Results and discussion
EXPERIMENT 1
Body weight:
Genotype by sex interaction was found to be highly significant at 6 and 18 wk of age, significant at 3, 15 and 21 wk of age and not significant at 9 and 12 wk of age (Table 1,2). The different among genotype were examined within each sex. Significant difference were found between the two sexes at all studied ages (Table 1). For the pure breeds, FF had the heaviest body weight at 3, 6 and 9 wk of age for males, and 3, 9 and 12 wk of age for females, while RR had the heaviest body weight at 12, 15, 18 and 21 wk of age in males and 6, 15, 18 and 21 wk of age for females. There were no significant differences between RR and LL males at 6 wk of age and at 3, 12, 15, 18 and 21 wk of age for females. DD showed the lighest body weight for both sexes at all studied ages. There were no significant differences between DD and SS at 9, 15, 18 and 21 wk of age in males while significant differences were found in females.
For crosses, generally 25% FF crosses were heavier than other crosses. It seems that the reseason of getting such result is that FF breed used in this study was selected for heavier body weight at 8 wk of ages for many generation (Hossari, 1970). Generally, in males (Table 3)of the crosses the LFS had the heaviest body weight than all studied crosses at 3 and 12 wk of age, cross RFL had the heaviest body weight at 6 and 9 wk of age, cross RDL at 15 and 18 wk of age and cross SRL at 21 wk of age in males. In females (Table 4) LFS had the heaviest body weight at 3 wk of age, cross RDS at 6, 9, 12 and 15 wk of age and cross RLF at 18 and 21 wk of age.
These results are in agreement what found by Abd EL-Ghany 1995, who reported that RR had highter body Weight compared with FF, LL, SS and DD. In addition Hassan 1973, found that Fayoumi crosses gave heavier one-day old chicks than Fayoumi. The signiffecant differences between the tow sexes are in agreement with that found by Kenpster 1941, Mondonedo 1950, Halag et al. 1962, Negm et al. 1982, and Osman et al. 1992.
Growth rate.
Significant genotype by sex interaction was found for growth rate at all studied ages (Table 5 and 6). Significant differences in growth rate were observed among studied genotypes at all studied ages, except at 3 to 6, 6 to 9 in both sexes and 15 to 18 wk of age in females. With respect to the pure breeds, RR males (Table 7) had significantly the highest growth rate from 9 to 12 wk of age of all pure breed males. In female crosses LRF had the highest growth rate from 9 to 12 wk of age (Table 8). From 12 to 15 wk of age DD had the highest growth rate, while FF had the lowest in both sexes. In crosses LFR had the highest growth rate in males, while LRF showed the highest in females. From 18 to 21 wk of age LL had the highest growth rate in males and no significant difference was found between it and RR, FF and DD, while SS had the lowest growth rate. In female From 18 to 21 wk of age in five pure breeds LL had the highest growth rate and SS had the lowest one, in crosses RFL had the heaviest growth rate and no significant difference was found between it and both RDS and LFR. In general, no fixed trend for the significant among all genotypes in growth rate for both sexes.
Growth rate decreased by increasing of age these results are in agreement with what reported by Asmundson and Larner 1934, Parker 1943, Rajartnam et al. 1971, Mostageer et al. 1975, Hassan et al. 1976, Abd El-Galil 1977, Marks 1979, Shawer et al. 1980, Shawer 1984, and Kalil 1993.
Heterosis of body weight.
Significant differences were found between the two sexes at 3, 6, 9, 12 and 15 wk of age, while no significant differences were found between the two sexes at 18 and 21 wk of age (Table 9 and 10). In males (Table 11) at 3 wk of age cross SRL showed the highest heterosis over other crosses while the cross LRF had the lowest heterosis, In females (Table 12) RDS showed the highest heterosis and RLD showed the lowest one.
In males at 6 and 9 wk of age cross RFL showed the highest heterosis over other crosses while the cross LRF had the lowest heterosis, In females RDS showed the highest heterosis and RLD showed the lowest one.
In males at 12 and 15 wk of age cross LFS showed the
highest heterosis than other crosses while the cross LRF had the lowest
heterosis, In females RDS showed the highest heterosis and RSL and RLF showed
the lowest heterosis at 12 and 15 wk of age, espectively.
Amer et al. 1973, Hanfi et al. 1977, Sharma 1978, Singh et al. 1982 and Ayoub 1986, reported heterosis effect in body weight when crossing local breeds with exotic breeds.
Sexual maturity and egg production.
Age at sexual maturity:
Analysis of variance of the data showed highly significant differences among genotypes in age at first egg (Table 13). For the pure breeds (Table 15) SS breed was the first to reach sexual maturity (173.53 day), while RR was the latest breed to reach sexual maturity (181.55 day). In crosses, RDS was the first cross to reach sexual maturity (147.33 day) followed by RLF (157.93 day), while RFL reached sexual maturity later than the other genotypes (194.60 day).
Body weight at sexual maturity:
There were highly significant differences in body weight at sexual maturity among different genotypes (Table 13). The cross SRL had the heaviest body weight at sexual maturity (1548 g) of all genotype. This resultes gives an indication of a heterosis in this trait. For the pure breeds RR had the heaviest body weight at sexual maturity (1537.27 g) and DD had the lightest one (1107.65 g).
The significant differences among genotypes in both age and body weight at sexual maturity are in were agreement with that which reported by Hassan 1973, Shrara 1974, Abo El-Kasem 1977, El-Turky 1981, Elham et al. 1981, and Abd EL-Ghany 1995.
Shank length:
There were highly significant differences among genotypes in shank length (Table 13). Shank length for pure breeds ranged from 8.83 cm (for DD) and 9.71 cm (for RR). The cross SRL showed the longest shank length of all studied genotype (9.8 cm), which is an indication of heterosis.
The SRL recorded the highest score for body weight and shank length at sexual maturity, while DD breed recorded the lowest score for these two traits. These data suggested a correlation between the tow traits (body weight and shank length at sexual maturity).
Keel length:
Highly significant differences among genotypes were found in keel length (Table 13). In the pure breeds FF (10.62 cm) had the longest keel length and DD had the shortest one (9.40 cm). The cross RFL showed the longest keel of all studied genotypes (11.20 cm).
Comb hight:
Analysis of variance of the data showed highly significant differences among genotypes in comb hight at age of sexual maturity (Table 13). LL had the highest comb (3.53 cm) and DD had the shortest one (1.95 cm). The cross RLF showed the highest comb of all studied crosses (3.27 cm).
Comb length:
There were highly significant differences among genotypes in comb length (Table 13). The LL had the longest comb (3.71 cm) and DD had the shortest one (2.46 cm). The cross RLF as in comb hight showed the highest comb of all studied crosses (3.44 cm), which suggest a heterosis in comb length and a correlation between comb hight and comb length.
Wattle length:
There were highly significant differences among genotypes in wattle length (Table 13). In five pure breeds LL (2.20 cm) had the longest wattle length and DD (1.54 cm)had the shortest one. For crosses RDS had the longest wattle (2.50 cm) and SRL had the shortest one (1.56 cm). The crosses wattel length values indicated a heterosis in this trait.
Generaly analysis of variance of the data showed significant differences between the genotypes in body measurment at sexual maturity. These resultes are in agreement with that reported by El-Wardany et al. 1994, Abd El-Gawad et al. 1979. Sabra 1990, Zelenka et al. 1986 and Sabri 1993.
90 and 120 day egg number:
There were no significant differences among genotypes in 90-day egg production (Table 14). However, there were significant differences (p£ 0.05) among genotypes in 120-day egg production (Table 14). For the pure breeds White Leghorn (Table 16)had the highest egg production (81.9 eggs) and DD had the lowest one (61.82 eggs). For crosses, RDF had the highest one (80.89 eggs) and RFL had the lowest one (61.60 eggs).
The intermediate values for crosses egg number suggested an additive effect in this trait.
90 and 120-day egg weight:
Although there were no significant differences among genotypes in 90-day egg number, the differences were highly significant in 120-day egg weight (Table 26). This could be du to differences in body weight among genotypes since body weight and egg weight are correlated. RR had the biggest egg (47.29 g) and DD had the smallest one (36.94 g). The crosses values were intermediate among the pure breed values, .However, reported a heterosis in this trait.
There were highly significant differences among genotypes in these tow traits (Table 14). RR had the biggest egg ( 48.6 g) and DD (37.65 g) had the smallest one (Table 16).
90 and 120-day egg mass:
Egg mass is a function of both egg weight and egg number. The analysis of variance of the data showed highly significant differences among genotypes in 90-day egg mass (Table 14). LL (2870.00 g) had the highest egg mass, while DD (1848.44 g) had the lowest one (Table 16).
The analysis of variance of the data showed highly significant differences among genotypes in 120-day egg mass. As in 90 day egg mass LL had the highest egg mass (3807.44 g) and DD had the lowest one (2349.09 g). There were significant differences in egg number, weight and mass among genotypes, these resultes are in agreement with that showed by El-Itrbi et al. 1963, Hassan et al. 1976, Hassan et al. 1981, El-Turky 1981, Aly 1993 and Merat 1994.
Heterosis estimates
Heterosis of sexual maturity traits:
A wide range of body weight heterosis at sexual maturity was observed (Table 19). While, the cross SRL had the highest heterosis (203.3 g), the cross LFR had the smallest one (225.9 g).
The cross RFL had the highest heterosis for age at sexual maturity and the cross RDS had the smallest one. A reduction in sexual maturity age was noticed for crosses, wherer eleven crosses out of sixten showed a negative heterotic effect. The data showed difference in hetrosis of both age and weight at sexual maturity. These resultes are in agreement with what reported by Kosba et al. 1977, Kosba 1978, Mahmoud et al. 1980 and Shawer et al. 1981.
The cross RDF (Table 19) had the highest heterosis in 90 and 120-egg number (7.45 and 13.11 eggs, respectively), and 90 and 120-day egg masses (197.23 and 428.77 g , respectively). The cross RFL had the smallest one, in both 90 and 120 egg number ( -9.38 and -10.98 eggs, respectively) and 90 and 120-day egg masses (-543.61 and -649.33 g, respectively).
The cross SRL had the highest heterosis of 90 and 120-day egg weight (2.59 and 2.69 g, respectively), and the cross RDS had the smallest one, in both 90 and 120 egg weight (-4.58 and -4.09 g, respectively).
Correlation estimates:
Correlation estimates between body weights:
High genetic correlation was estimated between 6 wk body weight and each of 12 and 18 wk body weights. This resultes suggest that 6 wk body weight can be used as indirect selection for improving 12 and 18 wk body weight. The highest phenotypic correlation was estimated between 3 and 18 wk of age (Table 20). The positive genetic and phenotypic correlation between body weight at different ages are in agreement with that which found by Merrit 1966, El-Hossari et al. 1970, Sabri 1979, Sabri 1993, and Ezzeldin 1991.
Correlation estimates among egg production and sexual maturity traits:
The highest genetic correlation was estimated between egg weight and egg mass, between shank length and sexual weight and between wattle and both comb hight and comb length (Table 39).
The highest phenotypic correlation was estimated between 90 and 120 day egg Weight. The lowest were estimated between age at sexual maturity and 120-day egg number(Table 21).
The correlation between egg number and egg weight varied from positive to negative. These resultes are in agreement with Yoo et al. 1981. The negative correlation between age and weight at sexual maturity, egg number and egg mass are in agreement with Sheble 1991. The positive correlation between body weight at Sexual maturity and both shank and keel length are in agreement with El-Turki 1981. The highly correlation between most of body measurment and egg production traites are in agreement with what reported by Sabri 1993 and Aly 1993.
Heritability estimates:
Heritability estimates for body weight:
The highest heritability was estimate for 3 wk of age body weight and the lowest one was estimated for 18 wk body weight. The heritability which estimates from dam component was highter than that which estimates from sire component these resultes are in agreement with Shalash 1977 and in disagreement with Rishel et al. 1973. The heritability which estimates for hatch weigth were positive and higher than those of other different ages, these resultes are in agreement with that found by Sabri 1979 and in disagreement with Eid 1979.
Heritability estimates for egg production and sexual maturity:
The highest heritability was estimate for 120 day egg weight and the lowest one was estimated for 90 day egg number (Table 21).
EXPERIMENT 2:
Body weight:
significant difference was found in the sex by genotype interaction (Table 22 and 23) an indication that the differences among genotypes are not the same for both sexes. For the pure breeds males, RR had the heaviest body weight at 3, 15, 18 and 21 wk of age and FF had the heaviest one at 6, 9 and 12 wk of age (Table 24). In females (Table 25)RR had the heaviest body weight at all studied ages except at hatch. At hatch LL showed the heaviest body weight for both sex. Hatch weight is known to be a function of egg weight. In both males and females DD had the lightest body weight at all studied ages.
For crosses, FRDL and FRLD had the heaviest body weight at all studied ages in both male and females with superiority for FRLD at later ages. The 50% DD crosses namely DRSL, DLFS, DLSR and DSRL were in general the lightest crosses in both sexes.
Growth rate.
There were significant interaction in growth rate between studied genotypes and sex (Table 26 and 27). For the pure breeds, from 0-3 and 3-6 wk of age FF had the highest growth rate in both males and females, in crosses FRLD had the highest growth rate than all studied genotypes and no significant differences was found between it and FRDL in males.
No specific trend could be identified among genotypes within sex for growth rate.
Heterosis of body weight.
Heterosis of body weight at hatch:
Significant interaction was found between genotype and sex, an indication of different heterosis magnitude among genotype within the tow sexes. The 50% FF crosses showed the highest heterosis especially FRLD. However, the 50% SS and 50% DD showed the the lowest heterosis (Table 32 and 33). these results is expected from the body weight results (Table 24 and 25). The 50% RR and 50% LL crosses were intermediate in their heterosis.
Sexual maturity and egg production.
Age at sexual maturity:
Sexual maturity traits were studied on females only. Analysis of variance of the data showed highly significant differences among genotypes in age at first egg (Table 34). Although age at sexual maturity for the pure breeds ranged from 155.77 days(for FF) to 167.21 days (for DD), the crosses ranged from 150.65 days (for SLFR) to 170.70 days (for DSRL). In general 50% DD crosses and 50% LL crosses were the oldest at firest egg (Table 36).
Body weight at sexual maturity:
There were highly significant differences in body weight at sexual maturity among different genotypes (Table 34). While the pure breeds (Table 36) ranged from 1524.28 g (for RR) to 1213.00 g (for DD), the crosses ranged from 1537.00 g (for FRDL) to 1252.34 g (for DLSR). In general, 50% FF, RR and LL were the heaviest crosses and 50% SS and DD were the lightest .
Shank and kell length:
Highly significant differences in shank length at sexual maturity were found among different genotypes (Table 34). In pure breeds (Table 36) DD had the shortest shank and keel (8.7 and 9.19 cm, respectively) and LL had the longest shank and keel (9.52 and 10.54 cm, respectively). In crosses (Table 36) cross FRLD had the longest shank and keel (9.66 and 10.96 cm, respectively) and the cross DSRL had the shortest shank (8.74 cm) and the cross DLSR had the shortest keel (9.38 cm).
In both keel and shank lengths at sexual maturity we showed that DD had the shortest keel and shank, thse traits were found to be correlated by Ragab et al. 1956, Chabra et al. 1972, and Shalash 1977.
Comb hight and length:
Analysis of variance of the data showed highly significant differences among genotypes in both comb hight and length at age at sexual maturity (Table 34). In pure breeds LL had the highest comb and longest comb (3.60 and 6.14 cm, respectively), DD had the lowest comb and shortest comb (2.50 and 3.82 cm, respectively). and SLRF had the lowest one (2.16 cm). In crosses, FRLD had the highest comb (3.51 cm) and SRFL had the longest comb (6.21 cm) and SLRF had the lowest comb and shortest comb (2.16, and 3.43 cm, respectively).
Wattle length:
Highly significant differences in wattle length at age at sexual maturity were found among different genotypes (Table 34). In pure breeds (Table 36) LL had the longest wattle (2.34 cm) and SS had the shortest one (1.24 cm). In crosses, FRDL had the longest wattle (2.12 cm) and LRSF had the shortest wattle (1.38 cm).
90 and 120-day egg number:
No significant differences among genotypes in 90-day egg number, but there were highly significant differences among genotypes in 120-day egg number (Table 35). There were no significant different among pure breeds in 120-day egg number (Table 37), the number of egg ranged from 73.10 egg (for DD) to 69.52 (for SS). The cross DRSL had the highest egg number (73.69 egg) and SRLF had the lowest one ( 67.12 egg ).
90 and 120-day egg weight:
Highly significant were found in both 90 and 120-day egg weight (Table 35). In pure breeds (Table 37)RR had the biggest egg in both 90 and 120-day egg weight ( 45.52 and 47.51 g, respecively) and FF had the smallest one ( 38.01 and 40.03 g, respectively). In crosses, FRLD had the bigest egg in both 90 and 120-day egg weight (45.25 and 47.89 g, respectively) and SLRF had the smallest one (39.28 and 41.81 g, respectively).
90 and 120-day egg mass:
90 and 120-day egg mass showed highly significant differences among genotypes (Table 35). In pure breed (Table 37)RR had the highest 90 and 120-day egg mass( 2431.54 and 3310.98 g, respectively) and SS had the lowest one (2069.77 and 2797.93 g, respectivly). The cross FLRD had the highest 90 and 120-day egg mass ( 2436 and 3333.69 g, respectively) and SRLF had the lowest one (2134.34 and 2889.56 g, respectively).
Heterosis estimates for egg production and sexual maturity traits:
Significant differences were found between crosses in body weight and age at sexual maturity (Table 38). The cross FRDL had the highest heterosis for sexual maturity weight and DLSR had the smallest one (Table 40).
The cross SLRF had the highest heterosis for age at sexual maturity and the cross SLFR had the smallest one (Table 40).
In both 90 and 120-day egg number traits cross SLFR had the highest heterosis and the cross RLSD had the smallest one (Table 40).
In both 90 and 120-day egg weight traits cross FRLD had the highest heterosis and the cross SLRF had the smallest one (Table 40).
In both 90 and 120-day egg mass traits cross FLRD had the highest heterosis and the cross RLSD had the smallest one (Table 40).
Correlation estimates:
Correlation estimates among body weights:
The highest genetic correlation was estimated between 9 and 12 wk of age and that which estimated between 12 wk 18 wk of age, and the lowest one was estimated between 0 and 12 wk of age (Table 38). The highest phenotypic correlation was estimated between 18 wk and 21 wk of age and the lowest were estimated between 0 and 12 wk of age (Table 41).
Correlation estimates among egg production and sexual maturity:
The highest genetic correlation was estimated between Keel length and shank length and between 90 and 120 day egg Weight. The lowest genetic correlation were estimated between wattle and both 90 and 120 egg weight (Table 42).
The highest phenotypic correlation was estimated between 90 and 120 day egg Weight. The lowest were estimated between sexual age and 120 day egg weight (Table 42).
Heritability estimates:
Heritability estimates for body weight:
From sire component the highest heritability was estimated for 6 wk body weight and the lowest one was estimated for 3 wk body weight. From dam component the highest heritability was estimated for hatch body weight and the lowest one was estimated for 12 wk body weight. From dam + sire component the highest heritability was estimated for hatch body weight and the lowest one was estimated for 12 wk body weight (Table 43).
Heritability estimates for egg production and sexual maturity:
From sire component the highest heritability was estimated for sexual age and the lowest one was estimated for comb length. From dam component the highest heritability was estimated for sexual weight and the lowest one was estimated for 120 day egg mass. From dam + sire component the highest heritability was estimated for sexual age and the lowest one was estimated for comb length (Table 44).