Evaluation of spent mushroom (Flamulina velutipes) substrate silage-based diets on the growth performance, rumen fermentation, and methane emission in Holstein steers

• Main Authors: K.Teepalak Rangubhet, 明亮
• Other Authors: Hsin-I Chiang
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/12789325443567882444

博士 === 國立中興大學 === 動物科學系所 === 105 === Direct modification of rumen microbial fermentation could provide universal and cost-effective solutions to reduce methane emissions from ruminant livestock. In this study, nutritive and bioactive values of sawdust-based spent mushroom (golden needle mushroom, Flammulina velutipes) substrate (SMS)-based silage were evaluated and effects of SMS silage-based diet on the growth performance, rumen fermentation and enteric methane emission in Holstein steers were investigated. Spent mushroom substrate and whole crop corn were ensiled for 60 days with or without urea in four recipes as follows: High SMS content without urea (90% SMS and 10% whole crop corn); High SMS content with urea (90% SMS, 1% urea and 9% whole crop corn); Low SMS content without urea (80% SMS and 20% whole crop corn); Low SMS content with urea (80% SMS, 1% urea and 19% whole crop corn) on dry matter (DM) basis. There was improvement on nutritive values in SMS-silage supplemented with urea. Low SMS content with 20% whole crop corn could favor the fermentation of silage. The maximum activity of laccase, lignin peroxidase and manganese peroxidase was found in High-SMS with 1% urea (20.8, 2545, 182 U/L, respectively) throughout the 60 days of fermentation period. Treatment diets that contained high SMS-based silage had higher range of total phenol and tannin (9.63-9.89, 1.96-2.03 mg of GAE/g, respectively) than the low SMS-based silage (9.02-9.22, 1.81-1.89 mg of GAE/g, respectively). SMS level and urea supplementation affected (P < 0.05) the cumulative gas production. High SMS contained in silage without urea could reduce (P < 0.05) gas production. Five dietary treatments were prepared as follows: 1) a control diet made-up of 50% concentrate and 50% bermuda hay (Cynodon dectylon), and 2) four diets formulated by replacing 40% of the bermuda hay in the control diet with the four SMS-based silages described above. Five Holstein steers (mean BW 542 ± 72 kg) were assigned to a 5 × 5 Latin square design and offered the five dietary treatments. The results demonstrated that the digestibility of all nutrients in SMS silage-based diets did not differ from the control diet but there were significantly decreased (P < 0.01) on feed conversion ratio in Holstein steers fed SMS-silage based diets. Nitrogen balance tended to be increased (P = 0.06) in animals fed SMS silage which contained 1% urea. Energy loss as methane energy was reduced (P < 0.05) in animal fed SMS silage-based diet. Holstein steers fed with SMS silage-based diets showed blood characteristics within the normal range as the steers fed control diet. Moreover, results of the rumen fermentation revealed that Holstein steers fed diets containing SMS-based silages had lower total protozoa population (3.75 × 105/mL vs. 6.09 × 105/mL), rumen acetate (55.43 mM/L vs. 57.61 mM/L) and methane emission (211 g/day vs. 252 g/day) (P < 0.05) than Holstein steers fed control diet. When comparing the inclusion levels of SMS-based silages in the diets, cattle fed diets with lower levels of SMS-based silages (80% SMS) had higher acetate contents (56.61 mM/L vs. 54.25), protozoa population (3.92 × 105/mL vs. 2.84 × 105/mL) and methane emission (226 g/day vs. 196 g/day) than animal fed diets with higher levels of SMS-based silage (90% SMS). The study revealed that spent Flamulina velutipes substrate silage can be used as forage source in Holstein steers which shows no significant effect on animal health. Feeding steers SMS-based silage can significantly elevate the balance of energy, hence increase body weight gain as well. This work also supports methane mitigating strategies based on reduction of rumen protozoa populations, and the inhibition of methanogenesis in the rumen probably through the presence of phenolic compounds. The study thus unveiled a novel migration strategy for reducing greenhouse gas production in ruminants using agro-industrial by-products. It is also a possible strategy to replace 20% bermuda hay (DM basis) in rations of Holstein steers to reduce feed cost up to 40 NTD/kg ADG.