Evaluation of immune response and performance of silver catfish fed functional linseed fibres in response to hypoxia stress

This study was conducted to evaluate the immunostimulating activity and growth promoting of diets supplemented with different rations of soluble and insoluble linseed fibre to Rhamdia quelen under hypoxia‐induced acute stress. For this reason, soluble and insoluble fractions of linseed fibre were concentrated separately and combined into four ratios (1:0.5; 1:1; 1:2 and 1:4), which were added to the diets of silver catfish (6.43 ± 0.12 g) and evaluated in a biological assay, along with a control diet (without addition of linseed fibre). After being fed the experimental diets for 45 days, specimens of silver catfish were submitted to hypoxia‐induced acute stress. They were kept out of water for 60 s. Immediately afterwards, blood and cutaneous mucus were collected for subsequent determination of immunological indicators and stress. After stress, the fish were weighed and measured for performance parameter calculation. The experimental design was completely randomized with five treatments and four replications. The data underwent analysis of variance and the means were compared by Tukey's test (p < .05). The fish fed diets containing the 1:2 and 1:4 soluble:insoluble fibre ratios, showed higher total protein content, globulin, plasma alkaline phosphatase activity, and performance in addition to higher mucoprotein content in the cutaneous mucus of the fish. Regardless of their ratio in the diet, linseed fibre provided higher plasma levels of total immunoglobulins and reduction in cortisol levels. The 1:1, 1:2 and 1:4 diets led to higher levels of total immunoglobulins and alkaline phosphatase activity in cutaneous mucus. The results indicate that linseed fibre has a stress‐ reduction, immunostimulant and a growth promoter effect on silver catfish. The 1:2 or 1:4 soluble: insoluble fibre ratios provided greater stimulation of the target immunological indicators and performance.     

Managing threats and restoring wetlands within catchments of the Great Barrier Reef,Australia

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Productive performance of brown mussels Perna perna (Linnaeus, 1758) cultivated on ropes at low densities in Caraguatatuba,Brazil

In Brazil, mussel seed are not a plentiful natural resource, and so the efficient use of seeds by reducing stocking densities should be considered. There are very few studies addressing the relationship between seeding density and growth of mussels in tropical conditions. This work aimed to determine the influence of low seeding densities on the productive performance of Perna perna (Linnaeus) mussels cultivated on ropes in Caraguatatuba, Brazil. In October 2014, 12 ropes, one metre in length each, were seeded at the densities of 200, 300 and 400 mussels/m (four ropes for each density) and suspended on a long line. After 226 days of growing, mussels were harvested and their performance at each density was evaluated in terms of mean weight and length, production, culture efficiency, condition index, survival, amount of recruited seed, amount of fouling on the ropes and morphometric relationships. We observed no significant differences (p > .05) for these indicators among the densities tested, except for mussel biomass, which was significantly higher (p < .05) at the greater densities. A partial budget analysis showed that the density of 400 m^?1 showed better profitability and should be recommended, even in case of seed shortage.     

General and specific combining ability in Serrasalmidae

This work was carried out to predict the combining abilities, both general and specific, for performance traits and bodily yields of Serrasalmidae. Ninety‐six 30‐day‐old juveniles were purchased from two commercial fish farms, 12 of each of the following eight genetic groups: pacu, pirapitinga, tambaqui, tambacu, tambatinga, patinga, paqui and piraqui. Six fish from each genetic group were grown in 500‐L fibreglass tanks (two tanks per genetic group) until they were 495 days old. At the end of the growth period fish were weighed, subjected to morphometric analysis and processed to obtain their bodily yields. Two nuclear markers and one mitochondrial marker were used to confirm the identity of the animals. Combining abilities were obtained using the method proposed by Griffing in 1956 (Australian Journal of Biological Science, 4, 463–493) adapted to a mixed models analysis, environmental effects were estimated by the empirical best linear unbiased estimator method and genetic effects (general and specific combining abilities) were estimated with the empirical best linear unbiased predictor. Predictions of the combining abilities of advanced hybrids were obtained by the mixed models mixture method with normal distributions. Tambaqui showed higher general and specific combining abilities than the other groups for most of the variables, making it the most important genetic group. General combining ability makes a greater contribution to phenotypic variance than specific combining ability for most variables, indicating a predominance of genes with an additive effect in the control of evaluated traits.     

Maximum daily trunk shrinkage and stem water potential reference equations for irrigation scheduling of lemon trees

Measurements of midday stem water potential (ψ_stem) and maximum daily trunk shrinkage (MDS) were done over a 3-year period in adult Fino lemon trees (Citrus limon (L.) Burm. fil.) grafted on sour orange (C. aurantium L.) rootstocks. Plants were irrigated daily above their water requirements in order to obtain non-limiting soil water conditions. The results indicated that reference equations can be obtained for MDS and ψ_stem by pooling data across several seasons using crop reference evapotranspiration (ETo), daily mean vapor pressure deficit (VPD_m) and mean daily air temperature (T _m) in the case of MDS, and ETo in the case of ψ_stem. The best predictor of MDS under non-limiting soil water conditions was T _m, suggesting that MDS reference values can be obtained by means of easy and cheap measurements. MDS and ψ_stem values were not influenced significantly by yield or crop load variations between years. A negative linear relationship between MDS and ψ_stem was found, pointing to an unchanging radial hydraulic conductivity in the bark tissues and suggesting that the MDS is controlled by water potential.     

Detection of post‐F1 fish hybrids in broodstock using molecular markers: approaches for genetic management in aquaculture

Herein, we have developed molecular markers for nuclear genes to use in multiplex‐PCR and PCR‐RFLP, with the goal of characterising hybrid lines derived from crosses between pintado Pseudoplatystoma corruscans and cachara P. reticulatum. These markers, together with others described previously, were used to perform molecular identification analyses as genetic subsidies for Brazilian aquaculture. These analyses were performed due to the problems of high mortality in the offspring reported by the aquaculturist. From a total of 16 broodstock samples, 13 were genetically identified as hybrids; surprisingly, nine of these hybrids were found to be post‐F1 lineages. These data show that the fertility of these animals can seriously affect the cultivated stocks, thus causing financial damage in this aquaculture system. The establishment of PCR‐RFLP and multiplex‐PCR as molecular techniques allows for both the correct management of these animals and the routine monitoring of production and trade of fish hybrids in aquaculture. Consequently, such tools will enable a sustainable development in the aquaculture industry.     

Development of a Suitable Maintenance Diet for Anodonta cygnea

Selenastrum, Chlorella and the Cyanophyta groups, important components of the phytoplankton in the natural habitat of Anodonta cygnea in Mira Lagoon, were used separately as experimental diet for Anodonta cygnea. To assess the effects of the different diets, several organic and inorganic compounds of the haemolymph and extrapallial fluid were measured. Protein content was significantly reduced with experimental Non Feed, and carbohydrate content with Non Feed, Selenastrum, Chlorella , and Cyanophyta diets compared to the control in the lagoon. Lipid contents in body fluids were similar among the different diet groups, with the exception of the Chlorella diet, which showed a higher value. In all diets, the inorganic elements, magnesium and chloride, presented a non-significant variation profile. The concentration of sodium and potassium was significantly affected in Selenastrum and Chlorella diets, observing in the Non Feed diet a minimum value for potassium. The non-significant variation of osmolality suggests the presence of a specific osmotic regulatory mechanism independent of the diet. A particular regulation mechanism seems to exist for both calcium and manganese ion inducing similar profiles for all experimental diets with higher contents in Selenastrum and Cyanophyta diets, respectively. The higher calcium ion concentration appears associated with lower protein-carbohydrate contents, probably due to weak calcium aggregation and deposition mechanism, except for the control and Mixture diets. In general, the concentrations of organic and inorganic compounds in the body fluids of Mixture-fed A. cygnea , were more similar to those found in the control diet group. This suggests that an equal mixture of the three algae, Selenastrum, Chlorella , and Cyanophyta, is more appropriate diet to provide the necessary nutrients for a normal maintenance of A. cygnea in the wild.     

Management of the traumatic oronasal fistula in the cat with a conical silastic prosthetic device

Management of a traumatic oronasal fistula with a prosthetic device in an 8-year-old male neutered domestic shorthair cat is described. The animal had fallen from a height of three stories at the age of 1 year. The fall had resulted in a fracture of the hard palate and a split in the palatal mucosa. Two surgical attempts to close the defect had been unsuccessful and an autopolymerizable acrylic resin prosthesis had produced unsatisfactory results. The management of the chronic traumatic fistula with a conical prosthetic device was fast, easy and efficient. The device was removed and a second one was put in place after 2 years. This method would appear particularly useful for obturation of large palatal defects that have failed to heal after attempts at surgical closure and is an alternative treatment for debilitated cats which may not be candidates for longer surgical procedures.     

The aspartate aminotransferase family in conifers: biochemical analysis of a prokaryotic-type enzyme from maritime pine

Plant aspartate aminotransferase (AAT, EC 2.6.1.1) plays a key role in primary nitrogen assimilation, the transfer of reducing equivalents and the interchanges of carbon and nitrogen pools between subcellular compartments. We investigated the AAT family in conifers using maritime pine as the experimental model. Genes for cytosolic, mitochondrial and two plastidic isoenzymes (eukaryotic- and prokaryotic-types) were identified and their deduced amino acid sequences compared. The primary structure of the eukaryotic-type enzymes is quite well conserved, whereas the prokaryotic-type AAT is highly divergent (15% of identity). These molecular data were confirmed by the absence of immunological cross-reactivity between the two types of native AATs. The mature prokaryotic-type polypeptide was overexpressed in Escherichia coli, and the native enzyme was purified to apparent homogeneity and its molecular properties determined. The fully active recombinant holoenzyme showed highest catalytic activity at 50-60 degrees C and was moderately thermostable, retaining about 50% of its activity after incubation at 70 degrees C for 5-10 min. The presence of pyridoxal 5'-phosphate significantly increased the thermostability of the enzyme. These molecular characteristics were exploited to develop a rapid protocol for the purification of this prokaryotic-type enzyme from pine cotyledons. The results will be useful for studying aspartate and amino acid metabolism in trees.     

Pilot Study Investigating Fecal Shedding of Salmonella spp. by Horses Used in Competition

This pilot study was performed to determine the need for future investigation of the effect of transportation, environmental changes, and athletic competition on fecal shedding of Salmonella spp. in sport horses. Fecal samples were collected once daily from 20 healthy horses that were competing in National Collegiate Athletic Association equestrian event that occurred over a 3-day period. The horses were divided into four groups with five horses per group. The groups were divided based on travel distance. Fresh fecal samples were collected daily and cultured for Salmonella spp., through bacterial culture, for a minimum of 3 days for three groups that traveled to compete and for 15 days for a group that was housed at the competition location. All fecal samples were negative for Salmonella spp. Although this was a pilot study with a small sample size and limited collection days, the results of this study question the effects of the stress of transportation, new environment, and athletic activity on fecal shedding of Salmonella spp. in horses. A larger study, however, is needed to further investigate these findings.