Native chicken breeding station of Mazandaran was established in 1988 with two main objectives: genetic improvement through selection programs and dissemination of indigenous Mazandarani birds. (Co)variance components and genetic parameters for economically important traits were estimated using (bi) univariate animal models with ASREML procedure in Mazandarani native chicken. The data were from 18 generations of selection (1988-2009). Heritability estimates for body weight at different ages [at hatch (bw1), 8 (bw8), 12 (bw12) weeks of ages and sex maturation (wsm)] ranged from 0.24 ± 0.00 to 0.47 ± 0.01. Heritability for reproductive traits including age at sex maturation (asm); egg number (en); weight of first egg (ew1); average egg weight at 28 (ew28), 30 (ew30), and 32 (ew32) weeks of age; their averages (av); average egg weight for the first 12 weeks of production (ew12); egg mass (em); and egg intensity (eint) varied from 0.16 ± 0.01 to 0.43 ± 0.01. Generally, the magnitudes of heritability for the investigated traits were moderate. However, egg production traits showed smaller heritability compared with growth traits. Genetic correlations among egg weight at different ages were mostly higher than 0.8. On the one hand, body weight at different ages showed positive and relatively moderate genetic correlations with egg weight traits (ew1, ew28, ew30, ew32, ew12, and av) and varied from 0.30 ± 0.03 to 0.59 ± 0.02. On the other hand, low negative genetic correlations were obtained between body weight traits (bw1, bw8, bw12, and wsm) and egg number (en). Also, there is low negative genetic correlation (-24 ± 0.04 to -29 ± 0.05) between egg number and egg weight. Therefore, during simultaneous selection process for both growth and egg production traits, probable reduction in egg production due to low reduction in egg number may be compensated by increases in egg weight.

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The effects of in ovo injected vitamin D 3 source on eggshell temperature ( ET ) and performance of broilers through 14 D of age ( doa ) were investigated. Eggs from a 35-wk-old commercial Ross 708 broiler breeder flock were set in a single-stage incubator with 4 treatments representing each of 12 incubator tray levels (blocks). At 432 h of incubation ( hoi ), noninjected and diluent-injected (50 μL) groups were control treatment groups. Vitamin treatments in the commercial diluent were as follows: 2.4 μg of vitamin D 3 ( D 3 ) or 25-hydroxylcholecalciferol ( 25OHD 3 ). After injection, ET readings were recorded (435, 441, 453, 459, and 465 hoi) by infrared thermometry. Hatchability, hatchling BW, and percentage of male and female hatchlings were determined at 502 hoi. Equal numbers of male and female chicks were placed in each pen and grown out for 14 doa. On a per-pen basis, BW was recorded after hatching at day 7 and 14 doa, and BW gain, average daily BW gain, feed intake ( FI ), and feed conversion ratio ( FCR ) were calculated between 0 to 14 doa. The ET of eggs significantly fluctuated during the postinjection time period; however, the type of vitamin D 3 source injected did not affect ET. Nevertheless, the injection of 25OHD 3 resulted in a lower late embryo mortality than the diluent and D 3 injection treatments. In addition, birds that received 25OHD 3 had a lower FI and FCR than birds in all other treatments. In conclusion, the in ovo injection of 25OHD 3 has the potential to improve early posthatch broiler performance without affecting ET.

Effects of the in ovo administration of vitamin D 3 ( D 3 ) and 25-hydroxyvitamin D 3 ( 25OHD 3 ) on broiler intestinal lesion incidence, performance and breast meat yield after a coccidiosis challenge were investigated. On each of 10 incubator tray levels, 10 Ross 708 broiler hatching eggs were randomly assigned to each of the following 5 in ovo injection treatments administrated at 18 d of incubation ( doi ): 1) noninjected; 2) diluent; diluent containing either 3) 2.4 μg D 3 (D 3 ), 4) 2.4 μg 25OHD 3 (25OHD 3 ), or 5) 2.4 μg D 3 + 2.4 μg 25OHD 3 (D 3 +25OHD 3 ). A 50 μL solution volume was injected into each egg using an Inovoject multi-egg injector. Four male chicks were randomly assigned to each of 80 battery cages in each of 2 rooms. Half of the treatment-replicate cages (8) in each room were challenged with a 20× live coccidial vaccine at 14 d of age ( doa ). One randomly selected bird from each of 4 treatment-replicate cages was scored for coccidiosis lesions before and 2 wk after challenge. Mean BW, BW gain ( BWG) , feed intake, and feed conversion ratio were determined for all birds from 0 to 14, 15 to 28, and 29 to 41 doa. Carcass weight, and the absolute and relative (% of carcass weight) weights of carcass parts were determined in 3 birds per treatment-replicate cage at 42 doa. Hatchability of live embryonated injected eggs and hatch residue were not affected by treatment. Across challenge treatment, birds in the 25OHD 3 treatment group experienced an increase in BWG between 29 and 41 doa when compared to the D 3 or diluent-injected birds. Furthermore, pectoralis major muscle percentage tended ( P = 0.059) to increase in birds belonging to the 25OHD 3 treatment in comparison to birds in the D 3 or diluent-injected treatments. These results indicate that regardless of challenge treatment, 2.4 μg of 25OHD 3 may increase the BWG and breast meat yield of birds relative to those that only received an injection of commercial diluent.

The effects of the in ovo administration of vitamin D 3 ( D 3 ) and its metabolite, 25-hydroxyvitamin D 3 ( 25OHD 3 ) , on the performance, breast meat yield, and inflammatory responses of broilers fed commercial diets were investigated. Live embryonated Ross 708 broiler hatching eggs were randomly assigned to one of the following 5 in ovo injection treatments at 18 d of incubation: 1) noninjected; 2) diluent; diluent containing 3) 2.4-μg D 3 , 4) 2.4-μg 25OHD 3 , or 5) 2.4-μg D 3 + 2.4-μg 25OHD 3 . A 50-μL solution volume of each prespecified treatment was injected into each egg using an Inovoject multiegg injector. At hatch, 18 male chicks were randomly assigned to each of 30 floor pens. The BW, BW gain, feed intake, and feed conversion ratio of the birds were determined in each dietary phase. At 14, 28, and 39 d of posthatch age ( doa ), plasma α-1-acid glycoprotein ( AGP ) levels in 1 bird in each of 6 replicate pens per treatment were determined at 14 and 39 doa. The pectoralis major and minor weights of those same birds were also determined. The remaining birds were processed at 43 doa, and the weights of their processing parts were determined. At 39 doa, the in ovo injection of 25OHD 3 alone decreased plasma AGP concentrations in comparison with the noninjected, diluent, and D 3 -alone treatment groups. In addition, birds that received 25OHD 3 alone had a greater BW at 42 doa than birds in the noninjected, diluent, and D 3 -alone treatment groups. At 39 and 43 doa, breast meat yield was increased in response to the in ovo injection of 25OHD 3 alone in comparison to all other treatments. These results indicate that the in ovo injection of 2.4 μg of 25OHD 3 resulted in an improvement in the performance and inflammatory responses of broilers. A reduction in the inflammatory response subsequent to the in ovo injection of 2.4 μg of 25OHD 3 may have led to an increase in broiler performance.