Scientific Journals of INIA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria)
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Effect of spirulina (Arthrospira platensis) supplementation on tilapia (Oreochromis niloticus) growth and stress responsiveness under hypoxia
Get PDFSeveral recent studies have shown that Arthrospira sp. supplementation of feeds has a beneficial effect on fish health and growth, but less is known about its possible effects on stress responsiveness. The present study was designed to evaluate using Arthrospira platensis as a feed supplement for Oreochromis niloticus fry, reared in recirculating aquaculture systems. Two isocaloric and isonitrogenous fishmeal-based diets were prepared with 0% and 1% A. platensis and fed to fry, approximately 10 mg live weight at the beginning of the experimental period (n=16 tanks, 8 tanks per treatment), at a feeding rate of 6% live weight, four meals a day for 50 d. The weight gain per tank, specific growth rate and feed conversion ratio were similar among treatments but A. platensis supplementation significantly increased survival (p<0.05). Stress responsiveness was measured in all fish from 12 tanks using a non-invasive two-choice test. All fish from one home tank (n=6 tanks per treatment), were placed into a shaded tank where oxygen levels were slowly reduced. A doorway was then opened to a second illuminated tank with normal oxygen levels and the number of fish that left the home tank were counted. The fish fed A. platensis stayed significantly (p=0.001) longer in the home tank (30.20 min ± 13.22) than controls (17.35 min ± 8.32), suggesting a lower stress responsiveness and a higher tolerance to hypoxia
Use of different waste waters from the leachate of the mushroom production process as foliar fertilizers: Effects on grape amino acids concentration
Get PDFThe production of edible mushrooms presents a serious problem for the environment, since about 5 kg of waste are produced for each kilogram of mushroom. These waste waters have nitrogenous matter. Thus, the aim was to investigate the effect of foliar applications of waste water from the mushroom production process on must amino acid composition during two seasons compared to other nitrogen sources. The treatments were applied to the vineyard at veraison and one week later at a total dose of 0.9 kg N/ha. Amino acids were analysed by HPLC. Results showed that treated mushroom water (Tmw) and mushroom water (Mw) improved the amino acid concentration in both seasons differentially. Tmw applied to the grapevines increased total amino acids concentration from 1479.58 to 1735.90 mg/L compared to untreated grapevines over the second study season. The effectiveness of the applications depends on grapevines nitrogen needs. Under moderate nitrogen conditions, Tmw and Mw applications seem to be more effective than urea and phenylalanine treatments. These results are important in relation to the sustainable management of the agri-food sector
Rearing, bird type and pre-slaughter transport conditions of broilers II. Effect on foot-pad dermatitis and carcass quality
Get PDFA multivariable linear model was used to analyse the incidence of carcass quality defects over one year in a commercial database that included 1,856 flocks of Ross broilers (9,188 shipments, 1,975,420 carcasses inspected). The incidence of foot-pad dermatitis (FPD), scratches and wing and back haematomas was scored and analysed in terms of the effects of transport distance, arrival time to the slaughterhouse, waiting time at the slaughterhouse, maximum outside temperature on the day of transport, feed conversion rate, stocking density, bird type (yellow-skinned females or males, white-skinned females or males and roaster females), thinning (birds transported after thinning, birds remaining after thinning, and non-thinned flocks), bed litter type (rice hulls, chopped straw or wood shavings), and ventilation system (dynamic, static or tunnel). The incidence of FPD was significantly (p<0.001) lower at higher maximum temperatures and higher in flocks with a higher feed conversion rate. FPD also increased with stocking density (kg/m2) and was, on average, 5.0% higher in males than females. Regarding thinning, FPD was 13% lower in birds transported after thinning. Birds raised on chopped straw had more FPD (49.3%), followed by wood shavings (31.1%). Scratches were higher at higher temperatures and increased with transport distance. Birds transported after thinning had 5.8% more scratches than non-thinned birds, while increased stocking density (kg/m2) on the farm tended to increase scratches. Back haematomas were 32.6% higher in birds that were thinned, while wing haematomas increased with stocking density (kg/m2). Back haematomas were also 23.7% higher in males and more common in white-skinned birds
Climatic regionalization of wine grapes in the Hengduan Mountain region of China
Get PDFThe Hengduan Mountain region of China is one of the world's highest altitude and lowest latitude wine grape cultivation areas. This study screened the existing regional indexes; the active accumulated temperature (AAT) for grapes in the growing season was chosen as the heat index, and the dryness index (DI) in the growing season was chosen as the water index for climatic regionalization. An analysis of 90-meter resolution digital elevation model (DEM) data and the corresponding slope degree and direction for the Hengduan Mountain region in the range of 97°E-103°E, 27°N-33°N, as well as daily meteorological data over 30 years (1981-2010) from 53 stations in the study region, were used to establish the AAT and DI models for the northern area of the Hengduan Mountains. According to the multiple stepwise regression method, the interaction terms among different geographical and topographic factors were considered. In addition, the residual errors were interpolated and corrected based on the modeling, and this approach further improved the simulation accuracy of meteorological factors. A regional climatic map of wine grapes was produced according to these results. The model was used to calculate the suitable altitude range for wine grape cultivation in different regions of the Hengduan Mountains. The study shows that the distribution of suitable wine grape cultivation areas in the northern part of the mountain range generally mimics distribution of dry warm and dry hot valleys. The accuracy of the results was confirmed based on the existing locations of vineyards in the Hengduan Mountain region
Stationarity of seasonal patterns in weekly agricultural prices
Get PDFWeekly series of agricultural prices usually exhibit seasonal variations and the stationarity of these variations should be taken into account to analyse price relationships. However, unit root tests at seasonal frequencies are unlikely to have good power properties. Furthermore, movements in actual price series are often not as expected when unit roots are present. Therefore, stationarity tests at seasonal frequencies also need to be applied. In this paper, a procedure to test for the null hypothesis of stationarity at seasonal frequencies was extended to the weekly case. Once critical values were obtained by simulation exercises, unit root and stationarity tests were applied to weekly retail prices of different agricultural commodities in Spain. The most relevant finding was that many unit roots that seasonal unit root tests failed to reject did not seem to be present from the results of seasonal stationarity tests, whereas seasonal unit root tests led to the rejection of some unit roots that seemed to be present according to the results of seasonal stationarity tests. In conclusion, unit root tests should be complemented with stationarity tests before making decisions about the behaviour of seasonal patterns
Short communication: Functional genetic diversity of chestnut (Castanea sativa Mill.) populations from southern Spain
Get PDFAim of the study: To evaluate the adaptive genetic variability of chestnut (Castanea sativa Mill.) populations from southern Spain in relation to bud burst and water stress.Area of study: Andalusia (southern Spain) where many chestnut groves were progressively abandoned and have become ‘naturalized’.Material and methods: A total of 126 chestnut trees from eight populations were assessed by means of nine genic microsatellite loci (expressed sequence tag simple sequence repeat markers) related to bud burst and water stress.Main results: Significant differences in genetic diversity were detected within and among populations, not found with neutral microsatellite markers. The structure analysis indicated the presence of two different gene pools.Research highlights: These results could contribute to the development of conservation strategies for this species in southern areas exposed to the effects of climate change. The genetic diversity of these populations could be useful in minimizing this risk and other predictable factors related to global change
The use of polyethylene glycol to reduce the anti-nutritional effects of tannins in Cistus ladanifer L.
Get PDFAim of study: To evaluate the impact of Cistus ladanifer L. (rockrose) tannins on ruminal degradability and fermentation characteristics and the use of polyethylene glycol (PEG), as feed additive, to mitigate the anti-nutritional effects of rockrose tannins.Material and methods: Aerial parts of rockrose plants were harvested in March, freeze dried and divided in 4 subsamples which were treated with 0, 25, 50 and 75 g of PEG/kg of dry matter (DM). The mixtures were analysed for chemical composition including total phenolics, total tannins and condensed tannins. In situ rumen organic matter (OM) and N rumen degradability was evaluated using three rumen-cannulated rams and ruminal fermentation pattern (volatile fatty acids (VFA), gas production) was evaluated in vitro using a Rumen Simulation Technique (RUSITEC) apparatus.Main results: In situ experiment indicated that the effective degradability of the OM and N increased linearly (p<0.05) with PEG inclusion due to an increase of the degradation rate (p<0.05). RUSITEC data indicated that substrate disappearance and gas and VFA production increased linearly (p<0.05) with PEG inclusion. Research highlights: Inclusion of PEG to C. ladanifer feed was effective to prevent the anti-nutritive effects of tannins. Thus, the use of PEG as feed additive can promote a better utilization of this shrub by ruminants