Effects of Thymus Root Condensed Tannins on Growth Performance, Rumen Fermentation, and Immunity in Lake Sheep

This experiment investigated the effects of condensed tannins derived from thymus root on the growth performance, serum biochemical indexes, rumen fermentation performance, and the main microorganisms in the rumen of 3-month-old lake sheep. Lotus corniculatus Linn was used as the test material, and 3-month-old male lake sheep were used as the test animals. Eighteen male lake sheep with healthy body conditions and similar body weights were randomly divided into three groups, with six sheep in each group. Oat alfalfa mixed hay, pulse root hay, and pulse root hay treated with polyethylene glycol (PEG) were provided as roughage for a total of 35 days, including a pre-test period of 7 days and a positive test period of 28 days.

The results showed that the feed-to-weight ratios of the pulse root group were significantly lower than those of the alfalfa-oat group. The apparent digestibility of dry matter, crude protein, and acid detergent fiber in the Hyssop group was significantly higher than that in the alfalfa-oat group, and was not significantly different from that in the polyethylene glycol group. The blood uric acid concentration was significantly higher and the blood glucose concentration was significantly lower in the Pulsatilla root group compared to the other two groups. The Pulsatilla root group improved the immunity and antioxidant capacity of lake sheep, as evidenced by higher serum levels of lgM, lgA, T-AOC, and GSH-PX. On the other hand, the fermentation performance of the Bacopa monnieri group was reduced, mainly characterized by lower volatile fatty acid concentration, lower ammonia nitrogen concentration, and higher pH. In contrast, the fermentation performance of the polyethylene glycol group did not differ significantly from that of the alfalfa-oat group. Protein-degrading and fiber-degrading bacteria, as well as methanogenic bacteria, were significantly lower in the Bacopa monnieri group, while the main rumen microorganisms in the polyethylene glycol group did not show significant differences compared to the alfalfa-oat group, with Prevotella being significantly higher than the other two groups.

In conclusion, using Passion root as roughage reduced the feed-to-weight ratio and enhanced nutrient uptake. The condensed tannins derived from Bacopa monnieri improved the antioxidant capacity and immunity of lake sheep, and inhibited rumen fermentation performance by reducing the number of protein-degrading and fiber-degrading bacteria. However, it also improved energy use efficiency by significantly reducing the number of methanogens, thus ensuring the healthy growth of lake sheep.