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

Colostrum is a source of molecules with nutraceutical features that can attenuate the consequences of adverse conditions, such as densification. Thus, the redox balance and tissue development of juvenile Piaractus mesopotamicus subjected to high stocking density and fed diets containing lyophilized bovine colostrum (LBC) were evaluated. Juveniles were distributed into 16 cages making 50 kg fish m-3 and fed diets containing 0, 10, 20 and 30% inclusion of LBC (n = 4). After 30 days, enteric, hepatic, muscular, renal and branchial tissue were sampled for the determination of glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase activity, oxygen radical absorbance capacity (ORAC), lipid peroxidation and protein and nucleotides content. SOD activity and DNA content were higher in 20% LBC compared to the others in the enteric tissue (P < 0.10). ORAC value in erythrocytes was higher in 30% LBC than 0 and 10% LBC (P < 0.10). Juveniles fed 10% LBC showed higher lipid peroxidation in liver than 0 and 20% LBC (P < 0.10) and those fed 20% LBC showed lower protein/RNA ratio compared to the others (P < 0.10). Bovine colostrum determined a decrease in liver protein synthesis and increased in intestinal DNA content with an intake of 20% of this milk secretion. Additionally, LBC increased the protection of the enteric tissue of juveniles from superoxide radicals and blood antioxidant capacity. We conclude that bovine colostrum can be used as a nutraceutical food for fish, with positive effect in redox balance and tissue development in high concentrations of inclusion in the diet, 20 and 30%.

This study aimed to evaluate the hematological profile and relative condition factor of naturally parasitized Nile tilapia from 12 fish farms in southern Brazil. A total of 240 fish were collected from four regions of the state of Santa Catarina. They were anesthetized, and the blood was collected by puncturing the caudal vein. Subsequently, the fish were necropsied for parasitological analysis. The results were compared with the Kruskal-Wallis test, and the correlations were verified with the Spearman test (P < 0.05). The parasitological analysis revealed high infestations by Ichthyophthirius multifiliis on the fish gills of the south and west regions. The presence of Trichodina magna and Trichodina compacta was observed in low intensity on the body surface of fish from all facilities. Trichodina spp. was found in high intensity parasitizing the fish gills of northern, Itajaí valley and western regions, nonetheless, in those regions, the presence of Monogenea, Cichlidogyrus sclerosus, and Cichlidogyrus halli, on fish gills was observed. The hematological profile presented altered parameters, featuring monocytosis and thrombocytopenia, possibly associated with high parasitic intensities. The observed correlations suggest that neutrophils and monocytes are directly involved in an organic defense against parasites. Monocytes are mainly targeted in the defense against I. multifiliis.

Marine environmental changes, including pH changes have been correlated to alterations in the physiology and susceptibility to diseases in cultured organisms at the early stages of development. Metagenomic analysis 16S rRNA was done to evaluate the biodiversity of pediveliger larvae and spat of Crassostrea gigas under acidic pH stress compared to that of larvae at normal pH. The evaluation was carried out in an experimental system with continuous water flow and pH manipulation by CO2 bubbling to simulate acidification (pH 7.384 ± 0.039), taking as reference the current ocean pH conditions (pH 8.116 ± 0.023). The results indicated that a modulation of the bacterial community is present in both pediveliger larvae and spat subjected to acidic conditions. The Rhodobacteraceae and Campylobacteraceae were the most affected families by the change of pH, with increases of Vibrionaceae in pediveliger larvae and of Planctomycetaceae and Phyllobacteriaceae in spat. In summary, this study demonstrates that bacterial communities associated with pediveliger larvae and spat of C. gigas are responsive to changes in acidification.

This study aimed at determining the compelling palatability of different protein hydrolysates for Nile tilapia juveniles (Oreochromis niloticus). Four isoproteic (30% crude protein) and isoenergetic (3,200 kcal kg-1) experimental diets were formulated, with a 5% inclusion level of poultry hydrolysate protein (PHF), or swine liver hydrolysate protein (PHS), or feather hydrolysate protein (PHP) and a control treatment containing 5% of fishmeal (FPE). Four juveniles (2.9 ± 0.01 g) were distributed in 10 L tanks and fed four times a day, and before each feeding event, diets were drawn. The same amount of pellets from each diet was offered, and feeding behaviors were recorded during three minutes for each feeding event, referred to the time of capture of the first pellet, number of pellet rejections, and number of approximations without capturing pellets and quantity of consumed pellets. A significant effect (P < 0.05) was observed regarding a higher consumption of pellets and palatability index for PHF, followed by PHS, FPE, and PHP. Therefore, it was concluded that PHF provided the highest compelling palatability for Nile tilapia juveniles, by displaying a 10.82% increase of the palatability index, 17% of final feed consumption, and presented a rejection number 6.89 times lower than FPE.

Astaxanthin is an essential micronutrient that regulates shrimp physiology, acting as a free radical scavenger, increasing stress resistance, and enhancing the immune response, improving growth and survival in farm-raised organisms. Despite this, accumulation of astaxanthin has not been evaluated regarding rearing conditions of shrimp. Thus, this study aimed to assess the effect of rearing conditions (extensive vs. hyper-intensive) in the accumulation of astaxanthin in tissues of shrimp Penaeus vannamei, using wild juveniles as a reference of the levels of astaxanthin present in the natural environment. The main oxycarotenoid found was astaxanthin, which was mostly accumulated in hepatopancreas (>90%) in esterified form, while mostly free astaxanthin was found in exoskeleton and muscle (<60%). Comparing wild and reared shrimp, the content of esterified astaxanthin was significantly higher in the hepatopancreas of shrimp reared under extensive conditions (191.45 ± 23.08 μg g-1) followed by wild shrimp (144.08 ± 13.92 μg g-1), while low values (3 ± 1 μg g-1) were found in shrimp reared under hyper-intensive conditions. Astaxanthin levels found in farm-raised shrimp were not explained by commercial feeds, since no astaxanthin (only traces of its chemical precursor β-carotene), was found in the six different commercial feeds analyzed for rearing shrimp. Thus, the results may be explained by primary productivity (i.e., phytoplankton) that is consumed as natural food by shrimp in the ponds of farming systems, or by the effect of specific rearing conditions on the microbiota associated with carotenogenesis in the gut of shrimp. In any case, commercial feeds should fulfill all nutritional requirements for shrimp, particularly under stressful conditions as it occurs in hyper-intensive farming.

The freshwater drum Aplodinotus grunniens is a species widely distributed in North America. In the Mexican southeast, this species occurs in the Usumacinta River, where it supports an artisanal fishery. In this regard, the present study was conducted to supply detailed information on the female reproductive cycle of this species. Calculations of gonadosomatic (GSI) and hepatosomatic (HSI) indexes, histological and visual staging of ovaries as well as the staging of oocyte development were applied together to determine the reproductive changes during an annual cycle. The histological analysis revealed the presence of spawning capable females throughout the year, and the distribution frequencies of oocyte diameters displayed the continuous occurrence of mature oocytes, with great data dispersion and different modal groups. These observations were further corroborated by the presence of alternating peaks and drops in the GSI and HSIs, which were correlated with the occurrence of maturing and spawned females. These data, taken together, reveal that A. grunniens from the Usumacinta River is a partial spawner with asynchronous ovarian development and undetermined fecundity that reproduces year-round, but with spawning occurring preferably during the rainfall-flooding season (June to November). The Usumacinta River seems to be a permanently favorable environment for sheltering, feeding and growth of A. grunniens broods, especially during the flooding season. The information generated in this study will be useful for the development of management strategies in the wild as well as for the exploration of A. grunniens as a potential species for aquaculture production in southern Mexico.

On September 16, 2015, an earthquake occurred in Chile, causing a tsunami (T16S) that impacted Coquimbo Bay, where the Punta Teatinos, Elqui River Mouth, and El Culebrón wetlands are located. Changes in the flat topography produced by the T16S in these wetlands are described using Google Earth Pro v. 7.3.2.5491 and in waterbird richness, with data obtained from eBird. The richness of the accumulated species (S = 43), the similarity of the richness (analysis of conglomerates and similarity index of Sorensen) and differences between means of waterbird richness before and after T16S were analyzed statistically. The similarity in the composition of water birds before and after T16S were, Punta Teatinos (0.83), Mouth of the Elqui River (0.86) and El Culebrón (0.91), the latter was the most affected in its flat topography but showed higher similarity before and after T16S. No statistical differences in the mean of waterbird richness were found before and after T16S. The three wetlands were highly resilient. The original flat topography, the vegetation structure and the water bird richness recovered in a year. It is considered that water birds and these wetlands are resilient to disturbances.

Biometric relationships were estimated for the three most important shrimp species on the coasts of the Gulf of California, Mexico. Individuals were obtained from six lagoon systems, and offshore sites along the east coast of the Gulf of California, mainly in the state of Sonora, between March and September of 2015 and 2016. A total of 25,764 individuals of Penaeus stylirostris, Penaeus vannamei and Farfantepenaeus californiensis were analyzed; the length and weight regression for the females, males and combined sexes showed a high correlation between variables. Additionally, some statistically significant differences were found in the linear length and weight relationships (P < 0.05) between sexes. This study reports the length-weight parameters for a key site of the shrimp fishery, it covers a wide range of sizes for each species and was based on the stages late inshore juvenile and offshore of the shrimp lifecycle; as such, this study provides useful information for future estimations of indispensable parameters for stock assessment analyses.

The survival of several fish species in captivity depends on their adaptation to the environmental conditions and the biological characteristics. The objective of the study was to evaluate the influence of different light intensity levels in growth, behavior and skin pigmentation in juvenile of Lophiosilurus alexandri. Fishes were exposed to the following luminosities: 0, 218, 278, and 459 lux. The experiment was conducted for 75 days, in a water recirculation system with controlled temperatures and aeration. Catfish juvenile were distributed in 35 L aquariums, at the density of 0.28 ind L-1. In order to evaluate fish growth, weight, standard-total length, weight gain, food consumption, food conversion, biomass, specific growth rate and survival were measured twice times a month. Also, swimming behavior, skin pigmentation and plasma cortisol levels were evaluated. Light influences L. alexandri feed consumption, food conversion, behavior and plasma cortisol levels. Environments with low light are recommended for the L. alexandri growth.

The shortbill spearfish Tetrapturus angustirostris Tanaka, 1915 is a widespread tropical and temperate species but is relatively rare, with very few published or cataloged records in museums and fish collections. We reported for the first time a specimen of T. angustirostris from the Pacific coast of Mexico, including meristic, morphometric and molecular data, which was caught in the vicinity of Los Cabos, Baja California Sur, Mexico, in November 2015.