| Acer truncatum bunge leaves have a comprehensive nutritional value and are rich in flavonoids,chlorogenic acids,polysaccharides,and other active ingredients.As a special economic forest resource,A.truncatum industry has the development prospect of feed and feed additives.The exploitation of A.truncatum leaves resources can increase its economic value before seed-setting and promote the sustainable development of the “Planting and breeding cycle” in A.truncatum industry.In this experiment,the nutritional components of different cutting times,positions,years,green,and withered A.truncatum were studied.Combined with the determination of the optimal dynamic mowing time of A.truncatum,the pretreatment of A.truncatum leaves by bacterial enzyme synergistic fermentation was attempted and the comparison of the nutritional components of A.truncatum before and after fermentation were studied.Finally,the effects of A.truncatum leaves before and after fermentation on performance,egg quality,and blood biochemistry of 70-week-old laying hens were investigated by using the substitution method(replacing bran with 1%,2%,4%,and 8%).It is expected to provide a theoretical basis and data support for the development and utilization of A.truncatum leaves feed resources.Exp.1 Analysis of nutritional characteristics of dynamic mowing A.Truncatum leavesIn this experiment,at different times(AM 08:00,PM 13:00,and PM 18:00),different canopy positions(upper,middle,and lower),different years(1,3,5,8,12 years old),green and withered A.truncatum leaves were collected.The contents of proximate nutrition,precision nutrition,bioactive component,mycotoxin,and anti-nutritional factor were analyzed after the leaves were dried and crushed.The results showed that: 1)The crude protein content in A.truncatum leaves was 9% – 17%,and the crude fiber content was 11% – 18%.2)The crude protein and crude fiber content in the leaves moved at noon was significantly higher than that in the morning and afternoon(P < 0.05),and the nitrogen-free extract content in the leaves moved in the morning was significantly higher than that in noon and afternoon(P < 0.05).3)The crude ash content of leaves in the lower canopy was significantly higher than that in the middle and upper canopy(P < 0.05).4)Compared with green leaves,the contents of crude protein and nitrogen-free extract in defoliation were significantly decreased(P < 0.05),and the contents of some bioactive components,anti-nutritional factors,and mycotoxins were significantly decreased(P < 0.05)in defoliation leaves.5)The contents of crude protein and zearalenone in 5-year-old leaves were significantly higher than those in 3-year and 8-year-old leaves(P < 0.05).With the increase of tree age,the contents of nitrogen-free extract,total phenol,chlorogenic acid,and phytic acid gradually decreased.The results of this experiment showed that the harvest time should be avoided as much as possible in the afternoon,and the nutritional value of the middle and upper leaves of the canopy was slightly better.Compared with green leaves,dead leaves still have some bioactive components and feeding value.Combined with the dynamic changes of leaf nutrients and the effects of harvested leaves on tree growth and development,3-year-old leaves have a higher utilization value before seed setting(1,3,5 years old).Exp.2 Analysis of nutritional characteristics of A.Truncatum leaves by co-fermentation of bacteria and enzymesIn this experiment,A.Truncatum leaves were pretreated by co-fermented with bacteria and enzymes under different moisture,temperature,and substrate conditions(“A.truncatum leaves and corn meal”,“A.truncatum leaves and soybean meal and wheat bran”).The sensory evaluation,microbial count,aerobic stability evaluation,physical structure observation by scanning electron microscope and nutrient composition were analyzed.The results showed that: 1)A.truncatum leaves fermentation bags were swelling for about 12 h after bagging,and the color changed from bright green to yellow-green after fermentation.The fermented leaves have acidity and wine aromas,soft texture,slightly moist.2)The fermentation of the “A.truncatum leaves and corn meal” group could start normally,but it was greatly affected by fermentation temperature and water content.What’s more,the number of yeast and Bacillus subtilis after fermentation was significantly higher than that of “A.truncatum leaves and soybean meal and wheat bran”(P < 0.05).3)Scanning electron microscope(SEM)showed that the fiber structure of A.truncatum leaves became loose and porous after fermentation,and the bacterial residues were visible in the field of vision.After fermentation,the contents of crude fiber,anti-nutritional factors,and mycotoxin were significantly decreased(P < 0.05).The results of this study showed that the co-fermented with bacteria and enzymes of A.truncatum leaves was feasible.The combination mode of “A.truncatum leaves and soybean meal and wheat bran” after fermentation was more stable than that of “A.truncatum leaves and corn meal”.The feeding value of leaves could be improved after fermentation.Exp.3 Evaluation of feeding effect of fermented A.Truncatum leaves on aged laying hensA total of 270 70-week-old healthy Hyline brown laying hens were randomly divided into 9 groups consisting of 6 replicates.The control group was fed a basal diet of the cornsoybean meal,and the experimental groups were fed a diet containing 1%(M1,FM1),2%(M2,FM2),4%(M3,FM3),and 8%(M4,FM4)A.truncatum leaves before and after fermentation,which replaced with bran in an equivalent amount.The pre-test period was 2weeks and the experimental period was 12 weeks.The results showed that: 1)Compared with the control group,the laying rate in M3,M4,and FM4 groups decreased significantly at 1-4weeks(P < 0.05).The laying rate of M4 and FM4 showed a tendency to decrease in the whole period(P=0.073).The laying rate of the M4 group showed a tendency to decrease compared with the control group at 5-8 weeks(P=0.065),while the laying rate of the FM4 group showed no significant difference compared with the control group at 5-8 weeks(P > 0.05).2)In the2 nd week of the experiment,compared with the control group,the egg protein height and Haugh unit of M4,FM3,and FM4 groups were significantly decreased(P < 0.01).In the 6th week of the experiment,the egg yolk color was significantly improved after feeding the A.truncatum leaves before and after fermentation(P < 0.01).3)Meanwhile,the level of total cholesterol and triglyceride in the blood of FM1 and FM2 groups were significantly lower than those of M1 and M2 groups(P < 0.05).The conclusion showed that: feeding the high level of A.truncatum leaves before and after fermentation reduced the laying rate,egg protein height,and Haugh unit,but improved the yolk color of old laying hens.The adverse effects of maple leaf supplementation on the production performance and blood biochemistry of laying hens can be alleviated by fermentation treatment.In all,the A.truncatum defoliation and the leaves before seed setting have a value for forage resources development.The synergistic fermentation of bacterial enzymes could destroy the fiber structure of A.truncatum and degrade mycotoxins and anti-nutritional factors in A.truncatum.The egg yolk color was improved by feeding A.truncatum leaves before and after fermentation.But the laying rate and egg quality of old laying hens were significantly reduced by adding 8% of A.truncatum leaves before and after fermentation.The adverse effects of the high level of A.truncatum leave on production performance and blood biochemistry could be alleviated by fermentation. |
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