Bioavailability of two sources of zinc in weanling pigs

Animal Research, Jul 2002

Jean-Yves Dourmad, François Guinotte, Yves Nys

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Bioavailability of two sources of zinc in weanling pigs

Anim. Res. Bioavailability of two sources of zinc in weanling pigs Pierre-Stéphane REVY 0 2 Catherine JONDREVILLE 2 Jean-Yves DOURMAD 2 François GUINOTTE 0 Yves NYS 1 0 Calcialiment, ZI de la gare , 22690 Pleudihen , France 1 Institut National de la Recherche Agronomique, Station de Recherches Avicoles , 37380 Nouzilly , France 2 Institut National de la Recherche Agronomique, Unité Mixte de Recherches sur le Veau et le Porc , 35590 Saint-Gilles , France - Thirty-two pigs, weaned at 28 days of age with an average body weight of 9 kg, were used in an experiment devoted to the assessment of the bioavailability of an organic Zn source (ZnOrg) compared to Zn sulfate. Pigs were fed a basal diet containing 28 mg·kg-1 of Zn supplemented with ZnSO4 or ZnOrg to provide 0, 10, 20 and 30 mg·kg-1 of supplemental Zn. In order to reduce the amount and the variability of their Zn stores, pigs were fed the basal diet for a 7-day adjustment period preceding a 19-day experimental period. Growth performance and bone bending moment were not affected by the level nor the source of zinc. On the contrary, plasma zinc concentration and alkaline phosphatase activity (P < 0.001), bone zinc concentration (P < 0.001), liver and empty body zinc concentrations (P < 0.01) as well as the amount of Zn retained estimated both by the balance technique (BT) (P < 0.001) and by the comparative slaughter technique (CST) (P < 0.01) increased linearly in response to supplemental Zn. However, the two Zn sources exhibited a similar bioavailability. Twenty-seven percent of Zn intake was retained when measured by means of the balance technique, regardless of the dietary level or zinc source. Zn retention was 54% lower when measured by means of the CST as compared to the BT. - de croissance et le moment de flexion de l’os n’ont été affectés ni par le niveau ni par la source de zinc supplémentaire. Au contraire, la teneur en zinc et l’activité de la phosphatase alcaline du plasma (P < 0,001), les teneurs en zinc osseuse (P < 0,001), hépatique et corporelle (P < 0,01) ainsi que la quantité de zinc retenu estimée par la technique du bilan (P < 0,001) et celle des abattages comparés (P < 0,01) augmentaient linéairement avec l’addition du zinc. Cependant, aucune différence entre les sources n’a été détectée. Le coefficient de rétention de zinc, estimé par la technique du bilan, était de 27 % en moyenne, indépendamment du niveau ou de la source de zinc supplémentaire. Estimée par la technique des abattages comparés, la rétention de Zn était de 54 % inférieure à la valeur obtenue selon la technique du bilan. porc / zinc / biodisponibilité / source / indicateur 1. INTRODUCTION Zinc is an essential trace element which is involved in many metabolic functions. Zinc is a cofactor of more than 300 metalloenzymes and is required for at least one enzyme in all six enzyme classes [ 6 ]. Zinc deficiency in pigs is associated with parakeratosis, degraded growth performance (decreased food intake and weight gain) and diarrhea, particularly in young animals. Zinc requirements decrease from 100 to 50 mg·kg–1 diet when pig body weight increases from 5 to 50 kg and remain steady thereafter [ 19 ]. Such a dietary supply allows an optimal growth but also the maximization of zinc concentration in some tissues [ 36 ]. However, zinc contained in most plant feedstuffs is poorly available to chicks [ 20 ] and pigs [ 21 ], because it forms insoluble complexes with some organic ligands, mainly phytates. Therefore, the diets must be supplemented with zinc. In practice, because large safety margins are applied or because of their growth factor effect, zinc and other trace elements like copper are often oversupplied in pig diets and are highly concentrated in pig manure. Consequently, excessive zinc and copper accumulation in soils occurs in areas of intensive animal production, which may cause phytotoxicity of cultivated plants [ 8, 15, 27 ]. Because of this risk of environmental pollution, European regulation should move to a drastic reduction of maximal trace element concentrations authorized in pig diets. Zinc supplementation of pig diets can be achieved by means of different sources. Zinc sulfate (ZnSO4) and zinc oxide (ZnO) are commonly used in pig feeding. Organic (complexes or chelates) zinc sources have been suggested to exhibit a higher bioavailability in broilers than inorganic sources [ 33 ]. An enhanced bioavailability of organic Zn could allow the reduction of zinc supply in pig diets and, in turn, would contribute to environmental protection. A zinc-methionine complex exhibited a higher bioavailability (206%) than ZnSO4 in chicks fed corn-soybean meal diets [ 35 ]. In contrast, studies with pigs have failed to demonstrate differences in zinc bioavailability between organic and inorganic sources [ 7, 10, 34, 36 ]. This study was conducted to compare the bioavailability of zinc from an organic Zn source with that of ZnSO4, on the basis of a wide ra (...truncated)


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Jean-Yves Dourmad, François Guinotte, Yves Nys. Bioavailability of two sources of zinc in weanling pigs, Animal Research, 2002, pp. 315-326, Volume 51, Issue 4, DOI: doi:10.1051/animres:2002028