家禽胚蛋注射技术的应用研究(综述)——碳水化合物篇

在种蛋孵化后期,胚胎的组织器官快速发育,呼吸和破壳活动等都会消耗大量的能量,而种蛋储备的能量有限,这对雏鸡的出雏和早期发育很不利。胚蛋注射有可能通过增加能量供给量来提高雏鸡的质量。     

家禽胚蛋注射技术的应用研究(综述)——蛋白质、氨基酸和多肽篇

在孵化后期,入孵种蛋的胚胎发育迅速,营养供应紧张,通过胚蛋注射技术供应养分可能有利于胚胎的组织发育和雏鸡出壳后的早期生长。本文介绍了给入孵种蛋注射卵清蛋白、氨基酸和多肽后胚胎的发育及随后出壳雏禽的生长情况。     

家禽胚蛋注射技术的应用研究(综述)——益生菌和益生元篇

益生菌可以是一种活菌制剂,也可以是细菌的代谢产物,它可以通过改变或重建动物肠道微生物菌群的组成来提高宿主的健康水平。益生元是植物中不能被宿主(动物)体内的酶分解的非淀粉多糖,能通过选择性刺激动物肠道微生物菌群的生长与活性对宿主产生有益的影响,从而改善宿主的健康水平。益生菌和益生元已经在畜牧生产中得到广泛的应用,一般经口补给,而胚胎供应或将成为给家禽添加益生菌或益生元的新途径,扩展其在动物保健方面的新功能。     

家禽胚蛋注射技术的应用研究(综述)——概述篇

本文讨论了多种为提高家禽健康和生产性能对正在孵化的种蛋注射各种不同物质的禽胚注射法或胚蛋注射法,也称卵内注射法。家禽胚胎(又称禽胚或胚蛋)的羊膜已被证实是注射的有效部位,卵内注射通常在孵化的种蛋落盘时进行。注射物质所需的体积和剂量或浓度取决于家禽的种类、胚蛋的大小、注射的时机和部位、孵化系统、注射方式以及物质的类型。业已证明,人工注射或机械注射均能产生良好的效果。然而,商业应用要求注射方式实现自动化。本文所述的注射物质包括过去20年或更长时间内用于禽胚的疫苗、药物、激素、竞争性排斥培养物(competitiv exclusion cultures)、益生元和营养补充剂。被批准用于胚蛋接种的疫苗包括马立克氏病疫苗、传染性法氏囊病疫苗、禽痘苗、新城疫疫苗和球虫病疫苗,其中一些材料已被证明可作为提高家禽免疫力以及促进胚胎发育和雏鸡出雏后生长的有效备选材料。多篇论文指出,益生菌可有效预防家禽肠道感染细菌,而叶酸、卵清蛋白和多种氨基酸(包括L-精氨酸、L-赖氨酸、L-组氨酸、β-羟基-β-甲基丁酸和苏氨酸)的单独使用或联合使用已被证明能够有效促进家禽的胚胎发育或出壳后的生产性能。此外,胞嘧啶鸟嘌呤(Cytosine-phosphate-Guanine,CpG)寡聚脱氧核苷酸、维生素C、维生素E以及百里香和香芹也具有增强家禽免疫力的潜力,碳水化合物可用于提高家禽组织的糖原储备量,肌酸可以用于促进家禽肌肉的生长。微量元素和维生素D3可提高家禽的骨强度,而氯化钾可作为疫苗稀释液中的一种有效替代性电解质。这些物质和其他材料在胚蛋上的应用将会得到推广,并会给养禽业带来更多裨益。     

Ornithobacterium rhinotracheale infections in poultry: a review

O. rhinotracheale is a relatively new bacterium. It is found in commercial fowl and wild birds throughout the world. O. rhinotracheale causes respiratory disease, presenting as pneumonia and air sacculitis. It is transmitted horizontally as well as vertically. O. rhinotracheale is difficult to isolate. Serologically, twelve serotypes can be distinguished, of which serotype A is the most prevalent. Treatment can be difficult, because acquired resistance against the regular antibiotics is common in O. rhinotracheale isolates. An inactivated vaccine for broiler breeders has been developed and for turkeys an inactivated autovaccine can be made.     

The use of inulin in poultry feeding: a review

Since the European Union enforced the ban on antibiotic growth promoters in 2006, the research has been focused on natural feed additives which would have a proven positive impact on both production and animal health. Inulin is both the most commonly used and the most effective probiotic additive. The mechanism of inulin interactions with the avian body is complex, multidirectional and not fully understood. Despite a number of unresolved issues, many authors have demonstrated the positive impact of inulin on the host organism. Dietary supplementation of poultry feeding with inulin contributes to the modulation of intestinal microbiota through favouring a quick proliferation of beneficial Bifidobacterium and Lactobacillus strains and inhibiting the growth of pathogenic microbes. There are indications that inulin‐provoked changes in the host gut microbiota in poultry may alter the structure and histomorphology of the intestinal mucosa and improve its absorption capacity in poultry. It has also been demonstrated that inulin may affect the immune system and the systemic metabolism of minerals and lipids. The reports on inulin effects on the body and performance of poultry are often contradictory, as the effectiveness of this prebiotic is strongly dependent on the type and dose used, and the duration of its administration.     

Defence mechanisms against viral infection in poultry: a review

Defence against viral infections in poultry consists of innate and adaptive mechanisms. The innate defence is mainly formed by natural killer cells, granulocytes, and macrophages and their secreted products, such as nitric oxide and various cytokines. The innate defence is of crucial importance early in viral infections. Natural killer cell activity can be routinely determined in chickens of 4 weeks and older using the RP9 tumour cell line. In vitro assays to determine the phagocytosis and killing activity of granulocytes and macrophages towards bacteria have been developed for chickens, but they have not been used with respect to virally infected animals. Cytokines, such as interleukin (IL)-1, IL-6 and tumour necrosis factor (TNF)-alpha, are indicators of macrophage activity during viral infections, and assays to measure IL-1 and IL-6 have been applied to chicken-derived materials. The adaptive defence can be divided into humoral and cellular immunity and both take time to develop and thus are more important later on during viral infections. Various enzyme-linked immunosorbent assays (ELISAs) to measure humoral immunity specific for the viruses that most commonly infect poultry in the field are now commercially available. These ELISAs are based on a coating of a certain virus on the plate. After incubation with chicken sera, the bound virus-specific antibodies are recognized by conjugates specific for chicken IgM and IgG. Cytotoxic T lymphocyte activity can be measured using a recently developed in vitro assay based on reticuloendotheliosis virus-transformed target cells that are loaded with viral antigens, e.g. Newcastle disease virus. This assay is still in an experimental stage, but will offer great opportunities in the near future for research into the cellular defence mechanisms during viral infections.     

Blackhead disease (histomoniasis) in poultry: a critical review

After its discovery in 1893 in Rhode Island, blackhead disease was reported across the continent and soon in many other countries. It decimated the turkey industry in New England and followed production like a faithful shadow. Blackhead disease causes high mortality in turkeys, sometimes approaching 100% of a flock. In chickens, the mortality may be 10%-20% with high morbidity, although many outbreaks pass unnoticed. Early workers identified Histomonas meleagridis, a protozoan related to Entamoeba histolytica, Giardia lamblia, and Trichomonas, as the causative agent. Like many other parasites, its life cycle is complex, involving as an intermediate host, the common cecal worm Heterakis gallinarum. The necessity for bacteria for Histomonas to become virulent in the turkey and chicken, notably Escherichia coli, Bacillus subtilis, and Clostridium spp., was discovered by research in gnotobiotic birds. Changes in management brought the disease under control, although it remained the first cause of mortality in turkeys until modern antihistomonal products were developed after WWII. The ban of nitroimidazole products in the United States and Europe was followed by an upsurge in reported cases in turkeys and chickens. Immunization is not an option for prevention, as birds do not reliably become resistant to reinfection after suffering a primary exposure. Recent research demonstrated that histomoniasis could spread rapidly through a flock of turkeys by direct contact, probably involving the phenomenon of cloacal drinking. Direct transmission was not demonstrated for chickens, stressing dependence on H. gallinarum as the source of infection. The lack of suitable treatment drugs or vaccines emphasizes the importance of prevention by worm control and management.     

Gastric rupture in horses: a review of 54 cases

The historical, clinical, laboratory, surgical and necropsy findings in 54 cases of gastric rupture in horses are described. Eleven per cent of the deaths of horses undergoing exploratory coeliotomy for colic during the period of the study were a result of gastric rupture. Comparison with all horses which had exploratory coeliotomies for colic over an eight year period did not show that horses with gastric rupture were different from these reference horses regarding age, breed or season. There were fewer stallions than expected in the gastric rupture group. Horses with histories of both acute and chronic (more than 36 h) colic were susceptible to gastric rupture. Primary and idiopathic causes of gastric dilation and rupture accounted for about one-third of the horses. All but one of these cases resulting from secondary causes fell into three aetiologically-related groups: obstructive, peritoneal and enteric, with approximately equal numbers of horses in each group. Most of the ruptures occurred along the greater curvature of the stomach. At least six horses ruptured their stomachs postoperatively in the presence of an indwelling nasogastric tube. The presence or absence of gastric reflux following nasogastric intubation was not a reliable indicator, on its own, of gastric dilation. Horses that later died from gastric rupture had markedly elevated heart rate, hypochloraemia, peritoneal exudative effusion (particularly with evidence of sepsis), pre- and/or postoperative gastric reflux and small or large intestinal disease. However, no distinctive feature of these horses was shown to place them at risk of gastric rupture.     

家禽胚蛋注射技术的应用研究(综述)——疫苗篇

雏鸡出壳时要面对多种应激因素,此时机体的免疫状况对它的存活和抗病能力有重要的影响。众多研究表明,胚蛋注射(又称卵内注射)疫苗可以高效率、低成本和有效地诱导入孵种蛋的胚胎产生免疫应答反应,从而增强雏鸡出壳后抗感染的能力。本文将介绍当前胚蛋注射不同疫苗的应用和研究情况。     

家禽胚蛋注射技术的应用研究(综述)——激素篇

本文讨论了给入孵种蛋的胚胎注射睾酮、促甲状腺激素释放激素、甲状腺素、促肾上腺皮质素释放激素、生长激素和胰岛素样生长因子对家禽胚胎出壳后生长性能的影响。     

The relevance of glycine and serine in poultry nutrition: a review

ABSTRACT

1. Dietary glycine equivalents (Gly_equi) for glycine and serine represent the first-limiting non-essential amino acid in poultry diets. Targeted adjustment of essential amino acids and Gly_equi in diets can considerably decrease crude protein (CP) in poultry diets below the limit of CP reduction when only essential amino acids are adjusted.

2. The level to which CP can be reduced in diets adequate in Gly_equi depends on the objective; which includes reducing dietary CP without affecting performance and increasing nitrogen utilisation efficiency. Dietary CP can be reduced to ~15–16% in diets for up to 21 d old broiler chicken without affecting growth performance compared to responses to diets with currently common CP concentrations by considering Gly_equi in the diet formulation. Dietary CP can be further reduced to maximise nitrogen utilisation efficiency; however, this leads to reduced growth performance.

3. The dietary Gly_equi requirement of poultry varies depending on other dietary constituents. In broiler chickens up to 21 days of age, the dietary Gly_equi requirement is estimated to be between 11 and 20 g/kg. This estimate is influenced by the concentrations of Cys and the endogenous Gly_equi precursors, threonine and choline. Urinary nitrogen excretion seems to be a major determinant of the response to dietary Gly_equi, because it is needed for uric acid formation.

4. The variable requirement for dietary Gly_equi means that its static recommendation in poultry diets would lead to high safety margins in Gly_equi supply or the risk of Gly_equi deficiency. Variable recommendations for dietary Gly_equi concentrations would help to supply birds based on their specific requirements and could reduce nitrogen emissions originating from poultry farming.     

Reconsidering betaine as a natural anti-heat stress agent in poultry industry: a review

Betaine is found ubiquitously in plants, animals, microorganisms, and rich dietary sources including seafood, spinach, and wheat bran. The chief physiological role of betaine is to function as a methyl donor and an osmolyte. Betaine also acts as an osmolyte, to maintain the avian’s cellular water and ion balance to improve the avian’s capacity against heat stress via preventing dehydration and osmotic inactivation. It helps in maintaining the protective osmolytic activity, especially in heat-stressed birds. Betaine may promote various intestinal microbes against osmotic variations and thus improve microbial fermentation activity. Previous studies showed that dietary supplementation of betaine in poultry diets could positively affect nutrients’ digestibility, reduce abdominal fat weight, and increase breast meat yield. In addition, betaine has been reported to protect internal organs and boost their performance. Its inclusion in poultry diet is sparing essential amino acids like choline and methionine. In addition, it may play an important role in lean meat production by positively affecting the lipid metabolism with increased fatty acids catabolism and thus reducing carcass fat deposition. The aim of this review article was to broaden the knowledge regarding betaine and its importance in the poultry industry to cope with the heat stress problem. Moreover, it should be added to the diet as a natural anti-stressor through different routes (water/feed) to overcome the heat stress problem. However, further studies need to be conducted at the genetic and molecular basis to elucidate the mechanism behind the betaine as a natural anti-heat agent to decrease the heat stress problem in the poultry industry.     

The role of rodents in avian influenza outbreaks in poultry farms: a review

Wild migratory birds are associated with global avian influenza virus (AIV) spread. Although direct contact with wild birds and contaminated fomites is unlikely in modern non-free range poultry farms applying biosecurity measures, AIV outbreaks still occur. This suggests involvement of other intermediate factors for virus transmission between wild birds and poultry. This review describes current evidence of the potential role of rodents in AIV transmission from wild birds to poultry and between poultry houses. Rodents can be abundant around poultry houses, share their habitat with waterfowl and can readily enter poultry houses. Survival of AIV from waterfowl in poultry house surroundings and on the coat of rodents suggests that rodents are likely to act as mechanical vector. AIVs can replicate in rodents without adaptation, resulting in high viral titres in lungs and nasal turbinates, virus presence in nasal washes and saliva, and transmission to naïve contact animals. Therefore, active AIV shedding by infected rodents may play a role in transmission to poultry. Further field and experimental studies are needed to provide evidence for a role of rodents in AIV epidemiology. Making poultry houses rodent-proof and the immediate surroundings unattractive for rodents are recommended as preventive measures against possible AIV introduction.     

Phenolic compounds as natural feed additives in poultry and swine diets: a review

Due to ban on using antibiotics in feed industry, awareness of using natural feed additives have led to a great demand. The interest of plants phenolic compounds as a potential natural antioxidant source has been considered in research community due to their predictable potential role as feed additives in poultry and swine production.However, the mode of action for their functional role and dosage recommendation in animal diets are still remain indistinct. Taking into account, the present review study highlights an outline about the mode of action of phenolic compound and their experimental uses in poultry and swine focusing on the growth performance, antioxidant function, immune function, antimicrobial role and overall health status, justified with the past findings till to date.Finally, the present review study concluded that supplementation of phenolic compounds as natural feed additives may have a role on the antioxidant, immunity, antimicrobial and overall production performance in poultry and swine.     

Application of encapsulated nano materials as feed additive in livestock and poultry: a review

Veterinary Research Communications - Livestock plays a significant role in the socio-economic development of developing countries by providing livelihood and nutritional security, transport,...     

The insensitive mechanism of poultry to zearalenone: A review

Zearalenone (ZEN) is one of the most common contaminating mycotoxins and is mainly produced by Fusarium graminearum. ZEN and its metabolites can interfere with estrogen function and affect animals' reproductive ability. Pigs are most susceptible to ZEN, and ZEN is less harmful to poultry than to pigs. The exact mechanism for the difference in susceptibility remains unclear. In this review, we summarized some possible reasons for the relative insensitivity of poultry to ZEN, such as the lower total amount of α-zearalenol (α-ZOL) and the α-ZOL-to-β-ZOL ratio which reduce the toxicity of ZEN to poultry. The faster hepatic and enteric circulation, and excretion capacity in poultry can excrete more ZEN and its metabolites. There are other possible factors such as the transformation of intestinal microorganisms, differences in hydroxysteroid dehydrogenases' activity, high estrogen levels, and low estrogen receptors affinity which can also cause poultry to be relatively insensitive to ZEN. In this review, we summarized the hazards, pollution status, metabolic pathways, and some measures to mitigate ZEN's harmfulness. Specifically, we discussed the possible mechanisms of low reproductive toxicity by ZEN in poultry.