| China is the largest country with the production of bamboo resources and bamboo products in the world.Bamboo leaves are a natural plant for both food and medicine use,and there is a very broad prospect in the research and utilization of bamboo resource.This study explored the effects of dietary supplementation with different doses of bamboo leaf extract(BLE)on growth performance,antioxidant capacity and meat quality of broilers,and studied the appropriate dose of BLE in broiler feed,and then the appropriate dose were severe amplified that was added into the basal diet to explore the tolerence of broilers for BLE,The broiler experiment was divided into two designings,and this study consists of the following four parts.Part one was conducted to investigate the effect of dietary supplementation with different doses of BLE on growth performance,organ index and slaughter performance in broiler chickens.A total of 576 one day old(Arbor Acres)AA broilers with similar body weight were selected and divided into 6 groups,with 6 replicate each,and a replicate containing 16 broilers.A control(Con)group was fed with basal diet,and the other five groups were supplemented with 0.10%,0.20%,0.30%,0.40%and 0.50%BLE into basal diet respectively.A total of 42 day experimental period were divided into start phase and grower phase,with 21 day each.Results:(1)During the start phase of the experiment,compared with the Con,the average daily feed intake(ADFI)of broilers in groups 0.20%and 0.50%was significantly increased,increasing by 4.29%and 3.43%(P<0.05);At 21 days of the age,the average body weight(AB W)in group 0.50%was increased significantly by 6.64%(P<0.05).During the grower phase of the experiment,compared with the Con group,the ADFI of broilers in groups 0.20%and 0.50%was significantly increased by 7.46%and 7.23%(P<0.05);the average daily weight gain(ADG)of the broilers was quadratic significantly increased,Among them,the ADG of the groups 0.10%,0.20%and 0.50%were significantly higher than the Con group by 9.48%,13.84%and 10.00%(P<0.05);the broiler feed gain ratio(F/G)of the groups 0.10%and 0.20%was significantly lower than that of the Con group.(P<0.05);except for the group 0.40%,the ABW of broilers in the other BLE groups was significantly higher than that in the Con group,and groups 0.20%and 0.50%were improved by 13.00%when compared with Con group(P<0.05).During the whole period of the experiment,compared with the Con group,the ADG in group 0.20%was significantly increased by 10.54%,and F/G was significantly reduced by 2.30%(P<0.05).(2)At 42 days of age,compared with the Con group,except for the group 0.50%,the liver index of the other BLE groups decreased significantly by 0.38%,0.43%,0.44%,and 0.49%(P<0.05);the heart index of the group 0.50%was significantly lower than that in the Con group(P<0.05);the spleen index of the groups 0.20%and 0.40%was significantly lower than that of the Con group(P<0.05).(3)At the age of 42 days,compared with the Con group,except for the group 0.30%,the eviscerated rate of the other BLE groups was significantly increased by 2.86%,2.49%,2.25%,and 3.11%(P<0.05);The breast rate in groups 0.30%and 0.50%was significantly higher than the Con group(P<0.05);BLE supplementation significantly reduced the abdominal fat rate of broilers by 0.43%,0.38%,0.32%,0.38%,and 0.41%(P<0.05).Part two was conducted to investigate the effect of dietary supplementation with different doses of BLE on serum biochemistry and antioxidant capacity in broiler chickens.The experiment design is same with part 1.Results:(1)At 21 days of age in broilers,compared with the Con group,the serum total cholesterol(TC)content of broilers in groups 0.20%and 0.30%was significantly reduced by 17.01%and 9.55%,respectively(P<0.05);The serum urea nitrogen(BUN)content of broilers in each BLE group was significantly reduced by 33.33%,37.68%,46.38%,44.93%and 56.52%(P<0.05);In addition,the serum total protein(TP)content of broilers in groups 0.40%and 0.50%was significantly increased by 24.45%and 16.53%when compared with the Con group(P<0.05).At the age of 42 days,compared with the Con group,the serum triglyceride(TG)content of the broilers in groups 0.20%,0.30%,and 0.40%was significantly reduced by 22.50%,17.50%,and 20.00%(P<0.05).the serum albumin(ALB)content was quadratic increased significantly(P<0.05),of which groups 0.30%was significantly increased by 15.74%(P<0.05).(2)At 21 days of age,the content of glutathione(GSH)in the liver of broilers increased linearly(P<0.05),and the group 0.30%was significantly increased by 62.22%as compared with the Con group(P<0.05).At 42 days of age in broilers,compared with the Con group,BLE linearly and quadratically increased the total antioxidant capacity(T-AOC)and catalase(CAT)activity in the liver of broilers.Among them,the CAT activity in groups 0.40%and 0.50%was increased significantly by 11.24%and 24.71%(P<0.05);Except for the group 0.40%,the activities of superoxide dismutase(SOD)in the other BLE groups were increased by 7.65%,11.66%,7.55%,and 12.93%when compared with the Con group(P<0.05);The glutathione peroxidase(GPx)activity and GSH content in the group 0.50%were significantly higher than those in the Con group(P<0.05);In addition,except for the group 0.10%,the malondialdehyde(MDA)content in the liver of the other BLE groups was significantly reduced by 37.57%,30.06%,30.06%,and 26.59%(P<0.05).(3)At 21 days of age,compared with the Con group,the serum GSH content in the group 0.30%was significantly increased(P<0.05).At 42 days of age,the T-AOC,CAT,and GPx activity in the serum were significantly increased linearly and quadratically when compared with the Con group,of which the T-AOC increased by 38.46%and 31.45%in the groups 0.40%and 0.50%(P<0.05);the CAT activity in the groups 0.20%,0.30%,and 0.50%was increased by 37.52%,46.40%,and 58.04%,respectively(P<0.05);the GPx activity with BLE supplementation was increased by 10.99%,23.78%,21.55%,10.57%and 9.46%,respectively(P<0.05).Part three was conducted to investigate the effect of dietary supplementation with different doses of BLE on breast meat quality and meat oxidative stability in broiler chickens.The experiment design is similar with part 1.Results:(1)Compared with the Con group,BLE supplementation linear significantly reduced the 24 h drip loss,of which the groups 0.3%and 0.40%was decreased by 0.37%and 0.89%(P<0.05).In addition,the pH 45min in groups 0.30%and 0.40%was significantly increased when compared with Con group(P<0.05).BLE supplementation linear significantly reduced the shearing force of the breast,in which the groups 0.10%,0.20%,and 0.30%were 25.67%,31.66%,and 34.61%lower than Con group,respectively(P<0.05).(2)During the 12 days of storage,compared with Con,except for group 0.30%,the other BLE groups showed higher O2-radical scavenging capacity in day 0 and day 4,the O2-radical scavenging capacity was linear improved with the increased BLE supplementation in day 0 and day 4(P<0.05).Except for group 0.30%in day 0 and groups 0.10%,0.30%in day 4,the OH-radical scavenging capacity in other BLE groups was significantly higher than that in Con group(P<0.05).(3)During the 12 day of storage,group 0.20%in day 4 and group 0.50%in day 8 showed the lowest MDA concentration.In day 0 and day 12,except for group 0.10%,the MDA concentration in other BLE group was significantly lower than that in Con group(P<0.05).In day 12,group 0.30%showed the lowest MDA concentration among all groups.(4)compared with Con group,BLE supplementation linear improved T-AOC activity(P<0.05),among that groups 0.30%,0.40%and 0.50%was significantly higher than Con group.The SOD activity of the breast in group 0.10%was significantly increased by 6.14%as compared with the Con group(P<0.05).The GPx activity of the breast was linear significantly increased(P<0.05),and the GPx activity in group 0.50%was significantly increased by 13.53%as compared with Con group(P<0.05).(5)Compared with Con,the Nrf2 mRNA expression in groups 0.30%,0.40%and 0.50%was significantly improved(P<0.05).The GPx and GST mRNA expression in group 0.40%and 0.50%was significantly higher than Con(P<0.05),BLE supplementatin showed no influence on SOD and CAT mRNA expression(P>0.05).Part four was based on the above experiment,after obtaining a suitable BLE dosage of 0.30%,a high dose of BLE was added to the diet to study the tolerance of broilers for BLE.A total of 320 one day old AA broilers with similar body weight were selected and divided into 4 groups,with 8 replicate each,and a replicate containing 10 broilers.A control(Con)group was fed with basal diet,and the other five groups were supplemented with 0.30%,1.50%and 3.00%BLE into basal diet,respectively.A total of 35 day experimental period were divided into start phase(1-21 d)and grower phase(22-35 d).Results:(1)In the start phase,compared with Con group,high dosage BLE supplementation without significant influence on ADFI,ADG and F/G in broilers(P>0.05).In the grower phase,compared with Con group,the addition of high-dose BLE significantly increased ADFI and ADG in broilers by 18.41%,14.31%,14.49%,and 17.61%,11.80%,11.93%(P<0.05);During the whole period,BLE had no significant effect on ADFI,ADG and F/G(P>0.05).(2)The addition of high-dose BLE without influence on organ index as compared with Con(P>0.05).(3)At the age of 21 days,compared with Con group,the PLT in groups 1.50%and 3.00%was significantly decreased(P<0.05),but MPV was significantly increased(P<0.05).The addition of highdose BLE without influence on hematological parameters in grower phase(P>0.05).(4)At the age of 21 day,compared with Con,The addition of high-dose BLE significantly decreased TC content by 16.24%、16.88%and 16.24%(P<0.05),And the TG content in groups 0.30%and 1.50%was significantly lower than the Con group by 46.00%and 36.00%(P<0.05);The serum ALB content in groups 0.30%and 3.00%were significantly increased by 17.63%and 18.37%as compared with Con group(P<0.05).At the age of 35 days,compared with the Con group,the ALB in the groups 0.30%and 3.00%was significantly increased by 18.12%and 19.31%(P<0.05);the GLU content in groups 1.50%and 3.00%was significantly increased by 14.59%and 19.08%(P<0.05).(5)High dosage BLE supplementation without influence on heart,liver,spleen,pancreas,thymus,duodenum,jejunum structural and pathological effect.In conclusion,the results of this study found that BLE supplementation in the basal diet can promote the growth of broilers,improve feed intake and gain weight.When used for growth promotion purposes,it is recommended to add 0.20%to the basal diet;BLE supplementation can impro ve the antioxidant status of broilers,improve the meat quality of broilers,and extend the shelf-life.When used for antioxidant purposes,it is recommended to add 0.30%to the basal diet;Broiler chickens have a good tolerance to BLE supplementation,which is still safe when the added dose of BLE is up to 3.00%. |
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