day 5 of weeks 22, 24, and 26). In contrast, 5% inclusion resulted in significant lower daily egg production. Egg weight and egg mass were also significantly lower than for eggs laid by control hens. The similar results between control and 7.5% BSFL inclusion group were attributed to the significantly increased feed intake of hens of the 7.5% BSFL inclusion group compared to the control and 5% BSFL inclusion group (Mwaniki et al., 2018). Mwaniki et al., 2018 showed that yolk colour, shell breaking strength, and shell thickness were significantly increased when BSFL were fed. The increase of these parameters could have been caused by increased calcium absorption and/or calcium metabolism in the gut of the hens.



Conclusion
Although results are partly inconsistent, it could be stated that dietary inclusion of defatted BSFL meal of 10% to 16% as soy replacement does not negatively affect the live weight and daily food intake of male broiler chicken, at least during the starter period. During the growing and finishing periods, lower levels have been recommended. The health status determined by blood marker analysis does not conclude detrimental effects of defatted BSFL (Dabbou et al., 2018; Altmann et al., 2018). For egg production, the dietary inclusion of 7.5% defatted BSFL meal as substitute for soy is reasonable and results into more uniform eggs with darker yolk that are more resistant and could result in less losses during the production and supply chain.
References are available on request.


source: https://www.poultryworld.net/Nutrition/ … s-451646E/

#3 Chicken Farming » Stressful birds more likely to produce female chicks ! » 2020-04-19 20:15:14

Farmer
Replies: 0

Stress and a lack of resources can trigger hormonal shifts that make it more likely for a mother to produce female offspring.


And research from the University of Georgia College of Agricultural and Environmental Sciences suggests that it’s also true for birds, although the mechanism is different.
Professor Kristen Navara argues that women who gain less weight during pregnancy are more likely to have female offspring, and wild birds that experience food shortages or other environmental stress produce more female chicks.
“So all birds and mammals produce these hormones, and that’s what elicits physiological responses that help them survive environmental challenges.
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Photo: Koos Groenewold


“When we knew that wild birds were able to adjust the sex of their offspring, our first question, was - what is responsible for transducing those environmental conditions into physiological signals that could control sex ratios?” The answer was stress hormones. We believed those stress hormones might mediate this effect on sex ratio, and we have found that they are, at least in part, a player in the process of manipulating sex ratios.”
They found that treating laying hens with corticosterone, the stress hormone, can influence the sex chromosome the hens’ offspring inherit.
Earlier this year, Prof Navara published a book exploring the factors that skew sex ratios in animals. The book, “Choosing Sexes: Mechanisms and Adaptive Patterns of Sex Allocation in Vertebrates,” is one of the only works that takes a comparative approach to explain the powerful use of hormones to manipulate sex ratios across species.
Understanding how stress hormones affect the sex of the hens’ chicks is invaluable information for the poultry industry, which needs male chickens to populate broiler houses and female chicks to populate laying houses.
“We know that birds in the wild have the ability to alter sex of their offspring without our help,” said Navara. “We want to harness that ability for the industry.
“In the poultry industry, the sex of the chicks is particularly important. So we’re trying to find a treatment that would programme the hen to produce more of the desired sex.”
Currently, with the help of the Georgia Genomics and Bioinformatics Core, Navara’s team has identified a handful of genes that could potentially be the links through which stress and stress hormones control the sex of progeny. They are now in the process of verifying whether expression of these genes does, in fact, change when stress triggers sex-ratio skews.
Up until this point, they’ve only been able to affect the sex ratio of the hen’s chicks by treating her with hormones, a practice that is banned in the poultry industry.
Their next step is finding a hormone-free treatment to trigger the gene responsible for translating stress into hormones to skew the sex ratio of chicks. Eventually, argues Navara, that could be accomplished through breeding, but that is one for the future.

Source: https://www.poultryworld.net/Health/Art … s-325762E/

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