Oya Işık

Comparison of the fatty acid composition of the freshwater fish larvae Tilapia zillii, the rotifer Brachionus calyciflorus, and the microalgae Scenedesmus abundans, Monoraphidium minitum and Chlorella vulgaris in the algae-rotifer-fish larvae food chains

Abstract The proximate and the fatty acid analysis of the warm freshwater fish, Tilapia zillii larvae, the freshwater rotifer Brachionus calyciflorus and the microalgae Scenedesmus abundans , Monoraphidium minitum and Chlorella vulgaris each constituting a different food chain with B. calyciflorus and T. zillii larvae have been carried out. C. vulgaris had significantly higher lipid content than the other two microalgae and this was also reflected in the lipid content of B. calyciflorus fed each of the microalgae separately. Five fatty acids dominated in all the microalgae, namely 18:3 n −3, 18:2 n −6, 18:0, 18:1 and 16:0 though there were significant differences both in quantitative distribution of these acids and the total fatty acid content. The content of 18:3 n −3, 18:2 n −6 and 16:0 and the total fatty acid content of C. vulgaris were considerably higher than the corresponding values in the other two microalgae. But interestingly, these strong differences were not reflected in B. calyciflorus samples fed these microalgae separately though the one fed C. vulgaris had slightly higher total fatty acid content than the other two rotifer samples. One can consider that the freshwater rotifer B. calyciflorus is capable of creating its own characteristic fatty acid content up to a sufficient level even when cultured with a fatty acid deficient algae probably by consuming excessive amounts of this algae compared to other algae of relatively high fatty acid content. The proximate and fatty acid analysis results of the three T. zillii larvae fed the three B. calyciflorus samples obtained by culturing with three different microalgae were very similar. This was an expected result because the three B. calyciflorus samples did not differ much from each other. The low 18:2 n −6 (1.66–3.53 mg g −1 DM) and 18:3 n −3 (1.14–1.22 mg g −1 DM) content and the relatively high 22:6 n −3 (10.72–14.38 mg g −1 DM) content of the T. zillii larvae samples indicated that they were capable of elongating and desaturating both linoleic and linolenic acids of the B. calyciflorus samples.

Photon irradiance required to support optimal growth and interrelations between irradiance and pigment composition in the green alga Haematococcus pluvialis

The aim of the work was to find the optimal photon irradiance for the growth of green cells of Haematococcus pluvialis and to study the interrelations between changes in photochemical parameters and pigment composition in cells exposed to photon irradiances between 50 and 600 µmol m−2 s−1 and a light:dark cycle of 12:12 h. Productivity of cultures increased with irradiance. However, the rate of increase was higher in the range 50–200 µmol −2 s−1. The carotenoid content increased with increasing irradiance, while the chlorophyll content decreased. The maximum quantum yield of PSII (Fv/Fm) gradually declined from 0.76 at the lowest irradiance of 50 µmol −2 s−1 to 0.66 at 600 µmol −2 s−1. Photosynthetic activity showed a drop at the end of the light period, but recovered fully during the following dark phase. A steep increase in non-photochemical quenching was observed when cultures were grown at irradiances above 200 µmol −2 s−1. A sharp increase in the content of secondary carotenoids also occurred above 200 µmol m−2 s−1. According to our results, with H. pluvialis green cells grown in a 5-cm light path device, 200 µmol −2 s−1 was optimal for growth, and represented a threshold above which important changes in both photochemical parameters and pigment composition occurred.

Effect of Different Diets on Growth of Blackmoli (Poecilia latipinna) Larvae

Abstract Tekelioglu, N., Uslu, M. and Isik, O. 2005. Effect of different diets on growth of Blackmoli (Poecilia latipinna) larvae. J. Appl. Anim. Res., 28: 45–47. Performance of Blackmoli (Poecilia latipinna) larvae were tested using four different types of foods. Larvae (1 wk, 19.8±0.87 mg) were fed microalgae Spirulina, rotifer Brachionusplicatilis, Artemia and an artificial diet. At the end of 21 days of culture period the best performance in the form of liveweight gain and survival rate of larvae was observed on Spirulina diet.

Bioavailability of iron speciations and EDTA-iron complexes for Thallassiosira weissflogii (Bacillariophyta)

This study aimed to determine the effects of daily and/or initial additions of various amounts of Fe (II) and Fe (III), in combination with or without EDTA, on the growth of Thalassiosira weissflogii cultures. The results reveal that growth parameters were higher in the cultures containing 5000 nM Fe(III) ± EDTA than those of 5 nM Fe(III) and Fe(II). T. weissflogii cells seemed not to have used EDTA-bound iron, but their own released ligand to bind iron when Fe(III) concentration was high, and to have preferred inorganic Fe(II). Cell abundance and chl-a level were higher in daily supplemented cultures, with regard to those supported with iron only initially, evidencing the importance of continuous supply of iron in chl-a synthesis. Key Words : Thallassiosira weissflogii , iron speciation, EDTA, growth.

Mikroalglerde Kuru Madde Miktarı ile İlişkili Faktörlerin Doğrudan ve Dolaylı Etkilerinin İncelenmesi

Lipid uretimi ile bilinen mikroalg Phaeodactylum tricornutum kulturlerinde kuru madde miktarini etkileyen isik ve sicaklik faktorlerinin yaninda klorofil a ve optik yogunluk analiz ve olcumleri urun verimliligi ile dogrudan ya da dolayli olarak iliskilidir. Bu calismada, kuru maddeyi miktari ile iliskili faktorlerden onemli olani belirlemek icin path analizi kullanilmistir. Analize dahil edilen faktorler optik yogunluk, klorofil a , sicaklik ve isik siddetidir. Phaeodactylum tricornutum , en uygun besi ortaminda kontrol grubu olarak ve ortamdan %50 azot (N) eksiltildigi besi ortaminda fotobiyoreaktorlerde kulture alinmistir. Calismanin sonucunda, kontrol grubunda kuru madde miktari tahmininde en yuksek dogrudan etkiye sahip faktor optik yogunluk, en yuksek dolayli etkiye sahip faktor ise isik siddeti olarak bulunmustur. %50 oraninda azot eksiltilen ortamda ise birden buyuk path katsayisi bulunmustur. Sicaklik ve klorofil a degiskenlerinin ise dogrudan ve dolayli etkilerinin dusuk oldugu gozlemlenmistir.

Outdoor culture and polysaccharide extraction of Porphyridium purpureum in flat panel reactor system

Calismada Porphyridium purpureum turu disari ortamda farkli isik yolu uzunluguna (3, 5, 7 cm) sahip duz panel fotobiyoreaktor sistemlerinde kulture alinmistir. Lipid, protein, biyomas ve polisakkarit miktarlari belirlenmistir. Porphyridium purpureum turu icin en yuksek polisakkarit miktari (0,48 gL -1 ), 1,316 gL -1 biyomas ve %29,7 protein icerigi ile 3 cm isik yolu uzunluguna sahip duz panel photobiyoreaktor sistemde belirlenmistir. En dusuk polisakkarit miktari 0,31 gL -1 ve en yuksek protein %32,3 ile 7 cm isik yoluna sahip photobiyoreaktor sistemde belirlenmistir. Sonuc olarak, Porphyridium purpureum turunun Cukurova (Adana, Turkiye) kosullarinda uretimi, panel sistemlerde basarili bir sekilde tamamlanmistir. En iyi buyume 3 cm isik yoluna sahip panel fotobiyoreaktorde elde edilmistir.