Performance and Carcass Quality of Steers Supplemented with Zinc Oxide or Zinc Methionine

Abstract

Forty-five Angus steers (avg initial wt 330 kg) were individually fed for 112 d to assess the value of supplemental Zn and source on performance and carcass quality. Steers had ad libitum access to a control diet (81 ppm Zn) of 33% whole corn, 33% ground milo, 15% cottonseed hulls and 13% cottonseed meal, or this control diet with 360 mg Zn/d added from either zinc methionine or zinc oxide. Steers were slaughtered on d 114, and carcass composition was determined by specific gravity. Average daily gain and feed efficiency were not affected by dietary treatments. Steers fed zinc methionine had a higher (P less than .05) USDA quality grade than those fed the control and zinc oxide diets. Marbling score was higher (P less than .05) for steers fed zinc methionine than for those fed control and zinc oxide treatments (4.4 vs 4.0 and 4.0, respectively, where 3 = slight, 4 = small, 5 = modest). Steers fed zinc methionine tended to have more (P less than .10) external fat (13 mm) than steers fed the control diet (10 mm); steers supplemented with zinc oxide had intermediate amounts of external fat (11 mm). Steers fed zinc methionine had 10.5 and 12.8% more (P less than .05) kidney, pelvic and heart (KPH) fat than steers fed control or zinc oxide diets, respectively. The effects of zinc methionine on carcass quality grade and marbling score may be due to Zn and (or) methionine. Regardless of the mechanism, the difference represents a potential economic benefit to producers.

Changes in chicken intestinal zinc exporter mRNA expression and small intestinal functionality following intra-amniotic zinc-methionine administration

“…Experiments have shown that feed containing ZnMet results in a positive woolgrowth response in sheep and an increase in lambs' daily weight gain ( P b.05) [41]. In addition, steers fed ZnMet had better carcass quality and greater marbling scores than controls [42]. Further experiments revealed that the number of red blood cells ingested per phagocytic cell is increased ( P b.05) following 80 ppm ZnMet supplementation in weanling pig feed [43].…”

Biology of Zinc and Biological Value of Dietary Organic Zinc Complexes and Chelates

“…Growth and concentrations of Zn in tibiotarsus and liver were not affected by the Zn source (Pimentel et al 1991). Carcass quality of steers was improved with a Zn methionine supplement to the diet instead of ZnO (Greene et al 1988). The better carcass quality was not associated with improved performance.…”

Effects of zilpaterol hydrochloride and zinc methionine on growth performance and carcass characteristics of beef bulls

“…Carcass characteristics were not affected (P 0.05) by ZM, but interactions (Table 3) indicated that bulls fed ZH plus ZM had the lowest (P B0.01) backfat thickness and IMF. Previous studies evaluated ZM effects on IMF thickness and backfat thickness in steers, but not the interaction ZH )ZM (Greene et al 1988;Malcom-Callis et al 2000;Spears and Kegley 2002). Zinc has a lipogenic effect (Tang and Shay 2001;Park et al 2003;Vardatsikos et al 2013) caused by inhibition of lipolytic substances (May and Contoreggi 1982;Oh and Choi 2004) and by changing expression of transcript factors and genes responsible for triglycerides and lipoproteins synthesis (Oh and Choi 2004).…”

“…Zinc has been related to several mechanisms, such as being a lipogenic compound (Malcom-Callis et al 2000;Oh and Choi 2004), stimulating lipogenesis and inhibiting lipolysis (Coulston and Dandona 1980;May and Contoreggi 1982) through insulin signaling (May and Contoreggi 1982;Saltiel and Kahn 2001;Eom et al 2001;Park et al 2003). Adding Zn to diets favors the deposition of fat and the degree of marbling in meat of feedlot cattle (Greene et al 1988;Spears and Kegley 2002). Adding organic Zn produces better results than inorganic sources (MalcomCallis et al 2000;Spears and Kegley 2002;Nunnery et al 2007).…”