Hatch Weight Research Articles

Factors influencing the embryonic development and hatchling size of the oceanic squid Illex coindetii following in vitro fertilization

Egg masses of oceanic squid accidently collected in the wild have been observed only from a few spawning events in aquaria, and as a consequence, the study of their embryos and hatchlings is very limited. Here, we used in vitro fertilization techniques to understand the abiotic factors that influenced egg development and hatchling performance of the ommastrephid squid Illex coindetii from the Mediterranean Sea. Egg and hatchling sizes of these ommastrephids are close to the minimum for cephalopod species, and therefore, short embryonic developmental periods were expected under a Mediterranean temperature regime. Low incubation densities and the use of antibiotics in the incubation medium resulted in relatively high survival rates to hatchling. Hatching time was inversely proportional to incubation temperature and ranged from 5 to 11days at 21°C and 13°C, respectively. The addition of oviducal jelly to the eggs immediately after fertilization, followed by another addition at the beginning of organogenesis, resulted in better chorionic expansion, with an increase in egg diameter, delayed hatching and higher hatchling weight, which suggests a better use of yolk reserves. Larger hatchlings in length and weight also tended to be produced at low temperature, probably also due to better yolk absorption. As this species spawns all year round, size differences between summer and winter hatchlings may be suspected. In vitro fertilization techniques used in the laboratory proved to be useful in shedding some light on the early life of this oceanic squid. Further research is needed to elaborate on tests to predict gamete quality and to develop methods to avoid premature hatching.

Nesting Density is an Important Factor Affecting Chick Growth and Survival in the Herring Gull

Abstract. The causes and consequences of coloniality in seabirds, and larids in particular, have received extensive study. Here, we use the Herring Gull (Larus argentatus) as a model organism to investigate the effect of nest density on chicks' growth rate and survival. On Appledore Island, Maine, Herring Gulls nest both in dense subcolonies and in more isolated situations, affording a unique opportunity for comparison of reproductive success of pairs nesting in both contexts on the same island. Chicks reared in dense subcolonies grew at a rate significantly higher than that of those reared in more isolated settings. Using mark-recapture analysis, we found that a chick's expected survival is dependent on hatch weight, hatch date, hatch order, and context (nest in dense or loose subcolony). The first chick to hatch in each nest had a significantly greater probability of surviving to fledging than the last-hatched chick. Last-hatched chicks had a significantly greater chance of survival from hatching to fle...

Single nucleotide polymorphism in the STAT5b gene is associated with body weight and reproductive traits of the Jinghai Yellow chicken

In our research, signal transducer and activator of transcription 5b (STAT5b) gene was studied as candidate gene associated with body weight and reproductive traits of Jinghai Yellow chicken. Single nucleotide polymorphisms (SNPs) of STAT5b gene were examined in both Jinghai Yellow chicken and three reference chicken populations including the Bian, Youxi and Arbor Acre chickens. Two SNPs (C-1591T and G-250A) were detected in the 5' flanking region of STAT5b gene. Association indicated that the C-1591T mutation is significantly associated with age at fist egg, The G-250A mutation is significantly related with hatch weight and body weight at 300days. Additionally four STAT5b haplotypes (H1, CG; H2, TG; H3, AC and H4, TA) and their frequency distributions were estimated using the phase program. Diplotype H3H4 is dominant for 8, 16week-age-weight and body weight at first egg. Thus STAT5b gene may be served as a potential genetic marker for growth and reproduction traits evaluation of the Jinghai Yellow chicken. This study will provide valuable information for the protection and breeding of Jinghai Yellow chicken.

Evaluation of Reproductive Performance and Egg quality Traits in Progenies of Dominant Black Strain Crossed with Fulani Ecotype Chicken

This study was undertaken to contribute to the genetic improvement of the indigenous chicken by direct andreciprocal crossing with an exotic egg type strain Dominant Black (DB). Results indicated significant (P<0.05)effect of genotype on fertility and hatchability of eggs. Percentage fertility across the genotypes was, 73.00,76.24, 59.88 and 54.12%, while hatchability was 73.90, 78.30, 70.45 and 70.10%, for DBxDB, DBxFE, FExDBand FExFE, respectively. There was no significant (P>0.05) difference in hatch weight of the chicks. The crossbred (DBxFE and FExDB) had higher egg weight (51.45g and 51.35g vs. 47.19), total egg number for 100 days(51 and 53 vs. 40) and hen day production (50.87 and 52.47 vs. 46.05) than the pure bred Fulani Ecotype.FExDB had significantly higher body weight at first egg (1408g) than DBxFE (1388g). Mortality wassignificantly (P<0.05) higher in DBxDB than other genotypes during the laying period. Significant and nonsignificant differences existed in internal and external egg quality traits across the genotypes.

Effect of match or mismatch of maternal–offspring nutritional environment on the development of offspring in broiler chickens

In mammals, maternal food restriction around conception and during pregnancy results in low birth weight and an adjusted growth trajectory of offspring. If, subsequently, the offspring are born into a food-abundant environment, they are at increased risk of developing obesity, type 2 diabetes, hypertension and renal dysfunction. Here, we show similar effects of maternal undernutrition on hatch weight, growth and fat deposition in offspring of birds (domestic chicken). Both mothers and offspring were fed either ad libitum or restricted in a two-by-two factorial design, resulting in two matched and two mismatched maternal–offspring nutritional environments. Offspring of ad libitum mothers grew heavier than those of restricted mothers, possibly due to the larger muscle mass. Ad libitum-fed offspring, especially females, of restricted mothers were lighter at hatch, and were heavier and had more abdominal fat at 6 weeks of age than daughters of ad libitum-fed mothers. These results suggest a common mechanism in mammals and birds in response to a mismatch in the maternal–offspring nutritional environment. They also indicate that the common practice of restrictive feeding of the broiler breeders and subsequent ad libitum feeding of the broilers may result in reduced growth and increased abdominal fat as compared to broilers of less restricted broiler breeders.

Improved hatchability and posthatch performance in turkey poults receiving a dextrin-iodinated casein solution in ovo

Two experiments were conducted with a commercial turkey company using a commercial egg injection system to investigate the effect of a dextrin-iodinated casein solution injected in ovo at 25 d of incubation on turkey poult hatchability, hatch weight, and growth (6 or 7 d posthatch). In experiment 1, a total of 3,900 turkey eggs (1,300 per group) were injected at 25 d of incubation with either 200 μL of a control (physiological saline) solution or a dextrin solution (18% maltodextrin and 10% potato starch dextrin) with 75 or 375 μg/mL of iodinated casein (DexIC75 or DexIC375, where Dex and IC refer to dextrin and iodinated casein, respectively). Two hundred poults from each group were neck-tagged, weighed (hatch weight), placed in a commercial turkey house within a single brooder ring, and weighed again (7 d posthatch). In experiment 2, a total of 5,200 eggs (2,600 per group) were injected with the control or DexIC75 solution. A total of 600 poults (300 per group) were neck-tagged and hatch weights were obtained, followed by placement in a single brooder ring in a commercial house and a second weighing (6 d posthatch). Eggs in experiments 1 and 2 were obtained from hen flocks that were 33 and 5 wk into the laying cycle, respectively. In experiment 1, the DexIC75 injection resulted in a 1.8% increase (P = 0.03) in hatch weight. In experiment 2, the DexIC75 treatment resulted in a 2.4% increase in hatchability (P = 0.01), a 4.3% increase in hatch weight (P < 0.001), and a 1.8% increase in 6-d poult weights (P < 0.03) compared with controls. Results of this study indicate that a solution containing dextrin and 75 μg/mL of iodinated casein injected into turkey eggs at 25 d of incubation may be used to improve early poult weights, hatchability, or both in commercial turkey production.

Effects of the thyroid hormone responsive spot 14α gene on chicken growth and fat traits

The thyroid hormone responsive spot 14alpha (THRSPalpha) gene plays important roles in chicken growth and fat deposition. The aim of this study was to identify new variations in the gene to determine their effects on growth and fat traits in chicken and to observe the effects of the THRSPalpha gene on chicken lipid profile and lipoprotein and glucose and triiodothyronine effects on the THRSPalpha expression in liver and fat cells. Two new variations, namely A197835978G and G197836086A, and a reported 9-bp insertion-deletion (indel) of the THRSPalpha gene were genotyped by single-stranded conformational polymorphism in a Xinghua x White Recessive Rock F(2) full-sib resource population. The results showed that the A197835978G was significantly associated with hatch weight and BW at 28 d of age and breast muscle weight at 90 d of age in chickens (P < 0.05). The G197836086A was significantly associated with cingular fat width (P = 0.0349) and breast muscle crude fat content (P = 0.0349). The indel was significantly associated with abdominal fat weight (P = 0.0445). The above new THRSPalpha polymorphisms were also significantly associated with the total cholesterol and low-density lipoprotein, in which the THRSPalpha GA/AG genotype was associated with lipid and lipoprotein and the THRSPalpha BB indel genotype was significantly associated with liver weight in chicken breeds. The mRNA expression analysis in vivo and in vitro culture studies suggested that the THRSPalpha gene is more responsive to glucose than triiodothyronine. In conclusion, the 3 variations of the chicken THRSPalpha gene were associated with both growth and fat traits in this study. Such effects of the THRSPalpha gene were further supported from the data of observations in association analysis of the gene with phenotypic records and plasma lipid profiles, in the THRSPalpha gene expression in chicken development, and in vivo and in vitro cell culture observation of liver and abdominal fat tissues.

Genetic and phenotypic parameter estimates for body weights and egg production in Horro chicken of Ethiopia

A breeding program has been established in 2008 to improve productivity of Horro chicken, an indigenous population in the western highlands of Ethiopia. The pedigree descended from 26 sires and 260 dams. Body weights were measured every 2 weeks from hatch to 8 weeks then every 4 weeks for the next 8 weeks. Egg production was recorded to 44 weeks of age for one generation. Genetic parameters were estimated using animal model fitted with common environmental effects for growth traits and ignoring common environment for egg production traits. Direct heritabilities ranged from low (0.15 ± 0.08), for body weight at 6 weeks, to moderate (0.40 ± 0.23), for hatch weight. Heritabilities of common environmental effects on growth were high at hatch (0.39 ± 0.10) and remained low afterwards. Age at first egg showed a very low heritability (0.06 ± 0.15). Heritabilities of egg numbers in the first, second, third, and fourth months of laying were 0.32 (±0.13), 0.20 (±0.16), 0.56 (±0.15), and 0.25 (±0.14), respectively. Heritabilities of cumulative of monthly records of egg numbers were from 0.24 ± 0.16 (for the first 2 months, EP12) to 0.35 ± 0.16 (over the 6 months, EP16). Body weight at 16 weeks of age (BW16) has a strong genetic correlation with the cumulative of monthly records: 0.92 (with EP12), 0.69 (with EP36), and 0.73 (with EP16). Besides their strong association, BW16 and EP16 showed higher heritability, relative to their respective trait categories. These two traits seemed to have common genes and utilizing them as selection traits would be expected to improve both egg production and growth performance of local chicken. However, the standard errors of estimates in this study were mostly high indicating that the estimates have low precision. Parameter estimations based on more data are needed before applying the current results in breeding programs.

Clock Genes Localize to Quantitative Trait Loci for Stage-Specific Growth in Juvenile Coho Salmon, Oncorhynchus kisutch

In most organisms, an internal circadian clock coordinates the expression of biological rhythms and enables individuals to anticipate and respond to the seasonally changing environment. There is remarkable conservation of function in the molecular machinery underlying this circadian clock across taxa with 4 canonical proteins interacting to form an autoregulatory feedback loop: CLOCK, CRYPTOCHROME, PERIOD, and BMAL. We mapped duplicated copies of Clock and Cryptochrome in coho salmon (Oncorhynchus kisutch) to determine if these genes localize to quantitative trait loci (QTL) for hatch timing, weight, length, and growth rate measured throughout the juvenile life-history stage. We found that Cryptochrome2b mapped to a QTL region for growth (measured at 304 days post-hatching) on linkage group OKI06. The percentage of variation (PEV) explained by this QTL was 15.2%. Cryptochrome2b was also associated with a marginally nonsignificant QTL for length (measured at 395 days post-hatching). OtsClock1b mapped to a QTL region for growth rate (PEV 10.1%) and length (PEV 10.5%) on linkage group OKI24 (measured at 479 days posthatching). Neither gene localized to QTL for hatch timing or weight. Our findings indicate that the growth rate and length QTL associated with OtsClock1b and Cryptochrome2b are development stage-specific and may result from temporally differentiated gene expression patterns.

Relationship Between Egg Weight and Hatch Weight in Pigeons (Columba livia)

2 Abstract: This study was undertaken to assess the relationship between egg weight and hatch weight in pigeons and also derive prediction equation based on the relationship. It was conduced in nine randomly selected households in Misau town of Bauchi State, Nigeria, between April and November 2009. The mean egg weight and squab hatch weight were 14.46±0.11 g and 12.55±0.08 g, respectively. No significant differences were detected in egg weight and squab hatch weight when compared on the basis of order of lay. The two traits were strongly correlated (r = 0.932). The study has shown that body weight of squabs at hatching is to a large extent determined by the weight of the egg (R = 86.9%) and can be predicted using the 2

Chronic prenatal lead exposure impairs long-term memory in day old chicks

Environmental exposure to lead during developmental stages has been established as a potential cause of intellectual deficits. The high susceptibility of rapidly developing fetal and infant brains to external factors suggests that impairment of later cognitive functions may arise from relatively minor prenatal exposure to environmental lead levels. In this study, we used the one-trial passive avoidance learning paradigm with day old chicks to evaluate memory function and memory consolidation in response to prenatal lead exposure. Lead acetate (5.5mg/kg, 11mg/kg, 16.5mg/kg) was administered daily from E9 to E16 via direct injection into the airspace in chick eggs. Higher doses of lead acetate (11mg/kg, 16.5mg/kg) administration had significant effects on the hatching success (23.4 and 17, respectively) and hatch weight ( approximately 10% decrease) of chicks when compared to equivalent treatments of sodium acetate (11mg/kg, 16.5mg/kg) (p<0.001). Low doses of lead acetate (5.5mg/kg) did not significantly affect chick hatching, weight or morphology compared to equivalent sodium acetate treatments (5.5mg/kg) and controls. However, lead acetate (5.5mg/kg) was found to significantly impair long-term memory after 120min following training in the one-trial passive avoidance learning task (p<0.05). These findings add to a growing body of evidence that suggests lead toxicity during fetal development leads to impairment in cognitive and memory processes.

Effect of egg composition on hatchability and on growth and slaughter characteristics of meat-type chicks

1. Using the so-called TOBEC (Total Body Electrical Conductivity) method, which allows the determination of egg composition in vivo, correlations between egg composition, hatchability and hatched chicks’ development were studied. 2. A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation. 3. During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity. 4. It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight. 5. It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity. 6. At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity. 7. Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter. 8. Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case. 9. Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition. 10. This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development.

Quantitative trait locus analysis of hatch timing, weight, length and growth rate in coho salmon, Oncorhynchus kisutch

In quantitative genetics, multivariate statistical approaches are increasingly used to describe genetic correlations in natural populations, yet the exact genetic relationship between phenotype and genotype is often unknown. Quantitative trait locus (QTL) analyses can be used to describe the molecular basis of this relationship. In salmonids, growth and development are important fitness traits that are phenotypically correlated with each other and with other life-history traits, and an understanding of the molecular basis of these relationships is valuable for future evolutionary studies. Here, a QTL analysis using an outbred cross was initiated to determine the molecular basis of phenotypic correlations between such growth traits in coho salmon (Oncorhynchus kisutch), an important fish species distributed throughout the North Pacific Ocean. Fifty-three QTL for growth rate, length and weight at eight time periods were located on seven linkage groups (OKI03, OKI06, OKI18, OKI19, OKI23, OKI24 and an unnamed linkage group) or associated with five unlinked markers (Omm1159, Omm1367/i, Omy325UoG, OmyRGT55TUF and OtsG422UCD). One QTL for hatch timing was associated with the marker, Omm1241. All QTL were of minor effect, explaining no more than 20% of the observed variation in phenotypic value. Several instances of colocalization of QTL weight, length and growth rate were observed, suggesting a genetic basis for phenotypic correlations observed between these traits. This study lays the foundation for future QTL mapping efforts, for detailed examinations of the genetic basis of phenotypic correlations between growth traits, and for exploring the adaptive significance of growth traits in natural populations.

Influence of in ovo inoculation with various nutrients and egg size on broiler performance

This study evaluated the influence of inoculation of different nutrients into eggs of 18-d-old broiler embryos. On d 18 of incubation, before transferring, eggs were injected with a solution containing either maltose, a multivitamin supplement, zinc-glycine, glutamine, a mixture containing all these elements, or sodium chloride (control). After hatching, 2,400 male broiler chicks were placed in an experimental broiler house and distributed into 60 floor pens in a completely randomized design comprising a 2 × 6 factorial arrangement of treatments (2 egg weights × 6 solutions), for a total of 12 treatments. Birds and feed consumption were measured weekly. At 42 d of age, 3 birds per replicate pen were randomly selected for processing. Birds derived from heavier eggs had greater hatchability and hatching weight. At 42 d of age, birds from heavier eggs had higher BW, carcass weight, and breast meat weight. The livability of birds derived from heavy eggs was higher at 7 and 14 d of age. The in ovo inoculation of the nutrients to 18-d-old embryos did not influence live performance or carcass traits. The technique of in ovo inoculation of certain nutrients may be used in industrial poultry production, but further studies are required to define the best solutions or mixture of nutrients to be used.

Effect of egg size on chick hatch weight and subsequent body weights of two strains of Rhode Island chicks under selection

An experiment was conducted to investigate the effect of egg size on chick hatch weight and the subsequent weights of chicks up to 12 weeks of age in Rhode Island Red and White strains of Chickens. The mean egg size were 50, 54.4 and 59.6 g for small, medium and large eggs, respectively for the red strain, and were 51.7, 57.5 and 63.7g, respectively, for the white strain. The weight of the chicks as a percentage of egg weight was not significantly influenced by the group they were hatched from. However body weight up to 12 to 12 weeks of age differed significantly when eggs were classified into small, medium and large size. Though the body weight of chicks from medium and large size eggs were not significantly (P&gt;0.05) different after the first week of life in either strain. Key words: Egg size, Growth, Hatch weight, Body weight, Layers &nbsp

Egg traits, fertility, hatchability and chick survivability of Rhode Island Red, local and crossbred chickens

SUMMARY The local chicken has profound potential for upgrading through cross breeding with improved commercial birds to increase meat and egg production. This study aimed at evaluating egg traits, hatchability, fertility, chick hatch weight, and chick survivability of commercial Rhode Island Red (RIR), local, and crossbred chickens. A total of 6752 local chicken eggs were collected to obtain breeding stock and to study egg traits. RIR breeding stock was obtained from raising 250 (50 males, 200 females) while crossbred chickens were obtained by crossing RIR layer cocks to local hens and vice versa. A total of 1382, 1523, and 1476 local, RIR, and crossbred chicken eggs respectively were assessed for egg weight, length, breadth, and volume as well as chick hatch weight. Fertility and hatchability were assessed in 3675 local chicken eggs and 3350 eggs from RIR and crossbred chicken each. There was no significant difference (p < 0.05) in egg traits and chick hatch weight between RIR and crossbred chickens but these birds had significantly higher egg weight, egg length, egg breadth, egg volume, and chick hatch weight than local chickens. There were significant (p < 0.0001) positive relationships between egg volume and egg weight, chick hatch weight and egg weight, and chick hatch weight and egg volume for all chickens. Fertility was 92.0±4.14, 91.1±4.42, and 94.5±2.21 for local, RIR, and crossbred chickens respectively. Hatchability varied significantly at p<0.05 (80.6±1.43 in crossbred, 64.0±2.16 in RIR, and 52.2±2.54 in local chickens). Survivability of local chicks was superior by 50% over RIR and crossbred chicks. It is concluded that cross breeding local chickens to RIR produces a superior breed to local ecotype in terms of egg traits, hatchability and survivability. Such superiority can be exploited to upgrade the genetic potential of local ecotype and thus improve poultry production.

Effect of Dietary Curcuma, Capsicum, and Lentinus, on Enhancing Local Immunity against Eimeria acervulina Infection

The protective effect of orally administered Curcuma longa (turmeric), Capsicum annuum and C. frutescens (hot pepper), and Lentinus edodes (shiitake mushroom) on avian coccidiosis was evaluated in young broilers. Broiler chickens were continuously fed with a standard diet or standard diet supplemented with Curcuma, Capsicum/Lentinus or Curcuma/Capsicum/Lentinus from hatch and body weight gains, fecal oocyst shedding, antibody titers, and pro-inflammatory cytokine gene expression were measured as parameters of protective immunity following challenge infection with E. acervulina. Chickens fed the Curcuma/Capsicum/Lentinus-supplemented diet showed significantly improved body weight gains compared with birds on the standard diet or birds given Capsicum/Lentinus-supplemented diet following challenge infection with E. acervulina. Chickens fed the Curcuma/Capsicum/Lentinus-supplemented diet shed significantly reduced fecal oocysts and produced higher serum antibody titers compared with the groups fed the standard diet or fed Curcuma or Capsicum/Lentinus. Finally, the levels of local cytokine transcripts of IL-1β, IL-6, IL-15, and IFN-γ were consistently greater in the Curcuma/Capsicum/Lentinus-fed group compared to the controls fed only the standard diet, Curcuma, or Capsicum/Lentinus groups. This study provides first immunological evidence that dietary supplementation of turmeric, hot pepper, and shiitake mixture significantly enhances local innate immunity and provides higher protective immunity against E. acervulina infection.

A polyandrous female moth discriminates against previous mates to gain genetic diversity

Polyandry is common in many animal species. The hypotheses proposed to explain the evolution of polyandry generally fall into two categories: to gain material benefits and to obtain genetic benefits. Here we report our findings on a polyandrous moth, Ephestia kuehniella (Lepidoptera: Pyralidae). The present study does not support the hypothesis that females gain material benefits from multiple copulations in terms of sperm replenishment, fecundity and longevity, because females that copulated once and females that copulated more than once with the same or different males had similar fertility, fecundity and longevity. Females used three strategies to gain possible genetic benefits: discriminating against previous mates probably via chemical cues, giving 60% chance of paternity to second males, and adjusting their oviposition patterns depending on whether they encountered new or previous mates after the first copulation. For the third strategy, females that encountered new mates after the first copulation saved eggs until the next day to facilitate fertilization of their eggs with the sperm of their new mates. Our findings do not support the hypothesis that polyandry increases offspring viability, because polyandry did not affect egg hatching success, offspring survival or weight. Ephestia kuehniella showed limited ability to disperse, and females laid all their eggs locally, mostly within 2 days, suggesting that offspring live together and that sib copulations are common in this species. Therefore, polyandry is probably a mechanism for reducing sib competition and inbreeding costs in offspring.

Associations of GHSR gene polymorphisms with chicken growth and carcass traits

Ghrelin receptor (GHSR), or growth hormone secretagogue receptor, modulates many physiological effects by binding to its ligand and therefore is a candidate gene for chicken production performance. In this study, five polymorphisms (four SNP and a 'GGTACA' indel) of GHSR gene were genotyped in a F(2) full sib chicken population to investigate their associations with production traits. Results showed that c.739 + 726T > C (M2) was significantly associated with body weight (BW) at 28 days (BW28), BW90, dressed weight, eviscerated weight, eviscerated weight with giblet, breast muscle weight and leg muscle weight (P < 0.05). Meanwhile, T allele rather than C was positive for chicken body weight gain as individuals with CC had the lowest value of all traits. Otherwise, no significant association of c.264G > A (M1), c.3211-196_3211-181delGGTACA (M3), c.3211 + 75C > T (M4), and c.3211 + 150C > T (M5) with any growth and carcass traits was found. Haplotypes based on five polymorphisms were significantly associated with hatch weight, BW7, BW14, BW21 and breast angle (P < 0.05), as well as BW28 (P < 0.01). Therefore, it was concluded that M2 of the GHSR gene and the analyzed haplotypes were associated with some chicken growth and carcass traits.

Effects of Housing Systems on Growth Performance, Blood Plasma Constituents and Meat Fatty Acids in Broiler Chickens

A research was conducted to determine the influence of the conventional and the free-range broiler housing systems using female broiler chicks had low hatching weight on growth performance, breast meat characteristics and some blood plasma parameters. In the conventional (totally confined) housing system sixty one-day-old female Ross broiler chicks were placed in indoor floor pens with three replicates of 20 chicks. In the free-range (partly-confined) housing system, sixty one-day-old Ross broiler chicks were placed in indoor floor pens and also accessed to a grass paddock during 44 day experimental period after 7 days old. Birds of both systems were fed the same commercial broiler diet. The free-range housing system significantly decreased the total feed intake and body weight of broilers (p<0.05). The redness (a* color) and yellowness (b* color) in breast meat were affected by the housing systems (p<0.05). The housing systems had no affect on fatty acids composition of breast meat (p>0.05). The plasma triglyceride and VLDL levels of the conventional reared birds were significantly higher than those reared the free-range (p<0.05). In conclusion, longer growth period was necessary to the free-range reared broilers.