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1.
The white shrimp Litopenaeus vannamei, fed immunostimulant‐free, 0.2%β‐glucan and 0.06% glycyrrhizin diets for 18 days, respectively, were challenged with Vibrio alginolyticus at 6.4 × 104 CFU shrimp?1. The total haemocyte count (THC), phenoloxidase (PO) activity, respiratory burst (RB) and superoxide dismutase (SOD) activity changes for a 120‐h period were investigated, and shrimp mortality was also recorded. The results showed that PO activity, RB and SOD activity were significantly higher in shrimp fed the two immunostimulant diets after 18 days than those in shrimp fed immunostimulant‐free diets. The THC and SOD activity decreased significantly from 0 to 24 h post challenge, and then reverted to normal levels at 96 and 72 h respectively. The values for PO activity and RB increased from 0 to 48 h post challenge. Compared with those fed the control diets, shrimp fed immunostimulants had significantly higher PO activity and RB values at 120 h post challenge. Mortalities after challenge with V. alginolyticus were significantly lower in shrimp fed with β‐glucan or glycyrrhizin than in those fed with a diet without immunostimulants. It was concluded that dietary β‐glucan and glycyrrhizin increased the shrimp immunity. Furthermore, β‐glucan caused an increase in some immune parameters 12 h earlier than glycyrrhizin after V. alginolyticus challenge.  相似文献   

2.
The aim of this study was to examine the effects of the immunostimulant combination (IC) containing β‐glucan, A3α‐peptidoglycan, vitamin C and vitamin E on the growth performance, non‐specific immunity and protection against Vibrio harveyi infection in cobia (Rachycentron canadum). Fish were fed diets containing six graded levels of IC (0, 1, 2, 3, 4 and 5 g kg?1 diet) for 8 weeks. The results showed that the survival rate ranged from 81.1 to 84.4% with no significant difference among all the groups (P > 0.05) after the feeding experiment. Dietary IC significantly increased the specific growth rate (SGR), serum lysozyme, alternative complement pathway (ACH50) activity, phagocytosis percentage (PP) and respiratory burst activity of head kidney macrophages of cobia. Moreover, feeding of supplemented diets containing 3.0 g kg?1 IC resulted in significantly lower mortality against the pathogens, V. harveyi compared with the control group. To elevate the growth and immune resistance ability of cobia, the optimal dose of dietary IC administration, determined by second‐order polynomial regression analysis was 3.43 and 2.71 g kg?1 diet, respectively, on the basis of the SGR and mortality after challenge with V. harveyi.  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.
A feeding trial was conducted to evaluate the efficacy of replacing fish meal (FM) with blood meal (BM), poultry by‐product meal (PBM), meat and bone meal (MBM) and shrimp head meal (SHM), rapeseed meal (RM) and peanut meal (PM) on a digestible basis of crude protein and lysine and methionine in five practical diets for the Pacific white shrimp at the FM levels of 300, 250, 200, 150 and 100 g kg?1 under laboratory conditions. Each of the five experimental diets was hand‐fed to four replicate tanks of shrimp with an average weight of 0.33 ± 0.03 g to satiation at each meal. The shrimp were fed three times a day over a six‐week period. The per cent weight gain of initial body weight (WG%) was significantly lower in shrimp fed 100 g kg?1 FM diet, but the value for hepatosomatic index (HSI) and the level of blood urea nitrogen (BUN) tended to be higher in shrimp fed 100 g kg?1 FM diet than those in shrimp fed other diets. The lowest value for feeding rate (FR) occurred for shrimp fed the basal diet and was significantly lower than that in shrimp fed the FM diets at 100–150 g kg?1. Shrimp fed diets containing 200 g kg?1 or lower FM had significantly lower feed utilization than those fed the 250 g kg?1 FM diet and the basal diet. The protein efficiency ratio (PER) in the shrimp fed the basal diet was significantly higher than in the other FM diets. Decreasing the FM replacement level significantly reduced nutrient digestibility except in the cases of ash and gross energy, but it did not affect the survival, condition factor (CF), body composition, digestive enzyme activity or plasma transaminase activity. The results of the study indicate that feeding a diet formulated on a digestible basis and involving FM replacement with other protein sources at a greater replacement proportion will not produce a level of shrimp growth equal to that achieved by feeding the basal diet.  相似文献   

5.
In this study, we replaced fish meal with peanut meal (PM) in isonitrogenous and isolipidic diets for Pacific white shrimp at inclusion levels of 0, 70, 140, 210, 280 and 350 g kg?1. The diets were hand‐fed to three independent groups of shrimp three times a day over a 6‐week period. Shrimp fed PM diets at a level of 280 g kg?1 or higher had lower per cent weight gain compared with those fed the basal diet, whereas shrimp fed PM diets at 140 g kg?1 or higher had a lower feed utilization and protein efficiency ratio compared with shrimp fed the basal diet. The feeding rate in shrimp fed PM diets at 350 g kg?1 and the survival and protease activity in shrimp fed PM diets at 210 g kg?1 or higher were lower than that in shrimp fed the basal diet. Diets containing 280 g kg?1 or higher of PM caused an increase in the whole‐body moisture content of the shrimp, but decreased whole‐body protein and ash contents compared with the basal diet. Nutrient digestibility was lower or tended to be lower in shrimp fed a PM diet compared with those fed the basal diet. The activities of peroxidase and acid and alkaline phosphatases in plasma decreased with increasing levels of PM inclusion up to 210 g kg?1. Superoxide dismutase activity decreased at dietary PM levels of 280 g kg?1 or higher. Aflatoxin B1 residue in the muscle was not affected by any of the treatments and remained low. The data suggest that up to 140 g kg?1 of PM could be included in practical diets for Pacific white shrimp.  相似文献   

6.

This study examined the effects of dietary melamine (MEL) and cyanuric acid (CYA) singly and in combination on growth, nutrient utilization, immunological responses, oxidative stress, and histological changes in Pacific white shrimp. Seven experimental isonitrogenous (35%) and isolipidic (8%) diets were formulated, namely diet 1 (a control diet without MEL and CYA); diets 2–5 (with MEL and CYA at 2.5?+?2.5, 5?+?5, 7.5?+?7.5 and 10?+?10 g kg?1 diet); diet 6 (with only MEL at 10 g kg?1 diet) and diet 7 (with CYA alone at 10 g kg?1 diet). The shrimp with initial body weight 2.37?±?0.02 g were fed with these diets for 10 weeks. The results indicate that all the diets with MEL and CYA singly or in combination had adverse effects on growth and nutrient utilization relative to the control diet (p?<?0.05). Total protease and trypsin activities were significantly lowered by all diets containing MEL (p?<?0.05). Haemolymph parameters, including total hemocyte count, phenoloxidase (PO) activity, respiratory burst, and lysozyme activity, were significantly decreased (p?<?0.05) in shrimp receiving MEL alone (10 g kg?1 diet) and at high combination dosages (10?+?10 g kg?1 diet). Moreover, MEL and CYA induced oxidative stress, damaged hepatopancreas, decreased antioxidant responses, increased lipid peroxidation, and caused abnormality of hepatocytes.

  相似文献   

7.
Two trials were conducted to evaluate the growth, survival and hepatopancreas histology of the Argentine red shrimp Pleoticus muelleri (Bate, 1888) fed different levels of vitamin E and butylated hydroxytoluene (BHT) in a semipurified diet. The diets contained 0, 100, 600 or 1500 mg vitamin E kg?1 and 16 mg BHT kg?1 diet (trial 1) and 0, 1250, 1500, 1750 or 2000 mg vitamin E kg?1 diet, squid mantle and vitamin‐free diet as a control (trial 2). After 30 days (trial 1), survival ranged between 43% and 64%, and the percentage weight gain of the shrimp varied from 22% to 31% with no significant differences among treatments (P<0.05). After 40 days (trial 2), survival of shrimp fed the diet with no vitamin E and squid mantle was significantly lower (62%) than the other treatment (86–90%). Shrimp fed diets containing vitamin E from 1250 to 1750 mg kg?1 exhibited increased weight gain (34–65%); however, a significant difference was observed for shrimp fed the diet containing 2000 mg kg?1. Histological results yielded differences among treatments. In shrimp fed 1750 mg kg?1 of vitamin E, the functional morphology of the organ was normal, with abundant secretion in the tubules. Signs of malnourishment such as cellular and nuclear retraction, desquamation of cells and hipertrofia, were evident in the hepatopancreas of shrimp fed the other diets. The results indicate that optimal vitamin E requirement for P. muelleri under the present experimental conditions appears to be approximately 1750 mg vitamin E kg?1 diet.  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 5-week feeding trial was conducted to evaluate the effects of biofloc in situ and commercial probiotic supplementation on white shrimp (1.87?±?0.03 g) inorganic nitrogen control, growth, and immunophysiological response. For this purpose, four treatments were conducted: clear water with no probiotic application (CW), clear water with probiotic application (CW+P), biofloc with no probiotic application (FLOC), and biofloc with probiotic application (BFT+P); each group had three replicates. Growth parameters (final body weight, daily weight gain, specific growth rate) were significantly higher in the two biofloc systems (P?<?0.05), and the FLOC and FLOC+P group did not have a significant difference (P?>?0.05). The immune responses (total hemocyte count, complement component protein, and lysozyme) and antioxidant status (glutathione, catalase) in the CW+P, FLOC, and FLOC+P groups were increased significantly at the end of the experiment compared with the CW group (P?<?0.05), and the FLOC and FLOC+P groups did not have a significant difference (P?>?0.05). Results of a 10-day Vibrio harveyi challenge test show that the survival rates in CW+P, FLOC, and FLOC+P groups were significantly higher (P?<?0.05), and the FLOC and FLOC+P groups did not have a significant difference (P?>?0.05). These results suggest that probiotic addition in the biofloc system had little advantage, but probiotics can improve the immune status of the shrimp in the clear water system. Further, cost-effectiveness analysis showed that the biofloc system was an efficient and economical option for the production of white shrimp.  相似文献   

10.
This experiment was carried out to investigate the effect of feeding low protein diets (~20BFd20.13; ~22BFd22.20; ~24BFd24.32, and ~26BFd26.44) in the presence of the biofloc on the growth performance and feed utilization of (Fenneropenaeus indicus) in comparison with commercial feed of 35% CP as control. The present study was based on application of genetic, nutritional and pathological tools. The biofloc was developed in the low protein diet using molasses as a carbon source. Fifty juveniles F. indicus with an average body weight of 0.52?±?0.03 g were stocked in 50 L plastic tanks. Low protein diets and the control were tested in three replicates over a 112 days feeding trial. There were significant differences in protein, amino acids profile, lipids and fatty acids profile between the control and low diets group in the presence of the biofloc. However, less variation was noticed in the whole body composition (protein, amino acid profile, lipids and fatty acid profiles) of the shrimp between the control and low diets groups in the presence of the biofloc. There were no significant differences in final weight between control and low diets groups. Same trend was noted in the SGR, which did not vary significantly between low protein diets and control. However, the utilization of the biofloc by shrimp as a feed source was evident by the significant differences (P<?0.05) in FCR between low protein diets and control. There was a significant difference in the shrimp survival (%) (P<?0.05) between the low protein diets and the control which ranged between 86.66 % and 66.66 %, respectively. The development of biofloc significantly reduced the TAN, nitrate NO3-N and nitrite NO2-N levels in the low protein diets tanks. Diagnostic of mortality cases revealed that biofloc can serve as a biosecurity system for shrimp farmimg. RAPD-PCR were used to study the epidemiology of Vibrio parahaemolyticus responsible for early mortality syndrome (EMS) isolated from the water of culture system. The OPC5 (GATGACCGCC) primer produced bands ranged from 1 to 8 with sizes from 0.2–5.0 kb.  相似文献   

11.
Integration of tilapia to shrimp culture is currently being practiced to minimize the growth of pathogenic luminous bacteria. The microorganisms that are associated in tilapia may contribute to the inhibition of the growth of Vibrio harveyi through the production of secondary metabolites. In this study, two Bacillus strains (MJA1.1, MJA2.1) isolated from mucus of tilapia were evaluated for their possible application in shrimp culture. The inhibitory property of these isolates against V. harveyi was determined in vitro using co-culture assay in a liquid medium. Also qualitative extracellular enzyme assay was conducted to assess whether the bacterial isolates produce extracellular enzymes. Furthermore, the potential use of these isolates as shrimp feed additive was tested. Thereafter, shrimps were exposed to lethal dose of ammonia (140 mg l?1) to test the effects of the isolates in vivo. The results showed that in vitro co-culture assay after 72 h caused a significant decline in the population of V. harveyi in treatments with potential probiotic isolates. Both isolates showed protease, amylase, and cellulase activities. Although no significant difference was observed in growth, survival was significantly higher in shrimp fed with diets added with either of the isolates. The shrimp exposed to lethal dose of ammonia demonstrated better survival when supplemented with the probionts compared to the control group. Thus, the efficiency of the isolates in inhibiting V. harveyi population and the improvement of survival and resistance of cultured shrimp to ammonia stress indicate their potential as probionts for shrimp culture.  相似文献   

12.
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   

13.
The effect of four iso-nitrogenous and iso-lipidic diets containing soy lecithin and lysolecithin with fish oil (sardine) and palm oil on growth, digestibility, and fatty acid composition of tail muscle and non-muscle portions of tiger shrimp, Penaeus monodon, was evaluated. Shrimp fed with lysolecithin diets had significantly (P?<?0.05) higher daily growth coefficient values (1.40–1.45% day?1) than those fed with soylecithin containing diets (1.32–1.37% day?1). Correspondingly, lysolecithin-supplemented diets showed significantly higher (P?<?0.05) apparent digestibility coefficients (ADC) of fatty acids with both the oils due to higher emulsification ability of small micelle forming by lysolecithin. However, there were no significant differences in survival and FCR among all treatments. The fatty acid composition of the test diets reflected to a certain extent in the fatty acid composition of the muscle and non-muscle portions of shrimp. Arachidonic, eicosapentaenoic, and docosahexaenoic acid contents of muscle and non-muscle portions of shrimp were significantly (P?<?0.05) higher in lysolecithin-supplemented diet compared to soylecithin-supplemented diet. The present results suggest that lysolecithin improved the fatty acid digestibility with its high emulsification properties that reflected in better performance by improving dietary value of palm oil.  相似文献   

14.
A 15‐week growth trial was conducted with juvenile, Pacific white shrimp Litopenaeus vannamei to study the efficacy of using algal meals as a source of highly unsaturated fatty acids in practical diets that are designed to contain no marine protein or oil sources. Based on previous study, a practical diet was designed containing co‐extruded soybean poultry by‐product meal with egg supplement and soybean meal as the primary protein sources for formulations containing 350 g kg?1 crude protein and 100 g kg?1 lipid. To further refine the diets, the fish oil in two of the diets was completely substituted with plant oils and oil originating from microbial fermentation products rich in docosahexanoic acid (DHA) and arachidonic acid (ArA). A commercial shrimp feed was also included in the trial for comparison. The mean values for shrimp final weight (17.8 g), yield (537.7 g m?2 or 703.2 g m?3), survival (98.5%) and feed conversion ratio (1.4 : 1) showed no statistically significant differences between diets. The results suggest that co‐extruded soybean poultry by‐product meal and oil from heterotrophic microalgal fermentation sources can be potential candidates for fish meal and marine oil replacement in shrimp diets.  相似文献   

15.
Farfantepenaeus paulensis juveniles (72 ± 24 mg), were reared in a suspended microbial flocs system and fed practical diets containing increasing amounts of crude protein (250, 300, 350, 400 and 450 g kg?1 CP). Development of microbial flocs was promoted by high aeration rates and fertilization with wheat bran and molasses. Flocs were composed of detritus in the form of flocculated matter colonized by heterotrophic bacteria, cocoid and filamentous cyanobacteria, flagellate and ciliate protozoa and rotifers. Proximate composition analysis of the suspended microbial floc showed CP levels of 304 g kg?1. After 45 days, mean shrimp survival were above 89%, with no significant differences between treatments. Shrimp fed diets with 350 g kg?1 or higher CP content achieved significant higher (P < 0.05) final weight (0.66–0.68 g), weight gain (0.58–0.61 g) and instantaneous growth rate (0.049–0.050), with feed conversion rates (2.17–2.30) significantly lower (P < 0.05). Results show that, when rearing is carried out in a suspended microbial flocs system, dietary CP levels can be kept at 350 g kg?1. Furthermore, results confirm that microbial‐based systems allow shrimp culture without compromising the surrounding environment and shows the possible reduction of production costs and fish meal dependence.  相似文献   

16.
The growth response, total hemocyte count (THC), respiratory burst (release of superoxide anion), phenoloxidase (PO) activity, superoxide dismutase (SOD) activity, nitric oxide synthase (NOS) activity and resistance to the pathogen Vibrio alginolyticus were measured in white shrimp (Litopenaeus vannamei) which had been fed diets supplemented with soybean isoflavones (SI) at 0, 5, 10, 20, 40 mg kg?1 feed for 8 weeks. Dietary SI had no significant influence on survival rate of the shrimp. Significantly greater SGR was observed in treatments with 10, 20 and 40 mg kg?1 SI supplement than that in control (P < 0.05). Shrimp fed a diet with 20 mg kg?1 SI showed significant increase in THC, PO activity, respiratory burst activity, SOD activity as well as NOS activity (P < 0.05). Increased THC, respiratory burst activity, SOD activity and NOS activity were also noticed in shrimp fed SI at 10 or 40 mg kg?1 (P < 0.05). Significant lower cumulative mortality after challenge was observed in shrimp fed diets with SI supplement (10.0–13.3%) than that in control group (36.7%) (P < 0.05). It is therefore concluded that oral administration of SI at 20 mg kg?1 for 8 weeks could enhance the immune ability of shrimp and improve production in shrimp farming.  相似文献   

17.
A 6‐week feeding trial was carried out in glass tanks to determine the effects of partial replacement of fish meal (FM) with a combination of meat and bone meal (MBM), poultry by‐product meal (PBM), blood meal (BM) and corn gluten meal (CGM) in practical diets on the growth, nutrient digestibility and body composition of Pacific white shrimp. Six practical diets were formulated, containing two levels of crude protein (CP) (330 and 380 g kg?1) and similar crude lipid (CL) levels. For the 330 g kg?1 dietary protein level, 0, 357 and 714 g kg?1 FM were replaced by the mixture in Diets 1–3, respectively; while 0, 514 and 784 g kg?1 FM were replaced in Diets 4–6, respectively, for 380 g kg?1 dietary protein level. White shrimp‐fed diets containing 330 g kg?1 CP had significantly lower weight gain compared with white shrimp fed diets containing 380 g kg?1 CP. Increasing the mixture and dietary protein level significantly raised the body ash content of white shrimp. White shrimp fed a low‐protein diet obtained better nutrient digestibility compared with those fed a high‐protein diet.  相似文献   

18.
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   

19.
This study aimed to evaluate the effect of the gradual replacement of fishmeal with fish protein hydrolysate (FPH) and biofloc flour (BF) in the diets of white shrimp Litopenaeus vannamei postlarvae (2 mg). Five diets (420 g kg?1 of crude protein) were formulated, and these replaced 0 (control), 10, 20, 30 and 40% (T0, T10, T20, T30 and T40, respectively) of the fishmeal. A commercial diet was used as an external control. The alternative ingredients FPH and BF were added at a ratio of 1 : 1. After 42 days, the shrimp survival was higher than 99% in all the treatment groups. A regression test indicated that the ideal fishmeal substitution level to obtain optimal zootechnical parameters (final weight, weight gain and protein efficiency) is between 15.16 and 16.5%. In this study, we demonstrated that BF and FPH are potential ingredients that can be used to replace fishmeal in L. vannamei postlarvae diets.  相似文献   

20.
The effects of feeding three natural frozen diets, grass shrimp (Palaemonetes sp.), crayfish (Procambarus clarkii) and fish (Sardina pilchardus) and two semi‐humid artificial diets (based on fish or shrimp powder) to the cuttlefish, Sepia officinalis, were analysed. Growth rate and feeding rate [FR; % body weight (BW) day?1] and food conversions (FC, %) were determined. Cuttlefish fed shrimp grew larger (3.8% BW day?1) and had the highest FC, followed by those fed crayfish, and sardine. The highest FR was obtained for cuttlefish fed crayfish (10.5% BW day?1). Although both artificial diets were accepted, none produced growth. Digestive gland‐to‐body weight ratio (DG/BW ratio) was calculated for animals fed each diet. A positive correlation (r = 0.94) between cuttlefish ingestion FR and DG weight was obtained. Mortality occurred mainly during the last week, and some cannibalism occurred among cuttlefish fed artificial diets. Finally, lipid composition of diets, DG and mantle of each group were analysed. Sardine diet was characterized by high levels of triacylglycerol (TG), whereas the main difference between shrimp and crayfish was the higher n‐3/n‐6 ratio found in shrimp. Changes in the lipid composition of DG were related to diet, but did not correlate with growth data. A strong loss of TG in the DG of artificial diets groups was notable. No differences in mantle lipid composition among the natural diets were found, but artificial diet groups showed higher contents of neutral lipids in their mantle respect to natural diets. According to results obtained, crayfish (P. clarkii) could be used as an alternative prey for rearing S. officinalis compared with shrimp. Artificial diets showed the worst effects in growth and mortality as well as the stronger influence on DG and mantle lipid composition of cuttlefish.  相似文献   

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