Reproductive performance of gilthead seabream (Sparus aurata L., 1758) fed two combined levels of carotenoids from paprika oleoresin and essential fatty acids

Despite carotenoids and essential fatty acids seem to play important roles in fish reproduction, no studies have yet been conducted to determine the effect of dietary carotenoids on gilthead seabream broodstock performance and their relation as antioxidants with dietary n‐3 highly unsaturated fatty acid (HUFA) levels. In addition, the high cost of synthetic sources of carotenoids is leading to the search for new natural carotenoid sources such as paprika oleoresin. Four experimental diets containing two combined levels of carotenoids from paprika oleoresin (40 and 60 mg kg^?1) and n‐3 HUFA (25 and 40 g kg^?1) were respectively fed to triplicate groups of gilthead seabream (Sparus aurata) broodfish. Elevation of n‐3 HUFA dietary levels from 25 to 40 g kg^?1 significantly improved gilthead seabream broodstock performance in terms of egg viability, hatching rates and fecundity. Besides, it markedly increased egg contents in HUFAs which play important energetic and structural roles and improve embryo development. Both arachidonic acid and eicosapentaenoic acid (20:5n‐3) egg contents were more readily affected by dietary n‐3 HUFA than docosahexaenoic acid. HUFA levels did not caused any negative effect suggesting an optimized content of antioxidants in broodstock diets. Increase in dietary carotenoids from 40 to 60 mg kg^?1 increased carotenoid contents in eggs and significantly improved egg fertilization rates suggesting an important sperm cell’s protective role by reducing the risk of lipid peroxidation which is detrimental for sperm motility. The increased inclusion of dietary paprika oleoresin enhanced egg carotenoid deposition and improved fish reproductive performance, denoting the high nutritional value of this product as a source of carotenoids for broodstock of this species.     

Ultrasound evaluation of the gonadal structure in sex-reversed rainbow trout females

Ultrasound approach has been used to assess morphology of the gonadal structure in the sex-reversed rainbow trout females (neomales) provided in the course of 11β-hydroxyandrostenedione treatment applied within gonadal differentiation period. Eighteen matured individuals (in range 38.0–48.6 cm of body length and 802–1644 g of body weight) were scanned using digital ultrasound apparatus (DP-6900 model) Mindray Ltd., during the spawning season. After screening, fishes were killed to validate the morphological configuration and position of the gonads in the body cavity. The favorable place for cross-sectional imaging of gonadal lobes was half of the distance between the pectoral and pelvic fins below lateral line of neomales. Most of the examined specimens (61 %) had properly shaped, paired testis. Moreover, presence of individuals with asymmetrical gonads (33 %) and one bisexual fish was confirmed. There were no differences between total volume of sampled semen and sperm motility, but statistically significantly different in sperm concentration within selected (with symmetrical and asymmetrical testis) groups of neomales. It was confirmed that ultrasonic imaging is an efficient and accurate method to determine the state of gonads of mature sex-reversed rainbow trout females during spawning season and offers the opportunity for non-invasive detection of any morphological anomalies in their gonads.     

The existence of extra-retinal and extra-pineal photoreceptive organ regulating gonadal development of ayu, Plecoglossus altivelis

The photoreceptors regulating photoperiodic gonadal development of ayu, Plecoglossus altivelis, are not known. In this study, we examined whether the gonads of ophthalmectomized and pinealectomized (Ex+Px) ayu respond to short photoperiod. Gonadosomatic index (GSI) and plasma levels of sex steroids were significantly increased in Ex+Px ayu kept under short photoperiod in both males and females. On the other hand, there were no significant increase in GSI and sex steroids in Ex+Px ayu kept under long photoperiod. The histological observation of the gonads revealed that oocytes undergoing final maturation in females and proliferation of germ cells in males were observed only in Ex+Px ayu kept under short photoperiod. Altogether, our results strongly suggest unknown photoreceptive organ regulates photoperiodic gonadal development of ayu.     

Quantification of eggs and sperm in the Black-lip pearl oyster Pinctada margaritifera using an enzyme-linked immunosorbent assay (ELISA)

We have developed immunological probes to quantify eggs and sperm of the Black-lip pearl (BLP) oyster Pinctada margaritifera. The western blot assay revealed that the polyclonal antibodies developed in this study specifically recognized only egg and sperm proteins. These polyclonal antibodies also showed high sensitivities to the antigens, detecting 0.31–10 μg/ml of the egg or sperm proteins in an indirect enzyme-linked immunosorbent assay (ELISA). Accordingly, we used an indirect ELISA to quantify the eggs and sperm in BLP oysters collected in December 2009 from Weno Island in Micronesia and in May 2010 from Tahiti. The gonad somatic index (GSI), a ratio of gonad weight to somatic tissue weight, of the females collected from Weno Island ranged from 3.6 to 18.4 %, while the GSI of the females collected from Tahiti ranged from 5.6 to 12.6 %. Similarly, the GSI of the male BLP oysters from Weno Island ranged from 0.8 to 8.5 %, while the GSI of the males from Tahiti ranged from 4.8 to 7.5 %. These results lead to the conclusion that the immunological probes developed in this study can be successfully applied to quantify BLP oyster gonadal tissues and that these probes can be used in studies of BLP oyster reproductive ecology based on their sensitivity, rapidity, and affordability.     

The Effect of Dietary Carotenoids on Gonad Production and Carotenoid Profiles in the Sea Urchin Lytechinus variegatus

Although dietary carotenoids are generally considered important in sea urchin aquaculture only for their effect on gonad color, they also have important biological roles. The effects of dietary carotenoids on gonad production and organ carotenoid profiles of Lytechinus variegatus were examined. Individuals were collected in January 1999 and fed a replete diet with a level of 0.60 mg carotenoids/kg for 4 wk, followed by one of four prepared diets for 8 wk: one without supplemental carotenoids, one with β‐carotene (16.92 mg carotenoids/kg feed), and two carotenoid mixtures, one high in zeaxanthin (5.28 mg carotenoids/kg feed) and another high in capsanthin (9.63 mg carotenoids/kg feed). The carotenoid profiles of the body compartments differed. The primary carotenoid in gonads of males and females was echi‐nenone. The carotenoid profile of the test was similar to that of the gonad. The carotenoid profile of the gut varied with diet, but was not identical to composition of the diet. The gut profiles included echinenone but at lower concentrations than in the gonad and test. The carotenoid profile in the gut probably results from the presence of the carotenoids absorbed and those metabolized. The results suggest that several pathways exist to metabolize dietary carotenoids and that some of them are in the gut. The concentration of carotenoids in the gut (g wet weight) was higher than that of the gonad, which was higher than that of the test. The gonads increased significantly in size regardless of diet, indicating carotenoids are not required for gonad production under the conditions of this experiment. Although the concentration of carotenoids in the gonad decreased over time, the absolute amount of carotenoids increased with the increase in gonad size. Either gonad growth was more rapid than carotenoid deposition or differential deposition in nutritive cells and gametogenic cells occurred, or the amount of carotenoids used in the diets was too low to have an effect.     

Effects of dietary carotenoid on the gut and the gonad of the sea urchin Paracentrotus lividus

Gonad colour, determined by accumulated carotenoids, is an important marketability factor in sea urchin products. In this study, dietary carotenoids were fed to Paracentrotus lividus in prepared diets to test their effects on the sea urchin's gonad colour. All diets had the same basic content of protein, lipid, carbohydrate, ash and energy. Four diets were enriched with: (I) all-trans β-carotene; (II) astaxanthin; (III) zeaxanthin/lutein/β-carotene; and (IV) capsanthin/zeaxanthin/lutein/cryptoxanthin/β-carotene. A fifth diet had Dunaliella bardawil algal powder containing all-trans and 9-cis β-carotene added, and a sixth one was a control diet with no added carotenoids. Sea urchins were fed the control diet (no pigments) for 4 weeks, then the six experimental diets for 8 weeks. Carotenoid concentration in the gut and gonad was determined by tri-dimensional photo-diode array high performance liquid chromatography. Four qualitative colour categories were established: brown, pale yellow, medium-orange, and mango-orange.Gonad development and test diameter increased equally in all diet treatments. Carotenoid profile and concentration in the gut were higher than in the gonad or in the feed. Total carotenoid concentration was four- to ten-fold greater in the gut than in the gonad, and carotenoid profile in the gut was different from that of the diet. Gut and gonad total carotenoids, β-carotene, and echinenone concentration were not dependent on total dietary carotenoid concentration. Total carotenoid and β-carotene concentration in the gut, and total carotenoid and echinenone concentration in the gonad were significantly dependent on dietary β-carotene concentration. The percentage of gonads with acceptable colour was positively correlated with dietary and gut β-carotene concentration. Carotenoids not normally contained in the diet of P. lividus (astaxanthin, capsanthin and capsorbin), did not accumulate in the gonad. Echinenone was found in all gut and gonad samples. Over 90% of the gonads from P. lividus fed Dunaliella algal powder diet developed the optimal mango-orange colour and this diet led to the greatest echinenone concentration.     

Influence of broodstock diet on somatic growth,fecundity, gonad carotenoids and larval survival of sea urchin

The effects of formulated feeds on Paracentrotus lividus broodstock performances and carotenoid compositions were investigated. Performance of offspring derived from each dietary treatment was compared to determine whether maternal provisioning of nutrients affected offspring development and survival under commercial culture conditions. At the end of the experimental period (3 months), urchins were induced to spawn, relative fecundity measured, and offspring derived from each treatment were reared independently and survival up to competence assessed. Carotenoid composition of the gonads was also measured. Data showed that the highest dietary protein content significantly improved somatic growth, whereas higher lipid content increased gonadal index (GI) consistent with the use of gonads as nutrient storage in sea urchins. Nonetheless, gonad lipid concentration was not significantly different between treatments indicating that higher dietary lipid content favoured gonadal size rather than increase lipid content of the gonadal tissue. Interestingly, GI and fecundity were not correlated, although the latter may have been enhanced by dietary xanthophyll. This suggests the importance of including carotenoids in broodstock diets to enhance hatchery outputs. This study also indicated that, although broodstock diet can influence fecundity, it had no significant impact on larval survival, which could instead be influenced by rearing conditions.     

饲料中添加南极磷虾粉对凡纳滨对虾亲虾生长、性腺发育及脂肪酸积累的影响

为探讨人工配合饲料中添加磷虾粉对凡纳滨对虾(Litopenaeus vannamei)亲虾性腺发育的影响,分别在饲料中添加0、10%、20%的南极磷虾粉,配制3组人工配合饲料(饲料组1、饲料组2和饲料组3)对12月龄的凡纳滨对虾进行了为期60 d的营养强化培养,并以投喂双齿围沙蚕(Perinereis aibuhitensis)为对照组。营养强化结束之后,比较分析了不同饲料组凡纳滨对虾亲虾的体重增重率、肝胰腺指数(HPI)和性腺指数(GSI);另外,检测分析了各组饲料以及亲虾性腺和肝胰腺的脂肪酸组成。结果表明,对照组的雌雄亲虾体重增重率均高于3个饲料组;饲料组2的HPI最低,为(2.37±0.02)%,与对照组无显著差异(P0.05);饲料组3的GSI与对照组无显著差异(P0.05),但两组的GSI均低于饲料组2,并且存在显著差异(P0.05)。同时,本研究还比较分析了饲料脂肪酸组成与亲虾性腺、肝胰腺脂肪酸组成的相关性以及对亲虾性腺发育的影响。结果显示,饲料中添加一定含量(10%~20%)的南极磷虾粉可在一定程度上成为凡纳滨对虾亲虾营养强化阶段的优良饲料。     

Aspects of the reproductive biology of the sharpsnout seabream Diplodus puntazzo (Cetti, 1777). I. Gametogenesis and gonadal cycle in captivity during the third year of life

A histological study was made of the reproductive cycle of captive sharpsnout seabream Diplodus puntazzo during the 3rd year of life. All specimens contained both ovarian and testicular tissue. Ovarian tissue prevailed in 64 out of 120 fish sampled throughout one year. The ovary underwent a long resting phase from October to August, during which time it contained oogonia, primary growth phase (PGP) and occasional yolk vesicle stage oocytes. Intense ovarian development took place in September leading to the formation of advanced vitellogenic oocytes. Final maturation and spawning were not achieved in any of the fish. The testicular area in the predominantly female gonads contained only spermatogonia and was found to be histologically normal in 76% of individuals, but severely regressed in the remaining fish. The testicular portion was found to be dominant in 56 out of 120 fish sampled throughout one year. These underwent a resting phase from November to July, a maturing/pre-spawning phase in August, and a spawning phase with spontaneous sperm release in September to October, as in the natural environment. The ovarian portion in the functional male gonads contained only oogonia and oocytes which did not develop beyond the perinucleolus stage at any point during the reproductive cycle. Apart from the pre-spawning/spawning phase, during which the gonadosomatic index (GSI) was comparable in the two groups, the GSI values were approximately ten-fold higher in those fish in which the ovary predominated than in those in which the testis predominated.     

Influence of gonadal development on metal accumulation in the Portuguese oyster,Crassostrea angulata,in subtropical areas

Metal enrichment makes oyster considered to be an appropriate food source for trace elements, but excessive accumulation can threaten human health. Reproduction is an important biotic factor that affects the metal accumulation in oysters. However, the influence of continuous gonad development model on metal accumulation in some subtropical oysters is still unclear. The present study addresses the concentrations of trace metals and glycogen associated with the gonadal and somatic tissues throughout the reproductive cycle of diploid and triploid Crassostrea angulata cultured in Fujian, China. Cu, Zn and Pb contents of gonads were negatively correlated (p < 0.05) with gonadosomatic index (GSI). The correlation between Cd content and GSI was not significant. There was a positive correlation (p < 0.05) between GSI and Mn content in female gonads while the correlation was negative (p < 0.05) in males, indicating Mn plays an important role in gametogenesis of females. The effects of gonadal maturity and gender on metal accumulation in somatic tissue were not significant (p > 0.05). The concentrations of all metals in sterile triploids were not significantly different from those of the somatic tissue of diploids. Gonadal glycogen content showed a negative correlation with the GSI. However, somatic glycogen content was not affected by gonadal development, indicating that the energy consumed during gametogenesis comes mainly from recently ingested food rather than from energy stored in somatic tissue. The effects of the gonadal development on the metal accumulation in oysters varied according to the metal and tissue type.     

Pigmentation of cultured red sea bream, Chrysophrys major, using astaxanthin from Antarctic krill, Euphausia superba, and a mysid, Neomysis sp.

Pigmentation enhancement in cultured red sea bream, Chrysophrys major, was investigated using Antarctic krill, Euphausia superba, and a mysid, Neomysis sp., as a source of astaxanthin. Diets fortified with processed Antarctic krill (krill meal) and its acetone extract, containing 0.82–4.92 mg carotenoids/100 g dry weight, and raw krill and raw mysid supplemented diets, containing about 2.00 mg carotenoids/100 g wet weight, were formulated and tested for carotenoid deposition. The rate of carotenoid deposition in fish fed with raw krill and raw mysid was significantly higher and resulted in distinct pigmentation. The groups fed with the krill meal and acetone extract diets showed varied concentrations of skin carotenoids and resulted in faint pigmentation. Pigmented fish then fed on a carotenoid-free diet for the same length of time showed no apparent differences in the skin pigmentation although the detectable amounts of carotenoids varied. The bream converted some of the dietary astaxanthin to skin tunaxanthin.     

中华鳖SOX9基因在胚胎期性腺中的表达模式及在性逆转中的表达变化

SOX9基因在脊椎动物性别决定和性腺分化中扮演重要的调控作用。从mRNA和蛋白水平分析中华鳖SOX9基因在不同组织中的差异性表达、在胚胎性腺和成年睾丸中的细胞定位以及在性逆转中的表达变化,研究SOX9基因在中华鳖性别分化中的调控作用。Real-time PCR结果显示,SOX9基因在中华鳖雄性性腺中特异性表达。免疫荧光染色分析显示,SOX9蛋白在雄性18期胚胎性腺中开始表达,随着性腺的发育,SOX9蛋白定位于性腺Sertoli前体细胞细胞核中;而在雌性胚胎性腺并未见其表达。此外,在雌激素诱导的雄性向雌性性逆转胚胎中,SOX9基因显著下调,而在芳香化酶抑制剂诱导的雌性向雄性性逆转胚胎中,SOX9基因表达则显著上升。研究表明,SOX9基因为中华鳖雄性特异性基因,参与雄性性腺的发育过程,可能在中华鳖早期性别分化过程中起调控作用。     

Effects of Season,Strain, and Body Weight on Testes Development and Quality in Three Strains of Blue Catfish,Ictalurus furcatus

Production of channel catfish, Ictalurus punctatus, female × blue catfish, Ictalurus furcatus, male hybrids has increased dramatically in the USA. Hybrid production requires surgical removal and maceration of blue catfish testes. Farmers report individual and seasonal variation in blue catfish testes development, and understanding the factors influencing testes development could improve hybrid catfish production. Effects of season (mid‐May vs. mid‐June), strain (D&B, Missouri, and Texas), and body weight on testes development in 5‐yr‐old blue catfish were determined. Males were measured in mid‐May and mid‐June for length, body weight, testes weight, and gonadosomatic index (GSI). Total sperm/g of testes, percent motility, and motile sperm/g of testes were determined. D&B strain males weighed more and had larger testes with more sperm than Missouri or Texas strain males in both months. Mature Texas strain males were larger than immature Texas strain males in both months. Testes were larger and had more sperm in May than in June for all strains; however, there were males from each strain with good quality testes in June. GSI, sperm/g of testes, percent motility, and motile sperm/g of testes were positively correlated. Information from this study provides a better understanding of factors influencing testes development in blue catfish.     

Quantitative measurement of reproductive output in the American oyster, Crassostrea virginica (Gmelin), using an enzyme-linked immunosorbent assay (ELISA)

Abstract. A quantitative gonadal index was developed for oysters, Crassostrea virginica (Gmelin. 1791), using polyclonal antibodies from eggs and sperm. Percoll used in the purification of oyster eggs and sperm greatly improved the purity of antigens compared to filtering the egg or sperm through a fine mesh only. The antigen-antibody reaction was tested with indirect sandwich ELISA using alkaline phosphatase-conjugated goat anti-rabbit igG as a secondary antibody. Rabbit anti-oyster egg IgG and anti-oyster sperm IgG initially exhibited a weak cross-reactivity over somatic tissue. Absoring with acetone-dried oyster tissue powder removed this cross-reactivity. Both antisera exhibited strong specific immunological reactions to oyster eggs or sperm respectively. The quantity of eggs or sperm was measured using ELISA and a quantitative gonadosomatic index (dry wt of egg or sperm/dry wt oyster) (GSI) calculated. GSI from ELISA correlated with gonadal stage measured histologically. Monthly mean GSI of female oysters was highest during late spring to early summer (0·157–0·201) and lowest during early winter to early spring (0·002-0·000). Maximum GSI observed during the study was 0·422 for female oysters and 0·446 for male oysters. Female oysters produce 3·7–65·4 million eggs, with an average of 21·1 million during each spawning. A positive correlation was observed between the number of eggs produced and oyster size; the number of eggs in the gonad increased as oyster size (i.e. total dry wt) increased (r= 0·67); however, the relationship was non-linear. Large oysters contained proportionally fewer eggs. Prevalence of Perkinsus marinus parasitism was high, 90–100%, during the study, as was weighted incidence, 1·33 to 2·67, No statistically significant correlation was observed between infection intensity and the per cent weight of oyster eggs or egg number.     

Sperm from pheromone primed brown trout (Salmo trutta L.) produce more larvae

Male goldfish (Carassius auratus) exposed to female hormonal pheromones express increased milt volumes and their sperm fertilize more eggs than sperm from unprimed males. Ovulated salmonid females also release odours that increase volumes of strippable milt in males. It is, however, not known if the priming pheromones affect the ability of sperm to fertilize eggs in salmonids. In this study, we compare the proportion of larvae produced from in vitro fertilization tests between primed brown trout (Salmo trutta) males exposed to a mix of female urine and ovarian fluids, and control males exposed only to 0.9 % sodium chloride. We also investigate priming effects on milt yield and sperm motility. Fertilization tests with sperm from single males, as well as sperm from two males (i.e., sperm competition), were performed. Primed males generated more larvae in both the single male and competition fertilization tests. No differences between treatments in milt yield and sperm motility could be established.     

Influence of the Reproductive Cycle of Argentinian Hake (Merluccius hubbsi) on Fillet Yield and Operating Costs

Seasonal variations in gonadosomatic index (GSI), in the liver-somatic index (LSI), and in fillet yield of mature hake (Merluccius hubbsi) were investigated. A resting or slow recuperation period and another one of rapid transformation (October-February) were observed in gonads of female hakes. The latter occurred earlier in male fish than in female ones. Spawning took place in March. High LSI values were found after spawning and during the gonadal resting period. Low LSI values together with high GSI values were observed. For the hake filleting operation, yield of weight profile was very similar to that of LSI. A linear correlation was obtained when LSI values were plotted against fillet yield (r² = 0.818, P < 0.001). The unit cost, as well as the yield, can be linearly correlated with the LSI. This equation allows estimation of the production cost when raw material of equal initial quality in different seasons of the year is processed. The results presented are useful for inventory policies in fish plants.     

Carotenoid deposition in pen-reared salmonids fed diets containing oil extracts of red crab (Pleuroncodes planipes)

The rate of deposition of carotenoids in pen-reared coho salmon was investigated by the addition of known carotenoid levels to diets. The carotenoids added to the diets were derived from red crab (P. planipes), and a process is described for the preparation of a soya oil carotenoid concentrate. Using a 3-stage counter-current extraction process, extracts containing 155 mg/100 g oil were prepared from red crab (P. planipes). Oregon moist pellets containing 3, 6, and 9 mg carotenoid/100 g were prepared using these extracts and were fed to coho salmon (Oncorhynchus kisutch) for 120 days. The amount of carotenoid deposited in the flesh of the fish was related to the carotenoid content of the diet and to the weight of the fish. Fish fed diets containing 6 and 9 mg carotenoid/100 g for the same length of time contained 60% more flesh carotenoids than those fed 3 mg/100 g. In general, after 120 days of feeding, only those fish feeding on diets containing 6.0 and 9.0 mg carotenoid/100 g and weighing over 215 g were assessed as having good-to-excellent coloration. Analysis of the flesh showed that there was no correlation between its carotenoid and fat contents.     

Carotenoid pigmentation in relation to feed intake, growth and social interactions in Arctic charr, Salvelinus alpinus (L.), from two anadromous strains

Feed intake, growth and carotenoid pigmentation in 1 + Arctic charr, Salvelinus alpinus (L.), of the Hammerfest and Svalbard strains were studied in fish reared in either separate or mixed groups for 11 weeks.
Hammerfest charr grew faster than charr from the Svalbard strain at the group level. The slower overall growth in the Svalbard strain was accompanied by greater variability in feed intake and growth rates than observed amongst the fish of the Hammerfest strain. The higher incidence of bite marks amongst the Svalbard chart suggested that aggressive encounters were more frequent amongst fish of this strain. No significant differences were observed in muscle carotenoid concentration. There was, however, a highly significant positive correlation between muscle carotenoid concentration and weight gain for individual fish of both strains, irrespective of whether the fish were reared separately or in mixed groups. Estimates of muscle carotenoid retention varied from 78 to 96 mg g⁻¹, but there were no differences between strains or between fish reared in single or mixed-strain groups.
There were no differences in muscle carotenoid composition between strains or between fish reared in separate or mixed groups. Astaxanthin and idoxanthin, a metabolite of astaxanthin, were present in approximately equal proportions, and made up about 99% of the muscle carotenoid content.
The results of this study suggest that flesh pigmentation and its variability may be profoundly influenced by the level of social interactions, mediated through effects on feed intake and growth. These effects may mask genetic variations in the capacity to deposit carotenoids.     

The antioxidant system of seminal fluid during in vitro storage of sterlet <Emphasis Type="Italic">Acipenser ruthenus</Emphasis> sperm

The role of the seminal fluid antioxidant system in protection against damage to spermatozoa during in vitro sperm storage is unclear. This study investigated the effect of in vitro storage of sterlet Acipenser ruthenus spermatozoa together with seminal fluid for 36 h at 4 °C on spermatozoon motility rate and curvilinear velocity, thiobarbituric acid reactive substance level, and components of enzyme and non-enzyme antioxidant system (superoxide dismutase and catalase activity and uric acid concentration) in seminal fluid. Spermatozoon motility parameters after sperm storage were significantly decreased, while the level of thiobarbituric acid reactive substances, activity of superoxide dismutase and catalase, and uric acid concentration did not change. Our findings suggest that the antioxidant system of sterlet seminal fluid is effective in preventing oxidative stress during short-term sperm storage and prompt future investigations of changes in spermatozoon homeostasis and in spermatozoon plasma membrane structure which are other possible reasons of spermatozoon motility deterioration upon sperm storage.     

Effect of the addition of six antioxidants on sperm motility,membrane integrity and mitochondrial function in red seabream (<Emphasis Type="Italic">Pagrus major</Emphasis>) sperm cryopreservation

The present study was to evaluate the effects of six antioxidants on frozen-thawed sperm motility, viability, membrane integrity and mitochondrial function in red seabream (Pagrus major) by computer-assisted sperm analysis system and flow cytometry, respectively. All the parameters tested in this study were determined using one-way ANOVA and identified using the SNK test (P < 0.05). The results demonstrated that on the first day, the highest motility and longevity occurred in 100 mM trehalose (78.34 ± 3.41 %, 29 ± 4.00 days) and 50 mM taurine (77.46 ± 1.54 %, 29.33 ± 4.04 days), followed by 25 mM vitamin C (79.03 ± 5.37 %, 17 ± 1.00 days), 25 mM vitamin E (69.64 ± 1.64 %, 27.67 ± 1.53 days) and 25 mM vitamin A (78.89 ± 2.81 %, 9.33 ± 1.53 days), which were all higher than frozen-thawed sperm without antioxidant (control) (66.80 ± 5.55, 5.67 ± 1.15 days). Especially, the percentages of class A sperm with the addition of 100 mM trehalose (40.39 ± 5.20 %) and 50 mM taurine (37.78 ± 3.22 %) were significantly improved compared to the control (19.63 ± 5.44 %). The viability of all groups on the third and sixth day showed a similar trend. Moreover, during the 4 °C storage process, the decrease of frozen-thawed sperm motility was closely associated with the decrease in membrane integrity and mitochondrial function. In conclusion, the present study indicated that antioxidant (100 mM trehalose and 50 mM taurine) provided the most pronounced protective effect in improving frozen-thawed quality of red seabream sperm. The addition of antioxidant may be capable of scavenging the ROS generated during the cryopreservation process and 4 °C storage.