This paperprovides a short history of poultry production development in Lithuania and the results of breeding work achieved overa thirty-year period.

The year 1965 can be considered as the beginning of breeding work, when the development of specialised strains of laying hens began. On the basis of these strains, after testing them for combining ability, the first two-way cross of laying hens “Neringa” was developed in 1975. The egg production of the commercial layers of this cross on poultry farms in Lithuania was 239 eggs in 10 laying months. After nearly ten years' purposeful work with initial lines, “Hisex White” from the Euribrid company, a more productive three-way hybrid combination was developed (1984), which was denominated as the cross “Kelmò–1”. As a result of further breeding work, the laying rate of commercial hens increased to 276 eggs peryear.

In 1968, breeding work with the initial lines of meat poultry was started. Using lines developed by “Shaver”, “Euribrid”, and “Arbor Acres” companies, Lithuanian breeders developed 5 lines of Plymouth Rock and 3 lines of Cornish breeds.

On the basis of the results from the analysis of the combining ability, a four-way broiler cross “Baltika–4” was developed in 1971 with a daily weight gain of 26.8 grams, and a four-way cross “Baltika–10” with a daily weight gain of 37.5 grams was developed in 1983. During the period of 1989–1990, the experimental four-way cross with a daily weight gain of 41.8 grams was developed.

The activities of Lithuanian researchers in the fields of poultry breeding, nutrition and housing technologies together with the results of breeding and those of commercial farms, exerted a positive effect on the development of Lithuanian poultry production1.

One of the keys to success was the development of a closed vertically intergrated farming system, i.e. primary breeding farm, grandparent reproduction farm, parent stock reproduction farm, the multiplication results of which are used by production farms and large poultry farms.

As a results of complex work, Lithuanian state poultry production farms produced 13.5 kg of poultry meat and 273 eggs per capita in 1990.

To understand the relationship between the gastrointestinal inhabiting microbial community and broiler health, a literature review is presented. The available information on the development of gut microbial community, the relationship between commensal microflora and digestive function, the role of gut microorganisms on competitive exclusion of chickens against pathogens, and modulation of the gut microbial community by addition of prebiotics to the diet is summarized. Gut dominant microbial communities become more complex as broilers grow older. The establishment of the dominant bacterial community is affected by dietary and host-related factors. Dietary prebiotics can modulate bacterial community shift towards non-harmful bacteria, which is beneficial for the health of broiler chickens. Gut commensal microorganisms play an important role in the prevention of colonization by pathogens in the gastrointestinal tract of chickens, a process known as competitive exclusion. In conclusion, the dilemma caused by the forthcoming ban of antibiotics feed additives and need to maintain the intestinal health of broiler chickens, has produced an enormous interest in finding alternatives. Modulating the intestinal microbial community in a healthy direction, by dietary ingredients such as prebiotics, could be a good solution.

Around the world, there are 20 types of wild and about 70 domestic quail breeds or strains, including laboratory and commercial quail. Although all domestic quails were derived from wild strains, many obvious differences are evident today. However, how these differences occurred and which wild population was the first to be domesticated, remains unclear. This paper systematically presents the history of the development of domestic quail in China from 770 B.C. to the end of the 20 century. Taking into account recent research on some structural loci of domestic and wild quail, and in the light of recent survey reports of the present general situation of these birds, particularly in respect of their ecological performance and differences between wild and domestic quail, this review puts forward a new thesis forresolving the current uncertainty about the origin of domestic quail. It is suggested that unlike those of Japanese origin, Chinese quail are probably the earlier and more direct ancestorof most kinds of the domestic quail found around the world. Moreover, the review analyzes the possible evolutionary path to domestic quail, which is mainly a result of the flow of people from Japan to China. On the assumption that more and more wild quail populations are endangered, it aims to provide a basis forrenewing knowledge of wild quail resources and supporting the protection and use of these valuable worldwide stocks. This is especially important in China, the last country in the world to have so many wild quail populations. Furthermore, this new insight can promote and assist the world commercial quail industry to develop and flourish.

A previous study by this group demonstrated that a high carbon dioxide tension in venous blood (pvCO2) of juvenile broiler chickens is a reliable predictor for ascites susceptibility.

In a new experiment with five highly selected genetic stocks and two ascites resistant old breeds we studied levels and variability of pvCO2 within each stock at an early age. Effects of different selection traits (principally growth rate) between fast growing sire lines and slower growing dam lines and a commercial hybrid on blood gas (pCO2, pO2) tensions, pH and haematocrit in venous and arterial blood were examined at different ages and compared to values found in ascites resistant breeds. All birds were housed in floor pens in a climate controlled room and subjected to an ascites-predisposing cold environment.

From each stock, 16 birds with the highest (high risk: HRc) and 16 birds with the lowest (low risk: LRc) pvCO2 values were selected at 12 days of age. These birds were marked for future blood sampling to determine changes in haematological characteristics with age and to relate these values to ascites susceptibility. At day 14, eight non-selected birds from each stock were randomly chosen for dissection to determine initial pulmonary arterial pressure index (API) values. Subsequently, all birds were allotted to 8 floor pens (13 birds per pen including two HRc and two LRc birds) per stock. Production performances from 104 birds per stock were measured from 16 to 33 days of age (feed intake (FI); feed conversion ratio (FCR); body weight (BW) at day 33). Mortality was recorded during the complete experimental period. At 5 wk of age, all HRc and LRc birds were necropsied and API values were recorded, which was used to classify the severity of the ascites syndrome.

A convincing effect of pvCO2 values in juvenile chickens on API at 5 wk of age in modern lines confirmed results obtained in the previous study. At an early age, pvO2 values were much less predictive for high pulmonary pressure induced ascites at wk 5 than pvCO2 values. Hypercapnia combined with low blood pH values and followed by hypoxemia (inducing high haematocrit values) provoked a marked high incidence of ascites and high API values in modern breeds.

A total absence of ascitic symptoms within native breeds corresponded with unchanged low API values during ageing from 12 to 33 days of age and with lower pCO2 values in venous and arterial blood compared to modern breeds at all ages. The pvCO2 difference (mean values) between HRc and LRc groups were similar for all modern lines irrespective of age and showed no relationship to growth rate. API, as a reliable indicator for ascites susceptibility, of modern breed chickens correlated with pvCO2 values, but not with growth rate. The high correlation between pvCO2 in juvenile chickens and API values at 5 wk of age indicated that a strong genetic selection pressure on low pvCO2 values at an early age will be an effective method to reduce decisively the occurrence of the ascites syndrome at sea level.

A systematic review of investigations on productivity, mortality and cannibalism of laying hens housed in aviaries is presented. In Part One we reviewed the studies that compared these parameters between laying hens housed in aviaries and in conventional cages. In Part Two we investigated the relative impact of strain, beak trimming and rearing condition on productivity and mortality in aviaries. The comparative analysis revealed that aviary hens consumed 3.0 % more food than caged hens, and food conversion was 6.7 % higher in aviaries than in cages. On the other hand, the mortality rate and cannibalism rate did not differ significantly between the two housing systems. The analysis of causes of variation in productivity, mortality rate and cannibalism rate in aviaries revealed a strong effect of strain. Beak trimming was associated with a reduced prevalence of cannibalism rates but had no effect on overall mortality. It also reduced egg weight and food consumption. Early access to litter during the rearing period had a positive effect on egg weight; egg mass, food conversion and mortality rate. In conclusion, we found a slightly reduced productivity of aviaries in relation to cages although the mortality rates and the prevalence of cannibalism did not differ between these housing systems. To further improve productivity and reduce mortality of hens housed in aviaries we recommend the choice of suitable strains and the implementation of improved rearing conditions including early access to litter.