Growth-promoting efficacy in young pigs of two sources of zinc oxide having either a high or a low bioavailability of zinc.

Abstract

Commercial sources of zinc oxide (ZnO) differ widely in Zn relative bioavailability (RBV), but it is unknown whether growth-promoting efficacy in young pigs is influenced by RBV of the ZnO sources used. We compared a low-RBV (39%) ZnO manufactured by the Waelz process (W) to a high-RBV (93%) ZnO manufactured by the hydrosulfide process (HS). Antibacterial agents were included in the diet in only one of the four trials (Exp. 4). In Exp. 1, pigs (n = 36, 6.5 kg, 28 d of age) were randomly assigned in three replicates to receive 0, 1,500, or 3,000 mg Zn/kg from HS Zn in a 21-d growth assay. Growth rates and feed intake responded linearly (P < 0.01) to incremental doses of Zn. In Exp. 2, pigs (n = 60, 6.1 kg, 28 d of age) were randomly assigned in five replicates to receive either 0 or 1,500 mg W or HS Zn/kg during a 21-d feeding period. Growth performance was improved (P < 0.01) by the addition of ZnO. During wk 1, however, pigs receiving HS Zn grew faster (P < 0.03) than those receiving W Zn, but the difference diminished to a trend (P < 0.08) during wk 2. Morphology of duodenal, jejunal, and ileal intestinal sections was examined at d 21 of the assay, but neither source of ZnO had an effect on crypt depth or on villus height or width. In Exp. 3, weaned pigs (n = 48, 5.4 kg, 21 d of age) were randomly assigned in four replicates to the same dietary treatments as in Exp. 2 for a 17-d growth assay. Growth performance was improved (P < 0.05) by the addition of ZnO, but no difference was detected between the two sources. In Exp. 4, pigs (n = 60, 6.2 kg, 28 d of age) were randomly assigned in five replicates to receive either 0 or 1,500 mg/kg W or HS Zn in an 11-d growth assay wherein antimicrobial agents were included in the basal diet. Growth rates during the first 6-d were improved (P < 0.06) by the addition of ZnO, with a trend (P < 0.10) for greater weight gain in pigs receiving HS than in those fed W Zn. During the entire 11-d, however, there was no difference in growth rates between pigs fed the two sources of ZnO. In conclusion, RBV of Zn in ZnO did not substantially affect the growth-promoting efficacy of ZnO in young pigs fed diets with or without antimicrobial agents.

Low doses of microencapsulated zinc oxide improve performance and modulate the ileum architecture, inflammatory cytokines and tight junctions expression of weaned pigs

“…The widespread diffusion of ZnO in medicated premixes in the EU, although regionally different as certain countries are not allowed to use it, whereas others are allowed to extend its use over 6 weeks post-weaning, has posed a threat from an environmental perspective, as the major part of ingested ZnO appears to be excreted with the feces (Poulsen and Larsen, 1995;Mavromichalis et al, 2000). Zinc oxide mechanism of action as growth promoter appears to go beyond the fulfillment of Zn nutritional needs, and it seems to be more related to improved intestinal health (Zhang and Guo, 2009).…”

Leitões recém-desmamados alimentados com dietas contendo proteína láctea e zinco suplementar

“…Tabela 5 -Relação altura de vilosidade:profundidade de cripta (AV:PC) do duodeno e do jejuno ao 7º e 14º dias do período experimental Por outro lado, Mavromichalis et al (2000) relatam que a suplementação de ZnO na dieta de leitões não ameniza os efeitos negativos na mucosa intestinal. Todavia, para o zinco, via dieta, exercer suas funções biológicas é necessário que sua absorção seja facilitada.…”

“…O modo de ação do zinco e sua associação como promotor do crescimento em leitões jovens ainda é incerta (Mavromichalis et al, 2000). Carlson et al (1999) sugerem que a indução da metalotioneina nos enterócitos pode ser responsável para aumentar o crescimento animal sob doses farmacológicas de zinco.…”

“…Carlson et al (1999) sugerem que a indução da metalotioneina nos enterócitos pode ser responsável para aumentar o crescimento animal sob doses farmacológicas de zinco. A metalotioneina está envolvida na homeostase do zinco no intestino delgado e nos níveis sistêmicos e, assim, essa expressão é diretamente relacionada pela concentração de zinco (Mavromichalis et al, 2000 Tabela 8 -Pesos relativos do fígado e do intestino delgado ao 7º e 14º dias de experimento…”

Proteína láctea e zinco suplementar em dietas de leitões recém-desmamados

“…Por outro lado, Mavromichalis et al (2000) relatam que a suplementação de ZnO na dieta de leitões, não ameniza os efeitos negativos na mucosa intestinal. Todavia, para o zinco, via dieta, exercer suas funções biológicas, é necessário que sua absorção seja facilitada.…”