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1.
Nutrient apparent digestibility coefficients (ADCs) of pet food grade poultry by‐product meal (PBM) were determined for black tiger prawn, Penaeus monodon and Pacific white shrimp, Litopenaeus vannamei by the indirect method (reference diet and test diet at 7:3 ratio). Subsequently, an 8‐week growth trial was conducted to evaluate the effects of substitution of fishmeal (FM) with PBM in diets of P. monodon (initial weight = 0.21 ± 0.01 g). In the growth trial, six isonitrogenous and isoenergetic diets PBM0, PBM25, PBM50, PBM75, PBM100 and PBMA100, containing a gradient of PBM 0, 88.7, 177.4, 266, 354.7 and 354 g kg?1 to replace 0, 92.5, 185, 277.5, 370 and 370 g kg?1 FM were fed to four replicate groups respectively. The diet PBMA100 was supplemented with DL‐Met to be similar to PBM0. The results showed that both P. monodon and L. vannamei had relatively high ADC of crude protein (77.6% and 84.2% respectively) and gross energy (72.8% and 84.0% respectively) for PBM. Litopenaeus vannamei showed significantly higher digestion ability for PBM than P. monodon (P < 0.05). In growth trial, no significant difference in growth performance was observed among shrimp fed the experimental diets. DL‐Met supplementation did not improve the growth of P. monodon. PBM is a suitable protein ingredient for P. monodon feeds and can be used up to 354.7 g kg?1 to totally replaced FM.  相似文献   

2.
Six isonitrogenous (320 g kg?1) and isolipidic (60 g kg?1) diets were formulated with graded levels (0, 5, 10 and 15 g kg?1) of dicalcium phosphate (DCP) and fungal phytase (750 and 1500 FTU kg?1 diet). Tra catfish (Pangasianodon hypophthalmus), 9.6 g, were fed the diets for 12 weeks. Each experimental diet was fed to eight replicates of fish to apparent satiation. At the end of the trial, fish fed the diets containing 15 g kg?1 DCP, 750 and 1500 FTU kg?1 phytase had higher growth performances, protein efficiency ratio and phosphorus retention than those fed the control diet, 5 g kg?1 DCP and 10 g kg?1 DCP diets (P < 0.05). Whole body ash and phosphorus concentration of fish fed the 10 g kg?1 DCP and 15 g kg?1 DCP diets were significantly higher than those of fish fed the control diet. Higher apparent digestibility coefficient of phosphorus was observed in fish fed the phytase supplemented diets. The present results indicate that supplementation of phytase at 750 FTU kg?1 and 1500 FTU kg?1 improves growth performances, feed and phosphorus utilization. The supplementation can completely replace dicalcium phosphate or other phosphorus sources in tra catfish feed and reduce the phosphorus discharge into environment.  相似文献   

3.
Growth and digestibility trials were conducted to evaluate the use of flash dried yeast (FDY) as a supplement in practical shrimp feeds. The six‐week growth trial evaluated the effects of FDY supplementation (0, 10, 20, 40 and 60 g kg–1) in the plant‐based practical diet on the performances and proximate compositions of juvenile Pacific white shrimp, Litopenaeus vannamei. Final biomass, final mean weight, per cent weight gain (WG), feed conversion (FCR) and protein retention efficiency (PRE) of Pacific white shrimp were not significantly influenced when FDY was added up to 40 g kg–1 of the diet. However, 60 g kg–1 FDY supplementation significantly reduced growth, feed utilization and protein retention. Supplementation of FDY in the practical diets of Pacific white shrimp did not affect protein, moisture, lipid, crude fibre, and ash content of whole shrimp body. Apparent digestibility coefficients of energy, protein, and amino acid (AA) for FDY were determined using chromic oxide as an inert marker and the 70:30 replacement technique. The energy and protein digestibility of FDY were 38.20% and 53.47%, respectively, which were significantly lower than fishmeal (FM) and soybean meal (SBM) that were run at the same time. Most amino acid digestibility of FDY was lowest among the three ingredients tested. Results of this work indicated that energy, protein and amino acid digestibility of FDY are lower compared to SBM and FM, and high levels supplementation (≥60 g kg–1) of FDY can cause negative effects to the growth response of Pacific white shrimp. Based on these results, further research regarding the effects of the low level inclusion of FDY in practical diets on immune responses of Pacific white shrimp is warranted.  相似文献   

4.
Two digestibility trials and two growth trials were carried out to evaluate the influence of top‐sprayed phytase on apparent digestibility coefficients (ADCs) of protein and mineral and utilization in rainbow trout fed with soybean meal‐based diets. In Trial 1, a semi‐purified diet containing 50% soybean meal was supplemented with graded levels of phytase (0, 500, 1000, 2000 and 4000 U kg?1 diet), and fed to triplicate groups of fish. In Trial 2, commercial‐type extruded feeds containing 36% soybean meal with either 0 or 2000 U phytase kg?1 were fed to five replicate groups of fish. Phytase clearly decreased phytic acid content of feces from 35 to 5 mg and from 34 to 14 mg phytic acid per g faecal dry matter in Trials 1 and 2 respectively. Apparent digestibility coefficient of P improved from 23% to 83% in Trial 1 and from 35% to 54% in Trial 2 by phytase. Apparent protein increased by 1.2% and 3.2%‐units by phytase in Trials 1 and 2. Zinc digestibility was significantly increased in Trial 1, but not in Trial 2. Trials 3 and 4 were conducted to evaluate the influence of phytase on dietary P (Trial 3) and lysine (Trial 4) utilization. Three diets were prepared for each trial: P (Trial 3)‐ or lysine (Trial 4)‐deficient basal diets, basal diets with phytase supplementation (2000 U kg?1) and P (Trial 3)‐ or lysine (Trial 4)‐fortified diets. Rainbow trout (initial weight 20 g) were fed for 10 weeks using four and six replicates for Trials 3 and 4 respectively. Phytase increased P utilization in Trial 3 as demonstrated by an increase in vertebra ash from 24.1% to 45.4%, and by an increase in weight gain from 243% to 459% of the initial weight. Phytase did not increase lysine utilization, since neither protein retention nor weight gain were enhanced by phytase. Supplemental lysine increased protein retention and weight gain to 43.1% and 514%, respectively, and also decreased whole‐body lipid contents significantly from 120 to 123 g kg?1 in fish fed the basal diet and phytase‐supplemented diet to 106 g kg?1 in fish fed with lysine‐fortified diet.  相似文献   

5.
An 8‐week feeding trial was conducted to evaluate the optimum dietary γ‐aminobutyric acid (GABA) level in low fishmeal diet for juvenile Pacific white shrimp, Litopenaeus vannamei. Six practical diets (449 g kg?1 protein, 87 g kg?1 lipid) supplemented with graded levels of GABA (0, 50, 100, 150, 200, 250 mg kg?1) were formulated. Each diet was randomly assigned to triplicate groups of 30 shrimps (approximately 0.44 g), and the shrimps were fed four times a day to apparent satiation. Weight gain and gain rate were significantly increased with the supplementation of GABA (P < 0.05). Hepatosomatic index and survival were also significantly influenced by the dietary GABA levels (P < 0.05) and show a similar trend to those of growth performance. Insulin and neuropeptide Y concentrations in blood were increased with the supplementation of GABA. In total, 150 mg GABA kg?1‐supplemented diets significantly increased the survival after 12, 24 and 36 h of NH3 stress, also increased the total antioxidant capacity, total superoxide dismutase, catalase, antihydroxyl radical and phenoloxidase activities before and after the 36 h NH3 stress compared to basic group. These results clearly indicated that GABA could improve growth performance, antioxidative capacity and resistance against NH3 stress in L. vannamei, and 150 mg kg?1 GABA supplementation was suitable for L. vannamei fed with low fishmeal diet.  相似文献   

6.
One experiment was conducted to determine the nutritive value of phospholipids on growth performance of early postlarval shrimp, Litopenaeus vannamei. Five isoenergic and isonitrogenous diets with five supplemented levels of phospholipids (P1, P2, P3, P4 and P5 with 0, 10, 20, 40 and 80 g kg?1 diet, respectively) were fed to triplicate groups of L. vannamei (mean initial wet weight 0.8 mg) for 27 days. After the 27‐day feeding trial, the lowest weight gain (WG, %) and specific growth rate (SGR, % day?1) was found in P1 treatment, the highest WG and SGR was found in P3, P4 and P5 treatments, P2 treatment provided intermediate result and showed significant difference compared to P1, P3, P4 and P5 treatments. Shrimp fed the P1 diet had significantly lower survival than shrimp fed other diets, while no significant difference was found in survival among P2, P3, P4 and P5 treatments. Broken‐line analysis on WG indicated that the optimum dietary phospholipids for early postlarval shrimp, L. vannamei, is 45.96 g kg?1 diet.  相似文献   

7.
Two trials were conducted to evaluate the performance of Pacific white shrimp Litopenaeus vannamei offered diets containing various copper (Cu) levels from Cu hydroxychloride (Cu2(OH)3Cl) containing 58.81% copper in the clear water recirculating system. In both trials, the basal diet (360 g kg?1 protein, 80 g kg?1 lipid) containing approximately 10 mg Cu kg?1 was primarily comprised of fishmeal, soybean meal, corn protein concentrate and whole wheat. In trial 1, test diets were produced supplementing the basal diet with 5, 10, 20, 40 and 60 mg Cu kg?1 from Cu hydroxychloride. Four replicate groups of 15 shrimp per tank (initial weight 0.28 g) were offered diets in slight excess over 8 weeks. In trial 2, the basal diet was supplemented with 30, 90, 150, 210 and 270 mg Cu kg?1 from Cu hydroxychloride. Seven replicate groups of 15 shrimp per tank (initial weight 0.22 g) were offered feed in slight excess over 7 weeks. At the end of the two growth trials, no significant differences were observed in final biomass, final mean weight, percentage weight gain, feed conversion ratio (FCR) and survival. In trial 1, the Cu concentrations of the carapace, hepatopancreas and whole shrimp linearly increased with increasing dietary Cu supplements. In trial 2, polynomial regression of Cu concentrations of the carapace, hepatopancreas and whole shrimp against analysed dietary Cu content indicated that a plateau was reached at 215 mg analysed Cu kg?1. Results of this study indicate that there was no negative effect of high levels of Cu supplement with regard to growth and survival. Tissue levels generally increased up to around 200 mg Cu kg?1 diet and then decreased, possibly indicating a shift in physiology.  相似文献   

8.
This work evaluated the performance of Litopenaeus vannamei to low fish meal diets supplemented with 2‐hydroxy‐4‐(methylthio)butanoic acid (HMTBa). A basal diet with 150.0 g kg?1 of anchovy fish meal was designed. Two positive control diets were formulated to reduce fish meal at 50% and 100% with 1.0 and 2.0 g kg?1 of MERA? MetCa (calcium salt with 84% HMTBa activity), respectively. Two nearly equivalent diets acted as negative controls, without HMTBa supplementation. A total of 50 clear‐water tanks of 500 L were stocked with 2.22 ± 0.19 g shrimp under 70 animals m?2. Shrimp survival (92.3 ± 5.1% and 81.4 ± 8.0%), yield (808 ± 12 and 946 ± 17 g m?2) and FCR (2.17 ± 0.19 and 3.12 ± 0.37) showed no differences among diets after 72 or 96 days, respectively. A significantly higher shrimp body weight and weekly growth were observed for those fed with the basal diet or diets supplemented with HMTBa compared with non‐supplemented ones. This study has shown that L. vannamei growth, body weight, survival, yield and FCR were supported by HMTBa supplementation when 150.0 g kg?1 of fish meal was replaced by soybean meal and other ingredients, at 50% and 100%.  相似文献   

9.
A feeding trial was conducted for 60 days to study the effects of exogenous microbial phytase supplementation on the growth and nutrient digestibility of Pangasius pangasius fingerlings. Eight isocaloric and isoprotein experimental diets (35.67% crude protein and 3870 kcal kg?1) were prepared with graded levels of phytase, e.g., 0 (T1), 150 (T2), 250 (T3), 350 (T4), 500 (T5), 1000 (T6) and 2000 (T7) FTU (phytase units) kg?1. Three hundred and fifteen fingerlings of P. pangasius (1.97–2.05 g) were randomly distributed in seven treatments with three replicates each. Maximum weight gain (350.72%), specific growth rate (2.51%), protein efficiency ratio (2.1), apparent net protein utilization (27.85%), energy retention value (88.47%) and feed conversion efficiency were observed in T5 group supplemented with 500 FTU phytase kg?1 diet. Apparent dry matter and protein digestibility in phytase‐supplemented groups were significantly (P<0.01) higher at a minimum supplement of 500 FTU kg?1 or higher. Liver alkaline phosphatase activity increased significantly in treatment groups. Supplementation at 500 FTU kg?1 of phytase is optimum in the diet of P. pangasius fingerlings.  相似文献   

10.
Three growth trials and a digestibility trial were designed to evaluate the efficacy of a novel bacterial biomass (BB) in commercial‐type feed formulation for Pacific white shrimp, Litopenaeus vannamei. In trial 1, the basal diet was supplemented with 0, 60 and 120 g/kg BB to replace soybean meal (SBM). Significant improvement was observed in the survival when BB was incorporated in the diets. However, shrimp fed diets containing 120 g/kg BB exhibited significantly lower weight gain (WG) and higher feed conversion ratio (FCR). To confirm the results from trial 1 and explore the effects of BB supplementation at low levels, the basal diet was incorporated with 0, 10, 20, 40, 60 and 120 g/kg BB to replace SBM in trial 2. Significant reductions in WG, FCR, lipid content of whole body, protein retention efficiency and most amino acids retention efficiency were detected in shrimp fed with diet containing 120 g/kg BB. Trial 3 was designed to elucidate whether the digestible protein is the cause of reduced growth. No improvements in terms of growth performance and FCR were detected in the treatments balanced for digestible protein. Apparent digestibility coefficients of energy, protein and amino acid (AA) for BB were determined using chromic oxide as an inert marker and the 70:30 replacement technique. The energy, protein and individual amino acid digestibility coefficients of BB were significantly lower than those of fish meal (FM) and SBM that were given at the same time. Results of this study indicated that BB can be utilized up to 40 g/kg in shrimp feed without causing a decrease in growth. However, supplementations (≥60 g/kg) of BB can result in negative effects on growth response, FCR and protein as well as amino acids retention efficiency. At the lower levels of inclusion, shrimp performance was improved when BB was supplemented on a digestibility basis; however, at the higher level of inclusion, there was no improvement, indicating there may be other nutrients limiting. Based on enhanced survival in the treatment with BB supplementation in trial 1, further research regarding the immune effects of BB in practical shrimp feed will be necessary.  相似文献   

11.
The effect of chitosan, a polymer of glucosamine obtained by the deacetylation of chitin, on growth, survival and stress tolerance was studied in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed five isoenergic and isonitrogenous diets containing five supplemented levels of chitosan (0, 0.5, 1, 2 and 4 g kg?1 diet, respectively). The five compound diets (C0, C0.5, C1, C2 and C4) sustained shrimp growth throughout the experiment. Growth performance (final body weights; weight gain; SGR: specific growth rate) in shrimp fed diet C2 was significantly higher than that in shrimp fed diets C0, C0.5 and C1 (P < 0.05), diet C4 treatment provided intermediate growth result. The survival in shrimp fed diet C1 was significantly higher than that in shrimp fed C0 diet (P < 0.05), other diets treatments gave the intermediate survival results. No significant differences were found in growth and survival between diet C2 and C4 treatments. After 9 days of a stress tolerance test, survival in shrimp fed diets C1, C2 and C4 was significantly higher than that in shrimp fed diets C0 and C0.5. We concluded from this experiment that the incorporation of a moderate dietary chitosan was beneficial to the development of postlarval L. vannamei. Considering the effect of chitosan on both growth and survival of postlarval L. vannamei, second‐degree polynomial regression of SGR and survival indicated optimum supplement of dietary chitosan at 2.67 and 2.13 g kg?1, respectively, so the level of chitosan supplemented in the diet should be between 2.13 and 2.67 g kg?1.  相似文献   

12.
A growth trial and a digestibility trial were conducted to evaluate the efficacy of carbohydrase supplemented to practical shrimp feeds. The 5‐wk growth trial investigated the effects of carbohydrase supplementation at 0, 0.01, 0.02, 0.03, 0.04, and 0.05% in soybean‐based diets on the performance of juvenile Pacific white shrimp, Litopenaeus vannamei. No significant differences were observed in final biomass, final mean weight, weight gain, feed conversion ratio, and survival across all treatments. The digestibility trial was conducted to evaluate the effects of carbohydrase supplementation at 0.02%, which is the recommended dose by the company that developed the carbohydrase on apparent digestibility coefficients of dry matter, protein, and energy of Pacific white shrimp. Protein digestibility was significantly improved when fed diets contained 0.02% carbohydrase in contrast with the basal diet. No significant differences were found in apparent digestibility coefficients of dry matter and energy. Based on the positive results on protein digestibility, further research regarding the efficacy of exogenous enzymes and their application is warranted.  相似文献   

13.
The objective of this study was to demonstrate the feasibility of four diets formulated to contain increasing levels (0, 50, 100 and 150 g kg?1 of diet) of grain distillers dried yeast (GDDY) in production diets for Litopenaeus vannamei, reared in outdoor tanks or production ponds. The production pond trial was carried out in 16, 0.1‐ha ponds using four replicates per diet. Juvenile shrimp (38.1 ± 4.26 mg, initial weight) were stocked at 30 shrimp m?2 for a 16‐week period. The same four diets and a commercial reference diet were offered to shrimp maintained in outdoor tanks over a 12‐week period. A total of 20 tanks were stocked with juvenile shrimp (3.05 ± 0.22 g, initial weight) obtained from production ponds at a density of 30 shrimp per tank (40 shrimp m?2). At the conclusion of these trials, mean final weight ranged from 19.77 to 23.05 g, yield ranged between 4760 and 5606 kg ha?1, survival ranged from 69.6% to 89.4%, and feed conversion ratio (FCR) was between 1.02 and 1.23. Shrimp reared in the outdoor tanks confirmed the results of the pond trial. Mean final weight ranged between 18.12 and 18.97 g, survival ranged from 93.3% to 98.3%, and FCR was between 1.25 and 1.29. In both trials, there were no significant differences regarding mean final weight, FCR and survival among dietary treatments. Based on this study, GDDY up to 150 g kg?1 of diet can be used in L. vannamei commercial feed formulation.  相似文献   

14.
This study was designed to evaluate the efficacy of eight sources (designated A–H) of soybean meal (SBM) which included six new non‐genetically modified soya varieties in practical feed formulation for Pacific white shrimp, Litopenaeus vannamei, using both growth and digestibility trials. A soybean meal‐based reference diet was formulated using conventional soybean meal (527 g kg?1 diet), which was then replaced on an isonitrogenous basis with various other experimental soybean meals. In a 6‐week growth trial, shrimp in four replicate tanks per dietary treatment (10 shrimp per tank, initial weight 0.52 ± 0.04 g) were cultured in a recirculating system. There were no significant differences with respects to per cent weight gain and survival across all dietary treatments; however, final weights and feed conversion ratio (FCR) were lower in shrimp offered diet 3. Apparent digestibility coefficients for the eight (A–H) different soybean meals were determined in L. vannamei for dry matter (ADMD), gross energy (ADE) and crude protein (ADP) using 10 g kg?1 chromic oxide as inert marker with 70 : 30 replacement techniques. Coefficients ranged from 71.3% to 88.3%, from 76.6% to 91.3% and from 93.6% to 99.8%, for ADMD, ADE and ADP, respectively. Improved digestibility values were observed in soybean C which was characterized by crude protein (471 g kg?1), crude fat (97 g kg?1), low cooking temperature (180 °C), higher nitrogen solubility index (689 g kg?1) and protein dispersibility index (619 g kg?1). This indicates that new lines of soybean meal can be used to improve digestibility coefficients in shrimp feeds.  相似文献   

15.
Two experiments were conducted to determine the effects of phytase on growth, apparent phosphorus (P), calcium (Ca), iron (Fe), zinc (Zn), magnesium (Mg), and copper (Cu) absorption, and apparent protein digestibility by striped bass Morone saxatills fed a high phytate diet. In experiment one, four diets with graded levels of phytase supplementation, 0, 500, 1,000, and 2,000 phytase units/kg of diet (PUkg), and a diet supplemented with inorganic P (positive control, total P, 0.73%; phytin P, 0.35%) were assigned to duplicate tanks, and were fed to fingerling striped bass for 16 wk. A digestibility trial was conducted at weeks 16–18, using 0.5% Cr2O3 as an indigestible marker in the diets. Phytase was sprayed post-extrusion on the basal diet (P-total, 0.58%; P-phytin, 0.35%). Experiment two consisted of a 2-wk digestibility trial with three treatments: 0 (basal; total P, 0.73%; phytin P, 0.34%), 1,000, and 2,000 PU/kg, assigned to four, three and three replicate tanks respectively. Each tank contained an average of 20 striped bass (mean weight: 400 9). The diet used was similar to the basal in experiment one, which was modified to have low essential trace mineral concentrations, in order to increase the sensitivity of the assay. In experiment one, significant improvements (P≤ 0.05) in growth, feed conversion ratios, and vertebral and scale ash concentrations of fish at the end of the experiment were achieved with either added inorganic P or increasing phytase supplementations. Results from both digestibility trials indicated that P absorption was improved with the addition of at least 500 PUkg. Absorptions of Ca and Fe were significantly increased (P≤ 0.05) and Zn absorption marginally improved (P≤ 0.06) when at least 2,000 PU/kg was supplemented to the diet. Protein digestibility, Mg and Cu absorption were not significantly different in any treatment. Whole carcass P retention was significantly improved with the addition of 1,000 PU/kg, and 2,000 PU/kg, when compared to fish fed the basal diet, 500 PU/kg and positive control treatments. Results from these experiments indicate that phytase supplementation of at least 1,000 PU/kg is adequate to maintain growth rate and health comparable to an inorganic P supplemented diet. In addition, bioavailability and utilization of P is increased with increasing phytase supplementation. Diet supplementation of 2,000 PU/kg increased Ca, Fe, and Zn digestibility by striped bass fed a high phytate diet.  相似文献   

16.
The ability of Litopenaeus vannamei (initial mean weight: 0.96 ± 0.02 g) to utilize different levels of cornstarch was examined in terms of growth indices, body composition, digestibility and microscopic structure of the hepatopancreas. Six isonitrogenous semipurified diets were fed to satiation to shrimp for 8 weeks in triplicate tanks (30 shrimps per tank) connected to a natural brackish water (6–8 g L?1) recirculating system. Diets contained different levels of cornstarch (100, 150, 200, 250, 300 and 350 g kg?1) as the source of carbohydrate and were balanced using cellulose. Weight gain (WG), survival rate and feed conversion rate (FCR) were considerably affected by cornstarch levels of diets. The highest WG (453.6 g kg?1) and best FCR was observed in shrimp fed the 150 g kg?1 (cornstarch level) diet and was significantly (P < 0.05) higher than those fed diets containing 250–350 g kg?1 cornstarch. However, the survival rate reached maximum in shrimp fed the 100 g kg?1 diet (96.7), some 30% higher than the lowest rate, which was found in shrimp fed the 250 g kg?1 diet. Body lipid tended to be higher in shrimp fed diets with higher cornstarch levels. The apparent digestibility of dry matter and crude fat increased with increasing levels of cornstarch and, hence, decreasing levels of cellulose. In addition, histological study on shrimp fed 10–350 g kg?1 diets exhibited histological changes. The overall conclusion was that the optimum cornstarch level may be set at 100–200 g kg?1 when the diets contain 380 g kg?1 protein.  相似文献   

17.
The effects of dietary astaxanthin supplemented at 0, 40, 80 or 150 mg astaxanthin kg−1 on growth, survival, moult frequency, osmoregulatory capacity (OC) and selected metabolic and haematological variables in Litopenaeus vannamei acclimated to low‐salinity water (3 g L−1) were evaluated. Supplemented astaxanthin at 80 mg kg−1 improved growth, survival and moult frequency in shrimp. The lowest OC was also exhibited in shrimp fed with dietary astaxanthin at 80 mg kg−1. Shrimp haemolymph concentrations of glucose, lactate, haemocyanin and total haemocyte count were all significantly enhanced by feeding the diet supplemented with 80 mg astaxanthin kg−1 compared with shrimp fed with the other diets. On the basis of these results, dietary astaxanthin supplementation of 80 mg kg−1 is recommended for juvenile L. vannamei cultured in low‐salinity water.  相似文献   

18.
A growth trial was conducted to determine the effects of inclusion of whole shrimp floc or floc fractions to a control diet on growth and survival of shrimp (Litopenaeus vannamei). The floc sample was collected from marine shrimp culture tanks and partially fractionated by extraction with water, acetone and hexane. A series of diets was manufactured by inclusion of whole floc (intact or ground), each of the fractions or their combination to a control diet. These diets were fed to shrimp (approximately 1.0 g) in an indoor laboratory under flow‐through conditions for 8 weeks. It was found that addition of whole floc (200 g kg?1) or floc fractions (24–200 g kg?1) to the control diet improved (P < 0.05) shrimp growth rate without affecting (P > 0.05) shrimp survival (>81.3%). Although inclusion of whole floc reduced the crude protein and crude fat contents and gross energy of the control diet, shrimp fed the whole floc‐supplemented diets obtained the highest (P < 0.05) growth rates (1.01 and 1.03 g week?1) among the shrimp fed the 11 tested diets including two control (0.81 and 0.85 g week?1), two commercial (0.45 and 0.71 g week?1) and five floc‐fraction‐added (0.91–1.00 g week?1) diets. Many bioactive compounds in the floc that possibly affected shrimp growth were also analysed and quantified.  相似文献   

19.
A 4‐week feeding trial was conducted to determine the effects of oxidized fish oil (OFO, POV: 234.84 meq kg?1) on growth performance and oxidative stress of Litopenaeus vannamei. Five diets containing various OFO levels (0, 25, 50, 75 and 100 g kg?1) with the same dietary lipid level were fed to L. vannamei. The results showed that the body weight gain and the specific growth rate of the shrimp fed with 50, 75 and 100 g kg?1 of OFO diets decreased significantly (P < 0.05), whereas the hepatosomatic index increased significantly (P < 0.05). The malondialdehyde concentrations in the serum and muscle of the shrimp fed with 50, 75 and 100 g kg?1 of OFO diets were significantly higher than that of the shrimp fed with fresh fish oil (P < 0.05). The total antioxidant competence decreased significantly compared with the control group. Therefore, dietary OFO affects the growth performance and increases the oxidative stress of shrimp.  相似文献   

20.
This study was to assess effects of the pretreatment in all‐plant based diets with microbial phytase on phosphorous utilization and growth performance of Nile tilapia (Oreochromis niloticus). Pretreatment trials were conducted using phytase at graded doses to determine the optimal dose of phytase. Available phosphorus (P) levels increased significantly with the increased doses of phytase and the dose of 1000 U kg?1 was most efficient. Based on the pretreatment trials, plant based diets for Nile tilapia were formulated by pretreating with phytase at 1000 U kg?1. Experimental diets were supplemented with graded levels of mono calcium phosphate (MCP) at 25, 18.75, 12.5, 6.25 and 0 g kg ?1 diet. In addition, there were three controls: one phytase control, one inorganic P control and one pretreatment control. The results showed that diets pretreated with phytase gave better growth performance, feed conversion ratio and protein efficiency ratio of Nile tilapia compared with the phytase control diet and pretreatment control diet (P < 0.05). There were no significant differences in growth performance of Nile tilapia between the inorganic control diet and phytase pretreated diets supplemented with MCP at 25, 18.75 and 12.5 g kg?1 (P > 0.05), which resulted in significantly better performance than those at 6.25 and 0 g kg?1 (P < 0.05). Dietary interaction effects of phytase were observed for phosphorus retention efficiency and phosphorus load. Apparent digestibility coefficient of P (ADCp) was improved significantly by phytase pretreatment (P < 0.05). No significant difference was detected on ADC of crude protein among all experimental diets (P > 0.05).  相似文献   

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