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1.
Four commercially available proteolytic enzymes active over a wide pH range were assessed as shrimp feed additives. Feeds were formulated to contain 1% of the test enzymes by weight. A feed of the same composition with no enzyme addition served as a control. In vitro feed protein digestibility of the feeds was determined using a modified pepsin digestibility method. In vitro protein digestibility results indicated that commercially available proteases added to a shrimp feed formulation and then hot pelleted/dried did retain enzyme activity. Feeds exhibited low weight losses through leaching (≤ 10.9%) and low or no losses of protein content (≤ 2.7%), indicating that the test feeds were available in their entirety to the shrimp. An 8-week feeding trial using the enzyme-supplemented feeds was conducted to evaluate shrimp growth. Mean shrimp survival was high for all treatments (> 90%). One-way analysis of variance did not detect significant differences (P > 0.05) among feeds in terms of survival, weight gain, specific growth rates and feed–weight gain ratios. Although in vitro digestibility indicated the presence of active enzymes in the feed, the feeding trial revealed that shrimp growth was not enhanced by the inclusion of proteases in these feeds. This study provides sufficient proof to emphasize the importance of in vivo investigations before enzyme-supplemented feeds are used with shrimp.  相似文献   

2.
To improve feed management strategies for the semi‐intensive culture of Litopenaeus vannamei, outdoor tank and pond trials were conducted. In the tank trial, shrimp (35 shrimp/m2, n = 4) were offered feed for 6 weeks based on a standard feeding protocol (SFP, designed as T100) with five variations (T80:90:100, T90, T90:100, T100:110, T110) of this protocol produced by varying the feed inputs and expressing the treatments as a percentage. Results demonstrated no significant differences in survival rate and feed conversion ratio (FCR) among treatments. The mean final weight and final biomass in the treatments T100:110 and T110 were significantly higher than those in treatment T90 but were not different from the other treatments. In the pond trial, juvenile shrimp (28 shrimp/m2, n = 4) were stocked into twelve 0.1‐ha ponds over a 16‐week period. Three feeding protocols were evaluated including a SFP, a 10% reduction in the SFP (SFP:90), and a variable feed input (SFP:80:90:100), which included 80% SFP at week 4th–8th, 90% SFP from week 9th–12th and 100% SFP for week 12th–16th. There were no significant differences in growth performance and economic return among treatments. Based on previous studies, in which higher feed inputs were evaluated, and results of this study, it does not appear to be economically beneficial to use high feed inputs. Instead, feed input could be either applied at a standard ration to optimize growth and economic return or at restricted rations to reduce FCR (feed cost) albeit at the expense of some growth.  相似文献   

3.
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   

4.
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   

5.
A growth trial and a digestibility trial were conducted to evaluate the efficacy of phytase supplemented to practical shrimp feeds. The 5 weeks growth trial evaluated the effects of phytase supplementation in replete phosphorus (P) diets on the performances and compositions of juvenile Pacific white shrimp, Litopenaeus vannamei. No significant differences were observed in final biomass, final mean weight, weight gain, feed conversion ratio (FCR), protein retention and survival across all the treatments. Shrimp reared on the P deficient diet had significantly higher P retention and lower whole body P levels as compared to shrimp fed the other diets. Copper content in the whole shrimp body was significantly increased in the treatment supplemented with 1,000 IU kg?1 feed phytase. The digestibility trial was conducted to study the combined effects of phytase supplementation levels and diet type (plant‐based versus fishmeal‐based) on apparent digestibility coefficients of Pacific white shrimp, Litopenaeus vannamei. There were no effects of diet type so the data was combined. Phytase incorporation at both 500 and 2,000 IU kg?1 significantly improved protein digestibility, whereas P digestibility was enhanced when 2,000 IU kg?1 phytase was supplemented to the diet. Apparent digestibility coefficients of alanine, arginine, aspartic acid, cysteine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, ornithine, phenylalanine, proline, serine, threonine, tyrosine and valine were significantly increased when fed diets contained 500 and 2,000 IU kg?1 phytase supplementation. Results of this work demonstrate that under the conditions of the study growth was not enhanced by phytase supplementation in P replete diets. However, nutrient retention for Cu and digestibility of P, protein and a number of amino acids were enhanced.  相似文献   

6.
The objective of this study was to evaluate the effect of dietary and water supplementation of probiotic Streptococcus phocae PI80 on growth, immune response and feed utilization of tiger shrimp Penaeus monodon in earthen ponds. The probiotic bacterium S. phocae PI80 was cultured in large fermenter (50 L) by adding additional carbon source in the form of molasses and glucose along with yeast extract as nitrogen source to enrich S. phocae PI80 biomass. This enriched S. phocae PI80 was administered to shrimp in feed (6.5 × 1013 bacterial cells mL?1) as well as in pond water (5 L/pond). Shrimp growth performance was significantly improved (P < 0.05) in 120 days culture when the average body weight of treated molasses + yeast extract (MY) (28.41 ± 0.874 g), glucose + yeast extract (GY) (27.013 ± 0.698 g) was significantly higher than control (23.63 ± 0.684 g). Food conversion ratio FCR was also found to be reduced significantly in ponds treated with probiotics when compared with control pond (1.89 ± 0.09). Vibrio and luminescent bacteria were found to be lower in the treatment receiving MY group, and we hypothesize that this may lead to greater shrimp survival. Furthermore, fermentation product of S. phocae PI80 added to pond water and feed additives enhanced the shrimp immune system. The results indicated that total haemocytes count (THC), phenoloxidase (PO) activity, NBT reductase assay and phagocytic activity significantly increased in shrimps treated with S. phocae PI80. Our study demonstrates that administration of S. phocae PI80 in the water and feed at 6.5 × 1013 colony‐forming units (CFU) mL?1 bacterial cells induce immune modulation and enhances the immune ability of P. monodon in pond‐reared shrimp and increased the shrimp production.  相似文献   

7.
Knowledge of apparent protein digestibility (APD) is required for optimization of feed formulae for the production of marine penaeid shrimp. The purpose of this study was to evaluate an in vitro method for determining APD in marine penaeid shrimp using gut enzyme extracts. A high correlation (r2 = 0.95) was shown between single‐ingredient APD values for fish meal diets using in vivo methodology and those derived from in vitro testing of ingredients. A second study showed positive correlation (r2 = 0.71) between in vitro APD of selected purified and semipurified ingredients and their reported in vivo APDs. This correlation was much higher for purified ingredients (r2 = 0.93) versus less‐refined ingredients (r2 = 0.24). A third trial compared in vitro APD at three different enzyme extract pH values and showed that for most protein sources, APD was significantly highest (P < 0.05) at pH = 7.0 and lower at pH = 6.1 or 7.9, indicating a neutral pH optimum for this methodology.  相似文献   

8.
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   

9.
Litopenaeus vannamei were stocked in 25 clear‐water 500‐L tanks at 100 shrimp m?2 and in 25 green‐water 1000‐L tanks at 60 animals m?2. Four diets were formulated to include krill meal at 10, 50 or 110 g kg?1; or krill oil at 25 g kg?1 by replacing fish meal, fish oil, soybean lecithin and cholesterol. Diets had similar levels of crude protein, total energy and essential amino acids. After 72 days, shrimp reared in clear and green water showed no differences in performance among diets. In clear water, shrimp attained 13.1 ± 0.59 g body weight, 1.00 ± 0.06 g week?1 growth, 81.4 ± 7.3% survival, 780 ± 118 g m?2 yield, 16.9 ± 1.8 g shrimp?1 apparent feed intake (AFI), and 2.18 ± 0.29 food conversion ratio (FCR). In green water, shrimp attained 14.3 ± 0.81 g body weight, 1.04 ± 0.09 g week?1 growth, 91.4 ± 5.4% survival, 569 ± 69 g m?2 yield, 20.9 ± 3.2 g shrimp?1 AFI, and 2.22 ± 0.34 FCR. Diets containing krill meal or krill oil were able to fully replace the protein and lipid value of fish meal, fish oil, soybean lecithin and cholesterol at no cost to performance.  相似文献   

10.
In vivo and in vitro protein digestibility of 0% to 60% soybean meal protein (SBM) substitution from fishmeal protein was conducted for bagrid catfish Mystus nemurus juveniles. Seven experimental diets containing 35% protein and 15% lipid were fed to bagrid catfish to determine the in vivo protein digestibility. In vitro methods were determined using pH stat, pH shift, spectrophotometric assay and sodium dodecyle sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) with different enzyme mixtures (crude intestinal extract of bagrid catfish, Lazo 1‐enzyme, Hsu 3‐enzyme, Saterlee 4‐enzyme). In vivo and in vitro protein digestibility decreased with increased SBM protein substitution with highest tolerance level of 10% (in vivo). pH stat and pH drop methods showed the highest degree of hydrolysis (DH) and relative protein digestibility (RPD) using Saterlee 4‐enzyme system. However, pH stat method showed highest correlations (r2 = 0.9263) with the in vivo results using crude intestinal enzyme extract compared to other enzyme systems. The highest correlation of the in vitro methods using crude intestinal enzyme extracts of bagrid catfish was determined using spectrophotometric assay (r2 = 0.9284) followed by pH stat (r2 = 0.9263), SDS‐PAGE (r2 = 0.8348) and pH drop (r2 = 0.6777). All the in vitro methods tested are suitable to rapidly determine protein digestibility for bagrid catfish except for pH drop.  相似文献   

11.
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   

12.
The efficacy of a commercial microbial product was tested in commercial tiger shrimp, Penaeus monodon (Fabricius), ponds for one culture period in Kuala Selangor, Malaysia. Four ponds with replicates for treatment and control were used. The pond bottom was dried but the organic sludge was not removed as normally practised in pond preparation. The ponds were stocked with 15 post‐larvae at the rate of 31.m?2. Physical, chemical and biological parameters of the pond were analysed every 2 weeks during the culture period. Water quality parameters remained within the optimum range for shrimp culture except for ammonia‐nitrogen being significantly higher in control ponds and silica in treated ponds. Benthic organisms were not found in any of the ponds. The average counts of different bacteria were not significantly higher in treated ponds than control. Because of poor health, the shrimp were harvested earlier (72 days) than the usual 120 days. An average of 875.60 ± 67.00 kg shrimp ha?1 was obtained in treated ponds with a feed conversion ratio (FCR) of 1.57 ± 0.10 and survival rate of 42.35 ± 5.37% compared with 719.50 ± 130.94 kg shrimp ha?1, 2.99 ± 0.70 and 21.25 ± 3.26%, respectively, in control ponds. Neither the microbial product nor the frequent water exchange was effective in overcoming the problems caused by the poor pond bottom.  相似文献   

13.
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   

14.
The use of the same water over multiple culture cycles in a biofloc technology system can be highly beneficial. This study evaluated the effect of different levels of biofloc‐rich water on selected water quality indicators and on the productive performance of Pacific white shrimp, Litopenaeus vannamei, juveniles (3.5 g) stocked at 312 juveniles/m3 and cultured under conditions of no water exchange. The study was performed over a 30‐d period in an 800‐L tank system. A total of four biofloc enrichment levels (25, 50, 75, and 100%) and control (0%) were tested with three replicates each. Significant differences in nitrogen compounds were found between the biofloc‐enriched water and the zero‐enrichment treatment. No statistically significant differences among the biofloc‐enriched treatments were found in survival, final weight (8.25 g), and feed conversion ratio (FCR) (1.08). The shrimp raised in clear seawater (i.e., a 0% biofloc enrichment) were significantly smaller (7.37 g vs. 8.25 g) and showed a higher FCR (1.52 vs. 1.08) than the shrimp cultured in the biofloc‐rich water. Nevertheless, no differences in yields were found between treatments. The results of this study suggest that culture in biofloc‐enriched water produces higher levels of water quality and shrimp performance than culture in natural seawater.  相似文献   

15.
The present study was conducted to evaluate the effect of varying dietary protein level on pond water quality and production parameters of white shrimp Litopenaeus vannamei (Boone). Experimental units consisted of nine 400‐m2 earthen ponds with a low water exchange. Two treatments were tested: treatment HP consisted of shrimp fed a high‐protein diet (40%) during the whole grow‐out, and treatment LP consisted of the use of a low‐protein diet for the complete farming period. No differences on any of the water quality parameters were observed among treatments. Excellent survival (over 85%) and feed conversion ratios (around 1.6), and acceptable growth (over 12 g) and biomass (from 1721 to 1793 kg ha?1) were recorded in all experimental ponds. No significant differences in any of the production parameters were found among treatment groups.  相似文献   

16.
A feeding trial was conducted to evaluate the potential of replacing fish meal with co‐extruded wet tuna viscera and corn meal in diets for juvenile white shrimp Litopenaeus vannamei. Five practical diets were formulated to contain 30% crude protein and 16.6 kJ g?1. The feeding experiment was carried out in a recirculating seawater system with fifteen 25‐L tanks with 15 shrimp per tank. Each dietary treatment was fed in triplicate in a completely randomized design for 41 days. Percent weight gain (WG%), survival (S%) and feed conversion ratio (FCR) were calculated, comparisons of these parameters showed no statistical differences (P>0.05) among treatments. The shrimp almost tripled their weight during the feeding trial. Under the experimental conditions S%, WG% and FCR were either improved or were not significantly influenced by the replacement of fish meal with double co‐extruded viscera+corn, except for a slight increase in feed consumption without affecting FCR. Hence, this product can be included by up to 40% in practical shrimp diets without any detrimental effects.  相似文献   

17.
Effects of temperature and processing on the stability of a commercial protease were assessed in an in vitro trial followed by growth trials with white shrimp and tilapia. Results showed that the protease has a high heat stability against pelleting, and it could hydrolyse dietary proteins during feed processing. In Exp. 2, white shrimp (3.3 g) fed low fish meal (FM) diet (LFD) with protease addition had similar growth to that fed high fish meal diet, and both had higher weight gain (WG) and lower feed conversion ratio (FCR) than that fed LFD without protease addition (P < 0.05). In Exp. 3, compressed (CD) or extruded (ED) diets containing 30 g kg?1 or 90 g kg?1 FM were supplemented with or without protease and then fed to tilapia (1.7 g) for 8 weeks. WG was improved and FCR decreased (P < 0.05) by the supplementation of protease in 30 g kg?1 FMCD, but not in 90 g kg?1 FMCD and ED diets when compared to those diets without protease supplementation. The digestibility trial with CD indicated the improved apparent digestibilities of dry matter and crude protein by dietary protease in 30 g kg?1 FMCD, but not in 90 g kg?1 FMCD. Results above showed that the protease has a high heat stability and the supplementation of protease in CD with low FM level can improve the growth of shrimp and tilapia.  相似文献   

18.
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   

19.
Organic acids or their salts are promising feed additives for aquatic animals to improve growth performance. We determined the effect of supplementing diets with sodium salts (formate, acetate, lactate, propionate, butyrate, fumarate, succinate and citrate) on trypsin and chymotrypsin activities, in vitro digestibility and zootechnical performance in the whiteleg shrimp (Litopenaeus vannamei). Shrimp trypsin and chymotrypsin activity increased in the presence of acetate and propionate and decreased in the presence of lactate and citrate. The highest in vitro protein digestibility of the experimental diets, using shrimp enzymes, was obtained for diets containing fumarate and succinate, which was significantly greater than the control diet (no supplements). In a growth trial, the highest final weights were in shrimp fed diets supplemented with fumarate, succinate, butyrate and propionate, increasing 53%, 46%, 38% and 29%, respectively, compared to the control. Shrimp that were fed diets with fumarate digested more feed and had a feed conversion ratio 23% higher than the control shrimp. Shrimp survival did not differ among treatments. We concluded that organic salts in the diet modify digestive enzymatic activity and in vitro protein digestibility of whiteleg shrimp. Fumarate, succinate, butyrate and propionate have potential as feed additives for L. vannamei.  相似文献   

20.
The objective of this study was to demonstrate the feasibility of partial substitution of menhaden fish oil by alternative lipid sources (soybean oil, poultry grease and flaxseed oil) in non‐marine protein‐based shrimp production diet, its influence on fatty acid profile and its final product flavour. Results for the pond study (17 weeks) showed no differences (P ≥ 0.05) in shrimp production among different test diets. Production ranged from 5070 to 5363 kg ha?1; mean final weight, 18.0 to 21.6 g; weekly growth, 1.04 to 1.25 g; survival, 65.6 to 75.4%; and FCR, 1.37 to 1.45. Results from the tank trial (12 weeks) confirmed these findings, final weight, 13.8–14.8 g; weekly growth, 1.1–1.2 g; survival, 92.5–98.3%; FCR, 1.05–1.11; and final standing crop, 4738–5024 kg ha?1. The fatty acids profiles of edible tail muscle reared on the various diets displayed a similar fatty acid profile to that of the diets. The sensory test showed no statistical differences in texture, appearance, aroma and flavour between the shrimp fed diets containing menhaden fish oil and soybean oil. These studies demonstrated that practical shrimp feeds containing non‐marine protein ingredients and a percentage of fish oil replaced by alternative lipid sources had no negative impact on mean final weight, weekly growth, survival, FCR, final standing crop, fatty acids profile and organoleptic properties of Litopenaeus vannamei.  相似文献   

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