The Impact of Different Color LED Light in Layer Production Rodrigo G. Garcia¹, Rodrigo Borille¹, Irenilza A. Naas¹, Ibiara C. L. Almeida Paz¹, Fabiana R. Caldara¹, Ana F. B. Royer¹, Mayara R. Santana¹, Nilsa D. S. Lima¹, Sandro Colet¹ ¹Federal University of Grande Dourados, UFGD, Brazil E-mail: [email protected] Abstract: Artificial lighting is one of the most powerful management tools available to commercial layer producers. It allows anticipating or delaying the beginning of laying, improving egg production, and optimizing feed efficiency. This study aimed at comparing the performance of commercial layers subjected to lighting using different LED colors, and standard incandescent lamps. The study was carried out inside a layer house, which was divided into isolated environments in order to prevent any influenced from the neighboring treatments. In total, 360 Isa Brown® layers, with an initial age of 56 weeks, were used in the trial. The following light sources were used in the treatments: blue LED, yellow LED, green LED, red LED, white LED, and 40W incandescent light. Birds in all treatment were subjected to a continuous lighting program 17 l: 5 d, and they were fed a corn and soybean meal-based diet. A totally randomized experimental design was applied, with 24 treatments (6 light sources and 4 periods) and with three replicates. Egg production (%) was different (p ≤ 0.05) among treatments, with the best results obtained with red LED, white LED, and incandescent light sources. Egg weight, feed intake, and internal egg quality (albumen height, specific gravity, and Haugh units) were not influenced (p > 0.05) by the light source. The replacement of incandescent light bulbs by white and red LED light bulbs did not cause adverse impact on the egg production. Keywords: Artificial lighting, commercial layers, egg weight, Haugh units

Introduction Birds are light sensible animals and present physiological characteristics that can be changed through the management of lighting. In layers these characteristics may interfere in the egg production and quality, and it is related to type of visible spectrum emitted by the light source, from which some colors present different output stimuli than others (Nicholls et al., 1988). Study using LED in birds’ production has demonstrated that different colors of light source may influence some production factors (Er et al., 2007). The authors found that green LED light source improved the quality of eggshell from commercial layers. Besides improving economical investment through the increase in durability and the low use of energy, LED light source may help the improvement of layers aviaries (Nicholls et al., 1988). This research aimed at evaluating the influence of different colors of LED light source in aviaries of layer production, compared to the use of standard incandescent light source. Material and Methods

The research was developed inside an experimental layers aviary at the Experimental Station of the College of Agrarian Sciences of the Federal University of Grande Dourados, Brazil. The trial lasted 112 days which were divided into 4 periods of 28 days. The aviary was an open sided house with 36 conventional layers’ cages. All cages had drinker nipple type and gutter feeders. The ambient was divided using a cardboard walls to avoid the light entrance in the boxes with each treatment and consequent interference in the studied effect. It was used 360 layers from the commercial strain Isa Brown® with ages of 56 (initial) and 72 weeks (final). Six repetitions of each treatment were used. The trial treatments are displayed in Table 1. The light program was 17 l: 5d and the light intensity was standardized in 40 lx for all treatments. Table 1. Trial treatments description with standardized light intensity Treatment Light source characteristics T1 LED bulb color blue T2 LED bulb color yellow T3 LED bulb color green T4 LED bulb color red T5 LED bulb color white Control Fluorescent bulb (40W) The layers were fed with fodder containing corn and soybean using the nutritional recommendation of Rostagno (2005). Eggs were collected once a day and the egg production was estimated in percentage. The mean fodder consumption was registered in an adapted sheet and expressed in grams per bird per day. In the last day of each period 10 good graded eggs from each treatment and repetition was chosen, identified and weighted using a digital scale with precision of 0.01g. Egg quality was analyzed used the following parameters: specific gravity, albumen height and Haugh unity, as described by Haugh (1937): UH = 100 log (H + 7.57 – 1.7 PO0.37) Where: UH: Haugh unity; H: albumen height (mm); and PO: egg weight For the statistic analysis a random design was adopted in sub divided samples. Data were subjected to the ANOVA and processed using the statistical software Assistat (Silva, 2012). For comparing the means it was adopted Tukey test at 5%. Results and Discussion Mean egg production (%) were higher in the treatments T1, T5 and control than in the other treatments, being 4.83%, 5.55% and 5.17%, respectively higher than the results in T3, which presented the smaller result (Table 2). Results from T1 and T2 were similar (p > 0.05); however, they were lower (p ≤ 0.05) than those from T4, T5 and control. The weight of eggs was not influenced (p > 0.05) by the sources of light; however, there was a significant effect in the periods and the first period presented worst results than the second.

Table 2. Egg production per day (%) and mean egg weight (g) from commercial layers reared under different LED colors and compared to incandescent light. Period (28 days) Treatment 1

2

3

4

Average

T1

91.66

49.68

88.02

66.57

90.62 66.70

86.25 65.95

89.14b 62.23

T2

89.16

51.63

88.75

64.04

89.58

61.58

89.37 68.97

89.21b 61.55

T3

86.97

49.41

86.87

66.93

88.33

66.88

85.20 66.38

86.84c 62.40

T4

92.18

53.25

91.56

66.81

91.25

68.87

90.00 67.30

91.25a 63.07

T5

92.50

53.25

91.77

66.51

92.29

67.65

91.25 67.16

91.95a 63.64

Control

90.72

52.87

92.18

64.71

91.45

70.50

91.97 67.13

91.58a 63.80

Average

90.53a 51.02b 89.86ab 65.93a 90.59a 67.03a

89.01b 67.15a

Coefficient of variation for the periods (%)= 4.11 and 7.59 respectively, and for the sources of light = 4.24 and 7.21, respectively. Sources of light: T1, T2, T3, T4, T5 and control. Means followed by the same letter in the column did not differ by Tukey test at 5%.

Fodder consumption was not affected by the source of light or period analyzed (Table 3). This may indicate that the layers did not change their feeding behavior when exposed to the different types of light sources. Table 3. Fodder consumption of commercial layers (g/bird/day) reared under different types of light sources. Period (28 days) Treatment 1

2

3

4

Average

T1

0.113

0.114

0.117

0.112

0.114

T2

0.112

0.118

0.115

0.122

0.117

T3

0.114

0.109

0.117

0.114

0.113

T4

0.114

0.113

0.116

0.117

0.115

T5

0.117

0.112

0.116

0.117

0.116

Control

0.113

0.113

0.117

0.116

0.115

Average

0.114

0.113

0.116

0.116

Coefficient of variation for the periods (%)= 4.11, and for the sources of light = 4.24. Sources of light: T1, T2, T3, T4, T5 and control.

No difference was found (p > 0.05) between the tested sources of light in the egg quality (albumen height, specific gravity and Haugh unity) as seen in Tables 4 and 5. However, the results of the compared periods were different (p ≤ 0.05). The mean values of period 1 (8.39 mm) and period 2 (7.81 mm) were higher than the means of period 3 (7.03 mm), which presented the worst result. Egg specific gravity (Table 5) also were not different (p