The effect of probiotic bacteria in culture media using organic fertilizer for population density,biomass production and nutrient quality of Phronima sp. as natural feed

Phronima sp. is a natural feed with high nutrient content, and it can be an alternative substitute for Artemia. The existence of probiotic bacteria in culture media aims to improve water quality through biodegradation, maintain microbial balance and control pathogenic bacteria, so that nutrients in culture media can be utilized by Phronima sp. This study aimed to determine the effect of fermented organic fertilizer by probiotic bacteria in mass culture media on the population density, biomass production and nutrient content of Phronima sp. and to find the best culture media composition for mass culture of Phronima sp. The study was conducted with a completely randomized design with five treatments and three replications. The treatments were as follows: A: 0% chicken manure, 50% rice bran, 50% tofu waste; B: 25% chicken manure, 37.5% rice bran, 37.5% tofu waste; C: 50% chicken manure, 25% rice bran, 25% tofu waste; D: 75% chicken manure, 12.5% rice bran, 12.5% tofu waste and E: 100% chicken manure. The test animals were Phronima sp., and during cultivation, fertilization was carried out every 3 days. Population density and biomass were observed, and proximate analysis, amino acid profile analysis and fatty acid profile analysis were performed. The highest population density was at treatment B, with a peak population of 98 individuals/L that occurred on the 16th day of maintenance culture, and the highest biomass of 0.51 g was at the same treatment. The highest nutrient content was obtained at treatment B, for which the highest protein proximate analysis value was 58.90%, the proportion of the fatty acids comprised of eicosapentaenoic acid was 7.53%, and lysine amino acids were found at 44.16 ppm.     

Establishing larval feeding regimens for the Forktail Blenny Meiacanthus atrodorsalis (Günther, 1877): effects of Artemia strain,time of prey switch and co‐feeding period

This study aimed to establish feeding strategies covering the whole larval period of the forktail blenny, Meiacanthus atrodorsalis, based on the standard hatchery feeds of rotifers and Artemia. Three purposely designed experiments were conducted to determine the appropriate times and techniques to transition larvae from rotifers onto Artemia nauplii of a Great Salt Lake (GSL) strain, and a specialty AF strain, as well as subsequent transition onto enriched metanauplii of GSL Artemia. With a 3‐day co‐feeding period, larvae adapted well to a transition from rotifers to newly hatched GSL Artemia nauplii as early as 5 days posthatching (DPH), and as early as 3 DPH when fed the smaller AF Artemia nauplii. However, prolonging the rotifer‐feeding period up to 11 DPH did not negatively affect survival. Larvae fed Artemia nauplii of the AF strain showed 17–21% higher survival, 24–33% greater standard length and body depth, and 91–200% greater dry weight, after 20 days relative to those fed nauplii of the GSL strain. Meanwhile, enriched Artemia metanauplii of the GSL strain were shown to be an acceptable alternative to AF Artemia nauplii for later larvae, producing similar survival and growth when introduced from 8 DPH. Based on our findings, we recommend feeding M. atrodorsalis larvae rotifers as a first food between 0 and 2 DPH, introducing AF Artemia nauplii from 3 DPH, followed by enriched GSL Artemia metanauplii from 8 DPH onward, with a 3‐day co‐feeding period between each prey change.     

Iodine‐enriched rotifers and Artemia prevent goitre in Senegalese sole (Solea senegalensis) larvae reared in a recirculation system

To study the effect of dietary supplementation of iodine in Solea senegalensis, larvae were randomly distributed in six tanks. Larvae in three tanks were given rotifers and Artemia enriched with iodine in addition to Rich Advance or Super Selco from 2 days after hatch (DAH) until 31 DAH. Larvae in a second set of three tanks were fed control rotifers and Artemia, enriched only with Rich Advance or Super Selco. Samples were collected at 2, 5, 10, 15 and 31 DAH to determine dry weight, total length, myotome height and thyroid status. Larvae fed the iodine‐enriched diet had significantly higher weight at 31 DAH and higher levels of whole body iodine concentration, compared to control larvae. At 31 DAH, larvae from the control treatment showed typical goitrous thyroid follicles. Thyroid cells of larvae from this treatment appeared columnar or afollicular, with the colloid partly or completely depleted, representative of hyperplasia (goitre). The lower growth rate in fish larvae from the control treatment was possibly a consequence of the hyperplasia, and the iodine enrichment prevented Senegalese sole larvae from developing goitre. This study demonstrates the importance of iodine enrichment of live feed for fish reared in a recirculation system.     

Effect of different forms of Artemia biomass as a food source on survival,molting and growth rate of mud crab (Scylla paramamosain)

An experiment was conducted to evaluate the effect of different forms of Artemia biomass as a food source on survival, molting and growth rate of mud crab Scylla paramamosain. Instar 1 crablets with a mean weight of 0.0082 ± 0.0007 g were reared both individually and communally and fed with different diets consisting of fresh shrimp meat (control feed), live Artemia biomass, frozen Artemia biomass and a dried Artemia‐based formulated feed for 40 days. The highest survival was obtained for crablets receiving live Artemia (92.5% and 75.8%) followed by the groups fed with frozen biomass (90.0% and 47.5%), the control feed (72.5% and 24.2%) and the dried Artemia‐based diet (60.0% and 21.7%) for individual and communal cultures, respectively. The intermolt period, the total number of moltings and the growth rate, which were determined on individually reared crabs, showed the same pattern as for survival. The results suggest that crab performance decreased in the following order: live Artemia>frozen Artemia > fresh shrimp meat > dried Artemia‐based formulated feed. Live Artemia biomass proved an ideal feed for nursery of Scylla paramamosain crabs. Frozen Artemia biomass may be an alternative in times of shortage. Our findings illustrate the high potential for local utilization of Artemia biomass in Vietnam for reliable production of mud crab juveniles.     

不同季节终止孵化对巴里坤湖卤虫卵孵化率的影响

本文研究了在不同温度下．巴里坤湖卤虫卵在不同浓度的盐水中浸泡一定时间后终止孵化对孵化率的影响，以及春季采自湖小的虫卵放置一定时间后孵化率的变化情况。结果表明．春季卵采出８ｄ后全部死亡；终止孵化对孵化率有一定的影响．各种因素对孵化率降低的作用及作用大小不同。巴里坤湖成品卤虫卵中的死卵主要产生在春季。     

卤虫卵壳营养成分分析

采用一般营养物质测定方法及液相色谱和气相色谱方法测定了卤虫卵壳营养成分。结果表明:蛋白质58.91％,脂肪5.63％,灰分8.92％;17种氨基酸总量为干物质的57.73％,必需氨基酸含量占氨基酸总量的36.60％;卤虫卵壳含有多种不饱和脂肪酸,其中EPA占8.54％;卤虫卵壳含有多种无机元素,其中钙为13865.23μg/g,铁为9928.17μg/g。卤虫卵壳含有丰富的营养成分,因此可将其开发为营养强化剂或其它动物饲料。     

卤虫的营养

卤虫(Arem ia)是水产经济动物苗种生产中重要的活饵料之一,卤虫营养价值的高低直接影响到苗种生产的成败与效益。笔者拟就卤虫的营养价值研究作一综述,供学者参考。1卤虫粗蛋白及氨基酸的研究卤虫一直被水产界认为是高蛋白的生物饵料。不同发育阶段、不同产地和不同投喂条件下的卤虫,其体内的粗蛋白含量不同。随着卤虫的生长,粗蛋白的含量有逐步增加的趋势。国内文献报道卤虫卵粗蛋白含量为45.44%[1],卤虫去壳卵的粗蛋白含量为43.03%~57%[1-3],以新疆巴里坤盐湖卤虫卵粗蛋白含量最高(57%),卤虫初孵无节幼体粗蛋白含量为54.61%~59.92%[2],养…     

Success of nursing ide (Leuciscus idus, L.) fry related to the period of feeding with live food

The ide Leuciscus idus (Linnaeus 1758) belongs to autochthonous, less frequent and vulnerable fish species in the frame of ichthyofauna of the Czech Republic. It was the reason for testing the possibility of captive breeding and production of fry in a controlled environment. The goal of this paper was to find the optimal transfer time of ide larvae from live food (Artemia salina nauplii) to dry starter feed providing good survival and growth. At the end of the experiment, high values of cumulative survival (in percentages) and individual weight (in milligrammes) were found for ide fry in groups D (90.6%, 178.6 mg; 15 days A. salina + 10 days starter feed), A (89.9%, 169.9 mg; A. salina only) and C (88.6%, 160.4 mg; 10 days A. salina + 15 days starter feed). Significantly lower values of the given parameters were found in group B (57.1%, 92.6 mg; 5 days A. salina + 20 days starter feed), and the lowest ones were in group E (29.8%, 75.6 mg; starter feed only). Mean values of the level of ontogenesis at the end of the experiment in fry of A–E groups were analogous to length and weight growth. Groups D, C and A consisted of juveniles only (J1, J2), and groups B and E consisted of larvae and juveniles (L4, L5, L6, J1, J2). Condition and production parameters [Fulton’s coefficient of condition (FWC), total length (TL), weight (w), specific growth rate (SGR), food conversion ratio (FCR), cumulative survival] and relationships between basic lengths TL, fork length (FL) and standard length (SL) were evaluated.     

First biogeographical survey of Artemia in Tanzania

ABSTRACT

In an Artemia survey conducted along the coast of Tanzania between March and July 2017, 32 salt pans in Tanga, Dar es salaam, Pwani, Lindi, and Mtwara were assessed. Of all visited salt pans, 16 (50%) had either Artemia biomass or cysts or both. Body length ranged from 4.0 mm to 9.5 mm, while the mean and modal lengths were 6.2 mm and 6.0 mm, respectively. Temperature ranged from 27.2°C to 48.7°C, salinity from 20 g L^?1 to >140 g L^?1, pH from 5.8 to 7.8, dissolved oxygen (DO) from 3.1 mg L^?1 to 4.9 mg L^?1, water depth from 10 cm to 75 cm and conductivity from 42.0 ms cm^?1 to 176.6 ms cm^?1. A bisexual population of Artemia franciscana is suggested. Observed cyst states included concave, biconcave, spherical and cracking cysts. This is the first to report on the occurrence of Artemia in Tanzania.     

Energy budget of the Japanese flounder Paralichthys olivaceus (Temminck & Schlegel) larvae fed HUFA-enriched and non-enriched Artemia nauplii

The energy budget of the Japanese flounder Paralichthys olivaceus (Temminck & Schlegel) larvae fed enriched (EA) and non‐enriched (NEA) Artemia nauplii was determined by equating energy intake (EI) with the summation of energy channelled to faeces (F), metabolism (M), excretion (U) and growth (G). Larvae (21 days post hatching, 2.2 mg mean wet wt) were reared in six 80‐L circular tanks with three replicates of 160 larvae per tank and fed EA and NEA for 20 days. EI was calculated from the energy content of consumed nauplii, M from the summation of energy for routine, feeding and active metabolisms, U from ammonia excretion and G from energy gained based on weight gain, while F was the difference between EI and the total of other components. The heat increment of larvae was calculated from the difference of O₂ consumption at post‐prandial and routine conditions. Except for G and F, variables were correlated to the dry body weight (W) of larvae in a power function: Y=aW^b. Coefficients a and b were estimated by regression after a logarithmic transformation of the raw data. Overall, growth and survival rates of the larvae fed EA were higher than those fed NEA. For a larval flounder growing from 2 to 20 mg wet wt, the ingested energy was partitioned as follows: 22.8% to faecal loss, 38.3% to metabolism, 1.5% to urinary loss and 37.4% to growth for the EA group, whereas 35.4% to faecal loss, 28.4% to metabolism, 1.3% to urinary loss and 34.9% to growth for the NEA group. Gross conversion and assimilation efficiencies were higher, but the net conversion efficiency was lower in EA‐fed larvae than NEA‐fed larvae. This study suggests that the higher growth and survival rates of the EA‐fed group compared with the NEA‐fed group were attributed to their higher intake of essential fatty acids, higher metabolism and lower energy loss of faeces.