Use of Porcine Meal in Plant‐based Practical Diets for Pacific White Shrimp,Litopenaeus vannamei

Two growth trials were conducted to evaluate and confirm the efficacy of a porcine meal (PM) with high protein content (>90%) as an alternative feed ingredient in commercial‐type feed formulation for Pacific white shrimp, Litopenaeus vannamei. Six experimental diets were formulated for the two growth trials. The first five diets contained increasing levels (0, 1, 2, 4, and 6%) of PM as a replacement for soybean meal in a plant‐based diet with low inclusion level (6%) of fish meal (FM). The last experimental diet was produced utilizing 4.2% PM to completely replace FM. In Trial 1, shrimp (1.5 g initial mean weight, 20 shrimp/tank, n = 4) were offered test diets for 6 wk in a semirecirculation system. At the end of Trial 1, shrimp fed with the diet containing 6% PM exhibited significantly enhanced weight gain (WG), feed conversion ratio (FCR), and survival compared to those fed with the diet devoid of FM. As survival was poor across all treatments and different densities could mask growth results the trial was repeated. In Trial 2, shrimp (0.85 g, 15 shrimp/tank, n = 4) were offered diets for 6 wk. Dietary supplementation of PM at 6% significantly improved WG, FCR, and apparent net protein retention in contrast with the treatment devoid of FM, confirming the same trends in Trial 1. No significant difference was detected in protein, lipid, moisture, and mineral profiles of whole‐body shrimp as well as survival across all the treatments. Results of this study indicate that PM is a good high protein source in shrimp feeds, which can be included up to 6% in the low FM‐based diet without compromising the growth of shrimp.     

Efficacy of Three Methionine Sources in Diets for Pacific White Shrimp, Litopenaeus vannamei

Abstract.— To examine the need for supplemental dietary methionine and to determine the ability of different methionine sources to meet this need for Pacific white shrimp, Litopenaeus vannamei, a growth trial was conducted. A control diet (30% crude protein) was formulated to be deficient in methionine by inclusion of high levels of dehulled, solvent‐extracted soybean meal and with no fish meal (methionine level was 0.45% of diet as fed, 1.5% of total amino acids). Three test diets were manufactured based on the control diet but supplemented with l ‐methionine, dl ‐methionine, or an analog of methionine (2‐hydroxy‐4‐methylthio butanoic acid [HMTBA], calcium salt) at the level of 0.5% as fed (equivalent to 1.5% of total amino acids). Cystine was constant among these diets at 0.5% of diet as fed. A commercial feed (30% crude protein) was included as a reference. The culture vessels were flat‐bottomed, cylindrical, black fiberglass tanks (1.5‐m diameter) initially filled with 1000 L seawater and supplied with aeration and seawater from a well at a rate of 2 L/min. At the end of the trial, all surviving shrimp were counted and weighed. The trial was run outdoors, with a mean water temperature of 25.9 C. The mean survival, final weight, growth rate, and feed efficiency of shrimp in the control group were 95.9%, 10.8 g, 0.93 g/wk, and 0.44 g/g, respectively. The mean values of all the test treatments were 96.9%, 11.6 g, 1.00 g/wk, and 0.47 g/g, respectively. The final weight and growth rate of shrimp fed the control diet were significantly lower than those of shrimp fed the methionine‐supplemented diets, indicating that this species has a requirement for dietary methionine. There were no significant differences (P > 0.05) in any of the parameters among the test treatments, indicating that l ‐methionine, dl ‐methionine, and HMTBA can be used to meet the methionine requirement of this species under these experimental conditions. It is concluded that the three sources of methionine examined in this trial, l ‐methionine, dl ‐methionine, and HMTBA, are similar in their ability to meet the methionine requirement of this species.     

Digestibility of Glandless Cottonseed Protein in Diets for Pacific White Shrimp,Litopenaeus vannamei

Accurate digestibility coefficients for protein, energy, and lipid are needed by feed formulators to optimize diets to meet nutritional requirements and to substitute ingredients cost‐effectively. Of particular interest is protein, which accounts for the majority of shrimp feed content and expense. The current study evaluated seven cottonseed meal and protein products. Most of the samples were derived from a glandless cotton variety that lacks significant levels of the antinutritive compound, gossypol. The various protein fractions were evaluated for apparent crude protein, crude lipid, and energy digestibility when fed to juvenile Pacific White Shrimp, Litopenaeus vannamei. Apparent energy digestibility for the protein fractions derived from the glandless seed ranged from 76.7% for ground kernels to 94.6% for protein isolate, and these values were greater than the value obtained for the commercial meal that contained gossypol (64%). Apparent protein digestibility for the six glandless‐cotton‐based samples varied from 72.3% for the ground full‐fat kernels to 94.1% for the protein isolate, and these values were mostly higher than the value obtained for the commercial meal (82.3%). The high apparent digestibility values demonstrate that low‐gossypol cottonseed protein products may be useful as a cost‐effective replacement for more expensive protein sources in L. vannamei diets.     

Performance of Pacific White Shrimp,Litopenaeus vannamei,Reared in Zero‐Exchange Tank Systems Exposed to Different Light Sources and Intensities

The development of biofloc production technology has generated significant commercial and research interest directed toward the inland culture of Pacific white shrimp, Litopenaeus vannamei. Most work to date has been conducted in greenhouses, where photoautotrophic organisms are significant contributors to system functionality. In more temperate locations, operations in insulated buildings would reduce heating costs. This experiment was designed to evaluate the effect of light on shrimp cultured in intensive biofloc systems. A 92‐d experiment was conducted in 3.8‐m³ tanks. There were five light treatments: (1) natural sunlight (SUN) as a control (midday: 718 lx); (2) one metal halide light (MHL) (1074 lx); (3) one fluorescent light (1FL) (214 lx); (4) two fluorescent lights (2FL) (428 lx); and (5) three fluorescent lights (3FL) (642 lx). Artificial light treatments operated on a 12:12 daily cycle. There were three replicate tanks per treatment and each was separated by black plastic to prevent light transmission between replicates. Each tank was stocked at 465 shrimp/m² of tank bottom (initial mean weight = 0.4 g). Light treatment had a significant (P≤ 0.05) impact on average individual weight, survival, harvest yield (kg/m²), and feed conversion ratio (FCR). Harvest yield and survival among shrimp in the SUN, MHL, and 1FL treatments were not significantly different. However, there was an inverse linear relationship (P≤ 0.05; R² = 0.76) between the number of fluorescent fixtures and survival, which was related to greater concentrations of filamentous bacteria as the intensity of fluorescent light increased, causing gill fouling. Natural light and MHL did not result in high concentrations of filamentous bacteria. These results indicate that natural light, metal halide lighting, and/or relatively low levels of fluorescent lighting are suitable for indoor production of Pacific white shrimp in biofloc systems. Light spectrum and intensity can affect bacterial community structure, which has a profound effect on shrimp survival and production.     

Use of Grain Distillers Dried Yeast in Practical Diets for Juvenile Pacific White Shrimp,Litopenaeus vannamei

Grain distillers dried yeast (GDDY) is a yeast‐based protein source that is obtained from the bioethanol industry. A range of yeast‐based products has been evaluated as nutritional supplements in fish diets, yet there is limited information in shrimp. Therefore, the objective of this study was to evaluate the production response of Litopenaeus vannamei fed diets containing increasing levels of GDDY in two growth trials. In trial 1, five diets formulated to contain 360 g/kg crude protein, 80 g/kg lipids, and up to 300 g GDDY/kg were evaluated under laboratory conditions with juvenile shrimp (1.90 ± 0.10 g, initial weight). In trial 2, juvenile shrimp (0.40 ± 0.01 g, initial weight) were fed similar diets where lysine was supplemented in diets with high levels of GDDY (200 and 300 g/kg of diet). The results from this study demonstrate that inclusion of GDDY up to 300 g/kg of diet did not cause negative effects on final biomass, mean final weight, feed conversion ratio, and survival. Furthermore, the addition of lysine to diets with high levels of GDDY (200 and 300 g/kg of diet) did not enhance growth performance under the reported conditions, confirming lysine was not limiting. Consequently, these results indicate that up to 300 g GDDY/kg of diet can be used in practical diets for L. vannamei in a clear water system.     

Effects of Potassium, Magnesium and Age on Growth and Survival of Litopenaeus vannamei Post-Larvae Reared in Inland Low Salinity Well Waters in West Alabama

Abstract— The production of Litopenaeus vannamei in inland low‐salinity well water is a growing industry in several regions of the world. The state of Alabama in the southeastern USA is one such region with a large saline aquifer that could be utilized for shrimp culture. However, some farmers are experiencing problems rearing marine shrimp while others are having considerable success. Previous work has correlated low levels of potassium andor magnesium to poor shrimp survival. The problem is further complicated by the fact that the age at acclimation may also influence survival. In our present study, we evaluated the effects of potassium, magnesium, and the age of acclimation on growth and survival of PL at two farms. The first experiment was run in a static system utilizing four replicate tanks per treatment. Fifty PL₁₇ (0.0066 g) that had been acclimated to 4 ppt seawater were stocked into each tank and the following treatments evaluated: low salinity well water (LSWW) without mineral supplements, LSWW with KCl, LSWW with MgCl₂, and LSWW with KCl and MgCl, added to the water. Shrimp were harvested, counted and weighed after 4 wk. Survival was significantly higher in treatments receiving mineral supplements whereas biomass was only higher in the two treatments with potassium supplements. The second experiment was set up initially as a static system filled with 8.5‐ppt reconstituted sea water that was then converted to a flow‐through system using LSWW. This experiment evaluated the effect of PL age at acclimation on survival and growth at four different ages (PL₁₅, PL₁₉, PL₂₃, and PL₂₇). All tanks were stocked with 50 PL₁₃L. vannarnei. Two days after stocking, and then at 4‐d intervals, a series of four tanks were converted to flow through (rate of 40 Lhr) using LSWW. After acclimation, water flow was maintained in all tanks until 28 d after stocking when tanks were harvested and surviving shrimp were counted and weighed. Survival and growth increased with PL age when shrimp were acclimated to inland low salinity well water.     

Effects of Dietary Carbohydrase Supplementation on Performance and Apparent Digestibility Coefficients in Pacific White Shrimp,Litopenaeus vannamei

A growth trial and a digestibility trial were conducted to evaluate the efficacy of carbohydrase supplemented to practical shrimp feeds. The 5‐wk growth trial investigated the effects of carbohydrase supplementation at 0, 0.01, 0.02, 0.03, 0.04, and 0.05% in soybean‐based diets on the performance of juvenile Pacific white shrimp, Litopenaeus vannamei. No significant differences were observed in final biomass, final mean weight, weight gain, feed conversion ratio, and survival across all treatments. The digestibility trial was conducted to evaluate the effects of carbohydrase supplementation at 0.02%, which is the recommended dose by the company that developed the carbohydrase on apparent digestibility coefficients of dry matter, protein, and energy of Pacific white shrimp. Protein digestibility was significantly improved when fed diets contained 0.02% carbohydrase in contrast with the basal diet. No significant differences were found in apparent digestibility coefficients of dry matter and energy. Based on the positive results on protein digestibility, further research regarding the efficacy of exogenous enzymes and their application is warranted.     

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     

Tail Muscle Free Amino Acid Concentration of Pacific White Shrimp,Litopenaeus vannamei,Fed Diets Containing Protein‐bound versus Crystalline Amino Acids

Tail muscle tissue free amino acids (FAA) concentration is reported for subadult (4.3 g) Litopenaeus vannamei fed diets containing only protein‐bound amino acids, crystalline lysine as a supplement to protein‐bound lysine, and only crystalline amino acids (CAA). FAA were determined in shrimp at 0.00, 0.25, 0.5, 1, 2, 4, and 8 h postfeeding. Highest total tissue concentrations of essential amino acids and individual amino acids were typically observed 4 h postfeeding for shrimp fed intact and crystalline lysine‐supplemented feeds. Those shrimp offered diets containing only CAA showed no tissue maxima. Similar uptake patterns for lysine shown by shrimp fed the intact and crystalline lysine‐supplemented diet indicate the potential use of small amounts of crystalline lysine in shrimp feeds.     

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。     

凡纳滨对虾感染白斑综合症病毒后的新症状

2007年6-7月,辽宁营口地区凡纳滨对虾养殖场陆续出现死虾现象,通过组织病理观察和PcR检测,确定为白斑综合症.患病初期,对虾并未表现出典型白斑、甲壳易剥离等症状,而在鳃区头胸甲内侧滋生一种囊状胶状物,导致头胸甲内侧肿胀,病理观察发现该滋生物为对虾感染白斑综合症病毒后,皮下组织"胶质化"的结果,同时胃和皮下组织的结缔组织中有大量的典型性病变核;细菌分离结果显示,伴随着弧菌和假单胞菌的混合感染.     

凡纳滨对虾α-淀粉酶基因的SNPs检测

利用PCR产物直接测序法,对凡纳滨对虾SPR和SPF 2个品种共40个样本的α-淀粉酶基因(GenBank序列号:AJ133526)的单核苷酸多态性(SNP)进行了研究。找到9个SNPs,分别为:C127T、A138G、T951C、T1083C、C1457T、A2147C、A2226G、A2297G和T2306C。其中1个SNP是第4外显子中的错义突变,2个SNPs分别是第5和第7外显子中的同义突变,6个SNPs是内含子中的突变。这些结果可为凡纳滨对虾的研究提供遗传学依据。     

Magnesium Budget for Inland Low‐Salinity Water Shrimp Ponds in Alabama

A magnesium budget was prepared for a commercial low‐salinity shrimp farm in the Blackland Prairie region of Alabama for one production cycle. Ponds had previously been used for production and fertilized with magnesium; two ponds (S‐5 and S‐6) for four previous years and one pond (N‐9) for one previous season. Fertilization with sulfate of potash magnesia (K₂SO₄·2MgSO₄ or K‐Mag^®) was applied to these ponds to obtain the concentrations of 20 mg/L, averaging 1274 kg Mg²⁺/ha. Additional inputs of magnesium included groundwater, rainfall, and runoff averaged 441.5 kg/ha. A water budget for ponds indicated that 292.6 kg/ha of magnesium in outflows. The difference in inputs and magnesium outputs resulted mainly from adsorption of magnesium by pond bottom soils. However, the increase in exchangeable magnesium in the upper 15‐cm layer of pond bottom soils was not great enough to account for the difference in total magnesium inputs and magnesium outputs in water and shrimp. Possible explanations for this discrepancy are magnesium precipitation, nonexchangeable fixation of magnesium by clay minerals, incomplete extraction of magnesium, and analytical error. The decreased uptake of magnesium by older ponds, S‐5 and S‐6, indicate that the soils had a diminishing affinity for the cation or an equilibrium concentration is being established.     

Sperm Quality Over Consecutive Spermatophore Regenerations in the Pacific White Shrimp Litopenaeus vannamei

The reproductive potential of males plays an important role in the productivity of captive penaeids. Males present a large variability in their reproductive potential, and thus the selection of appropriate males for reproduction is highly desirable. The present study compares sperm quality at the beginning of the experiment (baseline values) with variations in sperm quality as a result of consecutive spermatophore regenerations. This was done to evaluate possible predictive criteria for optimal sperm quality based on morphological and biochemical criteria in pond-reared Pacific white shrimp Litopenaeus vannamei males. Sperm quality was similar between left and right spermatophore. Sperm count and proportion of normal sperm increased by 86 and 65% (P < 0.05) respectively, from baseline values to third spermatophore regeneration. Proportion of dead sperm progressively decreased with consecutive regenerations, attaining values 33% lower by the third regeneration, compared to baseline values. This indicates that no decrease in sperm quality occurs in L. vannamei during consecutive regenerations and that the existing spermatophores at stocking of males should be expelled to have higher sperm quality in regenerated spermatophores. Furthermore, this procedure allows selecting individuals with high baseline sperm quality based on significant correlations between baseline and regenerated sperm quality observed in the present work. Baseline values of glucose concentration in the hemolymph were positively correlated to baseline values of sperm count (r = 03, P < 0.05). In contrast, baseline values of several lipids in the hemolymph were negatively correlated to several traits of sperm quality at first sampling (baseline values) or at first regeneration. These results are discussed in terms of nutritional requirements of males and of possible predictive criteria of sperm quality.     

Nitrogen and Phosphorus Dynamics in the Biofloc Production of the Pacific White Shrimp,Litopenaeus vannamei

A study evaluating nitrogen and phosphorus dynamics was carried out using biofloc technology (BFT) systems employed to raise Litopenaeus vannamei juveniles. The study was carried out for 42 d in three fiberglass tanks with 210 L useful volume with no water exchange. Salinity, temperature, dissolved oxygen, pH, nutrients, suspended solids, and chlorophyll‐a were monitored every 3 d. At the completion of the experiment, the shrimp had absorbed 39.1 and 35.0% of the total nitrogen (N) and phosphorus (P) inputs, respectively, while 39.0% of the N and 34.1% of the P remained in the system in dissolved forms. The dominant process of ammonium immobilization in the system was oxidation by nitrifying bacteria. On Day 42, the nitrate concentration represented more than 80% of the total dissolved inorganic nitrogen in all tanks. However, most of the dissolved nitrogen present in the tanks (80%) was organic. Phosphate and organic nitrogen and phosphorus continuously accumulated in the system throughout the experiment. The removal of these nutrients should be the focus of future studies because they may enhance the growth of harmful algae in tanks and in the water bodies that collect the post‐crop wastewater.     

凡纳滨对虾白便综合征的组织病理学观察

本文比较观察了不同规格的健康和患白便综合征凡纳滨对虾Litopenaeus vannamei肝胰腺、中肠、后肠、后盲囊等的组织结构。组织病理显示:白便综合征凡纳滨对虾肠道严重病变,肠腔空,环肌两侧增生大量成纤维细胞,这些增生细胞取代了肠上皮,而不见正常柱状上皮细胞;肝胰腺有不同程度和性质的病变,如腺管萎缩、崩解、坏死等。凡纳滨对虾患白便综合征的组织病变演变过程为:最初肠上皮基膜下出现一圈增生细胞,肠上皮柱状细胞脱离基膜;增生细胞持续增生增多,肠上皮崩解脱落至肠腔,增生细胞完全取代肠上皮;增生细胞不断增生,增生细胞层逐渐变厚,随着时间的推移,增生细胞层近腔端的一圈增生细胞坏死,出现一圈棕黄色物质,最终坏死细胞连同棕黄色物质脱落至肠腔。脱落至肠腔的腺管细胞、上皮细胞、增生细胞排出体外即为肉眼可见的白便。     

饲料中添加虾青素对凡纳滨对虾生长、存活和抗氧化能力的影响

从雨生红球藻中提取虾青素,以不同质量浓度(0、20、40、60、80、100 mg/kg)添加到凡纳滨对虾的饲料中投喂7周,研究虾青素对凡纳滨对虾生长、存活和抗氧化能力的影响.结果显示,虾青素可提高凡纳滨对虾的存活率和特定生长率,其中添加量80 mg/kg组最高,80 mg/kg组特定生长率和对照组间差异显著(P<0.05),但试验组和对照组间存活率无显著差异(P>0.05).各试验组的总抗氧化能力与对照组相比显著升高(P<0.05),至第4周后逐步稳定;超氧化物歧化酶活力和过氧化氢酶活力与对照组相比均显著降低,且均表现出先降后升的变化趋势,第4周酶活力降至最低.以生长、存活和抗氧化能力为指标,虾青素的最适添加量为80 mg/kg,最佳投喂时间为4周.