A review of the current (1992) state of our knowledge concerning reproduction in open thelycum Penaeid shrimp with emphasis on Penaeus vannamei

Summary

The current state of knowledge relating to the reproduction of the commercially important open thelycum shrimps (Crustacea: Penaeidae) is reviewed with particular reference to Penaeus vannamei. Industry standard procedures for the breeding of shrimps in captivity are reviewed against a background of knowledge concerning the maturation processes in males and females. The factors controlling maturation are not completely understood, and it is not clear whether maturation of females is size-or age-dependent. Although unilateral eyestalk ablation is routinely used to induce maturation, the physiological mechanism of this operation is not properly understood. Further research on environmental conditions for successful maturation is required. Nutrition is an important component in successful artificial breeding programs that still rely on the provision of natural foods (squid and polychaeta). The processes of oocyte formation, mating, spawning and hatching are discussed in relation to observations made at the Gulf Coast Research Laboratory.     

The role of the Y-organ and cephalic gland in ecdysteroid production and the control of molting in the crayfish,Orconectes limosus

Summary The production of ecdysteroids (monitored by RIA) by Y-organs and cephalic glands in vitro was measured and hemolymph ecdysteroid levels were determined in the crayfish,Orconectes limosus, both after eyestalk ablation and as a function of time during natural premolt. Y-organ synthesis of ecdysteroid increased in parallel with a rise in hemolymph ecdysteroid concentrations under both conditions, peaking in substage D₂ of premolt. Y-organ ecdysteroid output after eyestalk ablation was 3–4 times higher. Thus, removal of the inhibiting system of the eyestalk effectively removes not only the principal control but also any modulation of ecdysteroid secretion by the Y-organs. Ecdysteroid levels remained low in Y-organ-ectomized crayfish, although premolt was initiated in some animals. The cephalic gland does not appear to contribute to the regulation of molting inOrconectes limosus. The Y-organs, on the other hand, are a principal source of ecdysteroids which regulate the major synthetic activities of premolt.     

Electrical responses to amputation of the eye in the mystery snail

Immediately following amputation through the eyestalk of the mystery snail (Pomacea), a persistent ionic current enters the apical amputation surface of the eyestalk stump. The circuit is completed by current driven from undamaged integument of the eyestalk stump and other body regions. The current is relatively steady during the first 10 hours following amputation. Currents subsequently begin a slow decline to base line levels by 60 hours postamputation--a time coincident with wound healing processes. The "battery" driving this ionic current is the internally negative transepidermal potential existing across the snail integument--perhaps the result of a net inward pumping of chloride across the skin. This system is compared to other regeneration models such as the amphibian limb, bone fracture repair, and skin wound healing. We suggest that ionic current may be a control of eye regeneration in the snail.     

Regeneration of appendages in the large milkweed bug, Oncopeltus fasciatus

An analysis was made of the regeneration of legs and antennae of Oncopeltus. Amputations were performed on first instar larvae within 24 hr after hatching, and on later instars within 24 hr after ecdysis. The resulting regenerates were then measured at each instar. When amputations were performed soon after hatching, there was no significant effect on the duration of any instar. The regenerate was usually visible after the second post-operative ecdysis, and was smaller than a normal appendage (hypomorphic). Removal of the three distal segments of the antenna usually resulted in regeneration of only one segment which was abnormally long and showed a combination of the bristle patterns characteristic of the two most distal segments of the control. In a few such cases a partial intersegmental membrane was present in the regenerated segment. Removal of the tarsus resulted in a structurally complete regenerate which was smaller than the control tarsus. The largest leg regenerates were obtained when amputation was performed through the tibia. With amputation through the femur, a decrease in length of the remainder of this segment was observed after the first ecdysis. This type of amputation and amputation through the trochanter in some cases resulted in the formation of a globular stump containing tarsal claws. The results indicate that amputation of part of an appendage in Oncopeltus does not stimulate an increased growth rate in the stump, but merely causes reorganization of the stump material which subsequently grows at the normal rate. Since even the most hypomorphic regenerates contained well-formed claws, even though proximal parts were missing, it appears that the reorganization process must begin at the most distal point and proceed proximally.     

Methyl farnesoate induced ovarian maturation in the spider crab,Libinia emarginata

Summary

To overcome the problem of getting crustaceans to reproduce in captivity, eyestalk ablation or X-organ sinus gland removal is commonly utilized in commercially important species such as shrimp. We have investigated the effect of unilateral and bilateral eyestalk ablation on methyl farnesoate (MF) production by mandibular organs (MOs) and on ovarian maturation in female spider crabs Libinia emarginata, a useful model since these animals are in a terminal molt and are devoid of a functional Y-organ. Non-reproductive, over-wintering female L. emarginata were induced to be reproductive by feeding and increasing the holding temperature to stimulate the endocrine system. In addition, we removed X-organ sinus glands by eyestalk ablation either unilaterally (UEA) or bilaterally (BEA) to further stimulate MF synthesis by MOs. Endogenous MF in the hemolymph was extracted and quantified by means of HPLC and in some cases by GC/MS. Oocyte growth and egg quality were studied simultaneously to determine how they were related to MF levels found during vitellogenesis. The initial MF concentration in unablated controls was low, 0.31 ng/ml of hemolymph, and this increased (p<0.05) to about 1 ng/ml by 2 weeks, remaining at about that level for the remainder of the experiment. Eyestalk ablation significantly stimulated MF concentrations by week 1 to nearly 2 and 3.5ng/ml in the UEA (p <0.01) and BEA (p <0.001) animals, respectively. Oocytes appeared to respond to increased MF levels, as ovarian maturation was initiated from the point at which MF increased (p <0.05). Thereafter, the rate of oocyte growth was directly correlated with the extent of elevation of MF. The gonado-somatic index [(GSI) = gonad weight/body weight × 100] of controls at the start was about 1.5 and increased to 6.5 by week 4. Mature oocytes were reached at a GSI around 7. Oocyte maturation was accomplished at week 2 in BEA, week 3 in UEA, and later than week 4 in controls. After maturation, oocytes started to degrade in some ablated animals, particularly in the bilaterally ablated ones where the highest MF concentrations were observed. These data indicate that MF elevations are required for stimulating ovarian maturation in Crustacea. MF appears to accelerate gonad development during the vitellogenic process, but may be deleterious at high concentrations. These results have a significant and important application and implications for aquaculture.     

Comparison of two surgical techniques for mastectomy of goats

Two different techniques for mastectomy were carried out on 14 goats with gangrenous mastitis. The animals were randomly assigned to one of two groups containing seven goats each. The first group was operated via a classical surgical mastectomy technique (either bilateral (n=5) or unilateral (n=2)). The second group was operated via vascular ligation of the external pudendal blood vessels and milk vein and amputation of the affected teat (either bilateral (n=3) or unilateral (n=4)). Comparison between the two groups was carried out. Vascular ligation and teat amputation proved to be an effective, quick, safe, and less expensive technique for mastectomy in goats. Ligation of udder vasculature was less traumatic than surgical amputation and the stress on the patient was minimal.     

Induction of Ovarian Maturation and Spawning in <Emphasis Type="Italic">Penaeus monodon</Emphasis> Broodstock by Double-Stranded RNA

Ovarian maturation in crustacean is under the control of gonad-inhibiting hormone (GIH); a neuropeptide secreted from X-organ sinus gland complex in eyestalks. Unilateral eyestalk ablation that partially destroys GIH source is therefore a general practice in Penaeus monodon hatchery to induce ovarian maturation and spawning. Our previous report showed that silencing of GIH expression by GIH-specific double-stranded RNA (GIH-dsRNA) resulted in an increased expression level of vitellogenin in P. monodon, thus suggesting that GIH-dsRNA could be an alternative method to induce ovarian maturation in female P. monodon broodstock. In this study, we further demonstrated that a single injection of GIH-dsRNA into previtellogenic female P. monodon at the concentration of 3 μg GIH-dsRNA per gram body weight of shrimp was able to inhibit GIH expression for a minimum of 30 days. This dsRNA-mediated GIH silencing led to ovarian maturation and eventual spawning in both domesticated and wild female broodstock, particularly with a comparable effect to eyestalk ablation in wild shrimp. This is the first report that demonstrates a potential strategy to induce ovarian maturation in female P. monodon broodstock by GIH-dsRNA and thus provides a possible substitute for the cruel and detrimental eyestalk ablation practice.     

Dynamics of vitellogenin mRNA expression and changes in hemolymph vitellogenin levels during ovarian maturation in the giant freshwater prawn Macrobrachium rosenbergii

The dynamics of vitellogenin mRNA expression during ovarian maturation in Macrobrachium rosenbergii were examined by measuring hemolymph vitellogenin (Vg) levels and Vg mRNA expression in the hepatopancreas and ovary at differing reproductive stages in both intact and eyestalk ablated animals. Vg mRNA was quantified using real-time RT-PCR and hemolymph Vg was measured by enzyme immunoassay. In intact animals, Vg mRNA levels in the hepatopancreas and hemolymph Vg levels showed a gradual increase during the molt cycle concomitant with increasing gonadosomatic index (GSI), with Vg levels decreasing prior to ecdysis although GSI continued to increase. Eyestalk ablation was seen to accelerate Vg synthesis as well as ovarian maturation, although it did not alter the overall pattern of Vg expression. Vg mRNA expression was negligible in the ovary of both intact and eyestalk ablated animals, confirming that the hepatopancreas is the principal site of Vg synthesis in M. rosenbergii with the ovary being only a minor contributor. This study has shown that Vg synthesis is correlated to ovarian maturation and the molt cycle in M. rosenbergii.     

超声引导下外周神经阻滞对老年下肢动脉硬化闭塞症截肢术患者循环系统和疼痛的影响

目的:研究超声引导下外周神经阻滞对老年下肢动脉硬化闭塞症截肢术患者循环系统和疼痛的影响。方法:选择我院2016年2月～2019年11月收治的82例老年下肢动脉硬化闭塞症患者为研究对象,所有患者均接受下肢截肢术治疗,对照组采用硬膜外麻醉,研究组采用超声引导下外周神经阻滞。对比两组感觉神经、运动神经阻滞情况、阻滞效果,循环功能,疼痛指标和不良反应。结果:研究组感觉神经及运动神经阻滞起效时间较对照组短,感觉神经及运动神经阻滞维持时间较对照组长,差异比较有统计学意义(P0.05)。两组优良率差异比较无统计学意义(P0.05)。手术开始30 min时,对照组心率、平均动脉压均下降,研究组无明显改变,差异比较有统计学意义(P0.05)。术后24h时,两组疼痛指标浓度均较入室时增加,研究组低于对照组,差异比较有统计学意义(P0.05)。研究组不良反应总发生率低于对照组(P0.05)。结论:老年下肢动脉硬化闭塞症截肢术患者予以超声引导下外周神经阻滞的起效时间更快,能够减轻围术期疼痛,保持术中循环功能的稳定。     

Metabolic effects of eyestalk removal in the crab Varuna litterata (Fabricius)

Metabolic effects of eyestalk removal in the crab V. litterata is studied. Bilateral eyestalk ablation results in hypoglycaemia and a fall and rise in the glycogen content of hepatopancreas and muscle respectively. Injection of unboiled eyestalk extract evokes hyperglycaemia, whereas boiled eyestalk extract does not produce any significant change in the glycaemia level. The other effect of eyestalk removal is a fall in the fat content of the hepatopancreas and these results are discussed.     

Infection of adult migratory river shrimps,Macrobrachium ohione,by the branchial bopyrid isopod Probopyrus pandalicola

Abstract. Macrobrachium ohione is a migratory (amphidromous) river shrimp (Decapoda, Caridea) that may be parasitized by the branchial parasite Probopyrus pandalicola (Isopoda, Bopyridae). The parasite disrupts gonadal maturation and spawning in female shrimps, resulting in the total loss of reproduction. Shrimps are usually infected by bopyrid parasites during the late zoeal or early postlarval stages; in this study, we investigated the apparent parasite infection of adult shrimps. We analyzed the relationships between parasite body size (total length) and host shrimp body size (carapace length) to test the hypothesis that parasite infection of adult shrimps occurs during the shrimps' reproductive migrations. The results presented here indicate that infection of adult shrimps is common in M. ohione in the Atchafalaya and Mississippi Rivers, Louisiana, USA. In the two upriver sites sampled, Butte La Rose (BLR) and River Bend (RB), parasite size was not associated with host body size. In these locations, many parasitized adult M. ohione were infected with immature P. pandalicola (40.3% in BLR and 51.2% in RB), indicating that the shrimps were adults at the time of infection. A possible explanation is that when female shrimps enter the estuary to hatch larvae, they molt and spawn another brood. The smaller male shrimps that accompany the females downstream are also assumed to molt and continue growth. The intermediate host of the parasite is an estuarine copepod, and thus the parasite cryptoniscus larva that infects the host shrimp is primarily estuarine as well. Newly molted shrimps have soft cuticles, which may facilitate their infection by parasite cryptonisci. Our conclusion is that most infections of adult shrimps occur during their migration into estuarine waters, the primary habitat of infective parasite larvae, and that host vulnerability is probably increased following host ecdysis.     

Comparison of the effect of stem cell therapy and percutaneous transluminal angioplasty on diabetic foot disease in patients with critical limb ischemia

Background aimsThe aim of our study was to compare the effect of autologous stem cell therapy (SCT) and percutaneous transluminal angioplasty (PTA) on diabetic foot disease (DFD) in patients with critical limb ischemia (CLI).MethodsThirty-one patients with DFD and CLI treated by autologous stem cells and 30 patients treated by PTA were included in the study; 23 patients with the same inclusion criteria who could not undergo PTA or SCT formed the control group. Amputation-free survival, transcutaneous oxygen pressure (TcPO₂) and wound healing were assessed over 12 months.ResultsAmputation-free survival after 6 and 12 months was significantly greater in the SCT and PTA groups compared with controls (P = 0.001 and P = 0.0029, respectively) without significant differences between the active treatment groups. Increase in TcPO₂ did not differ between SCT and PTA groups until 12 months (both Ps < 0.05 compared with baseline), whereas TcPO₂ in the control group did not change over the follow-up period. More healed ulcers were observed up to 12 months in the SCT group compared with the PTA and control groups (84 versus 57.7 versus 44.4 %; P = 0.042).ConclusionsOur study showed comparable effects of SCT and PTA on CLI, a major amputation rate that was superior to conservative therapy in patients with diabetic foot and an observable effect of SCT on wound healing. Our results support SCT as a potential promising treatment in patients with CLI and diabetic foot.     

Function of an eyestalk ganglion,the Medulla terminalis,in olfactory integration in the lobster,Panulirus argus

Summary Ipsilateral antennular dysfunction resulting from total unilateral eyestalk ablation in spiny lobsters does not occur when visual input is restricted by an opaque cap over one eyestalk, or when optic ganglia alone (eg. lamina ganglionaris, medulla externa, medulla interna) are removed. Antennular dysfunction appears only when connections between the most proximal of the four eyestalk ganglia, the medulla terminalis, and the remainder of the cerebral ganglia (brain) are interrupted. We conclude that neural processing of olfactory input from the antennule involves structures in the medulla terminalis.Contribution number 430 from the Bermuda Biological Station for Research, Inc. This work was supported by USPHS Grant NB-06017.     

Effects of eyestalk ablation on growth and food conversion efficiency of the freshwater prawn Macrobrachium lanchesteri (de Man)

Bilateral eyestalk ablation in the freshwater prawn Macrobrachium lanchesteri results in high mortality, while unilateral eyestalk ablated prawns exhibited a high survival rate. There was marked increase in the growth of bilateral eyestalk-ablated prawns (47.70 mg/prawn) as compared to those that were unilaterally ablated (19.19 mg/prawn).     

Effect of gonadotropin-releasing hormone and prostaglandin F2α on reproduction in postpartum dairy cows

Thirty dairy cows serving as the treated group (Group A) were injected intramuscularly with 100 mcg gonadotropin-releasing hormone (GnRH) at 10 to 16 days postpartum followed by 25 mg prostaglandin F₂α (PGF₂α) 14 days later. Twenty-nine herdmate dairy cows (Group B) serving as controls were treated in a similar manner using saline injections rather than GnRH or PGF₂α treatments. Only cows without obvious uterine infection were assigned to the experimental groups, and any uterine pathology that developed during the treatment interval was treated accordingly following the experimental period. Internal genitalia were evaluated via rectal palpation prior to each injection. Blood samples were collected for progesterone analysis before each injection and at 30 hours following the PGF₂α or the second saline injection. Experimental animals were artificially inseminated at the first detected postpartum estrus starting 35 to 40 days following calving. Results indicated evidence of enhanced cyclicity when Group A cows were compared with those in Group B. However, there were no significant differences between the two groups for interval to first observed estrus, interval to first serive, first serive pregnancy rate, services per pregnancy and days open. Furthermore, no difference in the incidence of follicular or luteal cysts, incidence of repeat breeders or number of reproductive culls was observed. From observations in this study, the GnRH and PGF₂α treatment scheudule might not be economically beneficial in lactating dairy cows as long as reproductive tract abnormalities are promptly diagnosed and subsequently treated by the attending practitioner.     

Morphological variations among larval-postlarval intermediates produced by eyestalk ablation in the snapping shrimp Alpheus heterochaelis Say

The eyestalk of many crustaceans contains the X-organ, the presumptive site of production and release of many protein and peptide hormones into the hemolymph. Removal of the eyestalk deprives the animal of these hormones and is known to affect many physiological processes in the adult and developing larva. In the snapping shrimp Alpheus heterochaelis Say, eyestalk ablation performed early in larval development has profound effects on morphogenesis, causing the appearance of supernumerary larval stages, accompanied by retardation and even complete arrest of morphogenesis. In this study, we examined the effects on morphogenesis of bilateral eyestalk removal at carefully controlled intervals. We found that the crucial point for this operation-the point at which the animal attains the ability to metamorphose fully-is just before the onset of ecdysis to the third instar. Additionally, the pattern of development and morphogenesis among body segments follows a discernible double gradient pattern along the anterior-posterior axis in which the extremities of the animal attain the potential for morphogenetic advance prior to the central thorax. This pattern of morphogenesis, punctuated by ecdysis, is a continuous rather than a stepwise or compartmentalized phenomenon.     

Identification of steroid hormones and fatty acids during gonadal maturation of spiny lobster Panulirus homarus

Information on steroid hormones and fatty acids that play roles in lobster reproduction is still very limited although the data are indispensable to seed production in hatchery. The study was designed to identify steroid hormones and fatty acids during gonadal maturation of spiny lobster (Panulirus homarus). Male spiny lobsters were treated with and without thyroxine injection. Female spiny lobsters were treated with and without eyestalk ablations during mature and immature gonad developments. Androst-5-en-17-one,3β (androst) and estran-3-one,17β (estran), two steroid hormones were identified at different levels of gonadal maturity of spiny lobsters. High concentrations of androst and estran were detected in the male spiny lobsters treated with thyroxine injections. Estran showed high concentrations in female brood stock of spiny lobsters during oogenesis stages both without eyestalk ablation and with ablation of one or two eyestalks, except in the immature female gonads. It was found that stearic acid was the highest and dominant fatty acid in mature male spiny lobster. Stearic acid, oleic acid, palmitic acid and caprylic acid were fatty acids with high concentrations in immature and mature female spiny lobsters. After 30 days in captivity, only stearic acid and oleic acid were found dominantly in eyestalk ablated mature female spiny lobsters.     

Effect of bilateral eyestalk ablation on ovarian development and moulting in early and late intermoult stages of female spiny lobster Panulirus homarus (Linnaeus, 1758)

Abstract

The present study describes the effect of bilateral eyestalk ablation (BESA) on reproduction and moulting of spiny lobster Panulirus homarus females in their early and late intermoult stages. The lobsters obtained from the wild were conditioned for the experiment. The experiments were conducted at the Calicut research centre of Central Marine Fisheries Research Institute, India. Eyestalk ablation of females was done by ligation. The responses of the bilaterally eyestalk-ablated lobsters were statistically analysed. BESA conducted on the early and late intermoult stages resulted in the simultaneous acceleration of the somatic growth and reproductive processes with higher emphasis for oogenesis in lobsters ablated in the early intermoult phase and comparatively lower activity in those ablated in the late intermoult phase. Ablation in late intermoult phase resulted in faster entry into the premoult stage compared to the control.     

Inhibition of Alveoloar Bone Loss During Maturation of the Rat

The effects of dichloromethylene diphosphonate (C1₂MDP) on previously described maturational bone loss were quantified in 24 Wistar rats. Four groups of six animals each were treated daily from 18 to 28 weeks of age with a subcutaneous injection of a 0.1, 1.0 or 10mg/kg dose of C1₂MDP or were sham treated with 0.9% NaC1. Prior to sacrifice, all animals were double-labeled with tetracycline. The interdental bone between first and second maxillary molars was evaluated on decalcified stained sections and on undecalcified ground sections by digitizing morphometry. No significant differences in periodontal ligament width, bone height, osteoclast numbers or tetracycline labeled surface were detected. Significantly greater bone area (p<0.01) and bone width (p<0.005), and significantly fewer osteoblasts/mm of bone surface (p<0.001) were measured in rats treated with 10 mg/kg doses of C1₂MDP; and a dose response was demonstrated. It was concluded that C1₂MDP prevented interdental bone loss by inhibiting bone resorption, and that bone formation may have been indirectly reduced through a coupling mechanism.