Cellular activity and development of enteric,hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus (Holmberg 1887) fed with lyophilized bovine colostrum

Bovine colostrum, an alternative food of animal origin provided as partial protein source, may constitute an innovative ingredient in fish feeding. Serum insulin‐like growth factor 1 (IGF‐1) and cellular activity of enteric, hepatic and muscle tissues of juvenile pacu Piaractus mesopotamicus fed with lyophilized bovine colostrum (LBC) were evaluated. Pacu (8.46 ± 0.74 g; 7.75 ± 0.27 cm, n = 18 in triplicate) were stocked into 18 tanks (300 L; 18 fish per tank, in triplicate) and fed with control diet containing 0% of LBC or experimental diet containing 10% and 20% of LBC inclusion for either 30 or 60 days of experiment. IGF‐1 serum concentration was not affected (P > 0.05) by the diet containing LBC and experimental period. The intestinal and hepatic cellular activity was not influenced by LBC (P > 0.05); however, intestine protein/RNA decreased at 60 days (P < 0.05). The muscle cellular activity was affected by LBC, highest in fish fed with diet containing 10% of LBC (P < 0.05). Between the periods DNA and protein/RNA increased at 60 days, while RNA, protein/DNA and RNA/DNA ratio decreased in this same period (P < 0.05). Increased DNA muscle content indicates fish growth by hyperplasia. The results of the present study is related with suitable development of enteric, hepatic and muscle tissues and proper condition of juvenile pacu fed with LBC considering the absence of differences in relation to juveniles that consumed diet without colostrum.     

Antioxidant activity and lipid peroxidation in Artemia nauplii enriched with DHA‐rich oil emulsion and the effect of adding an external antioxidant based on hydroxytyrosol

Artemia nauplii catabolize polyunsaturated fatty acids (PUFA); in particular, they retroconvert docosahexaenoic acid (DHA, 22:6n‐3), so enrichment is a continuous quest towards increasing PUFA through the use of PUFA‐rich enrichment products. However, optimal conditions during enrichment (aeration, illumination and temperatures around 28°C) tend to accelerate autoxidation of PUFA and the formation of potentially toxic oxidation products. Water‐soluble antioxidants like the polyphenolic compound hydroxytyrosol (3,4‐dihydroxyphenylethanol), a polar molecule found in the water fraction resulting after the milling process of olives, arise as promising compounds to prevent oxidation during Artemia enrichments. We investigated the antioxidant activity and lipid peroxidation in Artemia nauplii during enrichment and the effect of adding an external antioxidant based on hydroxytyrosol during the enrichment with a PUFA‐rich emulsion (M70). For this purpose, the activity of antioxidant enzymes (catalase, superoxide dismutase, glutathione‐S‐transferase, glutathione peroxidase), as well as lipid peroxidation, was determined in enriched and unenriched Artemia nauplii. To validate antioxidant activity and lipid peroxidation, in a first experiment, nauplii were enriched with microalgae (Tetraselmis suecica), yeast (Saccharomyces cerevisiae) and M70 emulsion. In a second experiment, enrichment with a commercial emulsion (DC Super Selco), M70, and a combination of M70 and hydroxytyrosol (Hytolive, HYT) added as an external antioxidant were performed. The combination of M70 with HYT produced the best results, in terms of activity of antioxidant enzymes. The analysis of the fatty acids from total lipids showed that the addition of hydroxytyrosol preserved the DHA percentage of enriched nauplii.     

Liver histology and histomorphometry in hybrid sorubim (Pseudoplatystoma reticulatum × Pseudoplatystoma corruscans) reared on intensive fish farming

This study aimed to characterize the liver histology and histomorphometry in sorubim hybrid of different categories (nursery, growth and grow‐out) reared on fish farming. The categories were defined considering body weight (BW): nursery category (n = 5): BW = 37.06 ± 6.00 g (31.6–45.3 g); growth category (n = 5): BW = 310.40 ± 53.80 g (242.1–376.4 g) and grow‐out category (n = 5): BW = 874.28 ± 27.59 g (846.2–913.1 g). Liver fragments were processed to paraffin inclusion, and sections were stained by haematoxylin and eosin (H&E), PAS (Periodic Acid Schiff) and Perl's staining to histology, histomorphometry and density volumetric of liver structures; glycogen analysis and to detect ferric irons (Fe³⁺) respectively. The hepatosomatic index decreased between the categories (P < 0.01). The percentage of PAS‐positive hepatocytes in the nursery category was higher (P < 0.05) in relation to the growth and grow‐out categories. The hepatocytes from all fish were positive to Perl's staining. The density volumetric of liver structures did not differ among categories except to blood vessels were higher (P < 0.01) in the nursery and growth. The area (μm²) and perimeter (μm) of hepatocytes, and the area (μm²), perimeter (μm) and volume (μm³) of the nuclei from grow‐out fish were lower (P < 0.01) than those from the nursery and growth categories. Changes in morphometric characteristics of hepatocytes may result from metabolic changes associated with body growth surubins; therefore, these morphometric characteristics of liver tissue can be used as functional biomarkers for the assessment of fish health and nutrition status.     

Is it possible to differentiate between environmental and fishery effects on abundance‐biomass variation? A case study of blackspot seabream (Pagellus bogaraveo) in the Strait of Gibraltar

We assessed the potential for simulation and modelling of the blackspot seabream (Pagellus bogaraveo) population in the Strait of Gibraltar to discriminate the environmental effects of fishery impacts. A discrete biomass–abundance dynamic model was implemented to obtain a simulated monthly time series of blackspot seabream biomass. On this simulated time series, autoregressive integrated moving average (ARIMA) models were fitted. The best ARIMA fit provided a significant correlation of 0.76 and persistence index higher than 0.85. The proportion of variance non‐explained by the ARIMA models was correlated with a time series of sea surface temperature (SST) and North Atlantic Oscillation (NAO). The analysis of global, annual and winter correlation between the proportion of variance not explained by the ARIMA models and environmental variables showed that significant associations were not detected over the full time series. Our analysis therefore suggests that overexploitation is the main factor responsible for the commercial depletion of blackspot seabream in the Strait of Gibraltar.     

A 3-year assessment of nitrous oxide emission factors for urine and dung of grazing sheep in a subtropical ecosystem

Purpose

Grazing livestock has strong impact on global nitrous oxide (N₂O) emissions by providing N sources through excreta. The scarcity of information on factors influencing N₂O emissions from sheep excreta in subtropical ecosystems such as those of Southern Brazil led us to conduct field trials in three different winter pasture seasons on an integrated crop–livestock system (ICL) in order to assess N₂O emission factors (EF-N₂O) in response to variable rates of urine and dung.

Materials and methods

The equivalent urine-N loading rates for the three winter seasons (2009, 2010, and 2013) ranged from 96 to 478 kg ha^?1, and the dung-N rates applied in 2009 and 2010 were 81 and 76 kg ha^?1, respectively. Air was sampled from closed static chambers (0.20 m in diameter) for approximately 40 days after excreta application and analyzed for N₂O by gas chromatography.

Results and discussion

Soil N₂O-N fluxes spanned the ranges 4 to 353 μg m^?2 h^?1 in 2009, ??47 to 976 μg m^?2 h^?1 in 2010, and 46 to 339 μg m^?2 h^?1 in 2013. Urine addition resulted in N₂O-N peaks within for up to 20–30 days after application in the 3 years, and the strength of the peaks was linearly related to the N rate used. Emission factors of N₂O (EF-N₂O, % of N applied that is emitted as N₂O) of urine ranged from 0.06 to 0.34% and were essentially independent of N rate applied. By considering a ratio of N excreted by urine and dung of 60:40, a single combined excretal EF-N₂O of 0.14% was estimated.

Conclusions

Our findings showed higher mean EF-N₂O for sheep urine than that for dung (0.21% vs 0.03%), irrespective of the occurrence or not of urine patches overlap. This value is much lower than default value of 1% of IPCC’s Tier 1 and reinforces the needs of its revision.

     

Genome-wide in silico analysis of SOD genes in common bean (Phaseolus vulgaris L.)

Journal of Crop Science and Biotechnology - Superoxide dismutases (SODs) are a group of enzymes that play essential roles in catalyzing the dismutation of superoxide radicals to protect cells from...     

Assessment of the long‐acting ivermectin formulation in sheep: Further insight into potential pharmacokinetic interactions

The aim of the current study was to evaluate the in vivo pharmacokinetic of ivermectin (IVM) after the administration of a long‐acting (LA) formulation to sheep and its impact on potential drug‐drug interactions. The work included the evaluation of the comparative plasma profiles of IVM administered at a single therapeutic dose (200 μg/kg) and as LA formulation at 630 μg/kg. Additionally, IVM was measured in different gastrointestinal tissues at 15 days posttreatment with both IVM formulations. The impact of the long‐lasting and enhanced IVM exposure on the disposition kinetics of abamectin (ABM) was also assessed. Plasma (IVM and ABM) and gastrointestinal (IVM) concentrations were analyzed by HPLC with fluorescent detection. In plasma, the calculated C_max and AUC_0‐t values of the IVM‐LA formulation were 1.47‐ and 3.35‐fold higher compared with IVM 1% formulation, respectively. The T_1/2ab and T_max collected after administration of the LA formulation were 2‐ and 3.5‐fold longer than those observed after administration of IVM 1% formulation, respectively. Significantly higher IVM concentrations were measured in the intestine mucosal tissues and luminal contents with the LA formulation, and in the liver, the increase was 7‐fold higher than conventional formulation. There was no drug interaction between IVM and ABM after the single administration of ABM at 15 days post‐administration of the IVM LA formulation. The characterization of the kinetic behavior of the LA formulation to sheep and its potential influence on drug‐drug interactions is a further contribution to the field.