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1.
Juvenile scup, Stenotomus chrysops, 0.5–1.5 g weight were fed three different commercial diets for six weeks to determine growth rates. Diets were hand-distributed to triplicate groups of 30 fish, four times a day. Survival for all treatments was 93%. The diets used were INVE Aquaculture NRD marine diet (NRD), Skretting Feed Products Gemma starter feed (Gemma), and Salt Creek Progression fish starter diet (Progression). While all diets supported good growth, after 6 weeks scup fed the NRD diet were of significantly greater length and weight (P?<?0.05) than fish fed the other diets. The effects of each diet on fish growth were significantly different from each other (P?<?0.05), with final live weight (g), total length (mm), relative growth rate (RGR), and daily weight gain (DWG) measurements higher for fish fed the NRD diet. Scup fed the Gemma diet were of significantly greater length and weight than fish fed the Progression diet. The specific growth rate (SGR) of scup fed either the NRD or Gemma diets were not significantly different; however, both of these diets produced fish with significantly higher SGR than those fed the Progression diet. Feed conversion ratios (FCR) of scup fed either the NRD or the Gemma diets were significantly lower than the FCR of fish fed the Progression diet. SGR values were 6.6%, 6.3%?and 5.6%/day, and FCR values were 1.03, 1.11, and 1.31 for fish fed the NRD, Gemma, and Progression diets, respectively. RGR values were 1,439%, 1,212%, and 895%, and DWG values were 0.33 g, 0.27 g, and 0.20 g/day for scup fed the NRD, Gemma, and Progression diets, respectively.  相似文献   

2.
The effects of six formulated diets containing different protein and lipid levels on growth performance and body composition of juvenile southern flounder were evaluated. Test diets were prepared with a combination of three crude protein (CP) levels (45, 50 and 55%) and two crude lipid (CL) levels (10 and 15%). Diets (CP/CL) were as follows: 45/10, 45/15, 50/10, 50/15, 55/10, 55/15 and a commercial diet (50/15). Southern flounder (1.10 g) were fed the respective diets for 42 d in triplicate recirculating tanks (20 fish/tank). Percent body weight gain (BWG) for fish fed diet 45/10 (413%) and the commercial diet (426%) were significantly (P < 0.05) lower than fish fed other diets (823–837%). Increasing protein level from 45 to 50% produced a significant increase in BWG for the 10% lipid diet (823%) but further increasing protein did not produce a significant effect on BWG irrespective of dietary lipid levels. Specific growth rate (SGR), feed intake, feed conversion efficiency (FCE), protein efficiency ratio (PER), and total lipid content in the whole body were significantly affected by different dietary protein and lipid levels. Results indicated that a combination of 50% protein and 10% lipid was optimal for the growth performance of southern flounder juveniles.  相似文献   

3.
To assess the effect of dietary composition on growth performance and body composition of pike perch (Sander lucioperca), fingerlings with an initial body weight of 1.36 g (just trained to accept formulated feed) were fed three experimental diets in triplicate for 90 days. Two feeding groups were fed with formulated diets (CD, CD+7) containing varying levels of crude lipid (CL) of 14.65% and 21.94% dry matter (d.m.) with crude protein (CP) levels of 59.73% and 56.56%, and one feeding group was fed a natural diet (chironomids, CP = 65.93% d.m.; CL = 7.20% d.m.). Furthermore, pike perch of the same age caught in different natural habitats were analysed to determine their naturally fluctuations in body composition. Specific growth rate (SGR; CD = 3.36, CD+7 = 3.47) and feed conversion ratio (FCR; CD = 1.02, CD+7 = 0.93) of fish fed formulated diets did not differ significantly with rising dietary lipid content, due to high variability within the individuals of each feeding groups. In contrast, pike perch fed with chironomids showed a significantly lower SGR of 2.49 and higher FCR of 2.37 (on a dry matter basis). Body composition of pike perch fed formulated diets was affected by dietary composition and showed increased lipid contents [CD=6.25% original matter (o.m.), CD+7 = 9.00% o.m.] with rising dietary lipid levels. Pike perch of CD and CD+7 feeding groups showed significant increased hepatosomatic indices (HSIs) of 1.99 and 2.05 in contrast to fish fed chironomids with HSI of 1.11. Fish caught in the different natural habitats were characterised by low body lipid and dry matter contents of 0.64–1.88% o.m. and 21.08–23.75% o.m. Higher lipid incorporation of fish fed with formulated diets accompanied with poor benefit on growth performance at higher dietary lipid content indicated that pike perch ability to utilise lipids is low when dietary crude protein content is higher than 56.56%.  相似文献   

4.
Three feeding experiments were conducted to evaluate growth and body composition in blue caffish Ictalurus furcatus or channel caffish I. punctatus when fed diets containing 22% protein with or without supplemented methionine and/or lysine. All experiments were conducted in 110‐L aquaria that were part of a recirculating system. In Experiment 1,15 juvenile blue catfish (2.7 g) were randomly stocked into aquaria and fed one of three diets containing different (22%, 27%, and 32%) percentages of protein. Fish were fed twice daily to excess for 10 wk. In Experiment 2, juvenile blue catfish (5.4 g) were randomly stocked into aquaria and fed one of six diets containing either 22% (diet 1) or 32% (diet 2) protein. The diet containing 22% protein (diet 1) had either 0.3% crystalline L‐methionine (diet 3), 0.4% crystalline L‐lysine (diet 4), or 0.3% L‐methionine + 0.4% L‐lysine (diet 5) added. A sixth diet was formulated to contain 32% protein and 0.2% crystalline L‐methionine. Fish were fed in excess for 12 wk. In Experiment 3, juvenile channel caffish (10.3 g) were stocked and fed diets 14 from Experiment 2, twice daily in excess for 8 wk. In Experiment 1, after 10 wk, final individual weight, weight gain (%), and specific growth rate (SGR) of blue catfish fed diets containing three protein levels were not significantly different (P > 0.05) and averaged 12.9 g, 378%, and 2.2%/d, respectively. Fish fed the diet containing 27% protein had higher (P < 0.05) whole‐body protein (65.4%) compared to fish fed diets containing either 22% or 32% protein. In Experiment 2, final weight, weight gain (%) and SGR of blue catfish were not significantly (P > 0.05) different among diets and averaged 24.7 g, 355%, and 1.8%/d, respectively. Percentage whole‐body protein and lipid were not significantly (P > 0.05) different between fish fed diets containing 22% or 32% protein. In Experiment 3, channel caffish fed a diet containing 32% protein had significantly (P > 0.05) higher final individual weight, weight gain (%), and SGR compared to fish fed diets containing 22% protein, with and without supplemental methionine or lysine. Results indicate that blue catfish may be able to utilize a diet with 22% protein, and that addition of crystalline methionine and/or lysine did not improve growth. However, channel catfish grown in aquaria did not appear to have similar growth when fed a diet containing 22% protein compared to fish fed 32% protein, even when supplemental methionine or lysine was added. Further research on blue catfish and the use of a low‐protein diet (22% protein) needs to be conducted in ponds.  相似文献   

5.
Protein requirements of juvenile freshwater crayfish Cherax quadricarinatus, with initial mean weight of 1.08 ± 0.34 g, were studied. Juveniles were fed experimental diets containing seven levels of crude protein (CP) (20, 25, 31, 37, 43, 49, and 55%) and 18.73–21.45 kJ  g?1 of gross energy. The highest mean weight and specific growth rate (SGR) (P < 0.05), with values of 9.6 g, and 3.64% day?1, respectively, were achieved by feeding a diet of 31% CP. This diet resulted in a survival rate of 80% over 60 days of culture at 27 °C. The higher protein level tested (55% CP), yielded a significantly (P < 0.05) lower mean weight of 6.4 g. However, there were no significant differences in SGR among the 20, 25, and 49% CP diets. Feed Conversion Ratio (FCR) was close to 1 for all treatments except the lowest (20%) and highest (55%) CP. Optimum protein requirements were estimated by fitting mean weight gain data to a quadratic model (y = 1.142+0.484 ? 0.0071x2, r2 = 0.952, P < 0.05). Optimal growth occurred with 34.2% CP, but the results suggest that optimum protein level for 1‐g juvenile C. quadricarinatus is 31% in least‐cost diets. The information obtained will contribute to the formulation of diets that will enhance production of C. quadricarinatus.  相似文献   

6.
An 8‐wk feeding trial was conducted to estimate the optimum dietary protein level and protein‐to‐energy (P/E) ratio in juvenile parrot fish, Oplegnathus fasciatus. Eight experimental diets were formulated with two energy levels and four protein levels for each energy level. Diets containing crude protein (CP) at 35, 40, 45, and 50% had either 12.5 or 14.6 kJ/g of energy. Fish averaging 7.1 ± 0.06 g (mean ± SD) were fed one of the experimental diets for 8 wk. At the end of the feeding trial, weight gain (WG) of fish fed 45 and 50% CP in the 12.5 kJ/g diet was significantly higher than fish fed the 35% CP diet (P < 0.05). WG of the fish fed 45 and 50% CP in the 14.6 kJ/g diet was significantly higher than fish fed the 35 and 40% CP diets (P < 0.05). Fish fed the 14.6 kJ/g diet had a higher WG compared with fish fed the 12.5 kJ/g diet at all CP levels. Feed efficiency (FE) and specific growth rate (SGR) showed a similar trend to the WG. WG, FE, and SGR improved with increasing dietary protein levels up to 45% and remained constant at 50% CP for both energy levels. However, protein efficiency ratio was negatively related to dietary protein levels. The results suggested that the optimum level of protein and the optimum P/E ratio for juvenile parrot fish should be 45% and 31.1 mg protein/kJ, respectively, in a diet containing 14.6 kJ/g energy.  相似文献   

7.
This study was conducted to evaluate the effects of dietary protein on digestive enzyme profiles, growth and tail muscle composition in the freshwater redclaw crayfish, Cherax quadricarinatus. Crayfish were fed five diets that consisted of a commercial crayfish pellet and experimental diets containing 13%, 18%, 25% or 32% crude protein (CP), for a period of 12 weeks. Analysis of digestive enzyme profiles from the midgut gland (MG) revealed a positive correlation between protease, amylase and cellulase activities and dietary protein level. For all treatments, carbohydrase activity levels (cellulase and amylase) were significantly higher than those detected for protease. As dietary protein was elevated, there was a general increase in specific growth rate (SGR), with the highest SGR (0.58 ± 0.06) values observed in crayfish fed the diet containing 25% CP. Feed conversion ratio (FCR) ranged between 5.84 and 6.97 and did not differ significantly among the treatment groups including the reference diet, with the exception of the low‐protein diet (13% CP) which showed an FCR of 9.31. Finally, regression analysis revealed a strong positive correlation between the level of dietary protein and CP content in the tail muscle (P=0.004; r2=0.99).  相似文献   

8.
A 63‐day growth trial was undertaken to estimate the effects of supplemented lysine and methionine with different dietary protein levels on growth performance and feed utilization in Grass Carp (Ctenopharyngodon idella). Six plant‐based practical diets were prepared, and 32CP, 30CP and 28CP diets were formulated to contain 320 g kg?1, 300 g kg?1 and 280 g kg?1 crude protein without lysine and methionine supplementation. In the supplementary group, lysine and methionine were added to formulate 32AA, 30AA and 28AA diets with 320 g kg?1, 300 g kg?1 and 280 g kg?1 dietary crude protein, respectively, according to the whole body amino acid composition of Grass Carp. In the groups without lysine and methionine supplementation, weight gain (WG, %) and specific growth rate (SGR, % day?1) of the fish fed 32CP diet were significantly higher than that of fish fed 30CP and 28CP diets, but no significant differences were found between 30CP‐ and 28CP‐diet treatments. WG and SGR of the fish fed 32AA and 30AA diets were significantly higher than that of fish fed 28AA diets, and the performance of grass carp was also significantly improved when fed diets with lysine and methionine supplementation (P < 0.05), and the interaction between dietary protein level and amino acid supplementation was noted between WG and SGR (P < 0.05). Feed intake (FI) was significantly increased with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05), but feed conversion ratio (FCR) showed a significant decreasing trend (P < 0.05). Two days after total ammonia nitrogen (TAN) concentration test, the values of TAN discharged by the fish 8 h after feeding were 207.1, 187.5, 170.6, 157.3, 141.3 and 128.9 mg kg?1 body weight for fish fed 32CP, 32AA, 30CP, 30AA, 28CP and 28AA diets, respectively. TAN excretion by grass carp was reduced in plant‐based practical diets with the increase in dietary protein level and the supplementation of lysine and methionine (P < 0.05). The results indicated that lysine and methionine supplementation to the plant protein sources‐based practical diets can improve growth performance and feed utilization of grass carp, and the dietary crude protein can be reduced from 320 g kg?1 to 300 g kg?1 through balancing amino acids profile. The positive effect was not observed at 280 g kg?1 crude protein level.  相似文献   

9.
A growth trial was conducted to examine the effect of dietary digestible energy (DE) content on methionine (Met) utilization and requirement in juvenile Nile tilapia (Oreochromis niloticus). Ten iso‐nitrogenous (288 g kg?1 protein) practical diets, with two DE levels (10.9 MJ kg?1; 12.4 MJ kg?1) and five methionine supplementation levels (0, 1, 2, 4 and 6 g kg?1), were hand‐fed twice daily to triplicate groups of Nile tilapia (initial body weight 8.95 ± 0.06 g) for 8 weeks. Weight gain (WG) and specific growth rate (SGR) increased significantly with increasing dietary methionine concentration at the same DE content (P < 0.001). At the same dietary methionine level, WG and SGR of fish fed high‐DE diets were significantly higher than that of fish fed low‐DE diets (P = 0.0001), although no interaction was found between dietary DE and methionine supplementation. Based on quadratic regression analysis between dietary methionine concentration and weight gain, optimal methionine requirement for maximum growth, expressed as g Met required kg?1 diet (low‐ versus high‐DE diets), increased as diet DE concentration increased (7.34 versus 9.90 g kg?1 diet, respectively; with cysteine 4.70 g kg?1 diet). The results indicated that diet DE content affects methionine utilization and requirement in juvenile Nile tilapia, fish fed high‐DE diets required more methionine for maximum growth.  相似文献   

10.
A feeding trial was carried out where five protein concentrations [26%, 29%, 33%, 37%, and 41% crude protein (CP)] were fed to jundia fingerlings at two dietary energy concentrations [3200 and 3650 kcal metabolizable energy (ME)/kg diet] to establish the protein requirement for this species. Triplicate groups of 23 fish (average weight 1.52±0.34 g) were each stocked in 120-l aquaria and fed semipurified diets twice a day to apparent satiation. After 90 days, fish weight gain (WG), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), energy retention (ER), apparent net protein utilization (ANPU), feed consumption (% body weight) and body composition (crude protein, fat, and ash) were affected by diet composition. Weight gain, SGR, FE, ANPU and ER increased (P<0.05) as the dietary protein concentration increased up to 33% and 37%, for fish fed diets containing 3650 and 3200 kcal, respectively. A significant interaction between dietary protein and energy was observed for WG, SGR, and PER. Feed consumption was not affected by dietary energy concentration, but decreased with increasing dietary protein concentration (P<0.05). Body fat decreased as dietary protein increased at both energy concentrations, but was higher in fish fed the 3650 kcal diet. The opposite was observed for body protein, ER, and ANPU (P<0.05). Our findings demonstrate that jundia presents dietary protein sparing effect when the energy concentration increases from 3200 to 3650 kcal/kg. Jundia protein requirement, determined by the broken line method, is between 32.6% and 37.3% CP, depending on dietary energy concentration.  相似文献   

11.
A feeding trial was conducted in aquaria with juvenile hybrid tilapia (Oreochromis niloticus×Oreochromis aureus) to evaluate the use of different protein sources in combination with distillers dried grains with solubles (DDGS). Twelve 110‐L glass aquaria were stocked with 28 juvenile (2.7±0.5‐g) hybrid tilapia per aquarium. Three replicate aquaria were randomly assigned to each of the four dietary treatments. Diets were isonitrogenous and isocaloric. The control diet contained 12% fish meal and 41% soybean meal as the primary protein sources (Diet 1). Each experimental diet contained 30% DDGS by weight, in combination with 8% fish meal and 34% soybean meal (Diet 2), 26% meat and bone meal (MBM), and 16% soybean meal (Diet 3), or 46% soybean meal alone (Diet 4). Fish were fed to apparent satiation twice a day for 10 weeks. There were no significant differences (P>0.05) in average weight gain, specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER) among tilapia fed Diets 1, 2, and 3. Fish fed Diet 4 had significantly lower (P<0.05) average weight gain, SGR, and PER than fish fed Diets 1 and 3. Relative cost per unit weight gain for Diets 1, 2, and 3 were statistically similar (P>0.05), while cost per unit weight gain for Diet 4 was significantly higher (P<0.05) than other diets. Diet 3 represented approximately a 20% cost savings compared with the control diet, with no reduction in growth. This study indicates that diets without fish meal containing 30% DDGS in combination with MBM and soybean meal provide good growth in tilapia. A diet without animal protein did not support acceptable growth.  相似文献   

12.
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.  相似文献   

13.
The present study was designed to determine the optimal dietary lysine requirement for jundiá, Rhamdia quelen, fingerlings. Groups of 17 fish (1.4 ± 0.1 g) were stocked in 120‐L tanks and were fed semipurified diets (33% crude protein [CP] and 3500 kcal metabolizable energy) containing increasing concentrations of lysine (3.0, 4.0, 4.5, 5.0, 5.5, 6.0, and 6.5% CP). After 119 d, fish weight gain (WG), specific growth rate (SGR), feed intake and feed conversion (FC), apparent net protein utilization (ANPU), body composition (CP, fat, and ash), and vertebral collagen were determined. WG and SGR increased as dietary lysine concentration in protein increased up to 4.5%, reducing at 6.0 and 6.5% lysine. Fish that were fed the lowest lysine concentration presented the worst feed conversion (FC), which improved for fish fed with 4.5% or more lysine. Feed consumption followed the same trend as FC. The highest ANPU was observed in fish fed with 4.5% lysine. Fish fed diets containing 4.5, 5.0, and 5.5% lysine accumulated more body protein (P < 0.05). Collagen vertebral concentration was significantly higher in fish fed with the 4.5% lysine diet. Dietary requirement for lysine was 4.5 or 5.1% depending on the statistical model used for estimation: broken line or polynomial regression, respectively. The requirements for the other essential amino acids were estimated on the basis of the ideal protein concept and were similar to the requirements for other fish species, except for isoleucine, leucine, treonine, and valine, which were higher for jundiá.  相似文献   

14.
The influence of soybean meal (SBM) on the growth and feed utilization of juvenile sutchi catfish (Pangasianodon hypophthalmus, Sauvage, 1878) was investigated. Eight isonitrogenous (300 g kg?1 CP) and isoenergetic (18 MJ kg?1) diets were formulated incorporating Argentine SBM to replace fish meal at 0, 150, 300, 450, 600, 750, 900 and 1000 g kg?1 dietary protein. Each diet was fed to three replicate groups of fish with an initial weight 6.0–6.2 g for twelve weeks. Growth performance decreased, and feed utilization was worsened with the increase in SBM inclusion in the diets. Final weight and relative growth rate (RGR) of fish fed control diet (0 SBM) were significantly higher than those fed test diets (P < 0.05). However, there were no significant differences in the final weight and RGR between the fish fed on 15 SBM, 30 SBM, 45 SBM and 60 SBM diets. Specific growth rate of fish fed 0 SBM, 15 SBM, 30 SBM and 45 SBM diets was significantly higher than those fed other diets. Feed conversion ratio of fish fed 0 SBM, 15 SBM, 30 SBM, 45 SBM and 60 SBM diets was significantly lower than those fed other diets (P < 0.05). The dry matter and protein digestibility were lesser in all the diets in comparison with the control diet. Hepatosomatic index and viscerosomatic index increased with increasing SBM in diet. This present trial indicated that fish meal can be replaced by SBM in the diet of juvenile sutchi catfish only up to 45% of fish meal protein without any adverse effect on growth, feed utilization and body composition.  相似文献   

15.
The main objectives of this study were to evaluate the effect of partial and total replacement of fish meal (FM) protein by cow pea seed meal (CPSM) protein in practical diets on growth performance, feed utilization, and body composition of Nile tilapia, Oreochromis niloticus (L.). Fish of an average initial weight of 4.6 ± 0.2 g were stocked in 15 glass aquariums (80 L each) at a rate of 15 fish per aquarium. FM protein (30% of the diet) was used as the sole source of animal protein in the control diet. Percent replacement of FM by CPSM on the basis of crude protein were as follows: 0% (control diet A), 25% (diet B), 50% (diet C), 75% (diet D), and 100% (diet E). Diets were fed to fish at a rate of 4% of the total fish biomass daily, for a period of 16 wk. The results of this study revealed that the fish fed control diet A (100% FM) had the best average final body weight, specific growth rate (SGR %/d), weight gain (g/fish), weight gain %, while the poorest results for all parameters were obtained with fish fed diet E (100% CPSM). The same parameters of fish fed diets B (25% CPSM) and C (50% CPSM) were not significantly different (P > 0.05) from those of fish fed the control diet A. Feed utilization parameters of fish fed diets A, B, C, and D were better than for diet E. Proximate composition of whole‐body moisture and ash contents were not significantly different (P > 0.05) among all experimental diets and control diet. Whole‐body protein contents for fish fed diets B and C were superior to the control diet A. Incorporation of CPSM in the diets significantly increased whole‐body fat content. Incorporation of CPSM in the diets significantly decreased apparent digestibility coefficient of crude protein crude fat and energy. Diets B and C were not significantly different from control diet A. Therefore, these findings suggest that up to 50% of FM protein can be replaced by CPSM protein in Nile tilapia diets without any adverse effects on growth performance, feed utilization, body composition, and digestibility.  相似文献   

16.
Effects of dietary inclusion of yacon, Polymnia sonchifolia (YC), ginger, Zingiber officinale (GG), and blueberry, Vaccinium ashei (BB), on growth, body composition and challenge test of rockfish against Edwardsiella tarda compared to ethoxyquin were investigated. Three hundred and sixty fish were randomly distributed into 12 flow‐through tanks. Four experimental diets were prepared: the control diet (Con) with 0.1 g/kg ethoxyquin, and YC, GG and BB diets. Each diet was assigned to triplicate tanks of fish and hand‐fed for 8 weeks. Externally normal fish after fourth and eighth weeks of feeding trial were infected with Edwardsiella tarda for challenge test. Weight gain and specific growth rate (SGR) of fish fed the YC diet were greater than those of fish fed all other diets. Feed efficiency, protein efficiency ratio and protein retention of fish fed the YC diet were higher than those of fish fed all other diets. In the both fourth and eighth weeks of infection trials, mortality of fish fed the Con diet was higher than that of fish fed all other diets. In conclusion, dietary inclusion of YC, GG and BB increased weight gain and SGR of fish. YC, GG and BB for 4 and 8 weeks lowered mortality of fish at occurrence of E. tarda.  相似文献   

17.
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.  相似文献   

18.
A feeding trial was conducted to investigate the effects of dietary graded protein levels on the growth, survival, amylase and trypsin activities of large yellow croaker (Pseudosciaena crocea R.) larvae from 12 to 42 days after hatching (DAH). Five approximately isoenergetic microbound diets (16.65 MJ/kg diet) were formulated to contain different protein (47.1%, 52.0%, 57.1%, 62.2% and 67.5%) levels. Frozen copepods, containing 54.5% crude protein (CP), 6.0% crude lipid, 27.2% ash and 6.7% glycogen, were used as a control. Each diet was randomly fed to triplicate groups of larvae with an initial mean body weight of 1.76 ± 0.09 mg (mean ± SD) in 180 L white plastic tanks, and each tank was stocked initially with 3500 larvae. Both the survival and the specific growth rate (SGR) of large yellow croaker larvae significantly increased with increasing dietary protein level up to 57.1%, and decreased thereafter. Frozen copepods resulted in intermediate survival and low SGR compared with the other diets. Whole‐body moisture and protein of larvae were not significantly affected by the dietary protein level. In contrast, whole‐body lipid of larvae fed diet with 47.1% CP was significantly higher (P<0.05) than those from fish fed the diets containing more than 57.1% CP. Additionally, fish fed the frozen copepods had the lowest whole‐body protein and lipid. The amylase‐specific activity increased with increasing dietary carbohydrate level during the period of this experiment. However, trypsin activity was not significantly affected by the dietary protein content before 42 DAH, indicating a later onset of trypsin than amylase in the regulation of enzymatic synthesis induced by a dietary substrate.  相似文献   

19.
An 8-wk feeding trial was conducted to estimate the optimum dietary protein level and protein-to-energy (P/E) ratio in juvenile Korean rockfish Sebastes schlegeli. Twenty experimental diets were formulated with four energy levels and five protein levels at each energy level. Four gross energy levels of 14.2, 16.5, 18.6, and 20.9 kJ/g diet were included at various crude protein (CP) levels. Diets containing CP at 30, 40, 45, 50, and 55% had either 14.2 or 16.5 kJ/g energy; those with CP levels of 35, 40, 45, 50, and 60% had either 18.6 or 20.9 kJ/ g energy. After 2 wk of conditioning, fish initially averaging 7.3 ± 0.04 g (means ± SD) were randomly distributed into net cages as groups of 20 fish. Each diet was fed to fish in three randomly selected net cages for 8 wk. After 8 wk of the feeding trial, weight gain (WG) of fish fed 50% and 55% CP with 14.2 kJ/g diet was significantly higher than those of fish fed 30% and 40% CP diets (P 0.05). WG of fish fed 45, 50, and 55% CP with 16.5 kJ/g diet was significantly higher than those of fish fed 30% and 40% CP diets (P < 0.05). WG of fish fed 60% CP with 18.6 kJ/g diet was significantly higher than those of fish fed 35, 40, and 45% CP diets. WG of fish fed 45% CP with 20.9 kJ/g diet was significantly higher than those of fish fed 35, 40, and 60% CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, protein efficiency ratio (PER) was negatively related to dietary protein levels. WG of fish did not always increase with increasing dietary protein and energy levels. Comprehensive comparison among diets containing 40, 45, and 50% CP with different energy levels indicated that the increase in protein from 40 to 45% significantly increased WG (P < 0.05), but such effect was not significant when protein increased from 45 to 50% at all energy levels. Increasing dietary energy significantly increased WG of fish fed 40% and 45% CP at each energy level; however, there was no difference in WG of fish fed 50% CP with energy levels of 18.6 and 2.9 kJ/g diet. There was no significant difference in WG of fish fed 50% CP with 18.6 kJ/g or 45 and 50% CP with 20.9 kJ/g diet. Broken-line analysis of weight gain indicated that the optimum dietary protein level was 50.9 ± 1.1% and PIE ratio was 35.4 ± 0.8 mg/kJ with 14.2 kJ/g diet; the optimum dietary protein level was 49.3 ± 5.0% and P/E ratio was 30.2 ± 1.0 mg/kJ with 16.5 kJ/g diet; the optimum dietary protein level was 46.2 ± 9.2% and P/E ratio was 24.7 ± 4.9 mg/kJ with 18.6 kJ/g diet; and the optimum dietary protein level was 45.1 ± 1.8% and P/E ratio was 21.5 ±0.7 with 20.9 kJ/g diet. Therefore, these data indicated that the concept of P/E ratio must be restricted to diets containing adequate protein and energy levels. Based on WG, the optimum P/E ratio was between 21.5 and 35.4 mg protein/kJ gross energy in juvenile Korean rockfish when gross energy ranged from 14.2 to 20.9 kJ/g diet.  相似文献   

20.
A 10‐wk feeding trial was conducted to estimate the dietary protein requirements of juvenile Dianchi golden‐line barbell, Sinocyclocheilus grahami (initial average weight 7.55 g). Five isocaloric diets were formulated to contain graded levels of protein (29, 34, 39, 44, and 49%). Each diet was fed to triplicate groups of fish in a recirculating rearing system maintained at 18–22 C. Feed intake of fish fed the diet with 39% protein was significantly higher than those fed the diet with 29, 34, and 49% protein (P < 0.05). Weight gain, specific growth rate (SGR), and protein gain significantly increased with increasing dietary protein levels up to 39% (P < 0.05), whereas no significant differences were observed among fish fed the diet with 39, 44, and 49% protein (P > 0.05). In contrast, feed conversion ratio was significantly decreased with increasing dietary protein levels up to 39%. Maximum protein retention and protein efficiency ratio were observed in fish fed the diet with 39% protein. The regression analysis based on SGR and protein gain showed that the dietary protein requirements of juvenile S. grahami were 38.57% or 41.09% (equivalent to ca. 32.94% or 35.42% estimated digestible protein) of diet with a calculated digestible energy of 3.6 kcal/g.  相似文献   

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