Indigenous germplasm: Role in improving poultry production
D. P. SINGH
Native breeds as reservoir of major genes:
Great variability is observed in morphological characteristics of the native birds. With respect to body weight three variants have been distinguished i.e. dwarf, normal and heavy body weights. Plumage pigmentation tends mainly towards blackish and brownish colours showing extended and pied colourations. Plumage distribution is mainly normal with special forms such as crest, naked neck, frizzle type appear sporadically. The comb is single but rose, pea and walnut are also found. The shank and skin are also frequently pigmented showing green and blue variants. In addition to this melanin deposition in skin, meat, internal organs and bones in some breeds (e.g. Kadakanath) are also encountered. Some of these variants are due to the presence of major morphological marker genes, which increases the adaptability of these breeds to tropical climatic environments. In last two decades a series of experiments were conducted at Institute of Animal Production, Technical University of Berlin, Germany, utilizing the native breeds of many countries and several major genes were identified. The study of effects of these genes on economic traits indicated that some of these are related to tropical adaptability. Direct and indirect effects of such genes have been presented in table-1.
Scope for utilization of native germplasm for improvement in tropical adaptability of high yielding exotic birds
Poultry production in India came out from back yard venture to full-fledged poultry industry in last three decades. High yielding germplasm have contributed significantly in the progress of this enterprise. Most of the high yielding exotic breeds have temperate origin or have been developed in temperate climatic conditions. India being a tropical country having vast hot and humid area around coastal regions is not suitable for full expression of its production potential. In the peak summer and humid months, high yielding stocks suffer from decreased feed consumption, low egg production and reduction in the feed efficiency. The egg quality is also being affected in these months. Improvement in management practices such as provision of environmentally controlled houses or houses with cooling devices might not be a desirable proposition for poor farmers as country is facing acute shortage of electricity. It will therefore be desirable to breed birds suitable to the tropical environment. Heat tolerance can be improved through:
(1) More efficient thermoregulation
(ii) Through enlarged naked body surface
(iii) Lowering basal metabolism
(iv) Reduced feathering intensity
(v) Creating specific colours by obtaining skin having melanin and non-pigmented feathers
Utilization of identified tropical oriented major genes are capable to introduce the said activities and thus are capable to increase tropical adaptability. All these major genes are virtually absent in the high yielding exotic breeds but available in our indigenous breeds of chicken. Systematic studies for identification of various genomes and major genes in our indigenous breeds are lacking. Attempts have been made to study some of the breeds at Central Avian Research Institute, Izatnagar. Slow feathering (K), Non-inhibitor dermal melanin (id), Fibromelanosis (Fm), Naked neck (Na) and Frizzling (F) are some of the important tropical oriented major genes identified in Indian native chicken. Preliminary study on general immunocompetence status suggested that high producing exotic stocks are least efficient with respect to immune system in comparison to native breeds. Thus the general saying that indigenous breeds are more resistant to general disease than the high yielding exotic breeds seems to be true.
Exploitation of native germplasm for improvement in tropical adaptability of high yielding exotic germplasm at CARI, Izatnagar
Work on utilization of Naked neck and Frizzling genes identified in the Indian native chicken for the improvement of tropical adaptability of exotic broiler and layer birds are going on since more than a decade. Two broiler lines CARI Mrityunjay (with Naked neck gene) and CARI Tropicana (with Naked neck and Frizzle genes) have been released. Growth and production potentialities of these lines are comparable to international broiler with better tropical adaptability. Development of high yielding Naked neck and Frizzling layer lines are under progress and expected to be released during couple of years.
Scope for utilization of native germplasm for improvement in family poultry production
Traditional backyard poultry keeping is in practice since time immemorial. During the past three decades the popularity of scavenging chicken has reduced drastically due to the low productivity of the native chicken used in this system. . Most of the crossbreds viz. Vanraja, Giriraja, Kroiler and CARI Devendra for meat and Krishna-J, Krishipriya, Grampriya and CARI-Gold for egg (summarized by Khan, 2000) developed for rural poultry production in India are either cross of two exotic breeds or line cross High mortality rate, malnutrition and adverse environmental conditions of villages are antagonistic to the successful raising of heavy weight or high producing types of poultry. Farmers are aware that these foreign ‘laying machine’ are not able to look after themselves very efficiently but will produce many eggs if they are fed and cared properly. Their negative correlation with low broodiness will ensure their rejection when they try to multiply and establish themselves. Even before this happens, the association of high egg numbers with a lack of alertness to predators, poor colour camouflage and short legs which compromises the ability to run fast will, in all likelihood, cause their presence in the gene pool to be reduced quickly (Tadelle et. al, 2000).
In spite of the lack of most of the characteristics essential of scavenging chicken, the above mentioned genotypes got popularity as suitable rural poultry germplasm as due input in the form of supplementary feeding, health coverage and proper care were provided to these genotypes i.e. they are fed and cared properly. The rearing of even the elite flock of layer and broiler might be possible in rural areas with the application of advanced management practices as is practiced in intensive system. But improved management practices might not be possible for a large group of the downtrodden societies who are the sole owner of the traditional scavenging chicken. In real sense rural poultry is based on low inputs and outputs and is part of a system known as ‘balanced farming’. The village poultry populations can be pictured as a gene pool of genes under pressure from many directions, principally disease, predation, lack of food and drinking water of high quality, and poor housing. It is essential to evaluate and understand the local production system, their limitations and opportunity, the circumstances under which such traditional system came to existence and how they can be gradually improved. Introduction of crossbred with coloured feather is probably not the complete answer (Khan, 2002). The characteristics essential suggested by various workers ( Rao, 2002 and Singh, 2003) for scavenging chicken are as follows:
Colour of the bird : Majority of the people in rural areas have a strong liking for colored birds, not from the aesthetic point of view but from the survival point of view, since colored bird escape from the predators being camouflaged by their color as against white or light colored bird. Better immunocompetence has been reported for colored birds in comparison to white plumage.
Morphplogy and temperament of the bird : In backyard areas where there is always danger of predators like wild cats, too many stray dogs etc. a lighter bird with long shank and strong wings has a greater chance of escaping from predators by fast running and flying till they reach a safer place. If possible the birds should have an aggressive behavior, which may act as deterrent to some extent.
Productivity of the birds: Under the multi stress environment of rural area heavy dual-purpose bird cannot perform well as lighter layer bird both from the point of survival and economic parameters. Low nutrient availability and long distance to be covered to gather the nutrients suggest the choice of light layer bird. Further it has been observed that females of dual-purpose birds are sold away lured by good price early in life interrupting its life cycle (Rao, 2002). Light/ medium bird has also been recommended for the semi succulent areas with limited/seasonal availability of greens and insect population (Khan, 2001).
Disease resistance: The birds to be used in the scavenging must have the better immunocompetence as there is lack of availability of good quality food and drinking water and they have to roam into dirty surroundings in search of food. In addition, appropriate prophylactic measures are not possible in remote areas.
Tropical adaptability: Tropicaloriented major genes might be desirable for better productivity in tropical environment of the country. It would be a desirable proposition to incorporate such gene in new developed birds for scavenging.
Self Propagation: Self propagatingcapacity is essential requirement for the scavenging bird as it might not be possible always to get the replacement chicks from the hatchery for the remote areas and also due financial constraints for weaker sections. The characteristics of broodiness will be essential to achieve this objective.
Improved native breeds or a cross of native breed with exotic would be a good proposition for the ideal replacement of native scavenging chicken. Thus native germplasm may play vital role in improvement of rural poultry production.
Development of scavenging chicken at CARI, Izatnagar with native fowl base
Four types of high yielding germplasm suitable for backyard production have been developed with four different native fowl base especially suitable for different climatic regions of the country at Central Avian Research Institute, Izatnagar. These birds have combination of 50% native and 50% exotic blood and possess other characteristic essentials for backyard / scavenging poultry production. Phenotypically these birds look like their original native breed with two or three times increased egg production with bigger egg weight, better tropical adaptability and disease resistance along with capability of bearing the stress of poor feeding and management (Table-2).
CARI NlRBHEEK: It is cross of Indian native breed Aseel with Cari Red. Birds are active, larger in built, pugnacious in nature with high stamina and majestic gait. They are able to save themselves from their predators due to its fighting characters and activeness and are adapted to all climatic zones of the country.
CARI SHYAMA: It is cross of Kadakanath breed of Indian native chicken with Cari Red. Birds have plumage of various colours dominated by black. The skin, beak, shank, toes and soles are dark gray colour. The peculiarity of this bird is that most of the internal organs show the characteristics black pigmentation. Varying degree of blackish colouration is also found in skeletal muscles, tendons, nerves, meninges, brain and bone marrow. The black colour of muscles and tissues is due to deposition of melanin pigment, which causes increase in protein, and decrease of fat and muscle fiber.
UPCARI: Indian native chicken with Frizzle plumage has been crossed with Cari Red for development of UPCARI birds These multicoloured birds have single comb and medium body size. Presence of Frizzle plumage helps in fast heat dissipation due to which birds are better adapted to tropical climate especially for arid zones.
HITCARI: Indian native chicken with Naked neck plumage has been crossed with Cari Red for development of HITCARI birds which are adapted to tropical climate specially for hot and humid coastal region of the country. These multicoloured birds have single as well as pea comb and birds are larger in built
The economic importance of single- purpose highly productive breeds and lines are distorting the perception of the value of multipurpose breeds that are adapted to the local conditions. The replacement of these local breeds may lead to their extinction and hence to an unrecorded loss of genetic variation. The native genetic resources are the gold mines of genomes and major genes for improvement of high yielding exotic germplasm for tropical adaptability and disease resistance. Genetically diverse breeds provide an indispensable sourse for search to improve our understanding of the genomic mechanism that underlie biodiversity, physiological functions, disease resistance and performance traits. Highly differentiated strains are the basis to develop resourse populations used in quantitative trait loci mapping, detection and utilization for marker-assisted selection. In addition, the native germplasm have great utility for backyard poultry production. Conservation of native genetic resources is of prime importance but a very costly affair. Nowadays, the general public does not understand well the reason or the need to preserve old breeds; nor it fully understands the working relationship between farmers and their animal partners (Dohner, 2001). Exploitation of the indigenous genetic resources might play vital role in conservation of desirable genes and genomes through its utilization.
Table 1. Tropical relevant genes in local fowl (HORST, 1988)
Table-2. Performance of economic traits under farm and farmers door
|Source : IPSACON-2005|