Effect Of Unilateral Eyestalk Ablation Research Articles

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Participation of calmodulin in ovarian maturation induced by eyestalk ablation in red swamp crayfishProcambarus clarkii

Eyestalk ablation is involved in the ovarian development and maturation of crustaceans held in captivity. However, the molecular mechanism of eyestalk ablation induction of ovarian maturation remains unclear. Reports show that calmodulin (CaM) transduces Ca2+ signals into downstream effects, which is a potent critical factor in the induction course of Penaeus monodon. The effects of unilateral eyestalk ablation on the ovarian growth and maturation of domesticated female Procambarus clarkii were investigated in this study. The expression patterns of CaM gene during the maturation course induced by eyestalk ablation were analysed using reverse-transcriptase quantitative PCR. RNA interference technique was used to elucidate the role of CaM in the crayfish eyestalk ablation mechanism to induce ovarian maturation. The results demonstrated that the expression level of CaM was significantly induced to 8.7-fold 1 day after the eyestalk ablation (P < 0.05), and then gradually reduced on the following days. The CaM knockdown which is lethal to crayfish inhibited the ovarian maturation induced by eyestalk ablation. Thus, the CaM calcium signalling pathway is important in the induction of ovarian maturation by eyestalk ablation in crustaceans.

The Effects of Eyestalk Ablation on the Reproductive and Immune Function of Female Macrobrachium americanum

Eyestalk ablation is the most common procedure used to induce crustacean reproduction in commercial hatcheries. However, other physiological and metabolic processes are affected by the removal of the X-organ sinus gland complex located in the eyestalk. In this study, the effect of unilateral eyestalk ablation on the concentration of several hemolymph metabolites, reproduction and immune function in female Macrobrachium americanum was investigated. Molting cycle time was not significantly (P=0.17) shortened in eyestalk-ablated females. However, an increased number of molts was observed in the eyestalk-ablated group because survival was significantly higher due to increased passivity and lowered aggression. As M. americanum has closed thelyca, reproduction was not accelerated after eyestalk ablation compared to control prawns. Food intake (P=0.007) and oxygen consumption (P=0.047) were both higher in eyestalk-ablated females. Concentrations of protein and glucose in hemolymph were not affected (P=0.54 and P=0.19, respectively), indicating that the demand for these metabolites was met. Glucose was metabolized by aerobic metabolism as shown by the lower lactate concentration (P=0.02) and higher respiration rate after ablation. Protein was metabolized for growth as revealed by the 100% higher growth rate in eyestalkablated females (P=0.017). Triglycerides were more highly concentrated (P=0.02) in eyestalk-ablated females. This difference was most likely due to being transported from the digestive gland to the gonad.By analyzing the immune system it was observed that only the total hemocyte count was higher (P=0.002) in eyestalk-ablated females. The protein content in hemocytes, the prophenol oxidase system and the coagulation time were not affected. In conclusion, the eyestalk ablation procedure did not cause female M. americanum to have more reproductive events over time. Despite this failure to accelerate reproduction, eyestalk ablation reduced aggression, and thus increased survival, and promoted superior growth. This result suggests that eyestalk ablation is promising for the cultivation of M. americanum.

Effect of Unilateral Eyestalk Ablation on the Biochemical Composition of Commercially Important Juveniles of Macrobrachium malcolmsonii (H. Milne Edwards)

Effect of Unilateral Eyestalk Ablation on the Biochemical Composition of Commercially Important Juveniles of Macrobrachium malcolmsonii (H. Milne Edwards)

Effect of Unilateral Eyestalk Ablation and Diets on the Growth of Freshwater Prawn Juveniles of Macrobrachium malcolmsonii (H. Milne Edwards)

Effect of Unilateral Eyestalk Ablation and Diets on the Growth of Freshwater Prawn Juveniles of Macrobrachium malcolmsonii (H. Milne Edwards)

Effect of Unilateral Eyestalk Ablation on the Biochemical Changes of Edible Portunid Crab Charybdis lucifera (Fabricius)

Effect of Unilateral Eyestalk Ablation on the Biochemical Changes of Edible Portunid Crab Charybdis lucifera (Fabricius)

The effect of unilateral eyestalk ablation and diet on the reproductive performance of wild-caught Farfantepenaeus aztecus (Ives, 1891) using a closed recirculating maturation system

Two studies were conducted to evaluate the effects of unilateral eyestalk ablation and diet on the reproductive performance of wild populations of Farfantepenaeus aztecus. In both studies, females in two treatments were unilaterally ablated while those in the control treatment were not. Shrimp in the non-ablated treatment and one of the unilaterally ablated treatments received frozen bloodworms (8% BW day−1) and frozen squid (12% BW day−1). The bloodworm component of the diet of the third unilateral ablation treatment was replaced with frozen adult enriched Artemia sp. Ablated female population spawning per night, in both studies, was higher than non-ablated spawning (8.5 and 8.9 vs. 2.6%; 7.4 and 7.5 vs. 2.7% respectively; P<0.05). Replacement of bloodworms with adult enriched Artemia sp. had no negative effect on the number of eggs spawned per ablated female (124 000 vs. 115 000 eggs spawn−1; 144 000 vs. 151 000 eggs spawn−1 respectively; P>0.05). The life span of ablated females fed adult enriched Artemia sp. was 8 and 40 days longer than ablated females fed bloodworms for the first and second studies respectively. Replacement of bloodworms with adult enriched Artemia sp. resulted in higher hatch and larval survival rates (Nauplius 1 to Zoea 1) (55.0% vs. 46.9% and 44.8% vs. 37.2%), respectively, P<0.05.

Reproduction and molt in previously spawned and first-time spawning red-claw crayfish Cherax quadricarinatus females following eyestalk ablation during the winter reproductive-arrest period

The effect of unilateral eyestalk ablation on reproduction, molting and quality of offspring was investigated in Cherax quadricarinatus females during the reproductive-arrest period (winter). At the end of the Autumn, females that had spawned for the first time had relatively uniform, early vitellogenic ovaries, while most females that had spawned previously had ovaries containing two distinctly sized and coloured oocyte populations. These included one population of small oocytes, similar to oocytes found in first-time spawners, while the other comprised of large oocytes. Winter reproduction of females that had spawned previously was not affected by eyestalk ablation, whereas significantly increased spawning activity was observed in eyestalk-ablated first-time spawners. Both females that had spawned previously and first-time spawners that were eyestalk ablated molted significantly more frequently than intact females. The size and number of offspring were not affected by eyestalk ablation. These results show that small synchronous oocyte populations were affected by eyestalk ablation while large oocytes were not affected; females with single-sized-oocyte ovaries tended to be more receptive to the treatment. Unilateral eyestalk ablation may present a solution for induction of spawning only in young females and perhaps in synchronized broodstock.

Social control of growth in Macrobrachium rosenbergii. V. The effect of unilateral eyestalk ablation on jumpers and laggards

The effect of unilateral eyestalk ablation on Macrobrachium rosenbergii juveniles classified according to their relative rank was investigated. Jumper and laggard prawns were separately tested for the effect of ablation and sex on survival, daily weight gain, final weight, size increment per molt, molt interval and egg production. Survival of jumpers and laggards was about 95%. Eyestalk ablation had no effect on growth of male jumpers. Ablation had a highly significant effect on growth of male and female laggards, manifested in both increase in size increment per molt and shortening of the molt interval. The differential response of jumpers and laggards to eyestalk ablation is indicative of a different socially-determined growth related physiology. Some of the unexplained variability in growth and in rate of related energy metabolism of juvenile prawns (and other crustaceans with a wide size variation) could be due to their relative rank within their original populations.

Effects of Unilateral Eyestalk Ablation on Oxygen Consumption and Ammonia Excretion of Juvenile Penaeus japonicus Bate at Different Salinity Levels

Effects of Unilateral Eyestalk Ablation on Oxygen Consumption and Ammonia Excretion of Juvenile Penaeus japonicus Bate at Different Salinity Levels

Effects of Unilateral Eyestalk Ablation on Growth in Juvenile Blue Crabs Portunus pelagicus(L.) (Crustacea: Decapoda: Portunidae)

The effects of unilateral eyestalk ablation on growth in Portunus pelagicus were investigated using the physiological energy budget method and checked by means of actual growth performance and body condition indices. Unilateral eyestalk ablation significantly increased absorption efficiency and dry meat yield (% of dry weight) by 12.3% and 332%, respectively. It also accelerated molting by 3.4 days. The physiological mechanisms of growth enhancement are increased absorption efficiency and possi­bly also increased feeding rate and decreased energetic loss to carapace. The increased absorption efficiency, standard ammonia excretion rate, and low O:N ratio in ablated crabs indicate the need to determine optimal lipid and protein levels in the diet. Dry meat yield is suggested as a better gauge than whole wet weight for assessing growth response to eyestalk ablation since the reducing effect of ablation on carapace size tends to mask its weight gain enhancement effect.

Effects of Unilateral Eyestalk Ablation and Feeding Frequencies on Growth, Survival, and Body Compositions of Juvenile Freshwater Prawn Macrobrachium rosenbergii.

A feeding trial was conducted to examine the effects of unilateral eyestalk ablation (UEA) and feeding frequencies on the growth, survival, and chemical compositions of whole body for the juvenile freshwater prawn Macrobrachium rosenbergii (0.1g mean initial wet weight) fed on a carb protein-based diet. The results demonstrated that UEA promotes the growth and the ablated prawns are able to reach commercial size (30g) 40 days earlier than intact ones. Although feeding frequencies did not affect the growth and survival of juvenile prawns significantly, ablated prawns fed twice a day produced the best results. In intact groups, feeding once a day was good enough to sustain optimal growth in the present study. Neither UEA nor feeding frequency affected the con-tents of protein, lipid, or the compositions of lipid class and fatty acid of prawn whole body. Major neutral and polar lipids were triglyceride and phosphatidylcholine, respectively, and high levels of 16:0, 18:1 and 18:2n-6 were found in whole body of both ablated and intact prawns.

Effects of unilateral eyestalk ablation on ovarian histology and oocyte size frequency of wild and pond-reared Penaeus monodon (Fabricius) broodstock

Effects of eyestalk ablation on ovarian maturation of wild and pond-reared Penaeus monodon were determined to compare their reproductive potential. This was done by counting the oocyte size frequency in four regions of the ovary and comparing the percentage of each cell type present at each stage of maturation per group. Sampling of ablated prawns was done during three maturation or spawning periods within the first molt cycle after ablation. It took 5 and 14 days for wild and pondreared prawns, respectively, to show signs of ovarian maturation after ablation. Percentage of proliferating cells, the smallest germinal cells in the prawn ovary, was higher in wild unablated (8.3%) than ablated (2.5–5.0%) groups. Significant differences were observed in all cell types at different stages of maturation. In both unablated and ablated prawns, there was a uniform development of the whole ovary and similar occurrence of atresia at all stages. The presence of bigger oocytes in the ovaries of ablated prawns sampled after spawning provided histological evidence for lower number of eggs per spawn and faster rematuration.

YOLK PROTEIN PRODUCTION IN THE MARINE SHRIMP PENAEUS VANNAMEI

ABSTRACT Yolk production of the marine shrimp Penaeus vannamei was measured using an antibody to a subunit of the yolk protein complex. The effects of unilateral eyestalk ablation on protein synthesis of the hepatopancreas and ovary were measured in vitro. Initially, activity in both tissues increased; 21 days after eyestalk ablatior activity levels in both tissues returned to levels equal to or lower than preablation levels. The yolk protein content of the tissues increased shortly after eyestalk ablation and reached a maximum of 8% in ovarian tissue, but less than 1% in the hepatopancreas. Yolk proteins in the hemolymph were detected using an enzymelinked immunoassay. Both intact controls and eyestalk-ablated shrimp had as much as 1 mg/ ml yolk protein in the hemolymph during ovarian maturation. Newly released shrimp eggs had an average of 53 ng yolk protein per egg. Eyestalk ablation induced a rapid increase in protein synthesis in both ovary and hepatopancreas. During ovarian maturation, yolk proteins were transported through the hemolymph in this marine shrimp.

Effects of Unilateral Eyestalk Ablation on Moulting, Growth, Reproduction and Energy Budget of Macrobrachium nobilii

Unilateral eyestalk ablation in juvenile Macrobrachium nobilii advanced the onset of sexual maturity by 88 days. During a 330.day experiment, ablated prawns undertook nine moults as adults, carried seven clutches and produced an average of 6,935 eggs. Nonablated prawns undertook four moults as adults, carried three clutches and produced only 2,042 eggs. Ablated female prawns allocated more energy for egg production than did nonablated females (0.98 J egg-1 and 0.72 J egg-1, respectively); this was accomplished by an improvement of food conversion efficiency in ablated females.