A new method to manipulate broiler chicken growth and metabolism: Response to mixed LED light system

Impact of dichromatic lighted incubation on hatching result and post-hatch performance of broiler chickens

This study was planned to evaluate the impact of dichromatic lights during incubation on the hatching and post-hatch performance of broiler chickens. A total of 500 eggs of broiler breeder (Ross 308; Age 44 weeks) were evenly divided according to a completely randomized design into 4 treatments having 5 replicates and 25 eggs each. Treatments consisted of dichromatic lights Blue + Red (BR), Green + Red (GR) and Green + Blue (GB) provided at an intensity of 250 lx for 12 h a day along with a Dark (D) environment. After hatching 200 chicks (50 from each respective light group) were divided into 4 treatments with 5 replicates each having 10 chicks. Results indicated a higher embryo index (13.12%) in the GR group on the 12th day of incubation; while an ideal hatch window was observed in GR and GB (98.18% and 96.00% hatched chicks) lighting groups. In hatching traits, higher hatchability (86.15) and hatch of fertile (93.85) percentages were observed in GR lighting followed by GB, BR and Dark treatment groups; while dead-in shell embryos were lowest in the GR group. In growth performance, higher feed intake (513.20 g) and body weight (479.20 g) were observed in the GB group followed by GR, BR and dark group; and feed conversion ratio (FCR) was better in the GR group (1.06). In welfare parameters, improved physical asymmetry (0.90 mm) and tonic immobility (54.40 s) were measured in the GR group followed by GB, BR and the dark group. It was concluded that under experimental conditions when broiler breeder eggs are provided with GR lighting during incubation, it can help to improve hatchability, growth performance and welfare traits in chicks.

Effect of housing system on carcass composition, meat quality, digestive morphometry, and leg bone dimensions of Ross 308 parent broilers

The aim of the present study was to compare the effects of 2 Ross 308 parent broiler housing systems (SLS-slat-litter system vs. LS-litter-based system) in terms of carcass composition, meat quality traits (chemical composition, texture, physicochemical properties), as well as biometric traits of the digestive system and leg bones. The weight of the eviscerated carcass and the proportion of carcass components were determined at the end of the reproductive period (60 wk of life) following slaughter. The lengths and diameters of the individual intestinal segments, the weight of selected internal organs, the acidity (pH24) and electrical conductivity (EC24), as well as the color (L*, a*, b*) of breast and thigh muscles were assessed. The basal chemical composition of the breast and thigh muscles was also determined, texture analysis of the pectoralis major muscle and measurements of the femur and tibia of parent broilers were also carried out. The housing system differentiated the birds in terms of percentage of breast muscle (SLS-27.4% vs. LS-26.0%) and intramuscular fat content in the breast muscle (SLS-1.1% vs. LS-0.7%), spleen weight pH of the breast and thigh muscles and EC of the thigh muscles (SLS-9.3 mS/cm vs. LS-7.0 mS/cm). Differences were also found between the study groups in the color of the breast and thigh muscles. The housing system affected the results of the texture analysis of the pectoralis major muscle. The birds differed significantly (P < 0.05) in terms of gumminess (SLS-11.1 N vs. LS-16.0 N), springiness, chewiness (SLS-17.6 N × cm vs. LS-23.4 N × cm) and cohesiveness parameters. The housing system did not affect the lengths and diameters of the individual intestinal segments, except for the length of the terminal intestine. There was no significant effect of the housing system on the tibia and femur dimensions analyzed. This study provided information about differences in certain carcass characteristics, meat quality, and the digestive system of Ross 308 parent broilers in relation to the maintenance system.

The Behavioral and Productive Characteristics of Japanese Quails (Coturnix japonica) Exposed to Different Monochromatic Lighting

The purpose of this study is to examine the impact of monochromatic illuminations at wavelengths of white (400-700 nm), green (560 nm), yellow (580 nm), blue (480 nm), and red (660 nm) on the performance and behavioral traits of Japanese quails throughout their fattening period. A total of 300 quails in five lighting experimental groups were housed in their conventional rearing cages. Weekly live weights of quails were measured individually, developmental stability was determined, and behavior and fear tests were performed. The body weight averages of quails exposed to blue, green, and yellow light were determined to be greater than those exposed to white and red light (p < 0.05). In terms of the mature weight parameter and the weight of the inflection point of the Gompertz growth model, the averages of the quails exposed to green and blue monochromatic lighting were higher (p < 0.05). The most negative findings on aggressive behavior were observed in birds exposed to monochromatic yellow and red light. Although the body weight of quails exposed to yellow monochromatic lighting was similar to that of quails exposed to green and blue monochromatic lighting, green and blue monochromatic lighting produced the best results in terms of growth, behavior, and developmental stability characteristics. Consequently, it is believed that consistently using green or blue monochromatic lighting programs when raising Japanese quails may provide economic advantages to the producers.

The signal pathway of melatonin mediates the monochromatic light-induced T-lymphocyte apoptosis in chicken thymus

Our previous study revealed that under monochromatic red light (RL), the melatonin nuclear receptor reduces the proliferation activity of broiler thymic lymphocytes through the P65 signaling pathway. The main objective of this study was to investigate the signal mechanism by which RL decreases thymic lymphocyte proliferation. Initially, broilers were purchased and randomly assigned to be fed under white light (WL), red light (RL), green light (GL), and blue light (BL). Pinealectomy was performed 3 d later, and the broilers were euthanized after 14 d. The results showed that the expression of the antiapoptotic proteins Bcl-2/Bcl-xl decreased under RL, while the expression of the pro-apoptotic factor Bax/caspase-3 and the pro-inflammatory factors INF-γ/TNF-α/IL-6 increased. After pinealectomy, the expression of Bax/TNF-α/IL-6 increased in conjunction with the decrease in Bcl-2 expression. In vitro experiments demonstrated that exogenous melatonin decreased the expression of Bax/TNF-α/IL-6 in thymic lymphocytes of chicks reared under RL. This melatonin-induced effect was enhanced by SR1078 (RORα/RORγ agonist) but attenuated by SR3335 (RORα antagonist) and BAY (P65 antagonist). These findings revealed that the melatonin nuclear receptor RORα/RORγ promotes the expression of the pro-apoptotic factor Bax/caspase-3 and the pro-inflammatory factors INF-γ/TNF-α/IL-6, while inhibiting the expression of the antiapoptotic factor Bcl-2/Bcl-xl. Our research suggested the signaling pathway of monochromatic red light impacts the apoptosis of thymus lymphocytes in broiler.

Effect of vaccination program on immune response, production performance, and carcass composition of Ross 308 broiler chickens

The aim of this study was to compare the effect of 2 different vaccination programs using vaccines against infection bronchitis virus (IBV) and avian metapneumovirus (aMPV) on the humoral immune response, production performance, carcass weight and composition, and the percentage of selected internal organs. During the rearing of broiler chickens, blood was collected for serum samples from randomly selected birds from each experimental group on d 1, 21, 28, and 38. Geometric mean titer (GMT) values were determined for the aforementioned diseases using serological ELISA tests, performed during routine veterinary inspections. During rearing, body weight, mortality, and feed consumption were monitored, allowing the calculation of feed consumption per kilogram of body weight gain (FCR) and the European Production Index (EPI). At the end of rearing, 20 chickens were selected for dissection, 10 birds from each group. After slaughter, the weight of the eviscerated carcass was determined, and the percentages of carcass parts and selected internal organs in the body weight were calculated. The vaccination program exerted a significant (P<0.05) effect on body weight on days 14, 21, 28, 35 and 42, the percentage of wings in the carcass and the proportion (%) of heart, liver and spleen in body weight. ELISA showed no significant effect of the vaccination program on the anti-IBV serological response, and no negative effect of covaccination against both diseases on the anti-aMPV serological response.

Influence of Different Light Spectra on Melatonin Synthesis by the Pineal Gland and Influence on the Immune System in Chickens

It is well known that the pineal gland in birds influences behavioural and physiological functions, including those of the immune system. The purpose of this research is to examine the endocrine-immune correlations between melatonin and immune system activity. Through a description of the immune-pineal axis, we formulated the objective to determine and describe: the development of the pineal gland; how light influences secretory activity; and how melatonin influences the activity of primary and secondary lymphoid organs. The pineal gland has the ability to turn light information into an endocrine signal suitable for the immune system via the membrane receptors Mel1a, Mel1b, and Mel1c, as well as the nuclear receptors RORα, RORβ, and RORγ. We can state the following findings: green monochromatic light (560 nm) increased serum melatonin levels and promoted a stronger humoral and cellular immune response by proliferating B and T lymphocytes; the combination of green and blue monochromatic light (560-480 nm) ameliorated the inflammatory response and protected lymphoid organs from oxidative stress; and red monochromatic light (660 nm) maintained the inflammatory response and promoted the growth of pathogenic bacteria. Melatonin can be considered a potent antioxidant and immunomodulator and is a critical element in the coordination between external light stimulation and the body's internal response.

Influence of Light Supplement on Duck Sternal Calcification from Integrated Analysis of Metabolome and Transcriptome

Calcification of bones is the critical process of bone development in birds, which is very important for sustaining the normal biological function of bones. Light is one of the vital factors affecting bone development, but whether light intensity affects bone calcification and the underlying mechanism is still unknown. In this study, we used duck sternum as a model to analyze the calcification process under different light regimes. In addition, the underlying mechanism was also illustrated by integrating metabolomics and transcriptome methods.

The experiment lasted from 14 to 51 d of duck age. The control group (LP1) kept light intensity 2 lx during the whole experiment. The two light supplement groups (LP2, LP3) were given light with the intensity of 70 lx at different time (14–29 d for LP2, 14–43 d for LP3). Samples were collected at 52 d of duck age. Sternal calcification analysis showed no significant difference in proportion of area of cartilage matrix and trabecular bone in keel tissue among the 3 groups, but the degree of keel calcification in LP3 was higher than in the other 2 groups. Serum metabolomics showed 32 and 28 differentially accumulated metabolites (DAMs) in the 2 comparison groups, LP1 vs. LP3 and LP1 vs. LP2, respectively. Carboxylic acids and derivatives were the most abundant among the DAMs. Sternal transcriptome analysis showed 231 differentially expressed genes (DEGs), including 177 upregulated genes and 54 downregulated genes in group LP1 vs. LP3, and 22 DEGs in group LP1 vs. LP2. Protein-protein interaction (PPI) network analysis on DEGs between LP1 and LP3 showed that genes BTRC, GLI1, BMP4, and FOS were in the core position of the interaction network, and are also involved in bone development. KEGG pathway analysis of DAMs and DEGs showed that differences in Hedgehog signaling pathway, MAPK signaling pathway, apoptosis, energy metabolism, and amino acid metabolism following light treatment seem likely to have contributed to the observed difference in calcification of duck sternum.

Light regimen on health and growth of broilers: an update review

The importance of lighting regimen is increasing with the industrialization of poultry production, as lighting has been intimately associated with not only the establishment of rhythm and synchronous physiology of broiler chickens, but also the secretion of hormones associated with broiler maturation and growth. In recent years, increasing attention has been paid to the effects of lighting management on growth performance, immune status, and welfare of broilers. An appropriate lighting regimen, including proper source of lighting, intensity, duration, and wavelength (color) of light, is crucial to improve the growth performance and welfare of broilers. In this review, we updated the impacts of different light regimens on health and growth performance of broilers.

Evaluation of Chemical Composition and Meat Quality of Breast Muscle in Broilers Reared under Light-Emitting Diode

Simple Summary

The present study was designed to investigate the role of three different light-emitting diode (LED) light color temperatures (Neutral, Cool, and Warm) on the growth performance, carcass characteristics, and breast meat quality of broilers. No significant differences were observed in carcass yield in any of the experimental conditions. The changes observed in physical and chemical properties of breast meat samples suggest that LED light was not able to modify the quality of the products; therefore, it could represent a good alternative technology to traditional light sources.

Abstract

The present study was designed to investigate the role of three different light-emitting diode (LED) light color temperatures on the growth performance, carcass characteristics, and breast meat quality of broilers. In our experimental condition, 180 chicks were randomly distributed into four environmentally controlled rooms (three replicates/treatment). The experimental design consisted of four light sources: neon (Control), Neutral (Neutral LED; K = 3500–3700), Cool (Cool LED; K = 5500–6000), and Warm (Warm LED; K = 3000–2500). Upon reaching the commercial weight (3.30 ± 0.20 kg live weight), 30 birds from each group were randomly selected, and live and carcass weight were evaluated to determinate the carcass yield. Following the slaughtering, samples of hemibreast meat were collected from each group and analyzed for physical and chemical properties, fatty acids composition, and volatile compounds. Live weight and carcass weight were negatively influenced by the Warm LED; however, no significant differences were observed in carcass yield in any of the experimental conditions. Higher drip loss values were detected in breast meat samples obtained by broilers reared under Neutral and Cool LEDs. In regard to the meat fatty acids profiles, higher polyunsaturated fatty acids (PUFA) values were detected with the Warm LED; however, the ratio of PUFA/saturated fatty acids (SFA) did not change in any group. The evaluation of volatile profiles in cooked chicken meat led to the identification of 18 compounds belonging to the family of aldehydes, alcohols, ketones, and phenolic compounds, both at 0 (T0) and 7 (T7) d after the cooking. The results of the present study suggest that the LED represents an alternative technology that is cheaper and more sustainable than traditional light sources, since it allows economic savings for poultry farming without significant alterations on the production parameters or the quality of the product.

Stress and immunity in poultry: light management and nanotechnology as effective immune enhancers to fight stress

The poultry industry plays a significant role in boosting the economy of several countries, particularly developing countries, and acts as a good, cheap, and affordable source of animal protein. A stress-free environment is the main target in poultry production. There are several stressors, such as cold stress, heat stress, high stocking density, and diseases that can affect birds and cause several deleterious changes. Stress reduces feed intake and growth, as well as impairs immune response and function, resulting in high disease susceptibility. These effects are correlated with higher corticosteroid levels that modulate several immune pathways such as cytokine-cytokine receptor interaction and Toll-like receptor signaling along with induction of excessive production of reactive oxygen species (ROS) and thus oxidative stress. Several approaches have been considered to boost bird immunity to overcome stress-associated effects. Of these, dietary supplementation of certain nutrients and management modifications, such as light management, are commonly considered. Dietary supplementations improve bird immunity by improving the development of lymphoid tissues and triggering beneficial immune modulators and responses. Since nano-minerals have higher bioavailability compared to inorganic or organic forms, they are highly recommended to be included in the bird's diet during stress. Additionally, light management is considered a cheap and safe approach to control stress. Changing light from continuous to intermittent and using monochromatic light instead of the normal light improve bird performance and health. Such changes in light management are associated with a reduction of ROS production and increased antioxidant production. In this review, we discuss the impact of stress on the immune system of birds and the transcriptome of oxidative stress and immune-related genes, in addition, how nano-minerals supplementations and light system modulate or mitigate stress-associated effects.

Metabolism of Melatonin Synthesis-Related Indoles in the Turkey Pineal Organ and Its Modification by Monochromatic Light

The metabolism of pineal indoles is closely related to alterations in the light and dark phases of a daily cycle. Recent research showed important interspecies differences in the pineal biochemistry, and a strong impact of monochromatic light on many physiological processes in birds. Therefore, the aims of study were to characterize the metabolism of melatonin-synthesis indoles in the pineal organ of the domestic turkey, and to determine the changes occurring in this metabolism under the influence of different wavelengths and intensities of light. For this purpose, 3-week-old turkeys were kept under 16 lx white light, or under blue, green, and red light with intensities of 16, 32, and 64 lx during the photophase, and after 7 d were sacrificed at 4 h intervals. The activities of melatonin-synthesizing enzymes and the contents of indoles were measured in the same pineal organ. The results revealed that the activities of tryptophan hydroxylase and arylalkylamine N-acetyltransferase, and the levels of all tryptophan derivatives had significant daily changes in birds kept under each light condition used. The profile of pineal indole metabolism in 4-week-old turkeys was characterized by high-amplitude rhythms in the activity of arylalkylamine N-acetyltransferase and the contents of N-acetylserotonin and melatonin, equal relative amounts of serotonin and 5-hydroxyindoleacetic acid, and higher content of melatonin than N-acetylserotonin. The monochromatic light significantly modified the pineal indole metabolism, and its effects were dependent on the color and intensity of light. Pronounced changes occurred in the level of serotonin synthesis and the daily rhythm course of melatonin synthesis.

Effect of various monochromatic light-emitting diode colours on the behaviour and welfare of broiler chickens

This study was conducted to evaluate the effect of different monochromatic light-emitting diode colours on the behaviour and welfare of broiler chicks. A total of 750 one-day-old chicks were used and lighting was set up as follows: pure blue (PB, 440–450 nm), bright blue (460–470 nm), sky blue (480–490 nm), greenish blue (500–510 nm), and green (530–540), while fluorescent white (400–700 nm) was used as a control. Birds were placed into 30 independent light proof pens and each light treatment was replicated five times with 25 birds in each pen. Video was recorded and behaviour was evaluated twice per day and observed five consecutive days in a week. Broiler welfare was evaluated using the characteristics of gait score, tibia dyschondroplasia, tonic immobility duration, and heterophil:lymphocyte ratio. In results, sitting, walking, and ground pecking behaviour were influenced by the light colour from 0 to 7 d. Extending the rearing period from 8 to 21 d resulted in increased sitting behaviour and decreased walking and pecking behaviour in chicks in the PB treatment (P < 0.05). When the growth period was extended further (22–42 d), sitting behaviour increased when chicks were exposed to PB light (P < 0.05). The effect of light colour did not significantly influence welfare of broiler chicks. Thus, the present results suggest that PB light colour decreased broiler chickens movement and thus increased duration of sitting behaviour. These results would be helpful to choose light colour for broiler producers.

Exposure to Artificial Light at Night and the Consequences for Flora, Fauna, and Ecosystems

The present review draws together wide-ranging studies performed over the last decades that catalogue the effects of artificial-light-at-night (ALAN) upon living species and their environment. We provide an overview of the tremendous variety of light-detection strategies which have evolved in living organisms - unicellular, plants and animals, covering chloroplasts (plants), and the plethora of ocular and extra-ocular organs (animals). We describe the visual pigments which permit photo-detection, paying attention to their spectral characteristics, which extend from the ultraviolet into infrared. We discuss how organisms use light information in a way crucial for their development, growth and survival: phototropism, phototaxis, photoperiodism, and synchronization of circadian clocks. These aspects are treated in depth, as their perturbation underlies much of the disruptive effects of ALAN. The review goes into detail on circadian networks in living organisms, since these fundamental features are of critical importance in regulating the interface between environment and body. Especially, hormonal synthesis and secretion are often under circadian and circannual control, hence perturbation of the clock will lead to hormonal imbalance. The review addresses how the ubiquitous introduction of light-emitting diode technology may exacerbate, or in some cases reduce, the generalized ever-increasing light pollution. Numerous examples are given of how widespread exposure to ALAN is perturbing many aspects of plant and animal behaviour and survival: foraging, orientation, migration, seasonal reproduction, colonization and more. We examine the potential problems at the level of individual species and populations and extend the debate to the consequences for ecosystems. We stress, through a few examples, the synergistic harmful effects resulting from the impacts of ALAN combined with other anthropogenic pressures, which often impact the neuroendocrine loops in vertebrates. The article concludes by debating how these anthropogenic changes could be mitigated by more reasonable use of available technology - for example by restricting illumination to more essential areas and hours, directing lighting to avoid wasteful radiation and selecting spectral emissions, to reduce impact on circadian clocks. We end by discussing how society should take into account the potentially major consequences that ALAN has on the natural world and the repercussions for ongoing human health and welfare.

The effect of supplementary ultraviolet wavelengths on the performance of broiler chickens

Qualities of the light environment, such as the spectral composition of light, have been shown to impact growth and performance of broiler chickens. UVA light is visible to broiler chickens, whereas UVB wavelengths promote endogenous vitamin D synthesis, which could support their rapid development. The aim of the current study was to investigate the impacts of supplementary UVA and UVB wavelengths on performance indicators of broiler chickens. Day-old Ross 308 chicks (n = 638), reared to a target stocking density of 33 kg/m², were randomly assigned to 1 of 3 lighting treatments: A) White light emitting diode (LED) and supplementary UVA LED lighting (18-h photoperiod); B) White LED with supplementary UVA and UVB fluorescent lighting providing 30 μW/cm² UVB at bird level (lights on for 8 h of the total photoperiod to avoid overexposure of UVB); and C) White LED control group, representative of farm conditions (18-h photoperiod). Mortality was recorded, and broiler chickens were individually weighed at 8, 15, 22, 27, and 34 D of age. Generalized linear models and nonlinear mixed effects models (Gompertz curve) were fitted to determine the effects of UV wavelengths on broiler mortality and growth performance. UV did not impact breast or leg weight of broiler chickens but was associated with differences in mortality, growth, and end weight. Broiler chickens provided with UVA for the full 18-h photoperiod had slower initial growth than control broilers and a reduction in mortality. Results from male broilers reared with supplementary UVA + UVB for 8 h indicated they could reach finishing weights sooner than controls, which supports the potential for UVA + B to improve the growth performance of males. Results suggest that the provision of supplementary UVA + UVB wavelengths may improve the performance of male broiler chickens. The reduction in mortality in the UVA only treatment may warrant further investigation. The inclusion of UV wavelengths within poultry lighting regimes represents a promising area of further study.

Melatonin mediates monochromatic light-induced proliferation of T/B lymphocytes in the spleen via the membrane receptor or nuclear receptor

Our studies found that melatonin mediates the monochromatic light–induced lymphocyte proliferation in chickens. However, melatonin receptor subtypes contain membrane receptor (Mel1a/Mel1b/Mel1c) and nuclear receptor (Retinoic acid receptor–related orphan receptor [ROR] α/RORβ/RORγ) and are characteristic with cell specificity. This study compared receptor pathway of melatonin, which mediated the monochromatic light–induced T/B lymphocyte proliferations in chickens. Newly hatched chicks were randomly divided into white light, red light, green light (GL), and blue light groups. Green light promoted the membrane receptor expression in the spleen but decreased the nuclear receptor level compared with that of red light. These changes were accompanied by increase of T/B lymphocyte proliferation and plasma melatonin level under GL. Pinealectomy reversed aforementioned changes and resulted in no differences among the light-treated groups. Supplementation of exogenous melatonin enhanced GL-induced T/B lymphocyte proliferation in the spleen but was reversed by Mel1c antagonist prazosin and RORα agonist SR1078 and enhanced by RORα antagonist SR3335. However, Mel1b antagonist 4P-PDOT and RORγ antagonist GSK increased the stimulation effect of melatonin on GL-induced T lymphocyte proliferation but no effect on the B-lymphocyte proliferation. These results indicate that melatonin promotes the GL-induced T lymphocyte proliferation through Mel1b, Mel1c, and RORα/RORγ; however, the Mel1a, Mel1c, and RORα may be involved in the B lymphocyte proliferation.

Effect of dietary probiotics and prebiotics on the performance of broiler chickens

The prolonged use of antibiotics has led to the development of resistant bacteria and also led to accumulation of antibiotic residue in the poultry feed, this ultimately led to the prohibition of antibiotics as growth enhancers in animal production. Thus, there was a dire need for alternate sources to help in poultry production. Recently, probiotics and prebiotics claimed to be effective alternatives to antibiotics in the poultry. The objective of this study is to investigate the effect of different probiotics and prebiotics on the performance of broilers. The study involved 2 broiler cycles, 1 during winter and 1 during summer with a total of 425 1-day-old Cobb 500 broiler chicks for each cycle. They were allotted to 5 experimental treatments. The probiotics were Bacillus coagulans (1 g/kg dried culture) and Lactobacillus (1 g/kg dried culture of 12 commercial strains). The prebiotics included fructo-oligosaccharides (FOS) (5 g/kg) and mannan-oligosaccharide (MOS) derived from Saccharomyces cerevisiae (5 g/kg). The results showed that there was no effect of the different probiotics and prebiotics on the production performance of broilers. There was increased weight of the thymus in the control group. In cycle 1, the panelists indicated that the smell, color, taste, and texture of the cooked meat were acceptable, and that there were no significant differences between the different groups. There was no significant effect of the different diets on the biochemical parameters of the blood among the experimental groups at 3- and 5-wk of age. Phytohaemaglutinin test showed that dietary FOS and MOS induced higher cellular response than the other treatments (P = 0.04) in the first cycle. In the second cycle, the results revealed that dietary FOS induced higher cellular response than the other treatments (P = 0.019). The used experimental treatments have a positive effect on microbial count in 5-week-old broilers. There was no Salmonella sp. recorded using the experimental treatments in the first cycle, and the growth of E. coli was reduced significantly. In the second cycle, all treatments in 3-week-old broilers did not affect the count of both lactic acid bacteria (LAB) and E. coli. At 5-week-old of the same cycle, the bacterial count of E. coli increased even with control, whereas Salmonella growth was inhibited. The pH value was driven toward acidity in all of the treatments. Probiotics and prebiotics can be used in chicken feed safely and without any adverse effects on the productive parameters and immune status of the flock.

Effects of LED Light Color and Intensity on Feather Pecking and Fear Responses of Layer Breeders in Natural Mating Colony Cages

Simple Summary

Commercial breeder farms are moving forward using colony cages due to high efficiency, low energy input, clean production, and as a result of the rising public concerns with respect to the welfare of hens in conventional cages. Compared with conventional cages, layer breeders in colony cage are the parent-stock of laying hens and are confined together with roosters. However, the use of colony cages is still in a preliminary stage due to behavioral issues such as feather pecking (FP) and cannibalism. These behaviors can cause poor health, poor welfare, and economic problems. It is necessary to identify effective and proximal management practices to alleviate the damage that is caused by FP and cannibalism in such colony cage systems. This study aims to mitigate the problems of FP and cannibalism by utilizing light environment regulation. Results of this study indicates that red light and low light intensity could effectively alleviate FP and cannibalism during the laying period. Such knowledge might help to understand FP behavior and stress susceptibility of hens in this system and will provide a basis for the optimization of the cage equipment and the regulation of light environment.

Abstract

Natural mating colony cages for layer breeders have become commonplace for layer breeders in China. However, feather pecking (FP) and cannibalism are prominent in this system. The objective of this study was to investigate the effects of four light-emitting diode (LED) light colors (white: WL, red: RL, yellow-orange: YO, blue-green: BG) with two light intensities for each color, on FP, plumage condition, cannibalism, fear, and stress. A total of 32 identical cages were used for the eight treatments (four replicates for each treatment). For both light intensities, hens in RL had a lowest frequency of severe FP, whereas hens in WL had the highest frequency of severe FP. Hens in RL and BG had better plumage conditions than in WL and YO. Compared with RL and BG treatments, hens treated with WL and YO had a significantly longer tonic immobility (TI) duration. Hens treated with RL had a higher concentration of 5-hydroxytryptamine (5-HT), a lower concentration of corticosterone (CORT), and a lower heterophil to lymphocyte ratio than WL and YO. Furthermore, RL could significantly reduce mortality from cannibalism. Overall, hens treated with RL and low light intensity showed a lower frequency of severe FP, less damaged plumage, were less fearful, had lower physiological indicators of stress, and had reduced mortality from cannibalism. Transforming the light color to red or dimming the light could be regarded as an effective method to reduce the risk of FP and alleviate the fear responses of layer breeders.

Impact of lighting color and duration on productive performance and Newcastle disease vaccination efficiency in broiler chickens

Background and Aim

Manipulating lighting colors and regimens is considered an effective mean for improving broiler productivity. The influence of red, blue, and white light-emitting diode (LED) was investigated using three different regimens of lighting and darkness; continuous 23 h light (L):1 h dark (D), continuous 18 h L:6 h D, and intermittent 16 h L:8 h D hours on the performance, carcass weight (CW), feed and water intake (WI), serum glucose (GLUCO), triglycerides (TG), and cholesterol (TC), intestinal bacterial load, growth and metabolic hormones, and efficiency of Newcastle disease (ND) vaccine.

Materials and Methods

A total of 252 1-day-old Ross broilers on deep litter were divided into nine groups. The 1^st, 4^th, and 7^th groups were exposed to continuous 23L:1D, the 2^nd, 5^th, and 8^th groups were exposed to continuous 18L:6D, and the 3^rd, 6^th, and 9^th groups were exposed to intermittent 16L:8D (4L:2D, 4 times) lighting regimen using red, blue, and white LED lights, respectively. A total of 1350 samples (225 sera, 225 swabs, and 900 organ samples) were collected.

Results

Blue LED group revealed a highly significant increase (p<0.01) in live body weight, body weight gain, performance index, CW, spleen, heart, and liver weights, and anti-ND antibody titer, as well as a highly significant decline (p<0.01) of feed intake, WI, GLUCO, TG, TC, growth hormone, insulin, tri-iodothyronine (T3), tetra-iodothyronine (T4), total bacterial count (TBC), and total Enterobacteriaceae count compared to red and white LED lights in all tested lighting regimens. Continuous 23L:1D and 18L:6D regimens were significantly (p<0.01) superior to intermittent 16L:8D in their influence on the performance, CW, biochemistry, hormonal profile, and bacterial load.

Conclusion

The blue LED light associated with continuous 18L:6D or 23L:1D h regimen is highly recommended in broiler houses for their enhancing the productive performance, growth, and immunity.

Artificial light and biological responses of broiler chickens: dose-response

Light intensity is an important aspect for broiler production. However, previous results do not provide a solid scientific basis for quantifying the response of broilers to light intensity. This study performed a meta-analysis to model the response of broilers to 0.1-200 lux of light intensity. Meta-analysis was used to integrate smaller studies and increase the statistical power over that of any single study and explore new hypotheses. The results indicated that light intensity <5 lux caused welfare concern (P < 0.05) and light intensity <1 lux induced productivity loss of broiler (P < 0.05), whereas greater level of light intensity >10 lux led to increased mortality (P < 0.01) and decreased uniformity (P < 0.05). Meta-regression showed that 30-200 lux light intensity was negatively related to BW (P = 0.047) and feed intake change (P = 0.054), whereas a quadratic relationship was observed between feed conversion ratio change and 50-180 lux light intensity (R2 = 0.95). In addition, the majority of carcass characteristics (abdominal fat weight and wing weight) and metabolic indicators (K+, Ca2+, and T3) were affected by light intensity >5 lux. To conclude, this meta-analysis based on published data quantitatively identified that 5 lux of light intensity during grow-out period should be the minimum level to maintain a well productivity and welfare of broiler chickens.

Modulatory Effect of Monochromatic Blue Light on Heat Stress Response in Commercial Broilers

In a novel approach, monochromatic blue light was used to investigate its modulatory effect on heat stress biomarkers in two commercial broiler strains (Ross 308 and Cobb 500). At 21 days old, birds were divided into four groups including one group housed in white light, a second group exposed to blue light, a 3rd group exposed to white light + heat stress, and a 4th group exposed to blue light + heat stress. Heat treatment at 33°C lasted for five h for four successive days. Exposure to blue light during heat stress reduced MDA concentration and enhanced SOD and CAT enzyme activities as well as modulated their gene expression. Blue light also reduced the degenerative changes that occurred in the liver tissue as a result of heat stress. It regulated, though variably, liver HSP70, HSP90, HSF1, and HSF3 gene expression among Ross and Cobb chickens. Moreover, the Cobb strain showed better performance than Ross manifested by a significant reduction of rectal temperature in the case of H + B. Furthermore, a significant linear relationship was found between the lowered rectal temperature and the expression of all HSP genes. Generally, the performance of both strains by most assessed parameters under heat stress is improved when using blue light.