Effects of organic plant oils and role of oxidation on nutrient utilization in juvenile rainbow trout (Oncorhynchus mykiss)

The study compared the effect of four either fresh or force oxidized organic plant oils in diets for juvenile rainbow trout (Oncorhynchus mykiss) in which 47% of conventional LT fish meal protein was substituted by a mixture of 3 organic plant protein concentrates. Fish oil was completely substituted with either organic linseed oil; rape seed oil; sunflower oil or grape seed oil and evaluated based on feed intake, feed utilization, growth and digestibility. None of the plant oils affected feed intake and growth parameters. Organic plant oils had all a positive effect on lipid digestibility as compared with the fish oil based control diet, despite the very different FA profiles. The organic vegetable oils did not undergo autoxidation, as opposed to the fish oil control for which lipid digestibility was significantly negative influenced

Different grain grinding methods affect detection of Fusarium graminearum DNA and mycotoxins

Fusarium graminearum is the most important deoxynivalenol (DON) producing species in northern Europe and Asia. The highest DON levels in Finland have been found in oat grain, and DNA levels of F. graminearum are in agreement with DON levels, when DON is measured by accredited GC-MS. In addition to DON, 3ADON is present in Finnish grain samples. Large variations in DON content and amounts of F graminearum DNA, and poor coefficient of determination (R-2) between these, have been detected in oat grain when the RIDA (R) QUICKSCAN kit results for DON content have been used. This study confirmed that the coefficient of determination was usually less when DNA or DON were extracted from oat flour, which was not ground with 0.8 mm or 1 mm sieves. DON levels obtained with the Rida Quick method were usually higher than those obtained with accredited GC-MS in Finnish oat, barley and wheat samples. The homogenization of the oat flour by sieving is therefore likely to be connected to the variations in DON detection. Amounts of F graminearum DNA and DON close to legislative limits should be reconfirmed with accredited quantitative analyses

Modeling the role of the close- range effect and environmental variables in the occurrence and spread of Phragmites australis in four sites on the Finnish coast of the Gulf of Finland and the Archipelago Sea

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The influence of macrophytes on sediment resuspension and the effect of associated nutrients in a shallow and large lake (Lake Taihu, China)

A yearlong campaign to examine sediment resuspension was conducted in large, shallow and eutrophic Lake Taihu, China, to investigate the influence of vegetation on sediment resuspension and its nutrient effects. The study was conducted at 6 sites located in both phytoplankton-dominated zone and macrophyte-dominated zone of the lake, lasting for a total of 13 months, with collections made at two-week intervals. Sediment resuspension in Taihu, with a two-week high average rate of 1771 g.m(-2).d(-1) and a yearly average rate of 377 g.m(-2).d(-1), is much stronger than in many other lakes worldwide, as Taihu is quite shallow and contains a long fetch. The occurrence of macrophytes, however, provided quite strong abatement of sediment resuspension, which may reduce the sediment resuspension rate up to 29-fold. The contribution of nitrogen and phosphorus to the water column from sediment resuspension was estimated as 0.34 mg.L-1 and 0.051 mg.L-1 in the phytoplankton-dominated zone. Sediment resuspension also largely reduced transparency and then stimulated phytoplankton growth. Therefore, sediment resuspension may be one of the most important factors delaying the recovery of eutrophic Lake Taihu, and the influence of sediment resuspension on water quality must also be taken into account by the lake managers when they determine the restoration target.Peer reviewe