Omnigen-AF® Supplementation May Attenuate Liver Damage during a High Concentrate Diet in Finishing Steers

To determine the effect of OmniGen-AF^® (a patented nutritional specialty product from Phibro Animal Health Corporation) supplementation on markers of metabolism and liver function in steers during backgrounding, transition and finishing phases, nine purebred Angus half-sibling steers were divided into one of two treatment groups; Control (CNTL n=4) and OmniGen-AF^® (OG; n=5). Cattle were offered 0 (CNTL) or 56 g/hd/d of OG through a 28-d backgrounding period (limit-fed a predominantly forage-based diet; P), a 14-d transition period (T), and finished on a high-concentrate diet for 56 d (104 days total; F). Serum was collected on days 0, 14, 21, 28, 35, 43, 56, 70, 84, 98 and 104 for haptoglobin, metabolites and markers of liver function as measured by paraoxonase, albumin, AST and GGT. Data were analyzed using repeated-measures-in-time analysis in PROC MIXED. Fixed effects of the statistical model were treatment (CNTL and OG), dietary phase, day (nested within phase), and their interactions. The values and variation of serum AST and GGT increased at the end of the finishing phase, resulting in a bimodal distribution prior to and at the end of finishing; thus, we examined AST and GGT concentrations with a separate analysis on days 84, 98 and 104. A diet phase effect was present for metabolites and markers of liver function (P<0.05); the interaction of diet phase and OG supplementation had no effect on metabolites, AST, paraoxonase or albumin. GGT tended to increase in OG steers while in CNTL steers GGT decreased (P=0.08) during the backgrounding phase. OG supplementation during the entire experiment (104 days) increased serum haptoglobin concentrations (P=0.0002), and decreased serum NEFA concentrations (P=0.002). OG supplementation also assuaged the decline in paraoxonase concentrations (P=0.02) and tended to reduce the increase of a marker of liver cell necrosis (AST; P=0.07) at the end of the finishing period (compared to control cattle on days 84, 98 and 104 of supplementation). Based on these data, we conclude that OG supplementation may attenuate liver damage during a high concentrate diet in finishing steers.