Biochemical modulations in açaí palm (Euterpe oleracea Mart.) under vegetative stages in an agroforestry system of the Amazon

Background : The açaí palm (Euterpe oleracea Mart.) is a species native to the Amazon region, where the largest stock of these palms is located in the state of Pará, Brazil. This species occurs predominantly spontaneously in the plateau and plains areas of the Amazonian estuary. Water deficit is the main limiting factor of plants, negatively regulating the growth, metabolism and productivity of crops. Aim : This study aimed to deepen the ecophysiological and biochemical responses of Euterpe oleracea Mart. to a water deficiency condition in agroforestry systems. Methods : The study was carried out in a defined period of lowest rainfall in the region, which runs from July to October, averaging 58.6 mm for those months, such as location, age, uniformity, health, development, height and diameter of the stipe, in order to determine the biochemical variables. Responses to biochemical components under water deficit such as starch, sucrose and carbohydrates increased for rachis and fruits. Results : The concentrations of ammonia and proteins increased in stems and fruits. For amino acids, the structures that accumulated these organic compounds were fruits and arrow. One of the most representative amino acids against water deficiency is proline, and its increase in plant tissues is due to osmoprotein function, especially for structures such as rachis, fruit and petioles + rachis. Conclusions : Therefore, Euterpe oleracea Mart. presents excellent physiological plasticity to deal with stressful conditions as well as adaptive behavior to overcome this deficiency.     

Physiological short-term response to sudden salinity change in the Senegalese sole (Solea senegalensis)

The physiological responses of Senegalese sole to a sudden salinity change were investigated. The fish were first acclimated to an initial salinity of 37.5?ppt for 4?h. Then, one group was subjected to increased salinity (55?ppt) while another group was subjected to decreased salinity (5?ppt). The third group (control group) remained at 37.5?ppt. We measured the oxygen consumption rate, osmoregulatory (plasma osmolality, gill and kidney Na⁺,K⁺-ATPase activities) and stress (plasma cortisol and metabolites) parameters 0.5 and 3?h after transfer. Oxygen consumption at both salinities was higher than for the control at both sampling times. Gill Na⁺,K⁺-ATPase activity was significantly higher for the 55?ppt salinity at 0.5?h. Plasma osmolality decreased in the fish exposed to 5?ppt at the two sampling times but no changes were detected for high salinities. Plasma cortisol levels significantly increased at both salinities, although these values declined in the low-salinity group 3?h after transfer. Plasma glucose at 5?ppt salinity did not vary significantly at 0.5?h but decreased at 3?h, while lactate increased for both treatments at the first sampling time and returned to the control levels at 3?h. Overall, the physiological response of S. senegalensis was immediate and involved a rise in oxygen consumption and plasma cortisol values as well as greater metabolite mobilization at both salinities.     

Stocking density affects growth and metabolic parameters in the brill (Scophthalmus rhombus)

In this work, the effects of the stocking density on the physiological stress and biometric features of the brill were studied. No differences for survival rate, feeding efficiency, Conversion Index and feeding intake were not detected among the treatments. The growth rate showed an inverse lineal relationship with stocking density, and there were no significant differences between specimens cultured at medium and high density. Plasma cortisol and osmolality were directly related to stocking density, though the former was not significantly different among the treatments. Plasma glucose and lactate significantly increased, while stocking density rose. Triglycerides enhanced significantly in MSD and HSD with respect to LSD cultured specimens. Differences among treatments were not registered for hepatic glucose, triglycerides and amino acids. However, glycogen showed an inverse lineal relationship with respect to stocking density with significant differences between low and high stocking density. Several lipid classes were different among the treatments, with the high-density specimens presenting the highest values. Liver total lipid was not significantly different among the treatments, but total polar lipid was higher in high density. Muscle metabolites did not vary significantly among the treatments. Concluding, the brill showed a clear secondary response to crowding stress through the mobilization of energy substrates to tissues, evoking a reduction in the growth and other biometric parameters.     

The use of biomarkers to assess the health of aquatic ecosystems in Brazil: a review

Organisms in polluted environments are typically exposed to a complex mixture of chemical contaminants. The great concern about the health of aquatic ecosystems has led to the increased use of biomarkers over the past years. The aim of this work was to review the papers published from 2000 to 2015, which used biomarkers to assess the health of aquatic ecosystems in Brazil. A research resulted in 99 eligible papers. More than 80% of studies were conducted in the states of São Paulo and Rio Grande do Sul. Approximately 63% of studies used fish as bioindicator, whereas the micronucleus test and biochemical analyses were the most used biomarkers. A multibiomarker approach was used by 60.6% of studies, while 39.4% used one single biomarker. Furthermore, 68% were field studies and more than 75% of these used control animals sampled at reference sites. A relationship between the biomarker responses and pollution was reported by 87% of studies; however, 43.4% of studies analyzed only one sampling period, limiting comparisons and comprehension about possible seasonal variations. This review evidenced some weak points in studies using biomarkers in Brazil, especially related to the lack of studies in two important biomes (the Pantanal and the Amazon Rainforest) and experimental designs (small sample size, sampling in one single period, use of one single biomarker). Thus, future studies should consider mainly the use of multiple biomarkers, greater sample size, seasonal sampling and water physicochemical parameters to better diagnose the health of aquatic ecosystems.     

The hairy lizard: heterothermia affects anaesthetic requirements in the Arabian oryx (Oryx leucoryx)

Objective

To study the effect of heterothermia on anaesthetic drug requirements in semi-free ranging Arabian oryx and to assess the temperature quotient (Q₁₀) of oxygen consumption.

Growth and elemental composition (C,N, H) in larvae and early juveniles of a South American salt marsh crab,Chasmagnathus granulata (Decapoda: Grapsidae)

The semiterrestrial grapsid crab Chasmagnathus granulata Dana is one of the most predominant inhabitants of brackish salt marsh ecosystems in South America. Its early postembryonic stages were reared in the laboratory from hatching of the first larval stage through the first juvenile crab instar, and changes in the quantity and elemental composition of biomass (measured as dry weight, W; carbon, C; nitrogen, N; hydrogen, H) were investigated in short intervals of time (every 1 or 2 d). In a series of successive developmental stages, the accumulation of biomass per individual can be described as an exponential function of the number of moults. In contrast, the pattern of growth within individual moulting cycles is described with best fit of observed and predicted data as a quadratic function of development time elapsed since last ecdysis. Weight-specific instantaneous growth rates show decreasing trends within the moulting cycle. Cumulative biomass increments during larval development of C. granulata are among the highest on record for brachyuran crabs. The quantities and patterns of larval growth are in this species similar as in most marine brachyuran crabs, for which data are available, but different from those in some other semiterrestrial grapsid crab species, which live in similar brackish water habitats as C. granulata. Hence, the early postembryonic stages of C. granulata do not show special bioenergetic adaptations to the non-marine conditions, which prevail in the adult habitat of this species. This reflects a strategy of larval export to the sea, i.e. a reproductive dependence of this species on the marine environment.     

Multiscalar land suitability assessment for aquaculture production in Uruguay

This article presents a highly detailed territorial assessment for aquaculture production in Uruguay and a methodology to identify the most suitable areas in order to develop the activity. Furthermore, it proposes the basis to generate a dynamic modelling tool of high spatial resolution to support the decision‐making process regarding national aquaculture activities. The modelling structure of aquaculture suitability was developed by the construction of a hierarchical model, combining a multicriteria assessment and a geographic information system. Forty‐one attributes were integrated in six aptitude models: one model for each one of the five common production systems intended to be the most viable in Uruguay and a sixth aptitude indicator that summarizes those five systems, representing the maximum suitability for aquaculture activities. In addition, the hierarchical model allows measurement and identification of relative weights of each model, according to the planning scale, ranging from basin to cell.     

Evaluation of commercial live bakers’ yeast, Saccharomyces cerevisiae as a growth and immunity promoter for Fry Nile tilapia, Oreochromis niloticus (L.) challenged in situ with Aeromonas hydrophila

This study was carried out to evaluate the use of commercial live bakers’ yeast, Saccharomyces cerevisiae as a growth and immunity promoter for Nile tilapia, Oreochromis niloticus (L.). Fish (0.33 g) were randomly distributed at 25 fish per 140-L aquarium and fed a diet containing 0.0, 0.25, 0.50, 1.0, 2.0, or 5.0 g yeast/kg diet for 12 weeks. After the 12-week experimental period, fish of each treatment were challenged by pathogenic Aeromonas hydrophila, which was given by interperitoneal (IP) injection and kept under observation for 10 days to record clinical signs and the daily mortality rate. The growth-promoting influences of bakers’ yeast were observed with fish and the optimum growth, feed utilization, and protein turn-over were obtained with 1.0–5.0 g yeast/kg diet. Also, yeast supplementation increased protein deposition in fish body. Biochemical parameters were improved in fish fed yeast up to 1.0 g/kg diet. Total fish mortality 10-days after IP injection with A. hydrophila and its count after incubation with fish serum decreased with the increase of yeast level in fish diets. However, the lowest fish mortality and bacterial counts were obtained in fish fed 5.0 g yeast/kg. These results indicate that bakers’ yeast supplement is promising as an alternative method to antibiotics for disease prevention in tilapia aquaculture, and the optimum level of live bakers’ yeast is about 1.0 g per kg diet.     

First results on spawning, larval rearing and growth of the wedge sole (Dicologoglossa cuneata) in captivity, a candidate species for aquaculture

The wedge sole is a target species in the fisheries of the Gulf of Cadiz (Spain). Having reared them to commercial size, we have studied reproduction and breeding in captivity of the wedge sole in this work here. The breeders adapt easily to captivity, and they can spawn in less than 1 year in captivity. The relative fecundity is relatively high, 1.06–2.33 · 10⁶ eggs kg⁻¹ per spawning season (mean 1.6 ± 0.1). Larval SGR is high, 7.2 ± 0.2% day⁻¹ (range 5.8–9.1), similar to other cultured flatfish species. In 1 year, some individuals reach market size and can release eggs, registering SGRs of 1.39–1.66% day⁻¹ (mean 1.56 ± 0.01). This species presents some very different characteristics with respect to other farmed flatfishes (turbot, halibut and Senegal sole, mainly), so that it is necessary to develop new techniques to optimise its cultivation. In the present work, the first results are presented on the biology of the wedge sole in captivity.