Suitability of selected raw materials and by-products in formulated feeds for Nile tilapia Oreochromis niloticus and African catfish Clarias gariepinus

Merged with duplicate record (10026.1/1967) on 03.01.2017 by CS (TIS)The current status of global aquaculture production was reviewed with a special emphasis on Africa and in particular Egypt. The main species of interest in this study were tilapia Oreochromis niloticus and African catfish Clarias gariepinus which are gaining popularity and are of considerable importance in the market of farmed fish in this continent and of economic relevance to Egypt and other Middle Eastern countries. Research was principally directed to establishing the suitability of specific feed ingredients and materials that could be included in balanced diets for both species. Various animal and plant by-products were selected to evaluate their nutritional value for either species. The experimental protocols, materials and methods and techniques employed are described for nutritional investigations with tropical freshwater fish. These included the various parameters assessed in the growth and digestibility studies relevant to the species in question. These include Specific Growth Rates (SGR), Feed Conversion Ratios (FCR), Protein Efficiency Ratio (PER) and Apparent Net Protein Utilisation (ANPU). An initial investigation to determine the coefficients of digestibility of protein, amino acids and energy was first undertaken using tilapia as the model warmwater fish species. This investigation was able to provide useful data and information as a prelude for successive growth trials with both tilapia and catfish. Fishmeal, soyabean meal, corn gluten meal, poultry by-products including feathermeal and blood meal were all tested at a variety of inclusion levels in successive trials. Apparent digestibility coefficients (ADC %) for tilapia fed diets containing 60% LT 94 fishmeal and 40% of each ingredient are reported. ADC of dry matter (DM) and protein (CP) and energy (E) for the reference fishmeal diet were 83.99 DM; 92.60 CP; and 93.31E respectively. For each test ingredient, these values were as follows; 1- PBM (56.99 DM; 69.30 CP & 73.47 E), 2- Feathermeal (54.09 DM, 45.53 CP & 49.11 E), 3- Blood meal (76.13 DM; 85.79 CP and 75.96 E), 4- Solvent extracted soyabean meal (85.83 DM; 93.46 CP & 82.16 E), 4- Full fat soyabean meal (75.86 DM; 86.99 CP & 74.84 E). The amino acid availability coefficients reflected the same trends as protein digestibility, and these varied from >87% on average for the essential amino acids in fishmeal, 83% for maize gluten and 85% for solvent extracted soyabean meal with an average of 63% for feathermeal and only 61% for poultry meat meal. The importance of plant protein sources and especially soyabean meal was the focus of a complete nutritional study with juvenile tilapia, The influence of full fat soyabean meal (FFSB) inclusion on growth performance, feed utilisation and the gastrointestinal digestive enzymes was also measured in this experiment. It was found that soyabean meal levels above 50% could reduce growth performance and adversely affect gut enzyme activities. Tilapia fed a series of diets with FFSB (58,63 and 63% + DLmethionine did not perform as well as the control group. SGR values ranged between 2.42 to 2.12, and ANPU between 39.41-34.46. Supplementation of the diet with methionine did not restore performance. Hepatic trypsin and amylase enzyme activity was affected with FFSB (from 12.64-1.43 Units and 4.99-2.76 Units respectively). No affects were detected on general proteolytic activity for stomach, intestine and liver. For studies with African catfish, it was first necessary to assess the different grades of fishmeal that could be employed in suitable reference diets for this species. A Poultry by-product meal (PBM) was further evaluated as a fishmeal replacement source (0- 100%) for this species. Catfish fed dry and wet diets of two types of fishmeal showed significant differences in growth performance. Catfish fed dry diets performed better than those receiving wet diets for both LT94 and white fishmeal sources. SGR were (2.80 and 2.75 dry) and (2.46 and 2.57 wet). FCR (0.97 and 0.80 dry) and (1.30,1.30 wet), ANPU (41.85,52.94 dry) and (31.43,30.9 wet) for LT94 and White fishmeal respectively. The PBM fed catfish showed significant differences in weight gain and feed utilisation. SGR was between 3.57 to 2.83, FCR between 1.61 to 2.25 and ANPU fell from 28.90 to 18.82 for groups' fed the control fishmeal diet towards the maximum level of PBM substitution. Histological examination of liver tissue showed alterations in hepatic morphology with respect to sinusoids and fat accumulation for catfish fed higher amounts of PBM. A restricted inclusion of up to 40% poultry by-product meal could therefore be suggested for practical diet formulations. Further investigations were undertaken to assess the potential for either maize gluten meal (MG) or soyabean meal as substitute protein sources for the African catfish Catfish fed higher inclusions of MG displayed SGR's ranging between 5.28 to 2.79, FCR between 0.81 to 1.53 and ANPU values from 52.33 to 24.99%. All lower performance data were obtained for 75% MG substitution of LT94 fishmeal protein. Further histological examination of liver tissue revealed alterations in hepatic structure associated with higher levels of MG. It was suggested that no more than 25% substitution of fishmeal with maize gluten meal is feasible under the present conditions. In a separate study, catfish fed diets containing different levels of FFSB (58,63 and 63% + DL-methionine) at the expense of fishmeal (LT94), showed significant differences in weight gain. SGR ranged between 3.11 to 2.78, FCR 0.82-0.83 and ANPU between 54.48 to 48.60. Also trypsin activities for intestine ranged between 2.75 to 1.71 Units, liver 1.37 to 1.05 Units and stomach 4.09 to 2.29 Units of activity for increasing levels of FFSB. Hepatic amylase was also reduced from 4.49 to 2.46 Units. General proteolytic activities however, did not show any significant differences between catfish fed different levels of FFSB for the stomach, intestine and liver. The conclusions from each of the nutritional trials were considered and comparisons between the response of tilapia and catfish were made. The advantages of plant based protein concentrates was stressed due to the problems currently existing for animal sources and the expense of fishmeal There were many similarities for the tilapia and catfish and it would seem that both fish species could greatly benefit from improved diet formulations that may meet with their nutritional requirements whilst minimising cost of production. A future strategy of research is presented that includes further work to identify more feed ingredients for potential use in these species

Experimental and numerical analysis of deformation and fracture of cortical bone tissue

Bones are the principal structural components of a skeleton; they provide the body with unique roles, such as its shape maintenance, protection of internal organs and transmission of muscle forces among body segments. Their structural integrity is vital for the quality of life. Unfortunately, bones can only sustain loads until a certain limit, beyond which it fails. Usually, the reasons for bone fracture are traumatic falls, sports injuries, and engagement in transport or industrial accidents. The stresses imposed on a bone in such activities can be far higher than those produced during normal daily activities and lead to fracture. Understanding deformation and fracture behaviours of bone is necessary for prevention and diagnosis of traumas. Even though, in principle, studying bone’s deformation and fracture behaviour is of immense benefit, it is not possible to engage volunteers in in-vivo investigations. Therefore, by developing adequate numerical models to predict and describe its deformation and fracture behaviours, a detailed study of reasons for, and ways to prevent or treat bone fracture could be implemented. Those models cannot be formulated without a set of experimental material data. To date, a full set of bone’s material data is not implemented in the material data-base of commercial finiteelement (FE) software. Additionally, no complete set of data for the same bone can be found in the literature. Hence, a set of cortical bone’s material data was experimentally measured, and then introduced into the finite-element software. A programme of experiments was conducted to characterise mechanical properties of the cortical bone tissue and to gain a basic understanding of the spatial variability of those properties and their link to the underlying microstructure. So, several types of experiments were performed in order to quantify mechanical properties of the studied bone tissue at macro- and microscales under quasi-static and dynamic loading regimes for different cortex positions called anterior, posterior, medial and lateral. Those experiments included: (1) uniaxial tension and creep tests to obtain its elastic, plastic and viscoelastic properties; (2) nanoindentation tests to characterise its microstructural elastic-plastic properties; (3) Izod tests to investigate its fracture properties under impact bending loading; (4) tensile-impact tests to characterise its impact strength and fracture force when exposed to a longitudinal loading regime. All the experiments were performed for different cortex positions and different directions (along the bone axis and perpendicular to it) when possible. Based on the results of those experiments, a number of finite-element models were developed in order to analyse its deformation and fracture using the extended finiteelement method (X-FEM) at different length scales and under various loading conditions. Those models included: (1) two-dimensional (2D) FE models to simulate its fracture and deformation at microscale level under quasi-static tensile loading. Additionally, the effect of the underlying microstructure on crack propagation paths was investigated; (2) 2D and three-dimensional (3D) FE models to simulate its fracture and deformation at macroscale level for the Izod impact test setup. In addition, the applicability of different constitutive material models was examined; (3) 3D FE models to simulate its fracture and deformation at macroscale level for tensile-impact loading conditions. The developed models provided high-quality results, and most importantly, they adequately reflected the experimental data. The main outcome of this thesis is a comprehensive experimental analysis and numerical simulations of the deformation and fracture of the cortical bone tissue at different length scales in response to quasi-static and dynamic loading. Recommendations on further research developments are also suggested

The geology and geochronology of Al Wahbah maar crater, Harrat Kishb, Saudi Arabia

Al Wahbah is a large (∼2.2 km diameter, ∼250 m deep) maar crater in the Harrat Kishb volcanic field in western Saudi Arabia. It cuts Proterozoic basement rocks and two Quaternary basanite lava flows, and is rimmed with an eroded tuff ring of debris from the phreatomagmatic explosion that generated the crater. A scoria cone on the northern wall of the crater was dissected by the explosion and exposes a dolerite plug that was intruded immediately prior to crater formation. The dolerite plug yields a <sup>40</sup>Ar/<sup>39</sup>Ar age of 1.147 ± 0.004 Ma. This is the best possible estimate of the time Al Wahbah crater formed. It is a few tens of thousand years younger than the age of the lower and upper basalt flows, 1.261 ± 0.021 Ma and 1.178 ± 0.007 Ma respectively. A dolerite dyke exposed within the basement in the wall of the crater is dated at 1.886 ± 0.008 Ma. This is the most precise age so far determined for the initiation of basaltic volcanism of Harrat Kishb, and confirms that it is significantly younger than the other post-rift volcanic provinces in the region. This study provides constrains the timing of humid climatic conditions in the region and suggests that the Quaternary basaltic volcanism that stretches the length of the western side of the Arabian peninsula may prove to be useful for establishing palaeoclimatic conditions

Dynamic properties of cortical bone tissue: impact tests and numerical study

Bone is the principal structural component of a skeleton: it assists the load-bearing framework of a living body. Structural integrity of this component is important; understanding of its mechanical behaviour up to failure is necessary for prevention and diagnostic of trauma. Bone fractures occur in both low-energy trauma, such as falls and sports injury, and high-energy trauma, such as car crash and cycling accidents. By developing adequate numerical models to predict and describe the deformation and fracture behaviour up to fracture of a cortical bone tissue, a detailed study of reasons for, and ways to prevent or treatment methods of, bone fracture could be implemented. This study deals with both experimental analysis and numerical simulations of this tissue and its response to impact dynamic loading. Two areas are covered: Izod tests for quantifying a bone’s behaviour under impact loading, and a 3D finite-element model simulating these tests. In the first part, properties of cortical bone tissue were investigated under impact loading condition. In the second part, a 3D numerical model for the Izod test was developed using the Abaqus/Explicit finite-element software. Bone has time-dependent properties – viscoelastic – that were assigned to the specimen to simulate the short term event, impact. The developed numerical model was capable of capturing the behaviour of the hammer-specimen interaction correctly. A good agreement between the experimental and numerical data was found

Numerical modelling of impact fracture of cortical bone tissue using X-FEM

A cortical bone tissue is susceptible to fracture that can be caused by events, such as traumatic falls, sports injuries and traffic accidents. A proper treatment of bones and prevention of their fracture can be supported by in-depth understanding of deformation and fracture behaviour of this tissue in such dynamic events. Parameters such as damage initiation under impact, damage progression and impact strength can help to achieve this goal. In this paper, Extended Finite-Element Method (X-FEM) implemented into the commercial finite-element software Abaqus is used to simulate the actual crack initiation and growth in a cantilever beam of cortical bone exposed to quasi-static and impact loading using the Izod loading scheme. Izod tests were performed on notched bone specimens of bovine femur to measure its impact strength and to validate simulations. The simulation results show a good agreement with the experimental data

Plastic behaviour of microstructural constituents of cortical bone tissue: a nanoindentation study

A mechanical behaviour of bone tissues is defined by mechanical properties of its microstructural constituents. Also, those properties are important as an input for finiteelement models of cortical bone to simulate its deformation and fracture behaviours at the microstructural level. The aim of this study was to investigate a post-yield behaviour of osteonal cortical bone’s microstructural constituents at different loading rates, maximum load levels and dwell times; nanoindentation with a spherical-diamond-tip indenter was employed to determine it. The nanoindentation results revealed significant difference in stiffness values of cortical bone’s microstructural features − interstitial matrix and osteons. Similarly, interstitial matrix exhibited a stiffer post-yield behaviour compared to that of osteons that reflects the relationship between the post-yield behaviour and collagen maturity. In addition, both osteons and interstitial matrix demonstrated a time-dependent behaviour. However, in order to assess elastic-plastic behaviour accurately, an effect of viscosity on nanoindentation results was reduced by using a time-delay method

Editorial: Molecular and multi-omic approaches in understanding cancer biology and anticancer therapies: current perspectives and new challenges

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Toxico-histological Effects of Sublethal Concentrations of Lead Nitrate on the Gills of the African Catfish, Clarias gariepinus

170-175This study aimed to investigate the effects of subleathal lead doses on the histological architecture of gills in the freshwater African catfish, Clarias gariepinus. Results revealed three stages of changes after exposure to three doses of lead nitrate. The changes were mild in fish exposed to 16.12 mg/L of Pb (NO3)2 (stage I 20% of LC50) and severe in case of 40% of LC50 (stage II, 32.24 mg/L) and 60% of LC50 (stage III 48.37% mg/L) in comparison to control. The histological examination revealed normal architecture of gills in control fish. Normal gills were characterized with primary gill lamellae with a central hyaline cartilage. However, three-stage changes were observed after exposure to the three doses of lead nitrate. In stage I, a cartilaginous matrix appeared along with loosening of the epithelial lining of the cartilaginous core and abundant vascular spaces were observed on the secondary gill lamellae. An extra cartilaginous matrix, loosening of the epithelial lining of the cartilaginous core, de-shaped gill lamellae, and degeneration of the secondary gill lamellae were noted in stage II. Lesions in the gill pattern in stage III were represented by shortening of the tips of secondary gill lamellae, damaged gill lamellae, a cartilaginous matrix, and hyperplasia. This indicated that lead exposure resulted in severe histopathological changes in the gills in a dose-dependent manner

3-Acetyl-5-phenyl-1-p-tolyl-1H-pyrazole-4-carbonitrile

In the title pyrazole derivative, C19H15N3O, the central pyrazole ring makes dihedral angles of 42.71 (9) and 61.34 (9)°, respectively, with the phenyl and p-tolyl rings. The dihedral angle between the phenyl and p-tolyl rings is 58.22 (9)°. The 3-acetyl-1H-pyrazole-4-carbonitrile unit is essentially planar, with an r.m.s. deviation of 0.0295 (1) Å for the ten non-H atoms