A Preliminary Study on Protease Activity of Russian Sturgeon, Acipencer gueldenstaedtii Brandt and Ratzenburg, 1833, at Early Life Stages

The fish feed industry continues to researches for optimum diet demands for candidate species culture. For this purpose, in vitro analyze methods may be more efficient than in vivo assays. This study includes two different stages; the first one is about the effect of commercial feeding protocol on protease enzyme alteration and the second one is about the inhibitory effects of different protein sources on early life proteases of Russian sturgeon, A. gueldenstaedtii, juveniles. In the first step, feeding with live prey and transition period to artificial feed significantly affected the daily amount of protease in digestive system ( P < 0.05). In the second part, some protein sources used in micro diets were tested in vitro for examination of their possible inhibitory effects on the proteases of Russian sturgeon larvae. The minimum inhibitory effect was obtained from fish meal (15.44%), but however, soybean protein concentration, soybean meal, corn gluten and rice bran inhibited the proteases significantly higher than FM and its combinations (63.55, 71.81, 72.24, and 80.77%, respectively). Additionally, dual combinations between fish meal and soybean meal/soybean protein concentration with the ration of three to one ( 3: 1) was moderate (26.38 and 22.13 %), whereas blood meal extremely produced a 97.28% inhibitory ratio

An alternative species for traditional carp polyculture in Turkey : Initial growing period

Himri Barbel fry (Barbus luteus, Heckel 1843) were introduced to traditional carp polyculture under controlled indoor laboratory conditions. Five treatment groups were designed according to different stocking proportions of carp and himri and each treatment were triplicated. The study was carried out for 90 days by using 100-L aquariums and fish were fed three times a day by commercial carp diet. Five stocking treatments were as follow: S1 (100% common carp), S2 (75% common carp+25% himri barbel), S3 (50% common carp+50% himri barbel), S4 (25% common carp+75% himri barbel), and S5 (100% himri barbel). Polyculturing with carp had no adverse effects on himri stocks and vice versa

The characterization and activity of protease enzyme on different days of Tadpoles [Pelophylax ridibundus (Pallas, 1771)]

In this study, protease enzyme activity of Pelophylax ridibundus (Pallas, 1771) tadpoles was determined during the larval period starting from 25 Gosner stage (1960). When the P. ridibundus tadpoles reached the 25 Gosner stage (1960) on the 22nd day, the sampling was continued until the metamorphosis was completed by sampling at 5-day intervals. Initial average weight and length of the tadpoles were 0.076 g and 6.42 mm, respectively. The tadpoles were fed with pellet feed the size of 2 mm and 39% crude protein content twice a day in the morning and afternoon. The differences in the protease activity between the 22nd day and the 62nd day of the metamorphosis were found statistically significant (P<0.05). It has been observed that the protease enzyme reached maximum level at the 32nd day. In the next stages, protease activity showed a tendency to increase and decrease up to metamorphosis. These results can be used as the basis for the most appropriate nutritional formulation for P. ridibundus in the larval stage

Farklı Protein Kaynaklarının Çuka Mersini, Acipenser ruthenus Linnaeus 1758, Juvenillerinde Proteaz Aktivitesi Üzerine Etkileri

Bu çalışmada, çuka balığı, Acipenser ruthenus,  larvaları yumurtadan çıkış anından itibaren 29 gün boyunca standart besleme protokolü ile beslenmiştir. Karma yeme geçiş yapılan 29. gündeki proteolitik aktivite ve farklı protein kaynaklarının proteaz aktivite üzerine inhibisyon etkileri ölçülmüştür. Çalışmadan elde edilen bilgiler ışığında, çuka balığı juvenillerinin karma yemlerinde protein kaynağı olarak soya protein konsantresi (%38,57±10,44) ve mısır gluten (%43,07±1,72) kullanmanın, diğer yem hammaddeleri ile karşılaştırıldığında, proteolitik enzim aktivitesini istatistiki açıdan daha olumlu etki yaptığı görülmüştür (P&lt;0,05). Yem hammaddelerinin ikili kombinasyonları incelendiğinde ise, en düşük inhibisyon oranı balık unu: soya protein konsantresinin 1:1 oranda kullanılması (%47,93±1,72) ile elde edilmiş ve bu değerin soya protein konsantresi ve mısır gluteninin tek başlarına kullanılması ile elde edilen etki ile aynı seviyede olduğu tespit edilmiştir (P&gt;0,05). En yüksek inhibe edici etki ise, buğday ile pirinç kepeğinin 3:1 oranda kullanılması ile oluşmuştur (%82,39±7,23)

Sarıbenli (Barbus luteus Heckel, 1843) Balığının Asi Nehrindeki (Türkiye) Yaş ve Büyüme Özellikleri

In this study, the age and growth of Himri Barbel (Barbus luteus Heckel, 1843) were determined based on specimens collected from Orontes River-Turkey, during the period from February 2004 to January 2005. This population comprised 7 age groups of males and 9 of females. The male and female ratio was 1:1.26 (M:F). Total length-weight relationship was estimated as W = 0.0129TL2.986 for females, W = 0.0125TL3.003 for males. Growth parameters of the von Bertalanffy equation were computed for females and males as: L∞= 38.77, W∞= 714.23, k = 0.300, t0 = -1.69 and L∞ = 40.32, W∞ = 819.35, k = 0.247, t0 = -1.58, respectively. Maximum observed age was 9, suggesting that the species is long-lived.Bu çalışmada, Asi nehrinden avlanan Sarıbenli (Barbus luteus) balığının Şubat 2004 - Ocak 2005 tarihleri arasındaki yaş ve büyüme özellikleri belirlenmiştir. Populasyon, erkek bireylerde 7, dişi bireyler ise 9 yaş grubunu kapsamaktadır. Erkek-dişi birey oranı 1:1,26 (E:D) olarak bulunmuştur. Toplam boy-ağırlık ilişkisi dişiler için W = 0,0129TL2.986, erkekler için ise W = 0,0125TL3.003 denklemleriyle tahmin edilmiştir. Von Bertalanffy büyüme parametreleri dişilerde: L∞ = 38,77, W∞ = 714,23, k=0,300, t0 = -1,69 ve erkeklerde L∞ = 40,32, W∞ = 819,35, k = 0.247, t0 = -1,58 olarak tespit edilmiştir. Gözlenen en büyük yaş 9 olup, türün uzun yaşayan bir tür olduğu düşünülmektedi