Effects of Diaryliodonium Chemicals on Rumen Fermentation In Vitro and In Vivo

Abstract

In vitro fermentation studies demonstrated that diaryliodonium chemicals were inhibitors of amino acid utilization. Only small differences were found in comparative effectiveness of different analogs and salt forms of chemicals tested. Protection against degradation and(or) uptake was greatest for valine, methionine, isoleucine, leucine and phenylalanine. Although changes were not as large, animals fed 4,4'-dimethyldiphenyliodonium chloride for 112 d had higher ruminal concentrations of amino acids and lower concentrations of ammonia. Decreased production of acetate in conjunction with increased production of propionate and butyrate resulted in improved fermentation efficiencies. Fermentative shifts in vivo were not as large as those observed in vitro and additional investigations are needed to determine whether feeding diaryliodonium chemicals increases the transfer of energy in digested carbohydrates to volatile fatty acids.

Effect of Thymol or Diphenyliodonium Chloride on Performance, Gut Fermentation Characteristics, and Campylobacter Colonization in Growing Swine

“…Thymol and DIC have been investigated as feed additives that can be used to reduce the energetically wasteful process of ruminal protein degradation in cattle without producing adverse effects on animal health (2,5). Varel and Miller (24) recognized the deaminase inhibiting potential of DIC for controlling gaseous emissions from livestock waste, and in vitro studies revealed that inhibition of amino acid metabolism by these chemicals may be a metabolic target for the control of foodbome Campylobacter (1).…”

The Rumen Microbial Ecosystem

“…The dipeptidase activity in rumen fluid is metal ion dependent and is inhibited in vitro by I,lO-phenanthroline (Wallace et aI., 1996). Diaryliodonium compounds inhibited deaminase activity in vitro and in vivo (Chalupa et al, 1983a;Van Nevel and Demeyer, 1990). The great majority of peptidase activity in the rumen involves aminopeptidase ; thus, N-terminally blocked pep tides have a high degree of resistance to ruminal degradation (Wallace, 1992;Wallace et aI., 1993b) and peptides were protected effectively from degradation in vivo by N-terminal acetylation (Witt, 1993).…”

“…However, as for protein, potentially the most promising mechanism of reducing peptide breakdown is to modify the substrate. Dimethyldiphenyliodonium chloride (DDIC) stimulated propionate production and reduced methanogenesis in vitro and in vivo (Chalupa et al, 1983a;Van Nevel and Demeyer, 1992), and nitrogen retention and live weight gain increased in cattle fed a low-protein diet supplemented with DDIC (Chalupa et aI., 1983a,b,c). Amino acid deamination.…”

Effects of thymol and diphenyliodonium chloride against Campylobacter spp. during pure and mixed culture in vitro

“…However, inhibition of amino acid catabolism by Campylobacter cannot be excluded. Both diphenyliodonium chloride and thymol, or an essential oil product containing thymol, have been studied in ruminants for their ability to reduce the energetically wasteful process of ruminal protein degradation (Broderick and Balthrop 1979; Chalupa et al. 1983a,b; Newbold et al.…”

“…Precedence exists for the application of thymol and diphenyliodonium chloride to animals. For instance, diphenyliodonium chloride and an essential oil product containing thymol have been administered to ruminants, as inhibitors of the energetically wasteful process of ruminal protein degradation, with no reported adverse effects in short term studies (Chalupa et al. 1983a,b; Newbold et al.…”