Comparison of food selection and growth performance of koi carp, Cyprinus carpio L., and goldfish, Carassius auratus (L.) in mono- and polyculture rearing in tropical ponds

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.     

Genetic variations in survival of rohu carp (Labeo rohita, Hamilton) after Aeromonas hydrophila infection in challenge tests

A challenge test against Aeromonas hydrophila was conducted using 2062 rohu carp (Labeo rohita) fingerlings obtained from 52 dams and 87 sires (87 full-sib families) of two year-classes (2003 and 2004). Attempts to establish a cohabitant challenge model were not successful. Therefore, fish were challenged by intraperitoneal injection with A. hydrophila in two replicate tanks per year-class, and dead fish were collected hourly. The mortality reached its peak at 16–22 h after challenge and had almost completely stopped after 58 h. The test was terminated after 382 h at which the average survival was 43.9 and 48.9% in the two 2003 year-class tanks, and 77.1 and 35.8% in the two 2004 year-class tanks. Heritability estimates for survival were obtained from sire and dam threshold models (THR) and sire and dam linear repeatability models (LINR). For both types of models the heritability estimates based on data from single tanks were not consistent. For both year-classes, data from one of the two challenged tanks demonstrated significant additive genetic variation in survival during the A. hydrophila infection, whereas the heritability estimates were not significantly different from zero for the other tank. Further, genetic correlation between survivals in the two replicate tanks in each year-class was not significantly different from zero. The differential results from the replicate tanks demonstrate that additional challenge test experiments are needed before firm conclusions can be drawn about the magnitude of additive genetic variation for survival to aeromonasis in rohu carp. A cohabitant challenge model that allows the testing of important defence mechanisms in the skin and mucous membranes of the fish might have been more appropriate. To establish a valid cohabitant challenge model for rohu carp should be given high priority.     

Variability in meteorological droughts as pivotal mechanism for rice production over the middle gangetic plains

The meteorological drought dynamics and its impacts on rice productivity has been evaluated for the Indian Summer Monsoon Rainfall (ISMR) season using the standardized precipitation index (SPI) over the middle Gangetic plains (MGP) of Bihar. The meteorological drought over the ISMR period was found to be a recurring phenomenon coinciding with the rice growing season over Bihar. The rice crop has an intensive water requirement; therefore, it is significantly impacted by the meteorological droughts. In the present study, spatiotemporal characteristics viz. intensity, frequency, and probability of meteorological drought has been assessed along with an investigation for significant trends and detection of regime shift points to identify the impact of drought on rice production. For the purpose, SPI-4 derived from high resolution gridded daily rainfall data (0.25^°?×?0.25^°) from India Meteorological Department (IMD) has been considered to analyse the meteorological drought episodes over agro-climatic zones of Bihar from 1961 to 2019. The regime shifts were determined using the Rodionov test for the drought dynamics and production of rice in Bihar. A moderate to severe drought-prone zone was found over the zone BRZ3B; while zone BRZ2 and BRZ3A showed comparatively a greater number of mild drought events persisting with more than 70% probability of occurrence. An inkling of increasing dependency on groundwater is found, which is in turn governing the rice production regime. The present study shows there is a substantial need for climate resilience and food security policies incorporating the subtle linkage between SPI variability and crop production, especially over rice producing regions of the globe.

     

盐胁迫对扁桃砧木叶片SOD、POD和CAT活性的影响

以温室盆栽的3种扁桃砧木为材料,研究了不同浓度的NaCl、Na2SO4和不同胁迫时间对其叶片活性氧代谢变化的影响.结果表明:NaCl和Na2SO4胁迫下,石头扁桃,桃扁桃和毛桃叶片中POD、CAT活性均随盐浓度的增加而升高,而随着盐胁迫时间的延长其活性有所下降,但都高于对照.SOD活性均随盐浓度的增加先升高后下降,而且后期下降幅度很大.与NaCl胁迫相比,Na2SO4胁迫下这3种砧木叶片中POD、CAT和SOD活性低.从2种盐胁迫下POD、CAT和SOD活性变化规律初步判断这3种砧木的抗盐能力强弱为桃扁桃＞毛桃＞石头扁桃.     

碱性盐胁迫对光果甘草和苦豆子种子萌发的影响研究

研究了不同浓度的碳酸钠对光果甘草和苦豆子种子萌发的影响。结果表明:在不同浓度的碳酸钠盐(Na2CO3)条件下,光果甘草和苦豆子种子的发芽势、发芽率、发芽指数、活力指数和胚根胚芽生长长度均随着Na2CO3浓度的增加而下降。但Na2CO3浓度提升到0.9%时,光果甘草种子还能保持73%的发芽率,而苦豆子种子发芽率只有26%。光果甘草种子发芽的最适Na2CO3浓度为0.9%,临界浓度为1.2%,极限浓度为2.1%。而苦豆子种子发芽的最适Na2CO3浓度为0.6%,临界浓度在0.6%和0.9%之间,极限浓度为1.8%。光果甘草种子的发芽指数和0.9%以上浓度的活力指数都比苦豆子高,而盐害率比苦豆子种子低很多。Na2CO3浓度提高到0.9%时,光果甘草种子的盐害率只有26.71%,而苦豆子种子的为70.28%,由此可以确定,光果甘草种子萌发抵抗Na2CO3盐的能力比苦豆子种子强,能适应含Na2CO3盐量达0.9%以上的恶劣的碱土生态环境。而苦豆子种子萌发抗Na2CO3盐的能力相对较弱,只能适应Na2CO3含量为0.6%的碱性土壤条件。     

Cloning, nucleotide sequence and phylogenetic analyses, and tissue-specific expression of the transferrin gene in Cirrhinus mrigala infected with Aeromonas hydrophila

Transferrin partial complementary DNAs were cloned from the livers of five species in four genera of Indian carps (Indian major carp species: Labeo rohita, Catla catla and Cirrhinus mrigala; medium carp: Puntius sarana; minor carp: Labeo bata) subsequent to polymerase chain reaction amplification with published heterologous primers or self-designed primers derived from conserved regions of transferrin cDNA sequences. The partial transferrin cDNAs of the five species of carps had sizes from 624 to 633 bp (487 bp for L. rohita) and encoded an open reading frame consisting of 206–211 (162 for L. rohita) amino acids. The alignments of carp cDNA sequences showed 85–97% homology and 71–93% homology in deduced amino acid sequences. A phylogenetic tree of amino acid sequences of transferrin cDNAs from carps showed that the relationship among the four genera of Indian carps is well correlated with that derived from classic morphologic analyses. The hypothesized cleavage site and interdomain bridge of transferrin molecule were predicted for the above carp species and interestingly the cleavage site amino acid sequence was found to be conserved among all the carps. To study the tissue-specific expression of the transferrin gene, various tissues (liver, kidney, spleen, brain, muscle, testis, heart, intestine, gill and fin) from apparently healthy (control), moribund and survived C. mrigala experimentally infected with Aeromonas hydrophila infection were analyzed. Transferrin mRNA was detected only in liver RNA and to lesser extent in brain tissue out of the 10 tissues analyzed irrespective of bacterial infection.     

Assessment of Yield and Yield Component of Soybean Genotypes (<Emphasis Type="Italic">Glycine Max</Emphasis> L.) in North of Khuzestan

18 soybean genotypes were examined to investigate the relationships between some principal attributions of morphology with seed yield per soybean, by Random Complete Block Design (RCBD) study. This study was also carried out three replicates to gain reliable results. The results of variance analysis indicated that, there were significance differences among all soybean genotypes. Moreover, the results of correlated analysis revealed that biological yield (0.96), harvest index (0.92), and number of branches (0.92) had the uttermost correlation with seed yield. To data factor analysis, four independent variables justified 99 percent of all data. The first variable, seed yield, justified 96 percent of entire variance. Multiple-Regression Model with method Analytical Regression Model (step-by-step) was utilized to examine soybean seed yield. This model proved that biological yield, thousand seed weight, and harvest index entered into model respectively and justified 98.85 percent of variation of seed yield. Correlated coefficients of considered attributions were equal to 0.96, 0.78, and 0.92, respectively. All of these indexes had significant at 1% in statistical process. Therefore, these traits can be notability used in soybean breeding programs. Also, accordance to cluster analysis, the sample was divided into three groups.     

Effect of micronutrients on B‐N‐Oxalyl l‐α, β‐diamino propionic acid level and its biosynthesis in Lathyrus Sativus

The detoxification of L. sativus grains by spraying of 0.5 ppm cobalt (nitrate) and 20 ppm molybdehum (ammonium molybdate) salts at the maximun flowering stage ‐ a suggestion based on preliminary findings ‐ has been confirmed in this investigation. Regulatory mechanisms of these micronutrients at the enzymatic level were also studied. On the basis of these observations, the involvement of a hitherto unknown biosynthetic pathway of BOAA cannot be ruled out.     

Epidemiology and antibacterial susceptibility patterns of bloodstream infections, 2001-2004: an experience with BACTEC 9240 in Southern Iran

This study was conducted to determine the prevalence of bacteria recovered from bloodstream samples by Bactec 9240 at our hospital wards and to evaluate their antibacterial susceptibility patterns. During January 2001 through December 2004, 9407 referred blood samples in Bactec bottles from admitted patients at three main wards, neonates, pediatrics and adults at Nemazee Hospital, affiliated to Shiraz University of Medical Sciences in Shiraz were processed. Positive cultures were purified and identified according to standard methods. Sensitivity of bacteria to different antibiotics was determined by Kirby-Bauer disk diffusion method. Staphylococcus aureus 132(25%), Escherichia coli 64(12.1%) and Pseudomonas aeruginosa 52(9.8%) were the most pathogenic bacteria which were recovered from the blood samples. Pathogenic microorganisms were isolated from blood samples of 305 (57.8%) at pediatrics, from 181 (34.2%) at adults and from 42 (8%) at neonates wards. The highest antibiotics activities against gram positive isolates observed for vancomycin (98.4%), chloramphenicol (86.4%) and ciprofloxacin (77.4%), while in gram negative bacteria imipenem (96.1%), ciprofloxacin (83%) and amikacin (77.9%), were effective antibiotics. Frequency of isolated bacteria at pediatrics compared to adults and neonates wards were approximately two and seven folds high, respectively which indicates special attention should be paid to pediatrics patients both in prevention and treatment aspects. Vancomycin and imipenim are the effective antibiotics and could cover majority of gram positive and negative bacteria. Therefore, combined administrations of these antibiotics seems mandatory for empirical therapy.     

NaCl胁迫对光果甘草和苦豆子种子萌发的影响

试验研究了不同浓度的氯化钠对光果甘草(Glycyrrhiza glabra L.)和苦豆子(Sophora alopecuroides L.)种子萌发的影响进行了研究。研究结果表明:在不同浓度的NaCl条件下,光果甘草和苦豆子种子的发芽势、发芽率、发芽指数、活力指数和胚根胚芽生长长度均随着盐浓度的增加而下降。但在1.8%浓度时,光果甘草种子仍能保持60%以上的发芽率,而苦豆子种子发芽率只有4.8%。光果甘草种子发芽的最适盐浓度为1.6%,临界浓度为1.9%,极限浓度为2.4%。而苦豆子种子发芽的最适盐浓度为0.9%,临界盐浓度为1.2%,极限盐浓度为1.9%。光果甘草种子的发芽指数、活力指数和盐害指数迅速下降的浓度都比苦豆子高,而盐害率比苦豆子低很多。盐浓度提高到1.9%时,光果甘草种子的盐害率只有40.06%,而苦豆子的为100%,由此可看出,光果甘草的抗盐能力非常强,能适应含NaCl盐量高达1.8%的恶劣的生态环境。而苦豆子的抗盐能力相对较弱,只能适应含盐量为1.2%的土壤条件。对胚根胚芽生长来讲,在低浓度时NaCl盐对胚根胚芽生长的影响较小,浓度升高到1.2%以上,胚根胚芽生长受到严重影响,其中胚根生长受到影响较大。