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An 8-week feeding trial was conducted in a warmwater recirculation system at 27 + 0.2 C to evaluate the nutritive value of dhaincha (Sesbania aculeata) seed meal as a possible fish meal substitute in the diet of tilapia. Five isonitrogenous and isoenergetic diets were formulated to contain 32% crude protein and 18.4 kJ g À1 gross energy. Sesbania seed meal was included in diets at various levels [0%, 9.7%, 19.4%, 29.1% and 38.8% for diets 1 (control), 2, 3, 4 and 5, respectively, which correspond to 0%, 10%, 20%, 30% and 40% of dietary crude protein]. Each treatment had two replicates, eight fish per replicate, with mean initial weight of 7.06 + 0.03 g. Fish were fed 20 g kg À1 metabolic body weight daily. On the basis of the observed growth rate, feed conversion ratio, protein efficiency ratio, apparent net protein utilization and energy retention, diets 1 (control) and 2 (containing 9.7% Sesbania meal) were similar and significantly (P , 0.05) better than the other dietary groups. Fish fed diets 3, 4 and 5 containing higher levels of Sesbania meal showed significantly reduced growth performance compared with those fed diets 1 and 2. Fish fed diets 3, 4 and 5 had significantly lower faecal dry matter (DM) content, apparent crude protein, lipid and energy digestibility and reduced levels of cholesterol compared with the control and diet 2.Fish fed diets containing higher levels (.9.7%) of Sesbania meal had significantly higher whole-body moisture, lower lipid and gross energy content. The lower growth performance of fish fed diets containing higher levels of Sesbania meal is thought to result from the presence of tannins, saponin and the non-starch polysaccharide content of the seed. The results of this study showed that inclusion of up to 9.7% untreated Sesbania seed meal (10% of the dietary protein) in the diet did not affect the growth performance and nutrient utilization in tilapia.

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This study investigated the effects of varying dietary levels of decosahexaenoic acid (DHA) on growth performance, proximate composition and whole body fatty acid profiles of juvenile silver pomfret, Pampus argenteus. Triplicate groups of fish (30.55 ± 0.08 g) were fed diets containing 5.2%, 9.31% and 13.38% DHA (% of total fatty acids) or 0.85%, 1.52% and 2.18% DHA on dry diet weight for diets 1, 2 and 3 respectively. Survival was not affected by dietary DHA levels. The growth performance and feed utilization parameters of fish fed diets 2 and 3 were significantly (P < 0.05) higher than those fed diet 1, although these parameters in diets 2 and 3 did not differ significantly (P > 0.05). Whole body lipid and fatty acid profiles were influenced by dietary DHA levels. Significantly higher n-3 fatty acids particularly DHA, DHA:EPA(eicosapentaenoic acid) ratios and n-3:n-6 ratios were observed in fish fed diets 2 and 3 compared to those fed diet 1. Better growth performance and higher whole body DHA:EPA (2.31, 2.29) ratios and n-3:n-6 ratios (2.17, 2.12) observed in fish fed diets 2 and 3, respectively, suggests that silver pomfret juveniles have a higher requirement for n-3 fatty acids, notably DHA for optimum growth and survival.

Abstract-In this paper, a novel planar array antenna for multi-band linear polarization discrimination is proposed. The proposed array antenna consists of 12 patch elements and a double-balanced multiplier. A slot-ring and four diodes used in the multiplier also act as an antenna and amplitude detector, respectively. Furthermore, slot lines which are parts of feeding circuits also act as slot antennas. The Both-sided MIC technology is effectively employed to realize the feeding circuit which eliminates the extra impedance matching circuit. The array antenna is realized in a very simple and compact structure as all the antenna elements, feeding circuit and the multiplier/amplitude detector are arranged on both sides of a substrate. The proposed array antenna can discriminate ±45 • linear polarization in three frequency bands. The ability of the proposed array antenna to discriminate orthogonal linear polarization is successfully confirmed in C and X band by the experimental investigation.

Abstract-In this paper, a technical concept and design of circular polarization detection patch array antenna using a double-balanced RF multiplier is proposed. The microwave integration technology is effectively employed to realize the proposed array antenna. The double-balanced RF multiplier is integrated with an orthogonal planar array antenna. The array antenna which consists of 12 patch elements and the RF multiplier is realized by embedding four zero bias Schottky barrier diodes on a slot-ring. The Both-sided MIC technology is successfully employed to realize the array antenna. The array antenna is realized in a very simple and compact structure as all the antenna elements, feeding circuit and the RF multiplier are integrated on both sides of a dielectric substrate. The ability of the proposed array antenna to detect the orthogonal circular polarization (LHCP and RHCP) is successfully confirmed by the experimental investigation.

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