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131.
Individual size, size variability, cannibalism, total mortality and biomass production were studied in Clarias gariepinus in two experiments. In the Experiment 1st (duration 7 weeks) larvae originated from three females 1, 2 and 4 years old (females A, B and C, respectively). Three sibling (AA, BB and CC) and three mixed (AB, AC and BC, 1:1) larval groups were reared at a 12L:12D, 50 lux light regime. Initial individual weight of larvae in the sibling groups was strongly positively related to female age, this was preserved during 7 weeks of rearing. Initial coefficient of variation for weight was moderate in the sibling groups from young females AA and BB (30-33%), whereas it was elevated in the mixed groups (48-79%), especially in the group AC. Cannibalism was the major component of total mortality. Cannibalism in progeny of young females AA, AB and BB was reduced compared to the groups BC, AC and CC. Final biomass of small larvae issued from young females was higher than the final biomass of large progeny of the oldest female because of reduced cannibalism in the former. In a 6 week Experiment 2nd progeny of one female was reared at three light regimes: L (continuous light, 400 lux), N (“normal” 12L:12D, 50 lux) and D (continuous darkness). The final individual weight of fish was the lowest in the L group, highest in the D group, and intermediate in the N group. Final coefficient of variation for weight, cannibalism and total mortality were significantly reduced by light restrictions. The resulting final biomass was the lowest in the L group, intermediate in the N group and the highest in the D group in which it was higher by a factor 3.8 compared to the L group. Based on the results of present work and on literature overview several pathways were identified along which biomass size may be modified in populations of young fish that exhibit cannibalistic propensity. Selection of young female spawners of uniform age, and light restrictions, are recommended to mitigate cannibalism. 相似文献
132.
Zbigniew Kaczkowski Piotr Frankiewicz Aleksander Gralczyk 《Fisheries Management and Ecology》2019,26(3):187-199
The Pilica River has warmed at a rate of 0.06°C per year since 1969, threatening the ecological services provided by the Sulejów Reservoir. Gillnet sampling revealed that the reservoir is inhabited by a cyprinid‐dominated fish assemblage with roach, Rutilus rutilus (L.) (42% of the total biomass), the dominant species. However, the interest of the anglers was primarily focused on common bream, Abramis brama (L.) (almost 65% of the catch), as revealed by the catch statistics (2004–2014). No direct evidence was found that the temperature increase had an influence on the recreational fishery or fish assemblage structure. On the other hand, changes in the fish assemblage that were reflected in angler catch composition were observed. A decrease in the catch of common bream in gillnets was accompanied by a shift in angler choices towards roach and other fish species. The sustainability of recreational fisheries is more likely to be influenced by changes in the economic status of society, water quality (toxic cyanobacteria blooms) and water management practices in Poland. The question arises about which species will dominate in the impoundment in the future if the warming trend continues and common carp, Cyprinus carpio L., stocking is maintained. 相似文献
133.
Grzegorz J. Dietrich Mariola Dietrich Piotr Hliwa Robert Stabinski Joanna Nynca Aneta Andronowska Andrzej Ciereszko 《Fish physiology and biochemistry》2010,36(3):419-425
The objective of this study was to describe the morphometry and motility parameters of vendace (Coregonus albula) spermatozoa. Morphometric parameters of vendace sperm head and tail were of values similar to rainbow trout. The effects
of pH, sodium, potassium and calcium ion concentrations on computer-assisted sperm analysis (CASA) sperm motility characteristics
were tested. Vendace sperm was motile in a wide pH range of 6.0–10.5 with the optimum pH established at 9.0. Increases in
potassium and calcium ions caused decreases in the percentage of motile sperm. The CASA parameters and erratic sperm movement
pattern of vendace spermatozoa were similar to whitefish (C. lavaretus) sperm motility, suggesting that there is a coregonid-specific sperm motility pattern. 相似文献
134.
Probiotics, bacteria from the genera Bifidobacterium and Lactobacillus, and yeast, Saccharomyces, as well as prebiotics belonging to the group of dietary fiber (inulin with low degree of polymerization, fructose‐derived oligosaccharides, and resistant starch) are natural factors useful in prophylaxis and therapy of several common diseases including some types of cancer. They are available commercially and can be introduced to produce so‐called functional food. Probiotics and prebiotics can be utilized either separately or jointly (as synbiotics or eubiotics). Mechanisms of both biotics are discussed. The role of cereals in probiosis is considered. Possibilities for extension of the uses of the original Chinese probiotic, chaw tofu, are also considered. 相似文献
135.
136.
Radosław Jagiełło Grzegorz Iszkuło Piotr Karolewski Edward Baraniak Marian J. Giertych 《国际虫害防治杂志》2019,65(1):33-43
Defoliation caused annually by Cameraria ohridella has a considerable impact on the general condition of horse chestnut trees. We investigated the consequences of tree endotherapy against this insect. Wood samples, leaves and insect specimens were collected ten years after the treatment (injection) with pesticides. Insect invasion was manifested in all investigated trees by distinct radial growth depression. Treatment resulted in a growth upturn, while non-treated trees maintained decreased growth. The overall foliage infestation level was lower in treated trees, but pupal mass and potential fecundity of insect females were not affected. Our study revealed a long-lasting, positive effect of endotherapy on trees’ appearance and growth. 相似文献
137.
Emna Abdellatif Monika Kałużna Patrizia Ferrante Marco Scortichini Bochra Bahri Jaap D. Janse Johan van Vaerenberg Steve Baeyen Piotr Sobiczewski Ali Rhouma 《Plant pathology》2020,69(8):1414-1425
Citrus blast and black pit caused by Pseudomonas syringae pv. syringae (Pss) is the only bacterial disease reported in Tunisian Citrus orchards. The phylogenetic relationship between Pss strains was studied based on multilocus sequence analysis (MLSA), using partial sequences of housekeeping genes rpoD, rpoB, gyrB, cts, and pfk for 14 representative Pss Citrus strains, including the reference strain LMG5496. The MLSA revealed that the studied Tunisian Citrus strains are closely related to LMG5496 and cluster in phylogroup 02. Based on the cts gene, the majority of Citrus strains clustered in clades “a” and “b”. However, five strains were placed in a newly defined clade “g”. We describe the presence of six different type III secreted effectors (T3SEs). These were found with frequencies of 100% for the effector hopAN1 and the helper hrpK1, 65% for hopT1-2, and 14% for hopN1, hopR1, and hopQ1-2. Investigation of copper resistance showed that 67% of our Pss Citrus strains from Tunisia are resistant to copper sulphate in vitro, and the copper resistance genes copABCDR were detected in 23% of the strains. Our results present new data concerning the genetic diversity and phylogeny, presence of T3SEs, and copper resistance within the Pss populations that affect Citrus in Tunisia. 相似文献
138.
Effect of Li, Al, Cd, Cu(II), Mn(II), Pb(II), Se(IV) and Zn on entomopathogenic nematodes S. carpocapsae and H. bacteriophora mortality, pathogenicity, and productivity was studied under laboratory conditions. These ions were administered as the sole ions as well as in the Li-Al, Li-Cd, Li-Cu(II), Li-Mn(II), Li-Pb(II), Li-Se(IV) and Li-Zn pairs. Lithium as the sole acting ion exhibited a weak lethal effect on the nematodes. In combinations with other metal ions under study lithium used to inhibit their harmful effects. 相似文献
139.
Metapopulation and optimal foraging theories predict the presence of animals and their duration, respectively, in foraging
patches. This paper examines use of these two theories to describe the movements and patterns of foraging in patches used
by Caspian gulls (Larus
cachinnans) at inland reservoirs during the chick-rearing period. We assumed that birds would move differently across diverse habitats,
with some types of land cover less permeable than others, and some landscape features acting as corridors. We also expected
larger and less isolated patches, and patches that were close to corridors, to have a higher probability of the presence of
foraging birds, and that they would be more abundant, forage for a shorter time, and hunt smaller prey than in small, more
isolated patches surrounded by barriers. Forests seem to be a much less permeable type of land cover, whereas rivers became
corridors for Caspian gulls during foraging trips. Probability of bird presence was positively related to the size of foraging
patches and negatively linked with distance to the nearest river, distance to the nearest foraging patch, and the presence
of forests in the vicinity. The same factors significantly affected bird abundance. Contrary to expectations, the duration
and success of foraging were not influenced by any variable we measured, suggesting that although larger patches contain a
higher abundance of fish, their density and the probability of capturing prey were relatively stable among the various patches.
However, gulls that foraged in more isolated ponds that were located further from the river and the colony, and also surrounded
by forest, captured larger fish more often than birds that foraged near the colony in less-isolated patches. Pooling metapopulation
and optimal foraging concepts seems to be valuable in describing patch use by foraging animals.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
140.
Teresa Ostaszewska Konrad Dabrowski Piotr Hliwa Piotr Gomóka & Karolina Kwasek 《Aquaculture Research》2008,39(12):1268-1278
The present study includes the evaluation of morphological changes in the digestive tract of larval, stomachless fish silver bream ( Vimba vimba ) fed with various diets – live Artemia nauplii, commercial feed Aglo Norse (NOR) and semi-purified formulated diets: casein–gelatin (CG), dipeptide-protein (50P), dipeptide (100P), no-arginine dipeptide diet (100Pw/oArg) and a free amino acid (FAA) mixture diet. The supranuclear area of enterocytes in the posterior intestine contained enlarged absorptive vacuoles in the FAA, 100P and 100Pw/oArg groups, compared with the remaining groups. Hepatocytes' cytoplasm in fish fed with FAA, 100P and 100Pw/oArg contained mainly glycogen, and no lipid vacuoles were found. Fish fed with 100Pw/oArg showed the lowest hepatocyte surface areas while in those fed with 50P, the largest nuclei diameters were observed. Fish fed with Artemia , NOR and CG diets showed significantly ( P <0.05) higher number of proliferating cells compared with the remaining groups. Chromogranin A staining showed endocrine-immunoreactive cells (CgA-IR) in the taste buds in the oral cavity and in the enterocytes' supranuclear areas of the anterior and posterior intestine. We conclude that the growth rate and histological examination of the digestive tract in the 50P group of silver bream showed no nutritional deficiency. 相似文献