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The objective of this work was to assess the acceptance of live and inert food by Macrobrachium tenellum during the early larval stages. The larvae were obtained by collecting wild ovigerous females in the Ameca River in the State of Jalisco, Mexico. Eight treatments (diets) were used to feed the larvae: D1, control (fasting); D2, micro-pulverized food (Purina®); D3, living, newly hatched nauplii of Artemia franciscana (INVE®, Salt Lake City, Utah, USA); D4, commercial paste containing microalgae (Instant Algae Rotifer Diet®); D5, water extracted from a biofloc system; D6, cooked egg yolk; D7, newly hatched and frozen nauplii of A. franciscana (INVE®, Salt Lake City, Utah, USA); D8, nutritional supplement for shrimp larvae (Epifeed LH1®). Treatments D2, D5, D6 and D8 showed traces of food in the digestive system. The larvae did not consume D3 and D7 treatments. The diets that had more acceptance were micro-pulverized food, a nutritional supplement for shrimp larvae Epifeed® LH1, cooked egg yolk, and biofloc water. [ABSTRACT FROM AUTHOR]

In the present study, the potential of three isolated microalgae strains from Bahía de La Paz, Baja California Sur, Mexico and identified as Schizochytrium sp. (Inner key: LPU-1), Chaetoceros sp. (LPU-2), and Chaetoceros sp. (LPU-3) for the cultivation of the rotifer Brachionus plicatilis was tested. The effects of isolated strains on the population growth and nutritional content (proteins, lipids, carbohydrates, and fatty acid composition) of B. plicatilis were evaluated. The feeding essay of B. plicatilis was carried out at 32 ± 2°C. Treatments were established using a monoalgal and dialgal diet: Schizochytrium sp. (LPU-1), Schizochytrium sp. (LPU-1)/Chaetoceros sp. (LPU-2), Chaetoceros sp. (LPU-2), Chaetoceros sp. (LPU-3), Chaetoceros sp. (LPU-2)/Chaetoceros sp. (LPU-3). The results show that the rotifers population growth ratio was higher with Schizochytrium sp. (LPU-1) 0.88 ± 0.43, Chaetoceros sp. (LPU-3), 0.87 ± 0.37, and from both 0.87 ± 0.40. The results show that the native microalgae of a North Pacific area mixed are an excellent source of nutrients for the growth and enhancement of the nutritional value of the rotifers, which can be used in the future to feed the larvae of marine fish more nutritionally and economically. [ABSTRACT FROM AUTHOR]

Arthrospira ( Spirulina) is a microalgae that has a unique set of biological characteristics which are very useful for a broad range of applications. Based on its worldwide requirements, this investigation was conducted to collect, isolate and identify the local Arthrospira strains in the central and western part of Mexico. We have successfully collected, isolated and identified (morphologically as well as molecularly) three Arthrospira strains from different regions in Mexico. Morphological studies were conducted by analyzing the size and shape of the helix, the spiral pattern, cell length and width with the help of light microscopy and for molecular analysis, the 16S rRNA and internally transcribed spacer (ITS, 16S-23 rRNA) gene partial sequence were used followed by phylogenetic analysis. The three species were completely different in their filament size and width whereas their ITS sequences were the same in size and more than 87 % similar in nucleotide sequence. The resulted morphological and phylogenetic analysis concluded that the three stains were identified as Arthrospira platensis. Inspite of their morphological variations and differences they were grouped genetically into one cluster along with the A. platensis of reported strains of Gene Bank database (NCBI). One of the isolated strains NPS-0, is probably the biggest Arthrospira strains ever reported and can be suitable for industrial scale biomass and protein production. [ABSTRACT FROM AUTHOR]

Abstract: Examples of two closed lagoons with extensive growth of Recent microbialites showing variable surface morphology and internal structure are found on Isla Angel de la Guarda in the Gulf of California. Comparable lagoonal microbialites also occur ashore from Ensenada El Quemado on the adjacent peninsular mainland of Baja California. The perimeters of all three lagoons feature crusted structures indicative of thrombolites with a knobby surface morphology 2cm to 3cm in relief and internal clotting without any sign of laminations. Outward from this zone, thrombolitic construction thins to merge with a white calcified crust below which a soft substratum of dark organic material 4cm to 6cm in thickness is concealed. The substratum is laminated and heavily mucilaginous, as observed along the edges of extensive shrinkage cracks in the overlying crust. The thrombolitic crust is anchored to the shore, while the thinner crust and associated stromatolitic mats float on the surface of the lagoons. Laboratory cultures of the dark organic material yielded the solitary cyanobacterium Chroococcidiopsis as the predominant taxon interspersed with filamentous forms. In decreasing order of abundance, other morphotypes present include Phormidium, Oscillatoria, Geitlerinema, Chroococus, and probably Spirulina. The larger of the two island lagoons follows an east–west azimuth and covers 0.225km2, while the smaller lagoon has a roughly north–south axis and covers only 0.023km2. The salinity of water in the smaller lagoon was measured as148ppt. Pliocene strata along the edge of the smaller modern lagoon include siltstone bearing calcified platelets suggestive of a microbial origin. Dry lagoons abandoned during the later Quaternary occur inland at higher elevations on the island, but retain no fossils except for sporadic white crusts cemented on cobbles around distinct margins. Raised Quaternary lagoons parallel to the big lagoon on Isla Angel de la Guarda are partly obscured by flood damage, but still easily mapped from aerial photos. These features suggest that Isla Angel de la Guarda experienced Quaternary uplift similar in scale to many other gulf islands on which marine terraces are preserved. Closed lagoons around the Gulf of California represent a stable oligotrophic ecosystem affected by extreme aridity and hypersalinity, punctuated episodically by the injection of floodwater from tropical storms. The taxonomic and geographic ranges of microbial communities throughout the larger region remain to be explored. [Copyright &y& Elsevier]

Humans are no strangers to the consumption of microalgae as already in the sixteenth century Spirulina was harvested from Lake Texcoco and consumed in markets in Tenochtitlan (today Mexico City). Nowadays, microalgae are being incorporated into many food formulations. Most of these use microalgae as a marketing strategy or as a colouring agent. However, Spirulina (and compounds derived thereof) show potential for being used as ingredients in the development of novel functional foods, which are one of the top trends in the food industry. Several human intervention studies demonstrated the potential of Spirulina for being used in the prevention or treatment of disorders related to metabolic syndrome. The aim of the current paper was to review current and potential applications of this microalga in the food and functional food industries. Health benefits associated with consuming Spirulina and/or some of the most important compounds derived from Spirulina were also discussed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Spirulina maxima is a filamentous cyanobacterium used as food supplement because of its high nutrient contents. It has been experimentally proven, in vivo and in vitro that posses several pharmacological properties. The purpose of this study was to evaluate the effects of Spirulina maxima orally supplied (4.5 g/day, for 6 weeks) to a sample of 36 subjects (16 men and 20 women, with ages between 18-65 years) on serum lipids, glucose, aminotransferases and on blood pressure. The volunteers did not modify their dietary habits or lifestyle during the whole experimental period. From each subject, a sample of blood was drawn in fasting state of 12 hours to determi the plasma concentrations of glucose, triacylglycerols (TAG), total cholesterol (TC), cholesterol associated to high density lipoprotein (HDL-C) and aspartate aminotransferase (AST). Anthropometric measurements including systolic (SYST-P) and diastolic (DIAST-P) blood pressure, height, weight and Body Mass Index (BMI) were also recorded., Results: Comparing initial and final data, the results showed that there were no significant changes in the values of glucose and AST, but significant differences in TAG, TC, and HDL-C, were observed: TAG 233.7 +/- 177.8 vs. 167.7 +/- 100.7 mg/dL (p < 0.001), TC 181.7 +/- 37.5 vs. 163.5 +/- 34.4 mg/dL (p < 0.001), C-HDL 43.5 +/- 14.4 vs. 50 +/- 18.8 mg/dL (p < 0.01). The univariated analysis showed that the changes in the HDL-C and TC concentrations were dependent on TAG concentration (p = 0.247 and p = 0.108, respectively); nevertheless the calculated values for cholesterol associated to low density lipoprotein (LDL-C) were significantly reduced by the Spirulina maxima treatment but independently of the TAG changes. In addition, significant differences were found comparing initial and final SYST-P and DIAST-P blood pressure in both male and female: SYST-P male 121 +/- 9 vs. 111 +/- 8 mm Hg (p < 0.01), DIAST-P male 85 +/- 6.5 vs. 77 +/- 9 mm Hg (p < 0.01); SYST-P female 120 +/- 9.5 vs. 109 +/- 11 mm Hg (p < 0.002), DIAST-P female 85 +/- 11 vs. 79 +/- 7.5 mm Hg (p < 0.03)., Conclusion: The Spirulina maxima showed a hypolipemic effect, especially on the TAG and the LDL-C concentrations but indirectly on TC and HDL-C values. It also reduces systolic and diastolic blood pressure.

In this paper is presented the percentage of fatty acids composition of three Artemia franciscana Mexican populations of epicontinentals waters; two are from natural environments (Coahuila and San Luis Potosf) and one (Texcoco) is a culture fed with Spirulina. Determination of fatty acids composition in each population, was performed by extraction of total lipid by the soxhlet method and the fatty acids methyl esters were determined by gas chromatography. The results show that Artemia of Texcoco contains the six fatty acids recommended for the culture of fish and crustaceans (16:0; 16:1; 18:1; 18:2w6; 18:3w3 and 20:5w3); Artemia from San Luis Potosi showed the poorest content in these acids and Artemia from Coahuila, although it showed a wide profile, it lacks the linolenic acid. When comparing results among the three populations with ecological data that have been published, it can be pointed out that the environment is decisive for this crustacean; Artemia from Texcoco fed with Spirulina showed the largest variety of fatty acids; the other two populations are wild, and lives in different habitats, Artemia of Coahuila is found in waters that are rich in sulfates and Artemia of San Luis Potosf lives in evaporation saltern ponds, built with stone blocks and therefore with scarce phytoplankton growth. Both Artemia populations showed deficiencies in essential fatty acids, mainly the last one.