Soil Chemical Analysis

Cause, conseguenze e strategie di mitigazione Proponiamo il primo di una serie di articoli in cui affronteremo l’attuale problema dei mutamenti climatici. Presentiamo il documento redatto, votato e pubblicato dall’Ipcc - Comitato intergovernativo sui cambiamenti climatici - che illustra la sintesi delle ricerche svolte su questo tema rilevante.

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Climate Change 2007: The Physical Science Basis.

Continued growth and intensi¢cation of aquaculture production depends upon the development of sustainable protein sources to replace ¢sh meal in aquafeeds. This document reviews various plant feedstuis, which currently are or potentially may be incorporated into aquafeeds to support the sustainable production of various ¢sh species in aquaculture. The plant feedstuis considered include oilseeds, legumes and cereal grains, which traditionally have been used as protein or energy concentrates as well as novel products developed through various processing technologies. The nutritional composition of these various feedstuis are considered along with the presence of any bioactive compounds that may positively or negatively aiect the target organism. Lipid composition of these feedstuis is not speci¢cally considered although it is recognized that incorporating lipid supplements in aquafeeds to achieve proper fatty acid pro¢les to meet the metabolic requirements of ¢sh and maximize human health bene¢ts are important aspects. Speci¢c strategies and techniques to optimize the nutritional composition of plant feedstuis and limit potentially adverse eiects of bioactive compounds are also described. Such information will provide a foundation for developing strategic research plans for increasing the use of plant feedstuis in aquaculture to reduce dependence of animal feedstuis and thereby enhance the sustainability of aquaculture.

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Expanding the utilization of sustainable plant products in aquafeeds: a review

Communities of microscopic plant life, or phytoplankton, dominate the Earth's aquatic ecosystems. This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities in lakes and rivers and oceans. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology, developing an appreciation of assembly processes, co-existence and competition, disturbance and diversity. Although focussed on one group of organisms, the book develops many concepts relevant to ecology in the broadest sense, and as such will appeal to graduate students and researchers in ecology, limnology and oceanography.

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The Ecology of Phytoplankton

The repeatability of behaviour: a meta-analysis.

Protein, lipid, and energy metabolism in eleuthero-embryos and starving larvae of the African Catfish (Clarias gariepinus Burchell).

Assessing farmers' motives for livelihood diversification in the Mekong delta: household life cycle, virtual farm size, and index of integration

The effect of two dietary electrolyte balance (dEB, Na+ + K+ – Cl-) levels (–135 and 145 mEq/kg diet) on heat production, energy and nitrogen retention in piglets was assessed. The experiment consisted of a 13-day adaptation period and a 7-day balance period in two open-circuit climate respiration chambers. Nine groups of three (4 weeks old) crossbred barrows were assigned to one of two diets (five and four groups for –135 and 145 mEq/kg dEB diets respectively). During the balance period, diets were provided at 2·3 times the energy requirement for maintenance in two equal meals daily. Total heat production for each group was determined every 9 minutes from the exchange of CO2 and O2. Faeces and urine mixture was quantitatively collected during the balance period to measure energy and nitrogen balance. Total heat production and metabolizable energy costs for maintenance tended (P 0·10) to be higher in the 145 mEq/kg dEB group (681 and 443 kJ/kg0·75 per day respectively) than in the –135 mEq/kg dEB group (660 and 412 kJ/kg0·75 per day respectively). Differences in total heat production between the two dEB groups mainly occurred in the daytime (light period), when significance level was P 0·01. The respiratory quotient and energy retention as fat were numerically (but not statistically significantly) lower in the 145 mEq/kg dEB group compared with –135 mEq/kg dEB. In conclusion, energy balances were similar for both treatments. However in the daytime (light period), piglets needed more energy for maintenance after ingesting a diet with a dEB level of 145 mEq/kg compared to a diet with a dEB level of –135 mEq/kg at a restricted feeding level.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/182E823440EFCA4785FF98A387D9C66F/S1357729800052462a.pdf/div-class-title-effect-of-dietary-electrolyte-balance-on-metabolic-rate-and-energy-balance-in-pigs-div.pdf

Effect of dietary electrolyte balance on metabolic rate and energy balance in pigs

Fish-borne zoonotic trematodes (FZTs) can cause pathology in humans. Fish weight was reported as important risk factor for transmission from snail to fish. However, in fingerlings, the relation between fish weight and infection is unknown. Aim was quantifying the effect of fish weight on infection probability, attack rate, and metacercariae burden of FZTs in common carps (Cyprinus carpio) between 1 and 20 g. Fish were either used as controls (n = 66) or exposed to 250 parapleurolophocercous cercariae (n = 254). Fish weight was analysed as continuous explanatory variable or classified in four categories with average weights of 0.7 g (n = 116), 4.0 g (n = 58), 8.2 g (n = 57) and 14.2 g (n = 23). The inverse relation between percentage of fish with metacercariae and fish weight is reflected in lower percentages of infected fish at higher weights [%infected = 100/(1 + e[-2.02+0.15 fish weight (g)]); p < 0.01], i.e. 89 %, 85 %, 63 % and 61 %, respectively, in the four groups. Control fish did not get infected. Attack rates were 0.0087, 0.0073, 0.0040 and 0.0033 fish infected per cercariae, respectively; the first two attack rates being significantly higher than the latter two. Mean number of metacercariae per weight group was 5, 5, 2 and 1, respectively, (p < 0.05), with an inverse relation using weight as continuous explanatory variable [p < 0.01; number metacercariae = e1.76-0.13fish weight(g)]. Concluding, an inverse relation exists between fish weight and probability of infection, attack rate and parasite burden in common carp fingerlings. Reducing transmission to fingerlings might be an effective intervention method to improve food safety, reduce the absolute amount of FZTs in the environment and eventually reduce incidence in humans.

Johan A.J. Verreth

Papers

Protein, lipid, and energy metabolism in eleuthero-embryos and starving larvae of the African Catfish (Clarias gariepinus Burchell).

Assessing farmers' motives for livelihood diversification in the Mekong delta: household life cycle, virtual farm size, and index of integration

Effect of dietary electrolyte balance on metabolic rate and energy balance in pigs

Higher attack rate of fish-borne trematodes (Heterophyidae) in common carp fingerlings (Cyprinus carpio) at lower fish weight

Effect of different iron sources on the alleviation of nutritional anaemia in common sole (Solea solea)