| Summary: | 碩士 === 國立嘉義大學 === 動物科學系研究所 === 103 === Zinc is an essential micro mineral of animals. Zinc is a cofactor of metalloenzymes and hormones, and do as a growth promoter. Thus, it is common practice added high level of Zn in dietary for beneficial feeding effective of piglets and chickens, but also excrete high amount of zinc into the environment, cause serious pollution. Digestion is a process of degrading large molecules into smaller ones; using nanotechnology can reduce the material particles size, increase the surface area, hence improve its absorption, and also reduce the excretion and supplemental amount. Moreover, γ-poly-glutamic acid (γ-PGA, a polymer) can chelate with ions to improve minerals absorption and utility. Therefore, this study is aimed to investigate the effects of dietary supplementation of nanoparticle ZnO mixed with γ-PGA on zinc absorption, egg quality, production and serum traits in weanling piglets and aged layers. Trial 1, 48 weanling piglets (Average wiehgt was 8.31kg) were used in a 60-d trial. The dietary treatments were: (1) Control; (2) ZnO; (3) Organic Zn (Zn-methionine); (4) γ-PGA+NanoZn (2g/kg of 8% PGA). Trial 2, a total of 75 old layers (64-weeks of age) were used in a 60-d trial. The experimental diets were above mentioned four groups plus one group added NanoZn. Another 20 layers were used in a metabolic trial. The supplemental zinc were 120 mg/kg and 80 mg/kg in piglets and layers diets, respectively. The results show that piglets fed γ-PGA+NanoZn had significantly highest feed efficiency and serum growth hormone concentration than other groups, and serum ghrelin, carbonic anhydrase and γ-globulin level were higher in γ-PGA+NanoZn group than control group (P<0.05), organicZn and γ-PGA+NanoZn groups had higher GRBC antibody titers and serum zinc concentration (P<0.05). In zinc digestibility, γ-PGA+NanoZn group was better than control group (P<0.05), while ash and dry matter were no difference between groups. In aged layers results, no matter with or without γ-PGA, groups contained NanoZn were higher than control in ADFI (P<0.05), and greater than other treatments in serum zinc concentration. Eggshell zinc concentration was significantly higher in groups contained nanosize zinc than in other groups (P<0.05). Eggshell thickness, yolk and albumen index were significantly higher in the supplemented γ-PGA+NanoZn group than in the control group (P<0.05), as well as in the serum ghrelin and IgG levels, while carbonic anhydrase activity was higher than control, and metallothionein was greater than ZnO group (P<0.05). In zinc and ash retention, layer fed γ-PGA+NanoZn group was significantly higher than other groups (P<0.05), except organicZn group. Overall, nanosized ZnO mixed with γ-PGA can enhance zinc absorption, and displayed beneficial feeding effective in piglets and aged layers as compare to control and ZnO.
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