Mixing and scale affect moving bed biofilm reactor (MBBR) performance

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Estimating Breeding Values With Molecular Relatedness and Reconstructed Pedigrees in Natural Mating Populations of Common Sole, Solea Solea

Captive populations where natural mating in groups is used to obtain offspring typically yield unbalanced population structures with highly skewed parental contributions and unknown pedigrees. Consequently, for genetic parameter estimation, relationships need to be reconstructed or estimated using DNA marker data. With missing parents and natural mating groups, commonly used pedigree reconstruction methods are not accurate and lead to loss of data. Relatedness estimators, however, infer relationships between all animals sampled. In this study, we compared a pedigree relatedness method and a relatedness estimator (“molecular relatedness”) method using accuracy of estimated breeding values. A commercial data set of common sole, Solea solea, with 51 parents and 1953 offspring (“full data set”) was used. Due to missing parents, for 1338 offspring, a pedigree could be reconstructed with 10 microsatellite markers (“reduced data set”). Cross-validation of both methods using the reduced data set showed an accuracy of estimated breeding values of 0.54 with pedigree reconstruction and 0.55 with molecular relatedness. Accuracy of estimated breeding values increased to 0.60 when applying molecular relatedness to the full data set. Our results indicate that pedigree reconstruction and molecular relatedness predict breeding values equally well in a population with skewed contributions to families. This is probably due to the presence of few large full-sib families. However, unlike methods with pedigree reconstruction, molecular relatedness methods ensure availability of all genotyped selection candidates, which results in higher accuracy of breeding value estimation

Toxicity Effects of Cadmium in Grass Carp (Ctenopharyngodon idella) and Big Head Carp (Hypophthalmichthys nobilis)

Heavy metals can threaten ecosystem health and of food security. The purpose of percent study was evaluating the sensitivity of grass carp (Ctenopharyngodon idella) and Big head carp (Hypophthalmichthys nobilis) exposed to cadmium Chloride. To this end, fishes were exposed different concentrations of cadmium in range of cadmium chloride (0, 0.2, 1, 2, 6, 10 and 15 ml/l). The mortality of treatments was calculated at intervals of 24, 48, 72, 96 hours. Analysis of the data showed the 96 h LC50 of cadmium chloride for grass carp was 4.164 ml/l and for Big head carp was 5.590 ml/l. The results of this study showed that Cadmium is highly toxic for freshwater species