The effect of protein degradation products in grass silages on feed intake and intake behaviour in sheep

Abstract

The effects of NH, and amines on grass-silage intake, intake behaviour and rumen characteristics were studied in sheep. From a single sward, two direct-cut grass silages were prepared, either untreated (WAS) or with 4 5 1 formic acidltonne (FAS). Four experimental diets: WAS, FAS, FAS with addition of 2.9 g NH,bg DM (FAS+N) and FAS with 2-8 g aminesbg DM @AS+ A), were offered ad lib. once daily to four rumen-cannulated wethers in a 4 x 4 Latin square design. Daily DM intake (DMI) tended to be influenced by dietary treatment (P = 0.09). Compared with FAS, DMI was lower for WAS. Addition of NH, did not alter DMI, whereas amine addition slightly lowered daily DMI.Reduced DMI resulted from lower intake rates during both the principal meal and the subsequent small meals. Lower initial intake rate during the principal meal suggested reduced palatability of WAS and FAS+A. Amines and NH3, however, did not influence chewing efficiency. No treatment effects were observed on total rumen pool size, DM and neutral-detergent fibre content. Furthermore, NH, and amines did not alter rumen pH, NH, and volatile fatty acid concentrations to the extent that they could act on chemostatic intake regulation. Amine addition, however, lowered osmolality of the rumen liquid. No treatment effects on rumen motility were observed. In conclusion, daily DMI was not reduced by the addition of NH,, suggesting that NH,per se is not the causal factor in the negative correlations between silage NH, content and intake observed by other authors. Amines, however, tended to reduce DMI only by their effect at the oro-pharyngeal level of intake control.Silage: Feed intake: Ammonia: Amines: SheepThe generally lower voluntary intake of grass silages compared with hay prepared from the same fresh forage or with the fresh forage itself is mainly attributed to fermentation endproducts present in the silage. This reduction in intake varies widely (ranging from 0 to 64 %) and is related to the quantities of the fermentation products in the silage, which vary with the method of preservation (Demarquilly, 1973 ; Donaldson & Edwards, 1976; Thiago et al. 1992~). These fermentation products (organic acids, NH,, amines) may regulate intake by their oro-pharyngeal properties (taste, smell) or metabolically (metabolites in rumen and/or blood; Gill et al. 1987). Rumen fill appears to be of minor importance in controlling silage intake, because rumen DM content remains lower when the animals are fed on silages compared with hays prepared from the same original herbage (Thiago & Gill, 1986;Chiofalo et al. 1992). Relationships between silage constituents and intake suggest that NH, is one of the factors responsible for reduction in intake of poor-quality silages

Profiling of metabolome and bacterial community dynamics in ensiled Medicago sativa inoculated without or with Lactobacillus plantarum or Lactobacillus buchneri

“…In addition, L. buchneri inoculation also caused remarkable accumulation of cadaverine in silages, which agrees with the results of previous studies 20 . High accumulation of biogenic amines produced by some strains of L. buchneri may lower the palatability or eating rate of the silage 21 . However, silages inoculated with L. plantarum showed a significant down-accumulation in cadaverine.…”

Effect of Soybean Meal and Soluble Starch on Biogenic Amine Production and Microbial Diversity Using In vitro Rumen Fermentation

“…Thus, greater amounts of amines are available for absorption in ruminants than other species. Nevertheless, increased contents of dietary amines tend to reduce dry matter intake ( Van Os et al, 1995 ), nitrogen degradability in the rumen of steers, particularly by the biogenic amine (BA) putrescine ( Dawson and Mayne, 1997 ), have negative effects on visceral organs and meat quality ( Fusi et al, 2004 ) of ruminants, hence it has been considered disadvantageous. Functional studies regarding the relationship between BA histamine concentration and hyperacidity during metabolic studies has been reported in non ruminants as well as in ruminants.…”

Effect of γ-Aminobutyric Acid (GABA) Producing Bacteria on <italic>In vitro</italic> Rumen Fermentation, Biogenic Amine Production and Anti-oxidation Using Corn Meal as Substrate

“…Ruminants potentially receive amines from both dietary and ruminal microbial sources and thus have the potential to absorb greater amounts than other species. Increased contents of dietary amines have been considered disadvantageous in ruminant nutrition since these substances tend to reduce dry matter intake (Van Os et al, 1995) and nitrogen degradability in the rumen of steers, particularly by the BA putrescine (Dawson and Mayne, 1997) and have negative effects on visceral organs and meat quality (Fusi et al, 2004). …”