Complete Yolk Absorption Research Articles

The ontogeny of haematopoiesis in the marine teleostLeiostomus xanthurusand a comparison of the site of initial haematopoiesis withOpsanus tau

The ontogeny of haematopoiesis in the perciform fish, spotLeiostomus xanthurus, differed from that reported as the norm for fishes, as exemplified by the cypriniform zebrafishDanio rerio, and observed in the batrachoidiform oyster toadfishOpsanus tau. Erythropoiesis in spot was first evident in the head kidney of yolk‐sac larvae 3 days after hatching (DAH). No embryonic intermediate cell mass (ICM) of primitive stem cells or blood islands on the yolk were apparent within embryos. Erythrocytes were first evident in circulation near the completion of yolk absorption,c. 5 DAH, when larvae werec. 2·0 mm notochord length (LN). Erythrocyte abundance increased rapidly with larval development forc. 14 to 16 DAH, then became highly variable following changes in cardiac chamber morphology and volume. Erythrocytic haemoglobin (Hb) was not detected within whole larvae until they were 12 DAH orc. 3·1 mmLN, well after yolk and oil‐globule absorption. The Hb was not quantified until larvae were >47 DAH or >7 mm standard length. The delayed appearance of erythrocytes and Hb in spot was similar to that reported for other marine fishes with small embryos and larvae. In oyster toadfish, a marine teleost that exhibits large embryos and larvae, the ICM and Hb were first evident in two bilateral slips of erythropoietic tissue in the embryos,c. 5 days after fertilization. Soon thereafter, erythrocytes were evident in the heart, and peripheral and vitelline circulation. Initial haematopoiesis in oyster toadfish conformed with that described for zebrafish. While the genes that code for the development of haematopoiesis are conserved among vertebrates, gene expression lacks phylogenetic pattern among fishes and appears to conform more closely with phenotypic expression related to physiological and ecological influences of overall body size and environmental oxygen availability.

Effects of temperature during early life history on embryonic and larval development and growth in haddock

The effect of incubation temperature (2, 4, 6, 8 and 10° C) on haddockMelanogrammus aeglefinusdevelopment and growth during the embryonic period and in subsequent ontogeny in a common post‐hatch thermal environment (6° C) was investigated. Hatching times were inversely proportional to incubation temperature and ranged from 20·3 days at 2° C to 9·1 days at 10° C. Growth rates were directly proportional to incubation temperature during both the embryonic and larval periods. There was a significant decline in growth rates following hatch in all temperature groups. Compared to the endogenously feeding embryos, growth rates in the exogenous period declined by 4·4‐fold at 4° C to 3·9‐fold at 8° C, indicative of the demarcation between the endogenous and exogenous feeding periods. Yolk utilization varied from 17 days at 2° C to 6 days at 10° C and followed a three‐stage sigmoidal pattern with the initial lag period inversely proportional to incubation temperature. Time to 50% yolk depletion varied inversely with temperature but occurred 1–1·5 days post‐hatch at all temperatures. Additionally, the period between 10 and 90% yolk depletion also decreased with increased temperature. Overall developmental rate was sequential with and directly proportional (2·3‐fold increase) to incubation temperature while the time spent in each developmental stage was inversely proportional to temperature. Larger embryos tended to be produced at lower temperatures but this pattern reversed following hatch, as larvae from higher temperature groups grew more rapidly than those from other temperature groups. Larvae from all temperatures achieved a similar length (c.total length 4·5 mm) upon complete yolk absorption. The study demonstrated the significant impact that temperature has upon developmental and growth rates in both endogenous and exogenous feeding periods. It also illustrated that temperature changes during embryogenesis had significant and persistent effects on growth in subsequent ontogeny.

Determination of the rates of fertilization, hatching and larval survival in the Japanese eel, Anguilla japonica, using tissue culture microplates

A method was developed for assessing fertility, hatchability and larval survival in the Japanese eel, Anguilla japonica. Fertilized eggs were stocked in 24-, 48-, and 96-well plates at one egg to one well and maintained at 23 °C without removing dead larvae, changing the water or feeding. Upon hatching, the larvae were often trapped on the surface of the water where they died (surface death). The remaining larvae then showed rather stable survival in the three types of plates beyond the yolk-sac stage, which was completed by day 8 after hatching (DAH). Polyethylene glycol 6000 (PEG 6000) added to the rearing water at 1 or 10 μg/ml markedly suppressed surface death without apparent effect on hatchability, the survival profile or abnormality. These results indicated that the survival rate can be determined easily by stocking the fertilized eggs individually in the wells of microplates with water containing PEG 6000 and by rearing the hatched larvae until the completion of yolk absorption, with little management. By this method, a series of parameters for evaluating the egg quality, rates of fertilization, hatching, survival and abnormality were determined in the artificially maturation-induced Japanese eel: unstable fertility and frequent abnormal development were revealed to be impediments to constant production of larvae at first feeding.

Spawning And Larvae Production Of Common Pandora, Pagellus Erythrinus L.

Spawning of the common pandora (Pagellus erythrinus L.) in captivity was studied at ambient temperature (21.2±1.2°C) during the breeding season in 1998. Broodstock were cultivated in net fishpens and spawned in large fiberglass tanks (10 m diameter) between June and July. Approximately 33.2 million eggs were collected from 30 mature 4-7 year old females, 97% of which were buoyant healthy eggs with diameters ranging 753-801 μm. The eggs were incubat- ed at 19, 21, or 23°C and development and morphological changes were observed until day 50. The best hatching rate (88.9%) was obtained at 19°C. Swim bladder inflation occurred 8-20 days after hatching. The average survival at day 50, at an initial density of 40 larvae/l, was 3.2%. Exogenous feeding began on day 3. Larvae were first fed rotifers, Brachionus plicatilis, and later Artemia nauplii. Larvae completed yolk absorption 78 hours after hatching. A green water envi- ronment was maintained by introducing cultured microalgae (Nannochloropsis oculata and Tetraselmis suecica). Larvae (13.3 mm) transformed into juveniles (18.71 mm) 29-37 days after hatching.

Aroclor 1254 affects growth and survival skills of Atlantic croaker Micropogonias undulatus larvae

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 252:295-301 (2003) - doi:10.3354/meps252295 Aroclor 1254 affects growth and survival skills of Atlantic croaker Micropogonias undulatus larvae Ian D. McCarthy1,2,*, Lee A. Fuiman1, Maria C. Alvarez1 1University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, Texas 78373, USA 2Present address: School of Ocean Sciences, University of Wales-Bangor, Menai Bridge, Askew Street, Anglesey LL59 5AB, Wales *Email: i.mccarthy@bangor.ac.uk ABSTRACT: The aim of this study was to evaluate the effect of environmentally realistic egg loadings of the polychlorinated biphenyl Aroclor 1254 on the subsequent growth and behavioural survival skills of Atlantic croaker Micropogonias undulatus larvae. Adult fish were given a dietary administration of 0 (control) or 0.4 (dosed) mg Aroclor 1254 kg-1 fish d-1 for 2 wk during the final stages of gonadal recrudescence. Fertilised eggs collected from control and dosed adults immediately after spawning contained 0 and 0.66 µg Aroclor 1254 g-1 egg, respectively. Growth rate (increase in total length) of dosed larvae was significantly lower than that of control larvae between 2 and 13 d post-hatching, with dosed larvae showing a 4 d delay in attaining the same size as control larvae. Behavioural assays were conducted to evaluate survival skills of larvae on Days 5 (complete yolk absorption), 9 (complete oil globule absorption), and 13 (larva wholly dependent on exogenous food sources) post-hatching. Survival skills examined were potential foraging rate (routine swimming speed and activity) and the response to a startle (transient vibratory stimulus) stimulus. Routine swimming speed and activity were similar for control and dosed larvae. There was a significant dose x age interaction in the responses of the control and dosed larvae to a vibratory stimulus. The percentage of control larvae responding to the stimulus, and their average and maximum burst speeds, increased with age. In contrast, no such age-related response was found in the dosed larvae. The results indicate that environmentally realistic body burdens of Aroclor 1254 transfer to the eggs and larvae, reducing their growth rates and impairing their startle responses, possibly making the larvae more susceptible to predation. KEY WORDS: Endocrine disrupting chemicals · Polychlorinated biphenyls · Atlantic croaker · Fish larvae · Swimming activity · Predator avoidance · Sublethal effects · Growth Full text in pdf format PreviousExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 252. Online publication date: April 30, 2003 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2003 Inter-Research.

Spawning in captivity and early life history of cultured red porgy, Pagrus pagrus

Spawning in captivity of the red porgy, Pagrus pagrus, was studied at ambient temperature and photoperiod during one breeding season. Spawning lasted 114 days from February 12 to June 5, 1997, within a temperature range of 12.2°C and 18.5°C. The total number of eggs collected during the spawning period was estimated at 77 million of which 14.3% were sinking and 85.7% were buoyant. The percentage of fertilized buoyant eggs was generally high (95–100%). Mean egg diameters ranged from 0.991 to 1.093 mm within a temperature range of 12.2–14.5°C and decreased rapidly with increasing water temperature from 14.5°C to 18.5°C. Larval development, growth, and morphological changes were described from day 0 to day 34. Larvae were reared intensively in 2 m 3 tank under a constant photoperiod (18 h light and 6 h dark), and fed initially on rotifers, followed by Artemia nauplii and weaned onto an artificial diet. A green water technique was applied using Nannochloropsis sp. Larvae completed yolk absorption on day 4 after hatching. Feeding began on day 3. Absorption of the oil globule was completed by day 7. Notochord flexion started on day 20 at about 7.0 mm total length (TL). Transformation from larval to juvenile stage occurred between days 23 and 32 after hatching, at a mean TL of 12.7±1.2 mm. Initial swim bladder inflation occurred between day 5 and day 7 after hatching.

The gill of fish larvae. Is it primarily a respiratory or an ionoregulatory structure?

Based on surface area and chloride cell number, rainbow trout Oncorhynchus mykiss gills appear initially to be more important in terms of ion balance than gas exchange. Chloride cells appear on the gill 3–6 days before hatch at 10°C. This is about 9 days before secondary lamellae, the definitive adult gas exchange structure, begin to form. At hatch, 22% of all chloride cells but only 7% of total surface area are located on the gill. This discrepancy gradually diminishes but even at complete yolk absorption the gill still seems to be about twice as important in terms of ion balance (75% of chloride cells) as gas exchange (37% of total surface area represented by gill filaments and lamellae combined). Surface area measurements and chloride cell counts reported in the literature for larvae of other species show a similar pattern suggesting that this may be a general phenomenon. If true, the implications are profound not only for developmental physiologists but also for those interested in the evolutionary history of gills and their function in adult fish.

The gill of fish larvae. Is it primarily a respiratory or an ionoregulatory structure?

Based on surface area and chloride cell number, rainbow trout Oncorhynchus mykiss gills appear initially to be more important in terms of ion balance than gas exchange. Chloride cells appear on the gill 3–6 days before hatch at 10°C. This is about 9 days before secondary lamellae, the definitive adult gas exchange structure, begin to form. At hatch, 22% of all chloride cells but only 7% of total surface area are located on the gill. This discrepancy gradually diminishes but even at complete yolk absorption the gill still seems to be about twice as important in terms of ion balance (75% of chloride cells) as gas exchange (37% of total surface area represented by gill filaments and lamellae combined). Surface area measurements and chloride cell counts reported in the literature for larvae of other species show a similar pattern suggesting that this may be a general phenomenon. If true, the implications are profound not only for developmental physiologists but also for those interested in the evolutionary history of gills and their function in adult fish.

Energy metabolism in eggs and larvae of the Senegal sole

Oxygen consumption in Solea senegalensis increased during the egg stage reaching values close to 4 nmol O2 ind−1 at hatching. After hatching, larval oxygen consumption continued to increase, reaching a maximum rate of 9.97−1±87 nmol O2 ind−1 h−1 2 days after the opening of the mouth. Body nitrogen content decreased mainly after exhaustion of yolk reserves. Carbon content decreased during the whole endogenous feeding phase, although it decreased twice as quickly after yolk‐sac absorption. The free amino acid (FAA) depletion rate was higher during egg development and the yolk‐sac period. Complete yolk absorption coincided with the consumption of the 90% of initial FAA content in the eggs and the remaining FAA were consumed at a lower rate. Based on stoichiometrical calculations, FAA appears to be the most important energy substrate during the egg stage (86%) in the Senegal sole. During the period from hatching to the mouth opening, contributions of FAA and lipids as metabolic fuels were similar (41 and 47%, respectively). The decrease in larval protein content during starvation indicates that amino acids from body protein are used as energy substrates under food deprivation.

Long-Term Heavy Metal Mixture Toxicity to Embryos and Alevins of Rainbow Trout (Oncorhynchus mykiss)

Possible effects of heavy metal mixture (HMM) on hatching, survival and growth have been tested on the early-life-history stages of rainbow trout. The eggs of rainbow trout were exposed to HMM concentrations of between 12.5% and 200% from fertilisation to near complete yolk absorption, for 70 days. Water hardness and pH were approximately 250 mg/l CaCO3 and 7.5, respectively. The following concentrations of metals in the model mixture tested were taken as 100%: Cu – 0.02, Cr – 0.02, Ni – 0.05, Zn – 0.06, Pb – 0.03, Fe – 0.3, Cd – 0.003, Mn – 0.09 mg/l. The HM concentrations in 100% mixture were close to the mean annual levels of HM found in the discharges from Vilnius City into the Neris River. Hatching was the most sensitive indicator of HMM toxicity. The MATC for the period from fertilisation to viable hatch was estimated to 70.7% HMM. The alevin stage was a less sensitive early life stage to HMM. Significant reduction in viability and growth of alevins was apparent in 200% HMM concentration after 70-da...

Larval development of hoplias cf. Lacerdae (Pisces: Erythrinidae) and delayed initial feeding effects

Larval development of Hoplias cf. lacerdae was studied under laboratory conditions. After hatching, ontogenetic changes were recorded on food-deprived larvae in 12-hour intervals. Mouth opening occurred after 2.5 days and notochord terminated flexure in 6.5 days. Notochord length increased at a constant rate until complete yolk absorption (13,5 days). Larval dry weight and body height diminished gradually up to 21 days after hatching, when all starved larvae died. Every 12 hours after yolk absorption, groups of larvae (n=15), were separeted, and fed with Artemia nauplii for 10 days. The point-of-no-return (when 50% of larvae were unable to feed or to assimilate ingested food after delayed feeding), was not apparent in this species.

伊勢湾産イカナゴのふ化特性と外部栄養への転換

Characteristics of hatching and transition from endogenous to exogenous nutrition of the Japanese sand eel Ammodytes personatus population in Ise Bay, central Japan, were studied in the laboratory. Duration to the peak hatching after fertilization were needed for 15, 13 and 11 days at 10.3°C, 12.0°C and 13.9°C, respectively. In the peak day, 46.1%, 62.3% and 73.2% of the total larvae hatched at the corresponding temperatures. Hatching predominantly occurred within 4 hours after onset of dark period at 17:00. Newly hatched larvae started feeding within 24 hours after hatching. All larvae completed yolk absorption within 13 days, but oil globle remained in 40% of the 30 days-old larvae. The sand eel larvae had a long mixed period of endogenous and exogenous nutrition. Daily growth rate during the first 30 days after hatching was 0.23mm at 10.1°C.

LARVAL DEVELOPMENT OF THE BACK KEELED MULLET LIZA CARINATA

The sex ratio of the fish used in this study, was 1:1.5 females to males. Natural spawning of the keelback mullet, Liza carinata, in captivity was possible and occurred between December and February. The mean fertilized egg diameter of L. carinata was 0.8±.051 mm. Hatching took place after 36 h at 23°C. The mean total length of the just-hatched larvae was 2.0±0.179 mm. Larval developmental stages, growth, and morphological changes of L. carinata were described on the basis of a series of specimens (391 in total) reared from days 1 to 89 after hatching. Details of the larval developmental stages were drawn and photographed, with special reference being taken of morphological transformations. Larvae completed yolk absorption on the sixth day after hatching, and opened their mouths on day 4. Notochord flexion started on the sixteenth day at 5.0 mm total length. Transformation from larval to juvenile stage occurred between days 30 and 51 after hatching. The maximum size of larvae and the minimum size of juveniles which appeared during the transitional period were 19 and 9.9 mm TL, respectively. By day 51, all the larvae had changed into juveniles with a mean TL of 29.3±6.429 mm. The juveniles started to change into young adults with three anal spines by day 88 at a TL of 62 mm.

Modelling the Growth of Salmonid Embryos

A mechanistic model for the growth of salmonid embryos (prior to feeding) is developed with coupled differential equations describing anabolism and catabolism. The equations model changes in embryo and yolk sac masses in which the flux of nutrients to the embryo is controlled by geometric properties of the embryo and yolk. The rate parameter describing this flux is a well defined function of temperature. Water absorption is also a factor in determining mass. The model, describing the size and time-to-arrival at developmental stages, is fit to chinook salmon growth data from fertilization to complete yolk absorption.

Urea and ammonia excretion by embryos and larvae of the African catfish Clarias gariepinus (Burchell 1822)

Yolk-sac larvae and starved larvae of Clarias gariepinus (Burchell 1822), reared at 28°C, were predominantly ammonotelic, but urea excretion contributed about 19±7% to the total nitrogen excretion. Exogenously feeding larvae of C. gariepinus were mainly ammonotelic until 180-205 h post fertilization, but from then on the relative urea excretion stabilized at 44±13%. The contents of total free amino acids (FAA) and ammonia in C. gariepinus peaked around complete yolk absorption. During the first period after hatching 64% of the FAA and 60% of the total ammonia were located in the yolk compartment. The body compartment contained the highest amount of FAA and total ammonia at the end of the yolk-sac period (65 and 77%, respectively). The amount of nitrogen originating from catabolism of amino acids was balanced within 6% by the excreted sum of ammonia and urea. The high degree of ureotelism in C. gariepinus larvae may constitute an adaptive mechanism to a habitat of temporal water shortage.

Description of the early ontogeny of the Atlantic salmon, Salmo salar, with a novel system of interval (state) identification

The sequence of morphological changes through intervals from the time of egg insemination until the time of completed yolk absorption was investigated. The studied time span was divided into more than 100 morphologically discrete states. For this purpose, some quantitative characters, such as number of cells, somite pairs, or caudal fin rays, extent of epiboly, or vascularisation, were selected as key characters, since they seem to provide the most adequate picture of the dynamic developmental process. Descriptions and drawings of 41 states (out of the more than 100) were chosen for the present study to illustrate the embryo and alevin periods. The time it takes to form one somite pair (τS) was used as the unit of relative age and duration of the early ontogenetic states. The morphological description of each state was supplemented by the estimation of the relative age of the embryo or alevin at this state as the value of N/τS, where N is the time elapsed from egg insemination up to any given state at a given constant temperature. It was determined that the developmental rate of Atlantic salmon embryos depends on the incubation temperature according to the equation: Ig Nt = Ig No + (−0.0967 + 0.00207t)t, where NO and Nt are values of τS at temperatures of 0 and t (°C), respectively, taking into account that the values of τS and the duration of the entire embryogenesis vary proportionally within the temperature range tolerated by the species. The methods used here to identify states of embryogenesis and to estimate the relative age of S. salar embryos and alevins might also be applied to other fish species.

Effects of salinity and temperature on eggs and yolk sac larvae of the greenback flounder ( Rhombosolea tapirina Günther, 1862)

The greenback flounder ( Rhombosolea tapirina) is considered to have potential as an aquaculture species in southern Australia. Experiments were conducted to determine the optimal salinity for fertilisation and buoyancy of eggs, the optimal temperature and salinity combination for incubation of eggs, and the optimal temperature for yolk absorption. Experiments were carried out in 25 and 200 ml beakers and 31 containers. Optimal fertilisation rates occurred at salinities of 35–45‰ and eggs were buoyant at salinities above 28‰. The optimal temperature for egg incubation was approximately 12 °C and salinity had no effect if maintained between 15 and 45‰. Yolk absorption appeared to be most efficient at 15 °C as this temperature resulted in the largest larvae at complete yolk absorption and the fastest growth rate. First feeding occurred at the end of yolk absorption but before the oil droplet was absorbed.

Development of the pituitary, thyroid and interrenal glands and applications of endocrinology to the improved rearing of marine fish larvae

A key to success in the culture of marine fish is the mass production of high quality fry, a process largely dependent on successful first feeding and normal development and growth of fish larvae. In this regard it is important to examine the structural and functional development of the endocrine system during early ontogeny of marine fish. To characterize early endocrine development a comparative study was conducted with various marine fish. The age when the pituitary gland differentiated, assessed by immunohistochemical detection of GH and PRL, varied among species, but generally coincided with the time of eye pigmentation, when yolk absorption is very rapid in most marine fish larvae. Thyroid follicles and pancreatic islets first appeared at about the same time, while interrenal cells appeared later. Tissue concentrations of thyroid hormones decreased during embryonic development to nearly undetectable levels at the completion of yolk absorption. During early larval life thyroid hormone levels increased gradually and were significantly elevated during the transformation to the juvenile stage, especially in flatfish. Tissue concentrations of cortisol showed nearly the same developmental pattern, but increased prior to thyroid hormone levels. GH and PRL exhibited different developmental patterns. GH increased continuously during larval growth while PRL exhibited nearly the same pattern as cortisol in Japanese flounder. Based on these findings it is concluded that the endocrine system becomes functional before the completion of yolk absorption in most marine fish, when the switch from a maternal (yolk) to an endogenous larval hormone source occurs. A preliminary experiment on T 4 supplementation indicated that intact protein ingestion by pinocytosis in the rectal epithelium and fat absorption in the intestinal epithelium were enhanced. Potential benefits of exogenous hormone treatment are discussed particularly in relation to digestive functions.

The metabolism of neutral and polar lipids in eleuthero‐embryos and starving larvae of the African catfish Clarias gariepinw

Lipid class analysis was carried out on developing eggs, eleuthero‐embryos (yolk sac larvae) and starving larvae of the freshwater species Clarias gariepinus, using thin layer chromatography. Samples were taken at fixed intervals from a large pool of fertilized eggs obtained through induced reproduction of several parent fish. The total lipid content of fertilized eggs fluctuated around 22% of the dry weight and decreased from 21% at hatching to about 12–5% at yolk absorption. In starving larvae, the amount of total lipid per individual remained relatively constant. Polar lipids [phosphatidylcholine (PC) and phosphatidylethanolamine (PE)] together accounted for 73·6 to 80% of total lipid. PC was by far the most abundant lipid class during the entire experimental period (70–75% of total lipid). PC was catabolized proportionally to total lipid, demonstrating its role as the main energy supplier. All yolk PE was converted to body tissue. The neutral Hpids consisted of triglycerides (TAG), cholesterol and cholesteryl esters (respectively 12·5, 10 and 3% of total lipid in newly fertilized eggs). All TAG were depleted before complete yolk absorption.

A simulation model for the metabolism of yolk sac larvae of the African catfish, Clarias gariepinus (Burchell)

. In fish larvae there is a strong natural selection for high yolk utilization efficiencies and high yolk absorption rates. Larvae with higher absorption and utilization will be larger at the onset of exogenous feeding, leading to higher survival and growth rates in the following stages of development. Modelling can be a powerful tool in clarifying the processes of fish larvae metabolism, providing the model is as explanatory as possible. The present model considers the larvae as a two-compartment system: the yolk sac and the larval body. This system exchanges oxygen, carbon dioxide, water, ammonia and heat with the environment. Yolk is absorbed through the syncytium, digested, and the resulting nutrients are released into the blood circulation. Circulating amino acids and fatty acids are considered to be used first for respiration, and what is left will be used for growth. From the moment that absorbed nutrients do not satisfy the energy needs, embryo tissue starts to be catabolized. Temperature is the only environmental factor which was assumed to affect significantly the metabolic processes. From the comparisons between simulations and experimental data, the simulations would appear to be accurate until complete yolk absorption, losing accuracy afterwards. Simulation outputs suggest that fat is the main energy substrate during yolk absorption, with protein becoming progressively more important, being predominant during starvation. Ideal culture conditions for African catfish yolk sac larvae seem to include: the highest temperature that combines with acceptable mortality rates; selection of broodstck towards obtaining the largest egg size, insofar as viability is not affected; the start of feeding as close as possible to 144 physiological day-degrees.