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Maximum Growth (maximum + growth)
Terms modified by Maximum Growth Selected AbstractsComparison of temperate and tropical rainforest tree species: growth responses to temperatureJOURNAL OF BIOGEOGRAPHY, Issue 1 2003S. Cunningham Abstract Aim, To investigate whether the latitudinal distribution of rainforest trees in Australia can be explained by their growth responses to temperature. Methods, The rainforest canopy trees Acmena smithii (Poir.) Merrill & Perry, Alstonia scholaris (L.) R. Br., Castanospermum australe Cunn. & C. Fraser ex Hook., Eucryphia lucida (Labill.) Baill., Heritiera trifoliolata (F. Muell.) Kosterm., Nothofagus cunninghamii (Hook.) Oerst., Sloanea woollsii F. Muell. and Tristaniopsis laurina (Sm.) Wilson & Waterhouse were selected to cover the latitudinal range of rainforests in eastern Australia. Seedlings of these species were grown under a range of day/night temperature regimes (14/6, 19/11, 22/14, 25/17, and 30/22 °C) in controlled-environment cabinets. These seedlings were harvested after 16 weeks to determine differences in growth rate and biomass allocation among species and temperature regimes. Results, The temperate species showed maximum growth at lower temperatures than the tropical species. However, there was considerable overlap in the growth rates of the temperate and tropical rainforest types across the temperature range used. Maximum growth of the tropical rainforest types was associated with changes in biomass allocation whereas the temperate rainforest types showed no significant changes in biomass allocation across the temperature range. Main conclusions, All species showed temperatures for maximum growth that were considerably higher than those previously shown for maximum net photosynthesis. The growth responses to temperature of the rainforest species under these experimental conditions provided limited evidence for their restriction to certain latitudes. These growth responses to temperature showed that the physiological assumptions used in various types of vegetation-climate models may not be true of Australian rainforest trees. [source] Co-culture of Buffalo Preantral Follicles with Different Somatic CellsREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2008HS Ramesh Contents The effect of co-culture of buffalo preantral follicles (PFs) with different somatic cells, i.e, cumulus, granulosa, ovarian mesenchymal and oviductal epithelial cells was studied. Large PFs (250,450 ,m) were isolated by microdissecting the trypsin (1%) digested ovarian cortical slices. Cumulus cells were isolated by repeated pipetting of oocytes, granulosa cells were isolated by aspirating from punctured PFs and ovarian mesenchymal cells were isolated from ovarian cortex by scraping the cortical slices and passing through 20 ,m filter. Preantral follicles were cultured in standard culture medium without somatic cells or co-cultured with cumulus cells, granulosa cells, ovarian mesenchymal cells and oviductal epithelial cells for 80 days. The growth rate (,m/day) of the PFs was monitored by measuring follicular diameter on day 0, 30, 60 and 80 days of culture. The viability of PFs was evaluated by trypan blue staining. The results indicated that PFs co-cultured with cumulus, granulosa and ovarian mesenchymal cells had a better development and survivality compared with control and those co-culture with oviductal epithelial cells. Maximum growth and survivality of PFs were achieved when cultured with cumulus cells. It is concluded that inclusion of somatic cells in PF culture media had beneficial effect on the growth of PFs and cumulus cells supported maximum growth and survivality of PFs in vitro of all somatic cells tested. [source] Interacting effects of dietary lipid level and temperature on growth, body composition and fatty acid profile of rohu, Labeo rohita (Hamilton)AQUACULTURE NUTRITION, Issue 6 2004K. Mishra Abstract Three isonitrogenous (320 g kg,1 crude protein, casein and gelatine) semi-purified diets with 80 (L8), 130 (L13) and 180 (L18) g kg,1 lipid (sunflower oil at increasing levels and cod liver oil fixed at 50 g kg,1) at three digestible energy levels (12 096, 13 986 and 15 876 kJ kg,1 dry weight) and were tested, in triplicate, on rohu fingerlings (3.2 ± 0.08 g) at two different temperatures (21 and 32 °C). Fish were fed to apparent satiation, twice daily, at 09.00 and 15.00 h, 7 days a week for 56 days. Maximum growth was obtained at a lipid level of 80 g kg,1 (L8) at 21 °C (439.37%) and 130 g kg,1 (L13) at 32 °C (481.8%). In general growth rate was higher at 32 °C than at 21 °C at all lipid levels. Tissue monounsaturated fatty acid (MUFA) contents decreased with increasing lipid level at 32 °C, but the reverse occurred at 21 °C. At 21 °C, Polyunsaturated fatty acid (PUFA) level increased significantly (P > 0.05) over initial values, but was affected insignificantly by dietary lipid level. At 32 °C, fish fed diet L13 had more n-3 fatty acid (FA) in liver and muscle than the other two dietary groups while at 21 °C, both liver and muscle FA profiles exhibited significant change (P > 0.05) in n-3 and n-6 FA content which corresponded to variation in percent addition of dietary lipid. However, n-3/n-6 ratio was higher for fish fed diet L13 at 32 °C and diet L8 at 21 °C and may be correlated with fish growth. [source] Nutritional requirements of cobia, Rachycentron canadum (Linnaeus): a reviewAQUACULTURE RESEARCH, Issue 11 2009Thomas W K Fraser Abstract Cobia culture has been rapidly gaining in popularity since the early 1990s; however, the relative success of modified commercial diets in aquaculture has delayed the need for specific research into the nutritional requirements of cobia. Recent work has determined optimum dietary protein and lipid levels in juvenile cobia at 45 and 5,15% dry weight respectively. Maximum growth and feed conversion ratios have been recorded at 27,29 °C in juvenile cobia with an optimum ration level determined at 9% initial body weight per day. There is limited information on amino acid and essential fatty acids (EFA) requirements in cobia. Several studies have explored alternate protein sources in juvenile cobia with relative success observed with meat meal, yeast-based protein and various plant based sources including soybean meal. There is no literature on the vitamin or mineral requirements of cobia or the nutritional requirements of larger fish. Therefore future research should focus on the amino acid, EFA, vitamin and mineral requirements of cobia while the protein, lipid and energy requirements of larger cobia should be addressed. Additional work on feed ingredients, choice and palatability would also aid in maximizing culture production while minimizing costs thereby producing a more sustainable product. [source] Thermal adaptation of Arctic charr: experimental studies of growth in eleven charr populations from Sweden, Norway and BritainFRESHWATER BIOLOGY, Issue 2 2005S. LARSSON Summary 1. Experimental growth data for Arctic charr (Salvelinus alpinus L.), all fed on excess rations, from 11 European watercourses between 54 and 70°N were analysed and fitted to a new general growth model for fish. The model was validated by comparing its predictions with the growth rate of charr in the wild. 2. Growth performance varied among populations, mainly because of variation in the maximum growth potential, whereas the thermal response curves were similar. The estimated lower and upper temperatures for growth varied between ,1.7 to 5.3 and 20.8,23.2 °C, respectively, while maximum growth occurred between 14.4 and 17.2 °C. 3. There was no geographical or climatic trend in growth performance among populations and therefore no indication of thermal adaptation. The growth potential of charr from different populations correlated positively with fish body length at maturity and maximum weight in the wild. Charr from populations including large piscivorous fish had higher growth rates under standardised conditions than those from populations feeding on zoobenthos or zooplankton. Therefore, the adaptive variation in growth potential was related to life-history characteristics and diet, rather than to thermal conditions. [source] Thermal performance of juvenile Atlantic Salmon, Salmo salar L.FUNCTIONAL ECOLOGY, Issue 6 2001B. JONSSON Summary 1,Experimental data for maximum growth and food consumption of Atlantic Salmon (Salmo salar L.) parr from five Norwegian rivers situated between 59 and 70°N were analysed and modelled. The growth and feeding models were also applied to groups of Atlantic Salmon growing and feeding at rates below the maximum. The data were fitted to the Ratkowsky model, originally developed for bacterial growth. 2,The rates of growth and food consumption varied significantly among populations but the variation appeared unrelated to thermal conditions in the river of population origins. No correlation was found between the thermal conditions and limits for growth, thermal growth optima or maximum growth, and hypotheses of population-specific thermal adaptation were not supported. Estimated optimum temperatures for growth were between 16 and 20 °C. 3, Model parameter estimates differed among growth-groups in that maximum growth and the performance breadth decreased from fast to slow growing individuals. The optimum temperature for growth did not change with growth rate. 4, The model for food consumption (expressed in energy terms) peaked at 19,21 °C, which is only slightly higher than the optimal temperature for growth. Growth appeared directly related to food consumption. Consumption was initiated ,2 °C below the lower temperature for growth and terminated ,1·5 °C above the upper critical temperature for growth. Model parameter estimates for consumption differed among growth-groups in a manner similar to the growth models. 5,By combining the growth and consumption models, growth efficiencies were estimated. The maximum efficiencies were high, 42,58%, and higher in rivers offering hostile than benign feeding and growth opportunities. [source] Cobalt requirement of beef cattle , feed intake and growth at different levels of cobalt supplyJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3 2000F. J. Schwarz Summary In a study using a total of 36 German Simmental beef bulls weighing between 236 kg and about 620 kg the question of what constitutes an adequate Co supply was investigated with reference to the performance criteria growth, feed intake, energy intake, nutrient intake and carcass criteria. The bulls received a diet of corn silage ad libitum and 2.5 kg concentrate for a period of 280 days. Ten rations (R) with graduated Co supplements were fed with mean concentrations of 0.07 (R1), 0.09 (R2), 0.11 (R3), 0.15 (R4), 0.18 (R5), 0.26 (R6), 0.33 (R7), 0.42 (R8), 0.59 (R9) and 0.69 (R10) mg Co per kg dry matter (DM) intake. The Co supplement was added as CoSO47H2O. The diets with no or low Co supplementation produced either distinctly lower daily gains of 1045g (R1) and 1130g (R2) or lower daily gains of about 1260 g (R3, R4) than rations R5,R10, where daily gains averaged 1340 g. The mean daily feed intake per animal was also significantly or marginally affected with values of 6.0 kg DM (R1) rising to 7.7 kg DM (R2,R4) versus 7.9 kg DM on average (R5,R10). Calculations using the broken line model and the quadratic model show that the optimal Co supply for maximum growth is 0.12 mg/kg dietary DM and for maximum feed intake, 0.16,0.18 mg Co/kg dietary DM. After taking further biochemical criteria into account (Stangl et al. 2000), a level of 0.20 mg/kg dietary DM is recommended as an adequate Co supply for growing cattle. [source] Comparison of temperate and tropical rainforest tree species: growth responses to temperatureJOURNAL OF BIOGEOGRAPHY, Issue 1 2003S. Cunningham Abstract Aim, To investigate whether the latitudinal distribution of rainforest trees in Australia can be explained by their growth responses to temperature. Methods, The rainforest canopy trees Acmena smithii (Poir.) Merrill & Perry, Alstonia scholaris (L.) R. Br., Castanospermum australe Cunn. & C. Fraser ex Hook., Eucryphia lucida (Labill.) Baill., Heritiera trifoliolata (F. Muell.) Kosterm., Nothofagus cunninghamii (Hook.) Oerst., Sloanea woollsii F. Muell. and Tristaniopsis laurina (Sm.) Wilson & Waterhouse were selected to cover the latitudinal range of rainforests in eastern Australia. Seedlings of these species were grown under a range of day/night temperature regimes (14/6, 19/11, 22/14, 25/17, and 30/22 °C) in controlled-environment cabinets. These seedlings were harvested after 16 weeks to determine differences in growth rate and biomass allocation among species and temperature regimes. Results, The temperate species showed maximum growth at lower temperatures than the tropical species. However, there was considerable overlap in the growth rates of the temperate and tropical rainforest types across the temperature range used. Maximum growth of the tropical rainforest types was associated with changes in biomass allocation whereas the temperate rainforest types showed no significant changes in biomass allocation across the temperature range. Main conclusions, All species showed temperatures for maximum growth that were considerably higher than those previously shown for maximum net photosynthesis. The growth responses to temperature of the rainforest species under these experimental conditions provided limited evidence for their restriction to certain latitudes. These growth responses to temperature showed that the physiological assumptions used in various types of vegetation-climate models may not be true of Australian rainforest trees. [source] Reevaluation of the Dietary Protein Requirement of Japanese Flounder Paralichthys olivaceusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2003Kangwoong Kim An experiment was conducted to determine the dietary protein requirement by different analysis methods and to study the effects of dietary protein levels on growth performance and body composition in Japanese flounder Paralichthys olivaceus fed white fish meal and casein-based diets for 8 wk. After a 1-wk conditioning period, one of six isocaloric diets containing 30, 36, 42, 48, 54, and 60% crude protein (CP) was fed to fish at approximately 4,5% of wet body weight on a dry matter basis to triplicate groups of 15 fish averaging 13.3 ± 0.06 g (mean ± SD). After 8 wk of the feeding trial, weight gain (WG) and feed efficiency (FE) from fish fed 48% CP diet were similar to those from fish fed 42% and 54% CP diets, and were significantly higher than those from fish fed 30, 36 and 60% CP diets (P < 0.05). Fish fed 48 and 54% CP diets had a significant higher specific growth rate (SGR) than did fish fed 30 and 36% CP diets (P 0.05). Protein efficiency ratio (PER) was inversely related to the dietary protein level. No significant differences existed in hematocrit (PCV) and survival rate among the dietary treatments. Broken-line model analysis indicated that the optimum dietary protein level could be 44.0 ± 3.0% for maximum WG in Japanese flounder. Polynomial regression analysis of the dose-response showed that maximum WG occurred at 50.2% (R2= 0.94) based on WG, and the second-order polynomial regression analysis with 95% confidence limits revealed that the range of minimum protein requirement was between 38.9% and 40.3% based on WG. Therefore, these findings suggest that the optimum dietary protein requirement for maximum growth of Japanese flounder is greater than 40%, but less than 44% CP in the fish meal and casein-based diets containing 17.0 kJ/g of energy. [source] Co-culture of Buffalo Preantral Follicles with Different Somatic CellsREPRODUCTION IN DOMESTIC ANIMALS, Issue 5 2008HS Ramesh Contents The effect of co-culture of buffalo preantral follicles (PFs) with different somatic cells, i.e, cumulus, granulosa, ovarian mesenchymal and oviductal epithelial cells was studied. Large PFs (250,450 ,m) were isolated by microdissecting the trypsin (1%) digested ovarian cortical slices. Cumulus cells were isolated by repeated pipetting of oocytes, granulosa cells were isolated by aspirating from punctured PFs and ovarian mesenchymal cells were isolated from ovarian cortex by scraping the cortical slices and passing through 20 ,m filter. Preantral follicles were cultured in standard culture medium without somatic cells or co-cultured with cumulus cells, granulosa cells, ovarian mesenchymal cells and oviductal epithelial cells for 80 days. The growth rate (,m/day) of the PFs was monitored by measuring follicular diameter on day 0, 30, 60 and 80 days of culture. The viability of PFs was evaluated by trypan blue staining. The results indicated that PFs co-cultured with cumulus, granulosa and ovarian mesenchymal cells had a better development and survivality compared with control and those co-culture with oviductal epithelial cells. Maximum growth and survivality of PFs were achieved when cultured with cumulus cells. It is concluded that inclusion of somatic cells in PF culture media had beneficial effect on the growth of PFs and cumulus cells supported maximum growth and survivality of PFs in vitro of all somatic cells tested. [source] Feeding by the Pfiesteria -Like Heterotrophic Dinoflagellate Luciella masanensisTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 3 2007HAE JIN JEONG ABSTRACT. To explore the feeding ecology of the Pfiesteria -like dinoflagellate (PLD) Luciella masanensis (GenBank Accession no. AM050344, previously Lucy), we investigated the feeding behavior and the kinds of prey species that L. masanensis fed on and determined its growth and ingestion rates of L. masanensis when it fed on the dinoflagellate Amphidinium carterae and an unidentified cryptophyte species (equivalent spherical diam., ESD=5.6 ,m), which were the dominant phototrophic species when L. masanensis and similar small heterotrophic dinoflagellates were abundant in Masan Bay, Korea in 2005. Additionally, these parameters were also measured for L. masanensis fed on blood cells of the perch Lateolabrax japonicus and the raphidophyte Heterosigma akashiwo in the laboratory. Luciella masanensis fed on prey cells by using a peduncle after anchoring the prey with tow filament, and was able to feed on diverse prey such as cryptophytes, raphidophytes, diatoms, mixotrophic dinoflagellates, and the blood cells of fish and humans. Among the prey species tested in the present study, perch blood cells were observed to be the optimal prey for L. masanensis. Specific growth rates of L. masanensis feeding on perch blood cells, A. carterae, H. akashiwo, and the cryptophyte, either increased continuously or became saturated with increasing the mean prey concentration. The maximum specific growth rate of L. masanensis feeding on perch blood cells (1.46/day) was much greater than that of A. carterae (0.59/day), the cryptophyte (0.24/day), or H. akashiwo (0.20/day). The maximum ingestion rate of L. masanensis on perch blood cells (2.6 ng C/grazer/day) was also much higher than that of A. carterae (0.32 ng C/grazer/day), the cryptophyte (0.44 ng C/grazer/day), or H. akashiwo (0.16 ng C/grazer/day). The kinds of prey species which L. masanensis is able to feed on were the same as those of Pfiesteria piscicida, but very different from those of another PLD Stoeckeria algicida. However, the maximum growth and ingestion rates of L. masanensis on perch blood cells, A. carterae, H. akashiwo, and the cryptophyte were considerably lower than those of P. piscicida. Therefore, these three dinoflagellates may occupy different ecological niches in marine planktonic communities, even though they have a similar size and shape and the same feeding mechanisms. [source] Effect of dietary protein levels on growth performance and whole body composition of summerling and winterling spotted barbel (Hemibarbus maculates Bleeker)AQUACULTURE NUTRITION, Issue 4 2010J.-M. CHEN Abstract Six test diets with protein levels varying from 250 to 500 g kg,1 were fed to six triplicate groups of summerling (initial weight: 1.56 g) and seven test diets with protein levels varying from 200 to 500 g kg,1 were fed to seven triplicate groups of winterling (initial weight: 9.49 g) for 8 weeks. Weight gain (WG) and feed efficiency (FE) of summerling significantly increased with increasing dietary protein levels from 250 to 350 g kg,1 and slightly declined, but without statistical significance at a dietary protein level of 400 g kg,1, then further significantly decreased with increasing protein levels to 450 and 500 g kg,1; WG of winterling increased significantly with increasing dietary protein levels from 200 to 300 g kg,1 (P < 0.05), and above this level, WG had a tendency to decrease with increasing dietary protein levels. Winterling fed diets with 300 and 400 g kg,1 of dietary protein had significantly higher FE than those fed other diets. WG data analysis by quadratic regressions showed that the optimum dietary protein levels required for the maximum growth of summerling and winterling were 374 and 355 g kg,1 of dry diet respectively. Protein efficiency ratio of both summerling and winterling negatively correlated with levels of dietary protein. The whole body moisture, protein, lipid and ash of summerling after being fed various test diets for 8 weeks were significantly different among treatments (P < 0.05). The whole body moisture and fat of winterling were also significantly affected by dietary protein levels (P < 0.05), while the whole body protein and ash of winterling were not (P > 0.05). [source] A dietary energy level of 14.6 MJ kg,1 and protein-to-energy ratio of 20.2 g MJ,1 results in best growth performance and nutrient accretion in silver barb Puntius gonionotus fingerlingsAQUACULTURE NUTRITION, Issue 6 2009K.N. MOHANTA Abstract Five iso-nitrogenous (300 g protein kg,1 diet) and iso-lipidic (80 g kg,1 diet) semi-purified experimental diets with variable energy levels of 10.5 (D-1), 12.5 (D-2), 14.6 (D-3), 16.7 (D-4) and 18.8 (D-5) MJ kg,1 diets were fed to Puntius gonionotus fingerlings (average weight 1.79 ± 0.02 g) in triplicate groups (15 healthy fishes per replicate) for a period of 90 days to assess the optimum dietary energy level and protein-to-energy ratio (P/E). Fifteen flow-through cement tanks of 100 L capacity with a flow rate of 0.5 L min,1 were used for rearing the fish. Maximum specific growth rate, protein efficiency ratio, protein productive value, RNA : DNA ratio, whole body protein content, digestive enzyme activity and minimum feed conversion ratio was found in fish-fed diet D-3 with 14.6 MJ kg,1 energy level. There were no improvements in all these parameters with the further rise in dietary energy level. Hence, it may be concluded that the optimum dietary gross energy level for maximum growth and nutrient utilization of silver barb is 14.6 MJ kg,1 diet with a resultant P/E ratio of 20.2 g protein MJ,1 diet, when the dietary protein and lipid are maintained at optimum requirement levels of 300 and 80 g kg,1 diet, respectively, for this species. [source] Effect of methionine on intestinal enzymes activities, microflora and humoral immune of juvenile Jian carp (cyprinus carpio var. Jian)AQUACULTURE NUTRITION, Issue 5 2009L. TANG Abstract An 8-week feeding experiment was conducted to determine the effect of dietary methionine supplementation on intestinal microflora and humoral immune of juvenile Jian carp (initial weight of 9.9 ± 0.0 g) reared in indoor flow-through and aerated aquaria. Eight amino acid test diets (350 g kg,1 crude protein, CP), using fish meal, soybean-condensed protein and gelatin as intact protein sources supplemented with crystalline amino acids, were formulated to contain graded levels of methionine (0.6,22.0%) at a constant dietary cystine level of 3 g kg,1. Each diet was randomly assigned to three aquaria. Growth performance and feed utilization were significantly influenced by the dietary methionine levels (P < 0.05). Maximum weight gain, feed intake occurred at 12 g kg,1 dietary methionine (P < 0.05). Methionine supplementation improved hepatopancreas and intestine weight, hepatosomatic and intestine index, intestinal ,-glutamyltransferase and creatine kinase activity, Lactobacillus count, Bacillus count, lysozyme activities, lectin potency, sim-immunoglobulin M content, addiment C3,C4 contents and serum total iron-binding capacity and declined Escherichia coli and Aeromonas counts. Quadratic regression analysis of weight gain against dietary methionine levels indicated that the optimal dietary methionine requirement for maximum growth of juvenile Jian carp is 12 g kg,1 of the dry diet in the presence of 3 g kg,1 cystine. [source] Protein requirement for maintenance and maximum growth of two-banded seabream (Diplodus vulgaris) juvenilesAQUACULTURE NUTRITION, Issue 1 2009R.O.A. OZÓRIO Abstract The effects of various dietary protein levels on growth performance, whole body composition and nutrient utilization were studied in two-banded sea bream (Diplodus vulgaris), a candidate species for aquaculture. Fish (initial weight 6.1 g) were fed to satiety six iso-energetic diets, containing 5%, 12.5%, 25%, 35%, 45% or 55% of crude protein during 72 days. Fish fed 35% and 45% protein attained better growth and feed utilization than the other groups (P < 0.05). Daily growth index and feed conversion ratio were the poorest for fish fed 5% and 12.5% protein (P < 0.001), while the 25% and 55% protein groups had intermediate performance. Lipid retention increased significantly from 13.7% to 30.1% (P < 0.0001) and protein retention decreased from 35.5% to 21.3% (P < 0.01) with increasing protein levels from 12.5% to 45%. Muscle protein, lipid and energy concentrations were not significantly affected by dietary protein level. The estimated protein requirement for maintenance and maximum growth of two-banded seabream growing from 6 to 20 g were 7.5% and 35.7%, respectively. Protein requirements as calculated from body protein gain were 2.3 and 6.5 g of protein intake per kilogram body weight per day. [source] Dietary protein requirement of white sea bream (Diplodus sargus) juvenilesAQUACULTURE NUTRITION, Issue 4 2008R. SÁ Abstract A trial was undertaken to estimate the protein requirement of white sea bream (Diplodus sargus). Five fish meal-based diets were formulated to contain graded levels of protein (from 60 to 490 g kg,1). Each diet was assigned to triplicate groups of 25 fish with a mean individual body weight of 22 g. Fish fed the 60 g kg,1 protein diet lost weight during the trial, while growth improved in the other groups as dietary protein level increased up to 270,370 g kg,1. Feed efficiency improved as dietary protein level increased. Maximum protein efficiency ratio (PER) was observed with the 17% protein diet. N retention (NR) (% N intake) was not different among groups fed diets with 17% protein and above. Ammonia excretion (g kg,1ABW day,1) increased as dietary protein level increased, while no differences in urea excretion were noted. An exponential model was used to adjust specific growth rate and NR (g kg,1 day,1) to dietary protein level. Based on that model, dietary protein required for maximum retention was 330 g kg,1, while for maximum growth it was 270 g kg,1. On a wet weight basis, there were no differences in whole body composition of fish-fed diets with 170 g kg,1 protein and above, except for the protein content, which was lower in group fed the 170 g kg,1 protein diet than the 490 g kg,1 protein diet. Specific activities of hepatic amino acid catabolism enzymes (glutamate dehydrogenase, alanine aminotransferase and aspartate aminotransferase) increased as dietary protein levels increased. There were no differences among groups in fatty acid synthetase and malyc enzyme but 6-phosphate dehydrogenase (G6PDH) was significantly lower in fish fed the 60 g kg,1 protein diet than the 170 and 490 g kg,1 protein diets. [source] Effects of protein-, peptide- and free amino acid-based diets in fish nutritionAQUACULTURE RESEARCH, Issue 5 2010Konrad Dabrowski In the present review, we summarize data related to the utilization of purified diets formulated with the purpose of determining the amino acid requirements in fish independent of the ontogenetic stage and the morphological characteristics of the digestive tract. Expanding present knowledge on the formulation of protein, free amino acid (FAA) and synthetic dipeptide-based diets can provide possible insights that might lead to a better understanding of the mechanism of amino acid utilization in the growth of fish. Differences exist in the utilization of protein, dipeptides or free amino acids for growth between stomach-possessing and stomachless fish with respect to their response to manipulating the proportion of protein and dipeptides in the formulas. Free amino acid-based diets are uniformly inferior. The effects of diet manipulation on indispensable FAA concentrations in the body (muscle) are not simply the result of deamination or the protein synthesis/degradation ratio. The hydroxyproline/proline ratio was confirmed to be of value in quantifying muscle collagen degradation/synthesis and can perhaps be used to quantify the amino acid requirement necessary to maximize the utilization (deposition) of dietary amino acids. In summary, indispensable amino acid requirements for maximum growth in fish can be addressed using diets formulated from protein/peptide/FAA sources. [source] Protein requirements of Atlantic cod Gadus morhua L.AQUACULTURE RESEARCH, Issue 3 2010Jón Árnason Abstract Three feeding trials were conducted to estimate the minimum protein requirements for maximum growth of Atlantic cod (initial size 37,600 g). The diets in each trial were near iso-energetic and contained 47,64% crude protein (CP) in dry matter for small fish while diets for larger fish contained 36,57% CP. There was no significant difference in the final weight of small fish (90,130 g) fed different levels of CP. However, the specific growth rate (SGR) of fish fed 59% and 64% CP (0.9% day,1) was significantly higher than that of fish fed either 47% or 48% CP (0.5,0.7% day,1). The hepato-somatic index (HSI) increased progressively with decreased CP and the feed conversion ratio (FCR) was negatively correlated with CP of the diets. In two trials with larger fish, CP did not significantly affect mean final weight (750,900 g), SGR or FCR. As for the smaller fish, the HSI was negatively correlated with CP and in one of the experiments, the feed intake was also negatively correlated with CP. The feed efficiency tended to be reduced. The results suggest that the protein requirement for maximum growth in Atlantic cod is size dependent: for 40,107 g fish, the minimum CP is 47,52% and for larger fish (400,900 g) it is 36% or lower. [source] Carbohydrate level in the diet of silver barb, Puntius gonionotus (Bleeker) fingerlings: effect on growth, nutrient utilization and whole body compositionAQUACULTURE RESEARCH, Issue 8 2009Kedar Nath Mohanta Abstract Five iso-nitrogenous (300 g crude protein kg,1 diet) semi-purified diets with graded levels of carbohydrate at 220 (D-1), 260 (D-2), 300 (D-3), 340 (D-4) and 380 (D-5) g kg,1 diet were fed ad libitum to Puntius gonionotus fingerlings (average weight 0.59±0.01 g) in triplicate groups (20 fish replicate,1) for a period of 90 days to determine the effect of the dietary carbohydrate level on the growth, nutrient utilization, digestibility, gut enzyme activity and whole-body composition of fish. Fifteen flow-through cement tanks of 100 L capacity with a flow rate of 0.5 L min,1 were used for rearing the fish. The maximum weight gain, specific growth rate, protein efficiency ratio, RNA:DNA ratio, whole-body protein content, protease activity, protein and energy digestibility and minimum feed conversion ratio (FCR) were found in the D-2 group fed with 260 g carbohydrate kg,1 diet. The highest protein and energy retention was also recorded in the same group. However, from the second-order polynomial regression analysis, the maximum growth and nutrient utilization of P. gonionotus fingerlings was 291.3,298.3 g carbohydrate kg,1 diet at a dietary protein level of 300 g kg,1 with a protein/energy (P/E) ratio of 20.58 ,20.75 g protein MJ,1. [source] A robust method for the joint estimation of yield coefficients and kinetic parameters in bioprocess modelsBIOTECHNOLOGY PROGRESS, Issue 3 2009V. Vastemans Abstract Bioprocess model structures that require nonlinear parameter estimation, thus initialization values, are often subject to poor identification performances because of the uncertainty on those initialization values. Under some conditions on the model structure, it is possible to partially circumvent this problem by an appropriate decoupling of the linear part of the model from the nonlinear part of it. This article provides a procedure to be followed when these structural conditions are not satisfied. An original method for decoupling two sets of parameters, namely, kinetic parameters from maximum growth, production, decay rates, and yield coefficients, is presented. It exhibits the advantage of requiring only initialization of the first subset of parameters. In comparison with a classical nonlinear estimation procedure, in which all the parameters are freed, results show enhanced robustness of model identification with regard to parameter initialization errors. This is illustrated by means of three simulation case studies: a fed-batch Human Embryo Kidney cell cultivation process using a macroscopic reaction scheme description, a process of cyclodextrin-glucanotransferase production by Bacillus circulans, and a process of simultaneous starch saccharification and glucose fermentation to lactic acid by Lactobacillus delbrückii, both based on a Luedeking-Piret model structure. Additionally, perspectives of the presented procedure in the context of systematic bioprocess modeling are promising. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Comparison of Growth and Recombinant Protein Expression in Two Different Insect Cell Lines in Attached and Suspension CultureBIOTECHNOLOGY PROGRESS, Issue 4 2001R. A. Taticek Culture conditions required for obtaining maximum recombinant protein concentrations from two cell lines, Spodoptera frugiperda (IPL,-Sf21-AE) and Trichoplusia ni (Tn 5,-1,4), were determined in this work. Conditions studied include mode of culture (suspended vs attached), agitation rates, inoculum sizes, cell concentration at the time of infection, and various serum-free media (SFM). Results were compared with the performance of attached cultures in TnM-FH with 10% fetal bovine serum. Growth rates in the different culture media tested were similar, but the cell numbers achieved (i.e., yield) improved 2 to 2.7-fold in SFM over cultures in TnM-FH. Agitation rates of 150,160 rpm were necessary for maximum growth of suspended Tn 5,-1,4 cells compared to 125,150 rpm for Sf-21 cells. An inoculum size of 5 × 105 cells/mL gave good growth rates and optimum biomass yields for both cell lines. Cultures of both cell lines were infected with viruses encoding for ,-galactosidase or human secreted alkaline phosphatase (seAP). Protein expression in TnM-FH in attached culture showed that Tn 5,-1,4 cells are 2,4.5 times more productive on a per cell basis than Sf-21 cells grown under similar conditions. Production of ,-galactosidase in Sf-21 cells increased 50% in suspension cultures with SFM compared to attached cultures in TnM-FH, but seAP expression was essentially unchanged by culture techniques. The Tn 5,-1,4 cells produced 2.6,4.4 and 2.7,3 times more ,-galactosidase and seAP, respectively, in SFM in suspension compared to Sf-21 cells. EX-CELL 401 and Sf900-II were formulated as optimized SFM for Sf cell lines. However, in Sf-21 cultures EX-CELL 400 performed better than the other two media, as it increased the ,-galactosidase yield up to 25%. Surprisingly, EX-CELL 401 was the best medium for the production of ,-galactosidase by Tn 5,-1,4 cells, resulting in 25% and 69% higher volumetric and specific yields, respectively, compared to EX-CELL 405 which was formulated for this specific cell line. These results show that even when culture media are designed for maximal growth of a specific cell line, other media may provide the best conditions for protein production. [source] | |||||||||||||