Effects Of Different LED Light Colors On Growth And Development,blood Hormone Levels And Cecal Microorganisms Of 0～21Day-old Broilers

The purpose of this study was to explore the effects of different LED light colors on growth and development,blood hormone levels and cecal microorganisms of 0～21day-old broilers.The experiment was conducted with a completely random design.A total of 360 healthy male AA broilers with similar body condition and weight were selected and divided into 4 groups with 6 replicates in each group and 15 broilers in each replicate.LED white light(W),LED green light(G),LED blue light(B)and LED blue-green composite light(BG)were used in each treatment group.The experimental period was 21 d,the light cycle of each treatment group was 23L:1D from 1 to 3 d,and the light cycle from 8 to 21 d was 16L:8D;light intensity is 20 Lux.The content of this study consists of three parts,and the results are as follows:(1)Effects of different LED light colors on the growth and development of 0～21day-old broilers.Under four light colors conditions,there was no significant difference in feed conversion ratio among groups(P>0.05).The final weight of the blue light group was significantly higher than that of the green light group(P<0.05),but not significantly different from the white light group and the blue-green composite light group(P>0.05).The average daily feed intake in the blue light group was significantly higher than that in the other three groups(P<0.05),but there was no significant difference among the other three groups(P>0.05).The average daily gain of blue light group was significantly higher than that of green light group and blue-green composite light group(P<0.05),but not significantly different from that of white light group(P>0.05).The average daily gain of white light group was significantly higher than that of green light group(P<0.05),but there was no significant difference between white light group and blue-green composite light group(P>0.05).There was no significant difference in chest muscle relative weight and the crosssectional area of chest muscle cell among the four groups(P>0.05).The relative weight of leg muscle in blue light group was the heaviest,which was significantly heavier than that in bluegreen composite light group(P<0.05),but not significantly different from that in white light group and green light group(P>0.05).The cross-sectional area of leg muscle cell of broilers grown in LED blue light environment was the largest,which was significantly higher than that of the other three groups(P<0.05).There was no significant difference in the effects of four light colors on intestinal relative length,relative weight and quality index of broilers(P>0.05).The villous height of jejunum and ileum in blue light group and blue-green composite light group was significantly higher than that in green light group(P<0.05),but there was no significant difference between blue light composite group and white light group(P>0.05).The crypt depth of ileum in blue-green composite light group was significantly lower than that in white light group and blue light group(P<0.05).The ileal villus crypt ratio in blue-green composite light group was significantly higher than that in white light group and green light group,but there was no significant difference between blue light group and blue light group(P>0.05).The results show that under the experimental conditions,compared with LED white light,LED color light had no obvious advantage on the feeding effect of broilers at 21 days of age.LED blue light environment is more conducive to food intake,promote muscle development and intestinal development,the effect of weight gain is the best.LED blue-green composite light is beneficial to intestinal development and has the potential to promote weight gain similar to LED blue light.(2)Effects of different LED light colors on blood indexes and hormone levels of 0～21day-old broilers.The effects of different light colors on blood biochemical indexes are mainly reflected in the regulation of carbohydrate and fat metabolism related indexes.The serum LDL-C content of broilers fed under LED green light was significantly lower than that of the other three groups(P<0.05).The content of GLU in blue light group was significantly lower than that in white light group and green light group(P<0.05),but there was no significant difference between blue light group and blue-green composite light group.That is,LED blue light can reduce serum glucose,green light can reduce serum LDL-C.There were no significant differences in the contents of MLT,GH,cortisol,T3 and T4 in blood of broilers under the four light colors(P>0.05).LED white light can stimulate the circadian rhythm of melatonin,growth hormone,and T3.LED blue light can stimulate cortisol to show a circadian rhythm trend.MLT,GH,cortisol,T3 and T4 did not exhibit circadian rhythm under LED green light and LED blue-green composite light.The results showed that LED white light could better stabilize the circadian rhythm for0～21day-old broilers.(3)Effects of different LED light colors on cecal microorganisms and cecal short-chain fatty acids of 0～21day-old broilers.Under the LED blue-green composite light environment,the contents of propionic acid,butyric acid,isobutyric acid and valeric acid in the caeca of broilers were higher(P<0.05).There was no significant effect on the relative abundance of cecal microorganisms at phylum level among the four groups(P>0.05).At the genus level,the relative abundance of Bacteroides in blue-green composite light group was significantly higher than that in green light group and white light group,but not significantly different from that of blue light group.The results showed that LED blue-green composite light could increase the content of short-chain fatty acids in cecum,the bacteria involved in SCFAs metabolic pathway in cecum were more developed,and LED blue-green composite light had better potential to promote the growth.In summary,this study believes that LED blue light and LED blue-green composite light are more suitable for 0～21day-old broilers to promote their growth and development.LED white light is conducive to stabilizing the circadian rhythm,and the application of LED green light is not effective.