This study observed the effect of different LED light colour on the behaviour and fear responses of broilers. In experiment 1, 400 broilers were placed into eight different light treatments. In experiment 2, six different light colours with five different age groups were considered. In experiment 1, use of a red and red-yellow mixed light significantly increased walking behaviour. Consequently, sitting and standing behaviour were found to be wavelength dependent, whereby short wavelength (blue, green-blue) treated birds spent more time sitting and standing than that under long wavelength (red, red-yellow). Consistently in experiment 2, birds spent more time feeding under the green treatment than with other treatments. Walking behaviour was significantly decreased and sitting and standing behaviour was increased under the blue light. Age also influenced the behaviour of broiler: young birds were more active than older birds. In addition, ground pecking and wing stretching behaviour were influenced by the wavelength of the light. Time of day did not influence the behaviour of the broilers. Under the red and red-yellow light treatments, birds spent longer in tonic immobility. Thus, the results suggest that red and red-yellow light activated the broiler's movement and fear responses while blue and greenblue decreased the movement and they spent more time sitting.

We evaluated the effect of monochromatic and combined light emitting diode (LED) light colour on performance, ovarian morphology, and reproductive hormone and biochemical blood parameters in laying hens. A total of 600 Hy-line Brown pullets, 12 weeks of age, were divided (25×4×6 = birds × replications × treatments) as follows: red (R), green (G), blue (B), and combinations of R→G and R→G→B treatments. Fluorescent white light (W) was the control. The results showed that higher egg production was found under the monochromatic R and combination R→G treatments, and that heavier eggs were laid by the B and G treatments (P<0.05). Consequently, better feed conversion ratio was attained in the R→G treatment. Serum follicle stimulating hormone and 17 -estradiol levels were significantly higher in the R and R→G treatments. B treated birds came into production 15 days later than those treated with R light. Organ weight (ovary and stroma) and ovarian follicle numbers (1-3 and 4-6 mm) were significantly higher in R treated birds, as well as serum glucose and triglyceride contents. Serum IgG concentrations and the heterophil to lymphocyte ratio were not influenced by light colour. In these laying hens, 14 h R with 2 h G light in the later part of the day increased reproductive hormone levels, ovarian weight, and follicle number and hence increased egg production. Thus, these results suggest that a combination of R→G light may be comparable with monochromatic R light to enhance egg production in laying hens.

The present study evaluated the effect of monochromatic and combinations of light emitting diode light color on the performance and behavior of laying hens. At 12 weeks of age, 600 Hy-line Brown pullets were randomly divided into eight lighting treatments with three replicates of 25 birds in each room. The lightning was set-up as follows; white (W, control; 16 h/d), red (R; 618-635 nm; 16 h/d), green (G; 515-535 nm; 16 h/d), blue (B; 455-470 nm; 16 h/d), red→ green (R→G; 14 h→2 h/d), red→ blue (R→B; 14 h→2 h/d), red→ green→ blue (R→G→B; 12 h→2 h→2 h/d) and red→ blue→ green (R→B→G; 12 h→2 h→2 h/d) light treatments. The light colors significantly influenced egg production, which was higher for the combination R→G (89.56%) and monochromatic R (87.34%) and lower in the G (85.26%) and B (83.75%) light treatments. Conversely, egg weight was remarkably heavier in the B and G light treatments than those of monochromatic R and combination treatments. Concurrently, better feed conversion ratio was found for the combination R→G→B and R→G and the monochromatic R light treatment. Egg shells were significantly pigmented by the combinations of R→B→G and R→G→B. Furthermore, egg shell breaking strength increased following the G treatment. Higher frequencies of ground pecking, ground scratching, and tail wagging were observed in the R group and these behaviors were less frequent in the B groups. Birds under G and B lights spent a longer time perching. These results suggest that a combination of R→G and monochromatic R light enhanced egg production. In contrast, R light activated the bird's movement, whereas B light decreased movement, and birds spent a longer time perching.

An experiment was conducted to investigate the effect of monochromatic and mixed light color on performance, bone, meat quality, blood properties and immunity of broiler chicks. In experiment 1, 1,200 Ross×Ross 1-day old chicks were equally allotted to the following 8 light treatments with 3 replications: red (R), yellow (Y) green (G), blue (B), mixed R×Y, Y×G, and G×B light colors. Fluorescent white light was the control. Experiment 2 considered similar treatments (6 treatments with 4 replications) except R and R×Y were not tested. Light (24 L: 0 D) and intensity (0.1 watts/m 2 ) was maintained at the bird's head level. Weight gain during weeks 2-3 increased in the G and G×B groups (P＜0.05). Weight gain was higher (P＜0.05) in the B and G×B treatments at week's 4-5. Similar weight gains were noted in experiment 2. Monochromatic B and the G×B mixed lighting groups showed increased meat pH, decreased shear force, and L* in both experiments. Birds reared under B light had reduced (P＜0.05) blood glucose in both experiments and reduced HDL and LDL levels in experiment 1. Circulating levels of IgG and IgA were increased with exposure to the monochromatic Y and G treatments at 21 days and to B light at 35 days of age (P ＜0.05). In conclusion, the mixed G×B lighting treatment enhanced growth performance and showed similar bone and blood properties and immunity of broiler chicks compared to those of monochromatic G or B light.

Pigmentation genes such as TYR (tyrosinase), TYRP1 (tyrosinase-related protein 1), DCT (previously TYRP2, or tyrosinase-related protein 2), ASIP (agouti) and MC1R (melanocortin receptor 1) play a major role in cattle coat colour. To understand the genotypic profile underlying coat colour in native Korean Hanwoo cattle and Angus black cattle, portions of the above-mentioned genes were amplified. Sequence analysis revealed variation in the TYRP1 (exon 5) and MC1R genes. Restriction enzyme analysis of these two genes could distinguish between different colours of Hanwoo cattle. Quantitative estimates of melanin and eumelanin in hair from three different-coloured Hanwoo phenotypes and Angus black showed significant differences at the breed and phenotypic levels. Finally, sequence variants in MC1R were associated with total melanin and eumelanin in breeds as well as in Hanwoo phenotypes.