An experiment was conducted to determine melamine residual levels in the tissues of broiler chickens fed diets containing graded levels of melamine. Ten experimental diets were developed to contain 0, 2, 5, 10, 20, 50, 100, 200, 500, and 1,000 mg of melamine/kg of diet. Each diet was offered in 4 replicate cages (12 birds per cage) from d 1 to 42, followed by a 7-d feeding of a withdrawal diet that contained no melamine. On d 28, 42, and 49, one bird per replicate was killed and tissue samples from the breast meat, liver, and kidney were collected for the determination of residual melamine levels. Throughout the 42-d feeding period, feeding diets containing graded levels of melamine had no effect (P>0.05) on the weight gain, feed intake, feed conversion ratio, and mortality of broiler chickens. Residue levels of melamine in broiler tissues at d 28 and 42 were below the detection limit when the diets contained

A previous study demonstrated that birds that are exposed to light at night develop advanced reproductive systems. However, spectrum might also affect the photoperiodic response of birds. The present study was aimed to investigate the effects of spectral composition on the growth and reproductive physiology of female breeders, using pure light-emitting diode spectra. A total of 1,000 newly hatched female avian breeders (Gallus gallus) were equally allocated to white-, red-, yellow-, green- and blue-light treated groups. We found that blue-light treated birds had a greater and faster weight gain than did red- and yellow-light treated birds (P = 0.02 and 0.05). The red light expedited the sexual maturation of the chicks, whose age at sexual maturity was 7 and 14 days earlier than that of the green- and blue-light treated birds, respectively. The accumulative egg production of the red-light treated birds was 9 and 8 eggs more than that of the blue- and green-light treated birds. The peak lay rate of the red-light treated groups was significantly greater than the blue-light treated birds (P = 0.028). In conclusion, exposure to short-wavelength light appears to promote growth of female breeder birds, whereas exposure to long-wavelength light appears to accelerate reproductive performance.

LED has shown great advantages in poultry husbandry. This study focused on the behavioral preferences and production performance of chicken broilers reared under unevenly distributed yellow LED light. Four pens were divided into two groups adopting respective maximum light intensities (MLIs, 60 lx and 30 lx). Because of different distances from the installation position of the LED pipe, each pen was distributed with unevenly distributed light. Each pen consisted of four subzones indicated by their light intensities-high intensity (HI), medium intensity (MI), low intensity (LI) and weak intensity (WI). Four subzones were the same size and provided with a feeder and a drinker, respectively. The broilers moved freely across the four subzones. No significant differences in body weight (BW), uniformity of final BW and feed conversion ratio (FCR) were observed between the two experimental groups. However, greater feed intake and water intake were found in HI than those in other subzones. The drinking preference changed with age for four subzones and was more likely to appear at the later stage, despite substantial fluctuations within the replicates. The feeding preference was more constant than the drinking preference and appeared mainly at the early and middle stages of this study. These findings could provide implications for broiler production reared under unevenly distributed LED light condition.

Light-emitting diode (LED) light sources show a high potential for replacing traditional incandescent lamps in broiler production facilities. LEDs offer clear advantages in energy efficiency. However, the application of LED technology to broiler production is restricted because of the absence of research about its uneven distribution of light intensity and subsequent impacts on broilers. This study investigated the effect of unevenly distributed yellow LED lights with different light intensities on the behavioral preferences and performance characteristics of female broilers. Four pens were developed to provide two unevenly distributed lighting environments with maximum light intensities (MLIs) of 90 and 60 lx in a study including replicates. Each pen consisted of four subzones characterized by their light intensity, including three subzones of high intensity (HI), medium intensity (MI), and low intensity (LI) in the lighting area (LA) and one nonlighting area (NA). Thirty female broilers were reared in each pen and were free to eat, drink, and stay in any subzone. No significant difference between the 90 and 60 lx experimental groups was found in feed conversion ratio (FCR), body weight (BW), uniformity, or growth ratio. The birds in both groups tended to drink water (p < 0.05) in the LI and MI subzones during the first three weeks. The preference of the birds then shifted to the MI and HI subzones with the growth of the birds despite substantial fluctuations within replicates. In both groups, feed intake was less affected than water intake by the uneven distribution of light intensity. The birds showed a transient feeding preference for LI and HI at young and old ages, respectively. The video data demonstrated that the birds showed a diurnal preference for LI (<2 lx) and a nocturnal preference for MI. The daily overall results showed higher preferences for NA in both groups. The preferencebased lighting regimes indicated that the birds need less lighting time during the daytime than the nighttime. This study can provide further knowledge about broilers' performance and behavior patterns in LED lighting environments, thus providing reference information for the configuration of LED arrays in commercial poultry production.

No abstract