Processing Quality Of Rice Straw Pellet Feed And Its Effect On In Vitro Fermentation Of Sheep

Straw is one of the most productive crop straws in China,which has a lot of nutrients such as cellulose,hemicellulose,lignin and minerals.But its protein and crude fat content is very low.After processing and granulation,its physical and chemical properties and palatability can be improved,and the feed intake and digestibility of animals can be improved.At present,a large number of studies at home and abroad mainly focus on the effect of roughage length on ruminant production performance and rumen fermentation.However,there are few reports on screening processing parameters of ruminant pellet feed and evaluating rumen fermentation characteristics of rice straw pellet feed by in vitro rumen fermentation technology.Therefore,the purpose of this paper is to study the effects of different grain sizes of rice straw and mold hole diameter on the processing of goat pellet feed,as well as the total gas production,hydrogen,methane,dry matter disappearance rate,p H value and ammonia nitrogen concentration in vitro rumen fermentation,so as to provide basic research data for the processing of goat pellet feed.Test 1: the effect of rice straw and mold hole diameter on the processing quality of goat pellet feedA 2 × 3 double factor experimental design was used in the experiment.The hardness,density,molding rate and pulverization rate of goat pellet feed were taken as the evaluation indexes.The grain sizes of straw were 2 mm,3 mm,4 mm,and the diameter of pelletizer mold hole was 4 mm and 6 mm respectively.The results show :that there was no significant effect of rice straw particle size on the pulverization rate,density and hardness of pellet feed(P > 0.05),but significantly affected the molding rate of pellet feed(P < 0.01).With the increase of grain size of rice straw,the pulverization rate first increased and then decreased,while the molding rate increased gradually.The diameter of pelletizer mold hole had a significant effect on the molding rate and pulverization rate of TMR pellet feed(P < 0.01),and significantly affected the particle density(P < 0.05).The molding rate and pulverization rate of pellet feed with diameter of 6 mm were higher than those of 4 mm group.Test 2:The effects of different processing parameters on in vitro fermentation characteristics of goat pellet feedA 2 × 3 double factor experimental design was used to investigate the effects of different processing parameters on the in vitro fermentation characteristics of goat pellet feed.Six groups of pellet feed with different crushing particle size and diameter of pelletizer mold hole were used as the substrate for in vitro fermentation.The gas production,methane production,hydrogen production,dry matter disappearance rate,p H value and NH3-N concentration were investigated by in vitro gas production method The impact of sex.The results show:(1)the particle size of rice straw had a significant effect on the gas production of pellet feed at 12h(P < 0.01)and 24h(P < 0.05).The diameter of die hole had a significant effect on the gas production at 12h(P < 0.05),and had a significant effect on the gas production at 36 h,24h and 48h(P < 0.01).At the same time,there was a significant interaction between the rice straw crushing size and the diameter of the pelletizer mold hole(P < 0.05).(2)the grain size of rice straw had a significant effect on the hydrogen production of goat pellet feed from 12 h and 24 h(P < 0.01),and the diameter of pelletizer mold hole had a significant effect on hydrogen production at different time points(P < 0.01),and the hydrogen production of 6 mm diameter group was significantly higher than that of 4 mm group.(3)There was no significant effect of rice straw crushing size on methane production of pellet feed in vitro(P > 0.05),but the diameter of pelletizer mold hole significantly affected methane production of pellet feed(P < 0.01).(4)During the whole fermentation period,the dry matter loss rate of goat pellet feed ranged from 65.24% to 69.34%.There was no significant effect of rice straw crushing size and pelletizer mold hole diameter on dry matter loss rate of pellet feed(P > 0.05)and no significant interaction(P > 0.05).(5)the particle size of rice straw had significant effect on the concentration of NH3-N in pellet feed(P < 0.05),and the diameter of mould hole in granulator had significant effect on NH3-N concentration of pellet feed(P < 0.01).(6)the particle size of rice straw had a significant effect on the p H value of in vitro fermentation(P < 0.01),but the diameter of the mould hole of the granulator had no significant effect on the p H value(P > 0.05).At the same time,the particle size of the rice straw and the diameter of the mould hole of the granulator affected the p H value of the pellet feed in vitro(P < 0.01).