NOWACZEWSKI S., KONTECKA H., KRYSTIANIAK S. 2012. Effect of In Ovo injection of vitamin C during incubation on hatchability of chickens and ducks. Folia biologica (Kraków) 60: 93-97. The aim of the investigation was to ascertain the influence of different doses of vitamin C injected at selected dates of incubation into the eggs of broiler breeders and Pekin ducks on hatchability. The injected vitamin C doses were administered into the air cell on the 13 JD , 15 JD and 17 JD days (3 and 6 mg chickens) and on the 12 JD and 20 JD days (4 and 8 mg ducks) of incubation. In the case of chickens, no significant differences were recorded between the control and experimental groups with regard to hatchability, although the highest value of hatchability from fertilized eggs was determined in the group injected with 6 mg of vitamin C on the 15 JD day of incubation. On the other hand, in ducks, significant differences were found between the control and experimental groups (4 mg of vitamin C administered on days 12 and 20 and 8 mg of vitamin C injected on day 20 of incubation) regarding hatchability. The value of this trait was higher in the group of eggs injected with ascorbic acid in comparison with the eggs which were not treated. On average, the difference amounted to 32.5 percentage points. Similarly, in the case of the number of dead embryos and unhatched chicks, better results were observed in the above-mentioned experimental groups. In summary, vitamin C injected into chicken eggs failed to influence hatchability. In the case of duck eggs, it was demonstrated that their injection on the 20 JD day of incubation with selected doses of vitamin C (4 and 8 mg/egg) improved hatchability by decreasing the proportions of dead and unhatched embryos.

Abstract. The aim of the performed investigations was to compare eggs of Japanese quail layers of different weights with regard to their shape, selected traits of the content following various times of their storage as well as the results of hatchability and body weight of one-day old chicks. Hatching eggs were divided into four groups: group S – up to 10.50 g, group M – from 10.51 to 11.50 g, group L – from 11.51 to 12.50 g and group XL – from 12.51 g. In experiment I, on days: 1, 3, 5, 7 and 10 of storage, the following traits were assessed in 20 eggs from each group: egg weight (g) and yolk and albumen index as well as the number of Haugh units. In experiment II, five hatches were carried out. The total of 480 eggs were incubated in each hatch (120 eggs for each group). On the 15th day of incubation, the eggs were weighed. After hatching, 30 chicks from each group were weighed. Basic hatchability indices were also determined. Eggs with the smallest weight, stored for 1 day, with the smallest yolks were characterized by their highest content contrary to the eggs with the highest weight (the biggest yolks but with their smallest percentage content). In eggs with the higher weight (groups L and XL), a certain increase in weight and proportion (%) of yolk was observed after 3, 5, 7 and 10 days. The highest albumen percentage content was determined in eggs from groups L and XL, whereas in the remaining groups the albumen content was the smallest. With the lengthening of the egg storage, the albumen weight did not undergo significant changes. After one-day storage, the yolk and albumen index as well as Haugh units were slightly higher for eggs of smaller weight than for bigger ones. Eggs from groups S and M were more spherical. Eggs from groups L and XL had smaller weight losses during hatching. Eggs from group L were characterized by the best fertilization, hatchability results and proportion of dead embryos and unhatched chicks. The heaviest chicks were obtained from eggs of the highest weight, while the lightest – from eggs of the smallest weight. The obtained results appear to indicate that Japanese quail eggs of 10.51-12.50 g are the best for hatching.

The aim of the study was to assess laying traits, the weight of eggs and characters of the laying rhythm of pheasants in the first and second years of reproduction. Pheasants (10 cockerels and 50 hens) were kept in aviaries. Daily, individual control of laying was performed beginning with the day of the first laying and ending with the last egg. The following parameters were evaluated: age at first laying, length of the laying period, number of laid eggs and the average weight of the egg in the 8 th week of laying. The laying rhythm was also assessed and comprised: the number of egg clutches, the number of eggs in a clutch, the number of eggs in the longest clutch, the number of intervals, the length of intervals and the longest interval between clutches. During the first period of reproduction, in comparison with the second, pheasants laid slightly more eggs of similar average weight. The first laying period was longer than the second and was characterised by a greater number of egg clutches and greater number of intervals between clutches. The greatest number of eggs was laid in 10-egg and longer clutches, although the 1-egg clutches were the most numerous. A positive correlation was found between the number of eggs and the number of clutches, the greatest number of eggs in a clutch and the number of intervals between clutches. The similar values of the reproductive characters of one-and two-year old pheasants point to the possibility of longer utilization of these birds than only for one laying period. On the other hand, the considerable variability between the experimental hens with regard to the number and the length of egg clutches, as well as the intervals between them, indicate the possibility to carry out selection taking into account traits characterising the laying rhythm.

A comparative analysis of reproduction parameters and hatchability results of pheasants raised under two different housing systems (cages and aviaries) was performed. In the first system the pheasants were housed in 420 cages, 3780 from the total were females. In the second housing system, 3200 pheasant hens were placed in eight aviaries, where 50 cocks and 400 hens were kept in each. The following parameters were calculated: laying rate, the percentage of hatching, small and cracked eggs, hatchability from set and fertilized eggs, dead embryos up to day 8 of incubation and, finally, dead embryos after day 8 of incubation as well as unhatched, crippled, and weak chicks. The laying rate for the whole period of reproduction in pheasants kept in cages was significantly higher in comparison with aviaries (59.6 vs 27.2%). A higher (P ≤ 0.05) percentage of small and damaged eggs ( -x = 13.6) was recorded in aviaries. The percentage of dead embryos for eggs derived from aviaries, up to day 8 of incubation, was also significantly higher ( -x = 4.7%). There were no significant differences between the housing systems with respect to the remaining features. The results of the investigation made it possible to conclude that pheasants kept in cages were characterized by a higher laying performance with fewer eggs unsuitable for incubation. A lower mortality of embryos during the incubation process was found in eggs derived from pheasants reared in cages. Although there were no significant differences between the analyzed housing systems in terms of hatchability, a higher laying rate for pheasants kept in cages implies that more chicks could be obtained from every female.

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