Intermittent Light Treatments Research Articles

Impact Light Regimen and Melatonin on Growth Performance, Welfare and Physiological Parameters of Broiler Chickens

The study was conducted to evaluate the effects of lighting program and melatonin on growth performance, welfare, and some physiological characteristics of broilers. A completely randomized design involved 2 photoperiods (constant lighting 24 L:0 D). and intermittent lighting 4 L:2 D) periodically for group one and two respectively, the third group the birds were to continuous lighting 24 hours with the addition of the melatonin 20 mg/kg of diet. A total of 180 unsexed one-day-old ROSS 308 broiler chicks randomly divided into three treatments with three replicates (20 birds per replicate). The results showed a significant superiority in the body weight and weight Gain of the intermittent light treatments and the addition of melatonin compared to the control treatment for broilers at 21 days. No significant differences in growth performance for broilers at 38 days, and there were no significant differences in dressing percentage, relative weight of the internal organs, temperature of the bird’s body parts, biochemical characteristics, and hormones, except for the significant decrease in the level of ALT for birds treated with melatonin and when raising birds under a lighting program. Intermittently, there was an improvement in the level of antioxidants through a decrease in MDA. There was a significant improvement in the measures of welfare, as the incidence of inflammation of the hock burn and Footpad dermatitis decreased. Results above suggest that the raising broilers under intermittent lighting system and treatment with melatonin did not affect production performance, but it improved the status of antioxidants and welfare Indications for broilers.

The effect of light regime and time of slaughter in broiler on broiler performance, liver antioxidant status, and expression of genes related to peptide absorption in the jejunum and melatonin synthesis in the brain.

This study aimed to assess the effects of light regime and time of slaughter on primal cut and organ weights, peptide transporter 1 (PEPT1) gene expression in the jejunum, arylalkylamine N-acetyltransferase (AANAT) gene expression in the brain, and liver oxidant/antioxidant status in broilers aged 37 days. The experiment was conducted in a factorial completely randomized design, with two light regimes (intermittent light varying according to bird age and continuous light under an 18 h light/6 h dark photoperiod) and four times of slaughter (2:00, 8:00, 14:00 and 20:00 h). There was an interaction effect on PEPT1 and AANAT expression, lipid and protein oxidation and superoxide dismutase (SOD) activity. In both light regimes, PEPT1 expression responded cubically to slaughter time. In the continuous light group, PEPT1 expression was highest in birds slaughtered at 2:00 and 14:00 h, whereas, in the intermittent light treatment, expression was highest at 8:00 h. In the continuous light regime, AANAT expression had a cubic relationship with time of slaughter, with the greatest values recorded at 20:00 h. In the intermittent light regime, slaughter time showed a cubic effect on lipid oxidation, which was highest at 8:00 h. In the continuous light group, there was a cubic effect on nitrite concentration, lipid oxidation, protein oxidation, and SOD activity; nitrite levels, lipid oxidation, and protein oxidation were highest and SOD activity was lowest in birds slaughtered at 14:00 h. Time of slaughter influenced catalase activity, which responded cubically; catalase activity was lowest at 8:00 and 14:00 h. This study is the first to demonstrate that PEPT1 expression in the jejunum of broilers follows a diurnal rhythm and varies according to light regime. The results also suggest that mainly continuous lighting and slaughter at 14:00 h when the animals are possibly more active may be more stressful to broilers.

Consequences of Different Types of Littoral Zone Light Pollution on the Parental Care Behaviour of a Freshwater Teleost Fish

Ecological light pollution occurs when artificial lights disrupt the natural regimes of individual organisms or their ecosystems. Increasing development of shoreline habitats leads to increased light pollution (e.g., from cottages, docks, automobile traffic), which could impact the ecology of littoral zones of lakes and rivers. Smallmouth bass (Micropterus dolomieu) engage in sole paternal care, guarding their nest continually, day and night, to protect their developing offspring. Any alterations to their behaviour—either directly because of the response to light or indirectly due to changes in nest predator activity and associated response of the bass—could lead to increased energetic demands for fish that have a fixed energy budget and ultimately reduce reproductive success. To examine this issue, tri-axial accelerometer biologgers were externally attached to nesting smallmouth bass during the egg stage to determine whether light pollution (i.e., dock lights with low levels of continuous light and spotlights with high intensity irregular light simulating automobile traffic) altered behaviour of nesting males relative to control fish. Our study revealed that both types of light pollution increased overall bass activity level compared with the control group. The intermittent light treatment group had the highest activity and exhibited large fluctuations between night and day activity levels. Fish in the continual light treatment group displayed statistically higher activity than the control fish but showed limited fluctuations between day and night activity levels. Our results suggest that continuous or intermittent light sources, common in shoreline habitats that have been developed, have the potential to alter the behaviour and thus energy use of nest-guarding fish. This study contributes to the growing body of literature on the ecological consequences of light pollution in aquatic ecosystems.

The Effects of Photoperiod Programs on Broiler Chicken Performance and Immune Response

Understanding the role of photoperiod regimens in regulating broiler performance and the immune response is becoming highly important. The objectives of the current investigation are to analyze the effects of photoperiod regimens on humoral and cell-mediated immune response as well as production characteristics in broiler chicken. A total number of 300 one day old male broiler chicks were divided randomly into three equal groups. For 6 weeks, the first group received continuous light (23L:1D) and the second and Third group received non-intermittent restricted light (12L:12D) and intermittent light (2L:2D) respectively. Intermittent light regimen induced activation of both peripheral T and B lymphocyte proliferation and energized antibody production significantly compared to the other two regimens. Furthermore, in the nonintermittent restricted light group, plasma Corticosterone concentration and H/L ratio were significantly higher compared to continuous and intermittent light groups. In addition, intermittent light treatment caused elevation of total white blood cells (WBC) and plasma T concentration significantly compared to control. 3 Moreover, intermittent light regimen reduced mortality rate 3 times and improved body weight by 10% compared to control. On the other hand, non-intermittent restricted light regimen had no effect on mortality rate, and suppressed body weight by 10% compared to control. In general, both intermittent and nonintermittent restricted light regimen improved feed conversion significantly compared to continuous light regimen. Even though the intermittent and non-intermittent restricted light regimens have the same period of darkness, the intermittent light regimen would be more beneficial than non-intermittent restricted light program.

Effects of environmental lighting on early semen production and correlated hormonal responses in turkeys

Recent work at our institution on lighting turkey males for semen production and correlated changes in plasma luteinizing hormone (LH) and testosterone (T) are summarized in this paper. In sexually mature males, both LH and T are secreted in pulses, with a pulse of LH about 10 min prior to a pulse of T. Pulses of LH and T occurred about every 2 h and were equally distributed between the light (L) and dark (D) portions of a 14 h L:10 h D d. The pattern of secretion and overall concentrations of LH and T were not affected by intermittent photoperiod lighting (1 L:2 D, 8 x d) in comparison to continuous photoperiod lighting (14 L:10 D) lighting. Pulses of LH or T were not entrained by L or D with the intermittent or continuous lighting treatment. To study the interaction of age and lighting treatment, males were exposed to one of two lighting treatments: long-day photoperiods (16 L:8 D) d(-1) from 10 to 12 or 29 wk of age (WOA) (Treatment LDLD) or short-day photoperiods (6 L:18 D d(-1) from 10 or 12 to 29 WOA, then long-day photoperiods (Treatment SDLD). Males in the LDLD treatment attained puberty earlier (25 WOA) than those in the SDLD treatment. In the later treatment, most of the males attained puberty after 29 WOA. Both LH and T were low until 18 WOA in the LDLD males, then both increased to adult levels over the next 2 to 3 wk. In the SDLD males, LH and T were lower than in the LDLD males until 48 h after switching to long-day photoperiods, when both were transiently higher before declining to lower adult levels by 35 WOA. Secretory patterns of LH and T were estimated at 13, 23, and 35 WOA, under both lighting treatments. At 13 WOA, LH and T were secreted in pulses, but levels of both hormones were low and not different between lighting treatments, and none of the birds (0/4) in either treatment were producing semen. At 23 WOA, LH and T were secreted in robust pulses, with the LDLD males having higher concentrations of LH and T than the SDLD males. At 23 WOA, most of the males in the LDLD group (3/4) but none in the SDLD group (0/4) were producing semen. At 35 WOA, 6 wk after photostimulation of the SDLD group, all males (4/4) in both groups were producing semen, and LH and T were at adult levels. However, fewer pulses of T were noted for males in the SDLD treatment.

Intermittent lighting increases egg weight and facilitates early photostimulation of turkey breeder hens

A major limitation to reducing the age at photostimulation of turkey breeder hens has been small egg size, especially at the start of lay. The present study was designed to determine whether intermittent lighting (IL) could be used to photostimulate hens at an early age (26 wk) and enhance the typical small egg size at the start of lay. Control hens were photostimulated with standard [16 h light (L):8 h dark (D)] lighting at 26 or 30 wk of age. An additional group of hens was photostimulated with IL (2L:12D:2L:8D) from 26 to 32 wk of age and then switched to 16L:8D thereafter. Data were collected for BW, onset of lay, egg production, and egg weight to 54 wk of age. Although IL delayed onset of lay there was no adverse effect on rate of lay because numbers of eggs per hen in 24 wk of photostimulation (30 to 54 wk of age) were similar to that of controls. However, because hens in the IL treatment were photostimulated at 26 wk of age they produced about 10 more eggs per hen (P = 0.18) to 54 wk of age than control hens photostimulated at 30 wk of age. In addition, IL increased egg weight during the first 7 d of lay by about 5% as compared to those of controls also photostimulated at 26 wk of age. Interestingly, the increased egg weight in the IL treatment persisted to the end of lay, well after IL had been switched to 16L:8D. Thus, IL lighting facilitated successful early lighting of hens.

Effect of Intermittent Lighting on the Reproductive Performance of First-Year and Recycled Turkey Hens ,

In each of two trials, a 2-by-2 factorial arrangement of treatments was utilized to evaluate the reproductive performance of first-year and recycled turkey hens to intermittent lighting (IL) through an egg-laying period of 20 wk. The IL treatment provided 4 h of light per day given as 2 h light: 12 h dark:2 h light:8 h dark (2L:12D:2L:8D). This treatment group was compared to controls maintained on 16L:8D. Data were collected for BW, feed intake, feed efficiency, time to first egg, eggs per hen fertility, hatchability, egg weight, and poult weight.Consistent age effects included greater BW, egg weight, and poult weight from recycled hens compared to first-year hens as well as a delay in the onset of laying and a reduction in egg production by six eggs per hen in the recycled hens. Feed intake and feed efficiency were similar in both age groups. Intermittent lighting delayed the onset of laying but increased the rate of lay by eight eggs per hen. Late-season fertility, feed efficiency, and egg weight were significantly increased by the IL treatment. The conclusion was that, for turkey hens, intermittent lighting can effectively improve reproductive performance.

Intermittent Lighting Regimens for Laying Hens

In a trial conducted in 1984 and repeated in 1985, 192 point-of-lay pullets were assigned to normal (17 h light, 7 h dark) or intermittent (2 h light, 4 h dark, 8 h light, 10 h dark) lighting regimens from 21 wk of age. Lighting treatments were reassigned after 22 and 32 wk of age and the trial terminated after 42 (Trial 1) or 52 wk (Trial 2) of age.No significant crossover effects were noted in body weight, egg production, or egg size. Significant differences were observed for feed consumption in Trial 1; there was 9% lower consumption for intermittent light treatments in Trial 2 (P<.05). The difference in response was probably due to better environmental temperature control in Trial 2. Intermittent lighting reduced the computed electricity (lighting) costs by 41% and showed no production disadvantages when introduced to, nor removed from, laying birds at various ages.

Intermittent Light and Growth Performance of Male Turkeys From 2 to 22 Weeks of Age ,

Growth performance of tom turkeys under intermittent lighting was examined. Light treatments were given from 2 to 22 weeks of age and consisted of a control group maintained on 23L:1D and three intermittent lighting regimens: 1L:3D repeated 6 times daily, .25L:.75D repeated 24 times daily, and 3L:11D:3L:7D repeated daily. Body weight, feed consumption, feed conversion, mortality, and leg abnormalities were recorded.Body weights of control toms at 18 and 22 weeks of age were significantly smaller than those of each of the intermittent light treatment groups. Weight differences ranged from .7 to 1.3 kg. Body weights among the three intermittent light treatments were similar. Although feed conversions at all five measurement periods were numerically better in all of the intermittent light treatment groups than the control group, differences were not significantly different at and beyond 14 weeks of age. Likewise, no significant differences in mortality or leg disorders occurred among the light treatment groups during the study.The results of this study indicate that torn market turkeys can have a better growth performance, along with a savings in electricity used for lighting, when raised under intermittent lighting rather than under a single, continuous photoperiod of 23 hr/day.

The Effect of Intermittent Light Treatment on Growth of Broilers Grown Under Commercial Conditions

The effect of intermittent light treatment on rate of growth of broilers 3 to 7 weeks of age was investigated under commercial conditions. All chickens received continuous light from day-old to 3 weeks of age and then were exposed to one of the following: 1) continuous light; 2) 9L: 3D:9L: 3D; 3) 8L: 4D: 8L: 4D. Body weights were obtained.Broilers exposed to continuous light and then switched to intermittent light at 3 weeks of age were statistically heavier (P<.05) than those on continuous light when sampled at 4, 5, 6, and 7 weeks of age. In addition, intermittent light treatment saved up to 33% of the calculated electrical lighting cost used during the 3- to 7-week periods.

Effectiveness of Intermittent Light Treatments on Anthocyanin Synthesis in Dark-Grown and Light-Pretreated Seedlings

Differences in the extent of anthocyanin production between intermittent light treatments with short and long dark intervals between successive irradiations are more pronounced in dark-grown than in light-pretreated cabbage seedlings. This observation is consistent with the hypothesis, based on destruction kinetics data, that there might be two pools of phytochrome, a labile one and a stable one, present in different proportions in dark-grown and light-pretreated seedlings, and suggests that light-dependent changes of the stable to labile phytochrome ratio might be physiologically significant in the photoregulation of photomorphogenic responses.

Effect of Intermittent Lighting on Energy Savings and Semen Characteristics of Breeder Tom Turkeys

Large White breeder toms were exposed to one of the following light treatments at 34 weeks of age: 1) 15L:9D (control); 2) 2L:11D:4L:7D; 3) 4L:9D:4L:7D; 4) 2L:11D:2L:9D. After 4, 8, 12, and 18 weeks of exposure to these intermittent light treatments, body weight, feed consumption, and semen quality and quantity were determined. Although they maintain similar body weights, toms on intermittent light consumed less feed, produced equivalent semen volumes with similar sperm numbers, and maintained percent normal sperm more persistently during the summer heat than control toms. Compared to the 15L:9D controls, electrical savings for light as great as 73% was calculated for intermittent light. It was concluded that toms can be maintained more efficiently on intermittent lighting than a standard lighting program of 15 hr of light per day.

Calcium-induced formation of chlorophyll b and light-harvesting chlorophyll [formula omitted] complex in cucumber cotyledons in the dark

Dark-grown cucumber seedlings were exposed to intermittent light (2 min light and 98 min dark) and then cotyledons were incubated with 50 mM CaCl 2 in the dark. Chlorophyll (Chl) a was selectively accumulated under intermittent light and Chl b was accumulated during the subsequent dark incubation with CaCl 2. The change in chlorophyll-protein complexes during Chl b accumulation induced by CaCl 2 in the dark was investigated by SDS-polyacrylamide gel electrophoresis. Chlorophyll-protein complex I and free chlorophyll were major chlorophyll-containing bands of the cotyledons intermittently illuminated 10 times. When these cotyledons were incubated with CaCl 2 in the dark, the light-harvesting Chl a b- protein complex was formed. When the number of intermittent illumination periods was extended to 55, small amounts of Chl b and light-harvesting Chl a b- protein complex were recognized at the end of intermittent light treatment, and these two pigments were further increased during the subsequent incubation of the cotyledons with CaCl 2 in the dark compared to water controls.

Intermittent Lighting and In-Cage Broodiness Treatment for Turkey Hens in Cages

Cage-housed turkey hens were intermittently lighted (1L:2.25D:1L:2.25D:1L: 2.25D:1L:2.25D:1L:10D) or given 14L:10D per day. Broody hens were removed once a week to brightly lighted (>200 lx) floor pens in these groups. A third group was also given 14L:10D but an in-cage broody treatment (small, high-intensity lights (Tensor) suspended over the individual cages; >200 lx) was substituted for the floor pen broody treatment. No effect of light treatment was found on total eggs, number of normal (settable) eggs, and percentage of abnormal (not settable) eggs. No differences were associated with lighting treatments for the percentages of abnormal eggs classified as broken, weak-shelled, slab-sided, or extra-calcified. A greater percentage of abnormal eggs classified as shell-less was associated with the 14L: 10D and floor broody treatment.Four different strains of turkey hens were used in this study. Strain effects were noted for most of the traits listed above.

The Effects of Dietary Protein Levels, Ahemeral Light and Dark Cycles, and Intermittent Photoperiods on the Performance of Chicken Broiler Parent Genotypes

Two experiments were undertaken to estimate the effect of: 1) two dietary protein levels (13.6 and 15.4%) in breeder diets fed to commercial meat parent genotypes; and 2) 6 photo-periods involving both 24-hr and 27-hr (ahemeral) day cycles with single stage and intermittent lighting for birds housed in floor pens. It was concluded that the 13.6% protein breeder diet, which provided from 14.8 to 20.9 g of protein per bird per day and from 301 to 425 kcal of ME per bird per day, was adequate to support optimum performance.The ahemeral light treatment 14L:13D used from 168 to 448 days had a depressing effect on egg production and feed efficiency compared with the conventional 24-hr day cycle with 14L:10D light treatment. The 14L:13D treatment, however, did result in increased egg size and improved shell strength. The intermittent light treatments, whether ahemeral or 24-hr cycle, resulted in improved egg weight and shell strength. The ahemeral intermittent treatment (10L:12D:2L:3D) had the effect of depressing fertility and hatchability, whereas the 24-hr intermittent photoperiod (10L:9D:2L:3D) resulted in fertility and hatchability equal to or better than other treatment. It was concluded that the 24-hr intermittent light treatment (10L:9D:2L:3D) supported performance which was equal to or better than other light treatments including the 27-hr ahemeral day cycles. Furthermore, ahemeral day cycles resulted in large numbers of eggs laid on the floor (Ca. 50%). First and second order interactions appeared to be of minor importance.

Comparative Development of 11 Plants Grown under Various Fluorescent Lamps and Different Durations of Irradiation With and Without Additional Incandescent Lighting1

Abstract The relative efficiency of 7 types of fluorescent lamps was determined by the growth of 11 kinds of foliage and flowering plants. All 7 lamps – Cool White (CW), Warm White (WW), Gro-lux (GL), Gro-lux Wide Spectrum (GL-WS), Agrolite (AGRO), Vitalite (VITA), and an experimental (EXP) lamp – grew acceptable plants. As judged by fresh weight, CW and VITA were most effective on 6 of the plant species tested, WW and GL-WS on 5, AGRO on 4, GL on 2, and EXP on 1. Only 1 species, Tagetes, responded equally to all 7 lamps. As judged by promotion of stem and leaf lengthening, EXP was most effective on 5, WW on 3, GL and GL-WS on 2 and CW and VITA on 1 of the plant species. Stem and leaf growth of Saintpaulia and Tagetes were equal with all 7 lamps. The differences between the lamps however, were not as great as that caused by adding Incandescent (INC) to CW. In comparisons of continuous (6 or 12 hours) and intermittent (1 minute or 30 minute light-dark cycles for 12 hours) light treatments, combination of CW + INC for 12 hours increased the weight of 5 of the 8 plant species tested. Only Chlorophytum, Pilea, and Zebrina grew equally well under CW and CW + INC. These findings suggest that the restriction of active radiation to the 400-700 nm band width does not give the precise spectral requirements of photosynthetically sensitive of green plants. Any “white”-appearing fluorescent lamp may be used for growing plants. CW and WW were growth lamps and were more efficient in producing and maintaining light output over their useful lives than were the lamps with special designation.

The Influence of Intermittent Light on Growth of Broilers

Ten treatments involving continuous, constant intermittent, and variable intermittent light were conducted over five trials to determine the effect of these light regimes on weight, gain in body weight, and feed efficiency in broilers. The chicks were grown in battery brooders and were on experiment from one to seven weeks of age.In four trials in which both treatments were used, chicks grown with 30 min of light and 150 min of darkness per 3-hr cycle had an average body weight of 67 g more at seven weeks of age than those grown under continuous light. The differences were statistically significant (P<.05 or P<.01) in three of these trials.In four trials in which comparisons were possible, chicks grown under 30 min light and 150 min of darkness per 3-hr cycle averaged slightly, but not significantly, more (19 g) at seven weeks of age than those under other constant intermittent light schedules.Chicks grown under 30 min light and 150 min of darkness per 3-hr cycle averaged slightly more (23 g) than thos under variable intermittent light treatments. Differences were significant (P<.05) in only one of three trials in which comparisons were possible.Gain per unit of feed consumed from one to seven weeks of age was not significantly different among treatments within each trial.

Photocontrol of Anthocyanin Synthesis

The spectral sensitivity and the irradiance dependence of anthocyanin synthesis, a "high irradiance response," in cabbage (Brassica oleracea, cv. Red Acre) and tomato (Lycopersicon esculentum, cv. Beefsteak) seedlings exposed to continuous irradiation depend upon the length of the exposure. In cabbage, blue and red are more effective than far red when the irradiations are shorter than 12 hours and less effective than far red when the irradiations are longer than 12 hours. The irradiance dependence is negligible under red and becomes evident under blue and far red red only for exposures longer than 12 hours. Anthocyanin synthesis under intermittent light treatments, of efficiency comparable to that of continuous treatments, obeys the Bunsen-Roscoe reciprocity law and is a function of the dose (irradiance x time), rather than of the irradiance alone. The validity of the reciprocity relationships suggests that only one photoreceptor is responsible for the photocontrol of the response in the blue, red, and far red spectral regions. The characteristics of the response suggest that the photoreceptor is phytochrome, at least in cabbage.

The Influence of Intermittent Light on Growth Performance and Other Traits in Young Chicks

Treatments of 1/2L:3D, (1/2 hour light and 3 hours darkness), 1L:3D, 1L:5D lighting cycles and continuous light were used in three trials to grow 900 straight-run chicks from 7 to 35 days of age. Chicks on intermittent light had significantly (P < 0.05) greater gains than those on continuous light. There was no significant difference among treatments with intermittent light.Feed conversion for 1/2L:3D and 1L:5D treatments was significantly better than for the other two treatments.Weights of crop and gizzard contents at the end of dark period (8:00 a.m.) were not significantly different among treatments; however, at the end of the light (feeding) period, at 8:30 or 9:00 a.m., chicks on intermittent light generally had significantly more feed and fluid in the crop, but not in the gizzard, than chicks on continuous light.The crop (tissue) was generally significantly heavier in chicks from the intermittent light treatments. There was no significant difference among treatments for gizzard (tissue) weight.

PHOTOCONTROL OF ANTHOCYANIN SYNTHESIS: PHYTOCHROME, CHLOROPHYLL AND ANTHOCYANIN SYNTHESIS*

Abstract—Anthocyanin synthesis in cabbage and mustard seedlings depends upon duration and irradiance of the light treatment. The relative effectiveness of radiation in various spectral regions depends upon the length of the irradiation and decreases with increasing dose. In intermittent light treatments, far‐red light can reverse the promoting action of red light if the dark interval between successive irradiations is longer than one hour. If the length of the dark interval is less than one hour, far‐red applied immediately after each red irradiation, enhances anthocyanin accumulation. Anthocyanin accumulation under various light treatments seems to correlate, to some extent, with the rate of phytochrome decay, but not with chlorophyll production. Anthocyanin accumulation is inhibited by 2,4‐dinitrophenol and by the ammonium ion, but not by DCMU. The ammonium ion inhibits anthocyanin accumulation induced by a single, short red irradiation. This suggest that the ammonium ion may have a wider spectrum of action in vivo than in chloroplast preparations where it acts as a specific uncoupler of photophosphorylation. Streptomycin inhibits chlorophyll synthesis and enhances anthocyanin accumulation. These results suggest that there is very little, if any, interaction between photosynthesis and ‘high‐irradiance‐reaction’ anthocyanin synthesis in cabbage and mustard seedlings.