Influence of lasalocid, cationomycin and feeding frequency on the postprandial kinetics of some plasma parameters in the rumen vein, portal vein and mesenteric artery of sheep.
Two adult sheep, A and B, received successively during three experimental periods a forage-based pelleted feed, then the same diet supplemented with 33 mg/kg of lasalocid (L) or cationomycin (C). The feed was given in either eight (sheep A) or two (sheep B) daily meals. After four weeks of adaptation, 11 blood samples were taken through catheters in the rumen vein (RVA) and the mesenteric artery (MAA) in sheep A and in the rumen vein (RVB) and portal vein (PVB) in sheep B over a 5-hour period after the morning meal. Because of a blockage in the catheter it was not possible to measure the effect of C in MAA. Food intake had no immediate effect on the plasma levels measured: the distribution of eight daily meals stabilized plasma levels and made it easier to determine the effect of the ionophores. This effect varied according to the sampling site, the animal and the antibiotic, sometimes contradictorily. All the plasma parameters monitored in RVA were significantly modified by either one of the ionophores. A decrease in plasma albumin concentration (P < 0.05) was observed with L in MAA and with C in RVA and MAA. Aceto-acetate concentration decreased (P < 0.05) with L in MAA but increased with L and C in RVB. A decrease in glycaemia and uraemia (P < 0.05) was observed with L in MAA, RVA and RVB and with C in RVA. Total amino acid concentration decreased (P < 0.05) with C in RVA or increased (P < 0.05) with L in PVB and RVB. These variations in results may be due to different mechanisms of action of L and C on digestion, particularly in the rumen. While the changes undergone by the ketone bodies in the blood suggested a decrease in hepatic ketogenesis with L, there was no evidence that the ionophores had a direct postprandial effect.
Gomez
L
L
I.N.R.A. Centre de Recherches de Clermont-Ferrand/Theix, Unité de la Digestion Microbienne, St Genes Champanelle, France.
Jouany
J P
JP
Lefaivre
J
J
D000090:Acetoacetates / Q000097:blood; D000821:Animal Feed; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D001806:Blood Urea Nitrogen; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005663:Furans / Q000494:pharmacology*; D006885:Hydroxybutyrates / Q000097:blood; D007700:Kinetics; D007832:Lasalocid / Q000494:pharmacology*; D008638:Mesenteric Arteries; D011169:Portal Vein; D012417:Rumen / Q000098:blood supply*; D012709:Serum Albumin / Q000187:drug effects / Q000378:metabolism; D012756:Sheep / Q000502:physiology*; D013997:Time Factors; D014508:Urea / Q000097:blood; D014680:Veins
D000090:Acetoacetates; D000900:Anti-Bacterial Agents; D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D005663:Furans; D006885:Hydroxybutyrates; D012709:Serum Albumin; C016635:acetoacetic acid; C022174:cationomycin; D014508:Urea; D007832:Lasalocid