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The growth and production performance of a promising three way cross was evaluated under farm and backyard conditions to assess its suitability as backyard chicken variety. The data generated on 200 birds from backyard and 136 birds from farm conditions was analyzed to study the effect of sex on growth and rearing system on growth and production traits. Sex had significant influence on body weights from 6 to 16 weeks of age. Sexual dimorphism was clearly observed in three-way cross with significantly higher body weights in cocks than hens under both farm and backyard conditions. The body weight of male and female birds at 16 weeks of age was 1704.12±16.89 and 1308.22±15.11 g, under farm conditions, while it was 1504.44±32.33 and 962.45±28.22 g, respectively in backyard conditions. Sex had significant effect on the shank length at all ages with longer shanks in males. The laying period body weights were significantly higher in farm reared birds. The type of rearing system significantly influenced age at sexual maturity (ASM), egg weight and egg production till 52 weeks of age. The egg production at 40 and 52 weeks of age was significantly lower in scavenging birds grown in backyard conditions. The ASM was 144.55±1.38 and 198.32±12.23 days in farm and backyard conditions, respectively. The egg production at 52 weeks of age was 146.33±4.41 and 118.40±8.11 eggs in farm and backyard conditions, respectively. The annual egg production (72 weeks of age) was 227.81±6.75 eggs in farm. The study concluded that the better performance of this three-way cross under farm and backyard system with respect to growth and egg production makes it a promising egg type variety for rural poultry farming in the country.

Variance and genetic parameters were estimated for growth and production traits of synthetic broiler female line (PB-2) using REML animal model to delineate the population status, direct additive, maternal genetic, permanent environmental effects, besides genetic trends and performance of economic traits. The overall least squares mean (LSM) for body weights at 0 day (BW0), at 2 weeks (BW2), at 4 weeks (BW4), at 5 weeks (BW5), shank length at 5 weeks (SL5), and breast angle at 5 weeks (BA5) of age were 40.03 g, 207.40 g, 589.58 g, 828.51 g, 76.89 cm, and 80.78°, respectively. The overall LSM for egg production up to 40 weeks of age (EP40) and egg weight at 40 weeks (EW40) were 66.02 eggs and 58.23 g, respectively. The heritability estimates using the best model for BW0, BW2, BW4, BW5, SL5, and BA5 were 0.06 ± 0.03, 0.19 ± 0.03, 0.15 ± 0.03, 0.14 ± 0.02, 0.08 ± 0.02, and 0.02 ± 0.01, respectively. The heritability estimates were low to moderate in the magnitude for all early growth traits. The heritability estimate for egg production up to 40 weeks (EP40) was 0.30 ± 0.05. The heritability estimates for adult body weights at 20 and 40 weeks of age (BW 20 and BW 40), age at sexual maturity (ASM), and egg weight at 40 weeks (EW40) were 0.21 ± 0.04, 0.19 ± 0.04, 0.16 ± 0.03, and 0.33 ± 0.05, respectively, and the estimates were moderate to high in magnitude. Model 4 with additive, maternal permanent environmental, residual, and phenotypic effects was the best model for growth traits except for BW0 and BA5. The average genetic gain observed in primary trait (BW5) over the five generations was 13.62 g per each generation indicating effective selection. The animal model minimized the overestimation of genetic parameters and improved the accuracy of the BV, thus enabling the breeder to select the suitable breeding strategy for genetic improvement.

To evaluate the effect of heat stress an experiment was conducted in which one cross (PB-1X Naked neck), two pure lines ( PB-1 and Naked neck) and corresponding control populations were generated simultaneously on the same day.120 chicks in PB-1X Naked neck (Control 120), 91 chicks in Naked neck pure( Control 82) and 81 chicks in PB-1 pure ( Control 80)were generated. Temperatures were raised (up to 40°C) by providing the two halogen lamps in each of the heat stressed genetic groups from 4-6 weeks of age. Body weights were recorded at 0, 2,4, 6 and 7 weeks of age along with conformational traits like breast angle and shank length at 6 weeks of age. 2ml of blood was collected at 6weeks of age from all the 6 genetic groups (10 birds from each) to estimate the heat stress parameters. Feed efficiency was recorded at 6 weeks and 7 weeks of age. Significant differences were found for SOD, CAT, ALP and GPx between heat stressed and control genetic groups. Higher estimates were found in heat stressed genetic groups as compared to corresponding control groups. For juvenile body weights in stressful conditions there is significant difference between genetic groups. Lower juvenile body weights were recorded in heat stressed genetic groups as compared to control groups. Lower feed efficiency was recorded in heat stressed genetic groups as compared to corresponding control groups.

A study was conducted to assess genetic heterogeneity among 14 chicken populations using 16 microsatellite markers. All the microsatellite loci except MCW048 were polymorphic. The number of alleles varied from 2 to 6. The polymorphic information content of the microsatellite markers varied from 0.21 to 0.87. The average observed number of alleles across the microsatellites varied from 3 to 3.8, while effective number of alleles varied from 1.9 to 3.0. The average observed and expected heterozygosities were in the range of 0.3–0.6 and 0.4–0.6, respectively. The markers, MCW049, MCW044, MCW041, ADL176, MCW059, ADL136 and MCW110 showed heterozygosity excess and ADL158, MCW043, ADL102, MCW014, ADL023, ADL210 and MCW007 markers revealed heterozygosity deficiency in the populations. The genetic distance between layer and broiler lines was found to be high ranging from 0.22 to 0.38. The Indigenous populations were more closely related to broiler lines than layer ones. In conclusion, it is stated that Indigenous,...

Coloured broiler breeders are becoming popular in recent years because of the preference for a range of poultry products as well as the welfare issues in the poultry industry. The female broiler breeders are continuously improved for various economic traits. Amongst these, egg quality trait is very essential for the production of healthy and viable chicks. This study investigates the egg quality parameters in a synthetic coloured broiler breeder female line at different age groups. The study revealed that the egg quality is optimum for setting the eggs for hatching from 40 week onwards as the egg size and internal egg parameters attain the minimum standards for the production of a healthy chick.

The pituitary hormone prolactin has a wide variety of functions involving growth, behavioral, and ovarian activities in chickens. The objectives of the present study were to identify polymorphisms in the prolactin promoter and estimate their effects on growth traits in White Leghorn chickens. Among 28 haplotypes found, the h1 haplotype was predominant. Body weight at 16 and 64 weeks and age at sexual maturity were significantly associated with haplotype combinations (P < 0.05). The h1/h1 haplogroup showed the highest body weight at 16 weeks of age, and h1/h7 was the highest at 64 weeks. The lowest age at sexual maturity was found in birds with the h1/h6 haplotype combination, and mRNA expression of prolactin was lowest in h1/h4 birds and highest in h1/h5 birds. The prolactin promoter was highly polymorphic and had significant associations with growth traits in White Leghorn chickens.

A comprehensive study was undertaken to evaluate the effect of naked neck (Na) gene on immune competence, serum biochemical parameters and carcass quality traits in three genotypes (NaNa, Nana and nana) of the naked neck chicken under a tropical climate (Southern India). Sixty day-old chicks (20 from each genotype) were selected randomly and reared under similar environmental conditions up to eight weeks of age. The cell mediated immune (CMI) response to phytohaemoagglutinin-P (PHA-P) was significantly higher (p≤0.01) in NaNa and Nana genotypes compared to nana birds. The humoral response as measured by antibody titre to sheep red blood cells (SRBC) was also significantly higher in NaNa. The total cholesterol, LDL and VLDL cholesterol levels were significantly (p≤0.01) lower whereas HDL cholesterol level was significantly higher in NaNa and Nana compared to nana genotype. The presence of Na allele significantly increased the live weight and dressing yield, and decreased the feather cover and abdominal fat. The naked neck genotypes (NaNa/Nana) performed better than the normal (nana) siblings for almost all the traits studied.

A comprehensive study was undertaken to evaluate the egg quality traits in three naked neck genotypes, NaNa (homozygous), Nana (heterozygous) and nana (normal) by utilizing 556 eggs collected at 28, 32, 36 and 40 weeks of age. The overall mean egg weight, shape index and Haugh unit values were 56.41 g, 75.79 and 75.98, respectively. The yolk index, yolk height and yolk colour varied significantly (p

The data of G-5 generation of inbred and non-inbred populations of Dahlem Red were utilized in the present study. These populations were originally developed by a regular system of full sib and half sib mating for 5 successive generations. A random mated non-inbred population was also maintained. Consequently, 3 sub populations have been developed from the same base population, namely, a full sib mated group (FS), a half sib mated group (HS) and a non-inbred group (NB). The inbreeding coefficient in the G-5 generation in the FS group and HS groups was 67.2% and 44.9%, respectively. These three sub populations were subjected to PCR-RAPD analysis to observe the genetic distance and similarity between different subpopulations. A total of 41 random primers (decamers) were screened for RAPD analysis, out of which 21 primers amplified the genomic DNA, generated 128 to 4544 bp bands. The Mean Average Percentage Difference (MAPD) varied between 13.22 and 22.20. The MAPD was highest between FS and NB and lowest between HS and FS. The intra-population genetic similarity was highest in FS (0.7139) followed by HS (0.7095) and NB (0.7054) which indicated that FS subpopulation is most uniform. The FS and NB had maximum genetic distance (by both band sharing and band frequency) and FS and HS had lowest genetic distance. The immune response to SRBC was highest in NB group followed by FS and HS groups.

An experiment was conducted to elucidate the effect of graded levels of vitamin D 3 in White Leghorn (WL) layer breeders on egg production, shell quality, hatchability of eggs and juvenile performance of offspring during their late laying period (72-88 wk). White Leghorn breeder females were randomly divided into 5 groups of 50 each and were housed in individual California cages in an open-side housing system. Considering birds in five cages as a replicate, 10 such replicates were randomly allotted to each treatment. A basal diet was formulated containing all the nutrients as recommended for WL layers except vitamin D 3 , which served as control. Another, four diets were formulated by supplementing graded levels of feed grade crystalline cholecalciferol to the basal diet that contained 300, 600, 1,200 and 2,400 ICU of vitamin D 3 per kg. Each diet was offered ad libitum to one of the above five treatment groups. The egg production, egg weight, daily feed consumption and the feed intake per dozen eggs or kg egg mass of the birds fed diet without any supplemental vitamin D 3 was comparable with those of supplemental groups. Similarly, the level of vitamin in the diet did not have any effect on any of the above parameters. However, the specific gravity of eggs laid by the birds fed the diet without supplemental vitamin D 3 was comparable with either 600 or 2,400 ICU supplemental groups but significantly higher when compared to the 300 and 1,200 ICU groups. The egg -shell breaking strength was significantly lowered in the 600 ICU supplemental groups as compared to the strength of other dietary groups. The Haugh unit, egg shell weight, shell thickness, tibia breaking strength, bone ash and calcium content were not influenced by vitamin D 3 concentration in the diet. Serum Ca concentration was influenced by vitamin D 3 level in the diet. The serum Ca concentration of birds fed either control or the vitamin supplemented diet up to 1200 ICU/kg diet was comparable. However, increasing the concentration of vitamin D 3 to 2,400 ICU/kg diet significantly enhanced the concentration of Ca in the serum, which was significantly higher compared to other dietary groups. The serum concentration of P and protein, however, was not influenced by level of vitamin D 3 in the diet. Neither fertility nor hatchability was influenced by vitamin D 3 concentration in the diet. Feeding a vitamin D 3 deficient diet or supplementation of vitamin to hens did not have any influence on their progeny chicks. It can be concluded that dietary supplementation of vitamin D 3 may not be essential for optimum production, shell quality, hatchability, and juvenile performance of WL breeders during 72 to 88 weeks of age.

Expression of prolactin hormone is a crucial event in regulating egg production in chickens for which promoter plays the vital role in expressing the prolactin gene. The objective of the present study was to identify haplotypes in the prolactin promoter and their effects on egg production and egg quality traits in White Leghorn chicken. Single stranded conformation polymorphism followed by sequencing was conducted to explore polymorphism at 561 bp promoter of prolactin gene. The effect of haplotype combinations on egg production and quality traits were estimated following general linear model technique. The expression of prolactin by different haplogroups was quantified by qPCR. Total 28 haplotypes were found in White Leghorn chicken of which h1 haplotype possessed the highest frequency of 0.46 and h8, h14, h16, h25, h26, and h28 haplotypes had the lowest frequency (0.1%). The egg production up to 52 and 64 weeks of age were found to be significantly (p < 0.05) associated with haplotype combinations where the highest 52-w (52 weeks) egg production was found in animals with h1/h22 combination and the lowest production was observed in the birds with h1/h2 haplogroup. The haplotype combinations had the significant effect (p < 0.05) on Haugh Unit, yolk index and albumen weight at 40 weeks of age; Haugh Unit and albumen weight at 52 weeks of age and Haugh unit, yolk weight and yolk percentage at 64 weeks of age. The prolactin expression in h1/h22 birds was found to be the lowest and in h1/h5 birds to be the highest. The prolactin expression showed significant effect on 52-w egg production and albumin weight at 52 weeks age. In conclusion, it may be stated that the prolactin promoter was highly polymorphic and had the significant association with egg production and quality traits in White Leghorn chicken.