氨氮促使携带白斑综合症病毒凡纳滨对虾发病及其血细胞、酚氧化酶和过氧化氢酶变化

通过白斑综合症病毒(WSSV)感染得到携带WSSV病毒的凡纳滨对虾,它们由0.05 mg/L氨氮水体进入不同氨氮浓度水体,在7 d内,1.75 mg/L,2.25 mg/L,3.00 mg/L氨氮水体内个体发生病毒病,并产生死亡。在14 d内,0.75 mg/L氨氮以及大于这一浓度水体内个体发生病毒病,并产生死亡,其中3.00 mg/L氨氮水体内死亡100%,2.25 mg/L氨氮水体内死亡80%,1.75 mg/L水体内死亡60%。在0.35 mg/L氨氮水体,7-14 d内对虾开始发病,没产生死亡。发病个体血细胞数量下降迅速,血清酚氧化酶先增高再迅速下降,其中3 mg/L氨氮水体中的携带病毒对虾只有下降。同时氨氮浓度越大,携带病毒凡纳滨对虾血清过氧化氢酶活力下降越快,越多。     

Influence of stocking density on the behaviour of juvenile Litopenaeus vannamei (Boone, 1931)

Applied ethology can help to improve Litopenaeus vannamei aquaculture. Our purpose was to demonstrate an influence of stocking density on behaviour. The shrimp were first distributed in aquaria and observed via an ad libitum observational method to construct an ethogram of social and feeding behavioural categories. The resulting ethogram consisted of retreat, cannibalism, getting to the feeding tray, occupying the feeding tray and getting feed. We then kept shrimp in aquaria at densities of 50, 75 and 100 animals m^?2 and observed them via a behavioural sampling method using our ethogram as well as focal animal sampling of behaviours derived from the literature. These literature‐derived behaviours consisted of inactivity, feeding, crawling, exploration, burying, swimming and cleaning. We found that stocking density affects the behaviour of the shrimp. Optimal searching and feeding and a low frequency of crawling and swimming occurred at a density of 50 animals m^?2, indicating a higher potential for growth and welfare at this density.     

Effects of replacing fish oil with stearine as main lipid source in diet on growth and survival of Pacific White Shrimp,Litopenaeus vannamei (Boone, 1931)

The stearine fraction from raw fish oil refinement has been treated as a waste material. This study was conducted to evaluate effects of replacing prime refined fish oil with stearine as the main lipid source to a control diet on shrimp growth and survival as well as on pellet water stability of diets. Test diets were processed containing three levels (0.7%, 1.3% and 2.7%) of either stearine or refined fish oil in a semi‐purified control diet. These diets were each assigned to five or six replicated tanks and each tank was stocked with seventeen juvenile shrimp (ca. 0.50 g) in an indoor seawater recirculating system. At the end of 6 weeks, the survival of shrimp was 89.4–95.3% with no significant difference (P > 0.05) among dietary treatments. The six test diets obtained significantly higher (P < 0.05) shrimp growth rates (1.46–1.83 g week^?1) than the control diet (1.38 g week^?1). The shrimp that were fed the three stearine‐added diets exhibited high growth rates (1.75–1.83 g week^?1). Increasing the inclusion level of the stearine improved pellet water stability (91.7–93.9%; P < 0.05). These results suggest that stearine can replace fish oil in shrimp feed based on the growth performance.     

Selectivity of particle size by the shrimp Litopenaeus vannamei (Boone, 1931) larvae

Because of the filter‐feeding behavior of shrimp larvae, it is important to define precisely the size of the particle ingested in the different stages until postlarval stage where raptorial habits are more evident than the filter‐feeding lifestyle. Selectivity assays were conducted by using Polystyrene DVB particles with diameter between 1 and 50 μm as food. A group of organisms from each stage were put into the particle suspension for 15 min to let the polystyrene particles be ingested. The particle distribution in the media and the content of the gut of the larvae were characterized with digital image processing analysis. The results were compared using Ivlev selectivity formula, which compares the frequency distribution of each size of the particle in the media and in the gut of larvae. The results of selectivity were adjusted with a third‐order polynomial regression to determine the optimum and preferred size of the food particles for each larval stage between Zoea I and Postlarva I. It is concluded that the different larval stages of Litopenaeus vannamei may be considered as a single group of larvae who ingest foods with size between 5.71 and 20.33 μm. The optimal size of the food ingested was 14.42 μm wide.     

凡纳滨对虾饲料添加剂的研究进展

凡纳滨对虾(Litopenaeus vannamei)俗称南美白对虾,是目前世界养殖产量最高的三大虾种之一,具有对水环境抗逆能力强、营养要求低、生长速度快,虾体含肉量大、肉质鲜美、营养丰富等诸多优点,自1998年来,在广东、广西、海南等省(区)广为     

The Effect of Low Salinity Water with Different Ionic Composition on the Growth and Survival of Litopenaeus vannamei (Boone, 1931) in Intensive Culture

The effects of four different ionic composition low salinity water (T₁, T₂, T₃, and T₄), on growth and survival of Litopenaeus vannamei marine shrimp juveniles were investigated. Shrimp culture in seawater (T_m) was used as control treatment. The results indicated that there were no significant difference (P < 0.05) in growth, survival, production, and feed conversion ratio (FCR) of L. vannamei juveniles reared in the different treatments, but significant differences (P < 0.05) were observed between each of them when compared with seawater (T_m). After 84 days, culture shrimp grew from 0.02 to 7.58 g in T₁. The lowest growth rate was attained in T₃ (0.57 g/week), in which potassium and calcium ions concentrations were the lowest (0.58 and 28.00 mg/L, respectively). The recorded survival rate (76.35% to 79.55%) is considered well for the 84 days growout period, although it was 7.6% lower than that recorded in the control treatment. Although there were no significant differences (P < 0.05) in growth with respect to the ionic composition of the four treatments, there was a trend of increasing growth in relation with the ionic ratio found in the seawater (T_m). This aspect should be evaluated more closely in future research.     

Performance of Larval and Postlarval Pacific White Shrimp,Litopenaeus vannamei (Boone), Fed Two Commercial Liquid Diet Supplements

Abstract

Two commercial liquid diet supplements were evaluated as a partial replacement for live foods fed to larval and postlarval Pacific white shrimp, Litopenaeus vannamei. Larvae were stocked in 20-L buckets at a density of 113 shrimp/L and fed one of four diets (5 replicate buckets per diet): (1) a control diet consisting of the diatom, Chaetoceros neogracile, and live Artemia; (2) the control diet plus Treflan (a fungicide); (3) LiquaLife liquid larval diet supplements with reduced concentrations of C. neogracile and Artemia; and (4) Epifeed liquid larval diet supplements with reduced concentrations of Artemia. Diets were evaluated by comparing shrimp rostro-caudal length and survival to PL-8, survival to osmotic and pH stress, as well as shrimp gut fullness, gut lipid content, and fouling. Rostro-caudal length and survival to PL-8 were not significantly different among the four treatments. However, mean survival to PL-8 was 12-34% greater in the Epifeed treatment than in the other three treatments. Shrimp fed Epifeed exhibited greater survival (P < 0.05) when exposed to 7 ppt water for two hours than shrimp in the control treatments. In contrast, there was no significant difference in survival (P > 0.05) among the four treatments when shrimp were exposed to apH of 3.35 for two hours. Although shrimp fed liquid diet supplements had more fouling (P < 0.05) than shrimp in either of the control treatments, commercial liquid diet supplements can be used in penaeid shrimp hatcheries to partially replace Artemia without compromising shrimp growth or survival.     

Effect of Diet Size on Feeding Behavior and Growth of Pacific White Shrimp,Litopenaeus vannamei

Abstract

Six diet sizes, manufactured from crumbling large pellets, were investigated for their effect on the feeding behavior and growth of Pacific white shrimp, Litopenaeus vannamei. These diets containing 44.7% protein and 8.2% lipid were fed to 0.9 g shrimp for a period of eight weeks under indoor controlled laboratory conditions. Shrimp were stocked at a density of 12 animals per 52 L aquarium (50/m²) and were evaluated for feeding behavior, final weight, growth rate, feed conversion ratio (FCR), and survival. Feeding behavior was observed weekly starting at the beginning of the 4th week until the end of the trial. Results indicated that the variation in diet sizes did not produce significant differences in shrimp growth, FCR or survival. However, shrimp feeding behavior (in terms of total attacking incidents during feeding) was significantly different among diet sizes. This shrimp behavior was observed more frequently in aquaria fed larger diet size (3.0 mm pellet) as compared with those fed smaller diet sizes (0.7 mm and 1.2 mm crumbles). When shrimp were fed larger pellets, some of the individuals obstruct other individuals and monopolize the diet. Such “selfish” behavior of shrimp could result in considerable size variation and severe mortality of smaller individuals, which could be the case when shrimp are reared to market size. The effect of diet size on shrimp feeding behavior deserves further investigation and the use of a continuous monitoring device such as a video camera is strongly recommended. Future study should also consider various shrimp and pellet sizes more meaningful to aquaculture producers.     

Effect of different diets on growth and digestive enzyme activity in Litopenaeus vannamei (Boone, 1931) early post-larvae

Growth rate, soluble-protein content and digestive-enzyme activities were studied in Litopenaeus vannamei (Boone, 1931) early post-larvae under six feeding regimens, which included combinations of freshly hatched Artemia nauplii, an artificial diet and algae. Growth (0.11 mg DW day⁻¹) and soluble-protein content (61.8 μg protein larvae⁻¹ at PL₁₀) of post-larvae fed mixed diets were significantly higher (P < 0.05). An artificial diet used alone or co-fed with algae caused the lowest growth (0.03–0.05 mg DW day⁻¹) and soluble-protein content (13.7–15.5 μg protein larvae⁻¹ at PL₁₀). Trypsin-like activity was higher (up to 10 times) in post-larvae fed Artemia nauplii and an artificial diet alone or plus algae. The artificial diet stimulated chymotrypsin activity, apparently in response to squid meal present in this diet. Amylase activity increased when post-larvae were fed the artificial diet. This was apparently related more to the origin of the starch than to the total carbohydrate level of the diet. No obvious relationship was found between enzyme activity and growth in any feed combination. Based on growth and soluble-protein content, we determined that partial substitution (50%) of Artemia nauplii by artificial diet and the use of algae co-fed beyond the first post-larval stage benefits growth and the nutritional state of L. vannamei post-larvae.     

凡纳滨对虾在不同冷藏条件下的品质变化研究

通过感官评估、生化分析及蛋白质指纹图谱比较研究了4 ℃和0 ℃冷藏条件下凡纳滨对虾的品质变化,并对评价指标的有效性进行了分析.试验结果表明,0 ℃冷藏能延缓虾的腐败,比4 ℃更有利于凡纳滨对虾的保藏.虾肌肉的挥发性盐基氮(TVB-N)含量随贮藏时间的延长而增加,但在0 ℃条件下无法准确反映虾的品质变化.K值也随贮藏时间的延长而增加,且与感官评价之间存在良好的相关性,能反映凡纳滨对虾在冷藏初期的品质变化.而肌浆蛋白和肌纤蛋白的指纹图谱则能标记冷藏后期凡纳滨对虾肌肉蛋白发生的降解.     

Effect of Dietary Astaxanthin on Growth,Survival, and Stress Tolerance of Postlarval Shrimp,Litopenaeus vannamei

The effect of dietary astaxanthin on growth, survival, and stress tolerance was determined in postlarval Litopenaeus vannamei. An experiment was performed with postlarval shrimp (mean initial wet weight 1.2 mg) fed four isoenergic and isonitrogenous diets containing four supplemented levels of astaxanthin (0, 100, 200, and 400 mg/kg diet, respectively). Shrimp fed diets containing 100, 200, and 400 mg astaxanthin/kg diet for 30 d showed higher weight gain (WG, %) and survival compared to the control (without supplementation of astaxanthin). Specific growth rate (SGR, %/day) and final body wet weight (FBW, mg) showed the same pattern as WG. There were no significant differences in growth performance (FBW, WG, and SGR) among the groups fed the diets with astaxanthin supplementation at the termination of feeding trial. Survival of shrimp in the control and 100 mg/kg diet treatments was significantly lower than that of shrimp in the treatments with 200 and 400 mg/kg diet. After 9 d of a stress tolerance test, survival of shrimp in the 200 and 400 mg astaxanthin/kg treatments was significantly higher than that of shrimp in the 0 and 100 mg astaxanthin/kg treatments (P < 0.05). We concluded from this experiment that astaxanthin was a necessary ingredient for the development of larval L. vannamei. Considering the effect of astaxanthin on both, growth performance and survival of postlarval L. vannamei, the level of astaxanthin supplemented in the diet should be between 100 mg and 200 mg/kg of diet.     

Investigation of the Effects of Salinity and Dietary Protein Level on Growth and Survival of Pacific White Shrimp, Litopenaeus vannamei

It is presumed that in hypo‐ and hypersaline environments, shrimp’s requirements for some specific nutrients, such as protein, may differ from those known in the marine habitat; however, few investigations have been conducted in this area of study. In the present investigation, the effects of salinity and dietary protein level on the biological performance, tissue protein, and water content of Pacific white shrimp, Litopenaeus vannamei, were evaluated. In a 3 × 4 factorial experiment, juvenile shrimp with an average initial weight of 0.36 ± 0.02 g were exposed for 32 d to salinities of 2, 35, and 50 ppt and fed experimental diets with crude protein contents of 25, 30, 35, and 40%. A significant effect of salinity on growth of shrimp was detected, with the growth responses (final weight, weight gain) ranked in the order 2 ppt (3.87, 3.50 g) > 35 ppt (3.40, 3.04 g) > 50 ppt (2.84, 2.47 g). No effects of dietary protein level or an interaction between salinity and protein on growth of shrimp were observed under the experimental conditions of this study. Percent survival of shrimp fed the highest protein content (40%, survival of 74%) was, however, significantly lower than those of shrimp fed the other feeds (25, 30 and 35% protein, survival of 99, 91, and 94%, respectively), a result likely associated with the concentration of total ammonia nitrogen, which increased significantly at increasing protein levels. Final water content of whole shrimp was significantly lower in animals exposed to 50 ppt (70.8%) than in shrimp held at 2 (73.7%) and 35 ppt (72.3%). No effect of salinity, protein, or their interaction was observed on the protein content of whole shrimp. The results of the present study are in agreement with reports of superior and inferior growth of L. vannamei reared in hypo‐ and hypersaline environments, respectively, as compared to what is generally observed in seawater.     

Effects of Dietary Short-chain Fructooligosaccharides on Intestinal Microflora, Survival, and Growth Performance of Juvenile White Shrimp, Litopenaeus vannamei

Abstract.— Five groups of juvenile white shrimp, Litopenaeus vannamei , in triplicate were separately fed a compound diet with additional short-chain fructooligosaccharides (ScFOS, Profeed^® 95%) 0, 0.4, 0.8, 1.2, or 1.6 g/kg dried diet for 8 wk to investigate the effects of ScFOS on the intestinal microflora, survival, and growth performance of the shrimp. The juvenile shrimp with around 0.17 g of initial body weight were divided into 30 per tank and reared in a standard water recirculation system at 28 C. The shrimp were fed five times a day. At the end of experiment, the shrimp were weighed and their intestinal samples were analyzed for the amounts of Vibrio parahaemolyticus, Aeromonas hydrophila, Lactobacillus sp. , and Streptococcus faecalis using selective agar. The results showed that the shrimps' weight gain and specific growth rate increased with the increment of dietary ScFOS, while their feed conversion ratio decreased. The result was the best when an additional ScFOS 0.4 g/kg dried diet was used.     

不同盐度对生物絮团、对虾生长以及酶活性的影响

在不同盐度条件下进行凡纳滨对虾的生物絮团养殖试验,研究盐度对生物絮团养殖水质和对虾生长及其酶活性的影响。试验设5个盐度梯度(10、15、20、25、30),生物絮团初始量为20 mL/L,对虾密度为500尾/m^3,试验周期30 d。试验结果显示,15盐度组与20盐度组的对虾体质量增长率最大,达70.73%,10盐度组的体质量增长率最小,达50.24%。盐度越高生物絮团生长越快,30盐度组17 d生物絮团沉降量达200 mL/L,之后逐渐降至43 mL/L,其他组呈相同变化趋势。试验过程中水体总碱度与pH持续降低,但不同组间差异不显著(P>0.05)。盐度越高氨氮累积越快,30盐度组在第6 d达到最大质量浓度8.62 mg/L,之后降至0 mg/L,其他组呈相同趋势变化。盐度越低亚硝态氮累积越快,10盐度组在第6 d达到最大质量浓度9.18 mg/L,之后降至0 mg/L,其他组呈相同趋势变化。硝态氮在不同盐度中呈前期上升的趋势,第16 d之后开始缓慢下降。15盐度组的淀粉酶活性显著高于其他组(P<0.05),其他各组之间无显著差异(P>0.05)。脂肪酶在25盐度组活性最高,盐度升高或者降低酶活性均降低。在10、15、20盐度组中,超氧化物歧化酶、碱性磷酸酶、酸性磷酸酶活性均维持在较高水平,在相同盐度下,肌肉酶活性低于肝胰脏。     

Changes in Biochemical Compositions and Quality of White Shrimp (Litopenaeus vannamei) During Storage

ABSTRACT

To understand biochemical characteristics, storage stability, and freshness indicators of white shrimp (Litopenaeus vannamei), changes in extractable nitrogenous compounds, microbial count, and sensory rating of white shrimp during storage at 25 and 4°C were investigated. Free amino acids showed a slow increase during storage at 25°C, but no obvious change was found at 4°C. Adenosine triphosphate (ATP) and adenosine diphosphate (ADP) were found at initial stage and decreased rapidly after storage. Both inosine 5′-monophosphate (IMP) and adenosine monophosphate (AMP) increased and then decreased during storage. Inosine, hypoxanthine, and the K-value gradually increased with time. The levels of total volatile basic nitrogen (TVB-N), NH₃, and trimethylamine (TMA) of white shrimp increased with storage time at 25 and 4°C. The TVB-N, NH₃, TMA, inosine, hypoxanthine, and K-value could be considered as freshness indicators of white shrimp during storage. However, the total plate count did not corroborate the acceptability recommended limits for white shrimp during storage. The sensory evaluation, associated with TVB-N, TMA, and K-value, showed the quality was unacceptable after 6 h storage at 25°C and 7 days at 4°C.     

Effect of different biofloc system on water quality,biofloc composition and growth performance in Litopenaeus vannamei (Boone, 1931)

The experiment was conducted with three biofloc treatments and one control in triplicate in 500 L capacity indoor tanks. Biofloc tanks, filled with 350 L of water, were fed with sugarcane molasses (BFT_S), tapioca flour (BFT_T), wheat flour (BFT_W) and clean water as control without biofloc and allowed to stand for 30 days. The postlarvae of Litopenaeus vannamei (Boone, 1931) with an Average body weight of 0.15 ± 0.02 g were stocked at the rate of 130 PL m^?2 and cultured for a period of 60 days fed with pelleted feed at the rate of 1.5% of biomass. The total suspended solids (TSS) level was maintained at around 500 mg L^?1 in BFT tanks. The addition of carbohydrate significantly reduced the total ammonia‐N (TAN), nitrite‐N and nitrate‐N in water and it significantly increased the total heterotrophic bacteria (THB) population in the biofloc treatments. There was a significant difference in the final average body weight (8.49 ± 0.09 g) in the wheat flour treatment (BFT_W) than those treatment and control group of the shrimp. Survival of the shrimps was not affected by the treatments and ranged between 82.02% and 90.3%. The proximate and chemical composition of biofloc and proximate composition of the shrimp was significantly different between the biofloc treatments and control. Tintinids, ciliates, copepods, cyanobacteria and nematodes were identified in all the biofloc treatments, nematodes being the most dominant group of organisms in the biofloc. It could be concluded that the use of wheat flour (BFT_W) effectively enhanced the biofloc production and contributed towards better water quality which resulted in higher production of shrimp.     

不同抑制剂对凡纳滨对虾多酚氧化酶活性的影响

分析了凡纳滨对虾不同部位多酚氧化酶(PPO)活力的差异,并研究了抗坏血酸、曲酸、4-己基间苯二酚、葡萄糖酸-δ-内酯、植酸等抑制剂对对虾多酚氧化酶活力的抑制作用。试验结果表明,对虾头胸部的PPO活力最高。其中,0.12 g/L曲酸、2 g/L 4-己基间苯二酚5、g/L植酸对对虾PPO活力均有较好的抑制作用,对对虾处理30 min,抑制率分别为38%、36%、51%。