RESUMO
BACKGROUND: Our previous studies demonstrated that divalent organic iron (Fe) proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation (Qf) values displayed higher Fe bioavailabilities for broilers. Sodium iron ethylenediaminetetraacetate (NaFeEDTA) is a trivalent organic Fe source with the strongest chelating ligand EDTA. However, the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested. Herein, the chemical characteristics of 12 NaFeEDTA products were determined. Of these, one feed grade NaFeEDTA (Qf = 2.07 × 108), one food grade NaFeEDTA (Qf = 3.31 × 108), and one Fe proteinate with an extremely strong chelation strength (Fe-Prot ES, Qf value = 8,590) were selected. Their bioavailabilities relative to Fe sulfate (FeSO4·7H2O) for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance, hematological indices, Fe contents, activities and gene expressions of Fe-containing enzymes in various tissues of broilers. RESULTS: NaFeEDTA sources varied greatly in their chemical characteristics. Plasma Fe concentration (PI), transferrin saturation (TS), liver Fe content, succinate dehydrogenase (SDH) activities in liver, heart, and kidney, catalase (CAT) activity in liver, and SDH mRNA expressions in liver and kidney increased linearly (P < 0.05) with increasing levels of Fe supplementation. However, differences among Fe sources were detected (P < 0.05) only for PI, liver Fe content, CAT activity in liver, SDH activities in heart and kidney, and SDH mRNA expressions in liver and kidney. Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake, the average bioavailabilities of Fe-Prot ES, feed grade NaFeEDTA, and food grade NaFeEDTA relative to the inorganic FeSO4·7H2O (100%) for broilers were 139%, 155%, and 166%, respectively. CONCLUSIONS: The bioavailabilities of organic Fe sources relative to FeSO4·7H2O were closely related to their Qf values, and NaFeEDTA sources with higher Qf values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.
RESUMO
OBJECTIVE: To explore the immunosuppressive effect of local transfection of Molluscum contagiosum virus 148 (MC148) gene to allogenous skin graft against rejection. METHODS: MC148 gene was cloned from molluscum contagiosum virus (MCV), and was employed to construct recombinant adenovirus vector (Ad-MC148). The recombinant Ad-MC148 was then locally transfected into a part of the tail skin of eight Lewis rats, which served as skin donors for grafting. The wounds (1 cm x 1 cm) were produced on the tails of 16 Wistar rats, and they were then randomly divided into control (C, n=8, with grafting of skin from donor rats without transfection), and transfection (T, n=8, with grafting of skin from donor rats with transfection of the recombinant Ad-MC148) groups. The expression of MC148 mRNA gene in T group was detected on 6 post operation hour( POH) and 2, 3, 7 and 10 post operation day (POD), and the results were expressed by the ratio of absorption value (A) between MC148 gene and beta-actin. The survival time of skin grafts in both groups was compared. Gross examination of grafted skin was carried out from 7 POD on in both groups, and the pathomorphological changes were examined in both groups on 7 POD. RESULTS: The MC148 gene expression in rat skin of T group could be identified in 6 POH, and it reached the peak on 3 POD (A(MC148 mRNA) / A(beta_actin) = 0.86), and then subsided thereafter, but it maintained for 10 days. The survival time of the grafts in T group was (15.0 +/- 2.0) days, and it was significantly longer than that in C group (8.5 +/- 3.4) days, (P < 0.01). Gross and microscopic examination showed that the tail skin of T group appeared ruddy on 7 POD, with little leukocytic infiltration in subcutaneous tissue; it began to turn black after 12 to 20 PODs. On the other hand, the tail skin of C group began to turn black and to shed off on 7 POD, with evident leukocytic infiltration in subcutaneous tissue and dermis. CONCLUSION: Local transfection of MC148 gene may promote immunosuppression by inhibiting leukocytic infiltration after allogenous skin transplantation.