İbrahim Diler

PCR detection of the crayfish plague pathogen in narrow-clawed crayfish inhabiting Lake Eğirdir in Turkey

Many populations of the narrow-clawed crayfish Astacus leptodactylus in Turkey, including those inhabiting Lake Eğirdir, declined drastically in the mid-1980s due to introduction of crayfish plague Aphanomyces astaci. However, unlike many other localities, there has been some recovery in the A. leptodactylus population inhabiting this lake even though crayfish plague has been suspected to have persisted since then. In support of this, DNA from 5 of 34 healthy-looking crayfish sampled recently from the lake tested positive by both conventional and real-time PCR using species-specific primers targeting the rDNA internal transcribed spacer region, and product sequence analysis confirmed the identification of A. astaci. This complies with other recent reports of coexistence of native European crayfish with this pathogen, and further research is now needed to identify the key mechanisms allowing it.

Effect of protease and phytase supplementation on growth performance and nutrient digestibility of rainbow trout (Oncorhynchus mykiss, Walbaum) fed soybean meal-based diets

ABSTRACT An experiment was conducted to evaluate effects on growth, body composition and nutrient digestibility of addition protease and phytase to soybean meal-based diet in rainbow trout. Seven soybean meal-based diets were prepared by adding protease, phytase and mixture of both enzymes at two different levels (1 and 2 g kg−1) to a base diet without enzymes. Mixed enzymes (1, 2 g kg−1) were prepared by adding protease and phytase at the same doses (0.5 + 0.5 and 1 + 1 g kg−1). Diets consisted of 31% fish meal and 44% dehulled hexane extracted soybean meal. At the start of the experiment, 45 rainbow trout (initial mean body weight 88 g) were stocked into each of 21 fibre tanks. After 90 days, there were no significant differences on the growth, feed conversion ratio, digestibility of protein and lipid among the groups. Results of this study showed that the addition of protease or phytase as mix to soybean meal-based diet could not increase growth and nutrient digestibility in trout.

Effect of β-Mannanase and α-Galactosidase Supplementation to Soybean Meal Based Diets on Growth, Feed Efficiency and Nutrient Digestibility of Rainbow Trout, Oncorhynchus mykiss (Walbaum).

A 12-week feeding trial was conducted with 87 g rainbow trout to evaluate the effects on growth performances, feed efficiency and nutrient digestibility of adding β-mannanase and α-galactosidase enzymes, solely or in combination. Seven diets were prepared by adding β-mannanase, α-galactosidase and mixed enzyme at two different levels (1 g/kg and 2 g/kg) to control diet (without enzyme) including soybean meal. Mixed enzymes (1 g/kg, 2 g/kg) were prepared by adding β-mannanase and α-galactosidase at the same doses (0.5+0.5 g/kg and 1+1 g/kg). At the end of the experiment, addition of β-mannanase, α-galactosidase and mixed enzyme to diet containing 44% soybean meal had no significant effects on growth performance and gain:feed (p>0.05). In addition, adding β-mannanase, α-galactosidase and mixed enzyme in different rations to trout diets had no affect on nutrient digestibility and body composition (p>0.05).

GÖKKUŞAĞI ALABALIĞI (Oncorhynchus mykiss) YEMLERİNE FARKLI ORANLARDA İLAVE EDİLEN KANTARON YAĞININ (Hypericum perforatum) BÜYÜME PERFORMANSI, BAZI ÇEVRESEL STRES PARAMETRELERİ VE ANTİOKSİDAN AKTİVİTESİ ÜZERİNE ETKİLERİ

 Bu calismada juvenil gokkusagi alabaligi ( Oncorhynchus mykiss ) yemlerine ilave edilen sari kantaron ( Hypericum perforatum ) yaginin buyume performansi, bazi cevresel stres parametreleri ve antioksidan aktivitesi uzerine etkileri arastirilmistir. Calisma 0 mL/kg (kontrol grubu) ve 1 mL/kg, 2 mL/kg, 3 ml/kg oranlarinda kantaron yagi iceren yem gruplari ile 3 tekerrurlu olarak olusturularak 500 litrelik dikdortgen fiberglas tanklarda 20g ortalama baslangic agirligina sahip juvenil alabalik bireyleriyle 90 gun boyunca surdurulmustur. Deneme sonucunda elde edilen parametrelerden, toplam ortalama canli agirlik artisi 88,86-90,97 (g), spesifik buyume orani 1.85-1.86 ( % gun -1 ) , yem donusum orani 1.02-1.07, yasama orani %97-100, yem donusum etkinligi 98.89-100.05, kondisyon faktoru 1.23-1.24, total antioksidan duzeyi 1.96-2.07 (µmol Trolox equivalents/L), total oksidan duzeyi 1,10-1,70 (µmol H 2 O 2 equivalent/L), oksidatif stres indeksi 56.15-81.44 (TOS/TAS*100), glikoz duzeyi 73.00-76.66 (mg/dL), kortizol duzeyi 0.78-1.13 (µ/dL), lizozim enziminin olusturdugu zon capi 0.90-1.08 (cm) araliklarinda belirlenmistir. Yem gruplarinin total oksidan duzeyi ve oksidatif stres indeksi parametreleri istatistiksel acidan farklilik gostermistir (p 0.05) oksidan duzeyi ve oksidatif stres indeksi duzeylerinde olumlu etkiler gozlenmistir.