• Journal of Microbiology and Biotechnology
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• v.21 no.7
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• pp.697-702
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• 2011

A strain of the cyanobacterium Arthrospira was isolated from Lake Chahannaoer in northern China and was characterized according to microscopic morphology, photosynthetic oxygen-evolving activity, growth rate, and nutritional profile. Compared with thermophilic Arthrospira species occurring naturally in tropical and subtropical lakes, this isolate is mesophilic and grows optimally at ${\sim}20^{\circ}C$. The total protein, fatty acid, phycocyanin, carotenoid, and chlorophyll a contents were 67.6, 6.1, 4.32, 0.29, and 0.76 grams per 100 grams of dry weight, respectively. The strain is rich in polyunsaturated fatty acids (PUFAs). An essential omega-3 fatty acid, docosahexaenoic acid (DHA), was detected, and ${\gamma}$-linolenic acid (GLA) and DHA accounted for 28.3% of the total fatty acid content. These features of this newly isolated strain make it potentially useful in commercial mass culture in local areas or as a biofuel feedstock. It is also an alternative resource for studying the metabolic PUFA pathways and mechanisms of cold stress tolerance in cyanobacteria.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.206-215
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• 2009

This experiment was carried out to evaluate performance and carcass characteristics of 40 crossbred young bulls ($Zebu{\times}European$) finished in a feedlot under two roughage sources (Bermuda grass hay or sorghum silage) with or without the addition of yeast (Saccharomyces cerevisae). The bulls were 20 months old, their initial average weight was 356 kg and they were allocated into four groups of ten animals. The experimental diets were Bermuda grass, Bermuda grass+yeast, sorghum silage and sorghum silage +yeast. Animal performance and carcass characteristics were not influenced by roughage source or yeast addition. The average daily weight gain was 1.50 kg, dry matter intake (DMI) was 11.1 kg/d, DMI as percentage of liveweight was 2.60% and feed dry matter conversion was 7.70. The mean dressing percentage was 52.0% and hot carcass weight was 268 kg. Carcass conformation was classified between good-minus to good. Carcass length (137 cm), leg length (72.9 cm) and cushion thickness (26.6 cm) were not influenced by treatments. The average fat thickness was 3.80 mm and the Longissimus muscle area was 66.9 $cm^{2}$. The classification of color, texture and marbling were slightly dark red to red, fine and slight-minus to light-typical, respectively. The mean percentage of bone, muscle and fat in the carcass was 15.5%, 62.3% and 22.5%, respectively. Yeast addition increased ${\gamma}$-linolenic fatty acid (0.15 vs. 0.11%) deposition. Bermuda grass hay increased deposition of ${\alpha}$-linolenic (0.49 vs. 0.41%), arachidonic (2.30 vs. 1.57%), eicosapentaenoic (0.41 vs. 0.29%), docosapentaenoic (0.80 vs. 0.62%), docosahexaenoic (0.11 vs. 0.06%) and n-3 fatty acids, and reduced n-6: n-3 ratio in meat, when compared to sorghum silage treatments. The treatments had no effect on saturated fatty acids (49.5%), polyunsaturated fatty acids (11.8%), n-6 fatty acids (9.87%), n-3 (1.61%) and PUFA:SFA ratio (0.24). Monounsaturated fatty acid levels were higher on sorghum silage (40.7 vs. 37.7%). The addition of yeast caused higher n-6: n-3 ratio (7.28 vs. 5.70) than treatments without yeast.