Broiler performance when reared under various light sources

Effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights

Limited data are available for comparing light-emitting diode (LED) bulbs that are currently available in commercial broiler production facilities. We evaluated the effects of color temperatures (kelvin) of LED bulbs on growth performance, carcass characteristics, and ocular development indices of broilers grown to heavy weights (>3.0 kg). The experiment had a randomized complete block design. Four treatments consisted of 3 LED light bulbs (2,700 [warm LED]; 5,000 [cool LED 1]; and 5,000 K [cool LED 2]) and incandescent light (2,010 K [ICD], standard) from day zero to 56 d of age. A total of 960 Ross×Ross 708 day-old chicks were equally and randomly distributed into 16 environmentally controlled rooms at 50% RH (30 males and 30 females/room). Thus, each of the 4 treatments was represented by 4 rooms (4 replicates) per trial. Feed and water were provided ad libitum. All birds were fed the same diet. Ocular specimens were collected on d 42 for development and histopathologic examination. Blood samples were collected on d 21, 28, 42, and 56 to determine plasma corticosterone. On d 56, twenty birds from each room (10 males and 10 females) were processed to determine weights and yields. The BW and BW gain (BWG), live weight, and carcass weights of birds reared under cool LED 1 were different in comparison to birds reared under ICD (P<0.05). However, feed intake (FI), feed conversion ratio (FCR), and mortality were not affected by treatments. The treatments did not affect fat, breast and tender weights, and yields. In addition, ocular development indices and plasma corticosterone concentrations were not affected by treatments, suggesting the LED light bulbs we evaluated did not compromise the welfare of the birds. It was concluded that cool LED 1 may be a better potential replacement light source in comparison to ICD on performance, but it may be equal when compared to other LED light sources examined in this study.

Monochromatic light stimuli during embryogenesis enhance embryo development and posthatch growth

Photostimulation with green light accelerated BW and muscle development of broilers. In experiment 1, temperature sensors were inserted into 50 broiler eggs. The eggs were placed under 5 green light-emitting diode (LED) lamps at an intensity of 0.1 W/m2 at eggshell level for 5, 10, 15, 20, and 25 min (n = 10). Egg temperatures were recorded continuously. A high correlation was found between lighting period and egg temperature elevation, and an intermittent light regimen of 15 min on and 15 min off was found to eliminate light-induced egg overheating. In experiment 2, the effect of in ovo green light photostimulation on embryonic development was studied. Five hundred fertile eggs were divided into 2 groups: the first was photostimulated with green light from 5 d of incubation until hatch (0.1 W/m2 intensity) and the second was incubated in the dark. In ovo green light photostimulation caused a significant elevation in BW and breast muscle weight during embryo development and posthatch until 6 d of age. In experiment 3, 240 fertile broiler eggs were divided into 2 groups as described in experiment 2. At hatch, chicks from each in ovo light treatment were divided into 2 subgroups: the first was reared under green light and the second under white light. In ovo photostimulation with green light enhanced BW and breast muscle weight. However, rearing under green light did not have any synergistic effect on BW. Collectively, the results suggest that stimulation with green light enhances development and growth in chicks and that the best effect is achieved when this stimulus is provided during incubation.

Effect of embryonic photostimulation on the posthatch growth of turkey poults

Artificial illumination, including light quality, is important in modern meat-type poultry management. In the present study, the effect of in ovo monochromatic green light photostimulation on posthatch growth of turkey poults was investigated. In experiment 1, 182 turkey eggs were divided into two light treatment groups (n = 91). The first group was intermittently photostimulated (3 min on and 3 min off) with green light provided by five light-emitting diodes (LED) per egg at 0.1 W/m2 at the upper eggshell surface. The second group was incubated in the dark and served as the control. Posthatch BW were recorded at 0, 2, 6, 13, 20, 28, 35, and 59 d of age. A heavier BW, occurring at 28 d of age and persisting until the end of the experiment (59 d of age), was observed in the in ovo green light stimulated females as compared to their corresponding controls. In experiment 2, 273 turkey eggs were divided into three light treatment groups (n = 91). The first group was intermittently photostimulated (15 min on and 15 min off) with green light provided by seven LED per egg at 0.14 W/m2. The second group was photostimulated with white light provided by one mini-incandescent lamp per egg at light intensity and schedule similar to the first group. Eggs of the third group were incubated in the dark and served as controls. Posthatch BW were recorded at 0, 7, 14, 28, 42, 56, and 79 d of age. No differences were found among the BW of males incubated under different light conditions. As in experiment 1, female turkeys with stimulated green light in ovo had greater BW compared to their corresponding control and white light groups from 28 d of age until termination of the experiment at 79 d of age. Breast muscle weight was greater in female turkeys incubated under green light when compared to white and dark incubation treatment groups. We suggest that in ovo green light photostimulation enhances the posthatch BW of female turkey poults.

Effect of light source and regimen on growing broilers

The aim of this study was to determine the effect of different light sources and light schedules on the growth and quality of commercial broilers. In each experiment 810 broiler chicks were divided into 3 groups, 3 replicates per group. All were reared at 20 lux. Body weight and food consumption were recorded weekly. Experiment 1. Birds were reared under 3 light sources: incandescent light bulb, warm-white fluorescent light tube or warm-white mini-fluorescent light bulb. Experiment 2. Birds were reared on 3 light schedules. 23 h light and 1 h dark (23L: 1D) throughout; an increasing light schedule with initial 23L:1D then 8L: 16D increasing daylight gradually to 16L:8D or an intermittently increasing daylight schedule (16:8P) where light and dark periods were shorter but portioned to achieve the same total hours per day up to 16L:8D. Broilers reared under mini-fluorescent light bulb were heavier than those under fluorescent tubes or incandescent bulbs by 49 d. Until 42 d of age, photoperiod had no effect on growth. However, at 49 d broilers reared under 16:8P and 16L:8D regimens were heavier than those or 23L:1D. At 42 d, female broilers on 23L:1D, were heavier than those on 16L:8D and 16:8P. Mortality was higher in groups on 23L:1D than on 16L:8D on 16:8P. At 49 d incidence of leg condemnation was higher in the 16:8P group. However, skin damage was lower in this group than in those on 23L: 1D and 16L:8D.

Spectral sensitivity of the domestic fowl (Gallus g. domesticus)

1. The spectral sensitivity of 7 broiler fowl was determined in a behavioural test. 2. Initially the birds were trained to receive a food reward by pecking at a clear, Perspex panel behind which was a light stimulus (circular, diameter = 9 mm), originating from a tungsten-halogen lamp. Subsequently, they were trained to choose between 2 panels only 1 of which was lit; the assignation of light and dark on each panel was randomly ascribed between trials. The colour of the lit panel was determined by the wavelength of the light transmitted through one of 13 closely defined narrow bandwidth filters between 326<lambda<694 nm. The flux of photons and hence the intensity of the stimulus received by the bird could be controlled by changing the voltage across the lamp. The photon flux was gradually reduced until the birds failed to detect accurately the lit panel. Success was defined as a choice of the lit panel 9 or more times in a sequence of 10 trials, providing that the sequence contained at least 4 changes in the position of the stimulus. 3. Generally, the birds showed a peak sensitivity between 540<lambda<577 nm. The results agree with electrophysiological data between 507<lambda<694 nm and psychophysical data between 500<lambda<700 nm but our data showed higher sensitivities between 380<lambda<507 nm compared with electro-physiological findings. 4. Our findings confirm that broilers can 'see' into the UV(A) range and that their spectral sensitivity is different to the human. The implication of this is that the measurement of light intensity in poultry housing using the lux unit does not accurately describe the intensity perceived by fowl. 5. Experimenters using colour, for example differently coloured lighting or food, need to account for this different sensitivity when interpreting their results.

The effects of color and intensity of light on behavior and leg disorders in broiler chickens

Two experiments were conducted to investigate whether manipulating the wavelength and intensity of light could be used to increase activity and reduce locomotion disorders in meat chickens. The first experiment examined the effects of wavelength and intensity of light on bird activity. Male (n = 60) and female (n = 48) chicks were reared from Day 1 to 35 in red or blue light at three intensities. Walking, standing, drinking, aggression, and wing stretching increased with intensity in red but not blue light. In the second experiment, the effects of stimulating bird activity with bright red light in the early or late part of the rearing period on locomotion and leg disorders were examined. Male (n = 24) and female (n = 24) chicks were reared from Day 7 in either dim blue light to Day 55 (Treatment All Blue), or bright red light to Day 22, followed by dim blue light to Day 55 (Treatment Early Red), or dim blue light to Day 22, bright red light to Day 38, and dim blue light to Day 55 (Treatment Late Red). Bright red light considerably increased walking, feeding and stretching, particularly when applied early in the growth period. There were residual effects on activity after the birds had returned to dim blue light. Red light increased growth when provided at the beginning of the rearing period, but decreased it when provided later. Bone strength was reduced in treatment Late Red, which appeared to be related to the lower body weights of birds in this treatment. Bone length, weight, and torsion were not affected by treatment, but the tibia plateau angle was reduced by Early Red light in female birds. In Treatment All Blue, there was a high incidence of gait abnormalities, which was reduced by Early and Late Red light. It is concluded that rearing meat chickens in bright red light increases activity, which reduces locomotion disorders in the late rearing period. It is preferable to provide the stimulatory light early in the rearing period.

Relationship between age of commercial broiler chickens and response to photostimulation

A study was conducted to determine the relationship between age of commercial broiler chickens and response to photostimulation. The chickens were brooded collectively for 1 wk and then separated into five light treatment groups with each group replicated three times using a completely randomized block design. After Week 1, the five light treatments applied were: 6, 5, 4, 3, and 2 wk of continuous supplementary lighting, respectively. Chickens were fed a corn-soybean meal basal diet containing 22% CP and 3,300 kcal ME/ kg of feed from day old to 7 wk. At 7 wk of age, chickens in Group 5 treated with supplementary light during the last 2 wk of growth had the highest mean BW when the data on sexes were combined. When the data were separated by sex and analyzed, only male chickens showed a significant response to photostimulation and this was observed at 4 wk of age. Chickens in Group 5 had the best feed conversion with less mortality and no leg disorders. There were no significant differences among the relative organ weights among the treatment groups except for the pancreas. The pancreas taken from Group 5 had the smallest weight relative to BW. There were no significant differences in breast, thigh, drumstick, and wing weights when expressed as relative weight. However, there were significant differences when expressed as absolute weight. The breasts taken from birds in Group 5 were significantly heavier than the control breasts.

Effects of Lighting on the Welfare of Domestic Poultry: A Review

Four aspects of lighting which may influence the behaviour and physiology of housed poultry are light intensity, photoperiod, light source and wavelength. These factors are frequently manipulated in an attempt to improve productivity and to facilitate management practices. This review examines the effects of such manipulation upon the welfare of the birds. The majority of papers on lighting in poultry houses deal with their effects upon performance, rather than on factors associated with behaviour and health which may impinge upon welfare. Data about the preferences of birds for different lighting conditions are almost entirely lacking, but the practice of housing birds in relatively low light intensity is considered likely to lead to sensory deprivation in species where vision is important. Tentative recommendations are given pending the results of future research as to appropriate light intensity, photoperiod and light sources for domestic poultry.

Effects of imperfect albinism (sal-s) on growth in a heavy line of chickens

Four trials compared growth, feed efficiency, and mortality of albino (sal-s) and nonalbino chickens under conditions approximating those used commercially for broilers. Early body weight reductions of albino chicks were substantial, but by a normal market age for broilers in North America, albinos weighed only 3 to 5% less than nonalbinos. The early mortality rate of albinos was elevated. Overall feed efficiency was not affected by the sal-s gene. An increased incidence of lesions of the navel, hocks, and nares was observed, but regression analyses showed them to be relatively unimportant in the determination of body weights. Heritability estimates showed that the lesions would be very difficult to eliminate through selective breeding. It is proposed that the gene could be used to sex either commercial broilers or their dams.