Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Background. Different methods are currently used for the prevention and control of diseases in aquaculture. Prophylaxis with immunostimulants from microscopic fungi provides protection against diseases and increases resistance to parasites. In this context, Basidiomycota fungi could have high potential for use in aquaculture because they contain different compounds, such as fungal proteins, polysaccharides, terpenoids, vitamins, and minerals, which could work as immunostimulants. Goals. Collect and disseminate the information on species of macroscopic fungi that have been used as immunostimulants in the farming of teleost fish and the fungi that have not been tested in fish but have shown positive results in other organisms. Methods. We gather, discuss and compare the experimental, scientific and theoretical literature related to the immunostimulant effect of macroscopic fungi in the cultivation of teleosts, as well as fungi whose stimulating effect has been positive in other organisms. Results. We evaluated more than 50 species of fungi with immunostimulating properties. Nevertheless, in recent years, the effects of only eight species of macromycetes, belonging to the genera Ganoderma, Inonotus, Lentinula, Pleurotus, and Trametes, have been evaluated in 17 published papers regarding the immune response of nine species of fish. Seven of these papers are about isolated glucans, six about crude and alcoholic extracts, two about pulverized basidiomata, and one about a mushroom fermented by-product. Conclusions. Due to the limited information on the immunostimulating effect of macromycetes on fish, more research is needed regarding other fungi species with immunostimulant properties, the correct determination of fungi species, their culture, and in vivo and in vitro tests that confirm their immune system effects on the model organism and target organism.  

Background. Most growth analyses of Yellowtail Snapper neglect consideration of model and parameter uncertainty. Goals. In this paper, we explore model uncertainty using three models (von Bertalanffy, logistic, and Gompertz) as well as the Akaike criterion for model selection. We also estimate growth parameters and its uncertainty using the maximum likelihood estimation approach (under different assumptions of error variance) and Bayesian methods. Methods. Models were fitted to length-at-age data from organisms caught in Antón Lizardo, Veracruz. Regarding the Bayesian methods, a prior distribution for the asymptotic length was built based on data gathered from literature. We used Monte Carlo Markov Chains (MCMC) methods to fit the logistic model. Results. The Akaike criterion results suggest that the logistic model provided the best fit for the observed data (lowest AIC = 31.4). Parameter estimates included asymptotic length (L? = 64.9 ± 5.43), growth rate (K = 0.49 ± 0.07), and age at the curve inflection point (I = 3.28 ± 0.42). Regarding the Bayesian analysis, MCMC simulations suggest that the most probable value for the asymptotic length was 64.3 cm with an interval of 95% probability (58.7,70.1). The most probable value for the growth rate was 0.48 with an interval of 95% probability (0.42, 0.55). Last, the most probable value for the age at the curve inflection point was 1.7 years with a range of 95% probability (1.31, 2.16). Conclusions. The maximum likelihood estimation (MLE) and the Bayesian framework should be considered basic statistical techniques in the evaluation of individual growth of the species of interest, as they provide a robust analysis of available information of the species and the opportunity to incorporate such analysis to sustainable management practices.  

Background. Teeth can change significantly in shape and size depending on their position in the jaw, age and sex of the organism. Sometimes due to the loss of these teeth, an incomplete description of the dental morphology exists for several batoid species, which makes it difficult to evaluate intraspecific and interspecific differences. Goals. Describe the differences in tooth morphology as well as the arrangement of teeth in adults of two species of batoids (Urotrygon nana and U. rogersi) distributed over soft bottoms of the continental shelf of the Mexican tropical Pacific. Methods. After collecting the jaws of ten adult individuals of U. nana and U. rogersi we counted the number of rows and series of the first functional row, and described the shape of the cartilage and teeth. In addition, we identified the type of heterodonty. Results. Similarities between the cartilage and teeth of both species were observed. In both sexes of U. nana monognatic heterodonty was observed, with three dental morphotypes in Palatocuadrado and two in Meckel’s cartilage. U. rogersi has sexual heterodonty with just one morph. Conclusions. We believe it is necessary to expand the number of samples (taking into account the different stages of life), and generate additional ethological studies that provide information on the reproductive behavior of the species.  

Background. One of the promising directions in agriculture is the rational use of biologically active substances or plant growth stimulators obtained from local raw materials. In Mexico, seaweed can be considered a cheap, abundant, and accessible local resource along the Mexican coast. It represents great potential for eventual commercial exploitation as a source of plant growth promoters. Previous reports have emphasized the importance of seaweed extracts and their utilization with significant results to improve seed germination, seedling development, growth, and yield of plants, increasing crop productivity. The main effects should be in the first stages of plant ontogenesis, beginning with seed germination and seedling growth. The effects of seaweed liquid extracts in the early stages of plant growth are on root-system growth, providing a signal of the value and quality of the future crop. Therefore, the search for the most effective extracts that stimulate plant development is considered a priority. Goals. Show an overview of the application of seaweed extracts in Mexican agriculture. Results. Information is provided on the administration and regulation for the harvest of marine algae, and the research carried out in Mexico. The management and harvest regulations for the algae, including seaweed liquid extract composition, biological efficacy of promoting plant growth, as well as elicitors of disease defense caused by pathogens. Conclusions. Seaweeds from Mexico have enough potential for the isolation of biologically active compounds that could increase agriculture productivity. This research is essential for the future of Mexican agriculture, to develop effective strategies to use seaweed extracts.  

Background: The term fecundity in abalone is defined according to an estimate of its absolute fecundity, which is the number of mature oocytes present in the gonad, or as potential fecundity, i.e., the total number of oocytes present in the gonad. In Mexico, few studies have estimated the fecundity of mollusks and these have been performed on gonads in different phases of gonadal development, obtaining values that are very different or overestimated, for example, values ranging from 80000 to 22 million oocytes in a gonad. Goals: Estimate the fecundity of Haliotis fulgens (blue abalone) and Haliotis corrugata (yellow abalone), using ma­ture gonads and a particle counter (Multisizer 3) to count only mature oocytes. Methods: Each month from October 2011 to February 2013, 30 adult organisms of each species were collected in two localities of Baja California Sur, Mexico (La Bocana and Bahía Tortugas). A histological analysis identified those that were mature females. To obtain the number of eggs per gram, triplicate oocyte counts were performed in a coulter counter Multisizer 3, in a solution of 4 g wet weight of mature oocytes diluted to 50 mL of filtered seawater (μm). Absolute fecundity was calculated by multiplying the total weight of the gonad by the number of mature oocytes present in one gram of oocytes. Results: The fecundity in La Bocana was found to be 2x106 eggs in H. corrugata and H. fulgens, while in Bahia Tortugas it was 4x106 eggs in H. fulgens. Conclusions: This study suggests that estimating absolute fecundity in species with partial spawning, such as H. fulgens and H. corrugata, should be per­formed on all females regardless of the degree of gonadal development. However, only mature oocytes should be considered as an indicator of absolute fecundity. Therefore, the use of an apparatus that counts and measures mature oocytes, such as a particle counter, facilitates and guarantees a good estimate of fecundity.

Background: The virus Panulirus argus Virus 1 (PAV1) causes a detrimental effect on the spiny lobster Panulirus argus (Latreille, 1804). It produces in their natural habitats a chronic-degenerative infection until producing death.  Mexico is one of the main exporters of lobster´s tails. Thus, it is important to assess the presence of PaV1 in products intended for overseas commercialization. Goal: The objective of this study was to determine the prevalence of PaV1 in lobsters from two main fishing zones in the state of Yucatan. Methods: 496 lobsters P. argus were collected from two fishing zones (327 from the Orient zone: Rio Lagartos and 169 from the Central zone: Progreso) from the Yucatan Península. A PCR specially designed to amplify a 499 bp region from the genomic DNA of PaV1 was used to screen this virus. A portion of 20 mg was collected from each organism, and a PCR that amplifies a 499 bp fragment from genomic DNA of PaV1 was used for the screening. The ?2 test and logistic regression were used to determine the differences between these variables. Conclusions: This is the first report of the virus Panulirus argus virus 1 (PaV1) in frozen tails of sub-adults and adults spiny lobsters Panulirus argus collected from the northern coast of the Yucatán Peninsula intended for commercialization and exportation. The prevalence of PaV1 was higher in the Orient-Rio Lagartos zone (4.62%) than in the Central-Progreso zone (1.52%) (?2; p <0.05). PaV1 could represent a high risk for mechanical dispersion of this pathogen into other countries free of PaV1 infection.  

Background. The diversity of irregular echinoids along the Pacific coast of Mexico is still not well known. This group has developed a selection of a restricted substrate; in addition, they are morphologically adapted to bury themselves in sediment that makes them difficult to locate in the field. Goals. To prepare a checklist of species of irregular echinoids including new records of the Cassiduloida, Clypeasteroida, Holasteroida, and Spatangoida orders found along the coasts of Nayarit, Jalisco, and Colima. Methods. Organisms were collected through various sampling operations undertaken between December 2013 and August 2017, in subtidal zones with Scuba diving gear (up to 10 m) and in sandy beaches using manual collection. In addition, we carried out a review of bibliographic sources and scientific collections. Results. Eighteen species from nine families and four orders of irregular urchins were registered for the coasts of Nayarit, Jalisco, and Colima. For Nayarit there are nine species and the species Encope micropora was registered for the first time in Playa Novillero. Ten species were recorded in Jalisco and 14 species in Colima, which for both states established new records for the species Rhyncholampas pacificus, Agassizia scrobiculata, Brissus obesus, Metalia spatagus, and Plagiobrissus pacificus. Conclusions. The literature review, complemented with field sampling, helped increase the diversity of species of irregular sea urchins in the central Mexican Pacific region. Determining the diversity of these species will make it possible to propose future studies on their ecology, in order to specify their ecological role in coastal ecosystems and their potential use for the conservation of marine communities.  

Background. The main function of extender solutions for trout semen is to preserve viability while keeping the sperm motility inactivated. The longer the sperm remain viable and inactivated the better, so that later they can be intentionally activated when the sperm must travel to reach the egg micropyle for fertilization. In rainbow trout (Oncorhynchus mykiss), considerable advances have been made concerning the production of sperm extenders, quality control protocols, and the handling of gametes. However, the protocols for using an extender can differ considerably, especially regarding the extender composition. Additionally, the precise impact of pH on sperm motility, and its effect in the design and selection of a sperm extender remain unclear. Goals. The aim of this study was to determine the effect of pH on rainbow trout sperm motility and activation during storage at 5 °C and using 5 different extenders. Methods. Three simple composition sperm extenders (306, 512, and Mounib) and two complex composition sperm extenders (Erdahl & Graham, and Hank's) were tested at different pHs (7, 7.2, 7.4, 7.6, 7.8, 8.0, and 8.2), as well as 3 activation solutions (DIA 532, saline solution, and pond water). Results. The extenders showed a high buffer capacity. The highest percentages of motility were obtained with DIA 532. Extenders 306, 512, and Hanks exhibited a positive relationship between pH and % motility. Erdahl & Graham and Mounib extender did not induce motility in rainbow trout sperm at different pHs. Conclusions. A positive relationship was found between the pH and motility of trout sperm, as well as a negative effect regarding the activation solution DIA 532 with the 306, 512, and Hanks extenders.

 Background: Lectins act in plants and animals as recognition units against invasive pathogens, participate by activating the immune system, and function as recognition mediators of immune response in invertebra­tes. Few studies have evaluated the effect of immunostimulants on the activation of lectins in crustaceans. Goals: To evaluate the lectin concentration in juvenile shrimp treated with commercial and microbial im­munostimulants. Methods: Five treatments were added directly to the culture tanks every third day during 12 days: 1) laminarin (0.5 mg ml-1); 2) mix 1 (Bacillus tequilensis and B. licheniformis; 2x106 CFU ml-1, 1:1 proportion); 3) mix 2 (B. endophyticus, strain YC3-B and strain C2-2; 2x106 CFU ml-1, proportion 1:1); 4) Debaryomyces hansenii (1x106 CFU ml-1); 5) control (without immunostimulants). At day 12, after the last treatments were added, samples of hemolymph were extracted from shrimp at 24, 48, and 72 h to determine lectin concentration by the ELISA method, using monoclonal antibodies against Macrobrachium rosenbergii lectin (MrL). Results: Significant differences (p <0.05) in the lectin concentration were found in shrimp groups treated with laminarin at 24 h after the last exposure to the treatment, followed by mix 1 and mix 2 at 72 h after exposure to the treatments. At 48 h, treatments did not register significant differences (p >0.05) when compared to the control groups. Shrimp exposed to D. hansenii did not show significant increase in lectin concentration compared to the control groups. Conclusions: This study showed that lectin concen­tration may be increased in plasma of juvenile shrimp and used as a bioindicator tool of immunostimulation.

Background. Oncorhynchus mykiss is a species that is widely cultivated in the world with high economic value. For this reason, it is essential to optimize its growth and reproduction for aquaculture. Goals. Evaluate the growth and sperm quality of rainbow trout during the reproductive season. Methods. We conducted research at the "El Zarco" Aquaculture Center in the state of Mexico, with 32 sexually mature three-year-old males. Once a month, we recorded total length, height, thickness (cm), and weight (g) during July-February, and calculated weight gain (WG), absolute growth rate (AGR), and instantaneous growth rate (IGR). Semen samples were obtained during (August-February). In order to evaluate the spermatic quality, we measured volume, color, consistency, concentration, pH, and mobility. Results. The highest AGR, WG, and IGR in terms of length and weight were obtained from July-August, i.e., a month prior to the reproductive period; from August-February the AGR was 1.13 cm, WG was 0.01 g, and there was an average IGR of 0.0321 ± 0.0522 cm and 0.0932 ± 0.2223 g. Differences (p <0.05) in length and weight were found between July and the months of the reproductive period. There was a pattern of semen production: It increased from August to October and then decreased until February, with significant differences (p <0.05). Usually, white semen and milky consistency were found. The highest sperm concentration occurred in September (8.17 ± 2.06 x 109 mL-1) and decreased until February, with significant differences (p <0.05) between months. The pH was alkaline with an average value of 8.07 ± 0.31. Mobility increased from August to December and decreased from January to February, with significant differences (p <0.05) between months. Conclusions. During the reproductive period, food energy is channeled to ensure reproduction, so that growth slows and sperm quality varies during the reproductive months.