著者・編者Kodithuwakku Arachchilage, Heshan Taraka Kodithuwakku
並列タイトル等繊維飼料の早期経口投与が哺乳子牛の胃腸内環境に及ぼす影響
一般注記Calf health in the pre-weaning period is an important aspect for the future productionof cattle. To ensure the healthy growth of neonatal animals, anatomical and functionaldevelopment of the gastrointestinal tract is a key not only for nutrient acquisition but alsofor preventing infectious diseases. Establishment of the gastrointestinal microbiota is vitalfor the development of gastrointestinal functions, such as feed digestion, provisioning ofnutrients to the host, and developing the immune system. The supplementation of roughageto calves during the pre-weaning period shows beneficial effects, such as improvement infeed intake, growth performance, rumination, and rumen environment. In my master’s study,it was confirmed that oral administration of a fibrous diet from 3 days of age improves thebody weight and fecal microbiota (i.e., higher abundance of Lactobacillus spp. andPrevotella spp.; lower abundance of Clostridium perfringens) of calves within the first 3weeks of life. This study aims to further assess the effects of oral fiber administration onhindgut microbiota and investigate the impacts on rumen microbiota.1. Investigation of the beneficial effects of fibrous diet on hindgut microbiota.Timothy hay and psyllium, which were the ingredients of fibrous diet for oraladministration to calves, were separately evaluated by in vitro batch culture experimentusing the calf feces as inocula. Lactobacillus spp. were enhanced solely by timothy hay,whereas Prevotella spp. were enhanced solely by psyllium. Furthermore, these effects weremore obvious by adding the water-soluble fraction compared to the insoluble fraction. Thespecies composition of the Lactobacillus spp. enhanced by fibrous diets was characterizedby the near full-length sequencing of the 16S rRNA gene. A higher proportion (> 60%) ofthe detected Lactobacillus species were represented by uncultured (g) Lactobacillus, andthey were phylogenetically closely related to L. johnsonii, L. gasseri, and L. taiwanensis.2. Alterations in rumen microbiota via oral fiber administration during early life indairy cowsThis study evaluated the effects of oral fiber administration during the pre-weaningperiod on the development of rumen microbiota from pre-weaning to the first lactationperiod. Twenty female calves were assigned to control and treatment groups (n = 10 each).Animals in both groups were reared using a standard feeding program throughout theexperiment, except for oral fiber administration (50?100 g/day/animal) from 3 days of ageuntil weaning for the treatment group. Rumen content was collected during the pre-weaningperiod, growing period, and after parturition. Amplicon sequencing of the 16S rRNA generevealed that oral fiber administration facilitated the early establishment of mature rumenmicrobiota, including a relatively higher abundance of Prevotella, Shuttleworthia,Mitsuokella, and Selenomonas. The difference in the rumen microbial composition betweenthe dietary groups was observed even 21 days after parturition, with a significantly higheraverage milk yield in the first 30 days of lactation. Therefore, oral fiber administration tocalves during the pre-weaning period altered rumen microbiota, and its effect might be longlastinguntil the first parturition.In conclusion, this study demonstrated that the fibrous diet enhances beneficial gutbacteria and the establishment of rumen microbiota in pre-weaned calves. Thesemodulations of gastrointestinal microbiota could lead to improved host productivity, suchas growth and milk yield.
(主査) 教授 小池 聡, 教授 上田 宏一郎, 特任教授 小林 泰男, 助教 鈴木 裕
農学院（農学専攻）
コレクション（個別）国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
受理日（W3CDTF）2023-10-11T15:41:06+09:00
連携機関・データベース国立国会図書館 : 国立国会図書館デジタルコレクション