Monensin 사료첨가가 한국재래산양의 제일위내(第一胃內) 미생물상과 그 활성에 미치는 영향 = Effects of Feeding Monensin on the Ecosystem of Rumen Microbes and Their Activities in Korean Native Goat

다국어 초록 (Multilingual Abstract)

The present experiments were conducted to determine the effect of feeding monensin on rumen bacterial flora and protozoal fauna, on bacterial enzyme activities involving amylase and urease, on ruminal pH and volatile fatty acids.
Nine Korean native goats averaging 15.6 ㎏ of body weight were randomly alloted to the diets supplemented with monensin at the level of 0, 30 and 60 ppm. After 3 weeks adaptation period the animals were fed the experimental diets. Ruminal fluids were collected and examined just before feeding and 2, 4, 6 and 10 hrs after feeding on days 0, 7, 14, 28 and 42.
The results obtained in this study are summerized as follows:
1. The total number of ruminal protozoa was markedly decreased with monensin diets from the 7th to 28 th day of the experimental period, although it appeared to be recovered gradually towards the end of experiments.
However, a significant difference ( P< .05 ) among tereatments could be noted in the total number of ruminal protozoa throughout the experimental period.
2. A total of 20 protozoal species were detected throughout the period ; 17 species in Ophryoscolacidae, 3 species in Isotrichidae.
The number of those was decreased by monensin diets, so that the protozal composition of monensin groups was simpler than that of the control.
3. The protozoal fluctuation pattern was changed by the monensin treatment, and the fluctuation of each species consisted of the protozoal composition was varied according to not only species, but also treatments.
The counts of protozoa of Holotricha order were appeared to be increased by monensin treatments while no significant differences were noted in counts of protozoa of Spirotricha order except Eudiplodinium species shown slight increase in number.
4. In the total number of ruminal bacteria, nonsignificant difference ( P > .05 ) was observed among treatments throughout the experimental period.
5. Fourteen different kinds of the rumen bacterial types were classified by means of morphology and Green-stain reaction. In the total number of bacterial types, nonsignificant difference ( P>.05 ) was observed among treatments.
6. The bacterial fluctuation pattern was changed by the monensin treatment, and the fluctuation of each bacterial type consisted of the bacterial composition was varied according to bacterial types and monensin levels. The total numbers of Gram-negative bacteria increased (15.78-16.41 %) with monensin treatments, While, the numbers of Gram-positive bacteria decreased ( 69.65-73.09% ) throughout the experimental period.
7. Amylase activity in ruminal fluids of the monensin diet tend to be increased from the 7th to 28 th or 42nd day of the experimental period : although no significant difference in amylese activity was noted among treatments.
8. Urease activity in ruminal fluids of the 30 ppm diet appeared to be increased from the 7 th to 28th day of the experimental period, while the 60 ppm diet tend to be decreased from the 7th to the end of the experiment. However, no significant difference (P >.05) was observed between the 30 ppm and control group, and 60 ppm group was significantly different from the other two groups (P< .05).
9. In the ruminal pH, nonsignificant differences (P>.05) were found among treatments throughout the experimental period.
10. The total ruminal VFA concentration was found not to be affected by the monensin treatments.
11. The molar portion of acetate in rumen fluids were reduced ( P< .05 ) by monensin diets, propionate, however, increased ( P<.05 ) from the 7th to the end of the experiment. The butyrate was significantly decreased at the 60 ppm level ( P< .05 ). Nonsignificant difference ( P>.05)was observed in isovalerate and valerate.