| PeNDF have measures the physical properties,ability to stimulate ruminants,and retention time in the rumen of fibers.PeNDF further evaluates the value of feed ingredients.Compared with other herbivores such as rabbits and horses,ruminants can digest the fibers in plants as their own energy source more effectively.In the past,the research has focused on the effect of different sorghum ratios,forage cutting length or peNDF content on ruminant breeding,dietary behavior and growth,nutrient utilization,and the quality of dairy milk,there is currently no systematic study on the effects of peNDF on ruminant energy metabolism,methane emissions,and rumen microbial community structure.This experiment was designed as a single factor experiment.Thirty four-month-old Lezhi black goats?rams?were selected and divided into five treatment groups by a completely randomized block design,to research the effect of roughage cutting or pulverizing different degree(cutting 7cm,cutting 4cm,cutting 1cm,passing over 5mm sieve and 1mm sieve,peNDF1.18 content is 33.0%,29.9%,28.1%,26.5%and 24.8%,respectively)on goats growth performance,nutrient digestion,methane emission and energy metabolism when the diet composition was consistent,and high-throughput sequencing technology was used to detect differences in microbial community structure in goat rumen were investigated to investigate the effects of dietary peNDF content on rumen microbes in ruminants.The test pre-feeding period was 14 days,and the trial period was 30days.The results are as follows:?1?Whether the level of peNDF1.18 is high or low,it would reduce the performance and the nutrients apparent digestibility of goats?P<0.05?.In this experiment,the feed peNDF1.18 level was 26.5%?the forage crushed 5mm sieve?,the goat feed intake and ADG reached the maximum,respectively,831g/d,98.5g/d,the nutrients apparent digestibility of the group of 28.1%?when forage cutting 1 cm?was the highest in this test??2?The level of dietary peNDF1.18 was affect the daily methane emissions of goats?P<0.05?,but it had no effect on the ratio of methane energy to gross energy,digestive energy or metabolic energy.And the level of dietary peNDF1.18 significantly affected goat energy metabolism.In this experiment,28.1%of the group?forage cutting 1cm?had the highest ME/GE of 68.7%.?3?Dietary peNDF content had no significant effect on rumen pH,TVFA,propionic acid,butyric acid and ethylene-propylene ratio in goats,but it affected the proportion of rumen acetic acid,ammonia nitrogen and microbial protein in goats?P<0.05?.The content of peNDF1.18 decreased,the proportion of rumen acetic acid increased,and the concentration of microbial protein decreased.?4?With the reducing the level of peNDF1.18 in the diet,the relative abundance of Bacteroides,Prevotella 1,Ruminococcus 2 increased,when the relative abundance of Firmicutes,Ruminococcaceae NK4A214 gut group,Ruminococcaceae UCG-005,Butyrivibrio 2,Clostridium sensu stricto 1,Pirellulaceae was decreased.The bacterial community structure of each treatment was significantly different.The composition of methanogens in 33.0%treatment group was significantly different from the other four groups.?5?Prevotella 1,Bacteroidales,Rikenellaceae RC9 gut group,Muribaculaceae were microorganism with high abundance and closely related to microbial function,which may be the key bacteria to study the function of rumen microbial community.Conclusion:High or low dietary peNDF levels could reduce goat performance,nutrient apparent digestibility and energy metabolism efficiency,but have a weaker effect on rumen fermentation parameters.With the decrease of dietary peNDF level,the relative abundance of Bacteroides and Prevotella 1 increased,and the relative abundance of Firmicutes and Ruminococci decreased.The bacterial community structure of each treatment was significantly different.Under the conditions of this test,the recommended level of peNDF1.18 for goats is between 26.5 and 28.1%. |
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