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Selected AbstractsHerbage mass and nutritive value of herbage of extensively managed temperate grasslands along a gradient of shrub encroachmentGRASS & FORAGE SCIENCE, Issue 3 2009S. Kesting Abstract Semi-natural grasslands often serve as important reserves of biodiversity. In Europe extensive grazing by livestock is considered an appropriate management to conserve biodiversity value and to limit shrub encroachment. However, little is known about the influence of shrubs on agronomic values. A gradient analysis of shrub-invaded temperate grasslands (from shrub-free to pioneer forest) in Germany was carried out to test the hypothesis that herbage mass and variables describing nutritive value of herbage decrease with increasing shrub encroachment. The herbage mass of dry matter (DM), variables describing the nutritive value of herbage, composition of the vegetation and mean of Ellenberg's indicator values were analysed with respect to the extent of shrubs. There was a reduction of herbage mass of DM from 3570 to 210 kg ha,1 with increasing shrub encroachment. Metabolizable energy concentration of herbage ranged from 8·9 to 10·2 MJ kg,1 DM and crude protein concentration from 72 to 171 g kg,1 DM, both measures being positively correlated with shrub occurrence. Increasing shrub occurrence was associated with a decrease in water-soluble carbohydrates concentration (from 151 to 31 g kg,1) and a reduction in the indicator ,forage value'. The results indicate a potentially large agronomic value for shrub-encroached temperate grasslands. [source] Agronomic performance and nutritive value of common and alternative grass and legume species in the Peruvian highlandsGRASS & FORAGE SCIENCE, Issue 2 2009K. Bartl Abstract The agronomic performance and nutritive value of twelve annual and perennial grasses and legumes were analysed in order to define alternatives to local forages for dry-season feeding of ruminants in the Peruvian Andes. There were twelve species and two fertilizer treatments (no fertilizer and a N;P;K fertilizer mainly applied at sowing) in an experiment with a randomized complete block design with three replicates at each of two sites. Plant height, soil cover by forage and weed species, frost damage, dry matter (DM) yield and nutritive value of herbage were evaluated in 2005 and 2006. Among the annual species, Hordeum vulgare L. cv. UNA 80 and ×Triticosecale Wittm. had the highest DM yields when fertilized (8226 and 6934 kg ha,1 respectively). Without fertilizer the alternative cultivars had similar DM yields to that of the local forages. Cultivars of Avena sativa L. had lower concentrations of neutral-detergent fibre (NDF) (557 g kg,1 DM) and higher concentrations of predicted net energy for lactation (5·86 MJ kg,1 DM) than the other annual grass species (625 g kg,1 DM and 5·01 MJ kg,1 DM respectively), while the legumes were superior in concentrations of crude protein (277 g kg,1 DM) and NDF (362 g kg,1 DM). Considering the low agronomic performance of the perennial forages, a mixture of fertilized annual grasses and legumes appears the most appropriate approach to meeting the demand for forage of high nutritive value in the Peruvian highlands. [source] Changes in the physiology and feed quality of cocksfoot (Dactylis glomerata L.) during regrowthGRASS & FORAGE SCIENCE, Issue 3 2002R. P. Rawnsley Abstract A glasshouse study was undertaken to determine the physiological and morphological changes in cocksfoot (Dactylis glomerata L.) during regrowth after defoliation. Individual plants were arranged in a mini-sward in a randomized complete block design. Treatments involved harvesting each time one new leaf had expanded (one-leaf stage), up to the six-leaf stage, with the plants separated into leaf, stubble (tiller bases) and roots. Stubble and root water-soluble carbohydrate (WSC), stubble and leaf dry matter (DM), tiller number per plant and leaf quality (crude protein (CP), estimated metabolizable energy (ME) and mineral content) were measured to develop optimal defoliation management of cocksfoot-based pastures. WSC concentration in stubble and roots was highest at the five- and six-leaf stages. Mean WSC concentration (g kg,1 DM) was greater in stubble than roots (32·7 ± 5·9 vs. 9·4 ± 1·5 respectively). There was a strong positive linear relationship between plant WSC concentration and leaf DM, root DM and tillers per plant after defoliation (Adj R2 = 0·72, 0·88 and 0·95 respectively). Root DM plant,1 and tiller DM tiller,1 decreased immediately following defoliation and remained low until the three-leaf stage, then increased from the four-leaf stage. Tillers per plant remained stable until the four-leaf stage, after which they increased (from 9·9 ± 0·5 to 15·7 ± 1·0 tillers plant,1). Estimated metabolizable energy concentration (MJ kg,1 DM) was significantly lower at the six-leaf stage (11·01 ± 0·06) than at any previous leaf regrowth stage, whereas CP concentration (g kg,1 DM) decreased with regrowth to the six-leaf stage. Both the levels of ME and CP concentrations were indicative of a high quality forage throughout regrowth (11·37 ± 0·04 and 279 ± 8·0 for ME and CP respectively). Results from this study give a basis for determining appropriate criteria for grazing cocksfoot-based pastures. The optimal defoliation interval for cocksfoot appears to be between the four- and five-leaf stages of regrowth. Delaying defoliation to the four-leaf stage allows time for replenishment of WSC reserves, resumption of root growth and an increase in tillering, and is before herbage is lost and quality falls due to onset of leaf senescence. [source] Application of possibility theory in the life-cycle inventory assessment of biofuelsINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2002Raymond R. Tan Abstract Data uncertainty issues have constrained the widespread acceptance of life-cycle analysis (LCA) and related methods. This is particularly important in the LCA of fuels due to the wide range of available feedstocks and processing options. Despite recent attempts at standardization, there remain persistent doubts about the general validity of LCA results, often due to uncertainties about data quality. This paper demonstrates the application of possibility theory as a tool for handling life-cycle inventory data imprecision for the case of the net energy balance of coconut methyl ester (CME) as a biodiesel transport fuel. Results derived using a possibililistic computation are contrasted with those arrived at by probabilistic (Monte Carlo) simulation. The two approaches yield comparable results but possibilistic modelling offers significant advantages with respect to computational efficiency. The net energy balance of CME is estimated to be approximately 36 MJ kg,1, significantly higher than the 28 MJ kg,1 net energy typical of rapeseed oil methyl ester (RME) relevant to the U.K. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effects of dietary l -carnitine supplements on growth and body composition in beluga sturgeon (Huso huso) juvenilesJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2008M. Mohseni Summary The effects of dietary l -carnitine on growth performance, whole body composition and feed utilization were studied in beluga, Huso huso. Fish were randomly allocated in 15 tanks (30 fish per tank) and triplicate groups were fed to satiety during 84 days one of five isonitrogenous (41% CP) and isoenergetic (20 MJ kg,1) diets, each differing in l -carnitine content [0 (control), 300, 600, 900 and 1200 mg kg,1 diet]. At the end of the trial, fish grew from 19- to 23-fold in weight, from 8.4 g to a maximum of 191 g. Fish fed 300,600 mg l -carnitine had the highest specific growth rate (SGR, 3.69 and 3.72% day,1) and protein efficiency ratio (PER, 0.95 and 0.99), and the lowest feed conversion ratio (FCR, 1.4 and 1.3) than the other groups (P < 0.0001). SGR, PER and FCR were the poorest for fish fed 1200 mg l -carnitine, while fish fed the unsupplemented and 900 mg l -carnitine supplemented diet showed intermediate performance. Body lipid concentration decreased significantly from 5.8 to 5.1% (P < 0.0001) with dietary l -carnitine supplementation increasing from 0 to 300 mg. Energy content was significantly lower in fish fed the 900 and 1200 mg l -carnitine diet (5.8 MJ kg,1), when compared with the other treatment groups (6.4,6.6 MJ kg,1). The results indicated that feeding sturgeon on diets supplemented with 300 mg l -carnitine kg,1 diet improved growth performance, and stimulated protein-sparing effects from lipids. [source] Olive oil mill waste water as a replacement for fresh water in the manufacture of fired clay bricksJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2006Houda Mekki Abstract This paper describes the introduction of olive mill wastewater (OMW) to replace fresh water normally used in clay brick manufacture. OMW is recognised as the major agro-food industry pollutant in the Mediterranean/North African olive-growing region. The research involved adding OMW to laboratory-produced clay bricks following the same making procedure used at a collaborating Tunisian brick factory. The samples containing OMW were found to be comparable in forming/extrusion performance to a control product that used fresh water. If introduced at the factory scale, this innovation would allow a substantial volume of OMW to be recycled, saving on the fresh water currently used in the brick-forming process. During the subsequent brick drying operation, most of the OMW (,98% water) would be released as vapour. Once in the kiln, the remaining solids in the bricks (calorific value 21,23 MJ kg,1) would liberate additional heat, reducing the gross energy from fossil fuel currently required during firing. Copyright © 2006 Society of Chemical Industry [source] Energetics and morphology of sockeye salmon: effects of upriver migratory distance and elevationJOURNAL OF FISH BIOLOGY, Issue 3 2004G. T. Crossin Depending on population, wild Fraser River sockeye salmon Oncorhynchus nerka travel distances of <100 km to >1100 km and ascend elevations ranging from near sea-level to 1200 m to reach spawning areas. Populations embarking on distant, high elevation migrations (i.e. Early Stuart, Chilko and Horsefly populations) began their upriver spawning migrations with higher densities of somatic energy (c. 9·2 to 9·8 MJ kg,1) and fewer eggs (c. 3200 to 3800) than populations making shorter, low elevation migrations (i.e. Weaver and Adams; c. 7·1 to 8·3 MJ kg,1 gross somatic energy and c. 4300 to 4700 eggs). Populations making difficult upriver migrations also had morphologies that were smaller and more fusiform than populations making less difficult migrations, traits that may facilitate somatic energy conservation by reducing transport costs. Indeed, fish travelling long distances expended less somatic energy per unit of migratory difficulty than those travelling shorter distances (2·8 to 3·8 kJ v. 10,1400 kJ). Consistent with evolutionary theory, difficult migrations appear to select for energy efficiency but ultimately fish making more difficult migrations produce fewer eggs, even when differences in body length have been accounted for. Despite large among-population differences in somatic energy at the start of upriver migration, all populations completed migration and spawning, and subsequently died, with c. 4 MJ kg,1 of energy remaining, a level which may reflect a threshold to sustain life. [source] Characterisation of the leaf meals, protein concentrates and residues from some tropical leguminous plantsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 9 2006J Oluwasola Agbede Abstract Leaf meals (LMs) from freshly harvested leaves of butterfly pea (Centrosema pubescens), devil bean (Mucuna pruriens), flamboyant flower (Delonix regia), Bauhinia tomentosa, coast wattle (Acacia auriculiformis), quick stick (Glyricidia sepium) and ipil-ipil (Leucaena leucocephala) were analysed for their nutrient and anti-nutritional content. Then, leaf protein concentrates (LPCs) were produced from the leaves by fractionation and characterised along with the fibrous residues. On average, the LM contained 181 g kg,1 dry matter (DM) CP (range: 100,280 g kg,1 DM), 139 g kg,1 DM crude fibre (range: 77,230 g kg,1 DM) and 133 g kg,1 DM ether extract (range: 86,165 g kg,1 DM) while the gross energy averaged 17.0 MJ kg,1. On average, leaf protein fractionation enhanced the CP, ether extract and the gross energy in the LPC by 39.5%, 33.5% and 22.0%, respectively, while the crude fibre of the LMs was reduced by 41%, on average, in the LPCs. Fractionation reduced the mineral content of the leaves generally. The mean phytin content varied from 0.36 g kg,1 in LPCs to 0.86 g kg,1 in leaf meal, while the mean phytin-P content varied from 0.10 g kg,1 in LPCs to 0.24 g kg,1 in leaf meal. The total phenol levels in the LMs were reduced by 33.7% in the LPCs, on average. These results suggest that, while the LPCs from these plants could be used as protein supplements in non-ruminant feeds in regions where there is an acute shortage of plant protein, the LMs or LPC fibrous residues could be fed to ruminant animals. Copyright © 2006 Society of Chemical Industry [source] Nutritional evaluation of peas for ducksJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2004Charles M Nyachoti Abstract The nutritive value of four pea cultivars (AC Advantage, Carneval, CDC Mozart and Keoma) and soybean meal (SBM) was evaluated in a 102 h study with 48 male White Pekin ducks. All birds were tube-fed 25 g of dextrose at 24 and 30 h after feed withdrawal, then 25 g of each feedstuff was tube-fed to eight ducks at 48 and 54 h after feed withdrawal. Excreta were quantitatively collected during the next 54 h. Endogenous nitrogen, amino acids and energy per bird in the 54 h collection period were 1.06 ± 0.58 g, 0.047 ± 0.025 g and 0.098 ± 0.049 MJ respectively. There were differences (P < 0.05) in apparent amino acid digestibilities (AAAD) and true amino acid digestibilities (TAAD). On average, AAAD were 82.8, 82.0, 70.3, 82.4 and 77.7% and TAAD were 89.4, 89.2, 82.3, 89.5 and 85.3% for SBM, AC Advantage, Carneval, CDC Mozart and Keoma respectively. The nitrogen-corrected apparent and true metabolisable energy values did not differ among the pea diets and were 13.36 ± 0.071 and 14.59 ± 0.071 MJ kg,1 respectively. Respective values for SBM were 12.16 ± 0.16 and 13.39 ± 0.16 MJ kg,1 and both were lower (P < 0.05) than in peas. Copyright © 2004 Society of Chemical Industry [source] Growth, nitrogen gain and indispensable amino acid retention of pacu (Piaractus mesopotamicus, Holmberg 1887) fed different brewers yeast (Saccharomyces cerevisiae) levelsAQUACULTURE NUTRITION, Issue 3 2010R.O.A. OZÓRIO Abstract A feeding-and-digestibility trials were carried out to evaluate the efficacy of replacing fishmeal with brewers yeast Saccharomyces cerevisiae in diets of pacu, Piaractus mesopotamicus, juveniles. The feeding trial was conducted during 54 days with 450 fish (26.6 ± 1.7 g) testing six isonitrogenous (270 g kg,1 crude protein) and isoenergetic (19 MJ kg,1 crude energy) diets, with increasing yeast level to replace 0 (control), 30, 35, 50, 70 or 100% of dietary fishmeal. Growth performance and feed utilization increased with increasing dietary yeast level until 50% fishmeal replacement. Protein retention efficiency was higher in fish fed 35 and 50%. Protein digestibility and the fillet hue (the red/green chromaticity) were not significantly different among all treatments. Nitrogen gains were significantly improved in fish fed 35% replacement diet compared to fish fed the control diet. The retentions of indispensable amino acids tended to increase with increasing dietary yeast levels, with maximum retention at 35,50%. On the basis of our results, replacing 50% fishmeal by yeast in pacu diets successfully improved feed efficiency and growth performance, and reduced nitrogen losses, thereby reducing the nitrogen outputs from fish farms. [source] Investigations on the digestibility and metabolizability of the major nutrients and energy of maize leaves and barnyard grass in grass carp (Ctenopharyngodon idella)AQUACULTURE NUTRITION, Issue 3 2010E.B. DONGMEZA Abstract In the uplands of northern Vietnam, culture of grass carp contributes significantly to income and household food security of Black Thai farmers. Maize is one of the most important upland crops and barnyard grass is the most important weed in the paddy rice fields. Thus, these are frequently used by small-scale fish farmers as fish feed. An 8-week feeding trial was conducted simultaneously in a recirculation and in a respirometric system to determine the digestibility and metabolizability of the nutrients of maize leaves and barnyard grass, to assess their crude protein, lipid and energy conversion and to estimate the energy allocation in grass carp. The following diets were used: diet ,A' (reference diet) containing 39% crude protein with 19.8 MJ kg,1 gross energy; diets ,B', ,C' and ,D', which contained the same amount of the reference diet as the control diet, supplemented with a known amount of dried barnyard grass, dried maize leaves or fresh maize leaves, respectively. Five fish were assigned to each treatment in each experimental unit. Reference and test diets were fed to fish and faecal samples were collected and the oxygen consumption was measured in order to set up an energy budget of the fish over the whole experimental period. The weekly development of the body weight was recorded. The body weight gain of the fish fed diet D was significantly higher than that of the group fed diet A, which also in turn was significantly higher than that of fish fed diet B or C. The apparent digestibility coefficients (ADC) of nutrients and gross energy for the different experimental diets in fish kept in the aquaria were, for diets A, B, C and D respectively, 94.1%, 60.9%, 70.5% and 84.7% for protein, 91.3%, 60.7%, 76.8% and 71.8% for lipid; 95.9%, 44.5%, 60.6% and 69.1% for gross energy. The partial ADC of plant leaf ingredients were determined and barnyard grass and dried maize leaves were found to be not only poorly digestible but having negative impact on the digestibility of the reference diet, while fresh maize leaves were well digested. The results of the present study indicated that fresh maize leaves have a good potential to be used as supplement in diets for grass carp. [source] Growth performance and body composition of pacu Piaractus mesopotamicus (Holmberg 1887) in response to dietary protein and energy levelsAQUACULTURE NUTRITION, Issue 2 2010A.J.A. BICUDO Abstract Improper dietary protein and energy levels and their ratio will lead to increased fish production cost. This work evaluated effects of dietary protein : energy ratio on growth and body composition of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 ± 0.4 g) were fed twice a day for 10 weeks until apparent satiation with diets containing 220, 260, 300, 340 or 380 g kg,1 crude protein (CP) and 10.9, 11.7, 12.6, 13.4 or 14.2 MJ kg,1 digestible energy (DE) in a totally randomized experimental design, 5 × 5 factorial scheme (n = 3). Weight gain, specific growth rate increased and feed conversion ratio (FCR) decreased significantly (P < 0.05) when CP increased from 220 to 271, 268 and 281 g kg,1 respectively. Pacu was able to adjust feed consumption in a wide range of dietary DE concentration. Fish fed 260 CP diets showed best (P < 0.05) protein efficiency ratio and FCR with 11.7,12.6 MJ kg,1; but for the 380 CP-diets group, significant differences were observed only at 14.2 MJ kg,1 dietary energy level, suggesting that pacu favours protein as energy source. DE was the chief influence on whole body chemical composition. Minimum dietary protein requirement of pacu is 270 g kg,1, with an optimum CP : DE of 22.2 g MJ,1. [source] The interactive effects of dietary protein and energy on feed intake, growth and protein utilization of juvenile mulloway (Argyrosomus japonicus)AQUACULTURE NUTRITION, Issue 1 2010I. PIROZZI Abstract The objectives of this study were to describe the interactive effects of varying digestible protein (DP) and digestible energy (DE) contents on the feed intake, growth, protein utilization and whole body composition of juvenile mulloway (Argyrosomus japonicus) and to determine the optimal DP : DE ratio for growth. This was achieved by feeding mulloway diets containing one of four different DP levels (250,550 g kg,1) at two DE levels (16 or 21 MJ kg,1). Juvenile mulloway were stocked at each of two different sizes (70 or 200 g) in triplicate groups for each dietary treatment and fed twice daily to apparent satiation over 58 days. The results indicated that feed intake was not governed solely by energy demands but was also dependant on the DP content of the diet. Protein utilization did not improve with diets containing decreasing protein and increasing lipid content indicating that mulloway have a limited capacity to spare DP. Optimal DP content was found to be 444,491 g kg,1 depending on the DE content of the diet and the size of mulloway and is within the range reported for other sciaenid species. The use of formulated diets with 28.6 g of DP MJ DE,1 will achieve optimal growth and protein deposition for 70,275 g mulloway. [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] Effects of canola meal on physiological and biochemical parameters in rainbow trout (Oncorhynchus mykiss)AQUACULTURE NUTRITION, Issue 2 2008A. SHAFAEIPOUR Abstract Rainbow trout (initial body weight 4.16 ± 0.25 g) were fed diets [crude protein 420 g kg,1; gross energy 18.7 MJ kg,1 dry matter (DM); crude fat 110 g kg,1] containing graded levels of either a canola meal (crude protein 350 g kg,1 DM) supplemented with DL-methionine as partial fish meal protein. A growth trial was conducted over 16 weeks at a water temperature of 12 ± 1 °C. At the end of the growth trial, in addition to body composition analyses, plasma tri-iodothyronine (T3) and thyroxine (T4), cholesterol and liver fatty acid composition were measured. Replacement of fish meal with canola meal (100,570 g kg,1 replacement) did not affect on growth performance. At 16th week, plasma cholesterol levels were reduced in fish fed all diets in comparison with 8th week. Plasma T4 levels were significantly higher in the canola meal-fed fish sampled after 16 weeks, but no significant differences in T3 levels were obtained (P > 0.05). Proximate compositions were affected by dietary treatments. The liver fatty acid composition reflected that of the diet with a higher level of polyunsaturated (n-6) fatty acids in fish fed diet canola meal and a higher content in n-3/n-6 ratio in fish fed diet without canola meal. These studies show that canola meal has potential to replace substantial levels of fish meal in diets for carnivorous fish without compromising performance. [source] The olive oil by-product in ,rainbow trout Onchorynchus mykyss (Walbaum)' farming: productive results and quality of the productAQUACULTURE RESEARCH, Issue 10 2010Benedetto Sicuro Abstract The aim of this work is to investigate olive oil by-product [vegetation water (VW)] inclusion in rainbow trout diet and its effect on the productive traits and the quality of the product. Two levels of VW inclusion were used and one control group was included. Fish diets were isonitrogeonous (crude protein 40%) and isoenergetic (18 MJ kg,1 DM). Two thousand and four hundred rainbow trout were used. An in vivo digestibility experiment was performed in order to determine diets' digestibility. All the fish diets and fillets were analysed to determine the proximate and fatty acid composition. On final fish fillet, lipid oxidation was determined at 0, 24, 48, 72, 96 and 192 h of storage using the 2-thiobarbituric acid method (thiobarbituric acid reactive substances). Aroma analyses on the final cooked and raw fillet were performed using an electronic nose. The VW inclusion partially reduced protein digestibility. The fish growth varied between 1.08% and 1.1% day. The supplemental level of VW led to a better antioxidant status of fish fillet, in particular, in the fillet sample after 72 h of fillet conservation. Principal component analysis in raw and cooked fish fillet indicates that the VW inclusion in the fish diet led to aroma modification on fish fillet. [source] Impact of digestible energy levels at three different dietary amino acid levels on growth performance and protein accretion in Atlantic salmonAQUACULTURE RESEARCH, Issue 3 2010Adel El-Mowafi Abstract Nine experimental feeds were prepared, having two different digestible energy levels (DE, 19.5 and 21.5 MJ kg,1) and three different amino acid levels (90%, 100% and 110%), and formulated with two alternative strategies (protein and fat vary freely or only protein varies freely). The design was not balanced and thus the 110% amino acid profile was only studied at 19.5 MJ kg,1 DE. Atlantic salmon (Salmo salar) with a mean body weight of 449±19 g were distributed in 24 tanks and were fed each of the experimental diets for a period of 90 days. The fish were fed three times daily and uneaten feed was collected. Increasing the dietary DE energy from 19.5 to 21.5 MJ kg,1 and the amino acid level from 90% to 100% of the requirement increased the feed intake and growth performance in Atlantic salmon. Increasing the amino acid level from 90% to 100% had a positive effect on the feed intake, growth and protein accretion. Also, the mRNA levels of insulin-like growth factor I in muscle tissues pointed to this positive effect when the amino acid level increased. High probabilities were associated with a negative effect on the feed intake of reducing the amino acid level regardless of the DE level. It is recommended that the balanced amino acid level should not be adjusted by the same percentage rate as dietary energy, and possibly should not be reduced at all in order to maintain optimum performance and profitability. [source] Haematological modulation and growth of Labeo rohita fingerlings: effect of dietary mannan oligosaccharide, yeast extract, protein hydrolysate and chlorellaAQUACULTURE RESEARCH, Issue 1 2009Simi Rose Andrews Abstract The present study was conducted for 60 days to delineate the efficacy of various dietary immunomodulators like mannan oligosaccharide (MOS), yeast extract (YE), protein hydrolysate (PH) and chlorella (CL) in Labeo rohita fingerlings. Five hundred and eighty-five L. rohita fingerlings (average weight: 4.15 ± 0.07 g) were randomly distributed in 13 treatment groups with each of three replicates. Thirteen semi-purified isonitrogenous (crude protein 324.7,332.5 g kg,1) and isocaloric (17.66,17.80 MJ kg,1) diets were prepared with three graded levels (1%, 2% or 4%) of immunostimulants, except the control. At the end of the feeding trial, weight gain%, specific growth rate, feed conversion ratio, leucocyte count, erythrocyte count, haemoglobin content, serum protein, globulin, albumin,globulin ratio, nitroblue tetrazolium (NBT) value and survival percentage were evaluated. Growth was significantly higher in the MOS-fed group. All the immune parameters studied were also recorded higher in the MOS 1%-supplemented group. The survival percentage after challenging with Aeromonas hydrophila was higher (P<0.05) in the MOS-, YE- and PH-fed groups and the lowest in the CL-treated group. It can be concluded that dietary supplementation of MOS at a 1% dietary level promotes growth and survival in L. rohita fingerlings. In contrast, higher inclusion levels of immunostimulants led to an immunosuppressive effect in L. rohita fingerlings. [source] Effects of dietary protein levels on the growth performance, digestive capacity and amino acid metabolism of juvenile Jian carp (Cyprinus carpio var. Jian)AQUACULTURE RESEARCH, Issue 9 2009Yong Liu Abstract This experiment was conducted to evaluate the effects of protein levels on the growth performance, digestive capacity and amino acid metabolism of juvenile Jian carp. Brown fish meal was used as the sole protein source in the present study. Six isoenergetic experimental diets containing 14.4 MJ kg,1 of digestible energy and 220,495 g crude protein kg,1 diets were fed to triplicate groups of 50 fish with a mean initial weight of 16.67 ± 0.01 g for 45 days. Per cent weight gain (PWG) and feed efficiency ratio (FER) improved with an increase in the dietary protein levels up to 330 g kg,1 diet. The condition factor, relative gut length, intestinal folds height, hepatopancreas and intestine protein content improved with an increase in the protein levels up to 330,385 g kg,1 diet. Trypsin, creatinkinase, Na+, K+ -ATPase and alkaline phosphatase activities generally followed the same tendency as that of growth parameters. Amylase and ,-glutamyl transpeptidase (,-GT) activities were negatively correlated with increasing protein levels from 220 to 330 g kg,1 diet, and no differences were found thereafter. Lipase activity was unaffected by protein levels. Lactobacillus amount was increased with protein levels up to 275 g kg,1 diet, while Aeromonas amount followed the opposite pattern. Escherichia coli amount was not influenced by dietary protein levels. Glutamate,oxaloacetate transaminase (GOT) activities in the hepatopancreas and plasma ammonia concentration (PAC) were not influenced by protein levels between 220 and 275 g kg,1 diet, but significantly increased with increasing protein levels from 275 to 440 g kg,1 diet, and remained similar thereafter. Glutamate,pyruvate transaminase (GPT) activities significantly increased with protein levels >275 g kg,1 diet. Based on the broken-line model, the dietary protein requirement for PWG of Jian carp (16.7,55.0 g) was estimated to be 341 g kg,1 diet with a digestible energy of 14.4 MJ kg,1 diet. [source] Growth and haematology of pacu, Piaractus mesopotamicus, fed diets with varying protein to energy ratioAQUACULTURE RESEARCH, Issue 4 2009Álvaro José De Almeida Bicudo Abstract Haematopoiesis and blood cells' functions can be influenced by dietary concentration of nutrients. This paper studied the effects of dietary protein:energy ratio on the growth and haematology of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5±0.4 g) were fed twice a day for 10 weeks until apparent saciety with diets containing 220, 260, 300, 340 or 380 g kg,1 crude protein (CP) and 10.88, 11.72, 12.55, 13.39, 14.22 MJ kg,1 digestible energy (DE) in a totally randomized experimental design, 5 × 5 factorial scheme (n=3). Weight gain and specific growth rate were affected (P<0.05) by protein level only. Protein efficiency ratio decreased (P<0.05) with increasing dietary protein at all levels of dietary energy. Daily feed intake decreased (P<0.05) with increasing dietary energy. Mean corpuscular haemoglobin concentration was affected (P<0.05) by DE and interaction between dietary CP and DE. Total plasma protein increased (P<0.05) with dietary protein and energy levels. Plasma glucose decreased (P<0.05) with increasing dietary protein. The CP requirement and optimum protein:energy ratio for weight gain of pacu fingerlings, determined using broken-line model, were 271 g kg,1 and 22.18 g CP MJ,1 DE respectively. All dietary CP and DE levels studied did not pose damages to fish health. [source] Evaluation of pea protein isolate as alternative protein source in diets for juvenile tilapia (Oreochromis niloticus)AQUACULTURE RESEARCH, Issue 5 2007Carsten Schulz Abstract To evaluate isolated pea protein as feed ingredient for tilapia (Oreochromis niloticus) juveniles, triplicate groups were fed with four isonitrogenous [crude protein: 421.1,427.5 g kg,1 in dry matter (d.m.)] and isoenergetic (gross energy: 20.46,21.06 MJ kg,1 d.m.) diets with varying protein sources for 8 weeks. Fish meal-based protein content of diets was substituted with 0% (diet 100/0=control group), 30% (diet 70/30), 45% (diet 55/45) and 60% (diet 40/60) isolated pea protein. Tilapia juveniles with an initial body weight of 2.23,2.27 g were fed in average at a level of 5% of their body weight per day. Highest individual weight gain (WG: 21.39 g) and specific growth rate (SGR: 4.21% day,1) and best feed conversion ratio (FCR: 0.90) were observed in tilapia fed diet 100/0, followed by fish-fed diet 70/30 (WG: 19.09 g; SGR: 4.03% day,1; FCR: 0.98), diet 55/45 (WG: 16.69 g; SGR: 3.80% day,1; FCR: 1.06) and diet 40/60 (WG: 16.18 g; SGR: 3.74% day,1; FCR: 1.06). Although fish fed diet 100/0 showed the best performance, inclusion of 30% protein derived from pea protein isolate resulted in a growth performance (in terms of WG and SGR) that did not differ significantly from diet 100/0 in contrast to fish fed diet 55/45 and 40/60. Crude ash content in the final body composition of the experimental fish decreased with increasing dietary pea protein content, while crude protein and lipid content remained equal between the groups. Significant decreasing growth performance and body ash incorporation of tilapia at higher inclusion levels seem to be mainly related to the dietary amino acid profile and phytic acid contents. [source] | |||||||||||||