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M. F. MAGALHÃES C. E. RAMALHO & M. J. COLLARES-PEREIRA 《Fisheries Management and Ecology》2008,15(4):273-289
Abstract Biological indicators for Mediterranean rivers are poorly developed. This study evaluates the effectiveness of the Index of Biotic Integrity approach (IBI) with fish assemblages in the Guadiana catchment, a typical Mediterranean watershed in Southern Portugal. Reference sites were selected from a set of 95 sites, using a multivariate approach. Fifty-five candidate metrics were screened for range, responsiveness, precision and redundancy. Final metrics included: proportion of native fish, number of intolerant and intermediate species, number of invertivore native fish, number of phyto-lithophilic and polyphilic species, and catches of exotics. The IBI scores correlated with composite gradients of human impact and differed significantly between reference and non-reference sites. Application of the IBI to an independent validation set with 123 sites produced results congruent with the development set and repeatable assessments at 22 sites showed concordance in IBI scoring. This application highlights the effectiveness of the IBI approach even with fish assemblages of limited diversity and ecological specialisation as in Mediterranean streams. 相似文献
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M.V. DO CARMO E SÁ L.E. PEZZATO M.M. BARROS & P. DE MAGALHÃES PADILHA 《Aquaculture Nutrition》2005,11(4):273-281
A 90‐day feeding experiment was conducted with sex reversed Nile tilapia (Oreochromis niloticus) fingerlings fed purified or practical diets supplemented with different zinc sources to evaluate fish growth performance and zinc and iron retention in fish bones, fillets, liver, skin and eyes. The relative bioavailability value (RBV) of zinc in the supplemental sources tested was also calculated. Fish were fed with isonitrogenous and isoenergetic purified or practical diets supplemented with 150 mg Zn kg?1, as zinc sulphate monohydrate (ZnSO4), zinc oxide (ZnO) or zinc amino acid complex (Zn‐AA). The feeding trial was conducted in 30, 50 L aquaria where four 0.66 ± 0.01 g (mean ± SD) fingerlings were initially stocked. No significant differences were observed for any growth performance variables (P > 0.05). In practical diets, only ZnSO4 and ZnO presented bone zinc retention similar to that for the standard zinc source. Zinc concentration in the bone of fish fed practical diet supplemented with Zn‐AA (171 ± 3.62 μg g?1) was significantly lower than that verified for the practical diets supplemented with the standard zinc source (200 ± 17.7 μg g?1) or with ZnSO4 (204 ± 19.9 μg g?1). Assuming the concentration of zinc in bones as the response criterion, the supplemental zinc RBV from ZnSO4 (105%) was higher than the RBV for Zn‐AA (95.1%) or ZnO (94.9%). Iron concentration in the bones of animals fed the non‐zinc‐supplemented purified diet was significantly higher than that observed for purified diet supplemented with Zn‐AA (P < 0,05). The results of the present work allowed us to conclude that ZnSO4 in relation to ZnO or Zn‐AA was the supplemental zinc source with higher zinc bioavailability to Nile tilapia. 相似文献
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The investigations were carried out on a total of 70 cows with puerperal endometritis. In addition to intrauterine antibiotic treatment, 30 experimental animals were administered 20 μg GnRH analogue, buserelin, between days 10 and 12 post‐partum followed by 500 μg PGF2α analogue, cloprostenol, 10 days later. Forty control cows were treated only with intrauterine antibiotics. Blood samples for progesterone determination were collected from the tail vein twice weekly until day 70 post‐partum. The first rise in progesterone level above 3.18 nmol/l occurred significantly earlier in the experimental than in control cows (21.6 ± 9.2 versus 27.8 ± 12.3 days; p ≤ 0.05). The duration of the first cycle post‐partum was 15.0 ± 4.3 days in experimental and 19.7 ± 7.3 days in control animals (p ≤ 0.05). However, no significant differences were observed in the occurrence of first oestrus post‐partum. The involution of the uterus was improved after hormone treatment. At day 42 post‐partum, completion of uterine involution was found in 93.3% of hormone‐treated cows and in 82.5% of those treated with antibiotic only (p ≤ 0.05). Clinical recovery was 96.6% in the experimental and 82.5% in the control group (p ≤ 0.05). First service pregnancy rate was significantly better in hormone‐treated than control cows (51.7 versus 36.4%; p ≤ 0.05). Total pregnancy rate and insemination index values were not significantly improved following GnRH and PGF2α treatment. The average service period was 89.8 ± 21.2 days in cows after hormone treatment, and 112.6 ± 24.5 days in control cows. The difference was statistically significant (p ≤ 0.05). These results indicate, that the sequential GnRH and PGF2α application in cows with puerperal endometritis positively affected ovarian function and uterine involution, resulting in improved fertility performance. 相似文献
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MHB Santos MC Rabelo SI Guido JNC Torreão ES Lopes Júnior VJF Freitas PF de Lima MAL Oliveira 《Reproduction in domestic animals》2007,42(2):214-217
The aim of this study was to determine the period of genital tubercle (GT) migration using ultrasonography in Morada Nova sheep foetuses (n = 117) from natural mating (NM) and frozen embryo transfer (ET) to determine the window when foetal sexing can be determined. The examinations were performed using transrectal ultrasonography with a dual-frequency linear transducer (6.0 and 8.0 MHz) from day 30-54 of pregnancy at 48-h intervals. The period of GT migration of foetuses produced by NM varied from 36 to 46 days of pregnancy, resulting in an average of 39.5 +/- 2.9 days. For foetuses derived from ET, GT migration varied from 42 to 52 days of pregnancy with an average of 48.5 +/- 3.3 days, being possible the GT of foetuses from ET start to migrate 96 h later even if they are of the same gender. Migration of the GT occurred earlier (p < 0.05) in foetuses produced by NM and sexing accuracy for triplet pregnancies (77.8%) was significantly inferior (p < 0.05) to single (100%) and twin (92.9%) pregnancies for foetuses derived by NM. The results allow one to conclude that foetal sexing can be done from the 50th day onwards in foetuses produced by NM and from the 55th day onwards in foetuses derived from ET, and that multiple pregnancies compromise the sexing accuracy by ultrasonography. 相似文献
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The diagnostic value of the cement gland and other abdominal structures in aleyrodid taxonomy 总被引:1,自引:0,他引:1
J. M. GUIMARÃES 《EPPO Bulletin》1996,26(2):413-419
The morphological characters on which the taxonomy of the Aleyrodidae is based are found in the last instar larvae (pupae). Since in many situations only adults are available (as in sticky trap catches), difficulties may arise if specific determination is needed. In fact, the information given by the vasiform structure of adults and the male genitalia is not always conclusive. In the course of the present study, two sources of useful information were found in the female abdomen, namely the morphology of the cement gland and the setal pattern of the gonapophyses. Both structures can easily be examined by light microscopy, with a simple method of preparation. These characters (mainly those concerning the cement gland) have been consistent enough to allow identification of the main whitefly pest species in Portugal. An identification key mostly based on these structures is presented for Aleurothrixus floccosus, Aleyrodes proletella, Bemisia tabaci, Parabemisia myricae, Siphoninus phillyreae, Trialeurodes vaporariorum and Dialeurodes citri (this last not yet found in Portugal). 相似文献
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The formation of CH3 ONO in 11 soils treated with HNO2 or NaNO2 in a closed system, was studied by measuring the concentration in the gas space above the soil and by absorbing CH3 ONO in HI. The gaseous concentration of CH3 ONO increased and then decreased following additions of HNO2 or NaNO2 , and the production of CH3 ONO increased with increasing concentrations of HNO2 or NaNO2 added to soils.
The amounts of CH3 ONO trapped in HI were 13.5 to 20.4 times higher than those determined by integrating under the net production curves. The evolved CH3 ONO amounted to 0.4 to 3.5% of added NO2 − , and 4.2 to 50% of the gaseous forms of N absorbed by acidic KMnO4 solution. The CH3 ONO evolved from soils was positively correlated with the methoxy content of the soils, and inversely related to soil pH, with negligible amounts being evolved from alkaline soils. The results show that CH3 ONO is a product of NO2 − decomposition in soils, and indicate that small concentrations of the gas may be produced in N–fertilized soils in which NO2 − accumulates. 相似文献
The amounts of CH
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