| In order to improve the feeding nutritional value of rapeseed meal,single factor test and orthogonal test were used to optimize the technical parameters of solid state fermentation of type 95 rapeseed meal and low temperature rapeseed meal.Metabolic experiment and feeding experiment were used to evaluate the nutritional value of two kinds of fermented rapeseed meal,which included the following three parts:Experiment 1: Optimization of fermentation technical parameters of two kinds of rapeseed mealIn this experiment,taking the content of anti-nutritional factors as the monitoring index,the solid-state fermentation parameters of rapeseed meal(type 95)and low temperature rapeseed meal were optimized by single bacteria solid fermentation,mixed bacteria solid fermentation and orthogonal test.The results showed that the optimal fermentation parameters of type 95 rapeseed meal were as follows: Aspergillus flavorus:Saccharomyces cerevisiae SC17-1: Bacillus subtilis BS15-3 strain ratio 3:4:2,fermentation temperature 30°C,fermentation time 4 days.The optimal fermentation parameters of low temperature rapeseed meal were as follows:(Aspergillus Niger +Aspergillus oryzae): Lactobacillus plantarum LP17-1:BS15-3:SC17-1=6:2:2:4,fermentation temperature 37°C,fermentation time 10 days.Experiment 2: Evaluation of Type 95 rapeseed meal produced by solid State fermentation at High temperature1.Metabolic experiment of fermented rapeseed mealOne hundred healthy 1-day-old Arbor Acres(AA)broilers were selected and fed with corn-soybean meal basal diet before the experiment.At the age of 21 days,90 healthy broilers with similar weight were selected from 100 broilers and randomly divided into 3 groups with 6 replicates in each group and 5 broilers in each group.They were fed corn-soybean meal basal diet,type 95 rapeseed meal at high temperature to be tested diet(30% rapeseed meal to be tested diet),and type 95 fermented rapeseed meal at high temperature to be tested diet(30% fermented rapeseed meal to be tested diet),and all diets were supplemented with 0.4% titanium dioxide as exogenous indicator.The results showed that the apparent metabolic energy(AME)and nitrogen corrected apparent metabolic energy(AMEn)of type 95 rapeseed meal at high temperature were 7.44 and 7.40 MJ/kg,respectively,and that of fermented rapeseed meal were 7.27 and 7.23 MJ/kg,respectively.There were no statistical differences in AME and AMEn between rapeseed meal and fermented rapeseed meal(P>0.05).2.Broiler feeding experiment of fermented rapeseed mealA total of 252 1-day-old healthy AA broilers with similar body weight were randomly divided into 6 groups with 6 replicates in each group and 7 broilers in each group.The dietary treatment groups were as follows: corn-soybean meal diet,adding10% level of 95 type rapeseed meal,adding 10% level of dry fermented 95 type rapeseed meal,adding 10% level of wet fermented 95 type rapeseed meal,adding 15%level of dry fermented 95 type rapeseed meal,adding 15% level of wet fermented 95 type rapeseed meal,the nutritional level of each diet was consistent.The results showed that:(1)During the whole feeding period,the average daily gain(ADG)and average daily feed intake(ADFI)of broilers fed with 10% fermented rapeseed meal were not significantly different from those fed with 10% rapeseed meal.(2)At 1 to 21 days of age,the organ index of broilers in 10% or fermented rapeseed meal group had no difference compared with the control group(P>0.05).At 22 to 42 days of age,adding 10% rapeseed meal and 10% fermented rapeseed meal increased thymus index of broilers(P<0.05).(3)Adding 10% wet fermented rapeseed meal significantly increased the villus width(VW)and villus surface area(VSA)of jejunum(P<0.05).(4)Compared with 10% rapeseed meal group,adding 10% wet fermented rapeseed meal significantly decreased the levels of acetic acid and butyric acid in cecum of 42-day broilers(P<0.05).(5)Compared with the basal diet group,the content of polyunsaturated fatty acids(PUFA)in breast muscle and leg muscle was increased in fermented rapeseed meal group(P<0.05).Experiment 3: Evaluation on feeding effect of solid-state fermentation products of rapeseed meal prepared at low temperature3×2 factor experimental design,factor 1: injection of lipopolysaccharide(LPS)or normal saline solution;factor 2: 9% low-temperature rapeseed meal and 9%fermentation low-temperature rapeseed meal.A total of 210 healthy 1-day-old broilers with similar body weigh were randomly divided into 6 groups with 5 replicates in each group and 7 broilers in each group.The experiment was divided into three stages: 1)1-14 days old in the feeding period;2)15-21 days old in the LPS stress period;3)22-42 days old in the later stage of feeding.On the morning of the 16 th,18th and 20 th day of the experiment,500μg/kg BW LPS solution was injected intraperitoneally to the broilers in the LPS group,and the same dose of saline solution was injected into the broilers in the control group.The results showed as follows:(1)Growth performance: Compared with saline group,the BW of 22-day-old and 42-day-old broilers in LPS stimulation group decreased(P<0.05),and ADG of broilers in 1 to 42 days of age was decreased(P<0.05).(2)Organ index:(1)Compared with rapeseed meal group,liver index of broilers at 21 days of age in fermented rapeseed group was significantly decreased(P<0.05);(2)Compared with normal saline group,spleen index of broilers at 21 days of age was significantly increased in LPS stimulation group(P<0.05).(3)Serum biochemistry index:(1)Compared with rapeseed meal group,serum AST and ALT decreased significantly in 42-day-old broilers in fermented rapeseed meal group(P<0.05);(2)Compared with normal saline group,serum AST of broilers at 42 days of age in LPS stimulation group was significantly increased(P<0.05).(4)Serum immunity index: Adding fermented rapeseed meal or injecting LPS could significantly increase the levels of Ig A,Ig G and Ig M in serum and decrease the level of IL-6 in serum of broilers(P<0.05).(5)Intestinal microorganisms: Adding fermented rapeseed meal or injecting LPS could significantly reduce the contents of Escherichia coli and Salmonella in cecum digesta of broilers(P<0.05).(6)Intestinal metabolites:(1)Compared with rapeseed meal group,propionic acid and isobutyric acid in cecum of 21-day-old broilers in fermented rapeseed meal group increased significantly(P<0.05).(2)Compared with normal saline group,the levels of valeric acid,isobutyric acid and isovaleric acid in cecum of broilers at 42 days of age in LPS group were significantly decreased(P<0.05).(7)Jejunum morphological indexes:(1)Compared with rapeseed group,fermented rapeseed meal could significantly decrease Jejunum CD of broilers at 42 days of age(P<0.05);(2)Compared with normal saline group,jejunum CD of broilers at 42 days of age was significantly increased in LPS stimulation group(P<0.05).In summary,solid-state fermented could improve the comprehensive feeding value of type 95 high-temperature rapeseed meal,and adding low-temperature fermented rapeseed meal to diet could alleviate the the physiological function damage of broilers caused by LPS stress. |
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