| The aim of this study was to investigate the effects of dietary digestible fiber(dF,hemicelluloses + pectin)/starch(S)on pellet quality,growth performance,digestive physiology and cecal microflora composition of Angora rabbits.A single factor completely randomized design was used in this test.Five isoenergetic and isoproteic diets with increasing dF/S of 0.59,0.66,0.71,1.05,and 1.44 were formulated and pelleted.The pellet quality was determined.At the same time,one hundred and twenty female Angora rabbits at 83 days old of age with similar average live body weight of(2.19 ± 0.07)kg were randomly divided into 5groups,each with 4 replicates and 6 rabbits in each replicate,and were fed with the above-mentioned 5 different dF/S diets.The pretest lasted for 1 week and the test lasted for 40 days.After the feeding test,each replicate selected one rabbit for slaughter sampling to determine relevant indicators.Cecal contents were colleted.The high-throughput sequencing and q PCR technology were used to investigated.the structure and the number of bacteria in the cecal microflora of Angora rabbits.The results were as follows:(1)Dietary dF/S had a significant effect on all variables of the pellet quality(P<0.05).All the particle pelleting characteristics showed a significant linear relationship with dietary dF/S(P<0.05).The larger the dF/S(1.44),the longer the particles,the lower the powder rate,the higher the durability,and the higher the hardness.Among them,dietary dF/S had quadratic effects on bulk density(P<0.001)and hardness(P<0.05).When the dietary dF/S was 0.67,the bulk density of the pellet reached the highest;when dF/S was 1.53,the pellet hardness was the highest.(2)Dietary dF/S had a significant difference in the average daily gain(ADG),average daily feed intake(ADFI),and feed-to-weight ratio(F/G)of the Angora rabbits(P<0.05),but had no significant difference in the Angora rabbits’ death rate(P>0.05).The Angora rabbit with a dF/S ratio of 0.59 had the highest ADG and with a dF/S ratio of 0.74 had the lowest F/G.There was no significant effects of dietary dF/S on the wool yield and fineness of fluff(P>0.05);however,the effect on length of villus was significant(P<0.05).(3)Dietary dF/S had no significant effects on the relative length and weight of stomach,duodenum,jejunum,cecum and colo-rectum(P>0.05).Differences in villus height,cryptdepth,and V/C ratio were not observed in each group(P>0.05),the longest hair of the 0.66 group of Angora rabbits developed.Dietary dF/S had a significant effect on pepsin and duodenal trypsin activity(P<0.05),and had no significant effect on jejunal trypsin activity(P>0.05).The greater the dietary dF/S,the higher the duodenal trypsin activity.(4)The predominant cecal colonies of rabbits in the different dietary dF/S groups were basically the similar(P>0.05).The dominant bacteria phylum in the rabbits were mainly Firmicutes(59.14%),Bacteroidetes(21.38%),Verrucomicrobia(3.47%),and etc;the dominant bacteria genus were mainly Ruminococcus,Bacteroides,Akkermansia,and etc.The Chao 1 value in the high dietary dF/S group was higher than that in other groups(P<0.05),but no effects on cecal microflora index of Simpson and Shannon(P>0.05).The effects of dietary dF/S on total bacterial count and lactic acid bacteria count were significant(P<0.05),but no effects on counts of cecal Escherichia coli,Clostridium perfringens,and Bifidobacterium.In the meantime,there was a significant linear relationship between the count of Escherichia coli and dietary dF/S,the number of total bacteria and lactic acid bacteria had a significant quadratic relationship with dietary dF/S(P<0.05).In summary,the most appropriate dF/S was 1.44(dF 22.95% DM,S 15.98%DM)for pellet quality,and it did not affect the wool yield,which were caused by changing the structure of Angora rabbit cecal microflora,improving the intestinal development.In summary,under the conditions of this experiment,improving the diet dF/S is beneficial to improve the processing quality and digestion ability of Angora rabbit,without affecting the hair production and gastrointestinal growth,and cecal flora is stable,so the recommended optimal diet dF/S is 1.44(dF is 22.95% DM,S is 15.98% DM). |
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