Dietary lipid sources for seabream and seabass: growth performance, tissue composition and flesh quality

Due to its traditionally good availability, digestibility and high content of n ? 3 HUFA, fish oil is the main lipid source in fish feeds. However, world demand for this product has grown significantly in recent years, whereas its production, based on fisheries landings, is static. The purpose of the present study was to assess the effect of partial replacement of fish oil in compound diets for gilthead seabream and seabass, by several vegetable oil sources, on growth, dietary fatty acid utilization and flesh quality. Five iso‐energetic and isoproteic experimental diets were formulated (25% lipid content). Fish oil was the only added lipid source in the control (FO) diet, and it was included in the other experimental diets at a level high enough (40% of FO diet) to keep the n ? 3 HUFA levels well over 3% in order to cover the essential fatty acid requirements of these species. Fish oil was replaced by soyabean oil (SO), rapeseed oil (RO) and linseed oil (LO) or a mixture (Mix) of them. Feed intake in all dietary groups was in the range of results obtained for commercial diets in both species, and growth and feed utilization were very good. The results show that, providing a minimum content of essential fatty acids in the diet, it is possible to replace up to 60% of the fish oil by SO, LO and RO or a mixture of them in diets for seabream and seabass, without compromising fish growth. Fatty acid composition of liver and muscle reflected that of the diet, but utilization of dietary lipids differed between these two tissues and was also different for the different fatty acids. Despite reduction in dietary saturated fatty acids by the inclusion of vegetable oils, their levels in fish liver were as high as in fish fed the fish oil diet, whereas, in muscle, levels were reduced according to that in the diet. Linoleic and linolenic acids were accumulated in the liver proportionally to their levels in the diet, suggesting a lower oxidation of these fatty acids in comparison to other 18C fatty acids. Regarding eicosapentaenoic acid (20 : 5n ? 3; EPA), docosahexaenoic acid (22 : 6n ? 3; DHA) and arachidonic acid (20 : 4n ? 6; ARA), these essential fatty acids were reduced in the liver at a similar rate, whereas DHA was preferentially retained in the muscle in comparison with the other fatty acids, denoting a higher oxidation particularly of EPA, in the muscle. Some other PUFA increased despite their low dietary levels in seabream fed LO diets and in seabass fed SO diet, suggesting the stimulation of delta‐6 and delta‐5 desaturase activity in marine fish. Despite differences in fatty acid composition, fillet of fish fed vegetable oils was very well accepted by trained judges when assessed cooked.     

High stocking density produces crowding stress altering some physiological and biochemical parameters in gilthead seabream, Sparus aurata, juveniles

High stocking density has been shown to produce a wide variety of effects on cultured fish populations, such as alterations in behavior and poor feed utilization, resulting in mortality and poor growth. High stocking density has also been reported to produce chronic stress and mobilization of energy sources in fish. There are few studies focusing on the effect of high stocking density on one of the most important marine fish species for Mediterranean aquaculture, gilthead seabream (Sparus aurata). Consequently, this study investigates the effect of high stocking density on juveniles of this species, focusing on effects of stocking density on growth, biochemical composition, immune status and hematology.The results of this study showed that high stocking density produced a chronic stress situation. Plasma cortisol levels increased up to 16.25 ng ml–1 in fish held at high stocking; this value was 4 fold that of fish held at low stocking; density (3.91 ng ml–1 ). As a consequenceof this stressful situation, there was both haemoconcentration and a decrease in alternative complement pathway (ACP), an important component of the immune system of fish (from 167.23 U ml–1 down to 146.37 U ml–1). Haematocrit, haemoglobin concentration and red blood cell count were significantly higher in fish held at high stocking density (43.87%, 10.76 9dl–1 and 3.36 ×106 mm–3, respectively) compared with those fish held at low stocking density (37.21%, 9.32 g/dlg–1 and 2.82 ×106 mm–3, respectively).In addition, high stocking density produced a decrease in hepatosomatic index (from 2.26 down to 2.04) and altered liver fatty acid composition. Oleic acid (18: 1n-9) decreased in liver total lipids of fish held at high stocking density and arachidonic acid (20: 4-n6) and n-3 high unsaturated fatty acids (n-3 HUFA) were reduced in liver polar lipids of those fish. These alterations reflect the effect of stocking density on lipid metabolism to help meet the increased energy demand.     

Agronomic characteristics and carotenoid content of five Bola-type paprika red pepper (Capsicum annuum L.) cultivars

The production of sweet paprika in Spain uses exclusively fruit of Bola-type Capsicum annuum L. This work describes the evaluation of the agronomic behaviour of five new cultivars of the Bola-type paprika red pepper, selected in the Instituto Murciano de Investigación y Desarrollo Agrario y Alimentario (IMIDA), and grown in Extremadura for 3 years. The colour and the pigment content of the paprika elaborated following the traditional procedure of La Vera were also studied.     

Inventory Procedures for Smallholder and Community Woodlots in the Philippines: Methods,Initial Findings and Insights

This paper details the processes and challenges involved in collecting inventory data from smallholder and community woodlots on Leyte Island, Philippines. Over the period from 2005 through to 2012, 253 woodlots at 170 sites were sampled as part of a large multidisciplinary project, resulting in a substantial timber inventory database. The inventory was undertaken to provide information for three separate but interrelated studies, namely (1) tree growth, performance and timber availability from private smallholder woodlots on Leyte Island; (2) tree growth and performance of mixed-species plantings of native species; and (3) the assessment of reforestation outcomes from various forms of reforestation. A common procedure for establishing plots within each site was developed and applied in each study, although the basis of site selection varied. A two-stage probability proportion to size sampling framework was developed to select smallholder woodlots for inclusion in the inventory. In contrast, community-based forestry woodlots were selected using stratified random sampling. Challenges encountered in undertaking the inventory were mostly associated with the need to consult widely before the commencement of the inventory and problems in identifying woodlots for inclusion. Most smallholder woodlots were only capable of producing merchantable volumes of less than 44 % of the site potential due to a lack of appropriate silviculture. There was a clear bimodal distribution of proportion that the woodlots comprised of the total smallholding area. This bimodality reflects two major motivations for smallholders to establish woodlots, namely timber production and to secure land tenure.     

Management of a caseous lymphadenitis outbreak in a new Iberian ibex (Capra pyrenaica) stock reservoir

Background

In 2010, an Iberian ibex (Capra pyrenaica hispanica) stock reservoir was established for conservation purposes in north-eastern Spain. Eighteen ibexes were captured in the wild and housed in a 17 hectare enclosure. Once in captivity, a caseous lymphadenitis (CLA) outbreak occurred and ibex handlings were carried out at six-month intervals between 2010 and 2013 to perform health examinations and sampling. Treatment with a bacterin-based autovaccine and penicillin G benzatine was added during the third and subsequent handlings, when infection by Corynebacterium pseudotuberculosis was confirmed. Changes in lesion score, serum anti-C. pseudotuberculosis antibodies and haematological parameters were analyzed to assess captivity effects, disease emergence and treatment efficacy. Serum acute phase proteins (APP) Haptoglobin (Hp), Amyloid A (SAA) and Acid Soluble Glycoprotein (ASG) concentrations were also determined to evaluate their usefulness as indicators of clinical status.Once in captivity, 12 out of 14 ibexes (85.7%) seroconverted, preceding the emergence of clinical signs; moreover, TP, WBC, eosinophil and platelet cell counts increased while monocyte and basophil cell counts decreased. After treatment, casualties and fistulas disappeared and both packed cell volume (PCV) and haemoglobin concentration significantly increased. Hp, SAA and ASG values were under the limit of detection or showed no significant differences.

Conclusions

A role for captivity in contagion rate is suggested by the increase in antibody levels against C. pseudotuberculosis and the emergence of clinical signs. Although boosted by captivity, this is the first report of an outbreak of caseous lymphadenitis displaying high morbidity and mortality in wild ungulates. Treatment consisting of both vaccination and antibiotic therapy seemed to prevent mortality and alleviate disease severity, but was not reflected in the humoural response. Haematology and APP were not useful indicators in our study, perhaps due to the sampling frequency. Presumably endemic and irrelevant in the wild, this common disease of domestic small ruminants is complicating conservation efforts for the Iberian ibex in north-eastern Spain.     

Analysis of water application cost with permanent set sprinkler irrigation systems

In order to identify the subunit design incurring the lowest costs, it is necessary to consider various factors, thereby assuring the correct hydraulic performance of the subunit. Water application costs with a sprinkler irrigation system comprise: investment cost (pumps plant, pipes, sprinklers, ditches), energy, manpower, maintenance and water costs. This work analyses the influence of different design and performance factors, such as subunit arrangement, spacing, working pressure, average application rate, and application efficiency on water application costs in a permanent set sprinkler irrigation subunit. The results show that the most important factor is the spacing between sprinklers. The next most important factor is the shape of the subunit (number of laterals and number of sprinklers per lateral). Working pressure is important too, since a decrease in pressure will result in a decrease in energy costs, although pipe diameter will need to increase. The higher the average application rate of the system, the higher the water application cost. The influence of irrigation efficiency is higher as water price increases. The water application cost can be reduced by 40% when application efficiency increases from 60% to 90%.Communicated by A. Kassam     

Resveratrol treatment controls microbial flora, prolongs shelf life, and preserves nutritional quality of fruit

Resveratrol is known as a grapevine secondary metabolite with fungicide activity. Its exogenous application on harvested grapes resulted in the reduction of microbial flora growth, and consequently, prolonged shelf life, without affecting the nutritional quality of the fruit. Resveratrol treatment also resulted in being effective on fruit that normally does not accumulate such metabolites as, for example, tomatoes, apples, avocado pears, and peppers. As a result, all treated fruits maintained their post-harvest quality and health longer than the untreated ones. This study demonstrates the potential use of resveratrol as a natural pesticide to reduce post-harvest fungi development on a broad spectrum of fruit types.     

The prevalence of Salmonella enterica in Spanish feed mills and potential feed-related risk factors for contamination

A cross-sectional study was conducted in Spain to estimate the prevalence of Salmonella enterica in feed mills and to identify and evaluate potential risk factors associated with feed contamination. A total of 3844 samples were collected from 523 different feed mills using a stratified sampling method. Samples were tested for the presence of Salmonella using conventional culture methods. When the presence of Salmonella was detected, samples were further characterised using serotyping at the National Reference Laboratory (NRL) for animal feed. Additional data about the biosecurity and hygiene measures, feed material used and compound feed produced, were collected by official veterinarians using a questionnaire in situ. In 144 of the feed mills visited (28%), Salmonella were present. However, it was only isolated from 4.8% of samples taken from all of the feed mills (3.5% from feed materials, 3.2% from compound feed and 12.5% from dust of the feed mill facilities). Salmonella serovars of public health importance (Enteritidis, Typhimurium, Infantis, Virchow and Hadar), were detected in only 2.7% of feed mills and in 0.3% of the samples studied. Logistic regression was used to investigate potential feed-mill risk factors for the isolation of Salmonella. Feed mill intake pits were demonstrated to have an increased risk of culture-positive dust samples (OR=6.4; 95% CI: 2.7-15.1). The feed material used in the production of compound feed was associated with recovery of Salmonella. Of the feed material used, cotton seeds were identified as having the highest odds of contamination (OR=3.8; 95% CI: 1.7-8.3). Pelleting appears to reduce the chance of contamination because non-pelleted compound feed is 8 times more likely to be contaminated than pelleted compound feed (OR=8.2; 95% CI: 2.5-26.6). The role of the feed itself in the epidemiology of Salmonella seems to be of limited importance as compound feed is not frequently contaminated at the feed mill level. This should not preclude Salmonella control measures from including all stages of feed production and they should have a risk-based approach according to the findings of this study.     

Lead, Zinc, Arsenic and Copper Pollution in the Alluvial Plain of a Mining Wadi: The Beal Case (Cartagena–La Union Mining District, SE Spain)

The distribution and mobility of heavy metals in the non-saturated zone of the alluvial plain of a wadi in the Cartagena–La Union mining district was investigated. The elemental chemistry of soils, in-depth sediments and different plant species (namely Hirsfeldia incana, Ditrichia viscosa and Piptatherum miliaceum) was carried out by using X-ray fluorescence and X-ray diffraction techniques. Potential mobility of metals was assessed by using lixiviation test runs (DIN 38414-S4). Concentrations detected in soils and sediments were higher than the acceptable limits reported in official regulations. Regarding metals mobility, values obtained for Pb, Zn and As exceed the limits established by European Union for DIN 38414-S4 leachates. Whilst the obtained leaching percentages for Pb, Cu and As were not especially high (<2%), Zn exhibit a very high leaching potential (up to 60% of the total metal content), involving potential risk of pollution events.