Dual-purpose Chickens Research Articles

Pharmacokinetics of levofloxacin through oral route of administration in dual purpose chicken by the LCMS/MS analytical technique

Pharmacokinetics of levofloxacin through oral route of administration in dual purpose chicken by the LCMS/MS analytical technique

Effect of levofloxacin on liver biochemical parameters following repeated oral administration in dual purpose chicken

Effect of levofloxacin on liver biochemical parameters following repeated oral administration in dual purpose chicken

Seroprevalence, Isolation and Molecular Detection of Infectious Bronchitis in Backyard and Commercial Chickens in Central Gondar Zone, Northern Ethiopia

Infectious bronchitis (IB) is a highly contagious disease of the respiratory and urogenital tract of chickens, caused by infectious bronchitis virus (IBV), a member of the family Coronaviridae. Due to the serious infectious and transmission features of the disease mostly in the reproductive and respiratory systems it causes potential economic loss. Hence a cross-sectional study was conducted from February 2022 to June 2022 on chicken serum and tracheal swab samples from backyard and commercial farms in central Gondar zone, Ethiopia, to determine the seroprevalence of IB, associated risk factors and for isolation and molecular detection of the virus. A total of 384 blood samples were collected and tested by an indirect ELISA and Anti-IBV antibody positivity was noted in 92.19% (95% confidence interval (89 % -94.6 %) of the samples. Logistic regression analysis was performed to determine the impact of possible risk factors on seropositivity. Higher prevalence was noted in young chickens than in adults (p< 0.05) and in exotic breeds than in local breeds (p<0.05). Though the difference was not statistically significant (p>0.05), higher prevalence was obtained in dual purpose chickens (93.75%) than in layers (92.17%) and broilers (90.98%). Higher prevalence was also noted in females (92.7%) than in males (90.98%) and in intensively managed chickens (93.39%) than in extensively managed chickens (90.69%) with p>0.05. Conventional RT-PCR test was also performed for the molecular detection of virus. The test was done on 52 tracheal swab samples collected from intensive and backyard unvaccinated chickens that were pooled in to 26 samples. Accordingly, 3 (11.54%) of the 26 pooled samples were IBV positive. The result showed that this was the first molecular evidence found in the study area. The seroprevalence of the disease in this study was very high for all age groups, breed types, and farm types. The risk factors mentioned and the management methods may have raised the likelihood of infection and the prevalence of the disease. Vaccination and biosecurity measures are advised to manage the disease. Identification and characterization of persistent IBV serotypes that are present in the field is also recommended to manage the disease.

In Vitro Antioxidant Activities of Plant Polyphenol Extracts and Their Combined Effect with Flaxseed on Raw and Cooked Breast Muscle Fatty Acid Content, Lipid Health Indices and Oxidative Stability in Slow-Growing Sasso Chickens.

Adding flaxseed was found to decrease oxidative stability in feed and increase the antioxidant needs of chicken. This has also been associated with a decrease in the nutritional value and oxidative stability of meat if sufficient dietary antioxidants are not included. Furthermore, dietary flaxseed has been explored in fast-growing chickens as such studies are limited with slow-growing chickens. Thus, this study aimed to evaluate the effects of feeding plant polyphenol extracts as an antioxidant alongside flaxseed on fatty acid content, oxidative stability, and lipid health indices in breast muscle of slow-growing Sasso T451A dual-purpose chicken. A total of 126 chickens assigned to six groups (seven replicates of three) were fed on NC (control and no antioxidants), FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia) and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diet. Feeding on CD8 and VE8 in raw and TS8, CD8 and VE8 diets in cooked breast muscle increased (p < 0.05) the C22:6n − 3 (DHA) and C20:5n − 3 (EPA) contents compared to the FS diet. Feeding FS increased (p < 0.05) the malondialdehyde (MDA) content in breast muscle, whereas TS8 in cooked and raw and CD8 and DA8 diets in raw breast muscle decreased it (p < 0.05). No added benefit was observed in feeding VE8 over plant extracts in terms of improving fatty acid composition and lipid health indices and reducing lipid oxidation in breast meat.

Development of dual-purpose cross for meat and egg production I. Growth performance and carcass composition of the crossbred chickens in comparison to the parent lines

Abstract The aim of the study was to develop a dual-purpose cross suitable for rearing in alternative systems and to examine its growth performance and carcass composition in comparison to the parent lines. The experiment was carried out in the experimental poultry farm in the Institute of Animal Science - Kostinbrod. The cross was developed using females of a layer type line L and cocks from line BB. The latter was based on Bresse Gauloise that is also dual purpose but mainly used for meat. The chickens from the lines and the cross were reared in mixed-sex groups on deep litter, at stocking density of 25 birds/m2, and fed with standard broiler feed until the age of 9 weeks. Then the males were separated and sent to slaughter while the females were left for layers. Crossing hens from layer type line L with BB cocks resulted in dual-purpose chickens with a live weight and feed efficiency that were better in comparison to L line, but lower when compared to the BB line. These parameters were however, lower than the typically observed in this type of poultry. Nevertheless, the chickens displayed good carcass composition and deposited low content of abdominal fat, thus revealing good potential to be successfully realized in market.

The microbiological and sensory status of dual-purpose chickens (Lohmann Dual), male Lohmann Brown Plus chickens, and conventional laying hens slaughtered in a laying hen abattoir compared to conventional broilers slaughtered in a broiler abattoir.

Alternatives to conventional chicken meat and egg production are increasingly under discussion, especially because of the common practice of killing male day-old chicks from laying lines which has been banned from the beginning of 2022 in Germany and is planned to be banned during 2022 in other countries. Production of dual-purpose chicken lines is one possible solution, as such lines combine moderate laying and growth performance. The microbiological status of products from such breeds must be comparable to existing products on the market for food safety purposes. Additionally, the production of such products will take longer because of the feeding regimes required, and again, comparability should be safeguarded for the best consumer protection. The dual-purpose chicken line, Lohmann Dual (males), was compared to males from the laying line Lohmann Brown Plus, conventional laying hens (all slaughtered and processed in the same conventional laying hen abattoir), and conventional broilers (slaughtered in a conventional broiler abattoir). Neck skin samples were taken before chilling at the end of each slaughter line to determine the microbial status of the carcasses. Additionally, fresh and cooked meat sensory analysis was performed on meat from broilers and male and female Lohmann Dual and Lohmann Brown Plus chickens (for three carcasses of each group) at the German Agricultural Society Test Center in Kassel. The focus was on the performance of male Lohmann Dual compared to the other lines. There was no difference in the Enterobacteriaceae count of the dual-purpose chicken line compared to conventional broilers, whereas laying hens had a significantly higher microbial load before chilling, as based on neck skin examinations (p&lt;0.001). According to sensory test results, the meat from dual-purpose chickens was the best (as no defects were found) among the five chicken meat types examined. In conclusion, based on their microbial status and sensory analysis of fresh and cooked meat, Lohmann Dual males slaughtered in a laying hen abattoir can be considered as an alternative to conventionally kept broilers slaughtered in a broiler abattoir.

Multifactorial Evaluation of Regrouping Effects on Performance and Welfare in Two Italian Dual-Purpose Chicken Breeds: Bianca di Saluzzo and Bionda Piemontese.

Simple SummaryLocal chicken breeds Bionda Piemontese (BP) and Bianca di Saluzzo (BS) are promising for use in small-scale poultry farms, which adopt free-range and/or organic farming practice. However, in practical conditions, it can happen that animals are subjected to regrouping, creating a new flock by mixing different groups. Such situations may provoke a stressful response in birds, compromising their welfare. To evaluate the resilience of BP and BS breeds to adverse management practices (regrouping), the present study aimed to assess the birds’ welfare status through a multifactorial approach. As a result, the practice of regrouping immediately compromised the welfare status and the productive performances in both BP and BS hens, but, in the following weeks, birds displayed a reliance, which help them adapt to the new stressful conditions. The aim of the present study was to investigate the ability of two Italian slow-growing poultry breeds (namely, Bionda Piemontese, BP, and Bianca di Saluzzo, BS) to cope with a stressful event, such as collective grouping, using a multifactorial approach. A total of 120 hens of BP and BS breeds were homogenously distributed, according to breed, in 12 pens (10 hens/pen; 6 pens/breed), from 18 to 49 weeks of age. At 50 weeks of age, hens were regrouped (Stressful Farm Practice, SFP), by removing separators, both in indoor and outdoor areas. At 49 weeks of age, 24 hens/breed were randomly selected for the evaluation of welfare (ethological and physiological) parameters, at different time points: T0: 1-week pre-SPF; T1: 1-week post-SFP; T2: 3-week post-SFP; T3: 5-week post-SFP. Egg production was recorded from 38 to 56 weeks of age. Grouping produced a social stress in both BS and BP-laying hens, which was expressed in terms of productive traits (reduction of oviposition), behavioral modification (worsening of plumage condition due to feather peaking and extension of the duration of the tonic immobility test) and physiological modification (increased heterophil/lymphocyte ratio and corticosterone metabolites in droppings). Both breeds reacted in a similar way; in fact, no differences were attributed to the breed. At the end of the observation period, the egg rate fully recovered, while the behavioral and physiological parameters partially recovered but failed to recover to those recorded prior to the stressful event.

Dietary metabolizable energy and crude protein levels affect the performance, egg quality and biochemical parameters of a dual-purpose chicken

Effects of dietary metabolizable energy (ME) and crude protein (CP) level on performance, egg quality and biochemical parameters were studied in a dual-purpose chicken-Beijing You Chicken (BYC) at peak laying period. A 3 × 3 factorial experiment was arranged, including 3 levels of dietary ME (11.31, 11.51, 11.71 MJ/kg) and 3 levels of dietary CP (14%, 15%, 16%). The results showed that dietary CP level alone and the interaction of ME by CP affected the total feed intake (TFI) during 27–30 wks, dietary ME level affected the mortality rate of 27–34 wks of age (p = 0.018), with the highest mortality rate found in 11.31 MJ/kg group (3.10%). The albumen height (AH), Haugh unit (HU) and egg grade (EG) of 16% group was higher than those in 14% and 15% groups (p < 0.05). Serum immunoglobulin G content in 11.31 MJ/kg group was lower than in 11.51 MJ/kg and 11.71 MJ/kg groups (p = 0.037). The present study suggested that dietary levels of 11.51 MJ/kg ME and 16.0% CP are enough to maintain the performance and egg quality of BYC at peak laying period. 11.31 MJ/kg ME increased the mortality of the chicken, which may be related to the decrease of the humoral immune function and antioxidative capability.

Productive performance, perching behavior, keel bone and other health aspects in dual-purpose compared to conventional laying hens

Several alternatives to avoid killing male day-old chicks are available. One of these alternatives is to keep dual-purpose chicken strains. The aim of this study was to compare dual-purpose hens (Lohmann Dual, LD) with conventional laying hens (Lohmann Tradition, LT) in terms of performance, animal welfare parameters such as keel bone state and foot pad dermatitis, and perching behavior. We expected a generally equal or even better performance of the dual-purpose hens except for laying performance. Four hundred female day-old chicks were housed in 6 pens (3 pens per strain) and reared until 54 wk of age. Each pen offered a littered area, elevated slatted manure pit, elevated wooden frame with perches or grids and nest boxes on the manure pit. The wooden frame was alternately equipped with perches or grids. The elevated manure pit as well as the elevated structure was accessible via ramp. Productive performance parameters like mortality, total number of eggs and body weight were assessed periodically. In week 49, 132 hens (66 hens per strain) were randomly selected for radiography of the keel bone and assessment of plumage and foot pad state. Perching behavior was analyzed via scan sampling during rearing and laying period, respectively. Statistical analyzes were done with Linear Mixed Effect Model and General Linear Mixed Model. LD had a higher radiographic density than LT hens (P = 0.0016), other keel bone parameters (fracture score, P = 0.36; deformation, P = 0.83) showed no differences. The vast majority of fractures occurring in both strains were located in the caudal part of the keel bone. During the laying period, usage of elevated structures was higher with grids compared to perches (P < 0.001) and in LD compared to LT (P = 0.01). Some animal welfare problems were less frequent in LD compared to LT hens while other problems did not differ between the 2 strains or were even more frequent in LD hens. Grids may be more suitable as resting area than perches and may possibly help to decrease the prevalence of keel bone damage.

A novel 27-bp indel in the intron region of the YBX3 gene is associated with growth traits in chickens

ABSTRACT 1. The DNA/RNA binding protein YBX3 is associated with gene transcription, DNA repair, and the progression of various diseases and is highly conserved from bacteria to humans. 2. The following experiment found a 27-bp insertion/deletion polymorphism in the intron region of the YBX3 gene through resequencing. In cross-designed, F2 resource groups, the indel was significantly associated with broiler weight and body size at 0, 2, 4, 6, 8, 10 and 12 weeks of age and several other traits (semi evisceration weight (SEW), evisceration weight (EW), semi evisceration rate (SER), evisceration rate (ER), head weight (HW), claw weight (CLW), wing weight (DWW), gizzard weight (GW), pancreas weight (PW), chest muscle weight (CMW), leg weight (LW), leg muscle weight (LMW), shedding weight (SW), carcase weight (CW) and pectoral area (PA)) (P < 0.05). 3. The insertion-insertion (II) genotype was significantly associated with the greatest growth traits and carcase traits, whereas the values associated with the insertion-deletion (ID) genotype were the lowest in the F2 reciprocal cross chickens. 4. The mutation sites were genotyped in 3611 individuals from 13 different chicken breeds and cross-designed F2 resource groups. The II genotype is the most important in commercial broilers, and the I allele frequency observed in these breeds was relatively high. However, there is still considerable potential in breeding dual-purpose chickens and commercial laying hens. 5. The mRNA expression of the YBX3 gene in tissues from different breeds and developmental stages demonstrated that the 27-bp indel may affect the entire development process of poultry by affecting muscle development. These findings are beneficial for elucidating the function of the YBX3 gene and facilitating enhanced production in the chicken industry.

Meat Quality Parameters, Sensory Properties and Consumer Acceptance of Chicken Meat from Dual-Purpose Crossbreeds Fed with Regional Faba Beans.

Consumers’ concerns regarding the ethical and environmental practices of the current poultry production system have led to the search for an alternative production method. This study evaluated samples of three dual-purpose chicken crossbreeds: Vorwerkhuhn × Bresse Gauloise (VBG), Vorwerkhuhn × White Rock (VWR), and Bresse Gauloise × White Rock (BWR), fed with two variants of faba beans (vicin/convicin-rich and -poor: VC+ and VC−, respectively) and soybeans to examine whether the FB-based diets affected the meat quality of the crossbreeds. pH, color, water holding capacity, tenderness, nucleotide content and proximal composition were analyzed instrumentally, whereas sensory properties were identified by a trained panel and product acceptance was evaluated by frequent chicken consumers. Results showed that from instrumental measurements, the yellowness of the samples was affected by the type of feedstuff, whereas most other parameters were affected by the crossbreed, particularly color and nucleotide content. Sensory attributes, specifically, overall chicken aroma as well as firmness and crumbliness, were affected by an interaction of the feedstuff and crossbreed. Consumer preference did not show significant differences between samples. Overall, a faba-bean-based diet appeared to be a suitable alternative to a soybean-based diet on the crossbreeds VBG, VWR, and BWR when assessing the overall quality and taste of chicken breasts.

Effect of a reciprocal cross between local and commercial chickens on hatchability and estimating some genetic parameters

This study was carried out at Kani Graw field –around Erbil city during the breeding season 2021 by using two genetic groups of chickens, Kurdish local chickens (KK) and Super Harco commercial dual purpose chickens (HH), which were reciprocally mated to produce four combinations ( HH , KK ,HK and KH) to estimate crossbreeding effects, general combining ability (GCA) and specific combing ability (SCA), heterotic effect percent (H%), and direct additive effect (DAE) for hatching traits in pure chickens and their crosses. Furthermore, GCA and SCA were also used to estimate breeding value (BV) and genetic value (GVFM) for two parents and their crosses. The results indicated that significant differences among genetic groups in fertility percentage (F%) and chick weight (CW) however did not observe any significant differences in egg weight (EW) , hatchability of total eggs percentage (HTE%) and embryonic dead rate (ED%). However there were no significant difference between H×K cross and it's reciprocal K ×H in EW, HTE% , F% and ED% traits, furthermore, the reciprocal crosses(K×H) had recorded statistically the highest values for HTE%, F% and CW compared to the other genotypes, the KK genotype was recorded positive values of GCA for EW , HTE% , F% and ED% traits.. the reciprocal crosses (K × H ) was recorded the positive and high estimates of SCA for HTE % , F % and ED % traits while, H x K had the highest positive estimates for EW trait compared to the other genotypes. percentages of Heterotic (H %) for the H x K cross and K x H reciprocal were recorded positive values of HTE% ,F% and ED% traits were found. On the other hand both cross and reciprocal were negative value for CW . The KK genotype had significant and positive values of direct additive effect (DAE) for F% and ED % traits. Both of the HH and KK genotypes had negative value of DAE for CW trait, KK strain and H× K cross had the highest expected breeding values for HTE% and F % traits. both of HH , KK and H×K genotypes had the negative breeding values for EW and CW, while, K×H reciprocal had the highest values of HTE% , F% and ED % traits. In addition , genetic value of KS had the highest value in H% , F% and ED% .

Genetic effect of an InDel in the promoter region of the NUDT15 and its effect on myoblast proliferation in chickens

BackgroundMolecular breeding accelerates the speed of animal breeding. Screening molecular markers that can affect economic traits through genome-wide association studies (GWAS) can provide a theoretical basis for molecular breeding. At present, a large number of molecular markers have been screened in poultry research, but few reports on how molecular markers affect economic traits exist. It is particularly important to reveal the action mechanisms of molecular markers, which can provide more accurate information for molecular breeding.ResultsThe aim of this study was to investigate the relationships between two indels (NUDT15-indel-2777 and NUDT15-indel-1673) in the promoter region of NUDT15 and growth and carcass traits in chickens and to explore the regulatory mechanism of NUDT15. Significant differences were found in genotype and allele frequencies among commercial broilers, commercial laying hens and dual-purpose chickens. The results of association analyses showed that these two indel loci could significantly affect growth traits, such as body weight, and carcass traits. Tissue expression profiling at E12 showed that the expression of NUDT15 was significantly higher in skeletal muscle, and time-expression profiling of leg muscle showed that the expression of NUDT15 in myoblasts was significantly higher in the E10 and E12 proliferation stages than in other stages. Promoter activity analysis showed that pro-1673-I and pro-1673-D significantly inhibited promoter activity, and the promoter activity of pro-1673-D was significantly lower than that of pro-1673-I. In addition, when NUDT15 was overexpressed or underwent interference in chicken primary myoblasts (CPMs), NUDT15 could inhibit the proliferation of CPMs.ConclusionThe results suggest that the studied indels in the promoter region of NUDT15 may regulate the proliferation of CPMs by affecting NUDT15 expression, ultimately affecting the growth and carcass traits of chickens. These indel polymorphisms may be used together as molecular markers for improving economic traits in chickens.

Evaluation of Mewari, a native chicken breed vis-à-vis Pratapdhan, an improved chicken variety under an intensive system of rearing

Mewari is an indigenous chicken breed and Pratapdhan is a dual purpose chicken variety developed using Mewari, coloured broiler and Rhode Island Red. Pratapdhan birds were well accepted by the farmers of Rajasthan and adjoining areas. The study was undertaken for comparative evaluation of Mewari and Pratapdhan chicken under intensive system. The data were analyzed using factorial design with genotype, sex and generation (2 × 2 × 3) as main effects. The body weights differed significantly at all ages with significant higher weights in Pratapdhan as compared to Mewari chicken. Sex had significant effect on body weights at all ages except at 2nd week. Males had significantly higher body weights across the genotypes and generations. The interaction effects were significant between the genotypes, sex and generations, except at 2nd week of age. The body weights showed an increasing trend over the generations with few exceptions. ASM and egg weights significantly varied between the genotypes and across the generations with significant interaction effects. The average annual egg production and egg weight (72 weeks) in Mewari and Pratapdhan chicken were 92.02±0.52 and 158.25±1.20 and 46.85±0.22 and 55.74±0.28, respectively. The fertility per cent was 80.39±1.45 and 83.28±0.64 in Mewari and Pratapdhan, respectively. The results suggest that Pratapdhan could be one of the potential improved germplasm for backyard poultry production.

Comparison of meat quality attributes of improved native chicken varieties Vanaraja and Indbro with Commercial broiler chicken

There is great demand for native chicken meat due to its unique strong flavour, firm and hard texture and lower fat content and fetches almost thrice the price of broiler meat. During the last few years, improved native chicken varieties are being introduced to meet the demand and the market share is steadily increasing. The present study was conducted to compare the carcass characteristics and meat quality attributes of improved native chicken varieties viz., Vanaraja (dual purpose chicken) and Indbro (slow growing coloured broiler) with Commercial broilers. In this study, total of 30 birds, comprising 10 birds each from Vanaraja (56 days old), Indbro (49 days old), and Commercial broilers (38 days old) at their respective marketable age were selected for evaluation. Analysis of carcass traits revealed significantly (P&lt;0.05) higher live wt, dressed carcass wt, and breast yield (% of live wt) for Commercial broilers compared to Indbro and Vanaraja birds, whereas the yield of legs, wings, and neck (% of live wt) were higher for Vanaraja birds compared to other groups of birds. The results of meat quality parameters like proximate composition revealed significantly (P&lt;0.05) higher % of moisture, protein, and ash for meat of Vanaraja birds compared to other groups, whereas fat % was significantly (P&lt;0.05) higher in Commercial broilers. Significantly (P&lt;0.05) higher redness (a*) values, lower lightness (L*) values, higher muscle fibre diameter and hydroxyproline content was noticed in Vanaraja birds compared to other groups. Commercial broiler chicken meat showed significantly (P&lt;0.05) higher pH, TBARS and water holding capacity (%) values compared to other groups. Sensory evaluation scores for cooked breast meat samples revealed comparatively higher appearance, flavour, juiciness, texture, and overall acceptability scores for Vanaraja and Indbro birds than Commercial broilers. Shear force values were significantly (P&lt;0.05) higher for Vanaraja followed by Indbro and then Commercial broilers. Microbial analysis indicated lower total plate count (TPC), yeast and mould and psychrotrophic counts for Commercial broilers. The results of study indicated that though the Commercial broilers have better carcass traits compared to Vanaraja and Indbro birds, these improved native chicken varieties have better meat quality attributes and have potential to form a significant source of chicken with better sensory attributes.

ECLOSIÓN, MUERTE EMBRIONARIA Y CRECIMIENTO DE POLLITOS EN GALLINAS DOBLE PROPÓSITO Y DE RIÑA BAJO CONDICIONES HIPOBÁRICAS NATURALES

The present study aimed to compare results for hatchability and growing performance of chicks from 2 biotypes, dual purpose (DP) and brawl (BR), in hipobaric conditions (2718 m above sea level). In experiment 1, a total of 352 hatching eggs were randomly arranged, 176 egg of DP y 176 BR. In experiment 2, a total of 114 one-day-old unsexed chickens were reared for 28 d. The experimental design for hatchability and chick performance variables was completely randomized with 2 treatments (DP and BR). There were no differences between the studied treatments for hatchability results (p&gt;0.05). Hens’ biotype affected chicken performance in the rearing phase (p&lt;0.01), where the DP chickens had better body weight and feed conversion than BR, but BR chickens had lower mortality than DP chickens.

Association of insulin-like growth factor 1 (IGF1) gene polymorphism with the reproductive performance of three dual-purpose chicken breeds.

The study was designed to investigate the association of Insulin-like growth factor 1 (IGF1) gene polymorphism with the reproductive performance of FUNAAB-Alpha, Sasso, and Kuroiler dual-purpose chicken breeds. To achieve this, a total of 250 healthy hens were selected at 12 wk of age and were intensively managed in cages for 52 wk. Blood sample was taken from each chicken at the 34th week and genomic DNA was extracted using Qiagentm DNA extraction kit, PCR was used to amplify the DNA fragments, and the PCR products were electrophoresed. Amplicons obtained were digested with restriction enzyme hinf1, and were further electrophoresed on 1.5% agarose gel. Data obtained were analyzed using the General linear model of SAS (2002) version 9.0 to determine the effect of IGF1 gene polymorphism and the distribution of alleles within the breeds. Results show polymorphism of the IGF1 gene and the restriction analysis indicated two alleles; A 58% and C 42% with the identification of genotypes AA, AC, and CC, and genotypic frequency of 22%, 43%, and 35%, respectively. Significant associations were observed between the polymorphism of the IGF1 gene, age of the bird at first lay, and weight of the hen at first lay. Chickens with haplotype CC came earlier into lay compared to those with the other two haplotypes (AA and AC). Therefore, the study suggests that haplotype CC could be used as a genetic marker to select for an improved laying performance in chickens.

A 104-bp Structural Variation of the ADPRHL1 Gene Is Associated With Growth Traits in Chickens

Analyzing marker-assisted breeding is an important method utilized in modern molecular breeding. Recent studies have determined that a large number of molecular markers appear to explain the impact of “lost heritability” on human height. Therefore, it is necessary to locate molecular marker sites in poultry and investigate the possible molecular mechanisms governing their effects. In this study, we found a 104-bp insertion/deletion polymorphism in the 5′UTR of the ADPRHL1 gene through resequencing. In cross-designed F2 resource groups, the indel was significantly associated with weight at 0, 2, 4, 6, and 10 weeks and a number of other traits [carcass weight (CW), semi-evisceration weight (SEW), evisceration weight (EW), claw weight (CLW), wings weight (DWW), gizzard weight (GW), pancreas weight (PW), chest muscle weight (CMW), leg weight (LW), leg muscle weight (LMW), shedding Weight (SW), liver rate (LR), and leg muscle rate (LMR)] (P < 0.05). In brief, the insertion-insertion (II) genotype was significantly associated with the greatest growth traits and meat quality traits, whereas the values associated with the insertion-deletion (ID) genotype were the lowest in the F2 reciprocal cross chickens. The mutation sites were genotyped in 4,526 individuals from 12 different chicken breeds and cross-designed F2 resource groups. The II genotype is the most important genotype in commercial broilers, and the I allele frequency observed in these breeds is relatively high. Deletion mutations tend to be fixed in commercial broilers. However, there is still considerable great potential for breeding in dual-purpose chickens and commercial laying hens. A luciferase reporter assay showed that the II genotype of the ADPRHL1 gene possessed 2.49-fold higher promoter activity than the DD genotype (P < 0.05). We hypothesized that this indel might affect the transcriptional activity of ADPRHL1, thereby affecting the growth traits of chickens. These findings may help to elucidate the function of the ADPRHL1 gene and facilitate enhanced reproduction in the chicken industry.

Fatty acid profiles and omega-3 long-chain polyunsaturated fatty acids (LC-PUFA) biosynthesis capacity of three dual purpose chicken breeds

Westernized societies ingest an unhealthy high dietary omega-6/omega-3 fatty acid ratio of 20:1 or even higher. Seafood is the primary source of omega-3 long chain polyunsaturated fatty acids (LC-PUFA) for humans, mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are involved in a plethora of physiological and health-related processes. However, the production of marine organisms with aquafeed formulations based on marine ingredients leads to serious environmental impacts on global pelagic fish resources, resulting in an unsustainable activity. The present study aims to gain further insight into the metabolism of fatty acids in chicken as a potential supply for omega-3 LC-PUFA. To this purpose, lipid classes and fatty acid profiles of thighs and hepatocytes, and the modification of [1-14C]18:3n-3 by hepatocytes isolated from three dual-purpose chicken breeds adapted to free-range culture systems were determined. Arachidonic acid highly accumulated in thighs meat (7.16–8.79 %) despite being barely supplied in the diet, with DHA (1.22–1.71 %) and n-3 docosapentaenoic acid (DPA, 22:5n-3; 1.02–1.14 %) being also relevant. Our experimental design with radiolabeled fatty acids was validated for the first time in terrestrial vertebrates. Chicken hepatocytes incubated with [1-14C]18:3n-3 produced a wide variety of C18-C24 intermediates demonstrating that the set of fatty acyl desaturases and elongases enzymes necessary to metabolize dietary C18 precursors are active for the production of LC-PUFA, including EPA, n-3 DPA and DHA.

Effects of an Elevated Platform on Welfare Aspects in Male Conventional Broilers and Dual-Purpose Chickens.

To avoid killing day-old male chicks, one possibility is to keep dual-purpose chicken strains. Here, the hens were kept for egg production, and the roosters were kept for meat production. Both sexes had moderate performances compared to the respective hybrid chicken strains. However, until now, little has been known about whether male dual-purpose chickens may profit from enrichment in the environment in which broiler chickens are raised under conventional conditions. This study aims to further investigate the suitability of elevated structures for dual-purpose chickens (Lohmann Dual) with moderate growth and for fast-growing male broiler chickens (Ross 308). In two consecutive trials, we kept 686 Ross and 672 Dual chickens in 24 compartments (2 trials × 2 strains × 6 compartments). Half of the compartments were equipped with elevated grid platforms at a height of 50 cm (enriched group). In the other half of the compartments, no platforms were installed (control group). We analyzed the usage of the elevated platforms by scan sampling and assessed animal-based (walking ability, plumage cleanliness, and foot health) and management-based (litter quality) indicators. Both strains showed increasing use of the elevated platforms from the first week of life onwards. However, the fast-growing chickens used the elevated platform less than the slow-growing chickens. At the end of the fattening period, the birds used the elevated grids more at night than during the daytime. Slow-growing chickens kept in enriched compartments showed a better walking ability. In general, slow-growing chickens had better plumage conditions and foot health compared to fast-growing chickens. Our results show that natural behaviors such as perching can be supported by offering elevated platforms and that animal-based indicators such as walking ability can be improved, at least in slow-growing chickens. Moreover, the use of an alternative chicken strain avoids killing day-old male chicks, and in addition, these chickens show fewer animal welfare problems than a conventional fattening strain. Thus, the use of male chickens of a dual-purpose strain can substantially contribute to improving animal welfare in broiler meat production.