Does humate supplementation affect ciliate population
and fermentation parameters in the sheep rumen?

The objective of the study was to examine the effect of supplementing sheep diets with humic substances (HS) on the number of protozoa and short chain fatty acid and methane concentrations in the rumen. The experiment was carried out in three rumen-fistulated sheep. The control (CON) ration was composed of 59.70% hay and 40.30% concentrate. Two experimental diets consisting of the same components were supplemented with two doses of humic substrates, 10 (HS10) or 20 (HS20) g/day/animal. The population of total protozoa and the genera Entodinium and Isotricha in the rumen was the most abundant before feeding (0 h) and decreased 2 and 4 h after receiving the diets. The populations of total protozoa and the genus Entodinum in the rumen were more abundant 2 h after administration of HS10 and HS20 compared to CON. The counts of these groups of protozoa increased 8 h after feeding HS10 compared to CON and HS20. An interaction trend (sampling time × treatment) was detected in terms of the number of Isotricha spp. in the rumen. The postprandial (2 and 4 h) pH of the rumen was lower than 0 h and 8 h after feeding CON and HS. Short chain fatty acid concentration was higher 2 and 4 h after feeding compared to 0 h and 8 h postprandial. An interaction trend was as assessed based on acetic acid levels; the highest was observed 4 h after feeding HS20 and the lowest 8 h after feeding HS10. Butyrate concentration was lower 8 h after feeding compared to 2 and 4 h postprandial levels for sheep fed the CON and HS10 diets. Branched chain acid production was the lowest 8 h after feeding compared to 0 h and 2 h after HS10 administration. An interaction trend was observed for methane levels; the highest was showed 4 h after feeding HS20 and the lowest 8 h after feeding HS10 diets. HS supplemented to sheep diets increased the abundance of total protozoa and the genera Entodinium and Isotricha in the rumen. It seemed that humates could modify the production of acetate and methane in the rumen, as slight increases in these parameters were observed. This suggests that humic substances can intensify methanogenesis in the rumen.

FUNDING

This work was supported by the statutory funding of The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences.

CONFLICT OF INTEREST

The Authors declare that there is no conflict of interest.

METADATA IN OTHER LANGUAGES:

Chinese

腐植酸对绵羊瘤胃内纤毛虫种群和发酵参数有影响吗？

摘要: 本试验旨在研究在绵羊日粮中添加腐殖质（Humic substances，HS）对瘤胃内原虫数量、短链脂肪酸和甲烷浓度的影响。试验使用3只瘤胃瘘管绵羊。对照组（CON）日粮由59.70%干草和40.30%精料组成。在两种成分相同的日粮中分别添加10（HS10）或20（HS20）g/d动物腐殖质。瘤胃内总原虫、肠菌属和等毛菌属在饲喂前（0 h）数量最多，饲喂2 h和4 h后下降。与CON相比，HS10和HS20处理2 h后瘤胃内原虫和肠内菌属数量更丰富。与CON和HS20相比，HS10的原虫数量在8 h后有所增加。瘤胃内等毛虫数量呈交互作用趋势 (采样时间×处理）。饲喂CON和HS后2 h和4 h瘤胃pH均低于0 h和8 h。短链脂肪酸浓度在饲喂后2 h和4 h显著高于餐后0 h和8 h。根据醋酸水平评估相互作用趋势，在饲喂HS20后4 h最高，在HS10之后8 h最低。饲喂CON 和HS10日粮的绵羊在饲喂8 h后丁酸浓度低于饲喂后2 h和4 h。与HS10给药0 h和2 h相比，给药8 h后支链酸产量最低。甲烷水平有交互作用的趋势，最高出现在饲喂HS20后4 h，最低出现在饲喂HS10饲料后8 h。观察到甲烷水平的相互作用趋势；投喂HS20后4 h最高，投喂HS10后8 h最低。在绵羊日粮中添加HS能提高瘤胃内原虫总数和内毛虫属、等毛虫属的丰度。腐殖质似乎可以改变瘤胃中乙酸和甲烷的产量，因为观察到这些参数略有增加。这表明腐殖质可以强化瘤胃内的甲烷生成。

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