Open Access Original Research Article

On the Environmental Impact of Freshwater Fish Farms in Greece and in Iceland

T. Mavraganis, H. Thorarensen, M. Tsoumani, C. Nathanailides

Annual Research & Review in Biology, Page 1-7
DOI: 10.9734/ARRB/2017/32426

In the present study, we focused on the nitrogen and phosphorus levels generated by open flow freshwater fish farms in Greece and Iceland where salmonid fish are cultivated. There are several differences in the legislation and regulation of the aquaculture sector in Greece and in Iceland. Nevertheless, in both countries, environmental protection agencies need accurate information for nutrient processes in order to evaluate the environmental influence on surrounding waters by salmon aquaculture. Data were collected from surveys of 21 freshwater fish farms in Greece and 9 in Iceland. The surveyed farms practiced intensive production methods. The concentrations of nitrogen and phosphorus in farms’ discharges were used to estimate organic load generated. The collected data were compared with data from the literature for the production Salmonids for species cultivated in Iceland (Arctic charr, Atlantic salmon) and in Greece (Rainbow trout). The results of the analysis indicate that in both countries the highest concentrations of nitrogen and phosphorus discharges of fish farms exhibits a variability which can be attributed to the total biomass of produced fish, fish feed and feeding management protocols used, species cultivated and ambient temperature. During the last 30 years, there was a significant reduction in the amount of nutrients generated by fish farms, which to a great extent is a result of lower levels of protein content in fish feeds and improved feed conversion efficiency. It is estimated that over the past 30 years, the combined effect of reduced nitrogen and phosphorus content and the improvements in Feed Conversion Efficiency, resulted in about 50% reduction in the nutrients generated by every Kg of farmed fish produced. Nevertheless, this significant improvement was easily offset by and increased production of fresh water fish farms exhibited in both countries. It seems possible that legislative measures combined with improvements in technology and feed management of fish farms will continue to be good option of minimizing the environmental impact of fish farms in the future.

Open Access Original Research Article

Screening Drought Tolerant Rapeseed Cultivars Using Yield and Physiological Indices

Bahlanes Bakhtari, Hooman Razi, Seyed Abdolreza Kazemeini

Annual Research & Review in Biology, Page 1-10
DOI: 10.9734/ARRB/2017/32938

Rapeseed (Brassica napus) is an important source of edible oil worldwide. Rapeseed production is adversely affected by water deficit stress in drought prone areas. This study aimed to evaluate drought tolerance in seventeen rapeseed cultivars using yield and physiological indicators. The field experiment using two irrigation regimes was conducted on a silty loam soil at the research station of School of Agriculture, Shiraz University, Shiraz, Iran. In each irrigation treatment, the seventeen rapeseed cultivars with different origins were grown in a randomized complete block design with three replications. The normal irrigation and drought stress treatments were irrigated when 40% and 70% of available soil water capacity were depleted, respectively. The results revealed highly significant differences among the rapeseed cultivars for seed yield, and the various yield and physiological indices. The yield under normal and drought stress conditions showed significant correlations with stress tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean productivity (HMP) and modified stress tolerance index (MSTI) implying these indicators are able to identify the high yielding drought tolerant rapeseed cultivars. Based on the reliable yield indices, the three-dimensional plot and biplot analysis showed that the cultivars Karaj 1, NK Octans and Modena were the high yielding drought tolerant rapeseed cultivars. Generally, the drought tolerant cultivars showed high relative water content (RWC) under stress conditions, however there was no strong association between drought tolerance and RWC.

Open Access Original Research Article

Influence of Weed Management Practices on Growth Parameters and Economics of Cowpea [Vigna unguiculata (L.) Wasp.]

Pravindra Kumar, Raghuveer Singh

Annual Research & Review in Biology, Page 1-9
DOI: 10.9734/ARRB/2017/33060

A field trial was carried out in the Kharif seasons 2007 at Junagadh Agriculture University (JAU), Junagadh, Gujarat to evaluate the impact of integrated approach of weed management on rain fed cowpea. It was found that selection of appropriate herbicides and its application in combination with cultural practices at critical period of weed growth was key factor to get elevated yield in rain fed cowpea. Till date most accepted practices among cowpea growers is single application of herbicides or go for cultural practices one hand weeding (HW) + one inter cultural (IC) at 20-25 days after sowing (DAS). This was not found sufficient to manage weeds and negatively distress the growth parameters and ultimately resulted in loss of one fourth crop yield compared to that weed free treatment. Application of (pendimethalin + 1 HW + 1 IC), (imazethapyr + 1 HW + 1 IC) and (quizalofop-ethyl + 1 HW + 1 IC)  very effective in weed control and had positive impact on plant height, plant spread, number of branch per plant, number of pods per plant and number of seeds per pods. These treatments were as good as weed free plot. These integrated weed management treatments gave broad spectrum weed control and higher gross, net return and B:C ratio. By adopting appropriate weed management practices farmer can get 3000 to 4000 net increase in return over the other treatment. So integrated weed management is better option and cowpea grower combine cultural practices with suitable pre and post herbicides like as pendimethalin, quizalofop-ethyl and imazethapyr to get similar return as weed free plot.

Open Access Original Research Article

Toxicological and Histopathological Responses of African Clariid Mud Catfish, Clarias gariepinus (Buchell, 1822) Fingerlings Expose to Detergents (Zip and Omo)

Ivon Ettah, Andem Bassey, Oju Ibor, Joseph Akaninyene, Ndome Christopher

Annual Research & Review in Biology, Page 1-9
DOI: 10.9734/ARRB/2017/33564

The toxicological and histopathological responses of detergents on Clarias gariepinus fingerlings was studied. Twenty-five (25) fingerlings were used for each aquarium exposed to four (4) different concentrations of the two detergents (Zip and Omo) and the control group. The fingerlings were exposed to 0.000, 400, 450, 500 and 550 ppm of the two detergents and the experiment was done in duplicate. A total of 400 fingerlings of Clarias gariepinus for each detergent were used throughout the study. The mean fingerlings weight used for the study was 1.7 ± 0.2 g. The mortality data trend of fingerlings exposed to different concentrations of the detergents increased with increasing concentration and duration of exposure. The 96 hours LC50 value of Zip and Omo on C. gariepinus fingerlings were 5.45 and 5.60 respectively. The low LC50 value for the fingerlings exposed to the detergents denoted a high toxicity of the detergents. Zip detergent was slightly more toxic to the test organism. Due to high toxicity of the detergents, careless discharge of effluents of detergents should be prevented, and the Government should sensitize its citizen on the lethal and sub-lethal effects of detergent to the aquatic eco-system. Also, the discharge of detergent effluents into our environment should be discouraged, in order to maintain a healthy aquatic environment.

Open Access Original Research Article

Physiological Dynamics of Spontaneous Erythrocytes’ Aggregation of Rats at Last Ontogenesis

Zavalishina S. Yu

Annual Research & Review in Biology, Page 1-7
DOI: 10.9734/ARRB/2017/33616

In modern biology we still have the actual demand of further investigation of aging aspects of mammals and human beings. Great attention in this investigation is devoted to different aspects of blood rheological peculiarities and its regular elements, i.e. in aging aspect, in normal state and in some pathology conditions and, also, on the background of many variants of correctional impacts on an organism. The purpose is to establish the age dynamics of microrheological particular properties of aging rats’ red blood cells. The study involved 95 healthy Wistar male rats that included 32 rats of 18 months of age, 29 rats of 24 months and 34 rats of 30 months of age. We used biochemical, hematological and statistical methods. The control group was represented by 27 healthy Wistar male rats. Examined animals on the background of aging were noted to have activity increase of freely radical lipids’ oxidation in the liquid part of blood at the decrease of AOA from 30.70±0.32% at 18 months to 24.40±0.29% at 30 months. Analogical values in the control group were 1.440±0.007 D233/1 ml, 3.460±0.016 umol/l and 34.8±0.010%, correspondingly. Similar picture of POL dynamics of examined animals was also found in erythrocytes: Levels of AHP and MDA in them gradually increased – from 18 months of life to 30 months of life on 27.2% and 26.1%, correspondingly. At the same time experimental rats between 18 and 30 months of life were noted to have increase of erythrocytes’ aggregation activity with the rise of their summary inclusion into aggregates and quantity of aggregates at the lowering of free erythrocytes’ number (228.70±0.31), in comparison with control rats. Found increase of their aggregation is mostly provided by appearing changes in the charge of erythrocyte membranes due to degradation of some negatively charged glycoproteins on them under the influence of increasing with age lipid peroxidation. Aggregation also increases due to inhibition of adenylate cyclase in erythrocytes what leads to the amount decrease of cyclical adenosine phosphate in them and to the stimulation of Ca2+ inflow into them. Development of oxidative damage in plasma globular protein “bridges” between erythrocytes, providing their aggregation, increases erythrocytes’ disaggregation threshold due to the increase of their connection in aggregates. Age increasing erythrocytes’ aggregation in rats negatively influences microcirculation and contributes significantly to marked with aging morbid aggravation due to strengthening a body’s sensitivity to negative impacts of environmental factors which promote the realization of hereditary predisposition to various diseases.