kJ G (kj + g)

Distribution by Scientific Domains

Selected Abstracts

Seasonal field metabolic rate and dietary intake in Arabian Babblers (Turdoides squamiceps) inhabiting extreme deserts

A. Anava
Abstract 1.,Arabian Babblers (Turdoides squamiceps Cretzsch.; mean adult body mass = 72·5 g) inhabit extreme deserts of Israel. They consume invertebrates and fruits and, at least at our study site, do not drink. It was hypothesized that babblers (1) in general, use relatively less energy and water than other birds of its body mass; and (2) consume a more water-rich diet (mainly fruits) in summer and more energy-rich diet (mainly invertebrates) in winter. Doubly labelled water was used to determine seasonal field metabolic rate (FMR) and water influx rate (WIR) and to estimate dietary selection in free-living Arabian Babblers. 2.,Babblers in winter weighed significantly more than in summer, and males weighed more than females in both seasons. Tritiated water (TOH) space, as a proportion of body mass, was higher in males than in females in summer but no difference between sexes was found in winter. Males in summer had a higher TOH space, proportionally, than males in winter but there was no difference between seasons in females. Mass-specific WIR did not differ between sexes in any season and averaged 0·475 ml g,1 d,1 in winter which was significantly higher than the 0·283 ml g,1 d,1 in summer. 3.,The mean daily energy expenditure of the babblers did not differ either between seasons or between sexes within seasons and averaged 1·61 kJ g,1 d,1 in winter and 1·68 kJ g,1 d,1 in summer. It was calculated that each babbler consumed an average of 5·09 g dry matter invertebrates and 1·83 g dry matter fruits in summer (for a 68·2-g bird; mean adult body mass in summer) and 3·49 g dry matter invertebrates and 6·61 g dry matter fruits in winter (for a 76·9-g bird; mean adult body mass in winter). 4.,When compared with other avian species, FMR and WIR of babblers were lower than bird species in general, but were similar to those of other desert birds. It was calculated that proportional dietary intake, on a dry matter basis, included 0·79 insects and 0·21 fruits in summer and 0·35 insects and 0·65 fruits in winter. Therefore, the babblers consumed a relatively energy-rich diet in summer and water-rich diet in winter which refuted our hypothesis. Most of the metabolizable energy was provided by invertebrates in both seasons; invertebrates provided more water in summer but fruits provided more in winter. [source]

Sex differences in grey seal diet reflect seasonal variation in foraging behaviour and reproductive expenditure: evidence from quantitative fatty acid signature analysis

Summary 1Intraspecific variation in diet can be an important component of a species niche breadth. We tested the hypothesis that sex differences in seasonal foraging behaviour and energy storage of sexually size dimorphic grey seals Halichoerus grypus (Fabrisius 1971) are reflected in differences in the diet and niche breadth. Diet composition was estimated for 496 adult (226 males, 270 females) and 91 juvenile (46 males/45 females; all 6 months old) grey seals sampled between 1993 and 2000 using quantitative fatty acid signature analysis. Niche breadth and overlap were estimated using the Shannon,Weaver diversity index (H,) and the Morisita,Horn index (CH), respectively. 2Sand lance Ammodytes dubius (Reinhardt 1837) and redfish Sebastes sp. (Cuvier 1829) accounted for a high proportion of the diet in both sexes and age groups. However, the diets of adult males were significantly more diverse across all seasons (H,: males 0·36 ± 0·007 vs. females 0·28 ± 0·007) and less energy dense in spring (male 5·3 ± 0·07 kJ g,1 vs. females 5·6 ± 0·09 kJ g,1) than those of adult females. 3Season and sex explained most of the observed variation in adult diets, but there were significant sex,season interactions. These differences were most evident during the post-breeding (spring) foraging period when energy acquisition is important to female recovery of nutrient stores needed to support pregnancy. Females selected fewer and higher quality prey species in spring than males. 4There were no sex differences in the diets of juvenile grey seals. Although many of the species overlapped with those eaten by adults, juvenile niche breadth (H,: 0·41 ± 0·014, n = 91) was significantly broader than that of adults (H,: 0·30 ± 0·011, n = 115). Juvenile diets were also of lower energy density (5·3 ± 0·04 kJ g,1) than those of adults (5·6 ± 0·09 kJ g,1), suggesting less selectivity in these young and relatively naïve predators. 5Sex-specific seasonal changes in diet correspond to seasonal changes in diving behaviour and rate of body energy accumulation of adult males and females. Sex-specific reproductive requirements appear to be a primary factor generating the intraspecific variation in the seasonal foraging ecology of this large marine carnivore. However, sex differences in the breadth and energy content of diets also suggest the influence of body-size dimorphism as a factor shaping the diet of this species. [source]

Effect of inclusion of blue-green algae meal on growth and accumulation of microcystins in gibel carp (Carassius auratus gibelio)

M. Zhao
Summary Six isonitrogenous (crude protein content: 38%) and isoenergetic (gross energy content: 17 kJ g,1) diets were formulated to investigate the effects of inclusion of blue-green algae meal on gibel carp (Carassius auratus gibelio). In each diet, 15% of the protein was supplied by fishmeal; the remainder was supplied by soybean meal and blue-green algae meal. Diet 1 was used as control with no blue-green algae meal whereas the content in diets 2,6 was 15.15, 29.79, 44.69, 59.58 and 74.48%, respectively. Each diet was fed to five groups of gibel carp for 12 weeks in a flow-through system. Final body weight and specific growth rate (SGR) of fish fed diet 5 were significantly lower than the control diet (P < 0.05). Mortality of gibel carp increased with increase in algae meal inclusion (P < 0.05), but there was no significant difference between fish fed diets 3,6 (P > 0.05). Feed conversion efficiency (FCE) decreased with the increase in algae meal inclusion (P < 0.05). Fish-fed diet 6 showed the highest feeding rate (P < 0.05), while there were no significant differences among the other groups (P > 0.05). Apparent digestibility coefficient of dry matter, protein, and energy decreased with increasing algae meal inclusion in the diets (P < 0.05). Aspartate aminotransferase (GOT) activity in the liver was not significantly different among groups (P > 0.05). Liver alanine aminotransferase (GPT) activity of fish-fed diets 4, 5 and 6 was significantly lower than the control diet (diet 1; P < 0.05). Microcystins in the muscle, liver, gallbladder, and spleen increased with increasing algae inclusion (P < 0.05). [source]

Energy density of anchovy Engraulis encrasicolus in the Bay of Biscay

J. Dubreuil
The energy density (ED) of anchovy Engraulis encrasicolus in the Bay of Biscay was determined by direct calorimetry and its evolution with size, age and season was investigated. The water content and energy density varied seasonally following opposite trends. The ED g,1 of wet mass (MW) was highest at the end of the feeding season (autumn: c. 8 kJ g,1MW) and lowest in late winter (c. 6 kJ g,1MW). In winter, the fish lost mass, which was partially replaced by water, and the energy density decreased. These variations in water content and organic matter content may have implications on the buoyancy of the fish. The water content was the major driver of the energy density variations for a MW basis. A significant linear relationship was established between ED g,1 (y) and the per cent dry mass (MD; x): y =,4·937 + 0·411x. In the light of the current literature, this relationship seemed to be not only species specific but also ecosystem specific. Calibration and validation of fish bioenergetics models require energy content measurements on fish samples collected at sea. The present study provides a first reference for the energetics of E. encrasicolus in the Bay of Biscay. [source]

Light use efficiency of dry matter gain in five macro-lichens: relative impact of microclimate conditions and species-specific traits

K. Palmqvist
ABSTRACT Relations between irradiance (I) and lichen growth were investigated for five macro-lichens growing at two sites in Sweden. The lichens represented different mycobiont,photobiont associations, two morphologies (foliose, fruticose) and two life forms (epiphytic, terricolous). The lichens were transplanted at two geographically distant sites in Sweden (1000 km apart) from Sept 1995 to Sept 1996 in their typical microhabitats, where microclimate and growth were followed. Between April/May and Sept 96, the terricolous species had a dry matter gain of 0·2 to 0·4 g (g DW),1 and the epiphytes 0·01 to 0·02 g (g DW),1. When related to area, growth amounted to 30 to 70 g m,2 for the terricolous species and to 1 to 4 g m,2 for the epiphytes. There was a strong correlation between growth and intercepted irradiance when the lichens were wet (Iwet), with 0·2 to 1·1 g lichen dry matter being produced per MJ solar energy. Across the 10 sets of transplants, light use efficiencies of dry matter yield (e) ranged between 0·5 and 2%, using an energy equivalent of 17·5 kJ g,1 of lichen dry matter. The higher productivity of the terricolous species was due to longer periods with thallus water contents sufficient for metabolic activity and because of the higher mean photon flux densities of their microhabitat. A four-fold difference in photosynthetic capacity among the species was also important. It is concluded that lichen dry matter gain was primarily related to net carbon gain during metabolically active periods, which was determined by light duration, photon flux density and photosynthetic capacity. [source]

Influence of dietary lipid/protein ratio on survival, growth, body indices and digestive lipase activity in Snakehead (Channa striatus, Bloch 1793) fry reared in re-circulating water system

Abstract Nine isoenergetic (18.5 kJ g,1) diets were formulated in a 3 × 3 factorial design to contain three protein levels (350, 400 and 450 g kg,1) for each of three lipid levels (65, 90 and 115 g kg,1), respectively, and fed twice daily for 8 weeks to fish of mean initial weight 3.34 ± 0.02 g reared in a re-circulatory water system. Temperature, pH and dissolved oxygen (DO) were maintained within the range 28,30 °C, 5.6,6.8 and 4.82,6.65 mg L,1 respectively throughout. Results show that fish survival was better in the groups fed 65 g kg,1 lipid while growth performance (% weight gain, WG; specific growth rate, SGR) and nutrient utilization (feed conversion ratio, FCR; protein efficiency ratio, PER; protein intake, PI) in the 65/450 and 90/450 g kg,1 treatments were similar and significantly (P < 0.05) higher than in fish fed the other lipid/protein ratio combinations. The body indices monitored (Hepatosomatic index, HSI and viscerosomatic index, VSI) were similar among the treatments whereas intestinal lipase activity was not significantly (P < 0.05) affected by increase in dietary lipid and protein levels. Carcass composition showed that dietary protein level affected body protein content positively in the 65 and 90 g kg,1 lipid treatments, but dietary lipid level did not affect body lipid content. A lipid/protein ratio of 65/450 g kg,1 is considered adequate for good growth performance and survival of Channa striatus fry. [source]

Effects of dietary protein level on growth, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis

Abstract A feeding trial was conducted using isoenergetic practical diets to evaluate the effects of the dietary protein level on growth performance, feed utilization and digestive enzyme activity of the Chinese mitten crab, Eriocheir sinensis. Four experimental diets were formulated containing 250, 300, 350 and 400 g kg,1 protein and 16 kJ g,1 gross energy. Each diet was randomly assigned to triplicate groups of juvenile crab with mean initial body weight 3.56 ± 0.16 g and mean shell width 15.31 ± 0.06 mm. Juvenile crab were reared in indoor flow-through system consisting of 12 plastic tanks (1.0 m × 0.6 m × 0.5 m) and fed diets twice daily at 6,8% of body weight for 12 weeks. Performance was judged on the basis of growth (specific growth rate of weight, SGRG; specific growth rate of shell width, SGRSW), feed conversion ratio (FCR) and protein efficiency ratio (PER). A decreased FCR was observed with increasing dietary protein levels. Both SGRG and SGRSW significantly increased with increasing dietary protein levels up to 350 g kg,1, whereas there were no significant differences for protein levels from 350,400 g kg,1. Application of broken line regression analysis to SGRG provided an estimate of 347.8 g kg,1 dietary protein for maximal growth. The highest PER was observed in crab fed the diet containing 350 g kg,1 protein (P < 0.05). The percent survival was not affected (P > 0.05) by the different dietary treatments. No significant differences were observed in the apparent digestibility coefficients of crude lipid and dry matter among dietary treatments (P > 0.05). However, the apparent digestibility coefficients of crude protein and energy in crab fed different protein levels significantly increased with increasing dietary protein level (P < 0.05). Both amylase and protease activities in the intestine of E. sinensis were studied. The amylase activity decreased significantly (P < 0.05) with increased dietary protein level and protease activity increased. Regression analysis showed a negative effect of inclusion of dietary protein level on amylase activity (P < 0.05). However, protease activities were found to be positively correlated (P < 0.05) with dietary protein level. The protein content of the crab significantly increased with dietary protein levels up to 350 g kg,1 (P < 0.05), but no significant differences (P > 0.05) were founded with protein levels higher than 350 g kg,1. [source]

Effect of dietary carbohydrate-to-lipid ratios on growth performance, body composition, nutrient utilization and hepatic enzymes activities of herbivorous grass carp (Ctenopharyngodon idella)

Abstract Six isonitrogenous (390 g kg,1) and isoenergetic (16.2 kJ g,1) diets with varying carbohydrate : lipid (CHO : L) ratios (202.5,1.74), were fed to triplicate groups of 25 fish in indoor recirculation system. Over 8-week-growth trial, best weight gain (WG), specific growth rate, feed conversion ratio, protein efficiency ratio and protein production value (P < 0.05) were observed in fish-fed diets with CHO : L ratio of 7.5. Fish fed either the lowest (1.7) or highest (202.5) CHO : L ratio tended to produce lower (P < 0.05) growth and feed conversion efficiencies. The values of viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio increased as dietary CHO : L ratios decreased. There were no significant differences in whole body and liver crude protein among dietary treatments. Whole body and liver lipid increased as CHO : L ratios decreased. Plasma cholesterol and triacylglyceride levels increased linearly as dietary CHO : L ratios decreased. Activities of glucokinase and pyruvate kinase were stimulated by elevated levels of dietary carbohydrate; however, activities of lipase (LPS) and alkaline phosphatase were stimulated by elevated levels of dietary lipid. Based on a second-order polynomial regression analysis of WG against dietary carbohydrate and lipid levels, 275 g kg,1 of carbohydrate and 59 g kg,1 of lipid, corresponding to a CHO : L ratio of 4.7, in a diet holding 390 g kg,1 of crude protein and 16.3 kJ g,1 of gross energy, proved to be optimal for grass carp. These results indicated that utilization of dietary lipid and carbohydrate was moderate in grass carp, but the fish were a little more capable of utilizing lipid compared with carbohydrate. [source]

Nutritional evaluation of waste date fruit as partial substitute for soybean meal in practical diets of juvenile Nile tilapia, Oreochromis niloticus L.

Abstract The potential of waste date meal (WDM; low-quality date palm, Phoenix dactylifera L.) as a carbohydrate source in formulated diets for Nile tilapia was evaluated. Four isocaloric-practical diets (15.7 kJ g,1) were formulated incorporating WDM at 0, 100, 200 and 300 g kg,1 levels as partial substitutes for soybean meal (SBM). These were designated D0 [284 g crude protein (CP) and 383 g carbohydrate (CHO) kg,1 diet], D1 (279 g CP and 446 g CHO kg,1 diet), D2 (207 g CP and 495 g CHO kg,1 diet) and D3 (175 g CP and 578 g CHO kg,1 diet). Each diet was fed to three replicate groups of 30 fish [20.20 ± 0.09 g (±SE)] for 75 days. No feed-related mortality was observed during the entire experimental period. Final body weight (FBW) and specific growth rate (SGR) in the different treatments were statistically not significantly different (P > 0.05). Protein efficiency rate (PER) was lowest in diet D0 and increased with decrease of SBM content (D1,D3). A significant increase in whole body lipid content was recorded in fish fed diets D2 and D3. Results showed that WDM could be a substitute for SBM up to 300 g kg,1 in practical Nile tilapia diets without compromising growth. [source]

Optimum dietary soybean meal level for maximizing growth and nutrient utilization of on-growing gilthead sea bream (Sparus aurata)

Abstract Six isonitrogenous [450 g kg,1 crude protein (CP)] and isoenergetic diets (23 kJ g,1) with six levels of defatted soybean meal inclusion (0, 132, 263, 395, 526 and 658 g kg,1) in substitution of fish meal were evaluated in gilthead sea bream of 242 g initial weight for 134 days. Fish fed diets S0, S13, S26 and S39 had a similar live weight (422, 422, 438 and 422 g, respectively) but fish fed diets S53 and S66 obtained the lowest final weight (385 and 333g, respectively), and similar results were presented in specific growth rate (SGR). Fish fed diets S53 and S66 also obtained the highest feed conversion ratio (FCR). Quadratic multiple regression equations were developed for SGR and FCR which were closely related to dietary soybean level. The optimum dietary soybean levels were 205 g kg,1 for maximum SGR and 10 g kg,1 for minimum FCR. Sensorial differences were appreciated by judges between fish fed S0 and S39 soybean level, but after a re-feeding period of 28 days with diet S0, these differences disappeared. [source]

Substituting fish meal with poultry by-product meal in diets for black Sea turbot Psetta maeotica

Abstract A 60 days feeding experiment was carried out with Black Sea turbot Psetta maeotica to determine the amount of poultry by-product meal (PBM) that could replace fish meal (FM) in formulated diets without reducing growth performance. Juvenile Black Sea turbot (initial average weight, 30 g) were fed five isoenergetic (gross energy, 20.5 ± 0.21 kJ g,1 diet) and isonitrogenous diets (protein content, 550 ±,0.35 g kg,1). The control diet used white FM as the sole protein source, the other four diets were prepared to replace FM protein at levels of 25%, 50%, 75% and 100% with PBM. The fish readily accepted all experimental diets and no mortality were recorded during the trial. There were no significant differences in growth performance of turbot (P < 0.05) fed the diets with 25% and 50% replacement levels compared with fish offered the control diet (100% FM), however, final body weight and specific growth rate values in the 50% replacement diet were about 8% lower than those of the control. Total nitrogen excretion in fish fed 50% replacement diet were about 10% higher than the control group, even though these parameters were not found to be statistically different. At the levels of 750 and 1000 g kg,1 of the protein, PBM inclusion caused a severe decrease in growth performance, feed utilization, protein efficiency ratio and per cent nitrogen retention. The results in the present study indicate that up to 25% of FM protein can be replaced by PBM protein without causing reduction in growth performance, nutrient utilization and nitrogen retention. [source]

Dietary energy requirement of piracanjuba fingerlings, Brycon orbignyanus, and relative utilization of dietary carbohydrate and lipid

Abstract Ten isonitrogenous casein,gelatin-based diets were formulated to contain five estimated metabolizable energy concentrations (10.92, 12.29, 13.63, 14.82 and 16.16 kJ g,1) at two carbohydrate-to-lipid ratios (CHO : L, 5.3 and 12.8, g : g) in a 5 × 2 factorial arrangement. Each diet was assigned to triplicate groups of 11 piracanjuba fingerlings (5.25 ± 0.14 g) and fed to apparent satiation twice a day for 90 days. Higher daily weight gain was obtained by fish fed the 13.63 kJ g,1 diets for both CHO : L ratios. There was a significant reduction of feed consumption when dietary energy concentration increased above 13.63 kJ g,1. Feed conversion ratio and apparent net energy retention improved as dietary energy increased. Apparent net protein retention tended to be lower in the highest and lowest dietary energy concentrations. The results suggest that dietary lipid energy was more efficiently utilized by piracanjuba fingerlings than carbohydrate energy. Body composition and hepatosomatic index (HSI) were not influenced by dietary CHO : L ratio. However, an increase in dietary energy concentration beyond 13.63 kJ g,1 resulted in a significant increment in lipid deposition, while body moisture and HSI decreased. Our findings indicate that at 300 g kg,1 dietary crude protein, a CHO : L ratio of 5.3 is recommended for piracanjuba, and the required energy is either 13.63 kJ g,1 if raised for aquaculture or 14.82 kJ g,1 if destined to stock enhancement. [source]

Soybean protein concentrate as a protein source for turbot Scophthalmus maximus L.

O.J. Day
In the first of two experiments, the effect of a gradual substitution of dietary fish meal with soybean protein concentrate (SPC) on growth, feed consumption and protein digestibility was examined in 13 g turbot Scophthalmus maximus. Five isonitrogenous and isoenergetic diets (50% protein and 22 kJ g,1) containing SPC at protein replacement levels of 0, 25, 50, 75 and 100% were offered by hand twice daily. Growth rates of fish fed diets with zero and 25% replacement were not significantly different, with SGRs of 2.47 and 2.28, respectively. At higher replacement levels, growth rates decreased significantly with SGRs of 2.00, 1.33 and 0.68, respectively. Feed conversion ratios increased with soya replacement, with values of 0.68, 0.75, 0.89, 1.27 and 2.32, respectively, although there was no significant difference between the first two. Feed consumption rates remained constant up to 50% replacement, above which they decreased significantly, possibly because of reduced diet palatability. Apparent protein digestibility (APD) was not affected by the incorporation of SPC and ranged from 82.8 to 87.5%. Results suggest that protein catabolism increases in SPC-rich diets, possibly because of rapid assimilation and utilization of the methionine supplement. In the second experiment, the importance of amino acid supplements and the beneficial effects of protecting these, either by coating them in protein or incorporating them in a protein,lipid emulsion, was investigated. Growth data provided some indication that the utilization of SPC may be improved by incorporating the methionine and lysine supplement in a protein,lipid emulsion prior to diet preparation, although this finding was not found to be statistically significant (0.1 < P < 0.2). [source]

Partial substitution of fish meal with soybean and cottonseed meals in diets for African bonytongue, Heterotis niloticus (Cuvier, 1829) fingerlings: effects on growth, feed efficiency and body composition

Serge-Eric Monentcham
Abstract A feeding trial was conducted to examine the suitability of soybean meal (SBM) and cottonseed meal (CSM) as a partial substitute for the dietary protein supplied by fish meal for H. niloticus fingerlings. Fish were fed with four isonitrogenous (350 g kg,1 crude protein) and isoenergetic (18.8 kJ g,1 GE) diets in which fish meal protein was gradually replaced by plant protein from a mixture of SBM and CSM (0%, 25%, 50% and 75% in diets 1, 2, 3 and 4 respectively). Triplicate groups of fingerlings H. niloticus (mean weight of 5 g) were handfed twice daily to apparent satiation for 60 days inside net hapas. Growth performances (SGR varied from 3.09% to 3.16% day,1) of fingerlings fed diets containing 0%, 25% and 50% plant protein were not significantly different (P>0.05). At 75% fish meal substitution, growth and feed utilization efficiency indicators were significantly reduced (P<0.05). The carcass composition were also significantly (P<0.05) affected by the replacement level of fish meal, except dry matter and ash. Results suggest that the dietary fish meal protein could efficiently be substituted by a mixture of soybean and cottonseed meals up to 50%, without adverse effects on maximal growth in practical diets for H. niloticus fingerlings. [source]

Growth, feed utilization and body composition of African bonytongue, Heterotis niloticus, fingerlings fed diets containing various protein and lipid levels

Serge-Eric Monentcham
Abstract In order to evaluate the effects of dietary protein and lipid levels on the growth, feed utilization and body composition of Heterotis niloticus fingerlings, a factorial experiment with three replicates was conducted. Six experimental diets containing three crude protein levels (28%, 32% and 36%) and two crude lipid levels (6% and 13%) were tested. Heterotis niloticus (2.34 g) were fed with the diets to apparent satiation, twice a day. For 56 days, weight gain (WG), specific growth rate (SGR), feed efficiency (FE) and protein retention (PR) were significantly affected by dietary protein and dietary lipid levels respectively (P<0.01). The highest WG, SGR and FE were observed for fingerlings fed the diet containing 36% protein and 6% lipid, but no significance difference was found between groups fed with the following diets: P28L13 (28% protein and 13% lipid), P32L6, P32L13 and P36L13. A significant interaction between dietary protein and lipid was observed for WG, SGR, FE and PR. The whole-body protein, lipid, moisture and ash content were not significantly affected by dietary lipid levels, but body protein and lipid content were significantly affected by dietary protein. The dietary protein-sparing effect was clearly demonstrated when the dietary energy of lipid increased from 17 to 19.6 kJ g,1 at 28% crude protein on H. niloticus. [source]

Influence of different sources and levels of dietary protein and lipid on the growth, feed efficiency, muscle composition and fatty acid profile of Snakehead Channa striatus (Bloch, 1793) fingerling

Mohammed Aliyu-Paiko
Abstract Nine isoenergetic (18.5 kJ g,1) diets were formulated, in a 3 × 3 factorial design, by varying three levels of dietary protein (350, 400 and 450 g kg,1) at each of three levels of dietary lipid (65, 90 and 115 g kg,1) accordingly. Each diet was hand fed two times daily for 8 weeks to triplicate homogenous groups of eight fish (average weight 3.34 ± 0.02 g) per tank connected to a recirculation system. Results showed that the feed efficiency and growth performance significantly (P<0.05) increased with increasing protein level at the two lower lipid levels (65 and 90 g kg,1), respectively, as indicated by indices such as %weight gain, specific growth rate, protein efficiency ratio, feed conversion ratio and feed intake, but did not at the highest lipid level (115 g kg,1). The muscle polyunsaturated fatty acids (PUFA) content declined with increasing dietary protein level at the lipid levels producing the highest growth, suggesting that the utilization of PUFA influences growth. Whereas the muscle monounsaturated fatty acids level was generally lower than the dietary levels in all the treatments tested, indicating preferential catabolism for energy, the muscle saturated fatty acids level was comparatively higher than in the diets, indicating selective deposition. Docosa hexaenoic acid (22:6n3, DHA), which was very low in the diet and in the initial fish, was higher in the muscle of some of the treatments, indicating the ability of Channa striatus to desaturate and elongate short-chain PUFA to long-chain HUFA, due to the availability of dietary 18:3n3 and 20:5n3 (the precursors for DHA biosynthesis). It could be concluded, based on the results of this trial, that a diet formulated to contain 65 g kg,1 lipid and 450 g kg,1 protein, with a gross energy of 18.5 kJ g,1 and a dietary n3/n6 PUFA ratio of about 0.1, is sufficient to promote good feed efficiency and growth performance in C. striatus fingerling. [source]

Energy and protein demands for optimal egg production including maintenance requirements of female tilapia Oreochromis niloticus

Ingrid Lupatsch
Abstract The daily requirements of a spawning tilapia female are quantified from the sum of the requirements for maintenance plus production of eggs. The protein and energy requirements for maintenance and the cost of depositing energy and protein towards growth or gonadal products were determined by supplying feed at increasing levels from zero to the maximum intake. Comparative body composition analyses of the females in addition to the amount and the content of eggs enabled us to quantify the total energy and protein channelled into weight gain or alternatively into egg production. The amount of eggs produced increased with increasing feeding levels and ranged between 0.7 and 1.1 g eggs per kg,1 fish day,1. Regardless of feed allowance, the composition of eggs was similar and contained 235 mg protein and 10.5 kJ g,1 wet weight. In contrast, the whole body of tilapia contained 167 mg protein and 6.7 kJ g,1 on average. The energy requirement for maintenance was calculated to be 59.46 kJ × BW (kg)0.80 and 0.98 g × BW (kg)0.70 for digestible protein. The partial efficiency of producing gonads was 0.67 and 0.59 for digestible energy and digestible protein respectively. [source]

Dietary non-protein energy sources: growth, digestive enzyme activities and nutrient utilization by the catfish jundiá, Rhamdia quelen

Giovanni Vitti Moro
Abstract A study was conducted to evaluate the effect of different dietary carbohydrate to lipid (CHO:L) ratios on growth, digestive enzyme activities and nutrient utilization by jundiáRhamdia quelen (Quoy & Gaimard) an omnivorous catfish native to Latin America. Groups of 40 fingerlings were stocked in 24 tanks and fed eight isonitrogenous (41% crude protein) and isoenergetic (13.5 kJ g,1) casein-based diets for 75 days. Diets had eight CHO:L ratios: 0.3:1, 1.0:1, 2.0:1, 3.4:1, 4.6:1, 5.3:1, 5.6:1 and 6.5:1, and were fed twice a day to apparent satiation. Increasing CHO:L ratio did not significantly affect growth performance. However, the highest apparent net protein utilization was observed in fish fed the 5.3:1 CHO:L diet. No differences were detected among fish on apparent net energy utilization. Whole body fat deposition decreased as dietary CHOL:L ratio increased (P<0.01). The highest fat deposition was observed in fish fed the lowest CHO:L ratio diet. Liver glycogen showed a quadratic response to the increase on dietary carbohydrate concentration, which may suggest that dietary CHO:L ratios above 3.4 can cause metabolic burden for jundiá. Therefore, despite jundiá omnivorous feeding habit, our findings indicate that dietary dextrin concentration above 15.70% (CHO:L=5.3) are not well utilized by jundiá. [source]

Optimum histidine requirement of fry African catfish, Clarias gariepinus (Burchell)

Mukhtar A Khan
Abstract Dietary histidine requirement of fry African catfish, Clarias gariepinus (2.57 ± 0.02 cm; 0.22 ± 0.03 g) was quantified by feeding casein,gelatin-based isonitrogenous (40% crude protein) and isocaloric (17.90 kJ g,1 gross energy) amino acid test diets with graded levels of histidine (0.25%, 0.30%, 0.35%, 0.40%, 0.45% and 0.50% dry diet) in eighteen 80 L indoor circular aqua-coloured troughs provided with the flow-through system for 12 weeks. Maximum absolute weight gain (2.66), best feed conversion ratio (1.29), highest protein efficiency ratio (1.94), protein retention efficiency (34%) and energy retention efficiency (70.4%) were achieved at 0.40% dietary histidine. Broken-line and non-linear regression models were adopted to assess dietary histidine requirement for C. gariepinus. When analysed using broken-line regression model these parameters were also best at 0.40% dietary histidine corresponding to 1.0% protein, respectively, whereas using second-degree polynomial regression analysis, histidine requirement was obtained at 0.42%, 0.41%, 0.40%, 0.41% and 0.41% of dry diet, corresponding to 1.05%, 1.02%, 1.0%, 1.02% and 1.02% protein respectively. Based on the broken-line and second-degree polynomial regression analyses of the growth and nutrient retention data, optimum histidine requirement of fry C. gariepinus was found to be in the range of 0.40,0.42% dry diet, corresponding to 1.0,1.05% of dietary protein. [source]

Effects of different feeding level on the growth, feed efficiency and body composition of juvenile mangrove red snapper, Lutjanus argentimaculatus (Forsskal 1775)

Ghulam Abbas
Abstract The effects of several feeding levels (1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4% and 4.5% of body weight per day, BW day,1) on the growth, feed efficiency and body composition of juvenile Lutjanus argentimaculatus (body weight 27.1 g) were examined. Fish were fed a test diet (40% protein, 18.4% lipid and 13.4 kJ g,1) for 75 days in three equal meals. Weight gain and specific growth rate increased with increasing feeding level up to 2.5% BW day,1, after which no significant improvement in growth was observed. The feed efficiency, protein efficiency ratio, retention of protein and digestibility of nutrients did not differ for fish fed 1,2.5% BW day,1, but decreased significantly when feeding levels were increased above 3% BW day,1. The chemical compositions of whole fish or body organs were significantly affected by the feeding level. The condition factor, mesenteric fat, hepato- and viscerosomatic indices were higher in fish fed 2.5,4.5% BW day,1. The cholesterol, triglycerides and haematocrit values were similar among treatments, except that high levels of plasma lipids were recorded in fish fed at 2.5% BW day,1. Taking into consideration the growth, feed efficiency and body composition data attained in this study, a feeding level of 2.5% BW day,1 is recommended for juvenile L. argentimaculatus weighing between 27 and 140 g. [source]

Effect of different oil cake sources on growth, nutrient retention and digestibility, muscle nucleic acid content, gut enzyme activities and whole-body composition in silver barb, Puntius gonionotus fingerlings

Kedar Nath Mohanta
Abstract Six iso-nitrogenous (30% crude protein) and iso-energetic (15 kJ g,1) diets were prepared using different oil cake sources, viz. groundnut, soybean, sunflower, sesame, mustard and mixed oil cakes as major ingredients, and protein sources along with a minimum of 5% fish meal in each diet and were fed to silver barb Puntius gonionotus fingerlings (16.20±0.11 g) ad libitum four times a day close to an apparent satiation level for a period of 60 days to determine the effect of diets on growth, nutrient utilization, apparent digestibility coefficient (ADC) of the nutrients in the diets, gut enzyme activity, muscle nucleic acid content and whole-body chemical composition of fish. Significantly higher (P<0.05) weight gain, specific growth rate, protein efficiency ratio, nutrient retention, ADC of nutrients in the diets, DNA:RNA ratio, protease and amylase activity with lower (P<0.05) feed:gain values were recorded in fish-fed groundnut and soybean oil cake-based diets than other diets tested. Among the dietary treatment groups, significantly higher (P<0.05) whole-body protein, lipid and energy were also found in groundnut oil cake- and soybean oil cake-based diets. The study suggests that the groundnut and soybean oil cake-based diets, which led to significantly higher (P<0.05) growth and nutrient utilization than the other oil cake-based diets in P. gonionotus fingerlings, may be used for pond culture of this species. [source]

Potential of local agricultural by-products for the rearing of African catfish Clarias gariepinus in Rwanda: effects on growth, feed utilization and body composition

Laetitia Nyina-wamwiza
Abstract This study was performed to evaluate the effect of replacing fish meal with local by-products on Clarias gariepinus growth performance, feed utilization and body composition. A control diet contained 50% of fish meal. In four other diets, fish meal was partially replaced by vegetable and animal protein blend composed of sunflower oil cake, soybean oil cake, groundnut oil cake, bean meal, chicken viscera and blood meal. The study was conducted in a recirculating water system at a mean temperature of 23.6°C. The five test diets were compared with a commercial diet developed for African catfish. All diets were balanced to be equal in gross energy (19 kJ g,1) and crude protein (40%). The experimental groups were fed in triplicate for 8 weeks, increasing fish weight from about 6.2 g at start to 52.3 g in the end. Best specific growth rate (SGR=3.4), feed efficiency (FE=1.3) and protein efficiency ratio (PER=3) were obtained with the control diet (diet 50% fish meal), although there were no significant differences between the group of fish fed the control diet and those fed diets based on groundnut oil cake or bean meal, whereas SGR (2.17), FE (0.85) and PER (1.95) were significantly (P<0.01) lower in fish fed diet containing sunflower oil cake. No significant differences (P<0.05) were found in fish fed commercial diet and diets containing bean meal or groundnut oil cake. Groundnut oil cake or bean meal can thus replace at least 50% of fish meal in the diet of Clarias fingerlings without amino acid supplementation. Because of its economic importance and its potential in animal nutrition sunflower oil cake is still an interesting feed ingredient, but its efficiency should be improved by various processing techniques. African catfish can utilize efficiently a diet with low percentage of animal protein without growth reduction. [source]

Dietary arginine requirement of fingerling hybrid Clarias (Clarias gariepinus×Clarias macrocephalus)

Shalini Singh
Abstract The dietary arginine requirement of fingerling hybrid Clarias (Clarias gariepinus×Clarias macrocephalus) (4.2±0.03 cm, 0.56±0.04 g) was determined by feeding six isonitrogenous (400 g kg,1 crude protein) and isocaloric (17.9 kJ g,1) amino acid test diets containing casein, gelatin and l -crystalline amino acids with graded levels of arginine (10.0, 12.5, 15.0, 17.5, 20.0 and 22.5 g kg,1) for 4 weeks to triplicate groups. Diets were fed twice a day at 09:00 and 16:00 hours at 8% body weight day,1. Maximum weight gain (523%), best feed conversion ratio (FCR, 1.41), protein efficiency ratio (1.78) and specific growth rate (6.53%) were recorded in fish fed the diet containing arginine at 20.0gkg,1 of the diet. Second-degree polynomial regression analysis of live weight gain and FCR values indicated the dietary arginine requirement at 17.8 and 20.0 g kg,1 of dry diet respectively. Significantly higher carcass protein and protein deposition values were recorded at the requirement level (20.0 g kg,1). Higher fat and lower moisture values were obtained in carcass of fish fed the diet with 15.0g kg,1 arginine. The maximum carcass ash value was noticed in the fish fed at 20.0 g kg,1 dietary arginine. We recommend that the diet for hybrid Clarias (C. gariepinus×C. macrocephalus) should contain arginine in the range of 17.8,20.0 g kg,1 of the dry diet, corresponding to 44.5 and 50 g kg,1 of dietary protein respectively. [source]

Effect of crude oil extracts from trout offal as a replacement for fish oil in the diets of the Australian native fish Murray cod Maccullochella peelii peelii

Giovanni M Turchini
Abstract The efficacy of trout oil (TO), extracted from trout offal from the aquaculture industry, was evaluated in juvenile Murray cod Maccullochella peelii peelii (25.4±0.81 g) diets in an experiment conducted over 60 days at 23.7±0.8 °C. Five isonitrogenous (48% protein), isolipidic (16%) and isoenergetic (21.8 kJ g,1) diets, in which the fish oil fraction was replaced in increments of 25% (0,100%), were used. The best growth and feed efficiency was observed in fish fed diets containing 50,75% TO. The relationship of specific growth rate (SGR), food conversion ratio (FCR) and protein efficiency ratio (PER) to the amount of TO in the diets was described in each case by second-order polynomial equations (P<0.05), which were: SGR=,0.44TO2+0.52TO+1.23 (r2=0.90, P<0.05); FCR=0.53TO2,0.64TO+1.21 (r2=0.95, P<0.05); and PER=,0.73TO2+0.90TO+1.54 (r2=0.90, P<0.05). Significant differences in carcass and muscle proximate compositions were noted among the different dietary treatments. Less lipid was found in muscle than in carcass. The fatty acids found in highest amounts in Murray cod, irrespective of the dietary treatment, were palmitic acid (16:0), oleic acid (18:1n-9), linoleic acid (18:2n-6) and eicosapentaenoic acid (20:5n-3). The fatty acid composition of the muscle reflected that of the diets. Both the n-6 fatty acid content and the n-3 to n-6 ratio were significantly (P<0.05) related to growth parameters, the relationships being as follows. Percentage of n-6 in diet (X) to SGR and FCR: SGR=,0.12X2+3.96X,32.51 (r2=0.96) and FCR=0.13X2,4.47X+39.39 (r2=0.98); and n-3:n-6 ratio (Z) to SGR, FCR, PER: SGR=,2.02Z2+5.01Z,1.74 (r2=0.88), FCR=2.31Z2,5.70Z+4.54 (r2=0.93) and PER=,3.12Z2,7.56Z+2.80 (r2=0.88) respectively. It is evident from this study that TO could be used effectively in Murray cod diets, and that an n-3:n-6 ratio of 1.2 results in the best growth performance in Murray cod. [source]

Potential of meat meal to replace fish meal in extruded dry diets for barramundi, Lates calcarifer (Bloch).


Abstract Juvenile barramundi (,220,280 g start weight) were fed extruded dry-pelleted diets containing varying amounts of fish meal and meat meal in three experiments (E). E1 and E2 were each 66-day farm studies utilizing 16 floating cages (400 fish per cage) in an aerated freshwater pond. E3 examined the same diets as fed in E2 but under controlled water temperature (28 ± 0.7 °C) and photoperiod (12:12) laboratory conditions in a 42-day study involving 24 aquaria (eight fish per aquarium). In all studies, the same 430 g kg,1 crude protein (CP), 15 kJ g,1 digestible energy (DE) control (Ctl) diet (containing 35% Chilean anchovy fish meal) was compared with two high-inclusion meat meal diets and a proprietary diet. The meat meal diets evaluated in E1 were a high-ash (260 g kg,1) meat meal that contained 520 g kg,1 CP and a low-ash (140 g kg,1) meat meal that contained 600 g kg,1 CP when included at either 450 or 400 g kg,1, respectively, in combination with 100 g kg,1 Chilean fish meal in diets that were isonitrogenous and isoenergetic with the Ctl diet. Growth rates and feed conversions were similar (P > 0.05) for all diets. In E2 and E3, the 520 g kg,1 CP meat meal was included at 500 g kg,1 without any marine protein source in diets formulated to provide either 15 or 16.2 kJ g,1 DE and the same CP/DE ratio (29 mg kJ,1) as the Ctl diet. Fish performance ranking of diets was similar in both experiments, with the 16.2 kJ g,1 DE diet supporting better (P < 0.05) growth rates than the Ctl diet and feed conversion ratios equivalent to the Ctl diet but better (P < 0.05) than all other diets. [source]

Nutritional evaluation of dhaincha (Sesbania aculeata) seeds as dietary protein source for tilapia Oreochromis niloticus

M A Hossain
An 8-week feeding trial was conducted in a warmwater recirculation system at 27 ± 0.2 °C to evaluate the nutritive value of dhaincha (Sesbania aculeata) seed meal as a possible fish meal substitute in the diet of tilapia. Five isonitrogenous and isoenergetic diets were formulated to contain 32% crude protein and 18.4 kJ g,1 gross energy. Sesbania seed meal was included in diets at various levels [0%, 9.7%, 19.4%, 29.1% and 38.8% for diets 1 (control), 2, 3, 4 and 5, respectively, which correspond to 0%, 10%, 20%, 30% and 40% of dietary crude protein]. Each treatment had two replicates, eight fish per replicate, with mean initial weight of 7.06 ± 0.03 g. Fish were fed 20 g kg,1 metabolic body weight daily. On the basis of the observed growth rate, feed conversion ratio, protein efficiency ratio, apparent net protein utilization and energy retention, diets 1 (control) and 2 (containing 9.7% Sesbania meal) were similar and significantly (P < 0.05) better than the other dietary groups. Fish fed diets 3, 4 and 5 containing higher levels of Sesbania meal showed significantly reduced growth performance compared with those fed diets 1 and 2. Fish fed diets 3, 4 and 5 had significantly lower faecal dry matter (DM) content, apparent crude protein, lipid and energy digestibility and reduced levels of cholesterol compared with the control and diet 2. Fish fed diets containing higher levels (>9.7%) of Sesbania meal had significantly higher whole-body moisture, lower lipid and gross energy content. The lower growth performance of fish fed diets containing higher levels of Sesbania meal is thought to result from the presence of tannins, saponin and the non-starch polysaccharide content of the seed. The results of this study showed that inclusion of up to 9.7% untreated Sesbania seed meal (10% of the dietary protein) in the diet did not affect the growth performance and nutrient utilization in tilapia. [source]