Investigation of ammonium lactate supplementation on fermentation end products and bacterial assimilation of nitrogen in dual-flow continuous culture

Abstract

Supplements investigated throughout the present study are produced by fermenting lactose that is present in whey to lactate, yielding products differing in ammonium relative to lactate concentrations and in physical form (liquid or dry). Trials 1 and 2 investigated Lacto-Whey (LW; Fermented Nutrition Corp., Luxemburg, WI) and GlucoBoost (GB; Fermented Nutrition Corp.), respectively, using dual-flow continuous culture systems (n = 4), each with a 4 × 4 Latin square design. A greater proportion of nonprotein nitrogen was present in GB than in LW. In trial 1, the treatment with LW was isonitrogenously dosed against soybean meal (SBM) as a control (no LW) and factorialized with either a wheat- or corn-based concentrate (55% inclusion rate, dry matter basis). We hypothesized that LW would increase propionate production and that the combination of +LW with wheat would increase bacterial assimilation of NH-N into cellular N. No differences were observed for total volatile fatty acid (VFA) production per day. However, treatment × time interactions revealed that +LW increased lactate concentration at 0, 0.5, and 1 h and tended to increase molar percentage of propionate at 1 and 1.5 h postfeeding, documenting the immediate availability of lactate converted to propionate in the +LW treatments. The main effect of corn increased the proportion of bacterial N derived from NH-N. Trial 2 was designed to investigate GB; isonitrogenous treatments included an SBM control, crystal GB, liquid GB (LGB), and LGB with yeast culture, which were dosed twice daily. We hypothesized that GB would increase propionate production and bacterial assimilation of NH-N; the combination of LGB and yeast culture was expected to have a positive additive effect, yielding the greatest VFA production and bacterial NH-N assimilation. No differences were observed for total VFA production; however, LGB decreased molar percentage of acetate and increased propionate and butyrate molar percentages. There were no differences in non-NH-N flow or microbial N flow. Under the conditions of our studies, lactate in LW and GB was fermented extensively to propionate, and microbial protein synthesis in these treatments was comparable with that in SBM controls.

Postpartum supplementation of fermented ammoniated condensed whey improved feed efficiency and plasma metabolite profile

“…As a nutrient source, FACW product is a high-energy feed based on lactate content, but is also high in CP with 55.5% CP on a DM basis, largely in the form of the nonprotein N associated with ammonium lactate. Regarding its value as a protein source, there has been no evidence that isonitrogenous diets containing either FACW or soybean meal yielded different in vitro growth of mixed ruminal microbes (Wagner et al, 2018). Our results are in agreement with the previous continuous culture trial in which diets containing liquid FACW decreased the molar percentage of acetate and increased those of butyrate, propionate, and ammonia-N production compared with isonitrogenous diets containing soybean meal (Wagner et al, 2018).…”

“…The increase in rumen ammonia-N for cows supplemented with FACW was expected because of the nature of the product which contains high amount of NPN. In another study, lactate concentrations were greater in treatments containing FACW until 0100 h postdosing, but largely disappeared after that (Wagner et al, 2018). The transient nature of lactate in the rumen as it is converted to other microbial products offers an explanation for the absence of a significant effect of FACW on rumen lactate concentration in the current trial, given that the first rumen sample collected was about 0130 h after feeding.…”

“…or pyruvate, which is further metabolized to other VFA (Hino and Kuroda, 1993;Prabhu et al, 2012). The ammoniated lactate product fed in this trial is racemic, composed of equal proportions of D and L forms of lactate (Wagner et al, 2018). The shift in fermentation toward increased molar proportions of propionate and butyrate observed in the current trial may be explained by an increase in lactate-utilizing bacteria fermenting lactate preferentially to propionate, and by stimulation of protozoa, primarily producing butyrate (Newbold et al, 1987;Brossard et al, 2004).…”

“…The relative depression of rumen pH with FACW supplementation at 7 DIM but not at 21 DIM compared with control could be related to the aforementioned adaptation period necessary for lactate absorption by the rumen epithelium (Schwaiger et al, 2013;Qumar et al, 2016). However, this differs from a continuous culture trial in which there was no evidence for an effect of FACW on rumen pH (Wagner et al, 2018). It is worth noting that their continuous culture trial did not account for potential differences in DMI caused by FACW, nor for the effects of the absorptive capacity of organic acids by rumen epithelial cells, which is a key determinant of ruminal pH (Resende Júnior et al, 2006;Penner et al, 2009a,b).…”

“…Regarding its value as a protein source, there has been no evidence that isonitrogenous diets containing either FACW or soybean meal yielded different in vitro growth of mixed ruminal microbes (Wagner et al, 2018). Our results are in agreement with the previous continuous culture trial in which diets containing liquid FACW decreased the molar percentage of acetate and increased those of butyrate, propionate, and ammonia-N production compared with isonitrogenous diets containing soybean meal (Wagner et al, 2018). Megasphaera elsdenii, a major lactate-utilizing bacterium, converts l-lactate to propionate and d-lactate to either l-lactate ,5,7,9,11,14,17,21,28,and 45 DIM.…”