부산대학교 도서관

The objective was to determine if rumen microbial characteristics differed in goats selectively bred for greater consumption of Juniperus pinchotii. Ten Boer × Spanish-composite bucks (age = 2 yr; initial BW = 67.2 ± 4.3 kg) previously selected for high (HIGH; n = 5) or low (LOW; n = 5) juniper-consumption, were subjected to three periods: Period 1, d 0, grazing native range predominated with Juniperus spp.; Period 2, d 1 to 26, fed ad libitum hay; and Period 3, d 27 to 63, fed 3% of BW of hay and ad libitum J. pinchotii offered fresh daily. During each Period (d 0, 24, and 61), ruminal fluid was evaluated for microbial species composition and diversity. Within Period 1, Shannon’s bacterial index of LOW tended to be greater (P = 0.06) than HIGH; no differences (P > 0.44) were observed within Periods 2 or 3. For archea, Shannon’s diversity index was greater (P = 0.03) in Period 2 vs. 1 and greater (P = 0.04) in Period 3 vs. 1. PERMANOVA analysis using square root transformed sequence counts of bacterial phyla with treatment nested within Period, indicated that Period and treatment significantly affected microbial community composition (P < 0.01); within Period, treatments had different (P < 0.02) bacterial communities. Distance-based redundancy analysis indicated environmental variables that best explained variation in bacterial communities were expected breeding value for juniper consumption and ruminal pH and acetate (P < 0.003), with 8.5, 20.5, and 7.2%, respectively, of the variation in bacterial communities. Ruminal pH best explained the variation in archaeal communities. Results suggested that clustering is potentially driven by expected breeding values.