Effect of Steroidal Sapogenins on Ruminal Fermentation and on Production of Lactating Dairy Cows

Abstract

Supplementation of dairy rations with steroidal sapogenins was evaluated in an in vitro, an in situ, and a production trial. Sixteen in vitro semicontinuous rumen cultures were supplied a 55:45 concentrate to roughage substrate with Sarsaponin concentrations of 0, 33, 55, and 77 ppm of air-dry feed for 22 d. Supplementation decreased protozoa numbers and increased bacterial numbers and acid detergent fiber digestion. Digestion of feed nitrogen tended to be lowest at the highest concentration of Sarsaponin, whereas microbial nitrogen output was similar for all concentrations. In rumen-cannulated animals fed a typical dairy ration, in situ rate of disappearance of organic matter, acid detergent fiber, and nitrogen of a complete ration substrate tended to be lower with 77 ppm added Sarsaponin. In a production trial, 16 primiparous dairy cows 6 to 10 wk postpartum were fed rations containing either 0 or 77 ppm Sarsaponin. Sarsaponin did not alter dry matter intake, digestibility, body weight change, or milk production and composition. Supplementation had no significant effect on ruminal fermentation in vivo as reflected by concentrations of ruminal ammonia nitrogen, blood urea, or molar ratios and concentrations of ruminal volatile fatty acids.

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.…”

“…One of the earliest observations was made by Valdez et al (29) who showed that a commercial sarsaponin (steroidal spirostanol saponin) extracted from the Yucca schidigera plant decreased the protozoal population with a small increase in bacterial numbers in continuous culture systems. In many subsequent studies, the extracts of Y. schidigera have been shown to suppress the growth of rumen protozoa in vitro (44) without affecting DM disappearance and other rumen microbial populations (45) .…”

“…Goetsch & Owens (33) reported a significant increase in the digestibility of organic matter in cattle fed 44 ppm of Yucca saponins. Valdez et al (29) recorded an increased digestibility of organic matter, together with a tendency toward an increased digestibility of acid-detergent fibre with increasing application levels of Yucca extract (up to 77 ppm). Pen et al (24) reported an increase in neutral-detergent fibre digestibility by sheep supplemented with Quillaja saponins.…”

“…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.…”