Transcriptome Analysis of Long Noncoding RNAs and mRNAs in Granulosa Cells of Jinghai Yellow Chickens Illuminated With Red Light

Jinghai Yellow chickens are a new indigenous breed with a dual purpose in China, but their egg laying performance is limited. Compared with white light (WL), exposure to red light (RL) can improve the egg laying performance of hens. Herein, to elucidate the molecular mechanism by which RL affects the egg laying performance, RNA sequencing was used to analyze long noncoding RNAs (lncRNAs) and mRNAs from granulosa cells of small yellow follicles from Jinghai Yellow chickens in RL and WL groups. A total of 12,466 lncRNAs were identified among the assembled transcripts, of which 168 lncRNAs were significantly different between the RL and WL groups (101 downregulated and 67 upregulated). Additionally, 1182 differentially expressed mRNAs were identified (958 downregulated and 224 upregulated). Integrated network analysis demonstrated that numerous differential mRNAs were involved in follicular development through steroid hormone synthesis, oocyte meiosis, and the PI3K-Akt signaling pathway. The impact of lncRNAs on cis and trans target mRNAs indicates that some lncRNAs play important roles in follicular development of small yellow follicles. The results provide a starting point for studies aimed at understanding the molecular mechanisms by which monochromatic light affects follicular development and egg production in hens.

The Effects of UV-A Light Provided in Addition to Standard Lighting on Plumage Condition in Laying Hens

Natural light with ultraviolet spectrum (UV) influences the birds´ perception, the reflectivity of their plumage and affects bird behavior. Therefore, in Germany, laying hens kept in barns should be provided with daylight inlets. Nevertheless, lighting in laying hen houses with a UV proportion is not common practice and little is known about the detailed effects of UV-A lighting during the entire rearing and production period. The present on-farm study examines the impact of light quality on plumage loss, skin injuries and production parameters of laying hens. Therefore, about 92,000 Lohmann Brown hens with untrimmed beaks were kept on a farm in two different groups. Half of them were housed in a barn containing 10 pens illuminated by additional UV-A light (simulate "daylight spectrum"). The other half in the second barn were equally grouped, but exposed to standard lighting for poultry houses. Health, production parameters and plumage condition were monitored during rearing and production. The study results reveal that additional UV-A light is associated with the occurrence of plumage damage and cannibalistic injuries during production. In all groups, the plumage condition of the hens was intact when the hens started laying and declined with age. Therefore, complex interactions alongside UV illumination, environmental enrichment, feed and feeding strategies as well as other management factors that possibly affected both feather damage and skin injuries must also be taken into account.

Effect of fluorescent vs. poultry-specific light-emitting diode lights on production performance and egg quality of W-36 laying hens

More energy-efficient, durable, affordable, and dimmable light-emitting diode (LED) lights are finding applications in poultry production. However, data are lacking on controlled comparative studies concerning the impact of such lights during the pullet rearing and subsequent laying phase. This study evaluated two types of poultry-specific LED light (PS-LED) vs. fluorescent light (FL) with regards to their effects on hen laying performance. A total of 432 Hy-Line W-36 laying hens were tested in two batches using four environmental chambers (nine cages per chamber and 6 birds per cage) from 17 to 41 weeks of age (WOA). Dim-to-red PS-LED and warm-white FL were used in the laying phase. The hens had been reared under a dim-to-blue PS-LED or a warm-white FL from 1 to 16 WOA. The measured performance variables included 1) timing of sexual maturity, 2) egg production performance, 3) egg quality, and 4) egg yolk cholesterol. Results showed that the two types of light used during the laying phase had comparable performance responses for all response parameters (P > 0.05) with a few exceptions. Specifically, eggs laid from hens in the PS-LED treatment had lower shell thickness (P = 0.01) and strength (P = 0.03) than those in the FL treatment at 41 WOA. The two types of light used during the rearing phase did not influence the 17 to 41 WOA laying performance, except that hens reared under the PS-LED laid eggs with lower shell thickness (P = 0.02) at 32 WOA as compared to hens reared under the FL. This study demonstrates that the emerging poultry-specific LED lights yield comparable production performance and egg quality of W-36 laying hens to the traditional fluorescent lights.

Effects of light-emitting diode light v. fluorescent light on growing performance, activity levels and well-being of non-beak-trimmed W-36 pullets

More energy-efficient, readily dimmable, long-lasting and more affordable light-emitting diode (LED) lights are increasingly finding applications in poultry production facilities. Despite anecdotal evidence about the benefits of such lighting on bird performance and behavior, concrete research data were lacking. In this study, a commercial poultry-specific LED light (dim-to-blue, controllable correlated color temperature (CCT) from 4500 to 5300 K) and a typical compact fluorescent light (CFL) (soft white, CCT=2700 K) were compared with regards to their effects on growing performance, activity levels, and feather and comb conditions of non-beak-trimmed W-36 pullets during a 14-week rearing period. A total of 1280-day-old pullets in two successive batches, 640 birds each, were used in the study. For each batch, pullets were randomly assigned to four identical litter-floor rooms equipped with perches, two rooms per light regimen, 160 birds per room. Body weight, BW uniformity (BWU), BW gain (BWG) and cumulative mortality rate (CMR) of the pullets were determined every 2 weeks from day-old to 14 weeks of age (WOA). Activity levels of the pullets at 5 to 14 WOA were delineated by movement index. Results revealed that pullets under the LED and CFL lights had comparable BW (1140±5 g v. 1135±5 g, P=0.41), BWU (90.8±1.0% v. 91.9±1.0%, P=0.48) and CMR (1.3±0.6% v. 2.7±0.6%, P=0.18) at 14 WOA despite some varying BWG during the rearing. Circadian activity levels of the pullets were higher under the LED light than under the CFL light, possibly resulting from differences in spectrum and/or perceived light intensity between the two lights. No feather damage or comb wound was apparent in either light regimen at the end of the rearing period. The results contribute to understanding the impact of emerging LED lights on pullets rearing which is a critical component of egg production.

Green Light During Rearing Does Not Significantly Affect the Performance of Egg-Type Pullets in the Laying Phase

Lohmann White pullets were reared in cages and illuminated with 8 h of white light at 2.6 lx or green light at 3.0 lx from commercial incandescent lamps. They were transferred to individual cages and the photo-period was increased to 14 h of white light at 15, 17, or 19 wk. Pullets grown under green light had significantly lighter BW at 6 wk than did birds grown under white light, but BW were similar at 12, 15, 17, and 19 wk. Although mean age at first egg was 1 d earlier for birds reared under white light, there were no significant differences between the 2 groups for any other performance trait. These findings do not support lamp manufacturers' claim that green fluorescent light during rearing improves performance. As expected, the birds photostimulated at 17 wk matured after the 15-wk birds but before the 19-wk birds. Subsequently, the 15-wk birds laid more eggs to 71 wk, but had a lower mean egg weight and thinner shells (higher deformation) than the other 2 groups. Albumen height and feed intake were similar for all 3 photo-stimulation ages.

Broiler performance when reared under various light sources

Three trials were conducted to determine if modern energy-efficient light sources, which vary in wavelength emission, affect broiler growth performance. The effect of light source on growth performance was determined by measuring body weight, feed conversion, and livability at intervals throughout rearing and at market age in three flocks of approximately 3,600 broilers each. Illuminance within the light-proof experimental facility was approximately 5 1x and photoregimen was 1 h dark:23 h light. Trial 1 compared incandescent (IN), warm white fluorescent (WWF), and daylight fluorescent (DLF) light sources. The WWF source provided superior body weight compared to IN light but feed conversion ratios were similar. Both IN and WWF light sources resulted in better body weight and feed conversion than that of the DLF light source. Trial 2 used IN, WWF, DLF, PL-5 fluorescent (PLF), design white fluorescent (DWF), and high pressure sodium (HPS) light sources. The PLF source resulted in mean body weight significantly higher than those produced by IN, HPS, and DWF. No other significant differences were observed. Trial 3 used IN, WWF, DLF, PLF, HPS, and low pressure sodium (LPS) light sources. Feed conversion for the HPS treatment was superior to that of PLF and LPS treatments. No other significant differences were observed. Light source did not affect livability in any of the trials. These trials demonstrated that energy-efficient light sources varying in wavelength emission may affect broiler growth performance, but consistent differences were not observed. Generally, IN light sources may be replaced with more energy-efficient light sources without adverse effects on broiler growth performance.