Zinc repletion with organic or inorganic forms of zinc and protein turnover in marginally zinc-deficient calves.

Abstract

We conducted two experiments using marginally Zn-deficient (-Zn) calves to determine which supplemental chemical form of Zn would most rapidly reverse certain Zn deficiency signs and to determine whether a change in protein turnover had occurred in Zn deficiency. In Exp. 1, 40 crossbred beef heifers were allocated by BW to four groups. The control group received 23 mg Zn/kg diet DM from ZnSO4 supplemented to the -Zn diet (17 mg Zn/kg diet DM). The three other groups received the -Zn diet. After 21 d, based on a decreased (P < .05) feed efficiency, they were deemed -Zn. Cell-mediated immune (CMI) response to phytohemagglutinin (PHA) was reduced (P < .05) but plasma and liver Zn were unaffected in the -Zn calves. Zinc was repleted by feeding iso-Zn amounts (23 mg Zn/kg diet DM) from Zn lysine, Zn methionine, or ZnSO4. At 8 h after injection of PHA, control CMI response values were similar to Zn Methionine, and Zn lysine was lower (P < .05). In Exp. 2, 10 Holstein steers were allocated by BW to two groups. One group received the -Zn diet, and the other received the +Zn diet. Urine collections were obtained from both groups of calves when the -Zn calves showed a decrease (P < .05) in feed efficiency relative to the controls and when they were repleted with 23 mg Zn/kg diet DM from ZnSO4 and their feed efficiency had returned to that of the controls. Urinary 3-methylhistidine indicated that -Zn calves had less (P < .05) daily protein degradation than the controls. Refeeding Zn to the -Zn group did not change BW or daily protein degradation. Results indicated that a marginal Zn deficiency decreased fractional accretion rate, increased (P < .05) urine excretion, and tended to increase (P < .19) Na and decrease (P < .12) K concentrations in the urine.

Effects of organic zinc supplementation in weaned calves

“…Their dams were supplemented pre partum with vitamins A, D, and E. In our study a significant positive correlation between serum Zn and serum total Ig concentrations was demonstrated. Engle et al (1997) reported a more pronounced cell response in marginally Zn deficient calves supplemented with Zn-Met and Zn-Lys than in calves supplemented with ZnSO 4 . Nemec et al (2014) reported a greater improvement of the immune status in lactating cows receiving organic Zn compared to those supplemented with inorganic Zn, Cu, and Mn sources.…”

Micronutrients and immune function in cattle

“…In young calves the addition of 150 or 3 00mg Zn/kg to a control diet containing 65 mg Zn/kg did not affect mitogen-induced blastogenesis, cytotoxicity and IL-2 production by lymphocytes, or phagocytic and bactericidal activity of isolated neutrophils (Kincaid et al 1997). Calves receiving 17 mg Zn/kg diet had a reduced induration response to intradermal injection of PHA compared with Zn-supplemented animals (Engle et al 1997).…”

Concentração do zinco sérico em vacas leiteiras suplementadas com Saccharomyces cerevisiae, portadoras ou não de lesões podais

“…Valores médios obtidos para as concentrações de zinco nos soros (µg/mL) nos grupos suplementados (G1 e G2) e controle (G3) nos diferentes dias ( 0, 90 e 180). Engle et al (1997), ao afirmarem que as fontes de zinco (orgânico e inorgânico) não afetaram as concentrações do zinco plasmático em seu estudo. Entretanto, quando bezerros foram suplementados com 500 mg de zinco/ kg, o zinco orgânico teve uma melhor absorção do que o zinco inorgânico, baseado, sobretudo nas maiores concentrações de zinco no plasma, fígado, duodeno e rins (WRIGHT; SPEARS, 2004).…”

“…Entretanto, quando bezerros foram suplementados com 500 mg de zinco/ kg, o zinco orgânico teve uma melhor absorção do que o zinco inorgânico, baseado, sobretudo nas maiores concentrações de zinco no plasma, fígado, duodeno e rins (WRIGHT; SPEARS, 2004). Engle et al (1997), registraram os valores de concentração de zinco sangüíneo entre 0,82 ±0,10 µg/mL e 1,07 ±0,38 µg/mL, e concluíram que dietas deficientes de zinco não afetam as concentrações no plasma e fígado de bezerros.…”