Volume 59, Issues 1-4, 2007

Masculinization of African Catfish (Clarias gariepinus) Treated with Gokshura (Tribulus terrestris)

Turan, Funda; Cek, Sehriban — Mon, 01 Jan 2007 00:00:00 GMT

The present paper describes the effects of Tribulus terrestris, a masculinization agent, on the sex reversal of African catfish, Clarias gariepinus. One-day-old hatchlings were immersed in water containing an extract of T. terrestris at a rate of 0, 3, 6, or 9 g/30 l water for 30 days. The 9 g treatment resulted in 80.42% male populations. Morphological and histological examinations of the gonads in all groups revealed no intersex fish. Histological examination of fish treated with T. terrestris revealed no damage to the testes or ovaries. Despite differences in sex ratio, growth rate, ovaries, and testes, fish treated with T. terrestris were histologically similar to fish from the control groups. Survival ranged from 72% in the 3 g group to 80% in the 9 g during treatment and did not significantly differ from the control (p>0.05). The best growth was obtained in the 9 g treatment.

Effects of a Probiotic Bacterium, Lactobacillus acidophilus, on the Growth and Survival of Pearl Oyster (Pinctada margaritifera) Spat

Subhash, S.K.; Lipton, A.P. — Mon, 01 Jan 2007 00:00:00 GMT

The present study investigated the effect of a probiotic bacterium, Lactobacillus acidophilus, on the growth and survival of pearl oyster, Pinctada margaritifera, spat. The probiotic bacteria was fed together with a microalgal feed at 1:1 or 2:1 while control groups received no probiotic sup- plementation. The probiotic groups had significantly higher survival (78.7±8.1 and 85.7±2.9%, respectively) than the control groups (60.7±1.2%). Weight and length also increased significant- ly. The weight gains in the probiotic groups were 349.8±0.44 mg (1:1 level) and 396.8±0.49 mg (2:1 level) mg, compared to 300.9±0.51 mg in the control. The increases in dorso-ventral mea- surement were 20.08 mm (1:1 level) and 21.04 mm (2:1 level) in the probiotic groups, compared to 14.22 mm in the control.

Embryonic and Pre-Larval Development of Shabbout (Barbus grypus H.)

Sahinoz, Erdinc; Dogu, Zafer; Aral. Faruk — Mon, 01 Jan 2007 00:00:00 GMT

As a preliminary step towards assessing its aquaculture potential, egg development and artificial breeding in shabbout (Barbus grypus Heckel 1843) was studied. Artificial insemination was achieved by mixing eggs and a sperm-testes extract. The fertilization rate was 60%. Diameters of fertilized eggs ranged 2.58-2.70 mm. The perivitelline space formed 20 min after insemination and contained no oil droplets. A blastodisc split two blastomeres of nearly equal size 80 min after insemination and first cleavage occurred 4-4.5 h after insemination. The gastrula stage was completed after 12.5 h and the embryonic body formed after 14 h. The first somites were observed at 28 h and the first heartbeat at 72 h. The first hatched larva appeared at 84 h and all eggs hatched within 92 h. The mouth opening occurred after 188 h. Head pigmentation was nearly complete together with the formation of the tail fin by 480 h, after which the tail fin gained its homocercal formation and the pigmentation spread throughout the body.

Reproductive Performance of Wild and Hatchery-Reared Black Sea Salmon

Sahin, Temel; Akbulut, Bilal; Cakmak, Eyup; Cavdar, Yahya — Mon, 01 Jan 2007 00:00:00 GMT

Spawning period, total fecundity, egg size, and fertilization and hatching rates of wild and hatch- ery-reared Black Sea salmon (Salmo trutta labrax Pallas, 1811) were investigated. Wild brood- stock consisted of 15 females (4-5 years old) with a mean weight of 1773.2±1014.4 g. Hatchery- reared broodstock consisted of 28 females (3 years old) with a mean weight of 869.5±319.6 g. The spawning period lasted from mid-November to the beginning of January. Mean total fecun- dity was 3524.6±2106.9 and 1931.3±915 eggs/female for wild and hatchery-reared broodstock, respectively, and mean egg diameters were 5.2±0.20 and 5.0±0.24 mm. Fertilization and hatch- ing rates were 98.4±1.71% and 88.1±8.78% for wild broodstock and 97.9±1.84% and 83.1±15.77% for hatchery-reared. The reproductive parameters of wild and hatchery-reared Black Sea salmon in northeastern Turkey were similar to those of other salmonid species.

Color Enhancement in the Ornamental Dwarf Cichlid Microgeophagus ramirezi by Addition of Plant Carotenoids to the Fish Diet

Harpaz, Sheenan; Padowicz, Daniel — Mon, 01 Jan 2007 00:00:00 GMT

The present research examined the effects of adding carotenoids from oleoresin paprika to fish feeds for ornamental dwarf cichlid, Microgeophagus ramirezi. The growth rate, survival, carotenoid accumulation level, and color intensity were evaluated. Post larvae and near-adult (three months old) fish were tested to determine when carotenoids are better assimilated. The addition of carotenoids had no effect on the growth rate or survival in either life stage, however, they had a clear effect on color enhancement. After 45 days, near-adult fish that consumed carotenoid-supplemented diets at 60, 120, or 240 mg/kg had significantly higher levels of carotenoids (72.19±4.55, 84.81±5.29, and 86.55±4.50 μg/g dry matter, respectively) than con- trol fish (33.69±1.06 μg/g), with no significant differences between treatments. After 75 days, post larvae that consumed 240 mg/kg carotenoids accumulated significantly more carotenoids in their body (59.34±3.93 μg/g dry matter) than fish that consumed only 60 mg/kg carotenoids (40.53±2.37 μg/g dry matter) or no supplemental carotenoids (29.18 μg/g dry matter). Visual examination revealed a strong correlation between level of pigment accumulation and color appearance in the fish. Results indicate that addition of 60 mg oleoresin paprika per kg diet is sufficient to obtain good coloration in M. ramirezi.

Effects of 2,2-Dichlorovinyl Dimethyl Phosphate (DDVP) on Hsp70 Gene Expression in Rainbow Trout

Mon, 01 Jan 2007 00:00:00 GMT

2,2-Dichlorovinyl dimethyl phosphate (DDVP) is used to control insects on crops, household, and stored products, and treat external parasitic infections in farmed fish, livestock, and domestic animals. Ectoparasitic copepods can cause severe skin damage in fish that may lead to death through osmoregulatory failure or infection by opportunistic pathogens. There is considerable uncertainty about whether or not DDVP is implicated in cancer, and the wider environmental con- sequences of its use. In general, and specifically in developing countries and fish farming, less hazardous alternatives are available. The present experiment studied the effects of DDVP at a daily dose of 1.6 mg/l for 21 days on the expression of the heat shock protein (Hsp) 70 gene in rainbow trout (Oncorhynchus mykiss). Hsp70 from control and DDVP-exposed fish was ampli- fied for 20-40 PCR cycling. After the fortieth PCR cycle, the Hsp70 level in mRNA was very low in the control fish and very high in the DDVP-exposed fish, with a statistical difference of p<0.01.

Genetic Diversity of Gilthead Seabream (Sparus aurata) Broodstocks as Determined by RAPD-PCR

Bilgen, Guldehen; Akhan, Suleyman; Arabaci, Muhammed; Oguz, Ismall — Mon, 01 Jan 2007 00:00:00 GMT

The objective of this study was to determine the genetic diversity in gilthead seabream brood- stocks from two hatcheries on the northern Aegean Coast of Turkey by RAPD-PCR. Forty primers were tested for each broodstock. Twenty-five produced scorable RAPD bands in stock from the Seferihisar hatchery and 28 in stock from the Aliaga hatchery. Nineteen revealed pat- terns with scorable amplified primers in both broodstocks. Depending on primer, the number of bands varied 3-16, ranging in size from 438 to 2520 base pairs (bp). The average genetic simi- larity within stocks was 0.466 for the Seferihisar stock and 0.617 for the Aliaga. The average genetic similarity between the two broodstocks was 0.420, lower than the values within the broodstocks, and the genetic distance between the two broodstocks was 0.245.

Use of PCR-RFLP Analysis of mtDNA Cytochrome-b Gene to Determine Genetic Differences in Capoeta spp.

Aksakai, Ercument; Erdogan, Orhan — Mon, 01 Jan 2007 00:00:00 GMT

Genetic differences between Capoeta capoeta capoeta, Capoeta capoeta umbla, and Capoeta tinca were determined using PCR-RFLP of mtDNA cytochrome-b (Cyt-b) by amplifying approxi- mately 400-500 bp of this region from each of the three subspecies. The restriction enzymes SpeI and HinfI did not indicate genetic differences but AluI and HpaII did. Thus, PCR-RFLP of the mtDNA was used to distinguish between closely related subspecies without having to ana- lyze the entire DNA sequence of specimens. Use of this technique demonstrated that the Cyt-b regions of the three subspecies have different base sequences. The similarity between C. c. capoeta and C. c. umbla is 71.4% while C. tinca is more distant (50% for C. c. umbla and 33.3% for C. c. capoeta). The Cyt-b similarity is consistent with morphological and taxonomical similar- ities. PCR-RFLP can serve as a tool for genetically identifying subspecies of fish in nature and in aquaculture.

Diet-Influenced Performance of Juvenile Common Carp (Cyprinus carpio L.) after Experimental Aeromonas Infection

Mon, 01 Jan 2007 00:00:00 GMT

The effects of two diets, SGP 493 (Aller Aqua, Denmark; SGP) and chironomid larvae (Katrinex, Poland; CHI), on juvenile carp survival and hematological values after subcutaneous infection with Aeromonas veronii bt. sobria (strain K144) were studied. All infected fish developed skin ulcers and both groups developed anemia, i.e., a severe reduction in hemoglobin content with- out a decrease in red blood cell count and a minor decrease in hematocrit. There were higher levels of hematocrit, hemoglobin, and mean cell hemoglobin in the CHI group at the beginning of the infection, together with a slightly higher erythropoietic potential. At the end of the experi- ment, partial recovery of hemoglobin levels took place. The SGP diet induced considerable leukocytosis in healthy fish, which did not enhance their resistance to the infection. Leukopenia, lymphopenia, and reduced phagocyte activity took place in all infected fish. Survival 15 days after injection was 50% in SGP and 63% in CHI, suggesting that fish fed natural food were slight- ly less susceptible to Aeromonas-induced anemia even though feeding natural food or SGP did not significantly affect the performance of infected fish.

The Fatty Acid Profile of the Marine Cephalopod Loligo vulgaris

Salman, Yesim; Salman, Alp; Ozkizilcik, Sureyya — Mon, 01 Jan 2007 00:00:00 GMT

Squids and their by-products are widely used as pre-spawning feeds in marine fish hatcheries. Therefore, we studied the fatty acid composition of mantle tissue, arms, fins, and gonads of the marine cephalopod, Loligo vulgaris, from a broodstock nutrition point of view. Docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids represented nearly half (>45%) of the total fatty acids, with DHA the most abundant fatty acid in all investigated tissues. The fatty acid profile of the gonads differed significantly from those of the mantle, arms, and fins; EPA was present in a sig- nificantly higher proportion (20%), perhaps indicating its important role in reproduction. Results indicate that Loligo vulgaris and its by-products can be an important nutritional component of broodstock feeds, serving as a major source of DHA and EPA.

Occurrence and Distribution of Actinomycetes in Marine Environs and their Antagonistic Activity against Bacteria that is Pathogenic to Shrimps

Sahu, Maloy zkumar; Murugan, M.; Sivakumar, K.; Thangaradjou, T.; Kannan, L. — Mon, 01 Jan 2007 00:00:00 GMT

The mean population density of actinomycetes in water samples from eight stations off Little Andaman Island in India ranged from 0.29 x 103 CFU/ml at station 2 (Naval Area) to 0.45 x 103 CFU/ml at station 4 (Chandra Nallah). Density in sediment samples ranged from 1.21 x 103 CFU/g at station 2 (Naval area) to 3.29 x 103 CFU/g at station 6 (Buttler Bay). Forty-one strains were isolated and tested for their antagonistic activity against Vibrio alginolytics, V. harveyi, and V. parahaemolyticus, bacteria that are highly pathogenic to shrimps. Over 60% of the strains (26) exhibited varying degrees of antagonistic activity. Among them, six showed good activity and were tentatively identified as Streptomyces xantholiticus, S. aureofasciclus, S. galtieri, S. vastus, S. galbus, and S. rimosus. Results suggest that actinomycetes from the marine environment can be used as bio-control agents in shrimp culture systems to control diseases caused by bacteri- al pathogens.

Pituitary Collection from Gibel Carp Carassius gibelio (Bloch 1782) in Lake Pamvotis (Greece): Prospects for Use in Carp Reproduction

Mon, 01 Jan 2007 00:00:00 GMT

Gibel carp (Carassius gibelio Bloch, 1782) is regarded as a pest species in most aquatic ecosys- tems where it occurs and eradication methods have not been very promising. However, because of the close taxonomical proximity between gibel carp and cultured cyprinids, the pituitary of gibel carps could be exploited for hormonal induction of artificial propagation in aquaculture. Thirty-two mature female gibel carps were electrofished in Lake Pamvotis (northwest Greece) in March 2005 and their pituitaries were collected and processed. The carp luteinizing hormone (cLH) levels in 20 pituitaries were assayed and found to correlate with total body weight, total length, dry pituitary weight, and gonadosomatic index. The cLH levels were in the same range as cLH levels in pituitaries of common carp (Cyprinus carpio Linnaeus, 1758) used in Israeli hatcheries for artificial propagation. Hence, it may be possible to use gibel carp pituitaries for hormonal induction in cyprinids, with total weight of the gibel carp as a field criterion for select- ing pituitary donors.

Immunostimulatory Effects of a Yeast (Saccharomyces cerevisiae) Cell Wall Feed Supplement on Rohu (Labeo rohita), an Indian Major Carp

Pal, Devonita; Joardar, Siddhartha N.; Roy, Barun — Mon, 01 Jan 2007 00:00:00 GMT

The immunostimulatory role of an orally administered yeast cell wall preparation from Saccharomyces cerevisiae (NutrifermTM) was assessed in the Indian major carp, rohu (Labeo rohita). Fish were fed a diet containing the preparation for 15 days and then returned to the con- trol diet for 20 days. Non-specific immunity was assessed at the end of the experimental feed- ing period (day 0) and on days 10 and 20. In vitro oxidative radical production, phagocytosis of leukocytes, nitrite production, and proliferation of lymphocytes were determined. All four para- meters remained stable in control fish but, in fish fed the supplemented diet, reached a peak on day 10 and remained higher than in the control until day 20, indicating that ingestion of the diet containing the yeast cell wall preparation for 15 days had significant immunostimulatory effects.

Effects of n-3 PUFA Levels in Live Foods on Albinism, Growth, Survival, and Salinity Tolerance of Flounder (Paralichthys olivaceus) Larvae in Large-Scale Artificial Rearing

Wel, Wang; Xiangyang, Zou; Feng, Yao; Liqiao, Chen — Mon, 01 Jan 2007 00:00:00 GMT

The effects of feeding enriched rotifers and Artemia nauplii on albinism in flounder (Paralichthys olivaceus) larvae raised in a large-scale artificial system were investigated. Larvae were first fed an S-type rotifer (Brachionus angularis) enriched with Nannochloropsis oculata for 11-12 days, which raised the n-3 polyunsaturated fatty acids (PUFA) content in the rotifer from 5.36% to 17.63% of the total fatty acids. Next, the larvae were fed one of three strains of Artemia enriched with microcapsule (50DE), vitamin A (9000 IU/l), and vitamin D (2000 IU/l) for 35 days, which raised the n-3 PUFA contents in the Artemia to 38.62%, 36.53%, and 33.86% of the total fatty acids, respectively. Among the larvae fed the enriched feeds, no more than 3‰ were albino, much fewer than in the control groups fed non-enriched foods (p<0.01). In addition, n-3 PUFA contents in the muscles, growth and survival rates, and salinity tolerance were greater in founder fed the enriched foods. Artemia nauplii from Qixiangcuo (Tibet, China), enriched to 38.62% of total fatty acids, was superior in preventing albinism than the strains from Pikou or Yingkou (Liaoning, China).

Antibacterial Activity of Oxytetracycline Hydrochloride, Environmentally-Protected or Not, after Feed-Pelleting and during Decay-Dispersion in Saline Water

Laredo, B.S.; Ocampo, C.L.; Sumano, L.H. — Mon, 01 Jan 2007 00:00:00 GMT

Bivalent and trivalent cations quelate oxytetracyline (OTC), rendering it microbiologically inac- tive. Yet shrimp diseases are often treated with OTC in pelleted feeds. Attempts have been made to chemically protect the OTC concentration in shrimp feeds against degradation in brack- ish water and due to temperature. The antibacterial activity of two such environmentally-protect- ed OTC preparations (premixes A and B) and one unprotected OTC premix (C) were tested (a) before and after pelleting the OTC premixes with the powdered feed ingredients and (b) during decay-dispersion of the OTC-medicated feed in brackish water. In all three treatments, the OTC concentration dropped by approximately half after pelleting (p<0.001). When pellets were placed in tanks containing water of 23-25°C, pH 7.6-7.8, and marine salt (40 g/l), a second order expo- nential decay of antibacterial activity followed, reaching 50% in 30 min. At 150 min, loss reached 80% in group A, 85% in group B, and 98% in group C, suggesting that only environmentally-pro- tected OTC may, in some cases, reach the minimal therapeutic concentration necessary to treat Vibrio spp. diseases.

Isolation of Putative Probionts from the Intestines of Indian Major Carps

Ghosh, Shubhadeep; Sinha, Archana; Sahu, Chittaranjan — Mon, 01 Jan 2007 00:00:00 GMT

Probiotic strains were isolated from the intestines of 28 Indian major carps (Labeo rohita, Catla catla, Cirrhinus mrigala) cultured in sewage-fed ponds. Intestinal microflora were isolated, count- ed, and identified, and their in vitro antibacterial properties were determined. The double layer method revealed that four strains (SG1, SG2, SG3, SG4) elicited antagonism against the pathogen Pseudomonas fluorescens. Using cross streak and parallel streak methods, SG4 max- imally inhibited the fish pathogens Pseudomonas fluorescens, Aeromonas hydrophila, and Edwardsiella tarda. Therefore, SG4 was chosen for further study as a probiont. SG4 was non- pathogenic to C. mrigala fingerlings, and adhered well to stainless steel, high density polyethyl- ene, and glass plate substrates. Biochemical tests showed that SG4 was endospore-forming, aer- obic, motile, rod-shaped Bacillus subtilis. However, since in vitro experiments can only give an indication of in vivo success, future research should include large-scale in vivo experiments.

Effects of Early Weaning on Growth and Digestive Enzyme Activity in Larvae of Sea Bass (Dicentrarchus labrax L.)

Suzer, Cuneyt; Firat, Kursat; Saka, Sahin; Karacaogian, Arif — Mon, 01 Jan 2007 00:00:00 GMT

The influence of early weaning on digestive enzymes, growth, and survival in sea bass larvae were investigated. Larvae were reared in a closed sea water system and first fed Artemia nau- plii eight days after hatching. Three weaning periods were compared by introducing a micropar- ticulate diet on day 15, 20, or 25. The control continued to be fed only Artemia. The lowest growth and survival rates were obtained in the 15-day group while the highest were in the 25- day group. After weaning, protease activities (trypsin, chymotrypsin, elastase, pepsin) dropped in all groups, indicating malnutrition. Amylase activity slightly increased in all experimental groups due to the higher starch content in the microparticulate diet than in Artemia and the absolute and relative lipid contents were lower in groups fed the microparticulate diet. Lipase activity suddenly dropped after weaning but slightly rose from day 35 until the end of the exper- iment (day 40). Due to decreased larvae development, survival, and digestive enzyme activity, weaning at 20 days after hatching, synchronous to formation of the stomach and enzymatic activity, is strongly recommended.

Heterosis in the Growth Rate of Hungarian-Israeli Common Carp Crossbreeds and Evaluation of their Sensitivity to Koi Herpes Virus (KHV) Disease

Zak, Tatyana; Perelberg, Ayana; Magen, Igai; Milstein, Ana; Joseph, Dan — Mon, 01 Jan 2007 00:00:00 GMT

Koi herpes virus (KHV) disease first occurred in Israel in spring 1998. In search of genetic solu- tions to the disease, two strains of domesticated common carp (Szarvas-22 and Dinnyes) were imported from Hungary in 2002 to test their genetic contribution to KHV resistance and hetero- sis in growth parameters when crossed with a local strain (Dor-70). During 2004, six genetically different groups were reared, including the three above-mentioned strains and three crossbreeds (Szarvas-22 x Dor-70, Dinnyes x Dor-70, and Nasic x Dor-70). Fish were vaccinated by injection of an inoculum containing attenuated virus, individually marked, stocked in communal earthen ponds, and cultured to market size. Data on resistance to the disease and growth rates were col- lected. The two Hungarian strains and their crossbreeds had no advantage in specific resistance to KHV but contributed to heterosis when crossed with Dor-70. This was expressed by an increase of more than 10% and 20% in growth rate, compared to the commercial Israeli cross- breed (Nasic x Dor-70).

Amino Acid Composition of Heterobranchus longifilis Fry, Fingerlings, and Broodstock

Ovie, Stella O.; Ovie, Solomon — Mon, 01 Jan 2007 00:00:00 GMT

The whole-body amino acid composition of fry, fingerlings, and brood fish of Heterobranchus longifilis was determined using a Technicon Sequential Multisample Auto-Analyser, equipped with a pen recorder for drawing chromatograms. The fish samples consisted of nine essential amino acids (arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threo- nine, valine) and eight nonessential amino acids (alanine, aspartic acid, cystine, glutamic acid, glycine, proline, serine, tyrosine). There were no significant differences among the three stages and all are closely related to those of other fish species.

Rematuration of Spent Macrobrachium rosenbergii Female Broodstock through Dietary Manipulation and Eyestalk Ablation

Murmu, Khuntia; Sahu, N.P.; Mallik, S.K.; Reddy, A.K.; Kohli, M.P.S. — Mon, 01 Jan 2007 00:00:00 GMT

The single or combined effects of artificial feed and eyestalk ablation on gonadal maturation of spent Macrobrachium rosenbergii female brooders was studied in 48 females. Significant differ- ences in percent weight gain, food conversion ratio, specific growth rate, gonado-somatic index, number of molts, molting interval, and ovarian development stages were observed. The highest numbers of molts and shortest molting intervals were found in eyestalk-ablated groups while higher percent weight gains were obtained in non-ablated groups. Groups fed formulated feed registered lower percent weight gains and higher FCRs than groups fed natural feed (clam and squid meat). Females in immature stages were found only in non-ablated groups while the only ovigerous females were found in the ablated group fed formulated feed. In short, unilateral eye- stalk ablation together with properly formulated feed (46.1% crude protein) could induce gonad maturation of spent female Macrobrachium rosenbergii brooders during the non-monsoon sea- son.