Availability of minerals in rendered meat and bone meal for Nile tilapia: Preliminary observations

A digestibility trial was conducted with 180 Nile tilapia (32.65 ± 4.52 g) fed a reference diet containing 350 g/kg crude protein and 4,500 kcal/kg gross energy. Five different meat and bone meals (MBMs) were evaluated. The test diets compound by 70% of reference diet and 30% of each MBM were elaborated and classified according to ash content: MBM‐430, MBM‐400, MBM‐370, MBM‐340 and MBM‐310. The apparent availability coefficient (AAC) of minerals and the apparent digestibility coefficient (ADC) of dry matter (DM) were subjected to one‐way analysis of variance (p < .05). Differences among ADC and AAC were determined by Tukey's multiple range test (p < .05). When appropriate, a polynomial regression analysis was performed. Linear correlation analyses between MBM chemical composition and the AAC and ADC were performed (p < .01). Higher values of ADC_DM, AAC_Ca and AAC_P were observed in MBM‐310, while low values were observed in MBM‐430. Quadratic effects of ash, P and Ca contents on AAC_Ca, AAC_P and ADC_DM were observed. The AAC_Ca, AAC_P and ADC_DM indicated a negative correlation with ash, P and Ca contents. MBM‐310 exhibited the highest mineral AAC, which could be used as a mineral source for Nile tilapia.     

Performance of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis> postlarvae reared in indoor nursery tanks under biofloc conditions at different salinities and zero-water exchange

Shrimp farming at low salinity is a trend that will continue to grow globally. Performance of Litopenaeus vannamei postlarvae in the nursery at different salinities with a biofloc technology (BFT) system needs to be explored further, as the nursery is currently used as a transitional stage between the hatchery and grow-out ponds. Hence, this study evaluated the effect of seven salinity levels (2, 4, 8, 12, 16, 25, and 35 ‰) on the performance of L. vannamei postlarvae reared with a BFT system and zero-water exchange at 2000 org/m³. Additionally, this study evaluated the water quality of all salinity treatments. After 28 days of culture, the findings showed that, under biofloc conditions, salinity affected the performance of some variables of water quality in some cases, but only the combination of a high nitrite-N concentration (>4 mg/l) and low salinity (2 and 4 ‰) caused up to 100 % shrimp mortality in the first 2 weeks. In the rest of the treatments (8, 12, 16, 25, and 35  ‰), shrimp survival was >72 %. Shrimp mortality was affected by salinity, especially when it decreased from 35–25–16 to 12 and 8 ‰. The organisms reared at low salinities presented lower final weights and specific growth rate than those reared at higher salinities. An inverse relationship was shown between the ion concentration and the final weight of shrimp.     

Latex proteins from the plant Calotropis procera are partially digested upon in vitro enzymatic action and are not immunologically detected in fecal material

Soluble proteins from the latex of Calotropis procera (LP) were investigated in vitro and in vivo for digestibility as the latex has previously been shown to produce considerable toxic effects on animals. The latex is also an important biologically active compound that displays antiinflammatory and antidiarrhea properties. The proteins were digested by the action of trypsin, pepsin or chemotrypsin as revealed by gel filtration and SDS-PAGE analysis. Furthermore, the full LP digestion was easily achieved by protease treatment. Rabbit polyclonal antibodies raised against LP failed to detect cross-reactive molecules in fecal material of experimental rats following 35 consecutive days of LP consumption in water. Similar patterns of electrophoresis were observed for the negligible amounts of protein observed in the fecal extracts of control and test animals. No death or toxic effects were observed among animals. Taken together these results suggest that harmful and toxic effects on animals of the latex from C. procera are present in its rubber and low molecular weight fractions rather than its protein content.     

Distribution and composition of phytosterols and steryl ferulates in wheat grain and bran fractions

Phytosterols and steryl ferulates are bioactive compounds accumulating in the bran and germ of wheat. However, little is known regarding their localisation and composition in the bran layers of the kernel. The aim of this study was to determine the distribution of phytosterols and steryl ferulates in the wheat grain and in the different layers of bran. The wheat fractions, produced by conventional debranning, aleurone separation and a novel electrostatic process, were analysed for phytosterol contents using GC–FID and for steryl ferulate contents using HPLC–UV. The compounds were identified by GC– and LC–MS. Phytosterols and steryl ferulates were concentrated in the bran layers. The steryl ferulates were accumulated in the intermediate layers, whereas the phytosterols were more evenly distributed in the intermediate layers and aleurone cell contents. The phytosterol composition varied within the wheat kernel, while the steryl ferulate composition was similar in different fractions. Sitosterol and campestanyl ferulate were the main compounds. The highest levels of phytosterols (up to 2117 μg/g) and steryl ferulates (up to 703 μg/g) were found in the pearling, aleurone and certain bran fractions. The phytosterol-rich fractions could be utilised in cereal foods to enhance the intake of health-promoting compounds from natural sources.     

Delaying weed adaptation to herbicide by environmental heterogeneity: a simulation approach

BACKGROUND: Environmental heterogeneity in space or time can drive the evolutionary trajectory of an adaptive trait. This concept could be of practical significance in pesticide resistance management that aims to delay the evolution of a resistance allele. Using a population genetics model, the dynamics of herbicide resistance in a weed species was simulated in a heterogeneous environment with alternation of two unrelated herbicides in time, in space or in both time and space. The level of the environmental heterogeneity (habitat grain) was simulated by a variation in the size of the herbicide-treated areas. RESULTS: The model confirms that several strategies based on habitat heterogeneity efficiently slow down and even prevent resistance evolution. For a recessive resistant trait in outcrossing species, a medium level of environmental heterogeneity (intermediate habitat grain) was found to be the best for delaying herbicide resistance, as previously observed for insecticide resistance management. In selfing species or for a dominant resistant trait in outcrossing species, a low level of environmental heterogeneity (coarse-grained habitat) was more efficient in delaying resistance evolution when heterogeneity in both space and time were considered. CONCLUSION: This model suggests that the choice of optimal tactics for delaying herbicide resistance by enhanced heterogeneity in space or time firstly depends on the interactions between the breeding system and the dominance of the resistance allele in the presence of herbicide, then on the value of the fitness cost and lastly on the dominance of this fitness cost.     

The large‐scale removal of mammalian invasive alien species in Northern Europe

Numerous examples exist of successful mammalian invasive alien species (IAS) eradications from small islands (<10 km²), but few from more extensive areas. We review 15 large‐scale removals (mean area 2627 km²) from Northern Europe since 1900, including edible dormouse, muskrat, coypu, Himalayan porcupine, Pallas' and grey squirrels and American mink, each primarily based on daily checking of static traps. Objectives included true eradication or complete removal to a buffer zone, as distinct from other programmes that involved local control to limit damage or spread. Twelve eradication/removal programmes (80%) were successful. Cost increased with and was best predicted by area, while the cost per unit area decreased; the number of individual animals removed did not add significantly to the model. Doubling the area controlled reduced cost per unit area by 10%, but there was no evidence that cost effectiveness had increased through time. Compared with small islands, larger‐scale programmes followed similar patterns of effort in relation to area. However, they brought challenges when defining boundaries and consequent uncertainties around costs, the definition of their objectives, confirmation of success and different considerations for managing recolonisation. Novel technologies or increased use of volunteers may reduce costs. Rapid response to new incursions is recommended as best practice rather than large‐scale control to reduce the environmental, financial and welfare costs. © 2016 Crown copyright. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Selecting cotton yield response function to estimate profit-maximizing potassium fertilization rates for cotton production in Tennessee

Recent research has shown that stochastic yield response functions fit data better than deterministic yield response functions; however, little research exists comparing profit-maximizing fertilizer rates for upland cotton (Gossypium hirsutum L.) using stochastic and deterministic yield response functions. The objective of this research was to determine the most appropriate yield response functional form from which to determine the profit-maximizing potassium (K) rate for cotton in Tennessee. Data were used from a nine-year K fertilizer experiment in Jackson, Tennessee. Quadratic, quadratic-plus-plateau, linear response plateau, and linear response stochastic plateau response functions were estimated to determine the yield response function that best fit the data. The linear response stochastic plateau function was the most suitable yield response function for the data. The profit-maximizing K rate ranged from 65.2 to 74.3 kg K ha^?1. Misspecification of the yield response function recommended over-application of K fertilizer and decreased the producer's short-term profits.     

A specialist-generalist classification of the arable flora and its response to changes in agricultural practices

Background  

Theory in ecology points out the potential link between the degree of specialisation of organisms and their responses to disturbances and suggests that this could be a key element for understanding the assembly of communities. We evaluated this question for the arable weed flora as this group has scarcely been the focus of ecological studies so far and because weeds are restricted to habitats characterised by very high degrees of disturbance. As such, weeds offer a case study to ask how specialization relates to abundance and distribution of species in relation to the varying disturbance regimes occurring in arable crops.     

Anti-Inflammatory Activity of Chitooligosaccharides in Vivo

All the reports to date on the anti-inflammatory activity of chitooligosaccharides (COS) are mostly based on in vitro methods. In this work, the anti-inflammatory activity of two COS mixtures is characterized in vivo (using balb/c mice), following the carrageenan-induced paw edema method. This is a widely accepted animal model of acute inflammation to evaluate the anti-inflammatory effect of drugs. Our data suggest that COS possess anti-inflammatory activity, which is dependent on dose and, at higher doses, also on the molecular weight. A single dose of 500 mg/kg b.w. weight may be suitable to treat acute inflammation cases; however, further studies are needed to ascertain the effect upon longer inflammation periods as well as studies upon the bioavailability of these compounds.