Effects Of Rosemary And Bacillus Natto On Growth Performance, Meat Quality, Antioxidant Capacity, Immune Function And Intestinal Flora Of Broilers

The aim of this experiment was to investigate the effects of adding rosemary extract and Bacillus subtilis in diets on growth performance,meat quality,antioxidant capacity and immune function as well as intestinal flora of broiler chickens.By exploring the relationship between rosemary and Bacillus subtilis and the physiological characteristics and microbiota of broiler chickens,we provide a basis for the application of rosemary and Bacillus subtilis in poultry feed.In this experiment,360 1-day-old Cobb broilers of similar body weight were randomly divided into 4 groups,and the control group was fed the basal diet and the experimental groups I,II and III were supplemented with 200 mg/kg rosemary,300mg/kg Bacillus Natto and 200 mg/kg rosemary + 300 mg/kg Bacillus Natto,respectively.Samples were collected at 21 days of age and 42 days of age.The test part consisted of part I to part III.In the first part,the effects of Rosemary and Bacillus Natto on growth performance and meat quality of broilers.The results showed that(1)from 1 to 21 d,there was no significant difference in each index of production performance in each group(P>0.05).from 22 to 42 d,ADG was significantly higher in each test group compared with the control group,and test group II was the highest value in each group(P<0.05).The mean daily gain(ADG)was significantly higher(P<0.05)in test groups I and III compared with the rest of the groups from 1 to 42 d.The mean daily gain(ADG)was significantly higher(P<0.05)in test groups I and II compared with the rest of the groups.The control group had a significantly higher material-to-weight ratio,which was the highest value in all groups(P<0.05).(2)The yellowness(b*)value of each test group was significantly lower than that of the control group,and the test group II was the lowest among all groups(P<0.05).Compared with the control group,the steaming loss was significantly lower in test group Ⅲ(P<0.05).The shear force was significantly lower in the test group compared to the control group(P<0.05).Both rosemary and Bacillus Natto increased growth performance and improved meat quality,with rosemary having the best effect.In the second part,the effects of rosemary and Bacillus Natto on antioxidant capacity and immune function of broilers.The results showed that,compared with the control group,(1)GSH-PX activity was significantly higher by 31.50%(P<0.05)in the test III group at 21 days of age.The MDA content in test group III was significantly reduced by 16.58%(P<0.05)compared to the control group,which was again significantly lower(P<0.05)than test groups I and II.At 42 days of age,GSHPX activity was significantly higher(P<0.05)and MDA was significantly lower(P<0.05)in test group III compared to test group I(P<0.05);(2)At 21 days of age,Ig A was significantly higher in each test group compared with the control group(P<0.05).Ig M was significantly higher in each test group than in the control group(P<0.05),and was significantly higher in test groups II and III than in test group I(P<0.05).42 d,Ig A was significantly higher in each test group compared with the control group(P<0.05),and was significantly higher in test group III than in test group I(P<0.05).group was significantly higher than the control group(P<0.05),and the test group was significantly higher than the test group(P<0.05);(3)At 21 days of age,s Ig A was significantly higher in test group III compared with the control group(P<0.05).IL-6 was significantly decreased in test group II compared with the rest of the groups(P<0.05).TNF-α was significantly lower(P<0.05)in test group I compared with the rest of the groups.42 d,IL-1β was significantly lower(P<0.05)in test group II.The results showed that the addition of Rosemary and Bacillus Natto alone or in combination significantly improved the immune function and antioxidant capacity of broiler chickens.In the third part,the effects of rosemary and Bacillus Natto on the cecum microorganisms of broiler chickens.The contents of the cecum were selected at 42 days of age for flora determination.The results of intestinal microorganisms showed that: further analysis of the effects of Rosemary and Bacillus Natto on the intestinal microbial composition of broiler chickens showed that:(1)Alpha and Beta diversity analysis,test I group significantly increased the Shannon index(P< 0.05),test I group significantly decreased the simpson index(P< 0.05).According to the Bray-Curtis inter-sample distance algorithm analysis,there were significant differences in the diversity of cecum flora between the control and treated groups,and the microorganisms in the same group had significant clustering.(2)Analysis of differences between groups of cecum microbiota: At the phylum level,other phyla such as Firmicutes,Bacteroidota,Actinobaceteriota and Campilobacterota were composed,and the phylum Bacteroidota differed significantly between groups.The relative abundance of Campylobacter phylum was reduced in group I and group III(P<0.05).The relative abundance of Campylobacter phylum in test group III was significantly lower than that in other groups(P<0.05).At the genus level,the cecum flora of broilers in the control and test groups consisted of Faecalibacterium,Alistipes,Bacteroides,unclassified f_norank_o_Clostridia_UCG-014(norank_f_norank_o_)and Clostridium.Clostridia-UCG-014)and other genera,and the genus Bacteroides was significantly higher in test group II than in other groups(P<0.05).The abundance of Faecalibacterium in test group Ⅲ was significantly higher than that of the control group and test Ⅰ and Ⅱ groups,and the abundance of Ruminococcus_torques_group in test group Ⅲ was significantly lower than that of the control group and test Ⅰ and Ⅱgroups(P<0.05).Thus,the addition of rosemary and Bacillus Natto in the diet could improve the antioxidant capacity and immune function of broilers,reduce the abundance of harmful bacteria,increase the proportion of beneficial bacteria and improve the composition of intestinal flora.