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    Öğe
    Dietary Carbohydrate Level Influencing Feed Intake, Nutrient Utilisation and Plasma Glucose Concentration in the Rainbow Trout, Oncorhynchus mykiss
    (2001) Tekinay, Ahmet Adem; Davies, Simon John
    A twelve-week nutrition trial was carried out to evaluate the efficacy of different carbohydrate levels on digestibility, feed intake, growth performance, carcass and muscle composition and plasma glucose level in the rainbow trout. Oncorhynchus mykiss. Three test diets were formulated using extruded wheat meal (15.3. 32.2 and 43.5%) as the carbohydrate source and fed rainbow trout (Initial Body Weight 33.8 ± 0.46 g.). These were either restricted: LCR (Low Carbohydrate Restricted). MCR (Medium- Carbohydrate-Restricted) and HCR (High-Carbohydrate Restricted); or satiation: LCS (Low- Carbohydrate Satiation), MCS (Medium- Carbohydrate Satiation) and HCS (High-Carbohydrate Satiation) respectively. The aim of applying different feeding regimes was to quantify the protein sparing effect of carbohydrate and to determine the response of rainbow trout to different levels of carbohydrates. The results showed that protein, energy and carbohydrate digestibility was reduced with increasing dietary carbohydrate levels, whilst lipid digestibility was similar all the groups. There was a significant energy substitution from the carbohydrate source in the restricted groups. However, since the maximum feeding rate was reached in the restricted regimes (MCR and HCR), a similar sparing action of carbohydrate was observed in the satiation groups (MCS and HCS). All the groups displayed good growth performance, and exhibited growth that was LCS exhibited the highest (P< 0.05) growth rate. MCR and MCS trout exhibited growth that was superior (P< 0.05) to that of the LCR, HCR and HCS treatments. The feed efficiency of all the treatments was close to 100%. The quantities of carcass and muscle protein, lipid and ash were not found to be different (P> 0.05). Transient hyperglycaemia was observed in trout fed a high carbohydrate diet These results are discussed with respect to the protein sparing action of dietary carbohydrate in practical trout diets and the possible physiological effects of carbohydrates on feed intake regulation.
  • [ X ]
    Öğe
    Dietary carbohydrate level influencing feed intake, nutrient utilization and plasma glucose concentration in the rainbow trout, Oncorhynchus mykiss
    (2001) Tekinay, Ahmet Adem; Davies, Simon John
    A twelve-week nutrition trial was carried out to evaluate the efficacy of different carbohydrate levels on digestibility, feed intake, growth performance, carcass and muscle composition and plasma glucose level in the rainbow trout, Oncorhynchus mykiss. Three test diets were formulated using extruded wheat meal (15.3, 32.2 and 43.5%) as the carbohydrate source and fed rainbow trout (Initial Body Weight: 33.8$\\pm$ 0.46 g.). These were either restricted: LCR (Low Carbohydrate Restricted), MCR (Medium-Carbohydrate-Restricted) and HCR (High-Carbohydrate Restricted); or satiation: LCS (Low-Carbohydrate Satiation), MCS (Medium-Carbohydrate Satiation) and HCS (High-Carbohydrate Satiation) respectively. The aim of applying different feeding regimes was to quantify the protein sparing effect of carbohydrate and to determine the response of rainbow trout to different levels of carbohydrates. The results showed that protein, energy and carbohydrate digestibility was reduced with increasing dietary carbohydrate levels, whilst lipid digestibility was similar all the groups. There was a significant energy substitution from the carbohydrate source in the restricted groups. However, since the maximum feeding rate was reached in the restricted regimes (MCR and HCR), a similar sparing action of carbohydrate was observed in the satiation groups (MCS and HCS). All the groups displayed good growth performance, and exhibited growth that was LCS exhibited the highest (P< 0.05) growth rate. MCR and MCS trout exhibited growth that was superior (P< 0.05) to that of the LCR, HCR and HCS treatments. The feed efficiency of all the treatments was close to 100%. The quantities of carcass and muscle protein, lipid and ash were not found to be different (P> 0.05). Transient hyperglycaemia was observed in trout fed a high carbohydrate diet. These results are discussed with respect to the protein sparing action of dietary carbohydrate in practical trout diets and the possible physiological effects of carbohydrates on feed intake regulation.
  • [ X ]
    Öğe
    Effects of dietary carbohydrate level on gastric evacuation and return of appetite in the rainbow trout, Oncorhynchus mykiss
    (2002) Tekinay, Ahmet Adem; Davies, Simon John
    Yem karbonhidrat oranlarının alabalıkların, Oncorhynchus mykiss, mide boşalım ve yem alma isteğine dönüş süresi üzerine etkilerini araştırmak amacıyla, % 14.9 (düşük karbonhidrat; DK), % 31.4 (orta karbonhidrat; OK) ve % 42.3 (yüksek karbohidrat; YK) oranlarında ekstrude edilmiş buğday unu içeren yemler deneme balıklarına yedirilmiştir. Mide boşalım çalışmaları, balıklar belirli zaman aralıklarında öldürülüp mide içerikleri çıkartılarak gerçekleştirilmiş, yem alma isteğine dönüş süreleri de X-Radiyografi metodu kullanılarak tahmin edilmiştir. Her üç grubun mide boşalım verileri en iyi karekö k (square root) eşitlikleriyle açıklanmıştır. DK grubunun mide boşalım oranı OK ve YK balıklarının oranlarından önemli derecede (P<0.05) farklı bulunurken, aynı parametrenin, OK ve YK grupları arasında farklılık göstermediği (P>0.05) belirlenmiştir. Deneme gruplarının yem alma isteğine dönüş oranları üç adet sigmoid model ile açıklanmıştır. Tespit edilen parametrelerden, yem-karbonhidrat oranına bağlı olmaksızın, alabalıkların mide boşalım ve yem alma isteğine dönüş oranları arasında oldukça yakın bir ilişki saptanmıştır. Bu sonuçlara göre, kısa süreli iştah kontrolünde, alabalıkların yem kompozisyondan bağımsız olarak midelerini doldurmak için yem tükettikleri iddia edilmiştir.
  • [ X ]
    Öğe
    The efficacy of different size of X-ray dense markers for determination of sequential feeding rates in rainbow trout (Oncorhynchus mykiss Walbaum, 1792)
    (2001) Tekinay, Ahmet Adem; Davies, Simon John
    Bir kapalı devre tatlı su sisteminde, 30 tane yetişkin gökkuşağı alabalığı, (O. mykiss) (202.1 ±3.5 gr) içinde küçük X-ışmı yansıtan cam bilye (ballotini) (0.6-0.9 mm çapında) bulunan ilk test yemiyle doyuncaya kadar beslenmişlerdir. Yemlemeyi takiben farklı zaman aralıklarında (z= O, 4, 8, 12, 24, 30 ve 36 saat) içinde büyük cam bilye (1.16-1.14 mm) içeren ikinci test yemiyle beslenerek röntgenleri çekilmiştir. Her zaman aralığında balıklar tarafından tüketilen yem miktarları röntgen filmlerinde belirlenen cam bilyelerin sayılması ile hesaplanmış ve alabalıkların iştaha dönüş oranları modellenmiştir. Yem tüketim verileri en uygun şekilde bir birinci mertebe (first order) eşitlik tarafından açıklanmıştır (Yem Tüketimi = 106.26* (l-e\" 0.079'zaman^ ßu modele görej aıabalıklarm % 50 iştaha dönüş süresi 8 saat, % 95 iştaha dönüş süresi ise 28 saat olarak tahmin edilmiştir. Değişik kaliteye sahip yemlere farklı büyüklüklerde cam bilye ilave etmek suretiyle 12 saatlik bir periyot içinde, söz konusu yemlerin aynı anda veya aralıklı şekilde tüketildikleri miktarların saptanabileceği savunulmuştur.