Seval Bahadir Koca

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.

New Bythinella (Gastropoda, Bythinellidae) species from western Turkey.

Abstract Bythinella anatolica sp. n., Bythinella istanbulensis sp. n., Bythinella magdalenae sp. n., and Bythinella wilkei sp. n. from western Turkey are described herein. Illustrations of the shell and genitalia of the newly described taxa, together with comparisons with previously known Bythinella taxa and a key to the species from western Turkey, are also provided.

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).

Farklı Yem ve Stok Yoğunluğunun Astacus leptodactylus (Esch., 1823) Juvenillerinin Hayatta Kalma ve Büyüme Performansı Üzerine Etkisi

Bu calismada, iki farkli yem (canli yem- Daphnia magna ve ticari alabalik yemi) ve stok yogunlugunun (650 ve 1300 juvenil/m 2 ) Astacus leptodactylus yavrularinin hayatta kalma ve buyume performansi uzerine kombine etkileri arastirilmistir. Denemede II. donem yavrular kullanilmistir. Deneme sonunda, yavrularin hayatta kalma ve buyume parametreleri degerlendirilmistir. Bu calismanin sonuclari, diyetlerin hayatta kalma oranlari uzerinde etkili olmadigini, ancak artan stok yogunlugunun yasama oranlarini azalttigini gostermistir. En iyi yasama orani % 21,99 olarak 650 juvenil/m 2 stok yogunlugunda canli yemle beslenen grupta saglanirken, en dusuk yasama orani ise % 10,84 olarak 1300 juvenil/m 2 stok yogunlugunda alabalik yemi ile beslenen grupta elde edilmistir. Denememe sonunda en yuksek vucut agirligi, 650 juvenil/m 2 stok yogunlugunda alabalik yemi ile beslenen grupta bulunmustur. Calismamiz sonucunda ayrica, yavru kerevit beslenmesinde her iki yem ile beslenen yavrularda hayatta kalma oranlari uzerinde stok yogunlugunun onemli bir etkiye sahip oldugu gorulmustur.