Naser Agh

Publications (49) View all

• Article: Sediment cores from Lake Urmia (Iran) suggest the inhabitation by parthenogenetic Artemia around 5,000 years ago

  R. Manaffar, S. Zare, N. Agh, A. Siyabgodsi, S. Soltanian, F. Mees, P. Sorgeloos, P. Bossier, G. Van Stappen
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  ABSTRACT: In Lake Urmia area, northwestern Iran, parthenogenetic Artemia and the bisexual Artemia urmiana Günther 1890 are found to occupy different ecological niches determined by salinity. Given the fluctuations of the lake over geological times, we thus hypothesized that species identification of Artemia cysts, buried in the sediments, can provide information on lake conditions in the past. Therefore, encysted embryos of Artemia were recovered from lake sediments by augering at a site near the present shoreline. Cysts and associated plant remains from two studied levels yielded radiocarbon ages in the range 5,000–6,700 YBP. For determination of the type of Artemia, the constant synonym mutation in exon-7 of the Na/K ATPase gene was verified, and the diameter of the recovered cysts was compared with that of modern cysts from the Lake Urmia region. The results show that the cysts represent a parthenogenetic type of Artemia, whose cyst diameter is somewhat different from that of present-day local parthenogenetic Artemia. The present study firstly confirms the stability of DNA in ancient Artemia cysts for molecular analysis. Moreover, it suggests variation in Lake Urmia’s conditions over time, and based on comparison with salinity preferences of contemporary Artemia populations, it more specifically suggests that Lake Urmia was a brackish lake dominated by a parthenogenetic Artemia population in the geological period sampled. It finally illustrates how, like in the study of freshwater propagule banks, paleogenetic analysis of Artemia DNA recovered from sediment cores can be used as a tool in the paleoecological study of generally highly fluctuating saline habitats. KeywordsArtemia–Ancient cysts–Lake Urmia–Na/K ATPase gene
  Hydrobiologia 04/2012; 671(1):65-74. · 1.78 Impact Factor
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  Available from: Mohammad Sedigh Jasour

  Article: A survey on the Effect of Bovine Lactoferrin on the Growth Parameters of Rainbow Trout (Oncorhynchus mykiss)

  M. Lotfi, N. Agh, M. Shamsaei, R. Malekzadeh viayeh, M. Mohammadi zadeh, M. S. Jasour
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  ABSTRACT: In this study, the effect of bovine lactoferrin (Lf) on growth parameters of rainbow trout (Oncorhynchus mykiss) were investigated. Fish with mean body weight of 40±5 g were fed for 30 days on three feeding regimes (1) commercial diet supplemented with 200 mg Lf/kg (2) commercial diet supplemented with 100 mg Lf/kg, (3) commercial diet without Lf. Growth and nutritional parameters were measured at the end of the experiment. Results revealed that the fish in all experimental treatments fed by LF, had significantly higher SGR, weight gain and lower FCR compared to the fish in control group (P <0.05). Fish fed on the diet containing 200 mg LF/kg exhibited higher growth parameters except condition factor, but no significant differences were observed with the group fed on diet supplemented with 100 mg LF/kg (P>0.05). The results indicated that use of 100 mg Lf/kg diet is highly recommended for feeding rainbow trout.
  RENEWABLE NATURAL RESOURCES RESEARCH. 01/2012;
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  Available from: Naser Agh

  Article: First feeding strategy for hatchery produced Beluga sturgeon, Huso huso larvae

  N Agh, Noori, A Irani, N M Makhdom
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  ABSTRACT: Co-feeding of fish larvae with live food and formulated diet has been at the focus of fish nutritionists since last decade. In this study we tried to refine the feeding practices of great beluga sturgeon (Huso huso) larvae using different combinations of newly hatched Artemia urmiana nauplii and trout starter diet. Three replicate groups (250 fish/replicate) of first-feeding Huso huso larvae were fed on the basis of four main feeding regimens: (1) live food (live nauplii of brine shrimp Artemia urmiana); (2) indirect transition (5 days live food followed by gradual transition to formulated diet); (3) direct transition (using different combinations of live and formulated diet from start feeding); (4) formulated feed (FD). It was found that combining live food and manufactured diets (co-feeding) from first feeding stage (direct transition) significantly improves the weight gain in H. huso larvae followed by indirect transition, live food and FD. But survival was significantly higher in larvae fed on pure live food and direct transition regimens compared to indirect transition and FD. It was concluded that co-feeding of H. huso could be started immediately from commencement of exogenous feeding.
  Iranian Journal of Fisheries Sciences 01/2012; 11(4):713-723. · 0.98 Impact Factor
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  Available from: Naser Agh

  Article: Body shape changes during the early development of the Beluga (Huso huso)

  Reza Asgari, Soheil Eagderi, Gholamreza Rafiee, Hadi Poorbagher, Naser Agh, Hamid Eshagh Zadeh
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  ABSTRACT: Early body shape changes of beluga sturgeon were studied using landmark-based geometric morphometric approach to recognize its allometric growth pattern. Sampling was done from hatching up to 50 days post hatching (DPH). Left side of specimens were photographed using digital camera and nine landmark points were digitized on two-dimensional images. Total length (TI) was measured using the software ImageJ. To study of the body shape changes during early development, the mean procrustes distance between all specimens of same age, for all age groups, was calculated. The scores of relative warp analysis (RW) were used as descriptors for the variation in shape. RW analysis revealed a sharp body shape change during early ontogeny on 18 DPH. Growth trajectory was computed by plotting RW against TL. The inflection point of body shape corresponds to a TL of 23.3 mm (18 DPH). Results showed that ontogenetic shape changes encompassed a pre-inflection shape changes, which included the elongation of the head and tail regions i.e. positive allometric growth pattern and post-inflection shape changes, with a nearly isometric growth pattern. Introduction The early development of fish larvae is accompanied with very complex shape changes. Different growth rates of various parts of the body or allometric growth is a common phenomenon during this period (Osse and van den Boogaart, 1995). During the early development, changes in body shape are related to the functions of different organs such as respiration, feeding and swimming (Simonovic et al., 1999; Russo et al., 2007). Recognition of morphogenesis process and growth pattern of fishes may lead to better understanding of biological priorities during the early developmental stages and gives insights into biological, behavioral and ecological characteristics (Gisbert, 1999). Many studied have been carried out on change of the body shape during the early ontogeny of various fishes using traditional morphometric approaches but recently, geometric morphometric techniques
  International Journal of Aquatic Biology. 03/2013; 2013(1):1-5.
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  Available from: Naser Agh

  Article: Effects of Salinity and Ultraviolet Radiation on the Bioaccumulation of Mycosporine-like Amino Acids in Artemia from Lake Urmia (Iran)

  Sanaz Khosravi, Saber Khodabande, Naser Agh, Mahdieh Bakhtiarian
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  ABSTRACT: We investigated the effects of salinity and artificial UV radiation on the accumulation of mycosporine-like amino acids (MAAs) in sexual and parthenogenetic Artemia from Lake Urmia. The nauplii hatched from the cysts were cultured until adulthood under two salinities (150 and 250 g L�1) and two light treatments (PAR and PAR+UVR) in the laboratory. Finally, the Artemia were analyzed for their concentration of MAAs. In most of the cases, the higher salinity level applied was found to increase the MAA concentrations in both Artemia populations significantly. The acquisition efficiency of MAAs in both Artemia populations increased under exposure to UVR-supplemented photosynthetically active radiation (PAR) compared to those raised under PAR, except for Porphyra- 334. It was observed that combination of UV radiation and elevated salinity significantly increased the bioaccumulation of MAAs. Thus, the presence of these compounds in these populations of Artemia may increase their adaptability for living in high-UV and high-salinity conditions prevailing in Lake Urmia. Higher concentrations of MAAs in the parthenogenetic population of Artemia could be probably attributed to its mono sex nature and higher adaptation capacities to extreme environmental conditions.
  Photochemistry and Photobiology 01/2013; 89:400-405. · 2.41 Impact Factor