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1.
To compare the effect of polyculture against conventional monoculture on ornamental carp production, investigations on food selection and growth performance of koi carp (K), Cyprinus carpio L. and goldfish (G), Carassius auratus (L.) were conducted in a 11‐week rearing experiment in two monoculture (100% K and 100% G) and five polyculture (90% K–10% G, 70% K–30% G, 50% K–50% G, 30% K–70% G and 10% K–90% G) conditions in tropical ponds. There were three replicates for each treatment. Environmental conditions and food availability were similar in all the treatments. Ivlev's electivity index showed that both fish species avoided phytoplankton and preferred cladocerans to other zooplankton groups (copepods and rotifers) in monotypic conditions. However, in the polyculture treatments, the positive electivity of goldfish towards cladocerans reduced significantly (P<0.05), while the percentage of copepods, rotifers and phytoplankton in the gut content increased. No significant differences in weight gain, specific growth rate and deformities were recorded at harvest for koi carp between the different treatments (P>0.05). Even the survival rate of koi carp recorded above 90% in all the treatments. However, the goldfish recorded significantly better weight gain, specific growth rate and survival in monoculture (100% G), compared with the polyculture treatments (P<0.05). Goldfish deformities were lowest (P<0.05) in the monoculture treatment (2.42%). The number of marketable fish above a set size limit of 4 g total weight was significantly higher in the two monoculture treatments, compared with the five polyculture treatments (P<0.05). Keeping in view of the dietary similarities of koi carp and goldfish, and the aggressive nature of koi carp in polyculture, it is suggested to refrain from polyculture of goldfish and koi carp until further documentations relating to optimum stocking density and management of polyculture of ornamental carps are available. 相似文献
2.
Efficient water and fertilizer use is of paramount importance both in rain-fed and irrigated rice cultivation systems to tread off between the crop water demand during the dry spell and the fertilizer leaching. This lysimeter study on paddy in a lateritic sandy loam soil of the eastern India, to simulate the water and solute transports using the HYDRUS-1D model, reveals that this model could very well simulate the soil depth-specific variations of water pressure heads and nitrogen (N) concentrations with the efficiency of >86 and 89%, respectively. The change in the level of water ponding depth did not have a significant effect on the time to peak and the temporal variability of N concentration in the bottom soil layer. The lysimeter-scale water balance analysis indicated that the average deep percolation loss and crop water use were 35.01 ± 2.03 and 39.74 ± 1.49% of the total water applied during the crop growth period, respectively. Similarly, the amount of N stored in the plant and lost through soil storage, deep percolation, and other losses (mineralization, denitrification, and gaseous N loss to the atmosphere through plant leaves) were 1.60 ± 0.16, 0.17 ± 0.04, 12.00 ± 0.48, and 86.23 ± 0.41% of the total applied nitrogen, respectively. The simulation results reveal that a constant ponding depth of 3 cm could be maintained in paddy fields to reduce the N leaching loss to 7.5 kgN/ha. 相似文献
3.
Shagufta YASMEEN Nintu MANDAL Anupam DAS Pritam GANGULY Sanjay KUMAR Rajiv RAKSHIT 《土壤圈》2024,34(3):664-675
Soil ecosystem is experiencing stresses due to climate change, and soil inhabitants try to demonstrate their inherent resistance and resilience against those stresses. Application of nanomaterials as agricultural inputs could bring shifts in resistance and resilience patterns of soil microbes and associated enzymes, especially under short-term heat stress. With this background, the impacts of multi-walled carbon nanotube (MWCNT) on the resistance and resilience of soil biological indicators were evaluated. An incubation experiment was conducted with varied MWCNT concentrations (0, 50, 100, 250, and 500 mg kg-1 soil) for 90 d after 24-h heat stress at 48 ±2 ℃ to assess the impacts of MWCNT on soil enzyme activities and microbial populations vis-à-vis their resistance and resilience indices under short-term exposure to heat stress. Enzyme activities were reduced after exposure to heat stress. Resistance indices of enzyme activities were enhanced by MWCNT application on day 1 after heat stress, whereas there was no recovery of enzyme activities after 90-d incubation. Like soil enzyme activities, resistance index values of soil microbial populations followed the similar trend and were improved by MWCNT application. Multi-walled carbon nanotube has the potential to improve resistance indices of soil enzyme activities and microbial populations under heat stress, although they could not recover to their original state during periodical incubation after heat stress. This study helps to understand the relative changes of biological indicators under MWCNT and their ability to withstand heat stress. 相似文献
4.
5.
Hokonohara S Singh UM Jha VC Pradhan A Dev S Mandar RK 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(6):719-722
A buffalo disease, called "Degnala", causing lameness, edema, gangrenous ulceration of hooves or tail, emaciation, recumbency and eventual death, occurs in Eastern Nepal. Clinical examinations manifested lice eggs on hairs, bradycardia, hypothermia, dehydration, exanthema and icterus. Hematologically, increase of band neutrophil, giant platelet, hypoalbuminemia and hyperglobulinemia were characteristics. Microscopically, dark blue tiny particles were seen on red blood cell (RBC) after Giemsa staining. Administration of tetracycline at an early stage of the disease was effective. 相似文献
6.
The status of cell-mediated immunity (CMI) after pesticide exposure was assessed in mice with the help of skin sensitivity and graft versus host reaction tests. It was observed that at 24 hours post-challenge CMI values did not differ significantly from the control, indicating no effect of quinalphos treatment in mice. Goats receiving monocrotophos at a dose rate of 1.0 mg kg-1 body mass for 40 days gave a similar result when CMI was tested with the help of the chemical sensitizer dinitrofluorobenzene (DNFB). Thus the results clearly indicate that the tested organophosphates do not interfere with cellular immunity in the intoxicated animals. 相似文献
7.
Protection of Procambarus clarkii against white spot syndrome virus using recombinant subunit injection vaccine expressed in Pichia pastoris 总被引:1,自引:0,他引:1
ABSTRACT: The potentiality of injection vaccine against white spot syndrome virus (WSSV) in crayfish Procambarus clarkii was investigated. WSSV envelope proteins VP19 and VP28 were expressed in yeast Pichia pastoris GS115. The purified recombinant proteins (2 µg/g of crayfish) were injected intramuscularly, and the same dose injected as a booster shot on fifth day after vaccination. The vaccinated crayfish were divided into two even groups and later challenged orally by WSSV-infected dead crayfish muscle (2 g/individual) on the third and 21st days after the booster shot. The relative percent survival (RPS) in the third-day group was the highest in VP28 (91%), followed by VP19 + VP28 (84%), and VP19 (45%). The RPS for the 21st-day group was the highest in VP28 (78%), followed by VP19 + VP28 (76%), and VP19 (17%). Development of vaccine by using recombinant proteins VP19 and VP28 expressed in yeast is feasible. 相似文献
8.
Kumar Chavlesh Singh Sanjay Kumar Verma Mahendra Kumar Pramanick Kallol Kumar Srivastav Manish Kaur Sukhdeep Kumar Rajeev Ranjan 《Genetic Resources and Crop Evolution》2022,69(2):645-659
Genetic Resources and Crop Evolution - The wild Malus germplasm is considered as a gene reservoir for various biotic and abiotic stresses tolerance/resistance genes, including important novel... 相似文献
9.
The effect of purified aflatoxin B1 on cell-mediated immunity (CMI) in broiler chicks was assessed using doses of 0.3 and 1 mg/kg feed from hatching to 6 weeks of age. Total lymphocyte and T lymphocyte counts and the 2,4-dinitrofluorobenzene skin sensitivity test, graft-versus-host reaction and nitroblue tetrazolium salt reduction tests were used to evaluate CMI. Both doses of aflatoxin B1, including the apparently nontoxic dose of 0.3 mg/kg feed, caused a significant (P less than 0.05) decline in CMI. The functional activity of splenic macrophages was decreased significantly (P less than 0.05) by both doses of the toxin. 相似文献
10.
Genetic analysis and pyramiding of two gall midge resistance genes (Gm-2 and Gm-6t) in rice ( Oryza sativa L.) 总被引:4,自引:0,他引:4
Sanjay Katiyar Satish Verulkar Girish Chandel Yang Zhang Bingchao Huang John Bennett 《Euphytica》2001,122(2):327-334
Asian rice gall midge (Orseolia oryzae) is a major pest across much of south and southeast Asia. This pest is genetically diverse and many gall midge biotypes are
known to exist in each country. During the last three decades, host plant resistance has proved to be the most effective mechanism
of controlling the Asian rice gall midge. Seven genes conditioning resistance to gall midge larvae have been identified in
rice (Oryza sativa) and are being used in cultivar improvement programs. However, some of these genes are rendered ineffective by new gall midge
biotypes. Increased understanding of genetics, inheritance, allelic relationships and linkage is necessary to maximise the
durability of major gene resistance by the pyramiding of these genes. The two genes, Gm-2 and Gm-6(t), are known to confer resistance against a number of biotypes in India and China, respectively. An F3 population derived from a cross between Duokang #1 (donor of Gm-6(t)) and Phalguna (donor of Gm-2) was screened against Chinese gall midge biotype 4 at Guangdong, China, and Indian gall midge biotype 1 at Raipur, India.
At each location, separately,a single gene governed resistance. The parallel segregation of 417 F3progenies for both biotypes at two locations revealed that recombination had occurred between the two genes, establishing
that the two genes are not allelic. However, the two genes Gm-2 and Gm-6(t), were found to be linked with a distance of ∼16.3 cM. A number of lines homozygous at one locus and segregating for the other
locus were identified and selected. These lines were selfed to obtain lines homozygous for the favourable alleles at both
loci (two locus pyramids). This is the first report on use of conventional host-pest interaction method for pyramiding two
closely located Gm-resistance loci of dissimilar effects. The implications of deployment of these pyramids within and across
country borders, with reference to the prevailing gall midge populations are discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献