The Evaluation Of Nutritional Value Of Arundo Donax And Its Application To Mutton Sheep

In this study,in order to alleviate the shortage of grass resources,Arundo donax was used as the research material to evaluate its nutritional value,and based on this,the feeding and slaughtering experiments of mutton sheep were carried out.The nutritional value of Arundo donax was evaluated to provide basic data for the development of new forage grass.Exp.1:The nutrient contents of different parts（stem,leaf,whole grass）and different heights（1m,1.2 m,1.4 m,1.6 m,1.8 m）of Reed were determined by chemical analysis.The results showed that leaves were superior than stems of Arundo donax for feeding;The nutritional value in Arundo donax was the highest at the height of 1.2 to 1.4 m;Ultrasonic extraction was used to extract from Arundo donax.Factors including ultrasonic power,ultrasonic time,ethanol concentration,ultrasonic temperature,solid-liquid ratio,pH value of solvent were investigated.The method of response surface analysis with four factors and three levels was adopted to optimize the extraction process.The optimum technological circumstances were resolved as follows:ultrasonic power 600 W,ultrasonic time 50 min,ethanol concentration 60%,ultrasonic temperature 50℃,solid-liquid ratio 40 mL·g^-1,and pH 5.The gramine yield was 1.00%.The content of Arundo donax in the leaf was much higher than that in the stem.The antioxidant activity of grammine from Arundo donax is 0.465mmol/g by FRAP,and the degree of inhibition isStaphylococcus aureus>E.Coli>Salmonella by using 96-well microtiter plates.Exp.2:3 adults Holstein cows with permanent rumen fistula were selected,whose body weight was（550±25）kg.The dynamic degradation rate of nutritional components in rumen was evaluated by nylon belt method.The results showed that the effective degration rate of crude protein reached 42.35%,the effective degration rate of neutral washing fiber reached 27.01%,and the effective degration rate of acidic washing fiber reached 21.54%,when the rumen velocity k=0.05/h.From the perspective of the content and degradation rate of various nutritional components,the nutritional value of 2.5 m Arundo donax is lower than 1.8 m.Exp.3:The whole Arundo donax with the height of 0.4 m was harvested for silage experiment,three bags were randomly selected at the silage time of 7,15,23,30,45 and 60 days,and the fermentation quality was analyzed in laboratory.Dynamic study on the changes of silage nutrition and fermentation quality.MRS media were used to screen microbial species from silage Arundo donax for 30 days,under anaerobic culture conditions.The species and genera of the screened microorganisms were identified.The results showed that:during silage,the content of CP and ash increased,and the content of DM,NDF and ADF declined with silage days,the pH significantly declined,the content of NH₃-N was the highest when the silage time was 30 d,and the content of WSC decreased gradually.It can be concluded that Arundo donax can get a good quality after 30-day fermentation.With the increase of silage time,the content of gramine increased at first and then decreased.The content of gramine was the highest at the 30th day of silage.A total of 3 strains were isolated on MRS media,under anaerobic,at 37℃.After morphological analysis and conservative sequence alignment,2 strains were identified as L.plantarum;1 strains were identified as Pediococcus acidilactici.Exp.4:Three groups were set up in the study,Arundo donax,silage alfalfa and corn stalk were used as single roughage source in each group respectively,then a series of experiments were carried ou as sheep feeding and slaughtering.The results showed that:compared with corn stalk,the growth performance of mutton sheep feeding with Arundo donax was better.With the feeding time longer,the ADG and F:G of lamb in the Arundo donax group had no significant difference with that of silage alfalfa,and the effect of gaining the weight of mutton sheep was similar.So Arundo donax can be used as a substitute for silage alfalfa.The carcass weight of lamb was significantly increased and the muscle quality was improved by replacing corn straw with Arundo donax.Arundo donax can increase the content of glutamic acid and improve the flavor of muscle.Compared with silage alfalfa,Arundo donax decreased the antioxidant capacity of lamb significantly and was not suitable to replace silage alfalfa completely.In each group,the similarity of rumen microflora was low,but the dominant flora was the same at the level of phylum and genus.Compared with silage alfalfa and corn straw,there was no significant effect of Arundo donax on Rumen microflora composition and richness of lamb.The results showed that Arundo donax had high nutritional value and was a new type of forage grass with great development potential.