A strain-specific and a sex-associated STS marker for Asian arowana (Scleropages formosus, Osteoglossidae)

A sex‐associated amplified fragment length polymorphism and a strain‐specific random amplified polymorphic DNA marker were identified from Asian arowana (dragonfish; Scleropages formosus Müller & Schlegel) by screening pooled genomic DNA samples from three different strains as well as males and females respectively. Both markers were cloned, sequenced and successfully converted into sequence‐tagged‐site (STS) markers. The strain‐specific STS marker could be applied to differentiate the Indonesian golden strain of Asian arowana from the green and blood‐red strains before the stage when colours become identifiable. Individuals from the green strain could be sexed with an efficiency of 82.7% using the sex‐associated STS marker. Thus, populations with preferred sex ratios can be formed without the need of rearing a large number of fish.     

Larviculture of the Greasy Grouper Epinephelus tauvina F. and the Brown-Marbled Grouper E. fuscoguttatus F. in Singapore

This paper reports the larviculture of two grouper species, the greasy grouper Epinephelus tauvina and the brown-marbled grouper E. fuscoguttatus , and examines the technical feasibility of breeding the fish. Fertilized eggs for larviculture were obtained by induced spawning through multiple hormonal injections of the female brooders, followed by artificial fertilization for the greasy grouper and by natural spawning in netcages for the brown-marbled grouper.
For both species, larviculture was divided into three operational stages, i.e., stage 1 (day 0–12), stage 2 (from day 12 to day 24 for the greasy grouper and to day 30 for the brown-marbled grouper) and stage 3 (day 24 or 30 to metamorphosis). Larvae were transferred to clean tanks after each stage. Total mortality around day 5–8 was common for the greasy grouper. Several modifications, including the feeding with super-small strain rotifers, intensive feeding of rotifers with Nannochloropsis and the use of an oil-skimmer, have been made to improve the situation. Two other major problems in larviculture were the high mortality observed after day 25 in the greasy grouper and the high cannibalism from day 35 onwards for the greasy grouper and from day 30 onwards for the brown-marbled grouper. The shock syndrome exhibited by both species during the periods made culling of the fish impossible.
Based on the spawning and larval characteristics, brown-marbled grouper is considered a better potential species for large scale fry production than the greasy grouper.     

Growth Performance and Proximate and Fatty Acid Compositions of Channel Catfish, Ictalurus punctatus, Fed for Different Duration with a Commercial Diet Supplemented with Various Levels of Menhaden Fish Oil

A 15‐wk study was conducted to evaluate the effect of supplemental menhaden fish oil levels and feeding duration on growth performance and tissue proximate and fatty acid (FA) compositions of juvenile channel catfish, Ictalurus punctatus. Dietary fish oil levels had no effect on final weight gain, feed efficiency, and survival of channel catfish. Tissue lipid contents were directly correlated to dietary lipid levels, while moisture contents were inversely related to dietary lipid levels. Fillet moisture contents progressively decreased, whereas fillet lipid increased with increasing feeding duration. Significant increase in saturated and total n‐3 FAs and decrease in monoenoic and total n‐6 FA in whole body and fillet were observed at each incremental level of dietary fish oil. Percentages of n‐3 and n‐3 highly unsaturated fatty acids in fillet of fish fed the control and 3% fish oil diets decreased with increasing feeding periods, whereas those of fish fed 6 or 9% added fish oil diets remained stable or increased. Ratios of n‐3/n‐6 were statistically comparable throughout the 15‐wk feeding. When expressed in terms of mg/g of fillet, the highest concentration of n‐3 was obtained in fillets of fish fed the 9% added fish oil diet for 15 wk.     

Contamination of palm kernel meal with Aspergillus flavus affects its nutritive value in pelleted feed for tilapia, Oreochromis mossambicus

An assessment of the nutritive value of palm kernel meal (PKM) and aflatoxin‐contaminated PKM (obtained by fermenting PKM with Aspergillus flavus) as a dietary ingredient in pelleted feed for tilapia, Oreochromis mossambicus Peters, was carried out in a 12‐week feeding trial. Seven isonitrogenous (40% crude protein) and isoenergetic (15.1 kJ g^?1) practical diets were formulated and fed close to apparent satiation to triplicate groups of 12 fish (mean initial weight 8.4 ± 0.1 g). The control diet contained 30% fish meal and 10% soybean meal (SBM) proteins. Four other experimental diets containing 20% and 50% of the SBM protein replaced by either PKM or fermented PKM, respectively, were formulated. Two additional diets containing either PKM or fermented PKM supplemented with a commercial aflatoxin adsorber (0.5% Sorbatox^TM) were also formulated. Measured aflatoxin B₁ levels in the fermented PKM‐based diets ranged from 75 to 100 µg kg^?1 diet. The growth performance and feed utilization efficiency of tilapia fed fermented PKM‐based diets were significantly lower than in fish fed the control diet at all inclusion levels (P < 0.05). Despite a small reduction, weight gains of tilapia fed PKM‐based diets were not significantly different compared with fish fed the control diet. The addition of 0.5% Sorbatox did not produce any beneficial or negative effects to the growth of tilapia. Under the dietary conditions of the present experiment, it was concluded that PKM can substitute up to 50% SBM in practical diets for O. mossambicus without much adverse effect to fish growth. However, when PKM was contaminated with A. flavus, its' incorporation into tilapia diets resulted in growth depression as a result of decreased diet digestibility and also possibly because of the presence of anti‐nutrients found in the contaminated PKM.     

Genetic variation in different varieties of Siamese fighting fish using isoelectric focusing of sarcoplasmic proteins

Sarcoplasmic proteins of four colour varieties of Siamese fighting fish, Betta splendens Regan, were analysed by isoelectric focusing (IEF). Genetic polymorphisms were detected in six loci having isoelectric points: 4.92-5.00 (Sp-1), 5.33-5.48 (Sp-2), 5.90 (Sp-3), 6.31-6.35 (Sp-4), 6.58-6.70 (Sp-5) and 6.90 (Sp-6). For the Sp-1, Sp-2, Sp-4 and Sp-5 loci, there were two co-dominant alleles. At Sp-3 and Sp-6, one allele was dominant and the other null. Individuals within each locus were classified into phenotypes A, AB and B. Only homozygotes were found at Sp-2. Allele frequencies were calculated for each locus and tested for accordance with the Hardy-Weinberg equilibrium. Observed values for each phenotype at Sp-1, Sp-3, Sp-4, Sp-5 and Sp-6 agreed well with the expected ones. At Sp-2, genotypic frequencies for each variety deviated markedly (p < 0.01) from the equilibrium. When tested for homogeneity, no significant differences (p 0.95) in gene frequencies were found among the varieties except at Sp-2. Band sharing index (BSI), computed using the BIO-GENE v5.04 program, revealed high intravariety genetic similarities (0.701-0.740) and slightly above-average intervariety values (0.550-0.583). In this study, we estimated the levels of genetic variability in B. splendens, and proposed a genetic model for each polymorphic locus.     

Artificial neural network approach for prediction of ammonia emission from field-applied manure and relative significance assessment of ammonia emission factors

This article presents a systematic method for enhancing the estimation accuracy of ammonia emission from field-applied manure and for assessing the relative significance of ammonia emission factors, using the feedforward-backpropagation artificial neural network (ANN) approach.

The multivariate linear regression (MLR) method well describes the ammonia emission tendency with the emission factor variation. However, ammonia emission from manure slurry is too complex to be captured in a linear regression model. This necessitates a model which can describe complex nonlinear effects between the ammonia emission variables such as soil and manure states, climate and agronomic factors. In the present study, a principle component analysis (PCA) based preprocessing and weight partitioning method (WPM) based postprocessing ANN approach (called the PWA approach) is proposed to account for the complex nonlinear effects.

The ammonia emission is predicted with precision by the 11 emission factors, using the nonlinear ANN approach. The relative importance among the 11 emission factors is identified using the elasticity analysis in the MLR method and using the WPM in the ANN approach. The relative significance obtained quantitatively by the PWA approach in the present study gives an excellent explanation of the most important processes controlling NH₃ emission.     

The mode of seed formation in Allium senescens and two Korean Allium species

The genus Allium includes several important vegetable and ornamental species, and is an economically important crop. The objective of this study was to determine the mode of reproduction in A. senescens L. (2n=6x= 48) and two Allium species collected in Korea. Chromosome numbers of embryo sac mother cells (EMCs) at diplotene of meiosis were 2n = 48 and unreduced in A. senescens. However, normal sexual reproduction was observed at diplotene in both A. senescens var. minor (2n = 2x= 16) and A. nutans L. (2n=4x= 32). Parthenogenetic embryogenesis also occurred in A. senescens at high frequencies among the three Allium species. Antipodal embryos in A. nutans were formed in unpollinated flowers. Normal seeds were not formed in flowers of A. senescens that had been emasculated and kept in sealed conditions. However, normal seeds were formed in the flowers that were pollinated 2 days after anthesis. In conclusion, diplospory, parthenogenesis, and pseudogamy occur in A. senescens.     

The effects of CO2 gas stunning on meat quality of cattle compared with captive bolt stunning

The aim of this study is to assess the effect of CO₂ gas stunning which has not been conducted until now in comparison with captive bolt stunning on the meat quality of cattle. A total of 40 steers were slaughtered following two stunning processes: CO₂ gas stunning (n=20), exposure at 70% CO₂ gas atmosphere for 140 sec; and captive bolt stunning (CBS, n=20). The slaughtered steers were classified into Group A (620–710 kg) and Group B (720–790 kg) by their live weight. CO₂ gas stunning decreases pH value (p<0.05) but increases lightness (p<0.001) and sarcomere length (p<0.001 and p<0.01 for Group A and Group B, respectively) in all live weight groups. Drip loss was increased with CO₂ gas stunning in Group A (620–710 kg of live weight) (p<0.05), whereas WBSF was decreased with CO₂ gas stunning in Group B (720–790 kg of live weight) (p<0.001). Therefore, CO₂ gas stunning negatively affects muscle pH and water-holding capacity in steers but CO₂ gas stunning can improve the tenderness and lightness compared with captive bolt stunning in cattle.     

A Study on Thought of Tea of Hanjae Yi-mok＇s Da-bu

The Da-bu of Hanjae Lee mok （1471-1498） is known as an original masterpiece,which is predominantly documented in Korean tea books.He had always spared no effort to put Confucianists＇ theories and thoughts into practice during his 28-year career.Da-bu tea magnificently reflected his concepts of Confucianism in conjunction with tea-drinking activities.The main contents of Da-bu have included written authors,tea species and production,landscape of tea cultivation,tea plants and leaves,ways of tea-drinking and three-grade tea,tea song of seven cups,5 merits and 6 moralities of tea,benefits of tea-drinking,tea comprehension,etc.According to the views of contents,tea of Hanjae Leemok is the only partner with which we can share life and it can also be beneficial to healthy diets.Not only does it have become part of our daily life,but also be a medicine for our physical and mental disease.He composed the tea song of seven cups,which sufficiently expressed a real practice of the pursued ideal state of Confucianism and Taoism.He also promoted a drinking tea for health enrichment of Confucianists.According to the analytical results of Da-bu,Hanjae＇s tea has recognizably become the personally real practice of Confucianism and state.He had reached the enlightenment for the state of birth and death.After consuming tea,his body and mind immediately changed to the state of joys and wonderland,and also he illustrated that this feeling is not a one-off state,it always comes out whenever drinking.Therefore,based on Hanjae Lee mok,tea drinking is not only the regiment for healthy benefits,but also it is a training method,＂ Dado in My Heart＂,for individuals to train their mind,body,and morality.