Egg Production In Layers Research Articles

Integrated transcriptomic hypothalamic-pituitary-ovarian axis network analysis reveals the role of energy availability on egg production in layers

Energy is a crucial component for maintaining egg production in layers. The hypothalamic-pituitary-ovarian (HPO) axis is an energy-sensitive functional axis for follicle development, synthesis, and secretion of reproductive hormones, and plays a key role in modulating sustained ovulation in layers. To investigate the mechanism of integrated network regulation of the HPO axis under energy fluctuation, ninety Hy-line brown layers (265-day-old, 1.92 ± 0.02 kg) were randomly divided into three groups for an 17-day experiment: a control group (Con group) fed ad libitum from days 1 to 17, an energy deprived group (ED group) that was fed ad libitum from days 1 to 12 and then underwent a fasting period from days 13 to 17 to induce a pause in laying, and a re-fed group (Rf group) that fasted for seven days (specifically, days 1 to 5, day 7, and day 9), had ad libitum access to feed on days 6 and 8, and were continuously fed from days 10 to 17. Each treatment consisted of 10 replicates with 3 birds per replicate. The study found that energy deprivation significantly decreased reproductive performance such as egg laying rate, ovarian index, number of small yellow follicles (SYF), and normal hierarchical follicles (NHIE) (P < 0.05), which recovered after refeeding, indicating the importance of energy availability for sustained ovulation in layers. In addition, estradiol (E2), estradiol/progesterone ratio (E2/P4), and luteinizing hormone (LH) displayed changes similar to follicle number, whereas follicle-stimulating hormone (FSH) exhibited a contrasting pattern. Transcriptome analysis revealed that energy deprivation downregulated genes related to energy and appetite-regulated neurotransmitter receptors and neuropeptides in the hypothalamus. These signals combined to inhibit gonadotropin-releasing hormone (GnRH) secretion and subsequently downregulated the crucial genes responsible for synthesizing gonadotropins, gonadotropin releasing hormone receptor (GnRHR), and glycoprotein hormones alpha chain (CGA). Consequently, this suppression of the hypothalamus and pituitary affected ovarian function through ovarian steroidogenesis and the extracellular matrix (ECM)-receptor interaction. These findings suggest that energy deprivation inhibits the function of the HPO axis, leading to impaired follicle development and reduced egg production and that refeeding can partially restore these indicators.

Effects of Liquid Whey Supplementation with Water on Egg Production and Egg Quality in Layer Chickens

Background: Liquid whey is a milk by-product and contains good quality protein and minerals. Due to lack of proper knowledge and sufficient technology it remains unutilized and thrown away as a waste. So, keeping in view of its profitable utilization, a study was planned to include liquid whey as feed supplement to layer poultry. Methods: A study was conducted by supplementation of liquid whey to layer chickens to study the effect on egg production and egg quality. A total of 120 layer birds (indicate the age) were supplemented with liquid whey ad libitum in the drinking water @ 0, 5, 10 and 15% up to 90 days. The data were collected with respect to egg production and egg quality parameters. Result: Supplementation of liquid whey in drinking water improved egg production and egg quality in laying chickens. It may be concluded that liquid whey can be supplemented with drinking water at the rate of 5% (v/v) for better egg production in layers and for production of premium quality of bigger size and weight of eggs, supplementation of whey up to 15% (v/v) can be recommended.

3 Overview of Poultry Modeling Evolution

Abstract This presentation aims to review advances in mathematical models used in poultry nutrition and production in the past decades and present an overview of the current status. Models have been developed to improve understanding of growth, voluntary feed intake, nutrient utilization, body composition, responses to nutrient supply, environmental changes, and stressors. Growth models for broilers, turkeys, ducks, layers, and breeders are available mainly based on the Gompertz curve, but a few other mathematical functions are also used. A few models can simulate egg production in layers and breeders. The EFG and Avinesp models, tools from feed additive and genetic companies, among others, will be described or mentioned. These models can describe genetic differences and estimate energy, amino acids, calcium, and phosphorus requirements or multiple biological responses to specific nutrient levels. Most models use the concept of ideal protein or balanced protein to describe responses to amino acid levels. However, very few models can describe responses to modifications of one or two specific amino acids. Compartmental models are mainly based on main chemical components such as water, body and feather protein, fat, and ash. Poultry models seldom consider variability due to feeding ingredient quality, fiber, fat, other mineral composition, or variation in nutrient digestibility. However, some models can predict responses to exogenous enzymes. Most applications can predict body weights and yields at a specific age, and some can estimate nitrogen, calcium, and phosphorus excretion. These models can be integrated with feed formulation software, economic data, and optimizers to simulate multiple conditions and estimate biological, economic, and environmental optimums. Poultry enterprise models can describe the whole production system, estimate the optimum combination of resources, aid in planning and scheduling, and determine strategies for growth. Currently, no official recommendations from academic or private groups are based only on models to estimate nutrient levels. Combinations of empirical data and model results are frequently used for nutritional decision-making. A few tools are available for specialized personnel to decide the energy and amino acid levels to use. The application of electronics and telecommunications triggered the fast production of enormous volumes of data from diverse poultry production sectors. This big data avalanche is starting to help modelers to integrate more accurate information and incorporate natural variability. However, integration between current models and significant data results is still under development. Despite increasing international collaboration in modeling, poultry model developments keep great independence and fundamental differences. One critical issue needed for faster development of poultry modeling is to increase education in modeling. The lack of academic programs offering modeling classes related to poultry caused the low current application of models. However, awareness about the benefits of modeling has increased in the past few years, and efforts are under development.

N-carbamylglutamate supplementation induces functional egg production in layers by modulating liver transcriptome profiles

Eggs rich in polyunsaturated fatty acids (PUFA), known as functional eggs, are animal products deemed beneficial to human health and possess high economic value. The production of functional eggs involves supplementing exogenous additives with the ability to regulate lipid metabolism. As N-Carbamylglutamate (NCG) serves as an endogenous arginine synthesizer, and arginine acts as the substrate for the formation of nitric oxide (NO), the biological function of NCG is partially mediated by NO. NO is a key regulatory molecule in lipid metabolism, suggesting that NCG may also have the ability to modulate lipid metabolism. In order to assess the capacity of NCG in regulating liver lipid metabolism and its potential application in producing functional eggs, we conducted a study to investigate the effects of dietary supplementation of NCG on production performance, serum, and liver NO levels, yolk fatty acid composition, and the liver transcriptome of layers. In this study, we utilized 30 layers of the Jinghong No.1 breed, all aged 45 wk. All the birds were randomly divided into 2 groups. Each group had 5 replicates, and each replicate had 3 birds. We provided them with different diets: one group received the basic diet, and the other group's diet was supplemented with 0.08% NCG. The experiment lasted for 14 wk. The results did not reveal any positive impact of NCG on production performance. However, NCG supplementation elevated NO levels in serum and liver, along with an increase in yolk PUFA, ω-3, and ω-6 fatty acids. Liver transcriptome analysis identified 124 upregulated differentially expressed genes (DEGs) and 43 downregulated DEGs due to NCG supplementation. Functional annotation using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database highlighted 3 upregulated DEGs (CPT1A, MOGAT1, and CHKA) and 2 downregulated DEGs (FASN and ETNPPL) associated with lipid metabolism. Pathway enrichment analysis revealed that CPT1A was enriched in the AMPK signaling pathway and the PPAR signaling pathway, while FASN was enriched in the AMPK signaling pathway. Thus, CPT1A and FASN are potential functional genes related to lipid metabolism facilitated by NCG supplementation. In summary, our study suggests that NCG supplementation modulates liver lipid metabolism, leading to the production of functional eggs in layers.

Review on application of probiotics in poultry farm

Poultry farming, raising of birds domestically or commercially, primarily for meat and eggs but also for feathers. In poultry industry, probiotics applications have widely been shown to improve the barrier function of intestine and reduce pathogenic problems in gastrointestinal tract thus leading to the enhancement of immune response and replacement of sub-therapeutic antibiotics. Probiotics, the novel feed or food supplements are naturally occurring beneficial live microbes including bacteria, fungi and yeasts. Probiotics are proven to improve the health and wellbeing of birds. As a group of growth promoters, the addition of probiotics to the diet of poultry has been found to improve growth performance, feed conversion efficiency, immune responses and help in combating enteric pathogens. The addition of probiotics to poultry diet also improves egg production in layers. Three basic mechanisms of probiotics include competitive exclusion of pathogenic microbes, production of antibacterial substances and immune modulation of host. Generally, live a pathogenic microbial strain, singly or as multistrain probiotics, belonging to genus Lactobacillus, Streptococcus, Bacillus, Enterococcus, Pediococcus, Aspergillus and Saccharomyces are used in poultry. The injudicious and prolific use of sub-therapeutic levels of antibiotics in animal feed to suppress or eliminate harmful organisms, and to improve growth and feed efficiency, have paved way for their presence as residues in animal by-products and have also given rise to drug resistant microorganisms. Because of public health concerns, nowadays, the use of probiotics as substitute for antibiotics in poultry production has become an area of great interest. The present article reviews the beneficial effects and potential applications of probiotics or direct fed microbial (DFM) on health and production performances in poultry.

Could Insect Products Provide a Safe and Sustainable Feed Alternative for the Poultry Industry? A Comprehensive Review.

The planet is home to more than 2000 species of edible insects, some of which have been consumed as food for many years. Recently, edible insect products have been gradually increasing in several countries, such as Italy and Egypt, as novel feed resources for humans and animals due to their availability, potential economic benefits, and high nutritive value. The insect industry can provide a new solution for livestock nutrition and offer many additional advantages, but there are obstacles to overcome, such as some nutritional organizations that forbid its usage. Nevertheless, previous research indicates that different insect species could be used safely as nutraceuticals in poultry farming to improve broiler growth performance (>3%) and layer egg production (>5%). Among these species, there are various products and extracts that can be used in poultry nutrition in a sustainable manner. This review provides an outline of insect composition, nutrient values, application in poultry feed, safety, and guidelines, and finally, the future perspectives of insects as an alternative feed source in poultry diets.

EARTHWORM MEAL: A NOVEL NON-CONVENTIONAL FEED INGREDIENT FOR SUSTAINABLE POULTRY PRODUCTION

The poultry industry is one of the most important/vibrant sectors in the livestock industry. Feed economics is highly important in the production of poultry, especially in intensive farming. Protein intake is the key factor for the sustainable production process and growth rates. Mainly soybean and fish meal is used to fulfill the protein requirements in poultry feed, however, currently, soybean meal and other conventional protein ingredients are facing the problem of shortage supply resultantly increasing in prices. So, there is an urgent need to explore other alternatives and cheaper protein sources. In the past 20 years, amongst different alternative protein sources, private companies and research institutes have focused on the use of algae, insects, and other invertebrates in poultry diets whereas particular attention needs to be paid to the dietary use of earthworms as it is agood and palatable source of protein. Earthworms can be successfully used as an alternative protein source for poultry and aquaculture as an environmentally friendly protein feed ingredient. In this review, we summarize the suitability, productivity, and effectiveness of earthworm meals as an alternative protein ingredient in poultry diets The research has investigated the use of earthworm meal in fish and poultry feed and exhibited an increase in body weight, feed conversion ratio, feed intake, and growth rates in broilers as well as an increase in egg production in layers. The research has shown dietary inclusion level of earthworm meal in the fish diet is successfully up to 25-30% whilst its inclusion level in the broiler diet should not go beyond 15%. Supplementation of earthworm meals in broiler and aquaculture diets may trigger production performances without affecting the quality of the final product. The goal of this review is to deliver the recent scenario of research on earthworm meal; to offer a better understanding of its use as a novel feed ingredient for sustainable poultry production.

Applications of Myostatin in Poultry and Aquaculture - A Review

Polymorphism is an important component of animal genetic improvement. As a result, myostatin gene is largely involved in muscle formation and growth and is a great candidate gene for increased growth of muscle in animals. Myostatin negates the growth of muscle cells and is found across species. Literature shows various applications and importance of myostatin in poultry and aquaculture production. In poultry, variations in the myostatin gene have been linked to growth characteristics. In aquaculture, myostatin influences the enhancement of the muscle tissues of fish. Besides, myostatin plays a role in increasing the lipid content of muscle, lowering circulating glucose levels, and hepatosomatic index in fish. Studies on zebrafish as a model species have confirmed myostatin involvement in the muscle development of fish. Its expression is not limited to skeletal muscle but also occurs in the liver, brain, and other organs. In the myostatin-b-deficient zebrafish, the size of visceral adipose tissues shrank, and more lipids have been observed to accumulate in skeletal muscle than in wild-type fish. The inhibition or complete depletion of functional myostatin is known to cause the “double-muscled” in several cattle breeds and similar traits in other species. However, the “double-muscled” animals have captured the attention of breeders and researchers due to the enhanced muscular tissues; associated with productivity issues. For instance, the effect of myostatin inhibition has been associated with egg production. When compared to wild-type, myostatin homozygous mutant birds had a significantly delayed commencement of egg production in layers. It is therefore imperative to increase the knowledge of myostatin molecular genetics and bioactivity in various tissues in the poultry and aquaculture sector. This will enable improved productivity and enhanced contribution of animal-sourced proteins from both sectors of animal production.

Effect of boron supplementation on laying performance of White Leghorn hens fed diet with and without adequate level of calcium.

This study was conducted in White Leghorn layers to ascertain the effect of boron (B) supplementation to calcium (Ca) inadequate diet under standard managemental practices. A total of 80 commercial White Leghorn hens, 25weeks old with a uniform body weight, were randomly assigned to one of the 4 groups of 20 hens/replicates in each dietary group viz., normal calcium (NC)/Ca adequate, low calcium (LC)/Ca-inadequate, normal calcium with 40ppm B (NCB) and low calcium with 40ppm B (LCB). Dietary level of Ca was maintained at two levels, 100 (normal) and 90% (inadequate) of the requirement. Supplementation of B at 40ppm improved (P < 0.01) egg production of layers from third month of trial as compared to un-supplemented group. Feed conversion ratio of layers was positively (P < 0.05) influenced by B supplementation in Ca-inadequate diet. Egg shell thickness of layers was found to be higher (P < 0.001) in groups supplemented 40ppm B, irrespective of the level of Ca in the diets. Cracked egg production was also significantly (P < 0.01) lower in B-supplemented groups compared to Ca-inadequate group. Boron supplementation improved Ca retention irrespective of dietary Ca level. Low-Ca diet without boron supplementation resulted in lower retention (P < 0.05) of magnesium and boron. It is concluded that supplementation of 40ppm B to Ca-inadequate diet ameliorated the lower laying performance in layers and confirms the usefulness of B in such abiotic stress situations.

Effect of white and yellow cassava root meal diets supplemented with different additives on performance of layers and the quality of eggs laid.

A 30-week experiment was conducted to investigate the effect of dietary supplementation of 2 varieties of cassava root meal (CRM) with various additives on performance characteristics of laying birds and the quality of eggs laid. Two hundred and forty 21-week-old (Isa Brown®″ strain) laying birds were allotted to 8 dietary treatments in a 2 × 4 factorial arrangement of white (TME 419) and yellow (ITA/IBD/1368) CRM supplemented with no additive, amino acids (methionine and lysine), enzyme, and amino acids + enzyme (AA + Enz). The experiment was partitioned in 3 phases: 0-10 weeks, 11-20 weeks, and 21-30 weeks in lay. Variety effect showed improved (p < 0.05) egg production in layers fed with yellow cassava than those fed the white variety. Supplementing yellow cassava root meal (YCRM) and white cassava root meal (WCRM) with AA + Enz from 0 to 10weeks in lay and 11 to 30weeks in lay, respectively, resulted in superior egg production performance at a reduced cost. Feeding the layers with diets containing the two varieties of cassava, with or without additives at the three phases of lay, did not compromise the quality of eggs produced and YCRM did not improve the egg yolk colour. It was concluded that egg production was improved by diets containing YCRM at the 3 phases of lay, and WCRM supplemented with AA + Enz improved egg production only from 11 weeks in lay. The 2 varieties of cassava root meal and the various additives used did not affect the quality of the eggs laid by the layers.

Antibiotic Treatment and Antibiogram Profiles of E.coli Isolated from Selected Poultry Farms in Ido-Ekiti

Aims: Antibiotic therapy in poultry is alleged to spread multiple antibiotic resistant bacteria. This study seeks to correlate antibiotic treatment in poultry with the occurrence of multiple bacterial resistances to critically important antibiotics and also determine the potential sources of acquisition of these bacteria.&#x0D; Study Design: Experimental design.&#x0D; Place and Duration of Study: Department of Microbiology, Ekiti State University, Ado-Ekiti between February 2017 and December 2019.&#x0D; Methodology: Data on antibiotic treatment, poultry management practices and use of natural water bodies in the area of study were collected from farm managers and residents using a questionnaire. The locations of the source area and their relative distances were determined using the Geographical System Information Software, Mapit. Fresh fecal droppings from poultry birds were randomly sampled with a sterile swab stick and transferred into a freshly-procured, sealed, factory-packed polythene bag. Farm feed, water, and soil from disposal sites were also collected in sterile universal containers. The suspension of the fecal droppings was streaked on Eosin Methylene Blue agar plates with sterile wire loop and incubated at 37 °C for 18-24 hours. Soil and water samples from the waste disposal sites were serially diluted and streaked as previously. The isolates were characterized using relevant biochemical tests. Modified Kirby Bauer method was used to determine the isolates’ susceptibility to nine tested antibiotics, and the results were interpreted based on CLSI guidelines.&#x0D; Results: Most of the examined birds, (92%) were exposed to antibiotics, of which 64% of the antibiotics were administered for therapeutic purposes, prophylaxis (27%) and enhancement of egg production in layers (9%). All the antibiotics were administered by mixing them in a specified quantity of water. The majority (46%) of the birds were first exposed to antibiotics at the age of 2 weeks. Routine charts were used by 25% of the farmers for the administration of antibiotics. Data from farm records show that eleven antibiotics were selectively used on the farms. Sulfonamide and diaveridine, an anti-coccidiostat, were administered in most of the farms (50%), while tylosine, metronidazole and chloramphenicol recorded the least (8.3%). Carbapenem, penicillin, and cephalosporin were not administered. From the data obtained on antibiotics-presence in two retail markets, tetracycline, neomycin, gentamycin and erythromycin were available in both retail markets, cephalosporins, meropenem, and metronidazole were not sold for poultry consumption. Both the percentage occurrences of E. coli from fresh poultry droppings (44.1%) and waste disposal sites (33.3%) were relatively low. Higher antibiotic percentage resistance to ciprofloxacin (87%), ofloxacin (83%), sulfonamide, and tetracycline (78%) were found in the isolates. Multiple antibiotic-resistant profiles occurred in patterns and different patterns were replicated across various farms. Also, 46 multiple antibiotic-resistant patterns were recorded, and two of these patterns (AMC, CIP, OFX, CN, SXT, TET and CRO, CAZ, AMC, CIP, OFX, CN, MEM, SXT) were spread across 50% of the farms. There was history of diarrhea in some respondents (12%), linked to human exposure to contaminated natural water bodies. From correlation studies, both data on antibiotic treatment and that from market survey were directly related to the antibiotic-resistant profiles of isolates. The Spearman correlation coefficient are (rs (3) = 0.866, p = .333) and (rs (3) = 0 .667, p = .500) respectively.&#x0D; Conclusion: The development and spread of multiple antibiotic-resistant bacteria of poultry origin are primarily attributed to poor antibiotic formulation policy, crude antibiotic treatment on poultry farms, and indiscriminate supply of antibiotics to untrained poultry personnel. The effectiveness of the super drugs used for the treatment of superbugs in poultry birds may be undermined if policies on the antibiotic formulation, dispensing, and therapy are not reviewed.

The effect of high monacolin K red yeast rice supplement on performance, egg quality, egg yolk cholesterol, plasma lipids and enzyme profile of laying hens

Context Reducing egg cholesterol has been a major goal of many researchers over four decades. Monacolin K, a 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitor, identical to the active ingredient in the prescription statin drug lovastatin, could be a promising feed supplement for layers. Aims To determine the effects of high monacolin K red yeast rice (RYR) supplement on feed intake, egg production, egg cholesterol content, plasma lipid and enzyme metabolites in laying hens. Methods Hyline brown layers were fed RYR supplement at 0, 0.2, 0.4, 0.8 and 1.6% of the diet for 6 weeks. Total and daily feed intake, egg production, egg weights and feed conversion ratio between the RYR treated groups and the control were compiled. Egg cholesterol and egg quality at the 3rd and 6th week of the feeding trial were analysed. Plasma lipids and enzymes were sampled towards the end of the trial. Key results Egg cholesterol were significantly lower (P &lt; 0.05) in the 0.8 and 1.6% RYR supplemented group. Supplementation with 0.8% RYR resulted in 11.16% reduction in egg cholesterol at the 3rd week with no further improvements with longer feeding. There were no significant differences (P &gt; 0.05) in total and daily feed intake, egg production, egg weights and feed conversion ratio (FCR) between the RYR treated and control group. Total plasma cholesterol and triglycerides were significantly lower (P &lt; 0.05) in the 0.8 and 1.6% RYR supplemented group when compared with the control group. RYR supplementation exert no significant differences (P &gt; 0.05) in plasma enzyme levels. Conclusions The present study suggests that RYR supplementation of 0.8% resulted in egg cholesterol reduction by 11.16% with no adverse effects on laying hens. Implications The feeding trial showed that RYR supplement can be used as a feed additive in layer diets to lower egg cholesterol, plasma cholesterol and triglycerides with no adverse effects on layer egg production and plasma enzymes over the feeding period.

Complete Genome Sequences of Seven Avibacterium paragallinarum Isolates from Poultry Farms in Pennsylvania, USA.

Avibacterium paragallinarum, the causative agent of infectious coryza, causes significant economic losses to the poultry industry due to increased culling rates in growing chickens and decreased egg production in layers. We present the complete genome sequences of seven strains of Avibacterium paragallinarum isolated from poultry farms in Pennsylvania during 2019.

Infectious Coryza: Persistence, Genotyping, and Vaccine Testing.

The reemergence of infectious coryza (IC) caused by Avibacterium paragallinarum (AP) as an acute and occasionally chronic respiratory disease in domestic poultry has caused severe losses in several U.S. states. The disease is also associated with decreased egg production in layers and increased condemnations from air sac infections in broilers. A series of applied experiments were performed to elucidate the persistence of AP in infected broiler flocks, to genotype AP strains isolated from field cases, and to evaluate commercial and autogenous vaccine protection in commercial and specific-pathogen-free (SPF) chickens. Experimental evaluation of environmental persistence suggests that AP did not persist more than 12 hr in a hypothetically contaminated environment. Additionally, other detected potential pathogens such as Gallibacterium anatis and infectious bronchitis virus caused mild respiratory signs in the exposed birds. The HMTp210 and HagA genes of four IC field strains were sequenced and compared with published sequences of HMTp210 and HagA. The HMTp210 phylogeny showed a marginally imperfect clustering of the sequences in genogroups A, B, and C. Although not definitive, this phylogeny provided evidence that the four field strains aligned with previously characterized serovar C strains. Moreover, the base pair homology of the four strains was 100% identical to serovar C reference strains (H-18 and Modesto). HagA phylogeny was unclear, but interestingly, the IC field strains were 100% homologous to C-1 strains reported from Mexico and Ecuador. Finally, vaccine protection studies in commercial hens indicate that clinical signs are induced by a combination of IC and other concomitant pathogens infecting commercial birds. Additionally, vaccine protection experiments performed in SPF hens indicated that protection provided by the two commercial vaccines tested provided a reduction in clinical signs and bacterial shedding after two applications.

A Comparative Study for Egg Production in Layers by Decision Tree Analysis

A Comparative Study for Egg Production in Layers by Decision Tree Analysis

The current epidemiological status of infectious coryza and efficacy of PoulShot Coryza in specific pathogen-free chickens.

Infectious coryza (IC) is an infectious disease caused by Avibacterium (Av.) paragallinarum. IC is known to cause economic losses in the poultry industry via decreased egg production in layers. Between 2012 and 2013, Av. paragallinarum was isolated from seven chicken farms by Chungbuk National University. We identified Av. paragallinarum, the causative pathogen of IC by polymerase chain reaction (PCR) and serovar serotype A, by multiplex PCR. Antibiotic sensitivity tests indicated that a few field-isolated strains showed susceptibility to erythromycin, gentamicin, lincomycin, neomycin, oxytetracycline, spectinomycin, and tylosin. A serological survey was conducted to evaluate the number of flocks that were positive for Av. paragallinarum by utilizing a HI test to determine the existence of serovar A. Serological surveys revealed high positivity rates of 86.4% in 2009, 78.9% in 2010, 70.0% in 2011, and 69.6% in 2012. We also challenged specific pathogen-free chickens with isolated domestic strains, ADL121286 and ADL121500, according to the measured efficacy of the commercial IC vaccine, PoulShot Coryza. We confirmed the effectiveness of the vaccine based on relief of clinical signs and a decreased re-isolation rate of ADL121500 strain. Our results indicate IC is currently prevalent in Korea, and that the commercial vaccine is effective at protecting against field strains.

Impact of lighting on poultry reproduction and recent advances.

Abstract Different wavelengths of visible light spectrum influence the reproductive system of domestic avian species. Light perceived by the retina is involved in growth and behaviour whereas light perceived by the hypothalamus is involved in reproduction through photosensitive cells in the brain (extra-retinal photoreceptors) and it varies with intensity of different wavelengths of light. Red spectrum of light with 675 nm of wavelengths is more gonadostimulatory than shorter wavelengths of 450-475 nm of light. Recent studies indicate that the hypothalamic opsins are involved in avian photoreception. Non-mammalian vertebrates detect light by deep brain photoreceptors that lie outside the retina and pineal gland to regulate seasonal cycle of reproduction. It was reported that opsin is a deep-brain photoreceptive molecule in the avian brain that regulate seasonal reproduction in birds. Lighting recommendations should be based on local environmental conditions, house type, light requirements for pullets, growers, broilers, layers and overall stockman objectives. Lighting programmes that are inappropriately employed may impair average daily gain and compromise flock performance. Careful observations of flock performance, nutrient density and intake are also important in designing lighting programmes in broilers. Layer and broiler lighting programmes in concert with the proper genetics, environment, nutrition and management create the best in welfare for the animal and performance for the integrator. Light-emitting diode (LED) lighting in poultry facilities is cost effective and could increase egg production in layers and early body weight gain in broilers exposed to red and green LED light, respectively.

Effect of Different Levels of Nanoparticles Chromium Picolinate Supplementation on Performance, Egg Quality, Mineral Retention, and Tissues Minerals Accumulation in Layer Chickens

This study was conducted to investigate the effects of various levels of nanoparticles chromium picolinate on performance, egg quality, minerals retention, and tissues accumulation of layer chickens. This study used 54 seventy-week old post-molt laying hens randomly allocated into 0 (control), 500 ppb (µg kg-1) Cr and 3000 ppb Cr groups for a 60-day experiment. The chromium was nanosize (80.8 ± 2.7 nm) chromium picolinate (NanoCrPic) and each treatment was undertaken with six replicates. In the meantime, a total of 18 birds (1 bird/replicate) were used for metabolic experimentation. The results of the experiment indicated that there were no significant effects on body weight, feed intake, feed efficiency, and egg production of layers. Supplemental NanoCrPic could significantly (p < 0.05) improve egg quality, or retention of chromium and zinc, but decrease shell ratio in the 60th day eggs. The addition of NanoCrPic resulted in increased minerals accumulation in tissues such as Cr, Ca, and P concentration in the liver, Cr concentration in the yolk and Ca concentration in the eggshell. In conclusion, supplemental NanoCrPic improved Cr and Ca accumulation in the liver and egg, improved Zn and Mn retention in layer chickens.

Vaccination against histomonosis prevents a drop in egg production in layers following challenge

The effect of attenuated Histomonas meleagridis on pullets was investigated and the protection of vaccinated adult laying hens against a severe challenge was studied in the same experimental setting. Four groups of 25 pullets were set up at 18 weeks of life and birds in two groups were vaccinated with in vitro-attenuated H. meleagridis. Chickens in two groups (vaccinated and non-vaccinated) were challenged 5 weeks later with virulent histomonads, while the remaining groups were retained until termination of the study 11 weeks post vaccination. Vaccination of pullets did not have any impact on their subsequent performance. Egg production of non-vaccinated but challenged birds dropped significantly (P≤0.05) between 2 and 4 weeks post challenge (p.c.) to 58.7%, compared with 90% in control chickens. At 4 weeks p.c., the drop in egg production in vaccinated and challenged birds was significantly lower (P=0.02) than in non-protected layers. Pathological changes were found only in challenged birds 2 and 6 weeks p.c. Several non-vaccinated birds showed severe lesions in the caeca with sporadic involvement of the liver and atrophy of the reproductive tract. Vaccination prior to challenge reduced the incidence of pathological findings. For the first time, vaccination of pullets with in vitro-attenuated histomonads could be shown to be an effective and safe prophylactic tool to prevent a severe drop in egg production of commercial layers following experimental infection.

Informal Nutrition Symposium Biological limits to productivity

SUMMARY There will obviously be biological limits to productivity in terms of growth rate of meat birds and egg production in layers and breeding stock. We continue to see an unprecedented increase in commercial performance, and to date, we have managed to accommodate this everincreasing potential as provided by the poultry geneticists. In many situations, we do not see the full genetic potential at the poultry farm because of myriad factors that negatively affect productivity compared with maintaining these birds under small-scale experimental conditions. Under such ideal conditions, we have realized 345 eggs in 365 d in some strains of white-egg layers, whereas handling individual broilers during trials has resulted in weights of almost 4 kg at 42 d. These values therefore represent the true genetic potential of these birds and suggest that we are nowhere near the biological limit to productivity in commercial flocks of layers, broilers, or turkeys. It is not the intent of this review to discuss the reasons for “reduced” commercial productivity; rather, the goal is to discuss potential factors that may influence the absolute biological limits to performance inherent today and, more important, in the future.