Vertical distribution of zooplankton in a shallow peatland pond: the limiting role of dissolved oxygen

We investigated the diel vertical distribution patterns of microcrustacean zooplankton (Cladocera, Copepoda) in a shallow pond (max. depth: 70 cm) of the Öreg-turján peatland (Ócsa, Central Hungary) during three 24-h periods in July (19–20th), August (17–18th) and September (11–12th) 2011. Environmental variables showed remarkable vertical stratification. Oxygen concentration was close to zero in the entire water column from night until sunrise, while the lower strata (from 20 cm below the surface) were close to anoxic during all three diel cycles. It proved to be the main determinant of the vertical distribution of microcrustaceans. Accordingly, the highest proportion of individuals was present in the surface layer. Chlorophyll-a concentration and phytoplankton biomass were inversely distributed compared to zooplankton. Microcrustaceans (mainly Daphnia curvirostris) migrated to the middle layer only in August, which could be explained by a trade-off between food resources, dissolved oxygen (DO) and competition with littoral zooplankters. The diurnal density patterns of microcrustaceans suggested horizontal migration into the aquatic macrophytes during night, which could be a strategy to avoid Chaoborus predation. Our results show that strong vertical gradients of abiotic and biotic factors occur even in such shallow waterbodies. Among them, DO can maintain constant vertical aggregation of zooplankters by limiting their occurrence to the surface layers

Epiphytic metazoans on emergent macrophytes in oxbow lakes of the Krapina River, Croatia: differences related to plant species and limnological conditions

This study investigated the structure of the epiphytic metazoans on emerged macrophytes in the littoral zone of two oxbow lakes with different trophic levels. Differences in the diversity and density of the epiphytic metazoans were analyzed in relation to plant architecture (simple or complex stems), food resources (algae and detritus) and water characteristics (transparency and derived trophic state index). Asignificant negative correlation was found between detritus on plants as food resource, and diversity and density of epiphytic metazoans, indicating grazing of microphagous species. Rotifers dominated in diversity and density in the epiphyton on all habitats. Total density of metazoans, rotifers and copepods in epiphyton were significantly higher on Mentha in mesotrophic lake than on Iris in a eutrophic lake.We presume that macrophyte belt width and trophic state governed biotic interactions and consequently epiphytic assemblages more strongly than macrophyte architecture. However, a Mentha habitat showed a slightly higher density and diversity of epiphytic metazoans in relation to Iris at the same site, but these differences were not significant

The content of bioactive components in milk depending on cow feeding model in certified ecological farms

Żywienie krów odgrywa kluczową rolę w kształtowaniu produkcyjności i jakości mleka. Celem badań było ustalenie wpływu różnych modeli żywienia krów utrzymywanych w certyfikowanych gospodarstwach ekologicznych województwa mazowieckiego na zawartość bioaktywnych składników mleka (BSM). Przeanalizowano żywienie oraz produkcyjność krów w dwóch sezonach żywienia: letnim i zimowym w 2010 roku w dwóch gospodarstwach specjalistycznych. W badanych gospodarstwach dawki żywieniowe w okresie letnim i zimowym różniły się rodzajem stosowanych pasz. Badania przeprowadzono na 20 krowach. W mleku oznaczono LKS, witaminy A, D3, E i K2, profil kwasów tłuszczowych, białka serwatkowe, Ca, P i Mg. Najlepsze efekty produkcyjne w gospodarstwach ekologicznych wykazano w sezonie żywienia letniego u krów wypasanych na pastwisku, dokarmianych sianokiszonką i paszą treściwą w gospodarstwie G1. Mleko krów pochodzące z sezonu żywienia letniego z gospodarstwa G2 wyróżniało się statystycznie wyższą zawartością składników o właściwościach antyoksydacyjnych, głównie ?-karotenu i witaminy D3 oraz CLA w porównaniu z mlekiem z sezonu żywienia zimowego, odpowiednio o 78% i 14% oraz 437%. Najwyższą koncentrację BSM w sezonie żywienia zimowego wykazano w mleku krów żywionych dawką z udziałem dyni pastewnej (G2).W trakcie trwania żywienia zimowego w mleku z gospodarstwa G2 vs. G1 wykazano większą zawartość ?-karotenu (0,355 vs. 0,195mg/l)i TAS-u (1,759 vs. 1,721 mmol/l), oraz bioaktywnych kwasów tłuszczowych takich, jak:CLA, TVA i LNA odpowiednio(0,946 vs. 0,381, 2,20 vs. 0,89 i 0,956 vs. 0,734 g/100g tłuszczu. Zawartość wielonienasyconych kwasów tłuszczowych (PUFA) w sezonie żywienia zimowego również była statystycznie wyższa w mleku w gospodarstwie G2 niż w G1 o 24,2%. Uzyskane wyniki wskazują na korzystniejszą jakość prozdrowotną mleka, które pochodzi od krów mających w dawce zimowej dynię pastewną, a w dawce letniej - od krów żywionych zielonką pastwiskową do woli.Cow feeding plays a crucial role in shaping of their productivity and milk quality. The aim of the research was to examine the influence of different feeding models for cows kept in certified ecological farms of Mazovian voivodeship on bioactive milk components (BMC). Cow feeding and productivity in two feeding seasons (summer and winter) in 2010 in two specialist farms were analyzed. In examined farms feeding rations differed in type of feedstuffs used. The experiment was carried out on 20 cows. Somatic cell count (SCC), vitamins A, D3, E and K2, fatty acids profile, whey proteins, Ca, P as well as Mg were determined in milk. The best productivity effects in ecological farms were proved in summer feeding season season in case of cows grazed in the pasture and additionally receiving hay silage and a concentrate at the farm G1. Cow milk collected during summer feeding season at the farm G2 had statistically higher content of antioxidant components, mainly ßcarotene and vitamin D3, as well as CLA comparing with milk collected in winter season by 78%, 14% and 437% respectively. In winter feeding season the highest BMC concentration was proved in milk of cows fed the ration containing fodder pumpkin (G2). During winter feeding, in milk from G2 vs. G1 farms, it was observed highest content of ß-carotene (0.355 vs. 0.195mg/l) and TAS (1.759 vs. 1.721 mmol/l) as well as bioactive fatty acids like CLA, TVA and LNA (0,946 vs. 0.381, 2.20 vs. 0.89 and 0.956 vs. 0.734 g/100g of fat respectively). The content of PUFA during winter feeding season was also statistically higher in milk from G2 than G1 farm by 24.2%. The results obtained show more health-profitable quality of milk from cows receiving fodder pumpkin in winter ration and the animals fed ad libitum pasture green forage in the summer

Porównanie wyników oceny użytkowości czystorasowej i mieszańcowej populacji bydła rasy hereford w Polsce

Comparison of recording results of purebred and crossbred Hereford cattle in Poland. The aim of the study was to compare purebred and crossbred Hereford cattle in respect to their compliance with the breeding goals and standards adopted by the Polish Association of Breeders and Producers of Beef Cattle. The study was based on data for the years 2002–2015 from the PABPBC and for the years 1996–2001 from the National Center of Animal Breeding (NCAB). The properties that were evaluated were the average body weight of calves after birth (kg), average daily weight gain of calves from birth to 210 days (g), average body weight of calves at 210 days (kg) and average milk yield of cows (kg). One can observe a gradual decline in the share of the national Hereford beef cattle population, it also shows a significant decrease in the number of crossbreds with Hereford breed. Purebred Hereford cows delivered calves about 2–3 kg heavier than calves from crossbreds ones. Higher birth weights, both within the purebred and hybrid population, had bulls. The difference between bulls and heifers was usually 2–3 kg depending on the assessment year. For both populations growing trend of bull calves body weight at birth could be observed. In case of heifers calves the growing trend was observed in purebred population only. the average daily weight gain of calves increased considerably in the last years of analysis. The presented data show that both pure-bred calves and hybrids were characterized by relatively high body weight gain in the rearing period. The average daily gain was 812–1002 g for pure-bred heifers and 852– –1045 g for pure-bred bulls and for crossbred heifers 876–1039 g and 889–1081 g for bulls

Susceptibility of hulled and hulless barley doubled haploids to Fusarium culmorum head blight

Fusarium culmorum (W.G.Sm.) Sacc. is a pathogen affecting seedling, head, root and stem of barley, and the infection can result in significantly reduction of yield and grain quality. The aim of the studies was to compare the susceptibility of hulless and hulled barley doubled haploids (DH) to infection with F. culmorum . Thirty DH lines (15 hulled and 15 hulless) and their parents were inoculated with a conidial suspension of the isolate of F. culmorum KF350 (IPO348-01) (nivalenol chemotype). Experiment was carried out over six years. Spike infection score, kernel weight per spike, 1000-kernel weight and percentage of plump kernels (>2.5 mm) were examined in control and inoculated plants. In addition, in three environments, nivalenol (NIV) accumulation in infected kernels was analysed. Significant influence of genotypes and environments on spike infection, yield-related traits and NIV accumulation was found in inoculated plants. Hulless genotypes appeared to be more susceptible to infection than the hulled lines. The difference in NIV accumulation was not important — mean NIV content over three environments was similar for both groups of DH lines. Results suggest that glumes adhered to seed may protect it, to a certain degree, against penetration of the pathogen inside the seed