Effect of mechanical processing of corn silage on in vitro ruminal fermentation, and in situ bacterial colonization and dry matter degradation

Abstract

. Effect of mechanical processing of corn silage on in vitro ruminal fermentation, and in situ bacterial colonization and dry matter degradation. Can. J. Anim. Sci. 87: 259-267. Rumen fermentation and bacterial colonization of mechanically processed corn silage were evaluated in a series of in vitro and in situ experiments using ruminally cannulated cows. Data from rumen-simulated continuous culture (Rusitec) showed that total VFA concentration was increased (P < 0.001) by feeding processed corn silage, while pH was reduced (P < 0.001) and ammonia nitrogen remained unchanged (P > 0.05). Mechanical processing enhanced the in situ rate and extent of dry matter disappearance for corn stems and kernels, respectively (P < 0.05). It also enhanced in situ, the initial attachment of rumen bacteria responsible for corn digestion, as monitored by real-time PCR. The16S rDNA copy numbers of amylolytic and lipolytic bacteria, such as Succinivibrio dextrinosolvens, Ruminobacter amylophilus and Anaerovibrio lipolytica, attached to corn kernels were increased for processed corn silage (P < 0.05), in particular at 2 h after the start of incubation. In addition, corn stemattached cellulolytic and hemicellulolytic bacteria, such as Fibrobacter succinogenes, ruminococci and Eubacterium ruminantium, increased in 16S rDNA copy numbers for processed corn silage (P < 0.05). This was observed for the initial incubation period from 10 min to 2 h. These results demonstrate more rapid attachment and heavier colonization of rumen bacteria to the processed compared with the unprocessed silage, which facilitates ruminal digestion and fermentation.Key words: Corn silage, mechanical processing, rumen fermentation, bacteria, attachment Kozakai, K., Nakamura, T., Kobayashi, Y., Tanigawa, T., Osaka, I., Kawamoto, S. et Hara, S. 2007. Incidence du conditionnement mécanique sur la fermentation in vitro de l'ensilage de maïs dans le rumen ainsi que sur sa colonisation par les bactéries et la dégradation de la matière sèche in situ. Can. J. Anim. Sci. 87: 259-267. Les auteurs ont étudié la fermentation de l'ensilage de maïs conditionné mécaniquement et sa colonisation par les bactéries du rumen dans le cadre d'une série d'expéri-ences in situ et in vitro en recourant à des vaches canulées au rumen. Les données issues des cultures continues simulant le rumen (Rusitec) montrent que le conditionnement de l'ensilage augmente la concentration totale d'acides gras volatils (P < 0,001) tout en réduisant le pH (P < 0,001), sans modification de la concentration d'azote ammoniacal (P > 0,05). Le conditionnement mécanique accroît le taux de disparition in situ de la matière sèche et la quantité totale de matière sèche dégradée, respectivement pour les rafles et les grains de maïs (P < 0,05). In situ, il améliore aussi la fixation initiale des bactéries du rumen responsables de la digestion du maïs, telle que suivie par PCR en temps réel. On note une hausse du nombre de copies de l'ADNr 16S des bactéries amylolytiques et lipolytiques comme Succinivibrio dextrinos...

Characterization of dairy cow rumen bacterial and archaeal communities associated with grass silage and maize silage based diets

“…The higher amount of starch present in MS has been associated with increased relative abundances of members of the families Ruminococcaceae and Succinivibrionaceae [40,41], which is consistent with the positive association of UCG-002, Succinivibrio and UCG-014 with the GS0 fed cows in the present study. Low CH 4 producing cows have been positively associated with lactate and succinate producing bacteria [42].…”

Assessing rumen microbial composition and fibre attachment in dairy cows

“…The higher amount of starch present in MS has been associated with increased relative abundances of members of the families Ruminococcaceae and Succinivibrionaceae (Kozakai et al, 2007;Deusch et al, 2017), which is consistent with the positive association of UCG-002, Succinivibrio and UCG-014 with the GS0 fed cows in the present study. Low CH4 producing cows have been positively associated with lactate and succinate producing bacteria (Danielsson et al, 2017).…”

Effect of roll clearance of mechanical processing of corn silage harvested at the black‐line stage of maturity on carbohydrate and protein utilization in dairy cows

“…Andrae et al (2001) reported that MP with a roll clearance of 1 mm increased total tract starch digestibility by 5%, which was similar to that observed in our trial. Kozakai et al (2007) indicated that MP of corn kernels resulted in quicker bacterial attachment after feeding, possibly due to increased damage on the surface area of the plant material. Intact corn kernels present in the CS tended to be lower as the roll clearance decreased from 5 mm to 1 mm .…”