eChapters

IBD is an acute, contagious, viral disease of young chickens characterized by diarrhoea, vent pecking, trembling, incoordination, inflammation followed by atrophy of the bursa of Fabricius (BF) and by a variable degree of immunosuppression.

In the USA the disease was reported in Gumboro, Delaware in 1962, hence the name. The occurrence is worldwide.

Marek’s disease is a herpesvirus-induced neoplastic disease of chickens characterized by infiltration of various nerve trunks and/or organs with pleomorphic lymphoid cells. Marek’s disease is world wide in distribution. Marek’s Disease has been named after Josef Marek who published the disease in 4 roosters in 1907.

Occurrence

In chickens only, however turkeys and quail have limited susceptibility. Lesions similar to MD have been seen in pheasants, ducks, pigeons, geese, canaries, budgerigars, swans and great horned owls. However, aetiology for lesions in these species has not been proved. It may appear at 3-4 weeks but usually after eight weeks, with major losses from 12-25 weeks. Morbidity and mortality varies depending on the virulence of MDV.

LL is a retrovirus-causes, neoplastic disease of semi-mature or mature chickens characterized by a gradual onset in a flock, persistent low mortality and neoplasia of, the bursa of Fabricius (BF) with metastasis to many other internal organs especially the liver, spleen and kidney.

The neoplastic disease primarily of broiler breeders and broilers causing serious economic losses in the commercial poultry industry. A case has been recorded in a budgerigar.

Etiology

ALV-J subgroup, identified in 1988. It became widespread in commercial meat type poultry in the 1990’s. Transmission of ALV-J is much higher than other subgroups thus making control much more difficult.

Term endotheliosis designates a variety of syndrome caused by a reticuloendothelial virus (REV). REV caused syndromes have been demonstrated world wide.

Etiology

Based on replication of the virus in chicken fibroblast cell culture, two strains are known: replication defective T strain and the non-defective A strain. The REV manifests three distinct diseases syndromes:

Etiology

Avian Nephritis Virus (ANV), an RNA virus is Astro virus under the genus Avastrovirus in Astroviridae family. Strains of ANV exist. ANV is very resistant and stable in the environment.

AI is a viral disease affecting the respiratory, enteric or nervous system of many kinds of birds. The most virulent form is an acute, generalized disease characterized in poultry by a short course and extremely high mortality.

(AE; Epidemic Tremor; Infectious Avian Encephalomyelitis)

AE is a viral infection of chickens, turkeys, pheasants and cortunix quail characterized in young birds by ataxia progressing to paralysis and, usually, by tremors of the head and neck. Infected adults usually show no signs. AE is world wide in distribution.

Etiology

A turkey coronavirus (TCV).

Hosts

Turkeys of all ages, but the disease is mostly observed in young turkeys (first few weeks old).

It is an acute disease of turkeys, occurring in 6-7 wk. -Old turkeys, but has been seen in younger and older turkeys as well. The disease is worldwide in distribution.

Etiological Agent

It belongs to adenovirus type II. A serologically indistinguishable virus from HE virus, causes marble spleen disease (MSD) in confinement reared pheasants (3-8 months old). The disease shows predominantly respiratory signs. A virus of the same group causes avian adenovirus group II splenomegaly (AAS) in chickens.

Etiology Herpes Virus

Variation in pathogenicity of virus strains has been reported, but all strains appear identical immunologically.

Occurrence

The disease was first reported in the Netherlands in 1923. The disease has been confirmed in France, Belgium, Canada, India, Thailand, England, Hungary, Austria, Denmark and Vietnam, and suspected in China.

DVH is a highly fatal infection of young ducklings. Lesions are primarily in the liver.

It is an acute disease of pheasants, chukars, partridges, turkeys, ducks, pigeons and wild birds. The viruses of EEE and WEE are of public health importance as they infect humans and occasionally cause fatal disease. The disease is further significant because of its link to disease in horses.

Etiology

The arboviruses are grouped into 12 different families. The five arboviruses causing disease in birds are Eastern equine encephalitis (EEE) virus, Western equine encephalitis (WEE) virus, Highland J (HJ) virus, Israel turkey meningoencephalitis (IT) virus and West Nile Virus WNV. The first three are in Togaviridae, and IT and West Nile Virus (WNV) are in Flaviviridae.

WNV was first identified in the West Nile district of Uganda in 1937. Reported in Western Hemisphere for the first time in 1999, in New York City. The virus had until that time been found only in Africa, Eastern Europe, West Asia and the Middle East.

Introduction

This is a disease mainly of the respiratory system affecting domestic poultry, wild birds and zoo birds. Systemic aspergillosis affecting visceral organs and other tissues of the bird’s body is also reported. Reports are also available on eye and brain infections.

Introduction

1. Serious outbreaks of thrush have been observed in chickens, pigeons, geese, turkeys, pheasants, quail, peacock and many other species of birds.
2. Candida albicans is the most commonly isolated fungus from the outbreak. Mucor spp. and Aspergilli were also found in some cases.
3. The outbreaks are associated with unhygienic conditions and nutritional deficiencies. Infection is more common in young birds up to 10 weeks of age. Morbidity is very high and mortality ranges from 10-75%. Clinical signs are not specific. Poor growth and ruffled feathers are only clinical signs.

Etiology

Cryptococcosis (KRIP-toe-cock-co-sis) is caused by the fungus, Cryptococcus neoformans (KRIP-toe-cock-kus knee-O-for-mans). It is found worldwide and primarily affects cats and people with weak immune systems.

It is a fungal infection of skin and the term favus is used for the disease in poultry. The disease is world wide in distribution.

Etiology

Microsporum gallinae, a fungus. The fungus is zoonotic. Lesions of ring worm are produced in humans in contact with infected birds.

Diseases caused by toxic metabolites of fungi are called mycotoxicosis. It affects man and animals including birds. Fungi which grow on feeds and grains in an unfavorable environment mostly cause mycotoxicosis in birds.

The disease is worldwide in distribution and remains the major parasitic problem in the poultry industry. The problems occur principally in poultry maintained on deep litter.

Etiology

Coccidiosis of all classes of poultry is caused by one or more of the many species of coccidia of Eimeria species. In chickens nine main species are encountered. Eimeria tenella, E. necatrix, E. maxima, E. acervulina, E. mitis, E. mivati, E. hagani, E. brunetti and E. preacox.

Cryptosporidiosis is a protozoan disease.

Species

1. C. meleagridis: Infects small intestine.
2. C. baileyi: Infects digestive tract (bursa of Fabricius and cloaca), kidneys and respiratory tract.

Histomoniasis is a protozoan disease.

Etiology

Histomonas meleagridis.

Hosts

Mainly disease of turkey but has also been reported in chickens, peafowl, grouse, quail and gallinaceous birds.

Etiological Agent

Trichomonas gallinae, a flagellate protozoan. Strains vary in pathogenicity. The disease continues to be of significance in pigeons and doves. It has also been reported in raptors.

Introduction

Chickens are considered one of the most important hosts in the epidemiology of Toxoplasma gondii infection because they are an efficient source of infection for cats that excrete the environmentally resistant oocysts and because humans may become infected with this parasite after eating undercooked infected chicken meat.

Poultry meat is an important part of cuisine, consumed widely all over the world; therefore, consumption of uncooked or not properly cooked poultry meat may pose a risk factor for T. gondii infection in humans or animals.

Introduction

A. Common species of nematodes encountered in poultry are:

1. Syngamous trachea (in the respiratory tract) large 2.00cm size live in the trachea and larger bronchi. Many species of domestic and wild birds are affected. Dyspnea, gasping and head shaking are main clinical signs. Treatment is difficult.
2. Ascaridia galli (in the intestine) They parasitize chicken, turkey, pigeon, quail and guineas. In younger birds parasites cause enteritis. In heavily infected birds clinical signs are emaciation and diarrhea.

Introduction

1. Various genera of tapeworms are found in poultry. They are:
   1. Raillietina spp.
   2. Choanotaenia spp.
   3. Davainea spp.
   4. Amebotaenia spp. and
   5. Hymenolepis spp.
2. Tapeworms mainly parasitise the small intestine. Tape worms deprive the bird of its nutrition and cause weight loss and decreased egg production.
3. Out of 3 species of Raillitina, Raillietina echinobothrida is one of the pathogenic species as it produces granuloma at its attachment site (nodular disease).
4. They all require intermediate host for their development.
5. Intermediate hosts are common houseflies, ants, beetles and grasshoppers, which makes control of tapeworms difficult.

HAEMOPROTEUS

Host

Infection with Haemoproteus species is host specific.

H. meleagridis – domestic poultry and pet birds

H. olumbae in pigeons

H. nettionis in waterfowl.

LICE

Introduction

Lice are common ectoparasites of birds. There are many species of bird lice and are found on chicken, turkey, guinea fowl, duck, goose and pigeon. Lice species prefer a different part of the body. Most of them are straw colour and measure 1-10 mm. Lice from one host can parasitise another host if they are in close contact. For example, a louse from chicken can parasitise guinea fowls kept on the same premises. Hence, the species of lice is determined if cross contamination from another species is suspected. Lice are not highly pathogenic to mature birds. However, severe lousiness may lead to weight loss, as well as low production and death.

Vitamin A

Source of Vitamin

Berseem, legumes, alfalfa or other grass meal, fish oils, yellow corn, palm oil, commercial Vitamin A concentrate

CALCIUM & PHOSPHORUS

Source of mineral

Soluble grits (Limestone grits containing chiefly CaCo3) which is soluble in acid medium of crop. It differs from insoluble grits (gravel, granites, sand etc.) which acts only mechanically in the gizzard.

Pododermatitis or bumble foot has many causes including excess weight bearing from obesity or unequal weight bearing between the two feet as a result of lameness of one foot, causing less weight to be placed on that foot and more on the contralateral foot, or from abnormal abrasions of the plantar surface from inappropriate substrate (too sharp or rough, wire, etc.), decreased blood supply to the foot (sometimes from lack of exercise), trauma, or standing for prolonged periods of time, especially in ducks that are not provided with adequate swimming opportunities.

Bumble foot is commonly seen in waterfowl under one or more of the following conditions; obesity, hard substrate, lack of access to water to swim in, malnutrition and underlying disease.

This is localized infection of the feet. It is seen as bulbous swelling of the footpad and surrounding tissues. It appears usually after an injury to the foot pad and causes lameness in one or both feet. Pododermatitis is divided into varying grades depending on the literature source used, but generally includes mild, moderate, and severe grades with the severe grades including osteomyelitis. Infection by various bacteria commonly occurs and superficial wounds may not be present. Sometimes ulcers are formed on the planter surface of the foot. The layers become lame and production lowers, sometimes completely stops. On opening the swelling a foul smelling thick pus is found. The condition is more common in heavy breeds. Early surgery and antibiotic therapy may control the condition. Removal of high roosts reduces the incidence.

Cage layer fatigue is a term used to describe leg weakness and acute deaths in chickens in cages, and is caused by inadequate calcium, phosphorus and Vitamin D levels in the blood stream. Calcium is required for muscle function, bone formation, and egg shell formation. This condition may be seen even in floor birds under certain conditions. It is seen most often in young hens early in production.

Introduction

Although the causative agent for the condition has not been identified, experimental studies indicate the association of parvovirus and or Astrovirus. Under experimental conditions, the virus induces clinical signs onlyin fast growing broiler chickens. The clinical signs, based on experimental inoculation of chickens, consist of watery or mucoid mustard yellow colour diarrhoea within 3-5 days after infection. Chickens become stunted, and a variable number of such chickens die during 10 and 20 days. Pronounced weight loss is in around four week’s age. The mortality is low (5 - 10%) however, the morbidity is very high (50 - 80%).

Introduction

1. The condition has been reported the world wide in growing broiler chickens.
2. The affected birds show clinical signs usually during 4 - 5 weeks of age. The clinically affected birds are smaller, listless with ruffled feathers, pale head and shrunken comb. Severely affected birds have distended abdomen, which restricts their normal movement. Death may occur suddenly, and not all the broilers which die of the condition have ascites. The incidence of the disease varies between 2 to 20%.

Introduction

Hypoglycemia Spiking mortality syndrome is a disease in broilers, characterized by low mortality with sudden onset of high mortality. The affected birds are clinically hypoglycemic.

There is no known aetiology.

The condition is characterized by proventriculitis and dilatation of proventriculus.

Etiology

The cause of transmissible viral proventriculitis (TVP) is a birnavirus referred as Chicken proventricular necrosis virus (CPNV). TVP is a disease of 3-8 week-old broiler.

Seen in mature chickens. Condition results from myocardial degeneration which causes bilateral ventricular hypertrophy and dilation. Etiology is not known.

Round heart disease in turkey causes mortality in 1-4 weeks of age. Lesions are severe cardiomyopathy, ascites, hydropericardium and generalized congestion of tissues. No aetiology is known.

The chemical composition and digestibility of feedstuffs influence their nutritive value for animal production. Therefore, assessment of nutritive value of feedstuffs continues to be one of the top priority areas in animal production research. Although traditionally the feedstuffs were evaluated by performance studies and digestion trials, such techniques are expensive and requires more time and labour. Continued search for alternatives to animal feeding experiments have led to the development of feed evaluation systems that are rapid and economical.

In general, there are two kinds of laboratory analyses — Chemical analyses and Biological tests with rumen micro-organisms or purified enzymes. Biological tests give direct estimates of digestibility, but are lengthier and more expensive. Chemical analyses are cheaper and rapid, but do not give direct estimates of nutritive value. The statistical association between the chemical components and quality need to be established to predict the nutritive value.

The estimation of digestibility by feeding trials with sheep or other ruminants is laborious and requires large quantities of feed. Therefore, the chemical composition of feedstuffs are used to predict digestibility by making use of established mathematical relationship between digestibility and composition. However, since the relationship between digestibility and chemical composition varies with the type of feedstuffs, for each group of feedstuffs, mathematical equations will have to be developed by relating chemical composition with in vivo digestibility. In spite of this, the errors associated with this approach of predicting digestibility is large. This has led to the development of techniques that would mimic digestive function of the ruminant in the laboratory.

In vitro methods of feed evaluation using rumen fluid and/or digestive enzymes are the most widely used techniques in ruminant feed evaluation.Although,the technique adopted in different laboratories differ, the principle of the technique is essentially a partially simulated rumen environment in vitro by incubating rumen fluid anaerobically in buffered medium at 39°C for variable period of time. Currently the most commonly used rumen in vitro techniques are,

Although in vitro rumen studies of digestibility determination simulates rumen fermentation to some extent, it is almost impossible to incorporate all dynamics of rumen environment in these techniques. Therefore, the in situ Dacron bag technique was developed as an alternative to the in vitro rumen studies (Ørskov and McDonald, 1979). This technique involves placement of feedstuffs in bags made of indigestible fabrics such as nylon, Dacron or silk, directly in the rumen. The loss of dry matter or of any feed component after specific incubation period are measured gravimetrically to determine the rate and extent of degradation.

This technique is widely used, but the procedure differ among the laboratories.Improved methods utilise bags of specific pore size and control the ratio of sample weight to surface area of the bag.Bags with a large ratio of surface area to sample size minimise the error.Optimum pore size is about 40 microns. Smaller pore size retards the entry of organisms and thus inhibit optimum fermentation while larger ones permit transit of lignified particles.

Although the Dacron bag technique for protein degradation measurement is relatively simple and not too expensive as compared to in vivo measurements, the technique is not easily adaptable in laboratories that are not fully equipped to maintain cannulated animals. Therefore, different alternative approaches such as measurement of protein solubilities in buffer, enzymes and detergent solutions have been tried (Pichard and Van Soest, 1978; Krishnamoorthy et al., 1982, 1983, 1995; Aufrere et al.,1991; Prabhu et al., 1996; Licitra et al., 1996 and 1998). The advantages of these approaches are that, they are simple, rapid, economical and repeatable. However, since the enzymes used are not of rumen microbial origin, degradation obtained from these enzymes may not be a true .reflection of degradation occurring in the rumen. Nevertheless, because of their simplicity and rapidity, in situations where large number of samples are to be compared, in vitro techniques serve as useful tools.

Different enzymatic methods have been proposed as potential alternatives to rumen inoculum studies to determine dry matter digestibility and protein degradation. However, the type of enzyme used and the procedure adopted differ (Marten and Barnes, 1979). The enzyme methods offer distinct advantage under circumstances of the difficulties in maintaining rumen fistulated animals as a source of rumen inoculum. Since, the enzymes used in these techniques are commercially available enzyme preparations, and are not of rumen microbial origin, the digestibility obtained from these techniques are related to in vivo digestibility by means of mathematical equations. Therefore, equations developed to predict energy content using enzyme techniques differ with the type of feedstuff and type of enzymes used in the technique (Table 5.1.) (Martens and Barnes, 1979). The enzyme methods are popular among the feed compounding industries to evaluate raw materials and compound feeds.

The method used by DeBoever et al. (1986) to determine digestibility of mixed feeds is given below.

6.1 Kinetics of Rumen Digestion

The rate and extent of digestion of dry matter or organic matter in the rumen is regarded as the important parameter to predict voluntary feed intake (Khazaal et al., 1993; Blummel,1994). Voluntary feed intake is responsible for more than 50 per cent of the variations in animal response to the diet (Van Soest, 1994) and with low quality unsupplemented roughages, this can be as much as 93% (Blumme1,1994). Therefore, any parameter of feed evaluation that would indicate the voluntary feed intake would be a useful parameter to judge the quality of feedstuff. The rate of digestion of any feed component can be measured by determining extent of digestion at intervals of time. Therefore, the techniques for determining extent of digestion, such as the rumen in vitro techniques (Tilley and Terry, 1963; Goering and Van Soest, 1970) or the in situ Dacron bag technique have been adopted to derive rate of degradation of dry matter of any particular component of the feedstuff. However, unlike in determining the extent of digestion, wherein the incubation is turned off at one particular time (normally 48 hours), measurement of rate of digestion, requires termination of incubation at several points between the start of incubation and until at least 90% of the potentially digestible dry matter is digested (72 or 96 hours). This generates a large number of samples for analysis.

In gas production technique, since gas produced from digestion of substrate is accumulated in the incubations, measurement of gas at different times of incubation would reflect the extent of digestion at different times of incubation. Therefore, unlike with other in vitro / in situ techniques wherein, digestion is determined from the gravimetric disappearance of feed at different times of incubation, gas production technique offers the possibility of using cumulative gas production at different times of incubation to measure the rate of digestion. Thus, a single incubation of feedstuffs is adequate to measure the rate of gas production.

Introduction

In ruminants,nutritional studies are very complicated unlike non ruminants where it is quite simple. In non-ruminants, analysis of feed taken and faeces voided by the animal gives overall picture of digestion and nutrient availability to the animal. In ruminants, since it has a complex microbial digestive system (rumen) within the animal digestive system, the analysis of the feed taken and faeces voided will not express the whole processes in the GI tract of the animal. To have complete picture, it is necessary to study at the site of microbial digestion (rumen). For such study, samples from the rumen have to be drawn and analyzed for metabolities, microbial enzymes etc.

Principle

Nucleic acids leaving the rumen are mainly of microbial origin which are extensively digested in the small intestine and the purines liberated are absorbed. Only a small amount of absorbed purines are utilized by the host animal, the rest are metabolised forming hypoxanthine, xanthine, uric acid and allantoin. These metabolites are excreted mainly through urine. Therefore, with the understanding of how urinary excretion of purine derivatives (PD) respond to purine absorption i.e. the response curve of PD excretion to purine input into intestines, the microbial purine outflow from the rumen and the microbial N supply to the ruminant animal can be estimated by measuring the purine derivatives excretion through urine.

Principle

Polyethylene glycol (PEG) is a high molecular weight compound which is inert to rumen fermentation. The concentration in the rumen liquor declines with the passage of digesta from rumen to lower G.I. tract and is proportional to time. Protein free filtrate of rumen liquor gives turbidity in the presence of trichloro acetic acid and barium chloride which is a measure of PEG concentration at different post feeding hours.

Nutrition plays a pivotal role for the animal research, be it health or production. Research in animal nutrition employs many basic techniques and chromatography is one of them. Chromatographic processes can be defined as separation techniques involving mass transfer between stationary and mobile phases. Various types of chromatography have one application or the other in analysis of food/feed components (Day and Williamson, 2001), quantitation of nutrients as well as the characterization of the effect of nutrients in biological samples like serum/plasma or tissues (Merken and Beecher, 2000).

A. Principle

Basically all chromatographic systems consist of the stationary phase that may be solid,gel,liquid or a solid/liquid mixture that is immobilized and the mobile phase, which may be gas or liquid and it flows over or through the stationary phase. This partition is achieved in one of the following ways:

Adsorption chromatography : It is one of the oldest types of chromatography. It utilizes a mobile liquid or a gaseous phase that is adsorbed onto the surface of a stationary solid phase. The equilibrium between the mobile and the stationary phase accounts the separation of different solutes e.g. adsorption chromatography, hydrophobic interaction chromatography.

Partition chromatography : It is based on a thin film formed on the surface of a solid support by a liquid stationary phase. Solutes equilibrate between the mobile and the stationary liquid (e.g. partition chromatography, reverse phase chromatography, gas-liquid chromatography, etc.).

Chromatography is one of the most effective technique for accurate, fast and convenient separation and identification of the components of a mixture. The method was developed by Russian botanist Mikhail Tswett (1906), described by Karl Runge (1855). Martin and Synage (1944) received Noble Prize for developing methodology of partition Chromatography.

Partition chromatography

Partition chromatogaphy is a system comprising of two physically distinguished components - a mobile component or phase and a stationary component or phase. A mixture of substances which are to be separated is placed on the system and separation takes place on the basis of difference in distribution of molecular species in two phases. Relative movement is a result of driving force and retarding effects.

Stationary phase is the sorbent, which may be liquid or paper or gel. If it is liquid then it is held stationary by adsorbing on a solid support or matrix. The mobile phase may be solvent or developer or a gas. Since the two phases are immiscible, the partitioning is defined as the distribution of solute in two immisicible phases which are in contact with one another. When a column is filled with the sorbent and solvent the two phases form a large number of theoretical plates. Each plate contains both the phases. Solutes in solution (mixture of substances to be separated) is layered on the top of the column and when it enters to the column it distributes in the two phases. The ratio of the concentration of a solute in two phases is called its partition coefficient. The resolution of solutes improves as the length of stationary phase increases.

Various products of karanj (Pongamia glabra) are utilized for industrial, health and animal agricultural application in the Indian subcontinent. Despite a rich source of protein (CP 28 —34 %), karanj (honge) cake is found to be slightly bitter in taste and toxic owing to the presence of furanoflavonoid (Karanjin), restricting its safe inclusion in the livestock diets. Though a non polar solvent, soxhlet extraction of karanj seed cake with petroleum ether/ acetone drastically reduces karanjin content. The residual cake left after solvent extraction is proved to be safe as animal feed supplement.

Estimation of karanjin

The samples can be analysed for the toxin, karanjin as per the method of Prabhu et al. (2002).

Extraction of Karanjin from Raw and Processed Cake

Exactly 25 gm of ground and thoroughly mixed sample is weighed and transferred into the thimble and extracted for 12h using 200ml of freshly distilled methanol as solvent. Methanol extract is then cooled and filtered into preweighted round bottom flask using Whatman No.1 filter paper.The excess methanol is distilled off under vacuum. The flask containing the extract is weighed again to obtain the weight of extract by subtracting the empty flask’s weight. Sufficient amount of moisture free extract is transferred into vials for further analysis.

Neem seed cake (NSC) despite of being rich in protein is not used as animal feed due to the presence of large number of toxic/bitter compounds in it. Studies have shown that NSC can be safely included the ration of animals after water washing / alkali/ urea treatment. These treatment methods appear to remove / reduce or largely inactivate the toxic principles present in NSC. In order to assess the quality/safety of the treated product, quantification of the residual toxic compounds is essential. One such compound is azadirachtin. It has been reported to be biologically most active.

One of the best techniques for the estimation of azadirachtin is by using high performance liquid chromatography (HPLC).