This work was carried out at Sakha Poultry Production Research Station, Animal Production Research Institute, Ministry of Agriculture, during two successive generations in order to estimate the correlated response in egg production, egg quality and hatch traits to selection for body weight at 12 weeks of age in El-Salam chicken strains. Traits under taken were body weight, egg number, egg weight, egg mass, egg quality, fertility. Heritability, genetic and phenotypic correlations among studied traits were estimated. The means of body weight at 12 week of age in El-Salam chicken strain in the base, first and second generations for males were 868.3, 903.6 and 942.9 g and for females were 838.6, 868.3 and 881.3g for selected line, respectively. Moreover, males and females in the selected line were heavier than corresponding birds in the control one for all generations. After two generations selected for body weight, selected line was significantly higher body weight than control line by 85.4 and 33.6g in average means 9.8% and 4.0% superiority for male and female respectively. Selection to the weight of the body lead to the delayed age at sexual maturity, as well as increased body weight at sexual maturity and the period until the first ten eggs. Means of egg number and feed conversion were significantly reduced by generations. Moreover, egg weight and egg mass for selected line were significantly heavier than those of the control one. As generational succession caused significant improvements on Haugh units, it decreased egg shape index, shell thickens, albumen and yolk percentages. Furthermore, egg shape index and shell percentage were significantly (P<0.05) affected by lines. Also, data showed no significant interactions between generations and lines on all of tested egg quality traits. Reproductive performance as fertility and hatchability percentages were significantly (P≤0.05) reduced by-2.9 vs.-0.6% after progress two generation of selection, but not affected by lines separately or as combination with generations. Heritability estimated for body weight at 12 week of age were 0.67 based on sire variance component (h 2 s). Negative genetic and phenotypic correlations were found between body weight at 12 week of age with egg number, egg mass, fertility, hatchability, egg shape index, yolk%, shell% and shell thickens, while the positive effect were found for body weight at sexual maturity, age at sexual maturity, the period until the first 10 eggs, egg weight, feed conversion, albumen % and Hough unit.

Egg storage longer than 7 days is associated with negative effects on hatchability traits. Pre-storage incubation has been a suggested method to reduce the negative effects of long-term storage times by enhancing the developmental stage of the embryo and probably reducing the embryonic stress. The objective of the present study was to investigate the effects of pre-storage incubation and storage time on hatchability characteristics, chick quality and serum thyroid hormones, antioxidative properties and immunoglobulin Y (IgY) concentrations of newly hatched chicks at two breeder flock ages. A total of 8000 fertile eggs were obtained from two different ages of chicken breeder hens (Egyptian local cross, Inshas). Half of the eggs were collected from young breeder hens (28 weeks old) and the other half from old breeder hens (50 weeks old). In each breeder flock age, eggs were distributed in a completely randomized experimental design in a 2×4 factorial arrangement, with two storage periods (4 or 14 days) and four pre-storage incubation durations (0, 4, 6 or 8 h at 37.5°C). At 28 and 50 weeks of age, pre-storage incubation and its interaction with storage period influenced significantly the apparent fertility, hatchability of set eggs and hatchability of fertile eggs and this improvement in hatchability is attributed to the reduction in embryonic mortality (early, intermediate and late). Pre-storage incubation for 6 or 8 h elevated significantly the grade A chicks and reduced the grade B chicks in comparison with non-heated controls. Interestingly, for eggs stored for 14 days, pre-storage incubation for 6 or 8 h enhanced serum triiodothyronine, thyroxine, glutathione peroxidase activity, total antioxidant capacity and IgY concentrations significantly and decreased serum malondialdehyde concentration significantly in the newly hatched chicks. It could be concluded that pre-storage incubation enhanced the hatching results, improved the antioxidative properties, reduced lipid peroxidation and elevated the humoral immunity in the newly hatched chicks. Hence, several benefits might be gained by pre-storage incubation when fertilized eggs will be stored for long periods.

Simple SummaryThe present investigation examined improvements in egg hatchability and the growth performance of hatched chicks of two strains upon injection with increasing concentrations of royal jelly (RJ). The results showed positive effects of RJ injection on all parameters. Limited impacts of the different chicken strains were observed on the tested parameters. The study revealed that varying the chicken strain could alter the response to the in ovo injection with RJ.AbstractThe hypothesis of the present work was that the effects of in ovo injection may differ in different chicken strains. The influence of in ovo royal jelly (RJ) injection on hatching, growth and blood parameters in two chicken strains (Dokki-4 and El-Salam as example for different strains) was evaluated. A total of 1080 eggs were used. On the seventh day of incubation, the eggs were randomly allocated into six experimental groups in a 2 × 3 arrangement that included the two chicken strains and three concentrations of RJ (0, 0.25 and 0.5 mL RJ/egg). Injection with 0.5 mL RJ/egg improved hatchability compared to the other treatments. The El-Salam strain exhibited significantly higher body weight and body weight gain than the Dokki-4 strain. Injection with 0.5 mL RJ/egg significantly (p < 0.05) improved chicken body weight and daily weight gain compared to the control treatment. RJ injection decreased blood lipid profile parameters and the numbers of monocytes and eosinophils and increased total protein, globulin, haemoglobin (Hb) and lymphocyte levels compared to the control treatment. The Dokki-4 strain showed significantly higher antibody titres against avian influenza virus (AIV) (p < 0.05) and sheep red blood cells (SRBCs) (p < 0.0001) than the El-Salam strain and RJ injection enhanced antibody titres against AIV, Newcastle disease virus (NDV) and SRBCs. Therefore, the Dokki-4 strain was superior to the El-Salam strain for the tested parameters and injection with 0.5 mL RJ/egg produced the best hatching parameters, growth performance and health-related traits. RJ in ovo injection was much more effective in the Dokki-4 strain than in the El-Salam strain, which supported the hypothesis of the study that varying the chicken strain could alter the response to the in ovo injection with RJ.

This work was carried out at Sakha, Poultry Production Research Station, Animal Production Research Institute, Ministry of Agriculture, during three successive generations to study the effect of the individual selection for high body weight at marketing age (12 weeks) on body measurements (shank length, keel length and body circumference), carcass traits (dressing, breast meat, thigh meat percentage, giblets, and offal percentages of live body weight) in El-Salam strain of chicken. Also, estimates of the genetic parameter for these studied traits. A total number of 789 pedigreed birds obtained from 697 dames mated by 92 sires through three successive generations. The chicks in each generation divided into two lines, first is the selected line and second is the control line. The pullets were transferred to individual laying cages until the end of production phase. Artificial insemination was used during the production season by eight females to each male. In base and later generation, checks were selected according to body weight as equal or greater than average of the flock at 12 weeks of age. Number of 36 checks (18 males and 18 females; 6 from each generation) from selected line and 18 checks (9 males and 9 females; 3 from each generation) from the control one at 12 weeks of age were slaughtered to measure the previous carcass traits. Results showed that body weight at 12 weeks of age, increased (p˂0.05) by generations in selected line more than the control line. Also, there were significant differences between generations, lines and sex in body weight and body measurements such as shank length, keel length and body circumference. Selected and unselected males were better than females within and between lines for the most of the studied traits. Chicken males had higher body weight than females in all generations. There were significant differences between generations, lines and sex in carcass traits [dressing, breast meat, thigh meat, giblets (gizzard, heart, and liver) and offal (blood, head, wings, shanks, feather, and viscera) percentages]. Heritability estimates for body weight, shank length, keel length and body circumference at 12 weeks of age were 0.55, 0.44, 0.51 and 0.48, respectively. Heritability estimates for dressing, breast meat, thigh meat, giblets, and offal percentages were 0.48, 0.47, 0.45, 0.52 and 0.47, respectively. All genetic correlations among body weight, body measurements, and carcass traits were positive, ranging from 0.11 to 0.91. All phenotypic correlations between different studied traits were positive ranging between 0.29 and 0.43. It could be concluded that the selection should be carried out to improve body weight, body measurements and carcass traits at marketing age (12 week) in El-Salam strain of chicken in Egypt.

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