Effects of Intermediate and Low Salinity Conditions on Growth Rate and Food Conversion of Atlantic Cod (Gadus morhua)

1994 ◽  
Vol 51 (7) ◽  
pp. 1569-1576 ◽  
Author(s):  
Yvan Lambert ◽  
Jean-Denis Dutil ◽  
Jean Munro
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Growth Rates ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Food Conversion ◽  
Coastal Regions ◽  
Low Salinity ◽  
Feeding Regimes ◽  
Food Conversion Efficiency

Growth rates of Atlantic cod (Gadus morhua) were measured under different salinity conditions to test the hypothesis that growth would be best in an isosmotic environment. The results of two experiments (spring and autumn 1991) conducted at three different salinities (7, 14, and 28‰) and two feeding regimes indicate a significant effect of salinity and ration on growth rate. Within each experiment, growth rates were highest for cod maintained in intermediate salinity conditions (14‰). Growth rates in low salinity conditions (7‰) were higher than in seawater (28‰) during the spring, but during the autumn, growth rates of cod held under low salinity conditions and in seawater were similar. Higher growth rates at lower salinities resulted from an increase in food conversion efficiency. They were not associated with an increase in food intake, changes in composition (proteins, lipids, or water), or relative allocation of energy to the tissues (muscle, liver, and gonads) of cod. The results indicate that rearing cod at intermediate salinities, such as would occur in estuaries or coastal regions, could confer an advantage for cod aquaculture.

Relationships Between RNA–DNA Ratio, Prey Density, and Growth Rate in Atlantic Cod (Gadus morhua) Larvae

1979 ◽  
Vol 36 (12) ◽  
pp. 1497-1502 ◽  
Author(s):  
L. J. Buckley
Keyword(s):  
Growth Rate ◽  
Nutritional Status ◽  
Growth Rates ◽  
Prey Density ◽  
Gadus Morhua ◽  
Slow Growth ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Dry Weight ◽  
Dna And Rna

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

scholarly journals Quality of Nephrops as food for Atlantic cod (Gadus morhua L.) with possible implications for fisheries management

2004 ◽  
Vol 61 (6) ◽  
pp. 983-991 ◽  
Author(s):  
Björn Björnsson ◽  
Maria Álvaro Dongala Dombaxe
Keyword(s):  
Growth Rate ◽  
Gadus Morhua ◽  
Specific Growth ◽  
Condition Factor ◽  
Atlantic Cod ◽  
Gonadosomatic Index ◽  
Conversion Ratio ◽  
Food Conversion ◽  
The Mean

Abstract Nephrops was found to be of low quality as food for cod. In a laboratory experiment the mean specific growth rate of 1 kg cod was 0.184 and 0.415% d−1 when fed to satiation on Nephrops and capelin, respectively. This large difference in growth rate resulted not only from less intake of Nephrops (1.19 kg cod−1) than capelin (1.55 kg cod−1) but also because more Nephrops (4.6 kg) than capelin (2.2 kg) were required to produce each kilogramme of cod. Higher food conversion ratio was consistent with lower fat content of Nephrops (1.3%) than capelin (9.2%) but the exoskeleton also reduced the digestion rate of Nephrops. In the groups where Nephrops and capelin of equal mean weight were offered simultaneously, 40% of the diet consisted of Nephrops during the first week and 10% during the final seven weeks of the experiment. At the end of the experiment, condition factor, liver index, and gonadosomatic index were significantly lower for cod fed on Nephrops (0.967, 5.7, 7.1, respectively) than for those fed on capelin (1.086, 15.8, 11.2, respectively). These results suggests that predation by cod on Nephrops might be reduced by regular release of capelin or other similar food in the distributional areas of Nephrops.

Interpopulation differences in growth rates and food conversion efficiencies of young Grand Banks and Gulf of Maine Atlantic cod (Gadus morhua)

2000 ◽  
Vol 57 (11) ◽  
pp. 2223-2229 ◽  
Author(s):  
Craig F Purchase ◽  
Joseph A Brown
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Larval Fish ◽  
Food Conversion ◽  
Life History Variation ◽  
Grand Banks ◽  
In The Wild ◽  
Conversion Efficiencies

Geographically separated Atlantic cod (Gadus morhua) stocks in the northwest Atlantic exhibit life history variation and have been shown to differ genetically. The genetic and environmental contributions to phenotypic differences, however, have not yet been measured. We used common environment experiments to evaluate the importance of temperature on the observed growth variation between Grand Banks (GB) and Gulf of Maine (GOM) cod stocks. Larvae from the GB grew faster than GOM larvae at both 7 and 12°C. Growth rates of juveniles were not different, but GB juveniles had higher food conversion efficiencies than those from the GOM (at both ambient and warm temperatures). The results indicate that faster growth of GOM cod in the wild is not due to a higher genetic capacity for growth rate in GOM than in GB fish. The findings give evidence of genetically based phenotypic variation, which is in agreement with molecular studies on population differentiation in cod, and support the theory of countergradient variation in growth rates of larval fish.

Nucleic acids and enzymes in Atlantic cod (Gadus morhua) differing in condition and growth rate trajectories

1998 ◽  
Vol 55 (4) ◽  
pp. 788-795 ◽  
Author(s):  
Jean-Denis Dutil ◽  
Yvan Lambert ◽  
Helga Guderley ◽  
Pierre U Blier ◽  
Dany Pelletier ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Food Deprivation ◽  
Growth Rates ◽  
Gadus Morhua ◽  
White Muscle ◽  
Atlantic Cod ◽  
Direct Result ◽  
Muscle Lactate ◽  
Lactate Dehydrogenase Activity ◽  
Feeding Regimes

Atlantic cod (Gadus morhua) were exposed to one of four feeding regimes, 16 weeks of food deprivation (U) or satiation feeding (F) or two 8-week periods of food deprivation followed by satiation feeding (UF) or vice versa (FU), to determine whether relationships between nucleic acids or enzymes and growth rates result from a general enhancement of individual condition or are a direct result of enhanced growth rates. Final condition factor (K) differed between treatments, but did not differ between the mixed treatments after either 8 weeks of negative growth (FU) or 8 weeks of positive growth (UF). Intestinal cytochrome c oxidase activity matched the expected short-term growth rates, not only in fed and unfed fish but also in cod exposed to the mixed treatments (FU and UF). White muscle lactate dehydrogenase activity reflected growth rates, but initial levels were not reached within 8 weeks in FU cod. The liver glutamate pyruvate transaminase : DNA ratio reflected differences in K, but not differences in recent growth rates. Myofibrillar proteins decreased in unfed cod, while sarcoplasmic proteins followed changes in K more closely. The RNA:DNA ratio in white muscle did not reflect changes in K or changes in growth rates.

Influence of shearing and level of concentrates offered on the performance of lambs

1990 ◽  
Vol 1990 ◽  
pp. 164-164
Author(s):  
H.J. Black ◽  
D.M.B. Chestnutt
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Food Conversion ◽  
Ad Libitum ◽  
Food Conversion Efficiency ◽  
Voluntary Food Intake

It has been clearly established that shearing ewes during pregnancy increases lamb birthweight (Austin and Young, 1971; Rutter, Laird and Broadbent, 1971; Black and Chestnutt, 1990). Fewer studies have examined the response of fattening lambs to shearing although both Salman and Owen (1981) and Marai, Nowar and Bahgat (1987) noted a significant increase in growth rate. This was accompanied by an increase in voluntary food intake and consequently little change in the food conversion efficiency.The objective of these experiments was to study the influence of shearing on voluntary food intake and growth rate of fattening lambs offered various levels of concentrate feeding plus ad libitum forage.

scholarly journals Effects of photoperiod and exercise on growth, liver size, and age at puberty in farmed Atlantic cod (Gadus morhua L.)

2006 ◽  
Vol 63 (2) ◽  
pp. 355-364 ◽  
Author(s):  
Ø. Karlsen ◽  
B. Norberg ◽  
O.S. Kjesbu ◽  
G.L. Taranger
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Continuous Light ◽  
Gonadal Development ◽  
Natural Light ◽  
Food Conversion ◽  
Liver Size ◽  
Time Required ◽  
Loss Of Appetite ◽  
Food Conversion Efficiency

Abstract Sexual maturation in Atlantic cod (Gadus morhua) results in loss of appetite and weight during spawning, leads to increased production time required to reach desired harvest size, and results in greater mortality and reduced food conversion efficiency. Thus, methods to stop or delay maturation are urgently needed. In the present study, the effect of continuous light (LL) treatment on maturation was tested in combination with different exercise levels in seawater tanks compared with controls under natural light. LL treatment in lightproof tanks arrested gonadal development for at least 8 months. Exercising Atlantic cod by forcing them to swim with 0, 0.5, or 1 body length per second from the summer solstice had no effect on incidence of maturation either under natural light or under LL. Growth was enhanced in the LL groups compared with the NL groups, mainly as a result of the weight loss of the NL groups during spawning.

Growth Rates and Protein Turnover in Atlantic Cod,Gadus morhua

1988 ◽  
Vol 45 (6) ◽  
pp. 951-964 ◽  
Author(s):  
D. F. Houlihan ◽  
S. J. Hall ◽  
C. Gray ◽  
B. S. Noble
Keyword(s):  
Growth Rate ◽  
Weight Loss ◽  
Protein Synthesis ◽  
Growth Rates ◽  
Gadus Morhua ◽  
White Muscle ◽  
Atlantic Cod ◽  
Degradation Rates ◽  
Protein Synthesis And Degradation ◽  
Synthesis And Degradation

Atlantic cod, Gadus morhua, were maintained on different ration levels or starved to produce a variety of growth rates. The in vivo rates of protein synthesis and degradation were determined for the whole fish and various tissues. As ration level, and hence growth rates, increased, both whole-animal protein synthesis and degradation rates increased linearly; growth occurred because of the preponderance of synthesis over degradation. On average, a 300-g cod growing at 1.0%∙d−1synthesised 1.25 g of protein with 0.4 g of this protein remaining as growth. The proportion of total protein synthesis which was retained as growth increased with increasing growth rate; at a maximum growth rate of 2%∙d−1, over 40% of the protein synthesised was retained as growth. The ranking of the tissues in terms of fractional rates of protein synthesis was liver > gills > intestine > spleen > ventricle > stomach > gonads > white muscle. The white muscle, gills, liver, stomach, spleen, and ventricle all showed similar patterns of increased protein synthesis with increased growth rate. The white muscle has the highest efficiency of retention of protein and accounts for 40% of the total protein accretion per day. In starving fish there was a constant level of protein synthesis, irrespective of the rate of weight loss. However, degradation rates increased in the whole animal and in white muscle as the rate of weight loss increased.

Age- and sex-dependent stimulation of growth rate in rats by the adrenal inhibitor trilostane

1987 ◽  
Vol 113 (3) ◽  
pp. 479-484 ◽  
Author(s):  
M. N. Sillence ◽  
R. G. Rodway
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Plasma Corticosterone ◽  
Female Rats ◽  
Male Rats ◽  
Dependent Manner ◽  
Food Conversion ◽  
Male And Female Rats ◽  
Food Conversion Efficiency

ABSTRACT The effects of the adrenal inhibitor trilostane were examined in male and female rats to determine whether growth rate could be improved by lowering circulating plasma corticosterone concentrations. Dose–response studies revealed that in young female rats (125 g) trilostane lowered peak plasma corticosterone levels in a dose-dependent manner. In male rats plasma corticosterone concentrations were reduced only by very high doses of trilostane (200 mg/kg), while lower doses (2–8 mg/kg) actually increased them. Five growth studies were conducted using a total of 90 rats. In female animals, daily injections of trilostane (10 mg/day) caused an age-dependent increase in growth rate ranging from 11% in 127 g rats to 30% in 164 g rats. In three out of four experiments using females, food intake was slightly increased by the drug. Food conversion efficiency was improved consistently by trilostane by up to 18%. Trilostane-treated females had significantly heavier adrenal glands and livers, but lighter kidneys than control rats. When a complete carcass analysis was performed on one experimental group, no significant differences were found. Carcass component weights relative to control values were: body weight (103%), body water (105%), fat-free solids (103%), carcass weight (103%), body length (103%), body fat (95%) and gut content (96%). In male rats (160 g), daily injections of trilostane (10 mg) resulted in a steady and sustained depression of growth rate reflecting a similar fall in food intake, with no change in food conversion efficiency. It is concluded that in older female rats growth rate is constrained by physiological concentrations of glucocorticoids. Younger females are either less sensitive to trilostane or to changes in plasma corticosterone levels. Male rats are less responsive to adrenal suppression by trilostane than are females of a similar age and do not exhibit an anabolic response to this drug. J. Endocr. (1987) 113, 479–484

Effects of Salinity on the Survival and Growth of Pre-Smolt Coho Salmon (Oncorhynchus kisutch)

1971 ◽  
Vol 28 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Robert G. Otto
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Salinity Tolerance ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Management Tool ◽  
Food Conversion ◽  
Survival And Growth ◽  
Food Conversion Efficiency

Salinity tolerance of juvenile coho salmon (Oncorhynchus kisutch) increased markedly during the period from approximately [Formula: see text] months after emergence from the gravel to the onset of the smolt transformation, except for a decline in the fall. In January, salinity tolerance ceased to limit dispersal to the sea. The limiting effects of high salinities on survival were less for larger fish than for smaller individuals and were substantially reduced by a period of exposure to dilute salinities. Growth rate, food intake, and gross food conversion efficiency had the highest values at salinities of 5–10 ppt throughout the pre-smolt period. The results are discussed in relation to the feasibility of using saltwater impoundments as a management tool in increasing coho production.

The plane of nutrition and compensatory growth in pigs

1964 ◽  
Vol 6 (2) ◽  
pp. 227-236 ◽  
Author(s):  
D. W. Robinson
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Food Restriction ◽  
Growth Response ◽  
Compensatory Growth ◽  
Live Weight ◽  
Moderate Degree ◽  
Food Conversion ◽  
Large White ◽  
Food Conversion Efficiency

1. An experiment was carried out with forty individually-fed Large White × Wessex pigs to examine the growth rates of females (gilts) and castrated males after varying periods of time on a restricted plane of nutrition.2. Compensatory growth was made by pigs in all treatments when some restriction in the plane of nutrition had been previously imposed.3. The immediate growth response after the restriction ceased was directly related to the duration of the period of restriction.4. In pigs on a restricted scale of feeding to 80 lb. live-weight, no compensatory growth was observed until a later stage in growth, whereas pigs on a restricted scale for a much longer period to 160 lb. live-weight showed immediate and significant compensatory growth.5. In the periods immediately after the food restriction was lifted, gilts responded more than castrated males on all treatments.6. The effect on the overall growth rate from 45 to 200 lb. live-weight became progressively worse as the period of restriction was prolonged and in no case did the compensatory growth fully compensate for the setback suffered during restriction.7. There were no significant differences in overall food conversion efficiency and it appears that pigs with an even rate of gain and an interrupted growth rate may be equally efficient.8. There were no significant differences in carcass length or dressing-out percentage although a moderate degree of restriction up to 120 lb. live-weight improved grading results, these being related, to non-significant improvements i n food conversion and therefore possibly to a lower carcass fat content.

Sign in / Sign up

Export Citation Format

Share Document