Dietary protein level and natural food management in the culture of blue (Litopenaeus stylirostris) and white shrimp (Litopenaeus vannamei) in microcosms

The effect of dietary protein level and natural food management on the production parameters of blue and white shrimp, as well as on water quality, was evaluated in a microcosms system (plastic pools simulating aquaculture ponds). Two experimental trials were carried out in the facilities of DICTUS, University of Sonora, Northwest México. Treatment with low protein diet (LP) consisted of a low protein input (diet with 250 g kg^?1 crude protein) through the culture period; treatment with high protein diet (HP) consisted of a high protein input (diet with 400 g kg^?1 crude protein) through the trial, and finally treatment VP consisted of an adjustment of protein input (diets with 250, 350 or 400 g kg^?1 crude protein), depending on the abundance of biota (zooplankton and benthos) in the system. Each species responded differently to the treatments. For blue shrimp, low protein input resulted in the lowest final body weight (12.9 ± 0.6 g) and biomass (696.0 g pool^?1). Survival and feed conversion ratio were similar in the three treatments. For white shrimp, the best growth, biomass and food conversion ratio were obtained in the low protein input treatment. Water quality parameters such as nitrate, ammonia and organic matter during the two trials, were better for LP and VP treatments. White shrimp seems to have lower protein requirements than blue shrimp. For the blue shrimp culture, adjusting protein input according to natural food abundance (zooplankton and benthos) in the system, seems to be advantageous because of the possibility of getting a production similar to that obtained with a high protein input through the farming period, but at lower feed cost, and with a lower environmental impact. It is concluded that a high protein input through the whole farming period is not the best feeding strategy for any of the two species.     

利用低盐度养殖的凡纳滨对虾培育亲虾初探

以在盐度2~3条件下养殖至9月龄的凡纳滨对虾( Litopenaeus vannamei )成虾为材料, 研究低盐度养殖对虾在不同盐度驯养条件下的繁殖性能, 以期为利用低盐度养殖对虾培育亲虾提供科学依据。实验盐度梯度设置为1、8、15、23和30。雌虾经剪切单侧眼柄后进行促熟培育, 促熟期间的雄虾养殖水温控制在(27±0.5)℃, 雌虾水温控制在(28±0.5)℃。定期检查雌虾卵巢和雄虾精荚的发育情况, 采用精荚人工移植技术对不同盐度条件下培育的亲虾进行组合交配, 统计受精率和孵化率, 组织切片观察卵巢发育, 综合评价各实验组合的繁殖性能。结果表明, 在实验盐度梯度范围内, 雌虾卵巢都可发育成熟; 盐度1组雌虾成熟比例仅10%, 且全部死亡; 盐度8和15下发育成熟的雌虾达70%, 可正常产卵, 但产出的卵子受精率较低, 不能孵化出无节幼体; 盐度23和30下发育成熟的雌虾超过76%, 可正常产卵、孵化, 但孵化率较低。组织切片观察, 盐度8~30范围内各组雌虾卵巢发育无明显差异。在盐度8~30范围内, 凡纳滨对虾雄虾精巢都能够正常发育成熟, 但盐度30和23实验组的雄虾精巢发育速度明显快于盐度15和8组; 随着盐度的降低, 精荚发育成熟所需要的时间明显延长; 所有盐度实验组的精荚被移植后都可与卵子受精并孵化出无节幼体。

     

内陆地区南美白对虾苗种淡化试验

在内陆地区利用工厂化设施、臭氧水处理系统进行南美白对虾苗种淡化。淡化周期为12~15d,苗种成活率为65%~85%,单位水体出苗量5.0×104~7.0×104尾/m3。每个育苗季节可淡化虾苗4.0×107~5.0×107尾,卤水使用量仅为30 m3,并且无药物投放。     

Quantitative dietary threonine requirement of juvenile Pacific white shrimp, Litopenaeus vannamei (Boone) reared in low-salinity water

An 8-week feeding trial was conducted to determine the threonine requirement of juvenile Pacific white shrimp Litopenaeus vannamei (Boone) in low-salinity water (0.50–1.50 g L⁻¹). Diets 1–6 were formulated to contain 360 g kg⁻¹ crude protein with fish meal, wheat gluten and pre-coated crystalline amino acids with six graded levels of l -threonine (9.9–19.0 g kg⁻¹ dry diet). Diet 7, which was served as a reference, contained only intact proteins (fish meal and wheat gluten). Each diet was randomly assigned to triplicate groups of 30 shrimps (0.48±0.01 g), each four times daily. Shrimps fed the reference diet had similar growth performance and feed utilization efficiency compared with shrimps fed the diets containing 13.3 g kg⁻¹ or higher threonine. Maximum specific growth rate (SGR) and protein efficiency ratio were obtained at 14.6 g kg⁻¹ dietary threonine, and increasing threonine beyond this level did not result in a better performance. Body compositions, triacyglycerol and total protein concentrations in haemolymph were significantly affected by the threonine level; however, the threonine contents in muscle, aspartate aminotransferase and alanine aminotransferase activities in haemolymph were not influenced by the dietary threonine levels. Broken-line regression analysis on SGR indicated that optimal dietary threonine requirement for L. vannamei was 13.6 g kg⁻¹ dry diet (37.8 g kg⁻¹ dietary protein).     

Effects of bioflocs on dietary protein requirement in juvenile whiteleg Shrimp,Litopenaeus vannamei

A feeding trial was carried out to determine the effects of bioflocs on dietary protein requirement in juvenile whiteleg shrimp, Litopenaeus vannamei. Four bioflocs treatments (BFT) and one control group were managed: BFT fed diets 25% of crude protein (CP) (BFT‐25%), 30% CP (BFT‐30%), 35% CP (BFT‐35%) and 40% CP (BFT‐40%), and clear water control without bioflocs fed with 40% CP (CW‐40%). Triplicate groups of shrimp (initial body weight, 1.3 g) were fed one of the test diets at a ratio of 7% body weight daily for 8 weeks. At the end of the feeding trial, significantly (P < 0.05) higher weight gain and specific growth rate were obtained in shrimp fed BFT‐35% and BFT‐40% compared to BFT‐25% and BFT‐30%. Shrimp fed BFT‐35% exhibited the lowest feed conversion ratio. Significantly higher muscle nucleic acid indices were also recorded such as DNA content in BFT‐30%, RNA content in BFT‐35% and RNA/DNA ratio than that of shrimp fed control. Total protein level in the haemolymph of shrimp fed BFT‐40% was significantly higher than those of shrimp fed BFT‐25% and BFT‐30%. Therefore, the present results demonstrated that, when L. vannamei juveniles were reared in bioflocs‐based tanks, dietary protein level could be reduced from 40% to 35% without any adverse effect on shrimp growth performance, body composition and haemolymph characteristics. [Correction added on 20 May 2015, after first online publication: sentence modified to clarify the reduction in dietary protein level.].     

跑道式南美白对虾养殖池中弧菌的数量动态

采用TCBS平板计数法对南美白对虾跑道式养殖池和土塘养殖塘水样弧菌数量进行了一个养殖周期的连续监测。结果表明:跑道式养殖池水体中弧菌数在放苗后的前70 d均较低,随后迅速增加并维持在一个较高水平,变化幅度为15.0~1.42×104cfu/ml,平均3.96×103cfu/ml,平均数比土塘高2倍。跑道式养殖对虾始终未发病,跑道式养虾病害少,产量高。     

Influence of variation in water temperature on survival,growth and yield of Pacific white shrimp Litopenaeus vannamei in inland ponds for low‐salinity culture

There is considerable interest in the culture of whiteleg shrimp (Litopenaeus vannamei) in inland low‐salinity water in Alabama and other states in the Sunbelt region of the US. However, the growing season is truncated as compared with tropical or subtropical areas where this species is typically cultured, and temperature is thought to be a major factor influencing shrimp production in the US. This study, conducted at Greene Prairie Aquafarm located in west‐central Alabama, considered water temperature patterns on a shrimp farm in different ponds and different years; and sought possible effects of bottom water temperature in ponds on variation in shrimp survival, growth and production. Water temperature at 1.2 m depth in 22 ponds and air temperature were monitored at 1‐hr intervals during the 2012, 2013, 2014 and 2015 growing seasons. Records of stocking rates, survival rates and production were provided by the farm owner. Correlation analysis and linear mixed model analysis of variance were used. Results showed that hourly water temperatures differed among ponds. The range of water temperature in each pond explained 41% of the variance in average final weight of shrimp harvested from each pond. In conclusion, the results suggest that variation in water temperature patterns has considerable influence on shrimp growth and survival in ponds.     

Biotic communities and feeding habits of Litopenaeus vannamei (Boone 1931) and Litopenaeus stylirostris (Stimpson 1974) in monoculture and polyculture semi-intensive ponds

Zooplankton, macrozoobenthos and feeding habits of Litopenaeus stylirostris and L. vannamei in monoculture and polyculture semi‐intensive experimental ponds were evaluated. Zooplankton was more abundant in monoculture of L. stylirostris (1002±670 organisms (org.) L^?1) than in monoculture of L. vannamei (470±37 org. L^?1), and polyculture (321±188 org. L^?1). The main zooplanktonic groups were polychaeta larvae, nauplii, copepods and polychaeta. Macrozoobenthos was more abundant in polyculture (6898±11 137 org. m^?2) compared with monoculture of L. stylirostris (3201±350 org. m^?2) and L. vannamei (2384±3752 org. m^?2). The main benthic groups were copepods, polychaeta, ostracods, nematodes and insects. Differences in feeding habits were found between species and regimes. Litopenaeus vannamei showed to be a more voracious species and fed mostly on organic detritus and benthos in both culture regimes. Litopenaeus stylirostris had a more restricted sources of feed in the ponds. The major component in the stomach content of both species was detritus. Macroalgae, sand, exuvia, formulated feed, prey and microalgae were minor components for both species (<7%). Ingestion of formulated feed was <4% for L. stylirostris and was not detected for L. vannamei. The stomach repletion rates were larger for L. vannamei (55.6% and 48.8%) than for L. stylirostris (43.75% and 44.89%). Litopenaeus stylirostris grew better in polyculture (10.3±3.4 g) that in monoculture (9.0±3.8 g). Litopenaeus vannamei grew better in monoculture (16.1±4.8 g) than in polyculture (13.4±4.5 g). For both species, feed conversion ratio was lower in polyculture.     

中肋骨条藻对低盐水虾池养殖生态的影响

中肋骨条藻是海水富营养化的标志性微藻和常见赤潮生物之一。在陆源低盐水中养殖南美白对虾期间,池塘里出现了持续时间较长的优势种中肋骨条藻。其对池塘生态的影响,本文做了初步的描述。相应的低盐度盐水高密度养虾模式的生态也做了初浅的划分。     

Effect of salinity on natural community and production of Litopenaeus vannamei (Boone), within experimental zero-water exchange culture systems

Recent efforts have been made to culture marine shrimp in systems operating under low or zero‐water exchange and with decreased water salinity. The aim of this study was to investigate the impact of various salinity levels on qualitative and quantitative characteristics of the natural community and, more particularly, ciliated protozoa, and compare this information with shrimp growth and survival. Tanks with 9‰ salinity were characterized by a higher pH, but also by a significantly higher concentration of chlorophyll a (Chl a) per weight of suspended matter (1.93 ± 0.72 µg Chl a/mg TSS) than tanks with 18‰ (1.29 ± 0.68 µg Chl a/mg TSS) or 36‰ (1.37 ± 0.61 µg Chl a/mg TSS) salinity. Concentrations of ciliates (max 6000 cells mL^?1) showed considerable fluctuations over the sampling period, reflecting the impact of water salinity, dynamic interactions between ciliates and their diverse roles within the shrimp production system. There was no significant difference between survival rates of shrimp reared at 9‰, 18‰ or 36‰, but decreasing salinity from 36‰ to 9‰ led to a significant decrease in final shrimp body weight (from 13.40 ± 0.26 g to 10.23 ± 2.72 g). Future work should address the potential of ciliates as an indicator of aquaculture water quality, as is currently being done in the wastewater industry, and the contribution of ciliates as food sources.     

Morphometric relationships among spermatophore structures and their association with female fertility in the Pacific white shrimp Litopenaeus vannamei

ABSTRACT

Male reproductive performance affects production in shrimp hatcheries. To help better define the criteria required to choose male broodstock, our objective was to study associations among spermatophore morphometric traits and their relationship with fertility. The variables studied were male body weight (MBW), male body length (MBL), spermatophore weight (SW), sperm cell count (SCC), and percentage of live sperm cells (PLS). To evaluate fertility, female body weight (FBW) was considered, as well as the number of eggs in the spawn (NE), hatching percentage (HP), and the number of nauplii (NN). A random sample of 200 males and 200 females from the broodstock population were obtained. Correlations of SW with body MBW and MBL were estimated as 0.86 ± 0.02 and 0.63 ± 0.04 respectively. Correlations between the SCC with MBW and SW were estimated as 0.52 ± 0.05 and 0.61 ± 0.04 respectively. No linear associations were observed between MBW, SW, and SCC, with the NN (P > 0.05). Also, there was no linear relationship between FBW and NN (P > 0.05). On the other hand, FBW and NE were positively correlated (0.33 ± 0.07). HP showed a wide variation (2.6% to 98%) due to the multiple factors associated with artificial insemination.     

Pond-to-pond variability in post-larval shrimp, Litopenaeus vannamei, survival and growth in inland low-salinity waters of west Alabama

Despite the recent success of Alabama shrimp farmers in culturing the Pacific white shrimp, Litopenaeus vannamei , in inland low-salinity waters there is large variability in growth and survival among ponds. Farmers suspect that high mortality occurs during the first weeks of culture following stocking of postlarvae (PL). In order to determine the effect of pond ionic composition on PL growth and survival, three trials were carried out at a shrimp farm. Trials 1 and 2 evaluated PL growth and survival over 21- and 28-day periods, respectively, using static water from different production ponds. Trial 3 evaluated growth and survival over 7, 14, 21 and 28 days using water from one production pond. Results suggest that initial mortality (8–10%) is attributed to the acclimation process and occurs immediately following stocking. Pond-to-pond variations in ionic profiles could be a contributing factor but are not likely the major reason for variable 'survival'. Mortalities after stocking appear to occur quickly as there were no differences in survival from 7 to 28 days post stock. Variable survival is likely due to a combination of reasons including environmental factors, but is largely due to poor handling of PL and stocking errors that produce perceived reductions in survival.     

Dietary magnesium requirement and physiological responses of marine shrimp Litopenaeus vannamei reared in low salinity water

An 8‐week feeding experiment was conducted to determine the dietary magnesium (Mg) requirement and physiological responses of Litopenaeus vannamei in low salinity water of 2 g L^?1. Casein–gelatin‐based diets supplemented with seven levels of Mg (0, 0.4, 0.8, 1.6, 3.2, 6.4 and 8.0 g kg^?1) were fed to juvenile shrimp. Prior to the experiment, the postlarvae were gradually acclimated to the low salinity media and fed with a basal diet (0.5 g Mg kg^?1) for 2 weeks. After 8 weeks of feeding, survival ranged from 80.11% to 85.65% with no significant difference among the treatments. Hepatopancreas Mg²⁺‐ATPase and Na⁺/K⁺‐ATPase activities and muscle content of lipid and protein were not significantly affected by graded levels of Mg. The weight gain and mineral (calcium, potassium, sodium and total phosphorus) content of different tissues were significantly affected by dietary Mg levels, while there were no significant differences in ash and zinc content in tissues. The Mg content in tissues except hepatopancreas was maintained relatively constant regardless of dietary treatments. The dietary Mg requirement for optimal growth was 2.60–3.46 g Mg kg^?1 by using the polynomial regression analysis based on growth.     

养殖南美白对虾桃拉综合征病原的确认及其组织病理学观察

应用RT-PCR技术,对福建南部养殖南美白对虾(Litopenaeus vannamei)自然暴发的急性传染病病原进行了检测。结果检出桃拉综合征病毒。对231bp的扩增产物进行了测序,并与Genbank桃拉综合征病毒相应序列进行比较,其同源性超过97．O％。临床观察也表明,虾体表发红、有的虾体表散布有一些灰白色病灶,附肢及尾扇发红,还有一些病虾体表散布大量黑色不规则病灶,为桃拉综合征病毒感染引起的典型症状。组织病理学检查表明,病虾体表、附肢、鳃等组织的表皮上皮有许多坏死病灶,结缔组织细胞与相邻横纹肌纤维基底部也有病变。病变细胞嗜酸性颗粒增多,细胞核固缩或破裂。部分病虾肝胰腺出现脂肪化和空泡变性。     

凡纳滨对虾对东北碳酸盐类盐碱水的驯化适应

采用虾塘水添加天然盐碱水的方法,进行凡纳滨对虾(Litopenaeus vannam eiBoone)对东北地区碳酸盐类盐碱水环境的驯化适应试验。结果表明,驯化速度采用每隔12 h、24 h、48 h分别提高1次碱度1、2、4 mmol/L,经过14 d,从碱度为3.17 mmol/L的盐碱水环境,分别驯化至30.44、29.13及27.32 mmol/L的水环境,幼虾的存活率分别为41%、39%及34%。通过驯化适应,可提高幼虾对碳酸盐类盐碱水环境的适应能力及其存活率。     

Effects of dietary lipid sources on growth and fatty acid composition of juvenile shrimp, Litopenaeus vannamei

This experiment was conducted to evaluate the effects of dietary lipid sources on the growth performance and fatty acid (FA) composition of juvenile shrimp, Litopenaeus vannamei. Six isoenergetic and isonitrogenous semi‐purified diets containing casein, solvent‐extracted soybean meal and gelatin as protein sources, were supplemented with 60 g kg⁻¹ of lipid sources. The lipid sources included: pollack fish oil (PO), pork lard (PL), soy oil (SO), peanut oil (PN), rapeseed oil (RO) and a mixture of pollack fish oil and soy oil (POSO 1 : 1 w/w). Each diet was fed to juvenile shrimp (0.10 g average weight) four times daily in triplicate tanks to apparent satiation (feeding ratio was about 8%) for 8 weeks. At the end of the experiment, weight gain, specific growth rate and protein efficiency ratio were significantly higher for shrimp fed the diet containing PO and the POSO mixture oil than the other lipid sources. The nutritional values of SO, RO, PN and PL were similar. Shrimp fed on PO, mixture oil of POSO and SO had better survival rates than the other lipid sources, and shrimp fed the PL had the lowest survival rate. There were significant differences in lipid contents of whole body and hepatopancreas amongst the dietary treatments; however, lipid contents of tail muscle were not significantly affected by the dietary lipid sources. Shrimps fed POSO diet had higher protein content in whole body than those fed the other lipid sources, and shrimp fed PO diet had highest crude protein content of the tail muscle. A high correlation was found between dietary FA composition and FA composition of whole shrimp. FA composition of the whole body was generally affected by dietary lipid sources, especially dietary unsaturated FA.     

不同盐度下凡纳滨对虾扰动作用对沉积物-水界面营养盐通量的影响

采用室内培养方法,研究了三个盐度水平下(盐度分别为5‰,20‰,35‰)凡纳滨对虾的扰动作用对沉积物-水界面NH+4-N、NO-3-N、NO-2-N和SRP通量的影响。结果显示:凡纳滨对虾在三个盐度下都可以促进沉积物NH+4-N的释放,但是促进效果不相同,总体表现为盐度越高促进作用越明显;盐度为5‰时对虾对沉积物NO-3-N释放的促进作用最低,但对NO-2-N释放的促进作用最高;盐度为20‰时对虾对沉积物NO-3-N和NO-2-N释放的促进作用均较高,且对沉积物NO-3-N释放的促进作用是三个盐度水平下最高的。实验的前8d各盐度下对虾对SRP的促进效果没有显著差异,而实验持续到15d后高盐度组对虾的促进作用比低盐度组显著。     

Effects of dietary chitosan on growth,survival and stress tolerance of postlarval shrimp,Litopenaeus vannamei

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.