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Gonad Maturation (gonad + maturation)
Selected AbstractsAlternate oils in fish feedsEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 3 2007Jana Pickova Abstract Nearly half of the fish consumed as food worldwide are raised on fish farms rather than caught in the wild, as shown by FAO statistics. The increasing aquaculture of predatory carnivorous fish demands new sources of feed constituents, particularly oils at the moment. Common terrestrial plant oils contain only traces of the long-chain polyunsaturated fatty acids. In connection with fish feed, especially the lack of n -3 "marine fatty acids" is obvious. Recommendations on the required amounts of the fatty acids DHA (22:6n -3) and EPA (20:5n -3) exist from 1994. When plant oil-based diets are fed during the growing phase and replaced by a fish oil-based diet during a period prior to slaughter, most of the beneficial lipid composition of fish in terms of human dietary recommendations is restored. Little attention has been focused on the fish welfare in connection to substitution of dietary oil sources, and studies are still scarce. New fish diets will rely heavily on the use of alternate ingredients such as plant oils also for carnivorous cold-temperate water fish species. In the future, an addition of synthetic or GMO-produced "marine" fatty acids is a possible scenario. The aim of this review is to highlight some plant oils used in fish feeds, with special emphasis on compounds other than fatty acids. We also include some results from an ongoing study, where the effect of dietary soy oil on gonad maturation in Atlantic cod (Gadus morhua) is indicated. [source] Reproductive features of the non-native Siganus luridus (Teleostei, Siganidae) during early colonization at Linosa Island (Sicily Strait, Mediterranean Sea)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2007E. Azzurro Summary In July 2003, the finding of a newly settled population of Siganus luridus at Linosa Island (Sicily Strait, Mediterranean Sea) gave us the unusual opportunity to examine the reproductive condition of a Lessepsian migrant during early phases of colonization. Aspects of gonad morphology, fecundity, atresia and oocyte dynamics were investigated by using 43 pioneer specimens collected in concomitance with their first record in the Pelagie Islands. Ovarian development was consistent with the group-synchronous type, and testicular organization was of the unrestricted spermatogonial testis type, with cystic spermatogenesis. Both males and females had reached final stages of gonad maturation. The rates of follicular atresia were moderate: out of 17 adult females, 10 individuals did not present atretic oocytes; six exhibited <15.1% of secondary growth phase (SGP) oocytes in , -atresia, while one female presented 45.7% of SGP in , -atresia. Fecundity estimates did not diverge from what was observed in a reference population along the Lebanese coast. Absolute fecundity ranged from 115 739 to 740 433 oocytes per female (16.5,24.5 cm LT). Relative fecundity ranged from 1239 to 3162 oocytes g,1, with a mean of 1885 ± 868 oocytes g,1. Our observations indicated that these early settled siganids are reproductively active at Linosa and suggested the forthcoming of self-maintaining populations across the central Mediterranean area. [source] Effect of prepared diet and vitamins A, E and C supplementation on the reproductive performance of cage-reared bighead carp Aristichthys nobilis (Richardson)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2000By C. B. Santiago Twenty-month-old bighead carp, Aristichthys nobilis (Richardson), were fed prepared dry diets for 20 months in cages in Laguna de Bay, Philippines, to determine the effect on reproductive performance. The experimental diets were similar in composition except for the combinations of vitamins being tested. Diet 1 was supplemented with vitamins A, E and C; diets 2, 3 and 4 each lacked one of the supplementary vitamins; and diet 5 did not include any vitamin supplementation. Bighead carp that relied solely on natural food without a prepared diet served as a control. The total of six treatments each had two replicates. Results showed that the onset of gonad maturation was 2,3 months earlier in the fish that were fed the prepared diets regardless of vitamin supplementation, when compared with the fish that were fed natural food (control). Moreover, the prepared diets enhanced egg hatchability which was significantly higher in fish that were fed diet 1 (+ vitamins A, E and C, 80.5 ± 18.1%) and diet 3 (, vitamin E, 78.5 ± 1.1%) than in those fish that were fed natural food (control) (36.5 ± 31.3%). Mean number of 3-day-old larvae was highest in fish fed on diet 1 (34 525 ± 1732), followed closely by fish that were fed diet 3 (32 420 ± 3909). A low number of 3-day-old larvae was obtained from fish fed the natural diet (14 490 ± 4331) as well as in fish that were fed diet 2 (, vitamin A, 14 347 ± 4863), diet 4 (, vitamin C, 21 407 ± 5840) and diet 5 (, vitamin A, E and C, 12 191 ± 1439). Other criteria for reproduction such as relative fecundity, fertilization rate, and hatching rate did not differ significantly (P >,0.05) among treatments. The addition of vitamins also had no significant effects on weight gain of adult fish. [source] Posthatching development of Alligator mississippiensis ovary and testisJOURNAL OF MORPHOLOGY, Issue 5 2010Brandon C. Moore Abstract We investigated ovary and testis development of Alligator mississippiensis during the first 5 months posthatch. To better describe follicle assembly and seminiferous cord development, we used histochemical techniques to detect carbohydrate-rich extracellular matrix components in 1-week, 1-month, 3-month, and 5-month-old gonads. We found profound morphological changes in both ovary and testis. During this time, oogenesis progressed up to diplotene arrest and meiotic germ cells increasingly interacted with follicular cells. Concomitant with follicles becoming invested with full complements of granulosa cells, a periodic acid Schiff's (PAS)-positive basement membrane formed. As follicles enlarged and thecal layers were observed, basement membranes and thecal compartments gained periodic acid-methionine silver (PAMS)-reactive fibers. The ovarian medulla increased first PAS- and then PAMS reactivity as it fragmented into wide lacunae lined with low cuboidal to squamous epithelia. During this same period, testicular germ cells found along the tubule margins were observed progressing from spermatogonia to round spermatids located within the center of tubules. Accompanying this meiotic development, interstitial Leydig cell clusters become more visible and testicular capsules thickened. During the observed testis development, the thickening tunica albuginea and widening interstitial tissues showed increasing PAS- and PAMS reactivity. We observed putative intersex structures in both ovary and testis. On the coelomic aspect of testes were cell clusters with germ cell morphology and at the posterior end of ovaries, we observed "medullary rests" resembling immature testis cords. We hypothesize laboratory conditions accelerated gonad maturation due to optimum conditions, including nutrients and temperature. Laboratory alligators grew more rapidly and with increased body conditions compared with previous measured, field-caught animals. Additionally, we predict the morphological maturation observed in these gonads is concomitant with increased endocrine activities. J. Morphol. 2010. © 2009 Wiley-Liss, Inc. [source] The growth and gonadal maturation of the African catfish, Clarias gariepinus (Burchell) broodstock fed differently heated soybean-based dietsAQUACULTURE NUTRITION, Issue 4 2006A.A. ADEWUMI Abstract An investigation was carried out to assess the growth and gonadal maturation of Clarias gariepinus (Burchell) fed differently heated soybean diets in concrete tanks. Four hundred and eighty male and female C. gariepinus (182 ± 10 g for females and 208 ± 5 g for males) were randomly distributed in groups into hapa nets. Iso-nitrogenous (310 g kg,1 crude protein) and iso-caloric diets (355 Kcal kg,1) prepared from raw soybean (D0) and soybean autoclaved for 5, 10, 15, 20, 25 and 30 min labelled D0, D5, D10, D15, D20, D25 and D30, were fed to the fish for 84 days. The fish meal based diet tagged DFM served as control. The male and female broodfish fed the fish-meal-based diet and diet D25 had significantly higher (P < 0.05) growth performance, gonad maturation, gonadosomatic index, relative fecundity and percentage egg fertilization and hatchability than the fish fed the other diets. The females had significantly higher (P < 0.05) weight increases and healthier condition over their male counterparts fed the same diets. This study showed that diet D25 was found to be the best substitute for fish meal that provided adequate nutrients required for the formation of genital products that produced strong offspring in C. gariepinus broodstock culture. [source] Effects of transplants and extracts of thoracic nerve cord,ganglia on gonad maturation of penaeoid shrimpAQUACULTURE RESEARCH, Issue 2 2010Jorge Alfaro Abstract It has been established recently that interspecific and intraspecific thoracic ganglia transplants from Penaeidae are gradually absorbed by the host without activating an encapsulation mechanism. Therefore, this research was designed to evaluate the thoracic ganglia extracts and implants from maturing Trachypenaeus byrdi (Burkenroad), Xiphopenaeus riveti (Bouvier) and Penaeus (Litopenaeus) occidentalis (Streets) females as potential inducers of sexual maturation in Penaeus (Litopenaeus) stylirostris (Stimpson), Penaeus (Litopenaeus) vannamei (Boone) and T. byrdi, from the Gulf of Nicoya, Costa Rica. Our findings suggest that interspecific and intraspecific thoracic ganglia extracts or implants from maturing penaeoid females are not capable of inducing a clear response in sexual maturation in males or females. Tissues were tested at increasing doses from 137, 386, 525 and 1500 ,g g,1 body weight, without any positive response. It is proposed that a hypothetical hormone, vitellogenesis-stimulating hormone, from the thoracic ganglia, is under the strong negative control of eyestalks, by the gonad-inhibiting hormone in the subgenus Litopenaeus. Therefore, the use of thoracic ganglia extracts or implants would be ineffective when compared with injecting serotonin alone, as the present results seem to support. [source] Quantification of vitellin/vitellogenin-like proteins in the oyster Crassostrea corteziensis (Hertlein 1951) as a tool to predict the degree of gonad maturityAQUACULTURE RESEARCH, Issue 6 2009Fabiola G. Arcos Abstract The oyster's reproductive process is poorly documented, especially in terms of a quantitative approach. In recent years, investigations with this species have been directed at determining important reproductive factors. Within this scope, techniques that allow standardized and accurate quantitative estimations of gonad development have become of primary importance. In this study, the histological characteristics and the levels of vitellin/vitellogenin-like proteins (Vn/Vtg) from ovaries of the Mexican Pacific ,pleasure' oyster Crassostrea corteziensis (Hertlein 1951) were analysed during different stages of gonad maturation using quantitative histological techniques and an enzyme-linked immunosorbent assay. This was performed in order to evaluate a possible quantitative tool to predict the degrees of gonad maturity and to analyse the biological implications of the findings relative not only to broodstock conditioning but also to natural populations. Using this information, we expect to be able to undertake further research on different reproductive aspects of this oyster species, including, among others, evaluation of the response in Vn/Vtg concentrations to different diets and environmental conditions during laboratory conditioning. [source] Comparison of continuous and batch feeding systems on maturation, biochemical composition and immune variables of the oyster Crassostrea corteziensis (Hertlein 1951)AQUACULTURE RESEARCH, Issue 4 2009Miguel A Hurtado Abstract Two feeding systems for maturing oysters were compared, one a continuous feeding system and the other a batch system in which the whole microalgal ration was supplied once daily. The maturation diet consisted in Isochrysis galbana (T-ISO) complemented with an enriched lipid emulsion. Survival and growth did not differ between the feeding systems after 3 weeks of conditioning. Maturation, biochemical composition, fatty acids in membranes and reserves, digestive enzymes activities and immune parameters in Crassostrea corteziensis were analysed. Only oysters fed using the once-daily system had vitellogenic oocytes, whereas the gonad of oysters fed using a continuous-drip system remained immature. Total and differential haemocyte counts were similar between both the systems, but respiratory burst was significantly higher in oysters fed using the once-daily system. Amylase, lipase and trypsin activities in oyster's digestive gland were similar between both the feeding systems. Total lipids, however, differed significantly in oyster tissue in relation to feeding system, with highest level in those fed using the once-daily system, but fatty acid composition in reserves and membrane were similar. No differences were found for biochemical parameters in haemolymph. These results suggest that feeding oysters using a batch, once-daily system allows more rapid initial gonad maturation without affecting general physiological condition and growth. [source] | |||||||||||||