Influence of yucca extract on ruminal metabolism in cows3

Abstract

Two trials were conducted to determine the influence of yucca extract on ruminal digestion, fermentation, and ammonia patterns using ruminally and duodenally cannulated dairy cows. In Trial 1, urea at 0 or 1% of the diet and yucca extract at 0 or 4 g/d formed four dietary treatments in a 2 x 2 factorial arrangement. The experimental design was a 4 x 4 Latin square with 15-d periods. Duodenal digesta were sampled every 6 h during the last 4 d of each period to determine OM and ADF digestibilities and bacterial protein synthesis in the rumen using Cr2O3 and 15N markers. Ruminal digestibilities were (percentage): OM 46.3 vs 43.0%, and ADF 35.9 vs 41.4%, with or without Deodorase. Microbial protein entering the duodenum averaged 2.7 vs 3.1 kg/d for the respective treatments. Ruminal measurements were not affected by treatment (P > .10). In Trial 2, five cows were used in a 5 x 5 Latin square with 7-d periods. Treatments were 0, 2, 4, 6, and 8 g/d of yucca extract administered via ruminal cannulas. Ruminal fluid was sampled 0, 1, 2, 4, 7, 11, 16, and 22 h after feeding during the last 2 d of each period. Average ruminal NH3 N ranged from 31.4 to 35.4 mg/dL, pH 5.99 to 6.18, and total VFA from 120 to 129 mM, and all did not differ among treatments (P > .10). Yucca extract administered at 4 g/d did not significantly affect ruminal digestibilities of OM and ADF, and up to 8 g/d did not affect ruminal NH3, pH, or VFA.

The effect and mode of action of saponins on the microbial populations and fermentation in the rumen and ruminant production

“…Conversely, Hussain & Cheeke (41) found a numerically lower propionate concentration in vivo with 75 ppm of Yucca saponins. However, Valdez et al (29) and Wu et al (40) did not observe a significant change in propionate concentration in vivo up to 77 and 125 ppm, respectively, of Yucca saponins. The responses of saponins on rumen VFA production are often diet dependent.…”

“…There are reports that milk yields and the composition of milk from moderate-or high-yielding cows (20 -30 kg/d) are not improved by inclusion of Yucca or Quillaja extract in diets containing 10 to 20 % crude protein (25,29,30,36,37,40,42) . Even supplementation of diets containing less than 10 % protein with Yucca saponins (0·1 g/kg) did not affect milk production (119) .…”

“…Sapindus saponaria (27) and Yucca extract (42) included in concentrate diets did not significantly reduce rumen ammonia concentrations, although it should be noted that the Yucca extract did not affect rumen protozoal numbers either. In studies with dairy cows, inclusion of sarsaponins up to 77 parts per million (ppm) of diet (29,33) , 9 g/d (36) , 8 g/d (40) and 10 g of Yucca whole plant (equivalent to 0·6 g saponins/kg DM) or 10 g Quillaja whole plant (equivalent to 0·3 g saponins/kg DM) (25) did not influence ammonia concentrations in the rumen, probably due to low concentrations of saponins inclusion in the diets. Valdez et al (29) and Hess et al (27) have reported that by decreasing protozoal numbers slightly, saponins increased bacterial numbers, which may explain why saponin treatments are not always associated with reduced rumen ammonia concentrations.…”

“…Additionally, the glycofractions of saponins are known to bind ammonia when concentrations of ammonia are low and when a high dose of saponins is added (44) . This might improve N efficiency by maintaining adequate rumen ammonia (trapping of rumen ammonia when ammonia concentrations are high after feeding and then slowly releasing it with the degradation of the glycofraction and desaturation of ammonia binding) for use during microbial protein synthesis when ammonia concentrations decrease (36,40) . However, it has been shown that this ammonia binding appears to be negligible at ammonia concentrations typical of the rumen (44) .…”

Use of ‘natural’ products as alternatives to antibiotic feed additives in ruminant production

“…The strong bioactivity of saponins, associated with the possibility for rumen microbes to deglycosylate them, explain why their effect on animal performances is rather inconsistent (Mader and Brumm, 1987;Wu et al, 1994;Calsamiglia et al, 2005), and generally low when animals have been treated over a long period (Table 2).…”