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1.
An 80‐day feeding trial was conducted to evaluate the influence of different short‐term fasting and re‐feeding strategies on growth and physiological responses in yellowfin seabream, Acanthopagrus latus (2.4 ± 0.2 g) fingerlings. The fish were subjected to four different feeding regimes, and the control group fed four times daily to apparent satiation throughout the whole feeding period, while the other three groups were deprived for 2, 4 and 8 days followed by 8, 16 or 32 days of re‐feeding (F2R8, F4R16 and F8R32, respectively) in repeated cycles for 80 days. The fish in the control and F2R8 groups had the highest and the lowest total length, respectively (p < .05). Moreover, fish exposed to F4R16 had the highest hepatosomatic indices, while control fish had the lowest hepatosomatic indices (p < .05). Fish in the F2R8 group relatively had higher catalase and glutathione‐S‐transferase activities than other groups (p < .05). Furthermore, total protease, α‐amylase and alkaline phosphatase activities in the F4R16 and F8R32 were higher than the F2R4 and control groups (p < .05). Overall, this study showed that compensatory growth in weight and length and digestive enzyme activities were observed in the F4R16 and F8R32; however, the increase in the activity of antioxidant enzymes in the F8R32 group indicated that oxidative stress remained after 80 days of re‐feeding in the liver.  相似文献   

2.
In this study, we used artificial insemination to generate hybrid groups of fish [MC‐F1(MA♀×CA♂) and MC‐F2(MC‐F1♀×♂)] by intergeneric crosses of Megalobrama amblycephala (MA) and Culter alburnus (CA); sequential backcrosses [CAM‐B1 (CA♀×MC‐F1♂) and MCC‐B1 (MC‐F1♀×CA♂)] were also performed. All these hybrids showed high rates of fertilization, hatching and survival (p > 0.05). For genetic traits, compared with those of the M. amblycephala and C. alburnus parental lines (Table 1), the fertilization rate, hatching rate and 7‐day survival rate of MC‐F1(MA♀×CA♂), MC‐F2(MC‐F1♀×♂), CAM‐B1 (CA♀×MC‐F1♂) and MCC‐B1 (MC‐F1♀×CA♂) by artificial insemination exhibited similar high rates (p > 0.05). The morphology of the four hybrids MC‐F1/F2, CAM‐B1 and MCC‐B1 were intermediate between those of their parents. Compared with their parents of MA and CA, weight gain rate (WG), specific growth rate (SGR) and protein efficiency ratio (PER) of hybrids MC‐F1/F2, CAM‐B1 and MCC‐B1 were significantly (p < 0.05) increased and feed conversion ratio (FCR) was significantly (p < 0.05) decreased after 3 months feeding. Moreover, protein content of muscle for MC‐F1/F2, CAM‐B1 and MCC‐B1 was significantly (p < 0.05) higher and carbohydrate content of muscle was significantly (p < 0.05) lower than their parents. The females and males of the four hybrids had normal gonadal development. In this study, we successfully generated intergeneric and backcross hybridization lines with fertile potential among fish of the Cultrinae subfamily and these hybrids had obvious heterosis in terms of growth performance, feed utilization and muscle quality.  相似文献   

3.
We studied the effect of strain and selection lines on the fecundity of the cyclopoid copepod Paracyclopina nana. We used six strains (HL, YL, BS, SL, TH, TS) and six isofemale lines (including three higher and three lower fecundity lines). As for the selection of strain, total nauplii production per female of SL strain was the highest in the individual culture (231 nauplii per female) and population growth rate in HL and SL strains showed higher values than the others in combined culture. For the selection of line, the total nauplii production per female of HF2‐2 (high fecundity and second generation) line was the highest (302 nauplii per female) but those of LF2‐1 (low fecundity) (80 nauplii per female), and LF2‐3 (46 nauplii per female) lines were lower than the others. In F4 generation, three selected HF2‐2 line showed that the total nauplii production were higher than those of three selected LF2‐3 lines. In the combined culture on the different selection lines (F8), population growth rate of two selected high fecundity lines showed higher values than that of the non‐selection group and selected low fecundity line. Our results demonstrate that the production of P. nana can be improved by selection of the line with high fecundity.  相似文献   

4.
Sixteen candidate disease‐resistant parameters were selected through which to evaluate the acute hepatopancreatic necrosis disease (AHPND)‐resistant capability of Exopalaemon carinicauda after three generations of selection for AHPND‐causing strain of Vibrio parahaemolyticus (VPAHPND) resistance in our previous study. However, these parameters required further verification. In this study, another AHPND‐resistant E. carinicauda series was obtained through a short‐term selection procedure, consisting of three virulent challenge rounds of selection (about three‐week interval for each challenge) with VPAHPND infection. After this selection, the survival rate at 144 hr post infection (hpi) increased from 23.33% to 37.78% and the observed 48‐hr LD50 of VPAHPND to shrimp increased from 105.5 cfu/ml to 106.5 cfu/ml. Then, the immune response of this AHPND‐resistant E. carinicauda was studied using the 16 candidate AHPND‐resistant parameters selected for in our previous study. The improved VPAHPND clearance rate in hpi, increased total haemocyte counts, haemocyanin concentration, alkaline phosphatase activity and expressions of six immune‐related genes (Tollip and ALF in haemocytes and hepatopancreas; lysozyme, crustin and cathepsin B in hepatopancreas; and LGBP in haemocytes) at 24 hpi after the three‐round challenge selection suggest that these immune parameters may be reliable markers for the evaluation of the physiological status and potential AHPND‐resistant phenotypes in E. carinicauda.  相似文献   

5.
Aeromonas hydrophila is known to be causative agent of an infection named as Bacterial haemorrhagic septicaemia or red pest in freshwater fish. The aim of this study was to develop and validate the glycoprotein‐based fish vaccine against Aeromonas hydrophila. For this aim, after identification and characterization of A. hydrophila isolates from fish farms, one A. hydrophila isolate was selected as vaccine strain. Antigenic glycoproteins of this vaccine strain were determined by Western blotting and glycan detection kit. The connection types of these glycoproteins were examined by glycoprotein differentiation kit. Two glycoproteins, molecular weights of 19 and 38 kDa, with SNA connection type were selected for use in vaccination trials. After their purification by SNA‐specific lectin and size‐exclusion chromatography, protection studies with purified proteins were performed. For challenge trials, four experimental fish groups were designated: Group I (with montanide), Group II (with montanide and ginseng), Group III [with Al(OH)3] and Group IV [with Al(OH)3 and ginseng]. The survival ratings of fish were determined, and protection was calculated as 21.56%, 29.41%, 69.83% and 78.88% in groups I, II, III and IV, respectively. In conclusion, A. hydrophila glycoproteins with Al(OH)3 and ginseng could be used as a safe and effective vaccine for fish.  相似文献   

6.
This study was intended to evaluate tannin mediated inhibition of digestive proteases in two different size groups (fingerlings, F, 4.5 ± 0.7 cm; advanced fingerlings, AF, 18.2 ± 1.6 cm) of rohu, Labeo rohita. Graded levels (50, 100, 150 and 200 nM) of tannin (Gallotannin, 99% purity) were added to the enzyme extracts (30°C, 1 hr) prior to determination of enzyme activities. Changes in the activity of trypsin, chymotrypsin and total protease in relation to the control sets were determined through biochemical assay of enzymes and SDS‐PAGE zymography. The study revealed that tannin significantly inhibited trypsin, chymotrypsin and total protease activities in a dose dependent manner as evident from the regression equations. The degree of the inhibition appeared to be significantly higher for the F in contrast to the AF (F5,66 = 282.311; p < 0.0001). Trypsin activities were reduced by 8.04 ± 0.19% to 52.68 ± 0.72% and 5.61 ± 0.22% to 39.46 ± 0.19% in F and AF, respectively. The reduction in Chymotrypsin activities ranged between 16.11 ± 0.03% to 38.02 ± 0.27% in F and 6.31 ± 0.07% to 22.80 ± 0.32% in AF. Total protease activities were reduced by 10.9 ± 0.07% to 49.60 ± 0.32% in L. rohitaF, whereas, it ranged between 5.19 ± 0.06% to 32.60 ± 0.13% in AF. On a comparative scale, the difference in tannin induced inhibition in F and AF were more prominent for trypsin and chymotrypsin than total protease. Further, nine protease activity bands (15.9–69 kD) with different electromobility were noticed in both the size groups. Subsequent densitometry analysis revealed that the average densities of the protease activity bands were gradually decreased with increasing level of tannin exposure (50–200 nM). The study might indicate adaptive tolerance to tannin in larger size groups and emphasizes the need for removal of tannin in the plant feedstuffs, especially for feeding the fingerlings of L. rohita.  相似文献   

7.
Flavobacterium psychrophilum, the causative agent of bacterial cold‐water disease (BCWD) in freshwater‐reared salmonids, is also a common commensal organism of healthy fish. The virulence potential of F. psychrophilum isolates obtained from BCWD cases in Ontario between 1994 and 2009 was evaluated. In preliminary infection trials of rainbow trout juveniles, significant differences (0% to 63% mortality) in the virulence of the 22 isolates tested were noted following intraperitoneal injection with 108 cfu/fish. A highly virulent strain, FPG 101, was selected for further study. When fish were injected intraperitoneally with a 106, 107 or 108 cfu/fish of F. psychrophilum FPG 101, the 108 cfu/fish dose produced significantly greater mortality (p < 0.05). The bacterial load in spleen samples collected from fish every 3 days after infection was determined using rpoC quantitative polymerase chain reaction amplification and by plate counting. Bacterial culture and rpoC qPCR were highly correlated (R2 = 0.92); however, culture was more sensitive than the qPCR assay for the detection of F. psychrophilum in spleen tissue. Ninety‐seven per cent of the asymptomatic and the morbid fish had splenic bacterial loads of <2.8 log10 gene/copies and >3.0 log10 gene copies/reaction, respectively, following infection with 108 cfu/fish.  相似文献   

8.
Genetic parameters and response to selection were estimated for the harvest body weight of Litopenaeus vannamei. The data consisted of 24 072 progeny from 178 sires and 171 dams in two generations (G0 and G1) with a nested mating structure. All families were randomly divided into two groups and then cultured in two farms at different locations (Huanghua and Qingdao). The heritability estimates from G0 and G1 were 0.278 ± 0.136 and 0.423 ± 0.065 respectively. Over two generations, the heritability estimate was 0.335 ± 0.087, and the common environmental effect was 0.084 ± 0.031. A bivariate animal model was used to estimate variance and covariance components, whereby the body weight in the two farms was treated as a genetically distinct trait. Genetic correlation was close to unity (0.943 ± 0.066), indicating that a genotype by environmental interaction for harvest body weight was small. The response to selection in harvest body weight was estimated using two methods (the realized and predicted responses). The realized response was estimated from the difference in the least squares means of body weight for the selection and control populations. The predicted response was obtained from the difference in the mean estimated breeding values between generations. The realized response was 2.30%, while the predicted responses were 2.00% and 1.37% for within‐ and across‐generation datasets using two sets of genetic parameters respectively. The results would provide crucial information in pacific white shrimp breeding programs in China.  相似文献   

9.
Gonadal recrudescence in Barbus altianalis from River Nile, Jinja (33°05E; 0°45N) Uganda was studied prior to induced spawning. Oocytes in B. altianalis were found to develop in cohorts suggesting batch spawning throughout the year with pronounced spawning activities coinciding with rainfall peaks of April and September. There was a strong positive correlation between rainfall and gonadosomatic index (rS = 0.75, P = 0.008). B. altianalis had low fecundity (6.0 ± 2.0 per gram) and large‐sized eggs (2.97 ± 0.1 mm). Induced spawning was successful with exogenous hormones and water current. Results from this study suggested that total striping may not be appropriate, but larger eggs would confer high survival of offsprings under optimal conditions. The success registered in induced spawning of B. altianalis provides a breakthrough in seed production for multiplication and culture of this economically important fish species.  相似文献   

10.
A 45‐day feeding trial was conducted to study the stress ameliorating and immunomodulatory role of microbial levan in Cyprinus carpio fry exposed to sublethal dose (1/10th LC50) of fipronil [(±)‐5‐amino‐1‐(2,6‐dichloro‐α,α,α‐trifluoro‐p‐tolyl)‐4‐trifluoromethylsulfinylpyrazole‐3‐carbonitrile]. Two hundred and twenty‐five fry were randomly distributed in five treatments in triplicates. Four purified diets were prepared with graded levels of microbial levan. Five different treatment groups were levan control L0P0 (basalfeed + 0% levan without exposure to pesticide); pesticide control L0P1 (basalfeed + 0% levan with exposure to pesticide); L0.25P1 (basalfeed + 0.25% levan with exposure to pesticide); L0.50P1 (basalfeed + 0.50% levan with exposure to pesticide) and L0.75P1 (basalfeed + 0.75% levan with exposure to pesticide). Lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and fructose‐1,6‐diphosphatase (FDPase) activites were significantly (P < 0.05) increased, whereas alkaline phosphatase (ALP), adenosine triphosphatase (ATPase) and acetyl choline esterase (AchE) activities were significantly (P < 0.05) reduced in higher levan‐fed groups. RBC, haemoglobin and WBC counts were significantly (P < 0.05) increased in the levan‐fed groups. Similar trends were also observed for the total serum protein, globulin, NBT and lysozyme activities. Blood glucose and serum cortisol exhibited a third order polynomial relationship with increasing level of dietary levan. Overall result showed stress ameliorating, immunostimulating and protective role of microbial levan against fipronil‐induced stress in C. carpio fry at 0.75% level of dietary levan supplementation.  相似文献   

11.
A 45‐days feeding trial was conducted to study the immunomodulatory effect and interferon gamma gene expression of dietary fucoidan rich seaweed extract (FRSE) from Sargassum wightii on Pangasianodon hypophthalmus fingerlings. One hundred and eighty fingerlings were distributed into six experimental groups in triplicates. Each group was stocked with 10 fish and fed to satiation with iso‐nitrogenous (34.96 ± 0.09–35.18 ± 0.03 CP%) and iso‐caloric (368.65 ± 0.86–375.09 ± 0.26 Kcal/100 g) purified diets containing either 0% FRSE (control), 1% FRSE (TF1), 2% FRSE (TF2), 3% FRSE (TF3), 3% seaweed powder (TS3) or 6% seaweed powder (TS6) in the feed. After feeding trial the experimental fish were challenged with Aeromonas hydrophila. Immunological parameters like respiratory burst activity, lysozyme activity, phagocytic activity and total leukocyte count (TLC) were increased with the increasing level of dietary FRSE, whereas serum Albumin/Globulin (A/G) ratio and blood glucose level exhibited decreasing trend (P < 0.05). Increased TLC, blood glucose level, respiratory burst activity, serum A/G ratio, lysozyme and phagocytic activities were recorded during the post‐challenge period. Maximum expression of interferon gamma (IFN‐γ) gene was recorded in FRSE fed groups than the control group both in pre and post challenge condition. After challenged with A. hydrophila the highest survival was observed in TF2 and TF3 groups whereas lowest survival was observed in the control group. Hence, dietary supplementation of FRSE at an optimum level of 2% reduced the stress and improved the immune status of P. hypophthalmus fingerlings.  相似文献   

12.
Laboratory predation trials were conducted to investigate maximum handling size, prey size and type selection by small (35–37 cm in total length, LT), medium (43–46 cm LT) and larger (58–60 cm LT) snakehead (Channa argus) when feeding on a wide size (9–34 mm in carapace width, CW) range of juvenile Chinese mitten crab (Eriocheir sinensis). The maximum handling size of predator feeding on crabs monotonically increased with predator LT and mouth gape width, GW. Snakehead with at least 16.0 cm LT or 27.7 mm GW would be capability to consume the smallest size group of crabs, whereas the predator with 72.6 cm LT or 63.4 mm GW would be capability to consume all size groups of crabs in these trails. Prey‐size selection trials showed that snakehead has a high preference to the small‐sized crabs, and lower preference to the medium or large size crabs. The preference index was significantly affected by prey size and prey size × predator size interaction, however, was not affected by predator size. In prey type experiments, snakehead consumed lower proportions of juvenile crabs when fed on the crab and crucian carp than when fed on only the crab, which suggests alternative fish prey may reduce predation risk of the crab by snakehead in nature. These results could be useful for improving the fishery management and release strategies for the crab.  相似文献   

13.
A 60‐day indoor growth trial was conducted to study the effects of biofloc on the growth performance of a Penaeus monodon (Fabricius, 1798), water quality and biological indicators including biofloc volume, chlorophyll‐a, heterotrophic bacteria and Bacillus quantity. Two concentrations of sucrose (0 and 75%) were added daily to the P. monodon culture systems (2.94 ± 0.11 g), which were conducted indoors in fibre‐glass tanks (500 L). Results showed that the final body weight and weight gain of the adding 75% sucrose group were significantly higher (P < 0.05) than that of the control, as well as significantly (P < 0.05) improved specific growth rates and survival rates, and reduced feed coefficient. Adding 75% sucrose promoted heterotrophic bacteria, Bacillus and phytoplankton reproduction, and significantly (P < 0.05) reduced the concentration of ammonia‐N (NH4‐N), nitrite‐N (NO2‐N) and nitrate‐N (NO3‐N). The changes of water quality indicators in the two groups showed the similar trend at the end of the experiment, and the ammonia‐N, nitrite‐N, nitrate‐N and phosphate‐P concentrations in the 75% sucrose group were significantly (P < 0.05) lower than those of the control group, Chlorophyll‐a concentrations peaked at 389.12 μg/L in the biofloc sucrose group at 18:00 h, and heterotrophic bacteria peaked 8 h after sucrose was added. The addition of sucrose also reduced the pH of the water. Our research showed that adding sucrose promoted biofloc formation and shortened the formation time; increased the number of heterotrophic bacteria and algae which might play a role in improving water quality by assimilating ammonia‐N and other harmful substances in the water; supplemented food for P monodon growth; and reduced the feed coefficient.  相似文献   

14.
A 7‐week study was conducted to investigate the effect of different fasting and re‐feeding regimes on compensatory growth and some physiological parameters of juvenile Siberian sturgeon (Acipenser baerii). Fish (46.5 ± 0.5 g) were fed on a diet (containing 450 g/kg crude protein and 20 MJ/kg digestible energy) according to four feeding regimes in triplicate including: control group (C, fed everyday), W1 (2 weeks of feeding followed by 1 week of fasting and 4 weeks of re‐feeding), W2 (1 week of feeding followed by 2 weeks of fasting and 4 weeks of re‐feeding) and W3 (3 weeks of fasting followed by 4 weeks of re‐feeding). The fasted groups including W1 (119.6 ± 2.1 g), W2 (118.0 ± 1.7 g) and W3 (108.5 ± 4.8) significantly lost their weights during fasting phase and did not attain the final weight of the C (137.3 ± 1.7 g) after re‐feeding phase. The re‐feeding phase increased the specific growth rate in the fasted groups compared to the C (p < .05). After the fasting phase, concentrations of T3, T4, glucose, total protein and triglyceride in plasma of fasted groups were decreased, but levels of total cholesterol, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase increased compared to the C. After re‐feeding phase, except for glucose level, all mentioned metabolites were restored in the plasma of W1 group, but total protein level and aspartate aminotransferase concentrations in plasma were not restored in W2 and W3 groups. Overall, our finding demonstrated 4 weeks of re‐feeding was too short to induce full compensatory growth in A. baerii juveniles.  相似文献   

15.
To improve release techniques of Japanese flounder, Paralichthys olivaceus, for the purpose of stock enhancement, the substrate preference and burial behaviour over a range of sand grain sizes were investigated under laboratory conditions. Ten 12‐hr trials (i.e. 10 experimental groups), which, respectively, contained two different levels of substrates, demonstrated that juvenile flounder (55–78 mm total length) selected substrate of grain size (GS) < 2.00 mm, and the degree (from high to low) of their preference could be listed as Level 3 (0.50–2.00 mm) > Level 4 (0.25–0.50 mm) > Level 5 (0.05–0.25 mm) > Level 2 (2.00–4.00 mm) > Level 1 (4.00–6.00 mm). The average burying of fish in substrates of GS < 2.00 mm was more than 93.1%. Additionally, along with food deprivation time increased from 12 to 24 hr, some flounder showed random off‐bottom swimming behaviour, and the appearance of off‐bottom swimming behaviour was <3.2%. These results suggest that releasing sites with appropriate substrate grain size (GS < 2.00 mm) are suitable for conducting mass releases of hatchery‐reared flounder juveniles, and starvation prior to release should be minimized. The results of the present study are essential to improve stocking strategies of Japanese flounder and reduce the juvenile mortality after release.  相似文献   

16.
A digestibility trial was conducted with 180 Nile tilapia (32.65 ± 4.52 g) fed a reference diet containing 350 g/kg crude protein and 4,500 kcal/kg gross energy. Five different meat and bone meals (MBMs) were evaluated. The test diets compound by 70% of reference diet and 30% of each MBM were elaborated and classified according to ash content: MBM‐430, MBM‐400, MBM‐370, MBM‐340 and MBM‐310. The apparent availability coefficient (AAC) of minerals and the apparent digestibility coefficient (ADC) of dry matter (DM) were subjected to one‐way analysis of variance (p < .05). Differences among ADC and AAC were determined by Tukey's multiple range test (p < .05). When appropriate, a polynomial regression analysis was performed. Linear correlation analyses between MBM chemical composition and the AAC and ADC were performed (p < .01). Higher values of ADCDM, AACCa and AACP were observed in MBM‐310, while low values were observed in MBM‐430. Quadratic effects of ash, P and Ca contents on AACCa, AACP and ADCDM were observed. The AACCa, AACP and ADCDM indicated a negative correlation with ash, P and Ca contents. MBM‐310 exhibited the highest mineral AAC, which could be used as a mineral source for Nile tilapia.  相似文献   

17.
This study investigated the effects of n‐3 high unsaturated fatty acid (n‐3HUFA) levels on the growth performance, antioxidant enzyme activities and fatty acid profiles of both subadult and adult Litopenaeus vannamei (L. vannamei). Seven iso‐nitrogenous and iso‐lipidic diets were used, containing n‐3HUFA concentrations of 1.6 (control), 4.8, 7.4, 13.9, 23.9, 29.2 and 34.4 g/kg, respectively. Two 8‐week feeding trials were conducted to determine the dietary n‐3HUFA requirements of L. vannamei with an initial body weight of 4.25 ± 0.00 g (subadults) and 8.50 ± 0.01 g (adults). The results showed that the dietary n‐3HUFA level significantly affected the weight gain rate (WGR), specific growth rate, the feed conversion ratio and the hepatosomatic index (HSI) (p < 0.05), but did not significantly affect the survival rate (p > 0.05). At appropriate level, dietary n‐3HUFA improved growth performance and HSI of both subadult and adult L. vannamei. Both subadults and adults showed significant differences in body composition (p < 0.05), except for moisture and crude ash (p > 0.05). Cholesterol and low‐density lipoprotein significantly decreased with increasing dietary n‐3HUFA both in subadults and adults (p < 0.05); however, triglyceride showed no significant change (p > 0.05). High‐density lipoprotein (HDL) in subadults was significantly affected by dietary n‐3HUFA (p < 0.05), but followed no apparent regularity; HDL significantly changed in adults and showed an upward trend followed by a downward trend (p < 0.05). There was no significant effect on aspartate transaminase (AST) activity in subadults, but AST in adults and alanine transaminase (ALT) in subadults and adults were significantly affected (p < 0.05). Dietary n‐3HUFA significantly affected serum polyphend oxidase, malic dehydrogenase, alkaline phosphatase, superoxide dismutase and sodium‐potassium adenosine triphosphatase enzyme activities in gills (p < 0.05). The fatty acid composition of the shrimp tissue was associated with the fatty acid composition of the diet. Dietary n‐3HUFA supplementation significantly improved the contents of tissue ∑HUFA and n‐3HUFA, increased the n‐3/n‐6 ratio in the tail muscle and decreased the contents of tissue polyunsaturated fatty acid and saturated fatty acid (p < 0.05). Based on the WGR, the broken‐line equations indicated that the optimum requirements of dietary n‐3HUFA were determined to be 9.0 and 5.1 g/kg for subadult and adult L. vannamei, respectively.  相似文献   

18.
An 8‐week feeding experiment was aimed to investigate the effect of dietary tea polyphenols (TP) on growth, immunity and lipid metabolism in juvenile black carp Mylopharyngodon piceus (initial weight 5.90 ± 0.03 g). Tea polyphenols were added at different levels (0, 25, 50, 100 and 500 mg/kg; TP0, TP25, TP50, TP100 and TP500). The results are as follows: the highest specific growth rate (SGR) and condition factor (CF) and activity of trypsin (TRS) of intestine in TP50, but SGR and activities of lipase (LPS)and TRS of intestine and content of whole body crude protein in TP500 were remarkably lower than TP0. Compared with TP0, content of serum superoxide dismutase (SOD) and glutamic oxalacetic transaminase (GOT) remarkably increased (p < .05), but contents of glutathione (GSH), glutathione peroxidase (GSH‐Pox), malondialdehyde (MDA), triglyceride (TG) and low‐density lipoprotein cholesterol (LDL‐C) were significantly decreased (p < .05), content of cortisol was remarkably lower in TP50 and TP100 (p < .05), expression of growth hormone (GH) and melanocortin 4 receptor (MC4R) in liver and GH in muscle were remarkably up‐regulated in TP50, but expression of apolipoprotein A‐1 (ApoA1), GH and MC4R of intestine, ApoA1 of liver and MC4R of muscle in TP500 were remarkably down‐regulated, contents of complement 3 (C3), complement 4 (C4), high‐density lipoprotein cholesterol (HDL‐C) and LDL‐C were significantly reduced in TP500 (p < .05). In conclusion, TP could improve growth performance and oxidative capacity on juvenile black carp, and its optimal dosage was 50 mg/kg.  相似文献   

19.
Growth parameters of whiteleg shrimp Litopenaeus vannamei and red seaweed Gracilaria corticata were measured using integrated culturing method under zero‐water exchange system in a 45‐day period. A 2 × 3 factorial design was used with two levels of shrimp stocking densities and three levels of seaweed weight densities. G. corticata was cultured on a net tied to a round polyethylene frame. Culture tanks were filled with 750‐L filtered seawater. A 40‐W compact fluorescent lamp was hung over each tank to provide adequate and sufficient light for seaweed growth. Growth parameters of shrimp and seaweed such as specific growth rate (SGR), weight gained (WG) and average daily growth (ADG) were computed based on the initial and final weight of shrimp and seaweed. The maximum and minimum SGR of L. vannamei (1.97 and 1.69%/day) were observed in treatment S1A3 (25 shrimp/m2 and 400 g seaweed/m2) and S2A1 (50 shrimp/m2 without seaweed) respectively. The best survival rate (94.67 ± 1.33%), WG (129.9 ± 2.9%) and feed conversion ratio (1.67 ± 0.04) were also observed in treatment S1A3. The SGR of G.corticata in the treatment S1A3 (1.97 ± 0.00%/day) was significantly higher, compared to others. Strong positive correlations were obtained between the density of G. corticata and the growth parameters of L. vannamei. The red seaweed G. corticata could boost the growth parameters, survival rate and total production of L. vannamei under zero‐water exchange system.  相似文献   

20.
Allometric growth and ontogeny were studied in thick‐lipped grey mullet Chelon labrosus reared in mesocosms from 1 to 71 day post hatching (dph). Multivariate allometric analysis of morphometric growth distinguished three distinct developmental stanzas separated by two morphometric metamorphosis lengths (Lm1 = 4.46 ± 0.06 mm; Lm2 = 28.56 ± 1.04 mm). Body mass growth also showed three distinct episodes separated by two inflections, correlated with morpho‐functional changes. First episode concerned pre‐flexion larvae and ended around 4.5 mm‐LT (14‐dph), coinciding with estimated Lm1. It was distinguished by reduced growth, but intense morphogenesis and differentiation processes. Organogenesis and allometric changes indicated that development priorities concerned feeding efficiency, by improving detection ability (sensory system development), ingestion capacity (head growth) and assimilation performance (digestive system differentiation), together with respiration efficiency (gill development). Second episode concerned post‐flexion larvae and, ended around 8.6 mm‐LT (25‐dph). It was distinguished by fast growth of trunk and tail, acquisition of adult axial muscle distribution and completion of gill filament development, improving locomotion and oxygenation performances. It corresponded to transition towards metamorphosing stage as indicated by later isometric growth, musculature maturation and acquisition of juvenile phenotype. Metamorphosis seemed to end at Lm2, suggesting to avoid zootechnic handling before this size.  相似文献   

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