Short communication: Effects of different selenium supplements on rumen fermentation and apparent nutrient and selenium digestibility of mid-lactation dairy cows

Abstract

The aim of this study was to evaluate the dosedependent effects of a hydroxy-analog of selenomethionine (HMSeBA) on rumen fermentation, apparent nutrient digestibility, and total selenium absorption in mid-lactation dairy cows, and to compare the effects with those of sodium selenite (SS). Fifty mid-lactation dairy cows with similar milk yields, days in milk, and parity were randomly assigned to 1 of 5 treatments according to a randomized complete block design. The cows were fed a basal diet containing 0.06 mg/kg dry matter (DM) of Se (control) or the same basal diet supplemented with SS, yielding 0.3 mg of Se/kg of DM (SS-0.3), or HMSeBA, yielding 0.1, 0.3, or 0.5 mg of Se/ kg of DM (SO-0.1, SO-0.3, and SO-0.5, respectively), during the experimental period. The final content of Se in control, SS-0.3, SO-0.1, SO-0.3, and SO-0.5 was 0.06, 0.34, 0.15, 0.33, and 0.52 mg of Se/kg of DM.The experiment lasted for 10 wk, with a pretrial period of 2 wk. Supplementation with HMSeBA altered rumen fermentation by linearly increasing total volatile fatty acids and the molar proportions of propionate and butyrate but decreasing rumen pH, ammonia content, and the ratio of acetate to propionate. Compared with SS, HMSeBA enhanced the molar proportion of propionate in the rumen and the apparent digestibility of crude protein, neutral detergent fiber, acid detergent fiber, and selenium. We demonstrated that HMSeBA promoted rumen fermentation, apparent nutrient digestibility, and selenium absorption, implying that HMSeBA has a greater apparent absorption than SS.

Food for thought: nano-selenium in poultry nutrition and health

“…It was demonstrated that OH-SeMet affected rumen bacteria differently than sodium selenite, resulting in promotion of rumen fermentation (e.g. increasing total volatile fatty acids and the molar proportions of propionate and butyrate but decreasing rumen pH, ammonia content, and the ratio of acetate to propionate), apparent nutrient digestibility and selenium absorption (Wei et al ., 2019).…”

Selenium Biofortified Alfalfa Hay Supplemented to Dairy Heifers During the Peripartum Affects the Antioxidant Function of Albumin but Has Little Impact on Metabolic and Immune Function

“…Thus, it is possible that the larger urea in the blood was the consequence of a combined improved capacity of the liver to synthesize urea and larger re-absorption of urea by the kidney. Data produced in vitro [46] and in vivo [47] demonstrated a positive effect of organic Se supplementation on rumen fermentation in dairy cows. Thus, it is possible that the larger concentration of plasma urea observed in our study was also due to greater production of microbial proteins.…”

Copper sulfate and sodium selenite lipid-microencapsulation modifies ruminal microbial fermentation in a dual-flow continuous-culture system

“…Shifts in ruminal fermentation after supplementing inorganic Se may be indicative of either a requirement of Se by ruminal microorganisms or an alteration of fermentation by the chemical reduction of Se compounds (selenate to selenite to elemental Se). Nevertheless, changes in VFA and ruminal fermentation have also been reported in dairy cows (Wei et al, 2019) fed 0.3 and 0.5 mg/kg of organic Se (hydroxy-analog of Se-methionine), which may be a response of ruminal microorganisms to the AA analog rather than an effect of Se.…”

“…Inorganic forms of Se may undergo chemical reduction in the rumen by the action of ruminal microorganisms (Eun et al, 2013), and hence be partially converted to forms of Se with low molecular weight that have not been chemically identified, but are less available to the animal (Weiss, 2005;Suttle, 2010). Moreover, although positive effects of organic forms of Se on ruminal fermentation have been recently reported (Wei et al, 2019), the effects of inorganic Se on ruminal fermentation are not clear (Serra et al, 1994;Kim et al, 1997;Eun et al, 2013). Therefore, there is a critical need to better understand factors that affect ruminal metabolism of Cu and Se and their effects on ruminal fermentation.…”