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1.
The gonadosomatic (GSI) and hepatosomatic (HSI) indexes are widely used for the evaluation of reproductive biology in crustaceans. However, the use of either wet or dry weight for estimating these indexes is not standardized in the literature. Here, we compare the GSI and HSI indexes based on wet and dry samples of females of Macrobrachium amazonicum from populations with different phenotypes (large and small‐size prawns) as a model. In our analysis, for GSI, the application of wet weight tended to overestimate the values recorded in the initial (I‐II) and intermediate (III) stages of ovarian development, and underestimate the results in the final (IV‐V) stages when compared to the use of dry weight. This could be attributed to the reduction in cytoplasmic organelles and water content of the cytosol due to the increase in yolk and lipids in the oocytes throughout ovarian development. For HSI, no significant differences were detected between wet and dry samples. However, the dry HSI computed at all stages of development was overestimated when compared to the use of wet samples, and only the hepatopancreas of females at the final stage (V) showed a significant decrease in water content. Thus, our results indicate that M. amazonicum females maintain constant hepatopancreatic reserves throughout ovarian development. In this way, the use of dry weight is more adequate to estimate GSI and HSI in this species.  相似文献   

2.
Cholesterol is a necessary element in the diet of prawns and it is involved in the metabolic processes of sexual maturation and synthesis of the molting hormone. Freshwater prawns are not able to synthesise cholesterol from specialised metabolic pathways. The aim of this study was to describe changes in structural and morphometric patterns of hepatopancreas associated with morphotypic differentiation of males Macrobrachium amazonicum when fed with different levels of cholesterol. Considering the four morphotypes of this species, Translucent Claw morphotype specimens were split into experimental units and divided into four groups, fed with different levels of cholesterol (0%, 0.5%, 1%, 2%) for 50 days. They were collected as they reached Green Claw (GC) morphotype, weighed to determine the hepatosomatic index, and the hepatopancreas was processed in histological routine for morphologic and morphometric analysis. In this study, it was possible to observe that the 2% cholesterol treatment exhibited more animals that reached the GC morphotype, and there was no significant weight gain in all treatments. Histologically, B‐cell abundance and hypervacuolized as well as F‐ and R‐cells shortages were observed as the percentage of cholesterol increased. This alteration in cellular profile correlates with the morphometric analyses that exhibited an increase in epithelial area and alterations in the lumen shape. This imbalance observed in the lumen‐epithelium relationship may be associated with a low digestive performance and possibly congested the functions of hepatopancreas. Thus, high doses of cholesterol promoted morphotypic differentiation without weight gain, due to alterations on hepatopancreas.  相似文献   

3.
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4.
The aim of this study was to evaluate the effects of hatchery‐tank colours (white, yellow, red, blue, green and black) on the performance of larval culture of Macrobrachium amazonicum. The larvae were fed daily with newly hatched Artemia nauplii. The hatchery‐tank colours affected the light level inside the tanks, the consumption of Artemia nauplii (AN), larval development, survival, mass gain and productivity of postlarvae (PL). The overall consumption of Artemia nauplii per larva during the larval cycle was 30% and 45% higher in the green and red tanks respectively. The significant variation of AN consumption among tank colours (P = 0.0006) indicates that M. amazonicum larvae are visual predators. Survival was higher in the black, blue and green tanks, reaching more than 75%. However, the highest productivity was obtained in the black tanks (80.1 PL L?1). Lighter coloured tanks and excess luminosity (more than 2 μmol s?1 m2 at tank bottom) appear to be important stress factors for larvae, contributing to reduce survival and productivity. The results indicate that rearing M. amazonicum in black tanks will improve larvae condition, ensure greater productivity of postlarvae and lower Artemia consumption, increasing technological and economic viability.  相似文献   

5.
The effects of intensification on growth, survival, productivity, population structure, and distribution of harvested biomass in individual size classes of Macrobrachium amazonicum in semi‐intensive culture were evaluated. Postlarvae (0.01 g) were stocked in 12 ponds at densities of 10, 20, 40, and 80/m2 (three replicates per treatment) and raised for 5.5 mo. Average individual weight significantly decreased and productivity significantly increased as stocking density increased (P < 0.001), while survival was not affected (P > 0.05). Prawn mean weight at harvest ranged from 3.6 (80/m2) to 7.0 g (10/m2). Average survival ranged from 65.5% (40/m2) to 72.8% (20/m2), while productivity ranged from 508 (10/m2) to 2051 kg/ha (80/m2). Harvested biomass showed a clear bimodal distribution in individual size classes indicating the occurrence of heterogeneous growth, which may affect management and market strategies. Harvested biomass of prawns weighing more than 7 g (the best market size) increases for stocking densities up to 40/m2 and stabilizes between 40 and 80/m2. Growth reduction was associated with a decreasing frequency and average weight of green claw 1 and green claw 2 male morphotypes and adult females as density increased. Thus, the distribution of male morphotypes and sexually mature females are affected by density‐dependent factors. Results suggest that prawn density plays an important role on M. amazonicum grow‐out phase, as has been demonstrated for other species of the genus Macrobrachium. M. amazonicum tolerates grow‐out intensification and may be raised in both semi‐intensive and intensive systems stocked at very high densities yielding high productivity.  相似文献   

6.
One of the bottlenecks in cultivating juvenile green abalone Haliotis fulgens is the lack of well‐adapted natural or formulated food for optimal growth. The goal of this study was to analyse the digestive gland structure of juvenile green abalone fed rehydrated natural feed, Ulva sp. (Chlorophyta), Eisenia arborea, Macrocystis pyrifera, Egregia menziesii (Phaeophyta) and Porphyra perforata (Rhodophyta), using histochemical techniques. Structure of the digestive gland was described, and proteoglycan granules were detected in the digestive cells. The abundance of granules was variable, depending on the feed provided to the abalone, and this was reflected in their growth. Granular content in digestive cells fed Ulva sp. was scarce, leading to low growth rate and high feed conversion ratio (FCR). Digestive cells of juveniles fed E. menziesii led to the best nutritional condition, including many proteoglycans cellular granules, best weight growth rate and a low FCR. Histochemical analysis of the digestive gland, differentiated by a modified Goldner trichrome method that included Alcian blue, was a useful tool for determining the nutritional status of farmed abalone, therefore recommended for assessing adjustments to the natural feed or formulation to meet the nutritional needs of abalone.  相似文献   

7.
Agave lechuguilla is a succulent plant species, mainly distributed in the northeast of Mexico and south of the United States of America. The main use for this plant is the fibre´s extraction (known as Tampico fibres), resulting in 15% of fibres and 85% of a by‐product waste named guishe. The lechuguilla collectors, normally incinerate the guishe, thus causing environmental contamination. Interestingly, recent studies showed that guishe contains molecules with nutritional properties, such as saponins, flavonoids and sugars. Therefore, in this work, we evaluated the effect of the crude extract of guishe as a feed additive in whiteleg shrimp diets. According to that, MS‐HPLC analysis of the extract showed the presence of saponins such as diosgenin, smilagenin, hecogenin, manogenin, tigogenin hexose, yucagenin, chlorogenin, diosgenin diglucoside and the flavonol, quercetin. After chemical analysis, the crude extract was included into an experimental diet in four levels; 0% (L0%), 0.1% (L0.1%), 0.3% (L0.3%) and 0.6% (L0.6%). Dietary incorporation of the extract was evaluated by zootechnical performance, haemolymph biochemistry, histomorphology and digestive enzyme activity of shrimps. After 5‐week feeding, the L0.3% diet showed significantly higher growth and better feed utilization among treatments. A significant increase in tubule epithelium height and tubule coverage area from hepatopancreas in shrimp under L0.3% diet compared with the control diet suggest an improvement of the health and nutritional status of the shrimp. Inclusion of L0.3% and L0.6% of the crude extract resulted in a reduction in amylase activity, without effect in glucose levels in the haemolymph. Thus, we suggest that lechuguilla guishe crude extract contains nutritional molecules that may be used as a feed additive to promote shrimp productivity.  相似文献   

8.
In aquaculture, exposure to stressful conditions and problems related to diseases often occur resulting in serious economic loss. The use of probiotics that control pathogens through different mechanisms, aiding digestion by exoenzyme supply and establishment of beneficial microflora in the digestive tract has got increased attention recently. Two different bacterial species Micrococcus MCCB 104 and Bacillus MCCB 101 were tested as probiotics for two cichlid species Etroplus suratensis and Oreochromis mossambicus. The strains were administered separately and together, at a rate of 103 CFU animal?1 day?1 for 28 days. The effects on digestive enzyme activity and growth were compared with those fed on control diet. FCR of E. suratensis was high in case of Bacillus alone as well as the mixed culture (Micrococcus and Bacillus together) than that of control. However, the SGR of E. suratensis was slightly lower than that of control during 14 days trial. SGR of both the treatments (Bacillus alone and mixed culture) was higher than that of the control on 28th day, and this might be due to the reason that specific duration is needed for the assimilation and conversion of nutrients into proteins. The intestinal digestive hydrolases of E. suratensis were profoundly enhanced mainly by Bacillus and mixed cultures. The hepatopancreatic versions of major digestive enzymes in E. suratensis were influenced variously by different probiotic treatments. The alpha‐amylase activity of hepatopancreas has been elevated significantly by mixed culture during 14 days experiments while on 28 days trials both Bacillus and mixed culture showed an enhancing effect. During 14 days feeding trials, the intestinal lipase activity has been prominently enhanced by all probiotic treatments. It is found that, in O. mossambicus, both 14 days and 28 days feeding experiments, the pepsin as well as intestinal digestive enzymes such as amylase, total alkaline protease, lipase and their hepatopancreatic counter parts showed a significant elevation in their specific activity. Intestinal alpha‐amylase and total alkaline proteases of O. mossambicus showed an increase in specific activities on both 14 days and 28 days feeding experiments with the Bacillus and Micrococcus combination. The hepatopancreatic enzymes were highly influenced by the Bacillus species in O. mossambicus. The results of this study suggest that live probiotic microorganisms such as Micrococcus MCCB 104 and Bacillus MCCB 101 may be incorporated while formulating the cost‐effective, nutritionally balanced diet of E. suratensis and O. mossambicus for better growth performance and nutrient utilization.  相似文献   

9.
This study has investigated the influence of unilateral eyestalk ablation on the survival, molting frequency, fecundity, reproductive output, and fertility of M. amazonicum females. We divided 96 females into with ablation and without ablation groups with six replicates. Water quality, growth, survival rate, intermolt period, molts number, and ovigerous females over a 90-day period were monitored. Unilateral eyestalk ablation reduced intermolt period by 30% and increased molts number, ovigerous females, and reproductive output. Our findings indicate that unilateral eyestalk ablation positively influences reproduction in M. amazonicum and is appropriate for females of this species having a body length of ≥ 70 mm.  相似文献   

10.
One of the bottlenecks for the queen conch, Strombus gigas, aquaculture is the lack of well‐adapted formulated food for optimal growth. The goals of this study were to analyse the digestive gland structure of conchs fed with different diets using histochemical techniques and to evaluate the growth and survival of S. gigas juveniles with nine formulated diets (protein from 190 to 380 g kg?1 and lipids from 26 to 82 g kg?1). Proteoglycan granules and acidophilic granules were detected in the digestive cells. The abundance of both granule types was variable, according to the nutritional state of the animals. The granular content of the digestive cells of conchs fed with artificial diets was scarce when compared with conchs fed on natural food. Of the nine formulated feeds, the diet with 365 and 45 g kg?1 of protein and lipids, respectively, gave the best growth in weight (0.20 g day?1) and was also associated with digestive cells in the best condition as determined histologically. Histochemical analysis of the digestive gland differentiated with Alcian blue staining determines the nutritional status much better than a simple growth index and is therefore more useful in assessing adjustments to the feed formulation to meet the real needs of conchs.  相似文献   

11.
Outbreaks of acute hepatopancreatic necrosis disease (AHPND) have caused great economic losses to many shrimp‐producing countries in Asia since its first appearance in 2009. The causative agent was reported in 2013 as specific isolates of Vibrio parahaemolyticus (VPAHPND) that were later found to harbor a plasmid (pVA) encoding the Pir‐like binary toxin genes Pir vpA and Pir vpB. VPAHPND isolates colonize the shrimp stomach and release the binary toxins that cause massive sloughing of tubule epithelial cells followed by shrimp mortality. More recent information indicates that pVA plasmid and variants occur in many V. parahaemolyticus serotypes and also in other Vibrio species such as Vibrio campbellii, Vibrio harveyi, and Vibrio owensii. Information on such genomic and proteomic studies of different VPAHPND isolates from different countries are reviewed. A cohort study carried out in Thailand in 2014 indicated that AHPND outbreaks account for only a portion of the disease outbreaks reported by shrimp farmers as outbreaks of early mortality syndrome (EMS). It is recommended that a regional research network and surveillance program for newly emerging or re‐emerging pathogens be established to speed up the process of diagnosis and the implementation of coordinated control measures and to avoid a repeat of the EMS/AHPND scenario.  相似文献   

12.
Feeding restriction is a strategy in shrimp farming management that may promote compensatory growth after feeding is re‐established. This study aims to evaluate the effects of two feeding restriction regimens on the compensatory growth and digestive enzymes activity of Litopenaeus vannamei reared in biofloc system. Juvenile shrimp (0.46 ± 0.18 g) were stocked (320 individuals/m3) in 310 L tanks. The experiment comprised two phases: (a) Feeding Restriction (30 days) when shrimp were submitted to three feeding regimes, Control (fed daily), R1F1 (repetitively fasted one day and fed one day) and R2F1 (repetitively fasted 2 days and fed 1 day); and (b) Refeeding (28 days) when shrimp were fed daily. In the restriction phase, shrimp growth and digestive enzyme activities were reduced in R2F1 and R1F1. However, during the refeeding phase, enzyme activities and feed conversion improve significantly in R2F1 and R1F1. Control group attained higher final weight, but its final biomass was similar to R1F1. Litopenaeus vannamei exhibited partial compensatory growth, probably due to improved feed conversion efficiency driven by increased enzyme activity. It is possible to reduce feeding by 50% (R1F1) in biofloc systems for 28 days, without compromising the biomass produced at the end of a 30‐day refeeding period.  相似文献   

13.
Adults from spider crab, Maja brachydactyla, Balss, 1922 were kept in captivity for up to 2 years. Haemolymph of ten females was extracted monthly for monitoring several metabolites and the presence of Vibrionacea bacteria. A neurotoxic marker and hepatic metabolic and digestive enzyme capacities were contrasted between wild specimens and those reared in captivity. As a result, no differences were observed in hepatosomatic index (HSI) between males and females, but captive animals presented lower HSI than the wild ones. After 2 years of confinement, no changes in quantities of haemolymph microflora and metabolites were observed and this was considered indicative of adaptation of the broodstock to confinement. Spider crab also showed a large plasticity in their hepatopancreatic digestive capabilities suggested by the adaptation to the food supplied in captivity. Moreover, captivity conditions did not seem to negatively alter their antioxidant defences, xenobiotic capacity or neuromuscular activity, as no enhanced oxidative stress damage was shown in either males or females. These results indicate that although the confinement conditions used in this study do not mimic those from the wild, they could be considered as adequate for rearing M. brachydactyla in captivity, at least with regard to the set of parameters assessed.  相似文献   

14.
杨代勤 《水产学报》2006,30(5):676-682
研究了饲料中添用不同含量胆碱对黄鳝生长、饲料利用效率、肌肉和肝脏脂肪含量、肝体指数及消化器官4种消化酶活性的影响。结果表明，饲料中添加的胆碱含量不同，对黄鳝的影响不同，饲料中胆碱添加量在0～2.0％内，随着胆碱添加量的提高，黄鳝的生长速度会加快，饲料系数会逐步降低，肌肉、肝脏的脂肪含量及肝体指数降低，前肠、后肠和肝脏的蛋白酶、胰蛋白酶、淀粉酶和脂肪酶的活性均会相应的提高，而且饲料中的添加量达0.8%～1.0％时，这些变化显著，表明胆碱对黄鳝是不可缺少的，黄鳝饲料中胆碱的适宜添加量为0.8%～1.0％。  相似文献   

15.
The effects of artificial substrate and night‐time aeration on the culture of Macrobrachium amazonicum were evaluated in 12 ponds stocked with 45 prawns m?2. A completely randomized design in 2 × 2 factorial scheme with three replicates was used. The combination of factors resulted in four treatments: with substrate and aeration (SA), with substrate and without aeration (SWA), without substrate and with aeration (WSA) and without substrate and aeration (WSWA). The presence of substrate in SA and SWA treatments reduced suspended particles (seston) by ~17.3% and P‐orthophosphate by ~50%. The use of aerator (WSA and SA treatments) significantly (P < 0.05) increased the concentration of dissolved oxygen, suspended particles and nutrients in the pond water. These results indicate that the effect of substrate on turbidity and total suspended solids (TSS) values is opposite to the effect of the aerator. The aerators in semi‐intensive grow‐out M. amazonicum farming lower water quality because they increased the amount of detritus and nutrients in the pond water. On the other hand, the use of artificial substrate reduces turbidity values, chlorophyll a, TSS and P‐orthophosphate concentrations. Therefore, the combination of substrate addition and night‐time aeration is not interesting because they have opposite effects.  相似文献   

16.
The activity and capacity (activity × tissue weight) of digestive carbohydrases (total carbohydrase, α‐glucosidase, α‐amylase) was examined in vitro under a range of (more realistic) incubation temperatures (5, 18 and 25°C) and pH (7.6) more likely to be encountered during rearing, along the digestive tract of important teleost species for aquaculture (Dicentrarchus labrax, Sparus aurata, Oreochromis aureus, Oncorhynchus mykiss and Salmo salar). Results indicate, among other things, an overestimation of digestive carbohydrase levels when performing assays at 37°C, a different effect of temperature on digestive enzyme performance along the digestive tract of examined species, and the increased importance of α‐glucosidase towards carbohydrate digestion. Implications regarding the capacity of each species for carbohydrate digestion in nature, as well as feed manufacturing, are discussed.  相似文献   

17.
Information on the bacterial community associated with octopus is very scarce, unlike fish and other molluscs. This study revealed the bacterial community associated with digestive tract of wild Chilean octopus Octopus mimus using a culture‐dependent method and 16S rDNA clone library. Moreover, we analysed the bacterial nutritional enzyme activity of culturable bacteria. A culture‐dependent method showed that the composition of the culturable bacterial community was substantially different between female and male octopus. The predominant species in female octopus were Vibrionaceae and Streptococcaceae, whereas only Vibrionaceae was dominated in male octopus. Bacterial nutritional enzyme activities of culturable bacteria from male octopus were much higher than female octopus. The 16S rDNA clone library analysis showed that the bacterial community of male octopus exhibited a higher diversity than that of female octopus. The genus Mycoplasma was the predominant bacteria in the digestive tract of all octopus samples. The results obtained in this study raise the possibility that each octopus has different food consumption due to different bacterial community and nutritional enzyme activity, although Mycoplasma sp. is one of the predominant bacteria in the digestive tract. Moreover, our results are useful for the future of microbiological investigation associated with the octopus and for probiotics in the octopus aquaculture.  相似文献   

18.
As an ecologically sustainable aquaculture mode, the rice‐fish approach has been paid more attention in recent years. In rice paddies, there are plant and animal diet items available to fish, but it is not clear how common carp adapt to different diets. In view of this, common carp (initial weight 492.6 ± 30 g, n = 270) were randomly divided into three groups and fed with earthworms (group A), earthworms + duckweed (group M) and duckweed (group P) respectively. After 8 weeks under these feeding regimes, the intestinal digestive enzymes activities were assayed, and intestinal tissue sections stained with HE and AB‐PAS were used to observe the morphology. The results showed that the activities of trypsin and lipase were highest in group A, followed by group M and group P. Group A had greater intestinal fold height, fold width and fold absorption area than the other groups (p < .05), especially in the foregut. Meanwhile, the total number of mucous cells was largest in group P, followed by the groups M and A. Totally, activities and distributions of digestive enzymes, fold height, fold width, fold absorption area and number and distribution of mucous cells of common carp were affected by the type of diet. Based on these results, it was found that common carp has strong adaptability to diets, and it was speculated that the majority of digestion and absorption of protein was concentrated in the foregut, while for starch and cellulose, it was spread out along the whole intestine.  相似文献   

19.
The veined rapa whelk, Rapana venosa (Valenciennes, 1846), is an important and valuable fishery species; however, it has not been routinely artificially cultured on a large scale. Here, we studied the effect of temperature (6, 16, 22 and 28°C) on the digestive enzymes in R. venosa of different sizes (Juvenile (small, S: 1.2–1.8 cm) and adult (medium, M: 4.1–5.2 cm; large, L: 7.6–8.9 cm)) by detected the enzyme activity in different digestive glands (the salivary gland, Leiblein's gland (oesophageal gland) and liver) using spectrophotometric method, to determine the optimal temperature for artificial cultivation and to explore the feeding habits of this whelk. The optimal temperature was determined to be approximately 22°C. The food intake was significantly higher at 22°C than at other temperatures, and the activity of the digestive enzyme, trypsin, was at the highest in the main digestive gland of R. venosa, the liver, at 22°C. In addition, the observed presence of cellulase and α‐amylase may suggest that carbohydrates are necessary during R. venosa development. The results of this study will help in the formulation of technical procedures for R. venosa aquaculture and in preventing its overexploitation, and explained its invasion mechanism to some extent.  相似文献   

20.
Various research projects in Europe and North Africa have recently intended to breed temperate holothurians to alleviate fishing pressure on natural populations. However, to date little is known about the nutritional requirements of East Atlantic and Mediterranean species. In this study, we propose a “natural population”‐oriented approach to characterize food sources, digestive efficiency and resources allocation based on the composition of pigments and fatty acids (FA) in gut contents and tissues (muscles, gonads and digestive tract walls) of wild individuals of the species Holothuria (Panningothuria) forskali (Delle Chiaje, 1823) sampled in Brittany (France). Our study reveals that neither green nor red algae enter the diet of H. forskali in spring and that the only fresh vegetal material found in gut contents is brown algae (very likely diatoms). The high nutritional quality of gut contents however contrasts with the detrital nature of the ingested food sources, suggesting that a trophic upgrading of organic matter occurs before digestion. In addition, unusual FA (i.e. only present in a few groups of living species) such as long‐chain monounsaturated FA (especially the FA 23:1ω9) were found in large proportions in muscles and gonad and their effect on sea cucumber fitness needs further investigation.  相似文献   

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