Study on the feeding value of brewer's by-products for ruminants

三重大学大学院生物資源学研究科博士後期課程The demand of grains has been increasing in the global scale mainly in ethanol production from starchy grain, human food in China and developing countries. The renewed interest in using domestically produced nutrient rich feedstuffs for livestock production is partially a consequence of the bovine spongiform encephalopathy (BSE) crisis, the irregular availability of concentrate feeds and their high cost, and feed scarcity due to change the global environment. Therefore locally available food by-products are becoming growing interest to farmers for their cattle feeding. Therefore, this study was conducted aiming at increasing knowledge on using locally available food industrial by-products (SSC and VBC). Using NaCl, (Contained in SSC) even 2% of medium, ffectively inhibited the growth of LAB which is generally involved in silage fermentation. Among 4 types (Lactobacillus plantarum, Lactococcus lactis, Leuconostoc mesenderoides and Pediococcus acidilictici) of LAB species L. plantarum was more sensitive to NaCl as compared to other three species. The growth of Clostridium butyricun was also positive inhibited in the medium and the growth was became almost half when 2% NaCl was added in the medium. The yeasts growth was inhibited by the addition of NaCl in the medium but yeasts species were more resistant to NaCl as compared to LAB and butyric acid bacteria. From the result of this study, it is concluded that C. butyricum was more sensitive to NaCl in the medium as compared to other microorganisms used in this study and also related to the silage fermentation. The addition of pellet from SSC and VBC in TMR silage lowered the lactic acid and butyric acid production, decreased LAB number for short time of fermentation. The pellet addition in TMR silage was negative effect on the total number of yeasts. Increasing level of pellet of SSC decreased lactic acid concentration, and no or low butyric acid concentration after short time of fermentation. In this study, research has been carried out for diet evaluation in vitro gas production, rumen fermentation, and, DM and OM degradability. The in vitro gas and VFA production, and, DM and OM degradability were higher in concentrate than in SSC and VBC when incubated as a sole diet. Whereas, in vitro gas and VFA production, and, DM and OM degradability were not different in the TMR silage-based diet when 15% (of total diet as DM basis) concentrate was substituted with SSC and VBC. Research was also carried out with in vivo digestibility and rumen fermentation where the diet prepared as same as in vitro experiment. The digestibility of DM and CP in the rumen, post rumen and total tract, rumen pH, VFA and NH3-N concentration and blood metabolic profiles were similar in growing steers fed TMR silage-based diet upplemented with SSC and VBC. From the present research, the following conclusions were drawn: 1) 2% as FM basis of the medium NaCl was ffectively controlled the growth dynamics of homo- and hetero-fermentative LAB, butyric acid bacteria and yeasts species in the medium. 2) In the fermentation of TMR silage, 20% of FM basis of pellet of SSC was more effective to enhance the fermentation in context of low lactic acid and no butyric acid concentration. 3) In the ngredient evaluation, concentrate was better ingredient as compared to SSC and VBC. 4) Finally in the digestibility trial or in the diet evaluation, SSC and VBC have the similar value as concentrate in TMR silage-based diet and would be used as substitute/ alternative feed resources for ruminants at 15% on a DM basis. The following recommendations are suggested; a) to examine the growth of homo- and hetero-fermentative LAB and butyric acid bacteria in lower than 2% concentrated NaCl medium. b) Conduction of comparison of SSC and VBC with other brewer’s by-product available in Japan or other developing countries as an ingredient of TMR fermentation. c) Research is imperative to investigate the effects secondary metabolites of SSC on microbial growth in vitro incubation and during silage fermentation. d) In vivo studies to investigate the effect of SSC and VBC on growth performance and fattening, and, milk production in cattle.