Dietart Copper, Manganese, Zinc Requirements And Bioavailability Of Two Zinc Sources For Juvenile Spotted Babylon, Babylonia Areloate

The present study was performed to investigate the effects of dietary copper(Cu),manganese(Mn), zinc(Zn) level or Zn sources on the growth performance, bodycomposition and non-specific immunity responses of juvenile spotted babylon,Babylonia areolate. The results can be summarized as follows:(1) The aim of this study was to examine the effect of copper level on the growth,survival, feed conversion (FCR), protein efficiency ratio (PER), soft body to shellratio (SB/SR), body composition and the non-specific immune responses of juvenilespotted babylon, Babylonia areolate. Seven purified diet containing graded levels ofdietary copper(1.2,2.1,3.9,6.2,9.0,13.4,20.5mg/kg) from CuSO4·5H2O were fed tojuvenile spotted babylon (initial body weight:176.29±0.83mg; initial shell length:9.43±0.03mm; initial shell width:6.01±0.04mm) in triplicate groups for8weeks. TheCu concentration in rearing water was2.91μg Cu/L. The results showed that theweigh gain rate (WGR), shell length increment rate (SLIR), shell width incrementrate (SWIR), survival, FCR, PER, SB/SR and body composition of spotted babylonwere not significant differences among the dietary treatments (P>0.05). The activitiesof T-SOD, Cu-ZnSOD, CAT and Cu-ATPase in soft body were significant increasedwhen supplementation of dietary Cu reached6.2,3.9,6.2,6.2mg/kg and decreasedwhen continue to supplement Cu. The soft body copper concentration was generallyincreased with the supplementation of dietary Cu (P<0.05), but the shell copperconcentration was not significantly affected by the dietary copper level (P>0.05).Analyzed by broken-line of T-SOD, CAT and Cu-ATPase activity and second-orderpolynomial regression of Cu-ZnSOD activity of soft body indicated that the optimumrequirement of juvenile spotted babylon for dietary Cu was4-6mg/kg diet.(2) This study aimed to evaluate the effects of Manganese (Mn) on the growth,survival, FCR, PER, SB/SR, body composition and the non-specific immuneresponses of juvenile spotted babylon, Babylonia areolate. Seven purified dietcontaining graded levels of dietary manganese (2.42,3.25,4.83,6.90,8.98,12.7,19.2 mg/kg) from MnSO4·H2O were fed to juvenile spotted babylon (initial body weight:175.25±0.54mg, initial shell length:9.43±0.04mm, initial shell width:6.02±0.03mm)in triplicate groups for8weeks. The Mn concentration in rearing water was5.5μg/L.The results showed that the growth, FCR and PER of spotted babylon were significantdifferences among treatments (P<0.05). The survival, SB/SR and carcass compositionwere not significantly differences among the treatments (P>0.05). Significantdifferences were found in the total superoxide dismutase (T-SOD) and manganesesuperoxide dismutase (MnSOD) activities among treatments (P<0.05). The activitiesof T-SOD and MnSOD in soft body were significant increased when supplementationof dietary Mn reached9.1mg/kg and decreased with the increasing dietary Mn level.The soft body Mn concentration was generally increased (P<0.05) and the shell Mnwas not signigicantly affected (P>0.05) with the supplementation of dietary Mn.Using the broken-line model with growth as the dependent variables, the dietary Mnrequirement of spotted babylon was estimated to be5.0mg/kg. Based on theenzymatic date, the dietary Mn requirement was determined to be approximately9.1mg/kg. Analyzed by second-order polynomial regression of soft body Mnconcentration, the optimum requirement of spotted babylon for dietary Mn was11.21mg/kg.(3)8weeks feeding experiment was conducted with juvenile spotted babylon(Babylonia areolate) fed purified diets supplemented with different zinc sources toevaluate the growth performance, nonspecific immunity enzymes activities (AKP,SOD, CuZnSOD and CAT) and zinc concentration in soft body of spotted babylon.The relative bioavailability value (RBV) of zinc in the supplemental sources testedwas also calculated. Purified experimental diets, which added0,5,10,20,30,50mg/kg zinc, provided as either zinc-methionine (ZnMet) or zinc sulfate (ZnSO4) fedto juvenile spotted babylon (initial body weight:106.25±0.00mg， initial shelllength:8.20±0.13mm, initial shell width:5.33±0.10mm) in triplicate groups. The Znconcentration in rearing water was5.74μg/L. The result showed that the WGR andsoft-body nonspecific immunity enzymes activity of the spotted babylon weresignificantly affected by dietary treatment (P<0.05), and responded in broken-linemodels to increasing dietary zinc levels from the two zinc sources. The requirementsfor dietary zinc using ZnMet and ZnSO4as the supplemental zinc sources, determinedby broken-line regression analysis, on the basis of maximum WGR were11.3and15.3mg/kg, respectively; on maximum T-SOD, Cu-ZnSOD, AKP, CAT enzymes activities were16-18mg/kg for ZnMet and22-25mg/kg for ZnSO4, respectively. Thesoft body zinc concentrations were generally increased with the supplementation ofdietary zinc from ZnMet and ZnSO4, and the concentrations were significantdifferences (P<0.05), but the shell zinc concentrations were not significantly affectedby zinc sources and zinc level (P>0.05). The survival, FCR, PER, SB/SR and bodycomposition of spotted babylon were not significant differences among the dietarytreatments (P>0.05). The RBV of ZnMet, with ZnSO4as the standard, were264%forWGR,267.8%and170.9%for SLIR and SWIR，for106%for soft body zincconcentration and107%，125%，135%and223%for T-SOD, Cu-ZnSOD, CAT andAKP activities. Average RBV of ZnMet was175%, showed higher than ZnSO4.