首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
This study was carried out to evaluate the effects of dietary supplementation of thermotolerant bacterium on growth and immune responses of Nile tilapia (Oreochromis niloticus). Bacillus paralicheniformis SO‐1 was isolated from marine environments and incorporated into four isonitrogenous (300g/kg crude protein; cp) and isocaloric (18 MJ/kg) diets at four concentrations: 0, 5, 10 and 20 g/kg diet. Each diet was fed to triplicate groups of Nile tilapia (41.5 ± 0.5 g average weight) at a daily rate of 3% of their biomass, three times a day for 50 days. At the end of the feeding trial, the growth rates, feed utilization efficiency (feed conversion ratio, protein efficiency ratio, protein productive value), digestive enzymes (protease, amylase and lipase) activities, immunological response (serum lysozyme activity, phagocytic activity, respiratory burst and superoxide dismutase activity) and the expression of immune‐related genes [interleukin‐1 (IL‐1), interleukin‐4 (IL‐4) and interleukin‐12 (IL‐12)] were determined. Growth rates, digestive enzymes activities and immunological parameters were significantly improved (p < 0.05) with increasing supplemental SO‐1 up to 10 g/kg. However, further increase in bacterial concentration to 20 g/kg lead to significant decline in fish performance and immune response (p < 0.05). The expression of IL‐1, IL‐4 and IL‐12 genes was significantly up‐regulated (p < 0.05) in the liver of Nile tilapia fed SO‐1‐treated diets. This study clearly demonstrated that B. paralicheniformis SO‐1 could be considered as an efficient growth promoter and immune‐stimulating probiotic for farmed Nile tilapia.  相似文献   

2.
The objective of this study was to evaluate the effect of dietary addition of the essential oil from Lippia alba (EOLA) on growth performance, biochemical and haematological variables and survival after Aeromonas spp. infection of Nile tilapia juveniles (Oreochromis niloticus). Five diets were evaluated with increasing levels of EOLA (0.0 control; 0.25; 0.50; 1.0; and 2.0 ml/kg diet). After 45 days of feeding, the fish were infected with Aeromonas spp. followed by a 14‐day period of observation. There was no mortality during growth assessment. The addition of 2.0 ml EOLA/kg diet improved feed conversion ratio and condition factor and increased lysozyme activity and haematocrit (Hct), and decreased plasma globulin levels compared to the control group. The survival of fish infected with Aeromonas spp. was higher in those fed with 2.0 ml EOLA/kg diet than in fish fed with 0.0–0.5 ml EOLA/kg diet. We concluded that the inclusion of 2.0 ml EOLA/kg diet is recommended for Nile tilapia juveniles, because it improved feed conversion, Hct and immunological activity, did not provoke metabolic changes, and increased survival after Aeromonas spp. infection.  相似文献   

3.
This research studied the in vitro compatibility of Cherax quadricarinatus digestive proteases and crude enzyme extracts recovered from fish‐processing waste to evaluate their potential use as feed additives to increase digestion efficiency in decapod crustaceans. The sources of exogenous enzymes were: Pleoticus muelleri (Pm), Artemesia longinaris (Al), and Illex argentinus (Ia). The midgut glands of early (7.2 ± 0.34 g) and advanced juveniles (13.8 ± 1.49 g) of C. quadricarinatus were used for all the assays. The compatibility and synergy between crayfish and exogenous enzymes were evaluated through sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) electrophoresis and the hydrolysis of azocasein and four different meals. SDS–PAGE gels demonstrated that crayfish bands remained active when their enzymes were combined with the enzymes from Pm and Ia. An apparent enzymatic synergism was found when Pm and crayfish proteases were incubated together at pH 6 and 8 with azocasein (p ? 0.05). The ability to hydrolyze the different feed ingredients varied among the enzyme combinations assayed. Our findings suggest that fish waste has potential as a source of proteases, adding value to these processing residues and promoting a zero‐waste industry. Enzymes obtained from Pm and Ia are suitable to be used as food additives for crayfish. The results should be validated through feeding trials.  相似文献   

4.
In vitro assays used porcine or bovine trypsin as models of exogenous enzymes to determine functioning in the presence of enzymatic extracts from the digestive gland of whiteleg shrimp Penaeus vannamei. Using electrophoresis and zymograms, when enzymes from the shrimp were mixed in the absence of protein substrate, they hydrolysed the trypsin from bovine or porcine origin. Porcine or bovine trypsin, when mixed with shrimp enzymes in pH‐stat assays in the presence of shrimp commercial feed, fish meal, or casein, there was added activity to hydrolyse the protein substrate. Hydrolysis of protein substrate was twofold to threefold stronger if exogenous enzymes were added. Results suggest that porcine or bovine trypsin could be used as feed supplements for whiteleg shrimp P. vannamei to enhance hydrolysis of proteins in feeds, because the commercial enzymes contributed to the hydrolysis of the protein in the three substrates in the presence of shrimp enzymes.  相似文献   

5.
This study assessed the immune response of Nile tilapia (Oreochromis niloticus L.) after feeding on different levels (0.1%, 0.2% and 0.4%) of dietary Indian lotus (Nelumbo nucifera) leaf powder for 45 days. We evaluated both the nonspecific immune response at the end of the feeding period and the resistance to Aeromonas hydrophila. Exposure to Indian lotus resulted in a significant elevation in serum total globulins, serum lysozyme activity, serum killing percentage and the phagocytic activity (p < 0.05). Total serum protein and albumin showed no remarkable variation between tilapia fed on 0.1% Indian lotus and the control group (p > 0.05). In addition, the relative expressions of immune‐related genes, namely interleukin–1β and tumour necrosis factor–α were significantly up‐regulated in tilapia fed on 0.4% Indian lotus as compared to the control group; their expressions were down‐regulated in the other tested groups (p < 0.05). The survival rate of Nile tilapia postchallenge to A. hydrophila reported a significant and dose‐dependent increase in the Indian lotus‐supplemented groups (p < 0.05). Therefore, dietary incorporation of Indian lotus leaves (0.4%, 0.2% and 0.1%) could strengthen the immunity of Nile tilapia and improve its resistance to A. hydrophila infection. Therefore, Indian lotus leaves could serve as potential feed supplements for Nile tilapia.  相似文献   

6.
A 3 × 2 factorial experiment was designed to evaluate the effect of different ratios of fish meal (FM): sunflower meal (SFM) with or without exogenous xylanase supplementation on growth, feed utilization, digestive enzymes activities, apparent digestibility, intestinal and liver morphology and chemical composition of Nile tilapia, Oreochromis niloticus. Three isonitrogenous (329.80 g/kg of crude protein) and isoenergetic (18.46 MJ/kg gross energy) experimental diets were formulated as SFM1 (FM:SFM = 2:1), SFM2 (FM:SFM = 1:1) and SFM3 (FM:SFM = 1:2) based on protein content. Each diet was supplemented with 0 or 0.5 g/kg of exogenous xylanase and was fed to triplicate groups of twelve fish (with initial weight, 1.31 ± 0.02 g) for 84 days. After 84 days of feeding period, the highest weight gain, specific growth rate, protein efficiency, protein productive value and the best feed conversion ratio were recorded in fish fed either SFM1 or SFM2 supplemented with exogenous xylanase. Whereas lowest growth performance was recorded in fish fed SFM2 and SFM3 un‐supplemented with xylanase. The highest activities of chymotrypsin, trypsin, lipase, amylase, alkaline phosphatase and cholecystokinin were observed in fish fed SFM1 and SFM2 diets supplemented with xylanase. The highest ADCs of dry matter, protein, lipid and digestible energy were recorded in fish fed SFM1 and SFM2 diets supplemented with exogenous xylanase. Supplementation of exogenous xylanase improved muscularis mucosa thickness, height of mucosal folds and enterocytes of intestinal fish. Addition of exogenous xylanase increased the calcium and phosphorus retention. Results of this study indicated that the addition of exogenous xylanase to diet containing high inclusion level of sunflower meal improved growth, digestive enzymes, nutrient digestibility, histological morphometric of liver and intestine and nutrient retention.  相似文献   

7.
A 4 × 3 factorial study was conducted to evaluate the effect of four experimental diets (a control diet and a 0, 50, and 100% fish meal replacement diet) and the period of time Nile tilapia, Oreochromis niloticus, were fed those diets (0, 20, and 40 days) on the alkaline proteolytic activity of the animals’ digestive tract, as well as their potential interaction. Significant differences (at P < 0.05) and a significant interaction were observed among dietary treatments for the alkaline proteolytic activity of tilapia after 40 days of feeding. This study confirmed that, under these experimental conditions, a 50% fish meal replacement formulation elicited the highest alkaline proteolytic activity in the digestive tract of tilapia, which resulted in the highest final weight and specific growth rate (SGR), but further research is needed to establish the relative contribution of the alkaline proteases to the overall proteolytic activity of this omnivorous fish species.  相似文献   

8.
A nutrition trial was conducted to investigate the effects of dietary lipid levels and supplemental Ulva meal on growth performance, feed efficiency, nutrient utilization, and body composition of juvenile Nile tilapia, Oreochromis niloticus. Four isonitrogenous (CP 40%) diets containing 0% and 5% Ulva meal were formulated to contain 10% (low-lipid; LL) and 20% (high-lipid; HL) crude lipid. Triplicate groups of fish (~10 g) were fed to apparent satiation three times daily for 16 weeks. Fish fed 5% Ulva meal showed an increased growth performance (P < 0.05) compared with fish fed non-Ulva supplemented diets, irrespective of dietary lipid level. In particular, the incorporation of Ulva meal improved specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). Feeding fish 5% Ulva meal diets resulted in significantly lower carcass lipid content. The results indicate that 5% inclusion of Ulva meal at both dietary lipid levels improves growth performance, feed efficiency, nutrient utilization, and body composition of Nile tilapia.  相似文献   

9.
Aquaculture development in Ghana is currently limited by inadequate supply of fingerlings and prohibitive cost of commercial feeds among other challenges. This study tested the feasibility of using low‐cost feeds containing soybean meal instead of fishmeal for nursing Nile tilapia (Oreochromis niloticus) fry. Three isonitrogenous (~48% crude protein) and isoenergetic (~17 kJ/g) diets with increasing inclusions of soybean meal as partial replacements for fishmeal were formulated. A commercial fishmeal‐based fry feed served as the control diet. Triplicate groups of 225 fish per tank (average initial weight: 2.09 ± 0.14 g) were stocked in a recirculating aquaculture system and fed the experimental diets for 21 days. Afterwards, we investigated the postprandial metabolism, nutrient digestibility, growth and gut histology in Nile tilapia fry. Simple economic analyses were also conducted to assess the cost‐effectiveness of the diets used in the feed trial. The dietary inclusions of the soybean meal significantly reduced feed cost by ~43% relative to the control diet. The growth performance and feed utilization parameters did not vary significantly among the different treatments. The soybean diets elicited significant reductions in villi heights and goblet cell numbers, which corresponded with increasing dietary levels of soybean meal. This study confirms the potential of soybean meal as a partial replacement for fishmeal in Nile tilapia fry diets in terms of lower feed costs, fish growth performance, nutrient digestibility and postprandial nitrogenous excretions. The inclusion of soybean, however, affected negatively the gut integrity of the fry.  相似文献   

10.
This study was conducted to evaluate the effect that feeding on differently treated soybean meals may have on digestive protease activity of the Nile tilapia (Oreochromis niloticus). Untreated full fat soybean (USB), heated fullfat soybean (HSB), soaked fullfat soybean (SSB) and commercial defatted soybean meal (DSB) totally replaced fish meal (FM) in test diets (30% crude protein) fed to fish juveniles (mixed sexes) for 30 days. After this period, total activity of digestive proteases was determined in each group and the ability of such proteases to hydrolyse the different protein sources and formulated feeds was tested in vitro. Significant differences were observed between treatments, with lower values obtained for fish fed on USB, suggesting a modification in the composition of secreted proteases. In addition, an inhibitory effect produced by wheat bran included in the test diets on protease activity of fish was also shown. The usefulness of using in vitro assays for a preliminary assessment of the nutritive value of aquafeed ingredients is discussed.  相似文献   

11.
The present study investigated the effects of argan oil, obtained from Argania spinosa, on pre‐ and post‐challenge immuno‐haematological and biochemical responses of Nile tilapia, Oreochromis niloticus. For this purpose, the fish were fed diets containing 0, 0.5%, 1% or 2% argan oil for 45 days. Following 45 days of feeding, fish were challenged with Lactococcus garvieae and mortality was recorded for 15 days. During the pre‐challenge period, significantly higher respiratory burst activity, total white blood cell (WBC), serum lysozyme activity and myeloperoxidase activity were determined in the argan oil‐fed groups. The serum glucose and cholesterol levels decreased whilst total protein and albumin did not change in the groups fed with argan oil‐supplemented diets. After challenge with Lactococcus garvieae, the percentage survival (%) was found to be the highest in the 1% and 2% argan oil‐supplemented feeding groups. Also, there was a significant increase in weight gain, specific growth rate and feed conversion ratio in those fish fed argan oil. The results of this study indicated that after the supplementation of fish diets with argan oil, especially at 1% and 2% concentrations, the immunological, haematological and biochemical values remained similar in both the pre‐ and post‐challenge periods and the immune response against L. garvieae in Nile tilapia was modulated.  相似文献   

12.
Nile tilapia (Oreochromis niloticus) is currently one of the most farmed freshwater fish and contributes significantly to total global aquaculture production. The genetically improved strain of O. niloticus (GIFT) was introduced to Papua New Guinea (PNG) in 1999 to improve food and income security. The high cost and low availability of commercial fish feed hinder the growth of GIFT farming in PNG. Stable carbon and nitrogen isotopes were used to determine the role of supplementary and natural food sources in the diet of GIFT in pond‐based aquaculture. Two treatments were used: treatment 1 was daily feeding, and treatment 2 was weekly feeding, each with three replicates. Isotopic analysis of muscle tissue and all potential food sources showed that pellet feed contributed 7% to the growth of GIFT in daily‐fed ponds and 33% in the weekly‐fed ponds. Highly enriched δ15N values for chicken manure, compared to depleted values for GIFT and other natural food sources in both treatments, clearly indicate insignificant contributions of this input to production. After 90 days of cultivation, the average final body weight of GIFT receiving daily feed inputs was 134 g (average 19 cm), while for weekly‐fed it was 92 g (17 cm). The feed conversion ratio (FCR) was poor (6.4:1) in the daily‐fed GIFT ponds compared to a better, and preferable, FCR (1:1) in the weekly‐fed ponds. The findings of this study show that pelleted feed was not the major contributor to the growth of GIFT. Genetically improved farmed tilapia aquaculture should focus on enhancing natural food availability for fish production.  相似文献   

13.
Immunostimulatory feed supplements have an increasingly interest in aquaculture management. Generally, an individual supplement was used in fish diets but it is expected that the use of multi‐supplements may show synergistic enhancements in fish performance, health, and immunity. Therefore, the present investigation was carried out to evaluate the use of dietary probiotic Lactobacillus plantarum and whey protein concentrate (WPC) in practical diets for Nile tilapia, Oreochromis niloticus. Hence, probiotic L. plantarum, WPC and their mixture were incorporated into a basal fish diet (300 g/kg crude protein) as follows: T1 = a basal control diet, T2 = a basal diet containing L. plantarum, T3 = a basal diet containing 1.0 g WCP/kg diet and T4, T5 or T6 = basal diets containing probiotic L. plantarum + 1.0, 2.0 or 3.0 g WCP/kg diet, respectively. Fish (15.2 ± 0.6 g) were fed on one of the tested diets up to apparent satiation twice a day for 60 days. After that, fish were intraperitoneally injected with pathogenic bacteria Aeromonas sobria and fish mortality was observed for 10 days postchallenge. Fish growth and feed intake were significantly improved by dietary probiotic L. plantarum (T2) and/or WPC (T3) over the control group (T1), and highest fish performance was observed in T5–T6 fish groups. Similarly, highest values of haematocrit, glucose, total proteins, albumin, and globulin were significantly observed in T5–T6 fish groups. Likewise, fish fed dietary probiotic L. plantarum (T2), WPC (T3), and their mixture (T4–T6) showed antioxidants and immune‐stimulating activities better than the control group. Fish fed the control diet were more susceptible to A. sobria infection showing highest fish mortality (75.0%). Meanwhile, dietary probiotic L. plantarum (T2), WPC (T3), and their mixture (T4–T6) enhanced significantly the fish resistance to A. sobria infection resulting in maximum values of relative percent of fish survival (73.3%–80.0%) in T5–T6 groups. The present investigation recommended the use of probiotic L. plantarum with 2.0 g WPC/kg diet to improve the growth, antioxidant, immunity responses and tolerance of Nile tilapia to A. sobria infection.  相似文献   

14.
The feeding experiment was conducted to evaluate the replacement effect of cystine on methionine at a constant total sulphur amino acid (TSAA) level in practical diets of juvenile Nile tilapia (Oreochromis niloticus). Soybean meal, cottonseed meal and rapeseed meal were used as the main protein sources in the diets containing 16.4 MJ kg?1 gross energy and 301 g kg?1 crude protein. Crystalline DL‐methionine (Met) to L‐cystine (Cys) were supplemented to fulfil various ratios of Met to Cys (60:40, 50:50, 40:60 and 30:70, based on an equimolar sulphur basis; and the analysed ratios were 53:47, 49:51, 34:66 and 31:69). Each diet was fed to triplicate groups of Nile tilapia juveniles (10.1 g mean initial weight) in a recirculation system for 8 weeks. The results showed that the growth performance and nutrient accretion were not affected by dietary methionine:cystine ratios (P > 0.05). However, the survival rates of fish tended to decrease with the decreasing methionine: cystine ratios. The only dietary treatment to achieve 100% survival was the 53:47 methionine: cystine treatment. And methionine digestibility decreased linearly with the decreasing methionine: cystine ratios (P < 0.05). Thus, it was concluded that cystine could replace up to approximately 47% of TSAA requirement on an equimolar sulphur basis without hampering growth performance in the practical diets of juvenile Nile tilapia.  相似文献   

15.
Nile tilapia juveniles (8.35 ± 0.80 g) were fed on four levels (0.0%; 0.5%; 1.0%; 2.0%, 4.0%) of Aurantiochytrium sp. meal (ALL‐G‐RICH?), a source of docosahexaenoic acid (DHA). The 1% Aurantiochytrium sp. meal diet was compared to a control diet, which contained the same amount of DHA as cod liver oil (CLO) at 1.7% diet. Groups of 25 fish were stocked in 100 L tanks and fed twice daily until apparent satiation, for 57 days, at 28°C. Increasing dietary Aurantiochytrium sp. meal reduced the body retention of DHA and n‐3 polyunsaturated fatty acids (n‐3 PUFA) but increased the body retention of alpha‐linolenic (α‐LNA), linoleic (LOA) and n‐6 polyunsaturated fatty acids (n‐6 PUFA). Fatty acid profile in tilapia muscle was affected by increasing dietary inclusions of Aurantiochytrium sp. meal, with an increase in DHA, α‐LNA, n‐3 PUFA and n‐3 long chain‐polyunsaturated fatty acids (n‐3 LC‐PUFA) but a decrease in monounsaturated fatty acids (MUFA), n‐6 PUFA and n‐6 long‐chain polyunsaturated fatty acids (n‐6 LC‐PUFA). There was a larger body retention of DHA, α‐LNA, LOA, n‐3 PUFA and n‐6 PUFA fatty acids and a higher percentage of DHA, n‐3 PUFA and n‐3 LC‐PUFA in muscle fatty acid profile in fish fed on CLO diets than in those fed on 1% Aurantiochytrium sp. Therefore, Aurantiochytrium sp. meal is an alternative source of DHA for Nile tilapia diets.  相似文献   

16.
Nile tilapia (Oreochromis niloticus) juveniles were fed diets containing 13 g/kg total polyunsaturated fatty acids (PUFAs) at different n‐3/n‐6 dietary ratios (0.2, 0.5, 0.8, 1.3 and 2.9) for 56 days, at 28°C. Subsequently, fish were submitted to a winter‐onset simulation (22°C) for 33 days. PUFA n‐3/n‐6 dietary ratios did not affect fish growth at either temperature. At 28°C, tilapia body fat composition increased with decreasing dietary PUFA n‐3/n‐6. Winter‐onset simulation significantly changed feed intake. The lowest dietary n‐3/n‐6 ratio resulted in the highest feed intake. At both temperatures, body concentrations of α‐linolenic acid, docosahexaenoic acid, eicosatrienoic acid and docosapentaenoic acid decreased as dietary n‐3/n‐6 decreased. Body concentrations of eicosapentaenoic acid (EPA, 20:5 n‐3) increased with decreasing concentrations of dietary EPA. The n‐6 fatty acids with the highest concentrations in tilapia bodies were linoleic acid and arachidonic acid (ARA, 20:4 n‐6). At 28°C, SREBP1 gene expression was upregulated in tilapia fed the lowest n‐3/n‐6 diet compared to tilapia fed the highest n‐3/n‐6 ratio diet. Our results demonstrate that a dietary PUFA of 13 g/kg, regardless of the n‐3/n‐6 ratio, can promote weight gains of 2.65 g/fish per day at 28°C and 2.35 g/fish per day at 22°C.  相似文献   

17.
Edwardsiella ictaluri infects several fish species and protection of the all the susceptible fish hosts from the pathogen using a monovalent vaccine is impossible because the species is composed of host-based genotypes that are genetic, serological and antigenic heterogenous. Here, immunoinformatic approach was employed to design a cross-immunogenic chimeric EiCh protein containing multi-epitopes. The chimeric EiCh protein is composed of 11 B-cell epitopes and 7 major histocompatibility complex class II epitopes identified from E. ictaluri immunogenic proteins previously reported. The 49.32 kDa recombinant EiCh protein was expressed in vitro in Escherichia coli BL-21 (DE3) after which inclusion bodies were successfully solubilized and refolded. Ab initio protein modelling revealed secondary and tertiary structures. Secondary structure was confirmed by circular dichroism spectroscopy. Antigenicity of the chimeric EiCh protein was exhibited by strong reactivity with serum from striped catfish and Nile tilapia experimentally infected with E. ictaluri. Furthermore, immunogenicity of the chimeric EiCh protein was investigated in vivo in Nile tilapia juveniles and it was found that the protein could strongly induce production of specific antibodies conferring agglutination activity and partially protected Nile tilapia juveniles with a relative survival percentage (RPS) of 42%. This study explored immunoinformatics as reverse vaccinology approach in vaccine design for aquaculture to manage E. ictaluri infections.  相似文献   

18.
The present study was conducted to administer a commercial multi‐strain probiotic (MP), Yilibao (Bacillus velezensis:Bacillus cereus:Lactobacillus casei = 2:2:1), in Nile tilapia, Oreochromis niloticus. In terms of aerobic Bacillus spp. counts, we produced five diets containing 0, 0.34, 1.68, 3.36 and 6.72 g/kg of MP dry product (Control, T1, T2, T3, T4). Seven hundred and fifty tilapia juveniles (13.26 ± 0.01 g) distributed into 25 tanks in five replications were fed their diet for eight weeks. Results showed that fish fed T3 and T4 diets displayed significantly higher final body weight and weight gain (p < .05). Further, all MP‐treated fish exhibited remarkably decreased plasma lipid profiles (cholesterol, triglycerides) (p < .05) and fish fed T3 and T4 diets displayed significantly higher plasma myeloperoxidase activity and complement C3 content (p < .05). Additionally, fish fed T3 and T4 diets exhibited significantly promoted total antioxidant capacity, glutathione peroxidase activity, glutathione level and declined malondialdehyde content in the plasma and/or liver (p < .05). Moreover, significantly elevated chymotrypsin activity, villus height and intraepithelial lymphocytes counts were found in fish fed T3 and T4 diets (p < .05). As fish fed T3 and T4 diets surpassed the other treatments in growth, immune–antioxidative status and gut health, the recommended dose for tilapia is 3.36–6.72 g/kg.  相似文献   

19.
The objective of this study was to evaluate growth, body chemical composition and lipid profile of Nile tilapia juvenile fed with Schizochytrium sp. Two hundred and forty Nile tilapia (Oreochromis niloticus) juvenile (1.33 ± 0.11 g) were distributed in 20 aquariums, at the density of 12 fish per aquarium. The juvenile were fed with five levels of Schizochytrium sp.: Control (0 g/kg of Schizochytrium sp. in feed); AS10 (10 g/kg of Schizochytrium sp. in feed); AS20 (20 g/kg of Schizochytrium sp. in feed); AS30 (30 g/kg of Schizochytrium sp. in feed) and AS40 (40 g/kg of Schizochytrium sp. in feed). The inclusion of Schizochytrium sp. increase the body weight, weight gain, final biomass and biomass gain of tilapia juvenile. The body crude protein of tilapia was increased after addition of microalgae. Juvenile lipid profile also was influenced when fed with 40 g of Schizochytrium sp. per kg and have it levels of omega‐3 and docosahexaenoic acid (DHA) increased, and omega 6:3 ratio decreased. Tilapia juvenile fed with Schizochytrium sp. per kg have better growth, omega‐3 and DHA levels rising in the body, being a considerable source of fatty acids for human nutrition. Levels above 20 g of Schizochytrium sp. per kg in the feed favour the increase of protein in Nile tilapia body.  相似文献   

20.
In this study, the use of Lactobacillus acidophilus as a probiotic for Nile tilapia (Oreochromis niloticus) culture was studied. Fish survival and the expression of some genes involved in the immune response were assessed. Diet supplementation with L. acidophilus for 15 days caused a significant increase in fish survival during a challenge with Aeromonas hydrophila and variations in immune response related to IL‐1β and transferrin expression in Nile tilapia spleen and kidney. Moreover, extracellular products (ECPs) of L. acidophilus showed high antibacterial activity against fish pathogens such as A. hydrophila and Streptococcus agalactiae in vitro. It was also observed that viable L. acidophilus was able to disrupt quorum sensing activity in Chromobacterium violaceum.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号