Triacylglycerol Content as a Condition Index for Fish, Bivalve, and Crustacean Larvae

1989 ◽  
Vol 46 (11) ◽  
pp. 1868-1873 ◽  
Author(s):  
Angus J. Fraser

The lipid biochemistry of environmentally stressed larval fish, bivalves and crustaceans is presented to illustrate the utility of a larval condition index based on lipid composition. Larvae under environmental stress are often unable to obtain sufficient energy from exogenous sources and, as a result, endogenous energy reserves are catabolised to maintain basal metabolism. The storage lipid triacylglycerol (TAG) is of particular importance in this respect, TAG content consequently correlating with the physiological condition of a larva. However, absolute TAG content cannot be directly correlated with larval condition because of its dependency on larval size. It is proposed that TAG content can be correlated with larval condition when expressed in the form of a TAG-sterol ratio that accounts for the size dependency of TAG content. This proposition is supported by data that illustrate a highly positive correlation between sterol content and dry weight for larval herring and larval American lobster. Examples of TAG-sterol ratios are calculated from a survey of studies relating to the lipid class composition of nutritionally and pollutant stressed larvae of some marine fish and crustaceans.

1995 ◽  
Vol 52 (6) ◽  
pp. 1294-1306 ◽  
Author(s):  
Steve E. Lochmann ◽  
Gary L. Maillet ◽  
Kenneth T. Frank ◽  
Christopher T. Taggart

Atlantic cod (Gadus morhua) larvae were reared under various feeding environments to assess their lipid class composition and survival during development. Lipids were assessed in individual larvae. Triacylglycerol (TAG), phospholipids (PL), and defatted dry weight (DDW) all fell during yolk absorption. TAG increased after initiation of exogenous feeding in different feeding treatments but did not increase in starved larvae. The percentage of individuals greater than 8 d old with high TAG or PL increased with increasing prey concentration. Survivorship was low in all feeding trials, but groups with a larger percentage of individuals in poor condition tended to exhibit a higher risk of death. We suggest a condition index based on a discriminant function using TAG, PL, and DDW. We assessed the condition of field-collected larvae based on this index.


1997 ◽  
Vol 54 (7) ◽  
pp. 1461-1479 ◽  
Author(s):  
S E Lochmann ◽  
C T Taggart ◽  
D A Griffin ◽  
K R Thompson ◽  
G L Maillet

In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a convergent front located at the periphery of a well-mixed gyrelike water mass rotating near the crest of Western Bank (outer Scotian Shelf). Zooplankton wet biomass and plankton abundance (272 and 529 µm size-classes) were also higher in the frontal region relative to the adjacent water masses. We used the frontal feature to test the hypothesis that larvae in frontal regions are in better condition than larvae elsewhere. No significant differences in triacylglycerol content (an index of nutritional condition), Fulton's K condition index, nor in the daylight feeding ratio were found between larvae in the frontal region and those in the adjacent waters. The convergent front acted as a larval collector, but exchange with other water masses eliminated measurable differences in larval condition. Our observations indicate that physically driven retention, not differential mortality (approximated by condition), was responsible for high abundances of cod larvae at this front.


Rangifer ◽  
2005 ◽  
Vol 25 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Sabine Sampels ◽  
Jana Pickova ◽  
Eva Wiklund

Carcass composition in reindeer is affected by feed intake and the age and sex of the animal. Studies have also shown that age, sex, carcass trim fat content and total intramuscular fat content (IMF) influence lipid class composition. The aim of this study was to compare lipid class composition and IMF in relation to carcass weight, conformation and trim fat content, and to investigate how these parameters are affected by age, sex and different feed sources. Five groups of reindeer were studied. Two groups of calves were fed two grain-based pelleted feeds with different lipid compositions for approximately two months before slaughter. One of these groups was fed with conventional pellets, and the other with pellets enriched with linseed cake to increase the amount of n-3 fatty acids in the diet. Three groups of grazing reindeer were also included in the study, consisting of adult males, adult females or calves. Reindeer calves fed pellets had higher slaughter weights, higher trim fat content and better carcass conformation scores compared to the grazing calves. However, there was no significant difference in IMF between pellet-fed and grazing calves. Adult female reindeer had the highest and grazing calves the lowest slaughter weights, trim fat and IMF. There was no difference in lipid class composition in meat from calves fed with the two pelleted feeds, whereas grazing calves had a higher amount of phospholipids. Squalene was identified and quantified as a component of intramuscular lipids in reindeer meat. Effekt av produktionssystem, ålder och kön på slaktkroppskvalitet och några biokemiska egenskaper hos renköttAbstract in Swedish / Sammandrag: Slaktkroppssammansättningen hos renar påverkas av både foderintag, fodersammansättning och djurens ålder och kön. Tidigare har vi visat att renens kön, ålder, mängden intramuskulärt fett (IMF) och putsfett på slaktkroppen påverkar sammansättningen av lipidklasser. Syftet med denna studie var att jämföra lipidklassammansättningen och IMF i relation till slaktkroppens vikt, form och mängden putsfett och att undersöka hur dessa parametrar påverkas av renarnas kön, ålder och olika typer av foder (bete och pellets). Fem grupper renar ingick i studien (totalt 38 djur). Två grupper kalvar utfodrades med två sorters pellets med olika fettsammansättning under två månader före slakt. Den ena gruppen fick normala pellets (CPD) (Renfor Bas) medan den andra gruppen fick pellets som hade en tillsats av linfrökaka (LPD) för att öka mängden n-3 fettsyror i fodret. Dessutom ingick tre grupper betesdjur i studien: vajor, sarvar och kalvar. Utfodring med pellets gav slaktkroppar med bättre klassning, högre slaktvikter och mer putsfett jämfört med slaktkroppar från betande kalvar. Vajorna hade de högsta och betande kalvar de lägsta slaktvikterna, minst putsfett och lägst halt av IMF. Utfodringen med pellets gav ingen signifikant skillnad i IMF mellan betande och utfodrade renkalvar. Vi fann ingen skillnad i lipidklassammansättning mellan de två utfodrade kalvgrupperna, men köttet från de betande kalvarna hade en högre halt av fosfolipider. Vi kunde också identifiera och kvantifiera squalen som en komponent i intramuskulärt fett i renkött.


1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley

The protein, DNA, and RNA content of larvae maintained at 1.0 plankter/mL increased at the rates of 9.3, 9.9, and 9.8% per day, respectively, for the 5 wk after hatching. Protein reserves of larvae held at 0 or 0.2 plankters/mL were depleted by 45 and 35%, respectively, prior to death 12–13 d after hatching. Starved larvae had similar protein concentrations (percent of dry weight), lower RNA concentrations, and higher DNA concentrations than fed larvae. Larvae held at higher plankton densities had higher RNA–DNA ratios and faster growth rates than larvae held at lower plankton densities. The RNA–DNA ratio was significantly correlated (P < 0.01) with the protein growth rate. The RNA–DNA ratio appears to be a useful index of nutritional status in larval Atlantic cod (Gadus morhua) and may be useful for determining if cod larvae were in a period of rapid or slow growth at the time of capture. Key words: RNA–DNA ratio, starvation, protein, nucleic acids, growth, larval fish, Atlantic cod


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