Association Of LED Light Spectra With Broiler Chicken Growth And Related Mechanism

Precision management is the inevitable trend of the livestock and poultry husbandry.The majority of the related research focus on sensing the breeding information and building the shared platform.However,researchers pay a little attention to establishing the coupling models between accurate environment and poultry growth.Especially the model of light environment-poultry growth is limited,which is contributed to the poultry production decision.The lack of proper decision model cannot support an effective production process,although acquired adequate environment data.Therefore,the acquisition of coupling models under precise environmental parameters is one of the prerequisites for the precision farming.On the one hand,the chicken cones are hinged with each other as a "hyperuniformity",which make the chicken acquire a super vision system.On the other hand,precise control of LED(Light-emitting-diode),which represents the leader of a new generation of lighting source,provides a good carrier to establish those coupling models.Based on the high sensitivity of chicken to light and the precise control of LED,the association of LED light information with broiler growth models were investigated in the present study.Moreover,the underlying mechanism of the LED light information exerted on the chicken was proposed.The models and underlying mechanism may contribute to the production decision model.(1)The model of broiler growth-LED light based on meta-analysis integrated method The independent experiments conducted by different authors of the similar theme are difficult to remain absolute same with each other.To avoid the above contradiction,an effective data integrated method was adopted in the present study to integrate the data from the published papers about the LED light-broiler growth model and propose new hypothesis.Based on the subgroup analysis of the three type of control light lamps(Incandescent,fluorescent and white LED lamps),three sex type(Male,female and mixed),four light intensity level(0.1 W/m2,10 lux,15 lux and 45 lux),two light regimes(>23 L and<18 L),two rearing temperature(22 ?and 24 ?)and two diet nutrition(3100 kcal ME/kg and>3100 kcal ME/kg;175 g CP/kg and>175 g CP/kg),the effect of monochromatic LED light exerted on the broiler body weight is without relationship to those factors.Monochromatic LED light exerted a significant influence on the main production parameters(P<0.05).The greatest improvement of body weight(BW)and feed conversion rate(FCR)were obtained in blue LED light-treated broiler(10.66%,95%CI 8.79 to 12.53;-4.47%,95%CI-5.46 to-3.48;P<0.001),whereas the negative effect of BW and FCR were found in the red LED light-treated broiler.The production of international broiler strain was more sensitive to monochromatic LED light than local broiler strain.Meta-regression showed that the short light wavelength can promote the growth and development of broiler,whereas the long light wavelength decrease the growth and development of broiler.100 nm wavelength decrease resulted in 4.9%reduction of BW.Based on the above results,we proposed a new hypothesis that a proper ratio of blue-green-yellow light component may result in a further increase in the growth of broiler.(2)The model of broiler growth-LED light based on animal experiment We expose the Chinese local broiler strain("Meihuang";medium-growing line)to monochromatic red,yellow,green and blue LED light,to verify the results of meta-analysis.The results showed that short light wavelength(blue and green)can promote the growth of broiler,whereas the long light wavelength decrease the growth of broiler.Moreover,a negative relationship was found between the light wavelength and the BW(30d:BW=-0.154×wavelength + 460.1,R2= 0.8755).However,a difference between the rapid-growing line and medium-growing line to LED light was found in the present study,of which monochromatic red LED light resulted in a compensated growth of broiler during the period of later stage(>60 d).Further regression indicated a positive relationship between light wavelength and BW(72d:BW?0.164 x wavelength + 1081.2,R2 = 0.9251).(3)The model of broiler growth-GxB mixed LED light spectra By fabricating the mixed LED using growth-advantage LED spectra,we investigated the synergism and antagonism effects between the growth-advantage LED spectra and verify the hypothesis proposed by meta-analysis.The synergism or antagonism effects were dependent on the ratio of growth-advantage LED spectra.In comparison with pure blue and green LED light,the GxB mixed LED with high blue component ratio(>50%)resulted in synergism effect,whereas the GxB mixed LED with low blue component ratio(<50%)resulted in antagonism effect.(4)The model of broiler growth-W×Y mixed LED light spectra To avoid the negative effect of the growth-advantage LED spectra,the W×Y mixed LED with high luminous efficiency was fabricated,based on the human eye friendly spectra—yellow LED spectra.Further,we investigated the dose-response of the mixed LED light.The results showed that the yellow component ratio of the W×Y mixed LED have a significant effect on the BW,FCR,bone development,edible visceral weight and surface temperature(P<0.05).The consistent increase in yellow component ratio result in consistent in the change of growth parameters of broiler.Higher yellow component ratio resulted in greater effect on the BW,FCR,bone development,edible visceral weight and surface temperature,whereas lower yellow component ratio resulted in the reversed effect.(5)The physiological mechanism through which LED light spectra exerted on the broiler growth Combined with PCA(Principal Component Analysis)and the Pearson correlation analysis,we proposed the physiological mechanism through which LED light spectra exerted on the broiler growth.The results of PCA showed that the 144 physiological parameters could be clustered into four category.Quadratic relationships were found between illuminance period of yellow LED light source and the parameters,including abdominal fat weight,total cholesterol,triglyceride concentration,blood glucose levels,and P level(R2=0.8042-0.9954;P<0.01).BW were positively related with triglyceride concentration and abdominal fat weight(R2=0.464 and 0.816;P<0.01),suggesting illuminance period of yellow LED light enhancing abdominal fat weight and BW by increasing the triglyceride metabolism.Shank weight positively related with Ca level and BW(R2=0.509 and 0.659;P<0.05),suggesting illuminance period of yellow LED light improving BW by increasing the Ca absorption and enhancing bone development.(6)The feed intake-manure emission mechanism through which LED light spectra exerted on the broiler growthThe monochromatic LED light spectra play a vital role in affecting the water intake of broiler(P<0.05),whereas have no significant influence on the feed intake,metabolic energy and crude protein of dietary(P>0.05).For the manure emission characteristic,broiler exposed to different monochromatic LED light produced significant difference in manure production(P<0.05).Pearson correlation analysis demonstrated that manure production was positively related with feed intake(R2=0.841;P<0.01),water intake was positively related with moisture content of manure(R2=5257;P<0.01)and volatile solid was positively related with moisture content of manure(R2=0.428;P<0.01),Therefore,the monochromatic LED light spectra can improve growth of broiler by shifting the feed intake-manure emission to improved growth rate and FCR.(7)The behavior mechanism through which LED light spectra exerted on the broiler growth We have investigated the mechanism from the view of behavioral rhythm and its inherent adaptability contact with broiler growth.The measurement of behavior showed that broiler treated with green and blue LED light expressed eating behavior as high as 34.0%(14d),32.3%(28d),31.5%(42d)and 36.2%(14d),38.7%(28d),40.5%(42d),whereas broiler treated with red LED light expressed standing behavior as high as 32.2%(14d),56%(28d)and 50%(42d).The analysis of behavioral rhythm demonstrated that the broiler concentrated in Afternoon,Evening and Night(24.1%-41.4%),of which those presence are expressed as no-growth behavior such as walking and standing.The broiler is present and eat equally at the Morning,Afternoon,Evening and Night(21.7%-25.2%;14.1-35.2%)in blue light stimulation.Moreover,the broiler eating behavior remain a high percent(14.1%)even in Night in blue light stimulation.Therefore,on the one hand,the blue light can decrease the amount of no-growth behavior expression and the majority of the energy was used to support growth.On the other hand,though the light spectra did not change the amount of feed intake,the eating rhythm was changed by blue light,resulting in a prolonged eating period.Through the above two pathways,the digestion and absorption of dietary was improved and the growth was enhanced.