| The world population projected to grow at an alarming rate.Meanwhile,the number of people with better economic standard has been increasing.As a general trend,there is an increasing demand for livestock products with increasing living standard.This demands for higher quantity and quality production of livestock products.However,the main cost of livestock production accounts for feed costs.Crop residues are the most abundant resources.They are byproducts of the grain crop production,which includes stover,straw,haulms,and other parts of the crop other than the grain.The importance of crop residues may differ based on the production system.Crop residues are critically important as animal feed in the integrated crop-livestock production system.However,there is still competition for different uses,such as mulching,fuel fire and house construction.There is also a huge demand for crop residue in particular and lignocellulose biomass in general from the biofuel sector.There is also a growing interest to use crop residues for production of some of the most useful products and byproducts,such as prebiotics,industrial chemicals,and antioxidants.Crop residues make it most important because ruminant animals can hardly survive without it.The majority portion of ruminant ration should comprise crop residues or other roughage feed source for the proper function of the rumen ecosystem.Among crop residues,corn stover is the most important feed,which has been used as a main source of animal feed.Its level of production depends on different factors and differ from region to region and from country to country.The leading corn or corn producing countries are the United States of America and China.Corn stover is a byproduct of the grain;hence,its nutritional quality is very low,since it is harvested after its full maturity.All plants are composed of three structural components.These are cellulose,hemicellulose and lignin.The proportion of these components depends on different factors but stage of growth or plant maturity is one of the most important factor.One of the most important nutrient,which is limited in corn stover,is protein or any nitrogen source component.The nitrogen content of corn stover cannot support the rumen microfuana to properly function and enhance the ruminant animal productivity or serve as a bypass protein.Moreover,the structural portion of the crop residues,which is secondary plant cell walls,cannot be completely disintegrated even with rumen microbial enzymes.On top of this,the presence of chemicals with antinutritional effects,such as phenolic acids,complicates the problem.To improve this several crop residue improvement methods have been employed in different sectors.The biofuel sector has also been using lignocellulose biomass pretreatment methods to improve the saccharafication,delignification and hydrolysis of the biomass for better biofuel yield,quality and profitability.Several methods has also been used for determination of structural,nutritional and anti-nutritional composition.However,so far little has been done to explore the experiences of crop residue improvement methods to utilize for improving crop residues,as animal feed.Secondly,although a lot has been done to associate simple nutritional composition determination methods with sophisticated once;cellulose crystallinity Index(CrI)has not yet been investigated to be used as an indirect method of crop residues nutritional or anti nutritional composition determination indicator.The objectives of this piece of work is therefore to explore currently implemented lignocellulose pretreatment methods and institutional arrangements,which can be applied for livestock production.Secondly,to associate determination of cellulose crystallinity Index(CrI),which is relatively simple method with nutritional and anti-nutritional composition using treated corn stover as a means and serve as a basis for further investigation.To draw lessons from the biofuel production sector several research papers were reviewed and consolidated in the form of reviewed research paper.The two main points,which were,explored for deriving the livestock sector,are the enabling environments and technical aspects.The institutional or enabling environments identified include;policy issues,sense of urgency,financial and research focus,and market information dissemination issues.Some of the most important lessons drawn regarding technical aspects includes;the advanced lignocellulose pretreatment technologies.Although,most pretreatment technologies use catalysts and chemicals,which can be toxic to animals,there are a lot others which are safe and which can be applied to improve nutritional composition.Among which Liquid Hot Water(LHW)and Ammonia Fiber Explosion(AFEX)can be the most pertinent methods which can be used for crop residue treatment,given it is economically feasible.In the second research,corn stover was treated with calcium hydroxide(CTCS),urea-calcium hydroxide(UCTCS),steam explosion(STCS)and ammonia treatment(ATCS)methods and untreated corn stover(UCS)as a control.All treatments were incubated in vitro for 72 hrs using rumen fluid obtained from dairy cows.Treatments were arranged in Completely Randomized Design(CRD and replicated three times.Cellulose crystallinity using X-ray defractrometry calculated as crystallinity Index(CrI),phenolic acids of all feed treatment before and after incubation and chemical composition before incubation was analyzed for chemical composition,digestibility and metabolizability of phenolic acids and relationships among the three using Pearson correlation and Principal Component Analysis.The highest(P<0.001)CP was obtained for UCTCS and STCS,respectively.Whereas the highest(p<0.001)NDFom and hemicellulose were recorded for ATCS,with the lowest being for STCS.The highest and lowest(p<0.05)lignin contents were recorded for STCS and CTCS,respectively.Highest and lowest for FAest(p<0.01)and PCAest(p<0.001),respectively was recorded for both UCS and UCTCS.However,highest FAeth(p<0.001)and PCAeth(p<0.001)observed for UCS and STCS,respectively and lowest for CTCS,and UCS and CTCS,respectively.Crystallinity index was nonsignificant but significantly(p<0.05)different before and after in vitro incubation,respectively.The highest FAest digestibility(p<0.05)and FAeth(p>0.05)digestibility was recorded for UCTCS.Similarly,PCAest digestibility(p<0.05)and PCAeth digestibility(p<0.01)was higher for UCTCS.However,FAest metabolizability(p<0.01)was highest for UCS and lowest equally for CTCS and ATCS.PCAest metabolizability(p<0.01)was highest and lowest for UCTCS and UCS,respectively.The principal Component Analysis had clearly indicated the clustering of the phenolic acid components in one group but not the structural components,except for CrI,aNDF and ADFom.Interestingly CP,lignin(sa)and ash clustered with the phenolic acid components.Moreover,both the Pearson correlation and Principal Component Analysis assured the negative relationship between the CrI and ester based ferulic acid content.It was also pin pointed that STCS had more or less similar mode of action with UCTCS on nutritional and phenolic acid changes of corn stover.Therefore considering the cost of steam explosion UCTCS is the best pretreatment method.As a general concluding remark,there is unexplored crop residue improvement methods from the biofuel production sector and elsewhere that can be applied for livestock production.Moreover,the global institutional organization for livestock sector(especially for the ruminant livestock)should be reorganized in such a way that semi intensive and smallholder subsistence farmers can benefit in an efficient,environmentally friendly and productive way.It is also empirical to see easily applicable feed resources nutritional and anti-nutritional composition determination methods. |
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