Fifty years of anticoccidial vaccines for poultry (1952-2002)

Although earlier investigators experimented with anticoccidial vaccines, the world's first commercially successful product was developed by Prof S. A. Edgar of Auburn University, Auburn, AL. This product contained live, nonattenuated Eimeria tenella oocysts and was first marketed by Dorn and Mitchell, Inc., in 1952. Under the trade names of DM Cecal Coccidiosis Vaccine, Coxine, NObiCOX, and CocciVac, it went through several formulations containing various Eimeria species that parasitize chickens, and a further product containing turkey Eimeria species was also developed. After many product and company changes, one turkey and two chicken formulations of CocciVac are still marketed worldwide by Schering-Plough Animal Health, Inc. Chicken and turkey formulations of Immucox, a similar type of vaccine, were developed by Dr. E.-H. Lee and first marketed in 1985 in Canada by Vetech Laboratories, Inc. In 1974, Dr. T. K. Jeffers of Hess and Clark, Inc., Ashland, OH, published his discovery of precocious lines of coccidia, which facilitated the development of the first attenuated anticoccidial vaccine. For commercial reasons, Jeffers was unable to do this himself, but this first attenuated vaccine was designed by Dr. M. W. Shirley and colleagues at the Houghton Poultry Research Station (HPRS) in the United Kingdom. The vaccine was commercially developed under license in the United Kingdom by Glaxo Animal Health Ltd. and then Pitman-Moore, Inc., and launched in The Netherlands during 1989 under the trade name Paracox. After further changes in company ownership, two formulations for chickens are now marketed worldwide by Schering-Plough Animal Health, Inc. Attenuation of coccidia by embryo adaptation was reported in 1972 in the United Kingdom by Dr. P. L. Long, who originally worked at the HPRS and later became a professor at the University of Georgia, Athens, GA. An embryo-adapted line of E. tenella was included with precocious lines of other species in a series of three attenuated vaccines for chickens under the trade name Livacox, developed by Dr. P. Bedrník and launched in the Czech Republic in 1992 by Biopharm. The formulations of all other commercially available live anticoccidial vaccines for poultry are currently based upon the scientific principles established for the CocciVac, Paracox or Livacox vaccines.     

Results of salmonella isolation from poultry products, poultry, poultry environment, and other characteristics

Five hundred sixty-nine Salmonella were isolated out of 4745 samples from poultry products, poultry, and poultry environment in 1999 and 2000 from the Pacific northwest. These Salmonella were identified to their exact source, and some were serogrouped, serotyped, phage typed, and tested for antibiotic sensitivity. Food product samples tested included rinse water of spent hens and broilers and chicken ground meat. Poultry environment samples were hatchery fluff from the hatcheries where eggs of grandparent broiler breeders or parent broiler breeder eggs were hatched and drag swabs from poultry houses. Diagnostic samples were of liver or yolk sac contents collected at necropsy from the young chicks received in the laboratory. Of these samples tested, 569 were Salmonella positive (11.99%). Ninety-two Salmonella were serogrouped with polyvalent somatic antisera A-I and the polymerase chain reaction. Somatic serogroups B and C comprised 95.25% of all the Salmonella. Out of a total of 569 positive samples, 97 isolates of Salmonella were serotyped. A total of 16 serotypes and an unnamed Salmonella belonging to serogroup C1 were identified. The Salmonella serotypes were heidelberg (25.77%); kentucky (21.64%); montevideo (11.34%); hadar and enteritidis (5.15% each); infantis, typhimurium, ohio, and thompson (4.12% each); mbandaka and cerro (3.09% each); senftenberg (2.06%); berta, istanbul, indiana, and saintpaul (1.03% each); and an unnamed monomorphic Salmonella (2.06%). Ninety-two Salmonella were tested for drug sensitivity with nine different antimicrobials. All of the 92 Salmonella were resistant to erythromycin, lincomycin, and penicillin except one sample (S. berta), which was moderately sensitive to penicillin. All of the tested Salmonella were susceptible to sarafloxacin and ceftiofur. The percentages of Salmonella susceptible to sulfamethoxazole-trimethoprim, gentamicin, triple sulfa, and tetracycline were 97.83%, 92.39%, 86.96%, and 82.61%, respectively.     

Coccidiosis control with toltrazuril in conjunction with anticoccidial medicated or nonmedicated feed

A 42-day broiler floor pen study was conducted comparing the anticoccidial efficacy of toltrazuril (Baycox) as a stand alone treatment and as an additional treatment to in-feed anticoccidial programs. Toltrazuril was administered on days 18 and 19 in the drinking water at 7 mg/kg of body weight. The treatments were 125 ppm nicarbazin (days 0-14) to 66 ppm salinomycin (SAL) (days 15-35) with and without toltrazuril, SAL (days 0-35) with and without toltrazuril, nonmedicated (NM) to SAL with toltrazuril, and NM with and without toltrazuril. The controls were NM noninfected and infected. The treatments were replicated in five blocks of eight pens each in a randomized complete block design. All withdrawal feed was nonmedicated. On day 14, birds, except noninfected, were exposed to coccidial oocysts (Eimeria acervulina, Eimeria maxima, and Eimeria tenella) seeded litter. On days 21, 28, 35, and 42, birds and feed were weighed, four birds per pen were coccidial lesion scored, and litter oocyst counts were performed. The coccidial infection in the NM infected treatment caused a significant (P < 0.05) coccidiosis infection. Coccidiosis was moderately controlled in the anticoccidial treatment birds without toltrazuril. Performance in the NM with toltrazuril was equal to or better (P < 0.05) than the anticoccidial programs without toltrazuril. Toltrazuril was equal to the noninfected birds in performance. Toltrazuril most completely eliminated all coccidial lesions and dramatically reduced oocyst shedding. The performance data, lesion scores, and oocyst counts showed that a 2-day treatment with toltrazuril successfully controlled the coccidiosis with no relapse of infection. Toltrazuril can thus be used for supplemental control with in-feed anticoccidials or as a primary anticoccidial with nonmedicated feed.     

鸡球虫疫苗研究进展

鸡球虫病广泛分布于世界各地,是危害养鸡业的重要寄生虫疫病之一。本文对球虫抗原疫苗及其实验性免疫效果的近年研究进展和球虫疫苗的应用前景等进行较全面系统的阐述,为鸡球虫病的防治提供重要的参考依据。     

Backyard poultry: legislation,zoonoses and disease prevention

In law, backyard poultry are “food‐producing animals” and “farmed animals” and are subject to regulations regarding welfare, prescribing, banned procedures, disposal of carcases, feeding bans, notifiable diseases and disease surveillance in addition to those applying to most other pets. Many owners and some veterinary surgeons are unclear about the requirements of these regulations. Backyard poultry are also associated with some different zoonotic disease risks to mammalian pets. Because a high proportion of poultry morbidity and mortality relates to infectious diseases, the health of backyard poultry is amenable to improvement through basic husbandry, biosecurity, hygiene and preventive medicine measures that can be incorporated into a simple “flock‐health plan”. This article reviews these topics.     

Current state of poultry welfare: Progress,problems and strategies

This article supplements the published Proceedings of the 4th European Symposium on Poultry Welfare. It presents an overview of the conclusions of the Symposium and of the workshops and plenary discussions of the papers. The four main topics reviewed were: Basic Biology and Welfare, Welfare Criteria in Alternative Systems, Welfare of Turkeys, Waterfowl and Other Species, Welfare of Broilers.     

Necropsy of chickens, turkeys, and other poultry

Necropsy of dead or terminally ill birds is a key approach to disease diagnosis. It is important that one establish an orderly, consistent necropsy procedure and evaluate gross lesions as to their likely cause and significance. A very high percentage of farm flock poultry maladies can be diagnosed by gross lesions plus a few simple laboratory procedures, such as direct microscopy, Gram's stain, fecal flotation, and aerobic bacteriology.     

类胡萝卜素与畜禽产品着色

类胡萝卜素作为一种天然着色剂已经被广泛应用于畜牧生产中。本文简要阐述了类胡萝卜在动物机体内的分布及其着色机理，并对影响类胡萝卜着色的因素作一概述。     

Avian influenza vaccines and therapies for poultry

Vaccines have been used in avian influenza (AI) control programs to prevent, manage or eradicate AI from poultry and other birds. The best protection is produced from the humoral response against the hemagglutinin (HA) protein. A variety of vaccines have been developed and tested under experimental conditions with a few receiving licensure and field use following demonstration of purity, safety, efficacy and potency. Current licensed vaccines are predominately inactivated whole AI vaccines, typically produced from low pathogenicity (LP) AI virus strains, or occasionally from high pathogenicity AI virus strains. Recently, reverse genetic procedures have been developed that allow construction of vaccine strains using a genetically altered HA gene (changing HP HA proteolytic cleavage site to LP) and a backbone of internal gene segments for safe, high growth production. Other licensed AI vaccines include recombinant fowl poxvirus vector with an AI H5 insert and a recombinant Newcastle disease virus vector with an AI H5 gene insert. The latter vaccine can be mass administered via aerosol application.     

中东欧国家的禽肉、禽蛋生产及禽产品消费

欧盟委员会最近决定除保加利亚和罗马尼亚外,中东欧国家(CEEC)中其余八国将于2004年元月1日以整体形式加入欧盟,但这些国家还需进行必要的入盟谈判。     

我国禽流感等禽病防控六大新策略

近年来我国禽流感等禽病不仅导致巨额经济损失,而且对公共卫生构成严重威胁,受到全社会和全球广泛关注。本文首先分析我国养禽业基本现状和发展趋势、我国禽病防控困难所在,以及现有防控策略的不足,提出和分析六个禽病防控新策略：设立家禽防疫隔离带,即设立家禽限制养殖和加强检疫区,延缓疫情自然传播;加快小型养禽场退出速度,小型养禽场经济效益低,而疫情传播风险高,已是历史淘汰对象;禁止在开放的水体中饲养家禽,这类家禽易成为疫情超级传播者;推广电子活禽市场,它们不仅与其他网店相似,成本低而效益高,而且对公众的健康威胁小,禽病传播风险小;对无防疫合格证的养禽和屠宰加工场所进行适当的行政处罚,这是落实上述措施的合法途径;在境外为中国养禽,这与农业走出去和全球经济一体化发展趋势一致,能降低国内家禽饲养密度和禽病风险。     

SPF鸡群与疫苗生产

利用SPF鸡胚生产弱毒活疫苗，可以极大地提高疫苗的质量。采用SPF鸡胚，有利于人们认识病毒的复制规律，可以获得比普通鸡胚高得多的病毒滴度，进而获得可观的经济效金。加快技术市场化，对于已经实现GMP认证的企业采用SPF鸡胚制苗后是否仍能实现企业盈利，具有重要意义。     

Aflatoxin B1 in poultry: Toxicology, metabolism and prevention

Aflatoxins (AF) are ubiquitous in corn-based animal feed and causes hepatotoxic and hepatocarcinogenic effects. The most important AF in terms of toxic potency and occurrence is aflatoxin B₁ (AFB₁). Poultry, especially turkeys, are extremely sensitive to the toxic and carcinogenic action of AFB₁, resulting in millions of dollars in annual losses to producers due to reduced growth rate, increased susceptibility to disease, reduced egg production and other adverse effects. The extreme sensitivity of turkeys and other poultry to AFB₁ is associated with efficient hepatic cytochrome P450-mediated bioactivation and deficient detoxification by glutathione S-transferases (GST). Discerning the biochemical and molecular mechanisms of this extreme sensitivity of poultry to AFB₁, will contribute in the development of novel strategies to increase aflatoxin resistance. Since AFB₁ is an unavoidable contaminant of corn-based poultry feed, chemoprevention strategies aimed at reducing AFB₁ toxicity in poultry and in other animals have been the subject of numerous studies. This brief review summarizes many of the key recent findings regarding the action of aflatoxins in poultry.     

An overview of aflatoxicosis of poultry: Its characteristics,prevention and reduction

Aflatoxicosis represents one of the serous diseases of poultry, livestock and other animals. The cause of this disease in poultry and other food-producting animals has been attributed to the ingestion of various feeds contaminated with A. flavus. This toxigenic fungus is known to produce a group of extremely toxic metabolites, of which aflatoxin B₁ (AFB₁) is most potent. Avian species especially chickes, goslings, ducklings and turkey poults are most susceptible to AFB₁ toxicity. The toxic effects of AFB₁ are mainly localized in liver as manifested by hepatic necrosis, bile duct proliferation, icterus and hemorrhage. Chronic toxicity in those birds is characterized by loss of weight, decline in feed efficiency, drop in egg production and increased susceptibility to infections. The incidence of hepatocellular tumors, particularly in ducklings, is considered to be one of the serious consequences of aflatoxicosis. Even though prevention and avoidanve are the best way to control aflatoxicosis, natural contamination of crops with A. flavus is sometimes unavoidable. Such aflatoxin-contaminated feeds can be decontaminated using various methods which mainly focus on physical removal or chemical inactivation of the toxins in the feeds. Moreover, dietary additives such as activated charcoal, phenobarbital, cysteine, glutathione, betacarotene, fisetin and selenium have also been reported to be effective in the reduction of aflatoxicosis in poultry.