A Study of Lipid Bioaccessibility in Canned Sardine (Sardina pilchardus) and Chub Mackerel (Scomber japonicus)

The lipid composition and bioaccessibility in canned sardine (Sardina pilchardus) and chub mackerel (Scomber japonicus) were studied. Triacylglycerols were absent from the bioaccessible fraction in both products and each FA had a different bioaccessibility level. While total fat bioaccessibility was in the 60–64% range, the bioaccessibility of ω6 PUFA and DHA was <55%. Bioaccessibility depended on canned fish product species: fat, EPA, DHA, and ω3 PUFA bioaccessibility levels seemed to be higher in canned sardine than in canned mackerel. Daily consumption of 278 g of canned mackerel or 47 g of canned sardine would ensure the recommended daily intake of EPA+ DHA.     

Dietary organic acids blend alone or in combination with an essential oil on the survival,growth, gut/liver structure and de hemato‐immunological in Nile tilapia Oreochromis niloticus

This study evaluated the effects of dietary supplementation of organic acids blend (OAB) alone or in combination with essential oil, Lippia origanoides (OAE) for Nile tilapia fed supplemented diets for 30 days. Fish (1.1 ± 0.04 g) were fed control (Control), or OAB 0.5% or OAB 0.5% + essential oil 0.125% (OAE) respectively. At the end of the experiment, samples were collected for de hemato‐immunological, histological analysis of the intestine and liver, as well as microbiology of the intestine. The pH of the diets supplemented with OAB and OAE reduced 0.92 and 0.19 respectively. The growth and FCR were unaffected by the treatments, but survival was significantly higher in the OAB treatment. Fish fed the OAB diet showed reduced concentration of total heterotrophic bacteria and Pseudomonas sp. in the intestine. Increased glucose in fish fed OAB and high number of circulating monocytes in fish fed OAE diet were observed. The anterior intestine of fish fed OAE diet showed larger number of goblet cells and increased villi height. The diet supplemented with OAB, mainly, improved the intestinal health and survival of tilapia juveniles and can be used in juvenile production.     

Leaf gas exchange of green dwarf coconut (Cocos nucifera L. var. nana) in two contrasting environments of the Brazilian north-east region

Summary

Leaf gas exchange characteristics of green dwarf coconut were studied in two contrasting environments highlighting the technical aspects of construction of light-response curves in field conditions and its mathematical approach. Site I is at the south-east region of Bahia State in a hot and humid climate area. The contrasting Site II is located at the Pernambuco State in a semi-arid type of climate. Measurements of leaf gas exchange were accomplished using a portable photosynthesis system equipped with an artificial light source. Significant differences were observed between the two sites for the leaf-to-air water vapour pressure deficit and light-saturated (Qi ≥800.μmol m^–2 s^–1) net photosynthesis and stomatal conductance. Mean values of these variables, in that order, were 1.4 and 2.1 kPa, 12.7 and 8.3.μmol CO₂ m^–2 s^–1 and 0.36 and 0.13 mol H₂Om^–2 s^–1 at Sites I and II, respectively. Eight mathematical models relating both net photosynthesis and stomatal conductance with photosynthetically active radiation, were adjusted from the field data. Good results were obtained with the models, mainly when a linear function of leaf-to-air water vapour pressure deficit was included, indicating that the green dwarf coconut stomata show a strong dependence on water vapour pressure deficit.     

Citral and linalool chemotypes of <Emphasis Type="Italic">Lippia alba</Emphasis> essential oil as anesthetics for fish: a detailed physiological analysis of side effects during anesthetic recovery in silver catfish (<Emphasis Type="Italic">Rhamdia quelen</Emphasis>)

The viability using Lippia alba essential oil as an anesthetic for fish was studied, particularly with respect to physiological effects during recovery. Anesthesia of silver catfish (Rhamdia quelen) using 100 and 300 μL L^?1 of two different chemotypes of L. alba essential oil (citral EO-C and linalool EO-L) prevented the increase of plasma cortisol levels caused by handling, but did not avoid alterations in energetic metabolism. Silver catfish did not have increased the levels of thiobarbituric acid reactive species in the kidney and liver during recovery after anesthesia with either EO, avoiding lipid damage. On the other hand, fish anesthetized with EO-C showed higher protein carbonylation levels, superoxide dismutase, catalase, and glutathione S-transferase activities and non-protein thiol group levels in both tissues compared to controls. Our results suggest that both oils show antioxidant capacity, but anesthesia with EO-L does not cause damage to lipids or proteins, only temporary changes, typical of physiological adjustments during recovery from anesthesia. Therefore, EO-L is an effective anesthetic for silver catfish with fewer side effects than EO-C.     

Loss of genetic variability in the captive stocks of tambaqui,Colossoma macropomum (Cuvier, 1818), at breeding centres in Brazil,and their divergence from wild populations

The loss of variability in farmed populations and the risks of interactions with wild populations support the need for the genetic monitoring of species farmed throughout the world. In Brazil, the tambaqui is the most widely farmed native fish species. Despite this, there are no data on the pedigree of the farmed stocks, and the potential for interactions with wild populations in the Amazon basin has raised concerns with regard to the genetic variability of these stocks. The present study analysed sequences of the mitochondrial Control Region and 12 microsatellites to characterize the genetic variability of seven historically important commercial tambaqui breeding centres located in four different regions of Brazil, and compared these sequences with those obtained from individuals collected from a wild population. High levels of genetic diversity were found in the wild population, whereas genetic diversity was reduced in both markers in most captive populations, except for the broodstock located near the Amazon River. High F_ST and D_EST indices were recorded between the wild population and most of the captive stocks analysed. The drastic reduction in genetic diversity found in most captive stocks and the difference between these stocks and the wild population may have been the result of the small size of the founding populations and the absence of breeding management. The renewal of the broodstocks and the application of breeding management techniques are recommended. In the Amazon region, in addition, the use of broodstocks that are genetically very different from local wild populations should be avoided.     

Monitoring cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) germination using ultrahigh-resolution UAS images

Examination of seed germination rate is of great importance for growers early in the season to determine the necessity for replanting their fields. The objective of this study was to explore the potential of using unmanned aircraft system (UAS)-based visible-band images to monitor and quantify the cotton germination process. A light-weight UAS platform was used, which carried a consumer-grade red, green, and blue camera stabilized by a built-in gimbal system. In order to obtain ultrahigh image resolution during the germination stage, the UAS platform was flown at an altitude of approximately 15–20 m above ground. By applying the structure-from-motion (SfM) algorithm, the images were rectified and orthographically mosaicked with a ground sampling distance of approximately 6–9 mm/pixel. A novel solution was then developed for calculating the average plant size and the number of germinated cotton plants according to the leaf polygons extracted from the orthomosaic images. By using the estimated number of germinated cotton plants, the plant density and the cumulative germination rate can also be estimated in a straightforward manner using field-specific parameters. An assessment of the proposed solution was conducted by comparing the estimated number of the germinated cotton plants against ground observation data collected from six cotton row segments. The results demonstrated that the average estimation accuracy achieved 88.6% in terms of identifying the number of the germinated cotton plants. The accuracy may be further improved if images with near infrared band are employed.