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1.
The predatory mite, Phytoseius plumifer (Canestrini & Fanzago), is one of the most abundant natural enemies and efficient predator of phytophagous mites in Iran. The miticides hexythiazox (Nisorun, EC 10%), fenpyroximate (Ortus, SC 5%), and abamectin (Vertimec, EC 1.8%) were tested in the laboratory for their side effects on P. plumifer. The miticides were applied at the highest field recommended concentration (N) to detached leaves using a Potter Tower to deposit 2 mg spray solution per cm2. Percent predator mortality was evaluated from the protonymph up to the adult stage including the first five days of the oviposition period. Analysis of data showed that the total effect values of hexythiazox were below the lower threshold, and thus it could be considered to be a harmless miticide to P. plumifer. In contrast, the total effects of fenpyroximate and abamectin were found harmful to the predatory mite at the highest field recommended concentrations.  相似文献   
2.
This study was designed to examine the main effects and interactions of time, presence of antibiotics, and type of sperm activators on the fertilization capacity (eyeing rate) of refrigerated semen of rainbow trout, Oncorhynchus mykiss. The semen samples were stored in the presence or absence of 250 IU ml?1 penicillin and 250 μg ml?1 streptomycin sulfate. Freshwater and a saline solution were used as sperm activators. The semen samples were stored at 2–3°C and fertilized after 0, 6, 8, 12, 19, and 25 days of storage. Fertilizing capacities of semen samples stored in the presence of antibiotics (63.8 ± 5.6%) were significantly (p < 0.05) higher than those stored in the absence of antibiotics (46.2 ± 6.7%). Also, the fertilizing capacities of stored semen samples activated using saline solution (70.7 ± 5.7%) had significantly (p < 0.05) higher values than those activated using freshwater (39.3 ± 5.9%). Semen samples stored in the absence of antibiotics completely lost fertilizing capacity within 19 days of storage. After 25 days of storage in the presence of antibiotics, induction of fertilization using freshwater and saline solution resulted in 0% and 79.8 ± 1.7% fertility, respectively.  相似文献   
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The present study investigated the effect of arginine on seminal plasma composition in rainbow trout. Male rainbow trout broodstocks (2500 ± 200 g) were fed five practical diets (each consisting of three triplicates) supplemented with Arginine at 0.50%, 1.50% and 2.00%. The control group were fed without arginine. Broodstock feeding lasted for 90 days, and then fish semen was sampled. Results indicated no significant differences in LDH, ALP, Fe2+ and phosphorous content among the different treatments. The lowest levels of AST and ALT and the highest levels of Ca2+ and Mg2+ ions were observed in the treatment fed with 1.50% arginine, which showed significant differences from other treatments (P < 0.05). Moreover, the amount of Cl?, Na+ and K+ ions was significantly increased in the seminal plasma in fish fed diets containing arginine in comparison with the control. As the amount of arginine was increased, the levels of uric acid became significantly greater in contrast to urea and glucose levels. The highest amounts of cholesterol, fructose and total protein were observed in treatments fed on 2.00%, 0.50% and 1.00% arginine, respectively, showing significant differences from other treatments (P < 0.05). The highest pH value was assayed in the 1.50% arginine treatment. Results indicated that arginine had a potential efficacy on semen quality in rainbow trout broodstocks.  相似文献   
5.
Ovulation rate and litter size are important reproduction traits in sheep and are of high economic value. Reproduction traits typically have low to medium heritabilities and do not exhibit a noticeable response to phenotypic selection. Therefore, inclusion of genetic information of the genes associated with reproductive ability could efficiently enhance the selection response. The most important major genes affecting prolificacy and their genetic diversities in different sheep breeds were reviewed. Different causative mutations with major effects on reproductive traits including ovulation rate and litter size have been found in various sheep breeds around the world. A general overview of the studies on main prolificacy genes showed that some alleles may express different phenotypic effects in different breeds, and thus, further studies on epistatic effects are necessary for more understanding of genetic control of reproductivity in sheep. Regarding the polygenic control of fertility traits, application of new high‐throughput technologies to find new variants is essential for future studies. Moreover, genomewide association studies and genomic best linear unbiased predictions of breeding values are likely to be effective tools for genetic improvement of sheep reproductive performance traits.  相似文献   
6.
Risk screening tools play a crucial role in identifying potential high-risk non-native (NN) fish species. In this study, potentially invasive NN fish species in the Anzali Wetland Complex (AWC), which is located on the south coast of the Caspian Sea (Iran), were identified using the Aquatic Species Invasiveness Screening Kit (AS-ISK). Twenty-nine freshwater fish species were screened of which 13 exist in the AWC and 16 in close proximity to it (“horizon” species). Receiver operating characteristic curve analysis showed that AS-ISK could discriminate reliably between non-invasive and invasive fish species for the AWC. Mean threshold scores were 3.25 for the Basic Risk Assessment (BRA) and 11.75 for the BRA + CCA (BRA + Climate Change Assessment), and these, respectively, classified 89.7% and 86.2% of the species as high risk. The CCA resulted in an increase in the BRA scores for 86.2% of the species, suggesting the need to account in future NN species management for a likely increased invasiveness of those species under future climate conditions. These results suggest that AS-ISK could prove an effective tool for identifying potentially invasive NN freshwater fishes in other wetlands of the Caspian Sea basin.  相似文献   
7.
We compared the dead wood (DW) conditions of Cheshmeh-sar forest and Sardab forest with different management history,including reserve forest and harvested forest. The First forest took 100% inventory from all the available DW. Also dead trees were compared interms of species, shape, location and quality of fracture in both forests.Volumes of dead wood in Cheshmeh-sar and Sardab forests were 207.47and 142.74 m3, respectively. Due to this significant difference, impact onthe management level was determined. In Cheshmeh-sar forest, 42% ofdead trees were standing and 58% were fallen type while in Sardab forest 38.6% were standing and 61.4% fallen. But the difference was not statistically significant between them (p = 0.0587). In terms of quality, dead trees of hard, soft and hollow had the highest frequency, respectively.However, 71.5% of DW was seen as hard dead in Cheshmeh-sar forestwhile hard dead trees in Sardab forests were 54.2%. Soft quality degree ofdead trees which formed in Cheshmeh-sar and Sardab forest were calculated as 26.6% and 43.4% respectively. Also 30% of the dead trees of Sardab forest were eradicated while in Cheshmeh-sar this amount was reduced to 12%. Due to this significant difference ((Р=0/018), it is concluded that the type of management and human interference are affecting the quality of dead trees and makes us to think the human interferences could effect on the ecosystem of touched forests.  相似文献   
8.
This study was conducted to examine the effect of Artemia urmiana nauplii enriched with Pediococcus acidilactici on growth performances, survival rate, and stress resistance of Persian sturgeon (Acipenser persicus). Artemia nauplii were enriched with P. acidilactici at concentration of 1010 CFU/ml for 3 h (T3), 6 h (T6), 9 h (T9), and one nonenriched nauplii treatment (control). Since nauplii enriched for 9 h had the most significant CFU/g, fish were fed with T9 for 11 days and compared with the control. To evaluate the effect of probiotic on fish resistance, Persian sturgeon larvae were subjected to osmotic shocks of 15, 25, or 35 ppt; four pH treatments, pH 5, pH 6, pH 8 or pH = 9; and air for 5, 10, 15, or 20 s on the 11th day. There were no significant differences in final weight, weight gain, CF, SGR, and FCR between T9 and control (P > 0.05). However, the survival rate of larvae fed nauplii enriched for 9 h increased significantly in comparison with the control group (P < 0.05). In addition, significant higher resistance to all stress challenges was observed in the T9 group.  相似文献   
9.
The present study was conducted to investigate the inhibitory effect of alginate coating incorporated with Zataria multiflora Boiss essential oil (ZEO) and lactoperoxidase system (LPOS), individually and in combination, in order to control inoculated Listeria monocytogenes and Escherichia coli O157:H7 in rainbow trout fillets during 16days of storage at 4°C. The antibacterial activity of ZEO was evaluated against Listeria monocytogenes and E. coli O157:H7 through determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC). In vivo study was performed by inoculating four strains of L. monocytogenes as culture cocktail and one strain of E. coli O157:H7 on trout fillets for their survival evaluation during the 16-day storage. Results indicated that ZEO and LPOS, when used in combination in alginate solution, had a stronger effect on the control of mentioned bacteria in trout fillets; however, their individual use could significantly inhibit their growth, when compared to the control. Moreover, it has been implicated that alginate coating, when used with no antimicrobial agent, had a supportive effect on the growth of these pathogenic bacteria. Therefore, the application of alginate coating containing ZEO and LPOS is recommended in foods, especially fish and fish products.  相似文献   
10.
A study was conducted to investigate the effects of dietary citric acid (CA) (0, 1%, 2% and 3%) on the calcium (Ca) and phosphorus (P) contents of muscle, scute and serum of Beluga (Huso huso) juveniles (25.1±1.9 g). After 8 weeks of feeding on the experimental diets, the Ca and P contents of muscle, scute and serum were measured. The results revealed that the addition of 2% and 3% CA significantly increased the Ca and P contents of muscle and serum. Dietary CA had no effect on the Ca content of scute, but the P content of scute was significantly higher compared with additional 1% CA and the control. These results indicate that the addition of CA to the diet of Beluga increased the bioavailability of Ca and P, thereby increasing muscle and scute mineralization.  相似文献   
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