Abstract:

【Objective】 The main objectives of the experiment were to determine the effects of different oils on the bacterial recycling due to predation by rumen protozoa in vitro. 【Method】 Three Xuhuai White Goats fitted with cannulas were used to provide rumen liquid. An one-factor experiment was carried out, and the groups were divided into control group, rapeseed oil (A), soybean oil (B), corn oil (C), and peanut oil (D), respectively. The fluorescence-labeled technique was introduced to investigate the protozoal grazing rate at 10 h after in vitro culture. 【Result】 The results showed that, protozoal densities was the highest in the control group, significantly higher than that of A, B, and C (P＜0.05). Bacteria density was the highest in B (4.906×109cells•mL-1), and higher than that of control group significantly (P＜0.05). No significant diference was detected in protozoal protein (P＞0.05), while significant diference was found in bacterial protein, with the highest data falling in group B, and the bacterial protein of B, C, and D were higher than that of control group (P＜0.05). The grazing rates of protozoa were: 267.6, 196.2, 244.4, 274.4, and 285.4 cells/(cell•h), for control group, A, B, C, and D, respectively. There were significant differences in protozoal grazing rate among groups(P＜0.05). When converted to the predation rates of bacterial N, there were 1.445, 1.059, 0.320, 1.482, and 1.541 pg N•(cell•h)-1, respectively. 【Conclusion】 The estimation of the recycling quantity of bacterial protein by protozoa per goats per day, respectively, were 121.64, 56.64, 78.39, 87.04, and 95.06 mg Pr•(d•head)-1, with B showing a much lower data, just accounting for 64.45% of the control group. And B held the highest microbial protein, thus, B could regulate microbial protein recycling in some degree.

Key words: oil, rumen protozoa, fluorescence-labeled technique, bacterial protein, recycling