Commercial Chicken Strains Research Articles

Welfare-Related Behaviors in Chickens: Characterization of Fear and Exploration in Local and Commercial Chicken Strains.

Simple SummaryLocally adapted chicken strains are frequently discussed as a favorable alternative in poultry production. They might serve as dual-purpose and robust strains that have advantageous behaviors, such as exploration and reduced fear reactions, which might support animal welfare in general. Therefore, it is important to characterize welfare-related behaviors, such as fear and exploration, and to identify these behavioral traits among the diversity of chicken strains. The aim of this study was to characterize fear reactions and exploration based on the avoidance of a novel object and the avoidance of a human in three different chicken strains. To identify interesting alternatives for future poultry production, a layer hybrid (Lohmann Brown), a dual-purpose hybrid (Lohmann Dual) and a locally adapted strain (Rhinelander) were tested for their fear and exploration behavior towards unknown objects and humans. Results showed clear differences in fear and exploration between all three strains, regarding fear of objects and humans. The strain-specific results illustrate the high diversity of behavioral traits. The understanding of behavioral diversity, including fear and exploration, might contribute substantially to future breeding programs, including of commercial strains, and the preservation of local strains in general, which can improve animal welfare on a genetic and individual basis.Fear and exploration are crucial traits determining how animals behave in novel situations, and thus, they influence animal welfare. The aim of this study was the characterization of these behavioral traits among different strains to identify interesting alternatives for future poultry production. Whereas the Novel Object Test (NOT) focuses on fear and exploration of novel objects, the Avoidance Distance Test (ADT) addresses this in the context of humans. Here, a commercial hybrid line, a dual-purpose hybrid and a local adapted strain were tested. For the differences between strains and development of fear, Lohmann Brown (n = 714), Lohmann Dual (n = 844) and Rhinelander (n = 458) were observed weekly until maturity. Results show that fear and exploration towards unknown objects and humans are breed-specific (all p < 0.01). Additionally, development of fear in NOT and ADT differed between all three strains (both p < 0.01). The expressions of fear of humans or objects should be regarded as characteristics adapted for different husbandry systems and breeding goals, e.g., high exploratory behavior in aviary or high avoidance of predators in free-ranging husbandry or at least a balanced ratio between fear and exploration. Characterization of behavioral traits among different strains, understanding diversity and integrating these behaviors into future breeding and husbandry systems might reflect the need to preserve local strains and the potential to improve animal welfare.

Emerging Genetic Tools to Investigate Molecular Pathways Related to Heat Stress in Chickens: A Review.

Simple SummaryNew genomic tools have been used as an instrument in order to assess the molecular pathway involved in heat stress resistance. Local chicken breeds have a better attitude to face heat stress. This review aims to summarize studies linked to chickens, heat stress, and heat shock protein.Chicken products are the most consumed animal-sourced foods at a global level across greatly diverse cultures, traditions, and religions. The consumption of chicken meat has increased rapidly in the past few decades and chicken meat is the main animal protein source in developing countries. Heat stress is one of the environmental factors which decreases the productive performance of poultry and meat quality. Heat stress produces the over-expression of heat shock factors and heat shock proteins in chicken tissues. Heat shock proteins regulate several molecular pathways in cells in response to stress conditions, changing the homeostasis of cells and tissues. These changes can affect the physiology of the tissue and hence the production ability of chickens. Indeed, commercial chicken strains can reach a high production level, but their body metabolism, being comparatively accelerated, has poor thermoregulation. In contrast, native backyard chickens are more adapted to the environments in which they live, with a robustness that allows them to survive and reproduce constantly. In the past few years, new molecular tools have been developed, such as RNA-Seq, Single Nucleotide Polymorphisms (SNPs), and bioinformatics approaches such as Genome-Wide Association Study (GWAS). Based on these genetic tools, many studies have detected the main pathways involved in cellular response mechanisms. In this context, it is necessary to clarify all the genetic and molecular mechanisms involved in heat stress response. Hence, this paper aims to review the ability of the new generation of genetic tools to clarify the molecular pathways associated with heat stress in chickens, offering new perspectives for the use of these findings in the animal breeding field.

Comparative Amino Acid Ileal Digestibility of Feed Ingredients Measured with Indigenous and Commercial Strains of Chickens

Comparative Amino Acid Ileal Digestibility of Feed Ingredients Measured with Indigenous and Commercial Strains of Chickens

Diversity of Intestinal Bacterial Microbiota of Indigenous and Commercial Strains of Chickens Using 16S rDNA-Based Analysis.

Simple SummaryLittle is known about how the bacterial community differs among different genetic breeds of chickens, especially those with various growth rates, such as in local native chickens. Our data, generated by molecular detection revealed the heterogeneity of bacterial populations existing in different intestinal segments for the two strain of chickens.The objective of this study was to assess the relative abundance of bacteria microflora in different segments of the gastrointestinal tract (duodenum, jejunum, ilium, and cecum) of indigenous (local Omani) and commercial (Cobb 500) chicken strains. Birds were raised under an intensive management system fed a nonmedicated corn-soybean meal diet from Day 0–35 days of age. Using 16S rDNA-based analysis the study showed that in both breeds of birds Bacilli were the most abundant class of bacteria in the duodenum, jejunum, and ileum. Local Omani chickens had significantly higher numbers of Clostridia at most time periods. Actinobacteria were found in higher numbers and reached 54.9% of the bacteria in the jejunum at Day 35 in Cobb 500 versus only 5.42% in the Omani chickens. The bacterial microbiota relative abundance differed significantly (p < 0.05) across different intestinal segments of the two strains, suggesting that each region developed its own bacterial community and the relative abundances of these were quite different.

Comparative Evaluation of Growth Performance, Meat Quality and Intestinal Development of Indigenous and Commercial Chicken Strains

Comparative Evaluation of Growth Performance, Meat Quality and Intestinal Development of Indigenous and Commercial Chicken Strains

Transfer of arsenic from poultry feed to poultry litter: A mass balance study

Roxarsone (rox), an arsenic (As) containing organic compound, is a common feed additive used in poultry production. To determine if As present in rox is excreted into the poultry litter without any retention in chicken meat for safe human consumption, the transference of As from the feed to poultry excreta was assessed using two commercial chicken strains fed with and without dietary rox. The results revealed that both the strains had similar behaviour in growth (chicken weight; 2.17–2.25kg), feed consumption (282–300kgpen−1 initially containing 102 chicken) and poultry litter production (73–81kgpen−1) during the growth phase of 35days. Our mass balance calculations showed that chickens ingested 2669–2730mg As with the feed and excreted out 2362–2896mg As in poultry litter during the growth period of 28days when As containing feed was used, yielding As recovery between 86 and 108%. Though our complementary studies show that residual arsenic species in rox-fed chicken meat may have relevance to human exposure, insignificant retention of total As in the chicken meat substantiates our mass balance results. The results are important in evaluating the fate of feed additive used in poultry production and its potential environmental implications if As containing poultry litter is applied to soil for crop production.

Comparative Study on Growth Patterns of 25 Commercial Strains of Korean Native Chicken

Prediction of growth patterns of commercial chicken strains is important. It can provide visual assessment of growth as function of time and prediction body weight (BW) at a specific age. The aim of current study is to compare the three nonlinear functions (i.e., Logistic, Gompertz, and von Betalanffy) for modeling the growth of twenty five commercial Korean native chicken (KNC) strains reared under a battery cage system until 32 weeks of age and to evaluate the three models with regard to their ability to describe the relationship between BW and age. A clear difference in growth pattern among 25 strains were observed and classified in to the groups according to their growth patterns. The highest and lowest estimated values for asymptotic body weight (C) for 3H and 5W were given by von Bertalanffy and Logistic model 4629.7 g for 2197.8 g respectively. The highest estimated parameter for maturating rate (b) was given by Logistic model 0.249 corresponds to the 2F and lowest in von Bertalanffy model 0.094 for 4Y. According to the coefficient of determination (<TEX>$R^2$</TEX>) and mean square of error (MSE), Gompertz and von Bertalanffy models were suitable to describe the growth of Korean native chicken. Moreover, von Bertalannfy model was well described the most of KNC growth with biologically meaningful parameter compared to Gompertz model.

한국 재래닭의 부화 후 성장단계별 넙다리뼈와 정강뼈 성장에 관한 연구

Skeletal development of chicken has been widely discussed in industrial forums and various research reports. However, these studies were emphasis on the commercial chicken strains for improve egg and meat production whereas the skeletal quiet remains as a potential weak link related to facilitating in the physical support of heavier carcasses at ever younger ages. For that, the study of standardization of skeletal development is important but it was rarely reported in Korean native chicken (KNC). The study was investigated the skeletal characteristics of KNC for international standardization. We studied in KNC at 2, 14, 28, 42, 56, 70, 84, 98, 112, 126, 147, 168, 196, 224, 336 and 448 days after hatch (male and female, n=13 for each group). We measured the body weight (BW), and after sacrifice measured organs and remove muscle from femur & tibia and measured bone weight. Data were analyzed by ANOVA, Duncan test, correlation analysis and regression analysis of SAS 9.1. We analyzed the data of BW, femur & tibia and made growth curve also. The BW was significantly increased up to 147 days after hatch (male, <TEX>$1,927.88{\pm}68.92g$</TEX>; female, <TEX>$1,456.00{\pm}50.11g$</TEX>), and then increased gradually. At 336 days, these growth was stop (male, <TEX>$2,467.00{\pm}42.84g$</TEX>; female, <TEX>$1,568.71{\pm}62.62g$</TEX>). The growth of femur & tibia length and width was stop on 98~126 days after hatch. At 98 days, we measured the length and width of femur & tibia in male were <TEX>$132.39{\pm}3.18mm$</TEX> & <TEX>$25.98{\pm}0.59mm$</TEX> whereas in female at 112 days the length of femur & tibia was <TEX>$116.40{\pm}1.55mm$</TEX> and at 126 days width was <TEX>$21.41{\pm}0.38mm$</TEX>. Our study suggests that the growth of male KNC was classified pre-puberty (0~98 days), puberty (98~336 days) and maturity (after 336 days), meanwhile female was shown similar trend however puberty period of KNC was 112 or 126 days after hatch.

Characterization of muscle fiber type in the pectoralis major muscle of slow-growing local and commercial chicken strains

The study aimed to characterize muscle fiber type of the pectoralis major muscle of slow-growing chickens belonging to the Padovana local breed, the commercial strain Berlanda gaina, and their cross. Forty-five chickens (both males and females) from the different genotypes were grown up to 180 d. Histochemical and morphometrical analyses were performed to characterize muscle fiber types, myofiber density, and myofiber size of the different genotypes. The effects of genotype, sex, and their interaction were estimated. Muscle samples appeared almost entirely made up of IIB fiber type, whereas a low percentage of area (5 to 6%) was composed of hypercontracted fiber. Myofiber density was significantly higher (P < 0.05) in Padovana strains and cross-sectional area was significantly lower (P < 0.01) than in Berlanda strain. Muscle fiber characteristics appeared not to be affected by the interaction of genotype × sex.

Progression of Histomonosis in Commercial Chickens Following Experimental Infection with anIn VitroPropagated Clonal Culture ofHistomonas meleagridis

Four commercial strains of chickens, namely, ISA brown leghorn (ISA), TETRA-SL brown (TETRA-SL), Lohmann brown (LB), and Lohmann LSL (LSL), were infected with a well-defined clonal culture of Histomonas meleagridis (H. meleagridis/Turkey/Austria/2922-C6/04) to investigate their susceptibility to histomonosis. Each group included 16 chickens, which were housed under the same conditions in separate pens. All chickens were infected with 10(4) histomonads orally and intracloacally at 14 days of age. No mortality or clinical signs were observed during the experiment in all birds. Three birds of each chicken strain were euthanatized on days 4, 7, 10, 14, and 21 postinfection. Incidence of histomonosis on the basis of cecal lesions was found to be 64.00% in TETRA-SL, 62.50% in LB, 53.12% in LSL, and 43.75% in ISA chickens. Fewer lesions were noticed in livers than in ceca, with an incidence of 15.62% in TETRA-SL, 9.37% in LB, and 3.12% in ISA chickens. No liver lesions were found in the LSL chickens. Statistical analysis revealed that there was no significant difference (P > 0.05) in susceptibility to experimental H. meleagridis infection based on cecal and liver involvement. Polymerase chain reaction (PCR) and immunohistochemistry were found to be reliable tools to confirm the presence of histomonads and changes in the ceca. However, some negative PCR results were recorded from the livers despite the presence of macroscopic lesions. Additionally, DNA of H. meleagridis was detected by PCR in a few of the lungs, but immunohistochemistry was negative. Nucleic acid of the protozoan parasite was not detected in samples from kidney, brain, spleen, or bursa of Fabricius. Altogether, the high susceptibility of commercial chicken lines to histomonosis could be demonstrated and characterized by severe lesions in the ceca and insignificant involvement of the liver, approaching a maximum on days 7-14 postinfection.

Study on the genetic diversity of native chickens in northwest Ethiopia using microsatellite markers.

In this study, indigenous chicken populations representing seven different areas of northwest Ethiopia were studied using microsatellite markers to determine genetic diversity and variation. Three local lines of South African chicken and two commercial chicken strains were included for comparison. The Ethiopian chicken population Gassay/Farta had the highest number of alleles per locus (10) for microsatellite marker MCW 158. MCW 154 was the most polymorphic marker across all populations with an average of seven different alleles. A high genetic diversity was observed in overall loci for all populations with heterozygosity (Ho) value of 0.77. The highest heterozygosity (0.93) across all markers was observed in the Mecha chicken population, while the lowest heterozygosity across all loci (0.66) was observed in the White Leghorn breed. The RIR commercial chicken breed showed higher genetic distance (lower genetic similarity) with the Ethiopian chicken populations than the South African fowls. This indicates that the Ethiopian indigenous chicken populations are still not highly diluted by the RIR chicken breed either through the extension program or through the regional poultry breeding and multiplication institutes. Based on the phylogenetic tree result, it is concluded that the clustering of the chicken populations in the present study are in accordance with the origin and marketing systems of these native chickens, which indicates that the microsatellite markers used in this study were suitable for the measurement of the genetic biodiversity and relationship of Ethiopian chicken populations. These results can therefore serve as an initial step to plan the characterization and conservation of native chickens in Amhara region, Ethiopia.

Sequence and phylogenetic analysis of chicken anaemia virus obtained from backyard and commercial chickens in Nigeria : research communication

This work reports the first molecular analysis study of chicken anaemia virus (CAV) in backyard chickens in Africa using molecular cloning and sequence analysis to characterize CAV strains obtained from commercial chickens and Nigerian backyard chickens. Partial VP1 gene sequences were determined for three CAVs from commercial chickens and for six CAV variants present in samples from a backyard chicken. Multiple alignment analysis revealed that the 6% and 4% nucleotide diversity obtained respectively for the commercial and backyard chicken strains translated to only 2% amino acid diversity for each breed. Overall, the amino acid composition of Nigerian CAVs was found to be highly conserved. Since the partial VP1 gene sequence of two backyard chicken cloned CAV strains (NGR/CI-8 and NGR/CI-9) were almost identical and evolutionarily closely related to the commercial chicken strains NGR-1, and NGR-4 and NGR-5, respectively, we concluded that CAV infections had crossed the farm boundary.

The melanocortin circuit in obese and lean strains of chicks

Agonists of membranal melanocortin 3 and 4 receptors (MC3/4Rs) are known to take part in the complex control mechanism of energy balance. In this study, we compared the physiological response to an exogenous MC3/4R agonist and the hypothalamic expression of proopic melanocortin (POMC) gene, encoding few MC3/4R ligands, between broiler and layer chicken strains. These strains, representing the two most prominent commercial strains of chickens grown for meat (broilers) and egg production (layers), differ in their food intake, fat accumulation, and reproductive performance and, therefore, form a good model of obese and lean phenotypes, respectively. A single i.v. injection of the synthetic peptide melanotan-II (MT-II; 1 mg/kg body weight) into the wing vein of feed-restricted birds led to attenuation of food intake upon exposure to feeding ad libitum in both broiler and layer chickens. A study of the POMC mRNA encoding the two prominent natural MC3/4R agonists, alpha-MSH and ACTH, also revealed a general similarity between the strains. Under feeding conditions ad libitum, POMC mRNA levels were highly similar in chicks of both strains and this level was significantly reduced upon feed restriction. However, POMC mRNA down-regulation upon feed restriction was more pronounced in layers than in broilers. These results suggest: (i) a role for MC3/4R agonists in the control of appetite; (ii) that the physiological differences between broilers and layers are not related to unresponsiveness of broiler chickens to the satiety signal of MC3/4R ligands. Therefore, these findings suggest that artificial activation of this circuit in broiler chicks could help to accommodate with their agricultural shortcomings of overeating, fattening, and impaired reproduction.

Methods for evaluating and developing commercial chicken strains free of endogenous subgroup E avian leukosis virus

The genome of nearly all chickens contains various DNA proviral insertions of retroviruses of subgroup E avian leukosis virus (ALVE). However, the elimination or control of ALVE gene expression is desirable to improve productivity, to improve resistance to avian leukosis virus (ALV)-induced tumours, and to develop safer live virus vaccines in chick embryos and cultured chick cells. Restriction fragment length polymorphism and polymerase chain reaction methods are used to define the presence of ALVE genes; and the expression of ALVE in chicken plasma or on cells, and the susceptibility of cells to ALVE is determined by flow cytometry using a specific (R2) antibody. ADOL line 0 chickens have been selected to be free of ALVE genes, while being resistant (i.e. lack receptors to ALVE), but susceptible to exogenous ALV (i.e. ALVA, ALVB, ALVC and ALVJ). To develop improved line 0-type chickens, ADOL line 0 was outcrossed to a commercial line that had one ALVE gene and evidence for ALVE resistance. Rous sarcoma virus (RSV) challenge was used to confirm resistance of F1 chickens to ALVE, and susceptibility of F2 breeders to ALVA and ALVB using test chicks produced by matings to line 7(2). Selected F2 breeders were resistant to ALVE, but susceptible to exogenous ALVA, ALVB, ALVC and ALVJ, based on challenge tests of progeny chick cells using an enzyme-linked immunosorbent assay. The new line, 0(1), has evidence for improved egg size, productivity, fertility and hatchability. Similar procedures may be used for development of productive ALVE free chicken lines with preferred ALV susceptibility traits.

Influence of strain of chickens on the immune response to vaccination against Marek's disease

Field trials were conducted to determine the response of different genetic strains of commercial chickens to vaccination against Marek's disease (MD). Cell-associated and cell-free HVT vaccines conferred the same degree of protection within the same strain of chickens. The incidence of MD in vaccinated birds seemed to be correlated with the natural susceptibility of the chicken strains to the disease. Revaccination did not induce better protection in the most susceptible strain.

Effect of Turning and Age of Egg on Hatchability in the Pheasant, Chukar, and Japanese Quail

Eggs from pheasants, Chukar partridge and Japanese quail were stored 1 to 28 days in a cold box where temperature and relative humidity were maintained at approximately 16°C. and 70 percent, respectively. Half the eggs from each species was turned once daily from a 45° angle from the vertical to the opposite angle. Turning eggs prior to incubation had no appreciable effect on hatchability of eggs stored up to 28 days. Length of storage for eggs from the pheasant and quail was critical, with significant declines in fertility in eggs stored beyond 14 days. Storage of Chukar eggs up to 28 days had little effect on subsequent hatchability, and their holding quality was comparable to that for commercial strains of chickens and turkeys.

Analysis of Certain Meat Characteristics of Eight-Week Old Broiler Chickens Representing Two Commercial Lines and Four Mating Types Derived from Them

Three hundred and forty-two 8-week old broiler chickens, representing two commercial strains of chickens and four mating types derived from them, were analyzed for eviscerated weight, cooking losses, Allo-Kramer shear values, color, and total moisture content. Estimates of the parameters studied were obtained on raw and cooked samples of the breast and thigh from each bird. Mean values obtained for the traits studied agreed well with previous reports in the literature. In several instances, however, unduly high coefficients of variation were obtained which suggested that environmental biases of an unknown nature had been encountered.Cooking resulted in a highly significant (P < 0.01) increase in mean shear value of the breast meat as compared to the raw state. Cooking also resulted in a highly significant (P < 0.01) decrease in mean shear value of thigh meat. Cooking resulted in an increase in lighter color (Gardiner L values), also an increase in yellow color (Gardiner B values), and a decrease in red color (Gardiner A values) of breast and thigh meat. Factors contributing to lightening of meat appeared to be acting independently of factors controlling redness and yellowness.Breast moisture averaged lower than thigh moisture in the raw state (72.607 versus 73.697), but breast moisture exceeded that of thigh moisture in the cooked state (67.557 versus 66.457).

Comparison of Hematology between Leghorn-type and Heavy-type Egg Production Stocks

The packed cell volume (P.C.V.) of heavy-type, brown egg commercial strains of chickens carrying a gene, Co, the key Columbian plumage pigmentation restriction gene, was significantly lower than that of Leghorn-type commercial white egg strains. There was no correlation between P.C.V. and body weight within strains and the differences were not influenced by the gene for dominant white (I) or E, e- alleles. The decreased P.C.V. was due primarily to decreased numbers of circulating erythrocytes.

Relationship of Blood Pressure of Hens to Blood Spot Incidence in the Eggs

It is an accepted fact that heredity is an important factor in limiting the incidence of blood spots in eggs of commercial strains of chickens. However, about one percent of all commercially candled eggs are removed from market channels because of blood spots. On a broken-out basis, total blood spot percentages ranged from 2.71 to 5.41 for the commercial strains entered in the 15th Florida Random Sample Test (O’Steen et al., 1968).The differences in blood spot incidence in eggs are theoretically due to differences in (1) capillary fragility, (2) blood clotting time and (3) blood pressure. Bigland et al. (1964) reported that injected chalcones, which reduce capillary fragility, significantly reduced the percentages of blood spots. Siddiqui and Fry (1963), using Warfarin, and Waldroup and Harms (1962) and Day et al. (1964), using dicumarol, found that these anticoagulants in the diets of laying hens increased the clotting or prothrombin time .

Variation Among Commercial Strains of Chickens in Loss of Egg Albumen Quality

ALTHOUGH the level of initial or “fresh” albumen quality is well recognized as having a genetic basis, the genetic determination of rate of albumen quality loss during storage has not been clearly established.Lorenz et al. (1934) claimed that rate of liquefaction of egg white and initial percentage of firm albumen tended to be negatively correlated, while May et al. (1957) obtained a positive correlation of .358 between initial albumen quality and quality loss. The latter also reported highly significant differences among 186 strains in Haugh unit decline after seven days of storage at 55–60°F. However, the validity of their statistical analysis has been questioned (King et al., 1961).Proudfoot (1962) found significant interactions between six strains of Leghorns and storage time but only after interior quality had deteriorated to a low level. He concluded that these interactions were therefore of no importance to the industry.Mueller (1959) noted…