Factors affecting eggs hatchability

Incubation temperature is not only important for normal embryonic development and hatching success but also affect post hatch performance. It is recommended that incubation temperature is adapted to the natural heat production pattern of the incubating egg to obtain the highest hatchability with good-quality chicks. A recent publication of Lourens et al.

Factors affecting eggs hatchability

If waters are polluted with metals at greater concentrations, the source may be traced back to ore mining and processing, to smelting plants, rolling mills plants for the surface treatment of metals, film, textile and leather industries and other sources.

Atmospheric precipitation can wash out metals in dust and aerosols generated by the burning Factors affecting eggs hatchability fossil fuels, by the exhaust gases of motor vehicles, and from other sources.

The mechanism of the toxic action of metals on fish is varied. Most of the metals have a great affinity for amino acids and the SH groups of proteins: The toxicity of metals to fish is significantly affected by the form in which they occur in water.

The ionic forms Factors affecting eggs hatchability metals or simple inorganic compounds are more toxic than complex inorganic or organic compounds. The toxic action of metals is particularly pronounced in the early stages of development of the fish.

3 Hatching Egg Transfer

Another potentially harmful property of many metals is their ability to accumulate in the sediments and in the aquatic flora and fauna bioaccumulation.

Hence, the concentration of these metals in water does not provide a true indication of the total pollution of the aquatic medium; it is better to use the content of metals in the sediments, and especially also in the bodies of predatory fish which are the final link in the food chain, as an indicator.

The metals found to be of highest importance to fisheries in practice include aluminium, chromium, iron, nickel, copper, zinc, arsenic, cadmium, mercury and lead.

Aluminium is soluble at pH values below 6. At higher pH values, aluminium is precipitated as the hydroxide, which can flocculate in the water.

It is possible that freshly precipated aluminium as a colloid may be toxic; the fully flocculated hydroxide has a low toxicity similar to that of suspended solids in general. In toxicity tests, rainbow trout fry were exposed to different aluminium concentrations at a pH of 7.

A concentration as low as 0. When an even lower concentration, 0. A mass kill of maraena and peled fry, reared in a public supply water clarified by flocculated aluminium sulphate, is a practical example. The aluminium concentration of the water was up to 0. All the fry of maraena and peled died within 10—14 days of hatching.

It is not known whether this was due to ionic aluminium or to micro flocs affecting fish respiration. Of these two forms, chromium III is poorly soluble and is readily adsorbed onto surfaces, so that the much more soluble chromium VI is the most common form in fresh water. For this reason, maximum admissible concentrations for chromium are generally based on toxicity data for the hexavalent form.

Chromium compounds in the trivalent state III are more toxic to fish and other aquatic organisms than are those in the hexavalent state VI. From the LC50 data obtained for different fish species, chromium III compounds are among those substances with a high toxicity to fish LC50s of 2.

The toxicity of chromium compounds to fish is also considerably affected by the physico-chemical properties of water, especially the pH value and the concentrations of calcium and magnesium. At a high pH and a high concentration of calcium, the toxicity of chromium to aquatic organisms is reduced, compared to that in soft acid water.

With acute poisoning by chromium compounds, the body surface of the fish is covered with mucus, the respiratory epithelium of the gills is damaged and the fish die with symptoms of suffocation. Fish suffering from chronic chromium intoxication accumulate an orange yellow liquid in their body cavity.

The ratio of these two forms of iron depends on the oxygen concentration in the water, the pH and on other chemical properties of the water. Fish may be harmed by iron compounds in poorly oxygenated waters with a low pH where the iron is present mainly in the form of soluble compounds.

Because the gill surface of the fish tends to be alkaline, soluble ferrous iron can be oxidized to insoluble ferric compounds which then cover the gill lamellae and inhibit respiration.

At a low water temperature and in the presence of iron, iron-depositing bacteria will multiply rapidly on the gills and further contribute to the oxidation of ferrous iron compounds.

Their filamentous colonies cover the gills; at first they are colourless but later the precipitated iron gives them a brown colour. The precipitated iron compounds and tufts of the iron bacteria reduce the gill area available for respiration, damage the respiratory epithelium and may thus suffocate the fish.

In a similar toxic action, iron compounds can precipitate on the surface of fish eggs which then die due to a lack of oxygen.

Factors affecting eggs hatchability

The lethal concentration of iron for fish is not easy to measure because it depends to a large extent on the physico-chemical properties of the water.

In cyprinid culture, it is generally accepted that the concentration of the soluble ionized forms of iron should not exceed 0.

CONTROL OF MAREK'S DISEASE IN CHICKENS

Nickel compounds are of medium toxicity to fish.Hatchability for small eggs is lower than medium and large eggs. There are many factors contributing to the failure of a fertile egg to hatch which include lethal genes, insufficient nutrients in the egg and exposure to conditions that do not meet the needs of the developing embryo.

Pre‐storage fumigation of almost un‐contaminated eggs had no effect on hatchability even after storage for 8 d. Storing eggs in unsealed polythene bags did not affect hatchability of eggs stored for 5 or 8 d.

3. Eggs stored for 2 d hatched better . INTRODUCTION Several billion birds from over species breed each year in Canada (Blancher ), in a wide variety of habitats.

Polychlorinated biphenyls and polychlorinated terphenyls (PCBs and PCTs) (HSG 68, )

Landbirds, i.e., songbirds, raptors, upland gamebirds, represent most of the birds in Canada and tend to have large and widespread populations. Carlos JP. (). Comments on Fluoride. Journal of Pedodontics Winter: CDC.

(). Recommendations for Using Fluoride to Prevent and Control Dental Caries in the United States. The poultry club, founded , is a registered charity existing to safeguard the interests all pure and traditional breeds of poultry. guardians of the 'british poultry standards', the club has a crucial role in safeguarding stock bloodlines which have been maintained for generations.

many of our members keep poultry purely for pleasure. poultry keeping is a rewarding and valuable experience.

The Poultry Club of Great Britain - Poultry includes chickens, bantams, ducks, geese and turkeys

Preface. The National Farm Animal Care Council (NFACC) Code development process was followed in the development of this Code of Practice.

Factors affecting eggs hatchability

The Code of Practice for the Care and Handling of Hatching Eggs, Breeders, Chickens, and Turkeys replaces its predecessor developed in and published by the Canadian Agri-Food Research Council (CARC).

A Bibliography of Scientific Literature on Fluoride