Optimizing nursery diets for post-metamorphic stage black sea bass: Growth performance,body composition,and feed utilization on open-formulated and commercial starter diets

The objective of this study was to optimize nursery diets for post-metamorphic stage black sea bass by evaluating growth performance, whole-body proximate and fatty acid composition, and utilization of University of North Carolina Wilmington (UNCW)-formulated and commercial diets under laboratory conditions. A feeding trial was conducted to compare two UNCW-formulated diets (D1 and D2) for black sea bass (54% crude protein = CP and 14% crude lipid = CL) and two premium, commercial marine finfish fry diets, Otohime (Reed Mariculture Inc., Campbell, CA, CP = 48% and CL = 14%, CD3) and Gemma Diamond (Skretting, Nutreco, Canada, CP = 57%, CL = 15%, CD4). The UNCW-formulated diet 1 (D1) contained high fish meal (FM, 40% of diet), whereas UNCW-formulated diet 2 (D2) replaced 50% FM protein by high-quality poultry by-product meal (PBM) protein. Post-metamorphic stage black sea bass (~0.60 g, d40ph) were stocked in each of sixteen 75-L tanks at a density of 1 fish per L (75 per tank), with four replicate aquaria per treatment. Fish were fed four times per day (0800, 1100, 1400, and 1600 h) to apparent satiation for 30 days. Final body weight (5.70–5.74), specific growth rate (7.40–7.45%/d), and percent body weight gain (834–848%) of fish fed the UNCW-formulated D1 (FM-based) and D2 (FM + PBM-based) were higher (p < .05) than in fish fed the commercial diets CD3 and CD4 (4.66–5.21 g, 6.80–7.15%/d, and 668–756%, respectively). Feed intake (% body weight/d was significantly lower for fish fed commercial diet (CD4) (3.94) compared with fish fed CD3 (4.20), but feed intake for CD3 was not significantly different compared with the UNCW-formulated diets D1 and D2 (4.10–4.12). Feed conversion ratios (0.76–0.82) were significantly higher for fish fed CD3 (0.82) than for fish fed D1 and CD4 (0.76). Survival was high (99–100%) in all diet treatments. Final whole-body crude protein content (15.2 to 15.9% wet basis), moisture (68.9–69.6%), and ash (4.31–4.77%) showed no significant differences; however, whole-body crude lipid was lower in fish fed CD3 (9.67%) than in fish fed the other diets (9.96–10.22%). Final whole-body fatty acid composition reflected the diet composition. Higher feed consumption and growth of fish fed the UNCW-formulated diets were attributed to a more optimal combination of marine (fish, squid, and krill meals), terrestrial plant (soybean meal) protein sources, and the addition of chemo-attractants, which provided both higher nutritional quality and palatability. The study suggests that the species-specific starter diets may improve growth performance and fingerling quality and may therefore lower production costs under intensive nursery conditions.     

Consumption of shark products: The interface of sustainability,trade (mis)labelling,human health and human rights

Sharks and rays evolved 450 million years ago, during the Late Ordovician Period. However, during the modern Anthropocene, shark populations have declined at considerable rates, and recent global assessments indicate about one in three species is threatened with extinction. A notable reason for this elevated extinction risk is overfishing linked to increased demand for shark fins and other products. Here, we review multiple dimensions of consuming shark products, ranging from stock sustainability, product (mis)labelling and trade, the human health implications of consuming shark products, and illegal, unreported and unregulated fishing and slavery and labour abuses in the fishing industry. We conclude that traceability and increased transparency in seafood supply chains is essential to overcome obstacles to consumption of sustainable, ethical and healthy shark products. We also provide a decision tree outlining steps in consumer choice that would foster such consumption. Our aim is to provide a holistic view on issues concerning the consumption of shark products that will help policymakers, the public, management and law enforcement agencies to advocate for ecologically- and ethically sustainable consumption of shark products and thereby empower the general public to make informed decisions on which shark products they consume.     

孟加拉吉大港地区乡村家庭竹手工业

对孟加拉吉大港地区家庭竹子手工业非农就业的潜力以及对其产生的社会经济效益进行了调查。本地区有40个竹企业,涉及到Hathazcori upazila的4个村庄。80%手工业者的年龄在30~50岁。他们的大多数是未受教育和土地贫瘠的家庭成员。50%的企业是由夫妻或3~5个工人组成的。竹产品主要是满足当地市场的需求。产品是根据季节的变化而决定的。5个产品中,竹书架提供了企业月净收入的41%,平均月净利润约2373.48塔卡,这为促进乡村经济发展起到重要的作用。作者对竹产业发展的状况进行了验证,并提出了建议。     

Anaesthetic efficacy of MS‐222 and AQUI‐S® in advanced size fry of rohu,Labeo rohita, (Hamilton‐Buchanan)

Anaesthetic agents are very useful for reducing the stress caused by handling, sorting, transportation, artificial reproduction, tagging, administration of vaccines and surgical procedures in fish. The efficacy of two anaesthetics: MS‐222 and AQUI‐S^® were tested on rohu, Labeo rohita advanced size fry. The lowest effective doses that produced induction in 3 min or less and recovery times 5 min or less and meet the most criteria of good anaesthetic characteristics were 125 mg L^?1 of MS‐222, and 30 mg L^?1 of AQUI‐S^® in rohu, Labeo rohita advanced size fry. Induction times were significantly decreased with increased in the concentrations of any of the two tested anaesthetic agents. The lowest doses suitable for transportation of rohu advanced size fry observed were: 10–15 mg L^?1 of MS‐222 and 2.5 mg L^?1 AQUI‐S^®. Both anaesthetics showed promising to be used as anaesthetics for handling and transportation in rohu (Labeo rohita) advanced fry.     

Hydathode morphology and role of guttation in excreting sodium at different concentrations of sodium chloride in eddo

Mature leaves of field-grown eddo plants were used for observing hydathode morphology by light and scanning electron microscopies. There were approximately five hydathode pores on the adaxial surface of each leaf tip. A ring structure with two borders around the pore was detected in this study. Further observations revealed a large cavity underneath the pores. The cavity was directly connected to vascular bundles that lacked a bundle sheath, via intercellular spaces among loosely organized parenchyma cells. Many crystal cells were present around the cavity and vascular bundles. To evaluate the role of guttation in sodium excretion under salinity stress, eddo plants were grown in hydroponic solutions containing 0, 1, 4, 8, and 12 mM sodium chloride (NaCl) for 7 d. As the NaCl concentration in the hydroponic solution increased, the sodium contents increased in leaf blades, petioles, and roots but remained unchanged in corms. The sodium concentration in the guttation fluid increased; however, the volume of guttation fluid decreased with increasing NaCl concentrations. Therefore, sodium elimination via guttation decreased with increasing NaCl concentrations. The ratios of the sodium content in guttation fluid to that of leaf blades, leaves, and whole plants decreased with increasing NaCl concentrations. The ratios of potassium to sodium contents in leaves, roots, and guttation fluid also decreased as the NaCl concentration increased. These results indicate that guttation did not eliminate sufficient sodium to play a role in adjusting sodium homeostasis and the ratios of potassium to sodium contents in eddo plants under saline conditions.     

Tree species recognition system based on macroscopic image analysis

An automated wood texture recognition system of 48 tropical wood species is presented. For each wood species, 100 macroscopic texture images are captured from different timber logs where 70 images are used for training while 30 images are used for testing. In this work, a fuzzy pre-classifier is used to complement a set of support vector machines (SVM) to manage the large wood database and classify the wood species efficiently. Given a test image, a set of texture pore features is extracted from the image and used as inputs to a fuzzy pre-classifier which assigns it to one of the four broad categories. Then, another set of texture features is extracted from the image and used with the SVM dedicated to the selected category to further classify the test image to a particular wood species. The advantage of dividing the database into four smaller databases is that when a new wood species is added into the system, only the SVM classifier of one of the four databases needs to be retrained instead of those of the entire database. This shortens the training time and emulates the experts’ reasoning when expanding the wood database. The results show that the proposed model is more robust as the size of wood database is increased.     

Phytoremediation Potential of Vetiver Grass (<Emphasis Type="Italic">Vetiveria zizanioides</Emphasis>) for Treatment of Metal-Contaminated Water

Phytoremediation using vetiver grass (Vetiveria zizanioides) has been regarded as an effective technique for removing contaminants in polluted water. This study was conducted to assess the removal efficiency of heavy metals (Cu, Fe, Mn, Pb, Zn) using vetiver grass (VG) at different root lengths and densities and to determine metals uptake rate by plant parts (root and shoot) between treatments (low and high concentration). Removal efficiency for heavy metals in water by VG is ranked in the order of Fe>Pb>Cu>Mn>Zn. Results showed that VG was effective in removing all the heavy metals, but removals greatly depend on root length, plant density and metal concentration. Longer root length and higher density showed greater removals of heavy metals due to increased surface area for metal absorption by plant roots. Results also demonstrated significant difference of heavy metals uptake in plant parts at different concentrations indicating that root has high tolerance towards elevated concentration of heavy metals. However, the effects were less significant in plant shoot suggesting that metals uptake were generally higher in root than in shoot. The findings have shown potential of VG in phytoremediation for heavy metals removal in water thus providing significant implication for treatment of metal-contaminated water.     

Variation of mineral nutrient contents of modern and heirloom cultivars of cabbage in different regimes of soil fertility

An improvement in the mineral nutrient contents of fruits and vegetables is needed to offset reported declines in concentrations of these elements in fruits and vegetables. The declines have been associated with the high productivity of modern cultivars and to depleted soil fertility. This research addressed differences in mineral nutrient concentrations between modern F1 hybrids and heirloom cultivars of cabbage (Brassica oleraceae var. capitata L.)and among fertilization practices with conventional chemical or organic fertilizers and compost. Crop production was greater with the chemical or organic fertilizers than with the compost. Mineral nutrient composition did not vary between modern or heirloom cultivars or among fertilization regimes but varied among cultivars, suggesting that cultivar selection could lead to production of nutrient-rich cabbage. Neither mass of heads nor days to maturation of crops affected nutrient composition.     

Allelopathic potential and an allelopathic substance in mango leaves

The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I₅₀) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options.