Browsing by Subject "Karpfenzucht"

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    Jatropha meal and protein isolate as a protein source in aquafeed
    (2011) Kumar, Vikas; Becker, Klaus
    As aquaculture continues to develop, there will be an increasing need to use alternative plant proteins in aquaculture diets so that aqua eco-systems will be sustainable. Jatropha (DJKM, H-JPKM and DJPI) can be used as protein rich sources in the diets of fish and shrimp. There is a high potential for the safe use of DJKM, H-JPKM and DJPI in diets for fish and shrimp without compromising performance, provided that these ingredients are free of toxic factors. The detoxification process developed in Hohenheim is simple and robust and produces products that are safe and of good quality. Their addition to fish and shrimp diets gave excellent performance responses without any ill effects on animal health or safety. Effects on growth and nutrient utilization: ? Detoxified Jatropha kernel meal, H-JPKM and DJPI could replace 50%, 62.5% and 75% fish meal protein respectively without compromising growth performance and nutrient utilization in fish. In addition, DJKM could also replace 50% fish meal protein with no adverse effects on growth and nutrient utilization in shrimp. If the replacement levels are exceeded, the producer must examine the nutrient profile of the feeds carefully to ensure that desired production levels can be achieved and fish and shrimp health maintained. ? High inclusion (>50% fish meal protein replacement) of DJKM decreased the efficiency of conversion of feed to body mass. This could be explained partly by the increased mean feed intake which was possibly a reaction to the reduced protein retention, measured as protein efficiency ratio and protein productive value. No such effects were seen with the use of DJPI in common carp diets. ? Increased DJKM inclusion in diets caused a significant lowering of protein, lipid and energy digestibilities. No such effects were seen when DJPI was used in common carp diets. Effects on energy budget: ? Feeding DJKM and H-JPKM to common carp and Nile tilapia respectively did not change the major components of the energy budget (routine metabolic rate, heat released and metabolisable energy) compared to fish meal and soybean meal fed groups. These results revealed that dietary protein sources DJKM and H-JPKM can be efficiently utilized for growth by common carp and Nile tilapia respectively, as well as soybean meal and fish meal. Effects on expression of growth hormone and insulin-like growth factor-1 encoding genes ? As the level of DJKM inclusion increased in the common carp diet, growth rate decreased. The expression of Insulin-like growth factor-1 (IGF-1) in liver also decreased with increase of DJKM in the diet and that of the growth hormone in liver decreased. Effects on clinical health parameters and gut health: ? No mortality and unaffected haematological values suggested the fish were all in normal health. Alkaline phosphatase and ALT activities; urea nitrogen, bilirubin and creatinine concentration in blood were in the normal ranges which showed that there was no liver or kidney dysfunction. ? The measured plasma nutrient levels gave no indications of stress, but increasing the level of plant protein in the diet decreased plasma cholesterol. This may be related to high NSP content or reduced dietary intake of cholesterol. Decrease in muscle cholesterol level is also expected which could be considered good for human health. ? Histopathological evaluation of organs showed no damage to the stomach, intestine or liver of common carp or rainbow trout. Effects of Jatropha-phytate in Nile tilapia The defatted Jatropha kernel meal obtained after oil extraction is rich in protein (58−66%) and phytate (9 −11%). The phytate rich fraction was isolated from defatted kernel meal using organic solvents (acetone and carbon tetrachloride). It had 66% phytate and 22% crude protein and its inclusion in fish diets showed the following: ? Negative effects on growth performance, nutrient utilization and digestive physiology (nutrient digestibility and digestive enzymes). ? Adverse influences on biochemical entities such as metabolic enzymes (alkaline phosphatase and alanine transaminase) and electrolytes/metabolites. Salient changes include decreased red blood cell count and hematocrit content, decreased cholesterol and triglyceride concentrations in plasma and decreased blood glucose levels. The adverse effects observed may be due to the interaction of phytate with minerals and enzymes in the gastro intestinal tract, resulting in poor bioavailability of minerals and lower nutrient digestibility. The level of phytate used in the present study (1.5 and 3.0%) corresponds to 16.5% and 33.0% of DJKM in the fish diet. The DJKM at levels > 16.5% in the diet would exhibit adverse effects in Nile tilapia. Addition of phytase to the phytate containing diets would mitigate the adverse effects of at least up to 3% Jatropha phytate (or 33% DJKM) in the diet. Addition of phytase (1500 FTU/kg) in diets containing DJKM is recommended to maximize their utilization by Nile tilapia.