Soil acidity and poor nutrient use efficiency are major limiting factors as regards output potential on heavy soils, soils which are dominated by high proportions of clay and organic matter, with impeded drainage, high buffering capacity and located in high rainfall areas. Lime is applied in order to counteract these limiting factors and in turn improve agricultural output and productivity. The current study investigates the effects of two commonly used lime products at three comparable treatment rates, ground lime (7.5, 5 and 2.5 tonne/ha) and granulated lime (7.5, 2.5 and 1.5 tonne/ha), applied across three distinct sites. The ability of each lime product and treatment rate to counteract soil acidity, increase nutrient availability and influence soil physical structure was assessed over time. On average across sites, 1 tonne/ha of each lime product increased soil pH by 0.15 and 0.21 pH units between ground and granulated lime, respectively. Site 3 experienced the greatest increase change in soil pH in comparison to the other two sites, largely due to lower clay content and cation exchange capacity. Granulated lime was 5.7 times more expensive than ground lime in its ability to reduce soil acidity. The high treatment rate showed the greatest reduction in soil acidity, aluminium and iron concentration as a mean across all sites. Morgan's soil test phosphorus concentration increased across all sites, with treatment rates having no effect on the rate of increase. There was evidence of reduced soil compaction and lime application showed no negative implication on soil physical structure.

Temperate streams flowing through deciduous forests derive most of their energy and carbon from allochthonous organic matter supplied by the riparian vegetation mostly during the autumnal litter fall. The decomposition of this coarse particulate organic matter (CPOM) supports the aquatic foodwebs throughout the year. During the decomposition process, part of the CPOM is converted into fine particulate organic matter (FPOM). In this study, we assessed the relationships among decomposition rates of a dominant litter species, oak leaf litter (estimated by the litter bag approach in the presence and absence of macroinvertebrates), benthic CPOM stock and FPOM flux over 12 months in a temperate mountain oligotrophic stream. We also assessed the relationship between these organic matter variables and environmental variables over the same period. As expected from the seasonality in temperature, litter decomposition rates varied over the year and were positively correlated with water temperature and dissolved phosphorus concentration. However, benthic CPOM stock did not significantly change over the year; the higher rainfall in winter and the higher litter decomposition in spring might have compensated for each other in keeping the CPOM stock fairly constant year round. FPOM flux was positively correlated with litter decomposition rates as expected, and this relationship was primarily driven by the activities of detritivores and not of microbes. We can anticipate changes in the carbon cycle, both locally and downstream, if oligotrophic montane streams are subjected to temperature increases (e.g., due to removal of riparian vegetation or in a global warming scenario) and nutrient enrichment from effluents or agricultural activities.

We investigated postprandial changes in transcript abundance following a single satiating meal in juvenile Atlantic salmon (Salmo salar L.) (about 70 g body mass) following fasting for 1 week at 12°C. The expression of twenty-three growth-related genes was determined in fast myotomal muscle using quantitative real-time PCR at the following postprandial time points: − 12, 0, 1, 3, 6, 12, 24, 48 and 96 h. The gut was fullest 1–6 h after feeding and emptied within 48–96 h. IGF-I, MyoD1c, MRF4 and myf5 transcripts were sharply up-regulated within 1 h of refeeding and are promising candidate genes involved in a fast-response signalling system that regulates fish myotomal muscle growth. These genes clustered together with MyoD1b and suggest a coordinated regulation to favour resumption of myogenesis as an early response to feeding. Insulin-like growth factor (IGF)-II and the ubiquitin ligase MAFbx/atrogin-1 were initially down-regulated but restored to initial values after 12 h. It is also suggested that local production of IGF-I within the muscle might suppress catabolic pathways depressing MAFbx/atrogin-1.

The spatial and temporal variations of the microphytoplankton communities were examined during four oceanographic cruises conducted between July 2005 and March 2007 aboard the RV ‘Hannibal’. Water thermal stratification started in May–June, and a thermocline established at 20 m depth, but ranged between 25 m during July and more than 30 m during September. The high concentrations of chlorophyll-a were observed during the May–June semi-mixed conditions and were mainly correlated with the concentrations of phosphate, suggesting a potential limitation by this nutrient. The Bacillariophyceae were dominant in the coastal samples, whereas they declined in the offshore area, most likely due to silicate shortage. Cyanobacteriae developed over semi-mixed conditions and at the thermocline depth. Relatively constant abundance of dinoflagellates was observed during the sampling periods from the coast to the offshore area, mainly explained by the high diversity species of this group. The results suggest that some phytoplankton taxa are generally adapted to specific hydrological conditions, whereas the dinoflagellates did not seem to follow this trend. Our findings have important biogeochemical implications in relationship with the export fluxes of the particulate matter throughout the water column.

Soil solarization is used to manage nematodes, pathogens and weeds, but relatively few studies have examined solarization effects on soil mineral nutrients, soil properties and plant tissue nutrients. This study was designed to optimize the duration of solarization treatment for the management of soil and plant nutrients and crop biomass in an agroecosystem utilizing an organic nutrient source. The experiment was a split-plot with treatment duration as the main effect and solarization as the sub-effect. Solarization treatments of 2-, 4- and 6-week durations began on sequential dates and concluded in mid-August. Immediately post-treatment, okra (Hibiscus esculentus L.) seedlings were transplanted into subplots for tissue nutrient analysis. Freshly chopped cowpea [Vigna unguiculata (L.) Walp.] hay was applied to the soil surface directly around the okra seedlings as an organic nutrient source. Immediately following solarization treatment, concentrations of soil K and Mn were higher, while Cu and Zn concentrations were lower in solarized soils than in non-solarized soils. Soil pH was slightly lower in solarized plots. Concentrations of K, N, Mg and Mn in okra leaf tissue were higher in solarized plots than in non-solarized plots, but concentrations of P and Zn were lower in plants grown in solarized soil. Okra biomass was three and four times higher in the 4- and 6-week solarization treatments than in non-solarized treatments. Based on data from this experiment, 4- and 6-week durations of solarization were optimal for increasing crop biomass. The data indicate that solarization has significant effects on soil and plant nutrients. Results of the nutrient analyses suggest that the availability of nutrients from an organic source was not limited by solarization.

This trial was designed to assess the effect of live probiotic consumption on leucine assimilation from fresh and pasteurised yoghurt in volunteers with different lactose digestibility. Thirty-three volunteers (mean age 32, s.d. 7 years) participated in this parallel single-blind study (16 of them with moderate lactose intolerance). Breath samples were taken before and at 15 min intervals over 3-h after the ingestion of fresh and pasteurised yoghurt extrinsically labelled with (1-13C)leucine. The 13C enrichment in breath was measured by isotopic rate mass spectrometry and mathematically converted to a percentage of assimilated leucine (100-%13C-dose in breath) and the assimilation kinetic constant (min− 1). The 13C-leucine assimilation was statistically higher after the fresh yoghurt intake than after the pasteurised product intake (P = 0·032) while the kinetic constant of assimilation was slower in intolerance status (P = 0·014) although a product-related effect (P = 0·445) was not found. In conclusion, fresh yoghurt intake resulted in higher short-term leucine assimilation, while lactose intolerance appears to negatively affect the assimilation rate of leucine from dairy products. These findings offer new insight on acute in vivo amino acid assimilation in the presence of probiotics and moderate lactose intolerance.

Introduction. Banana and plantain (ban+plant) play a substantial role in people’s diet in Cameroon. A survey was carried out in 240 households in four localities to determine the daily consumption of (ban+plant)-derived foods and the contribution of these foods to iron (Fe), zinc (Zn) and vitamin A intake by children of less than 5 years of age and mothers. Materials and methods. The daily consumption level was assessed by a 24-h dietary recall during three consecutive days. The Fe, Zn and β-carotene (precursor of vitamin A) contents of (ban+plant) products were determined and the bioavailability of these micronutrients was estimated using the [phytate:Fe] and [phytate:Zn] molar ratios. Results. On a dry-weight basis, Fe content in (ban+plant)-based foods ranged from (0.78 to 1.32) mg·100 g–1; Zn content from (0.22 to 0.41) mg·100 g–1 and β-carotene content from (336 to 724) µg·100 g–1. Phytate content was between (0.17 and 1.23) g·100 g–1, with [phytate:Fe] and [phytate:Zn] molar ratios above the estimated bioavailability thresholds of 10–14 and 15, respectively, for all dishes. The daily quantities consumed by rural and urban subjects were not significantly different. The daily supply of Fe by (ban+plant) to children and mothers was 5% and 2%; Zn supply was 3% and 4%, respectively. In contrast, the daily vitamin A supply by (ban+plant) foods was relatively significant, reaching 13% on average per day for both children and mothers. In certain cases, this contribution was as high as 20%. Conclusion. Estimated bioavailability of Fe and Zn is low in (ban+plant) that, therefore, poorly contribute to Fe and Zn intake in the households. However, (ban+plant) are a good source of β-carotene and can make a substantial contribution to meeting vitamin A requirements of children and their mothers.

In a now classic study, Zinke (1962) showed that a single Pinus contorta tree growing on a sand dune along the coast of California modified the chemistry of the soil underneath its crown. He found distinct patterns of pH, exchangeable cations and nitrogen (N) content moving from the bole outward to the crown drip zone, because the acidic bark and stemflow were concentrated around the bole (Zinke 1962). Subsequent studies in temperate forests have also found tree species to affect soil chemical properties such as pH, organic carbon (C) and rates of N mineralization (Boerner & Koslowsky 1989, Boettcher & Kalisz 1990, Finzi et al. 1998). Presumably, these species-specific effects are caused by inter-specific differences in organic acid exudation, nutrient uptake, litter quality or quantity, decomposition rates or nutrient outputs (Binkley & Giardina 1998, Knops et al. 2002, Rhoades 1997). Regardless of the causes, species-generated soil heterogeneity has implications for stand-level estimates of biogeochemical processes such as soil C storage and N-cycling as well as implications for plant diversity and regeneration (Finzi et al. 1998). Although a number of studies have demonstrated that tree species modify soil environments in temperate forests or monospecific tree plantations in the tropics (Fisher 1995, Rhoades 1997), few studies have investigated these processes in species-rich tropical forests (but see Rhoades et al. 1994).

A grower diet containing barley, wheat and soya-bean meal was expanded at 110°C and subsequently pelleted at 80°C. This processing was evaluated in laboratory tests as well as in digestibility experiments involving 12 barrows with an average initial live weight of 40 kg. The unprocessed control diet was offered as a meal. Each diet was offered ad libitum to six pigs during a 5-week period. The 1st week was an adaptation period and measurements were not carried out. Each pig was used in two 5-day digestibility trials which were performed in weeks 2 and 4. Neither food intake, weight gain nor food: gain ratio during the whole 4-week experimental period, nor apparent faecal digestibility and apparent retention of protein were significantly affected (P > 0·05) by expanding and pelleting the diet. Processing caused an increase in the in vitro protein solubility (P < 0·05) and reduced the dietary contents of free lysine and methionine (P < 0·05) while the contents of available lysine and free threonine and tryptophan were not significantly changed (P > 0·05). Apparent faecal digestibility of crude fibre increased substantially (P < 0·05) when the diet was processed, resulting in significantly lower production of faecal mass (P < 0·05) as well as lowerfaecal moisture content (P < 0·05). These phenomena were parallelled by a smaller water consumption (P < 0·05). Apparent digestibility and retention of phosphorus and calcium were diminished (P < 0·05) when the diet was expanded and pelleted.

We examined the importance of seed size in the early establishment of seedlings of four cotyledonous species restricted to nutrient-impoverished soils in south-western Australia. Experimentally removing cotyledons from seedlings increased mortality and reduced root-penetration, growth rate and final weight of plants after 12 wk, in proportion to seed size. The impact of removal of the cotyledons was least in the smallest-seeded, Eucalyptus loxophleba Benth., grown in the more fertile of two soils, and greatest in the largest-seeded, Hakea psilorrhyncha R. M. Barker, whose growth was otherwise unaffected by soil type. In the smallest-seeded species, cotyledon content of most mineral nutrients increased over time, especially in the more fertile soil, while chlorophyll content showed some decrease by the end of the experiment. In the other species, most nutrients (especially N, P, K and Cu in the less fertile soil) were translocated from the cotyledons to the growing plant, and chlorophyll content declined markedly. The translocated N, P, K, Mg and Cu in these species made up a substantial part of the total plant content by 12 wk after germination, while total Ca and Fe tended to increase in the cotyledons via substantial soil uptake. The results indicate, contrary to reports for some other species, that the cotyledons have an important nutritional function in the early establishment of seedlings in these species. The results also show that, in the larger-seeded species, young seedlings rely to a greater extent on nutrient support from the cotyledons than from the soil. We propose that large seeds might be an adaptation for enhancing establishment in nutrient-poor soils.

The effects of polysaccharides and tannins present in the hulls of field beans (Vicia faba L.) on the digestion of amino acids, starch and lipid were studied in poultry. A control diet without hulls and the same diet substituted with 400 g hulls/kg diet from three different varieties of beans were fed to 3-week-old chicks for 4 d. Digestibility coefficients for amino acids, starch and lipid were calculated from measurements made of these nutrients in the diets and the freeze-dried excreta with the aid of titanium dioxide as a marker. Activities of trypsin (EC 3.4.21.4), α-amylase (EC 3.2.1.1), and lipase (EC 3.1.1.3) in digesta removed from the upper jejunum, sucrase (EC 3.2.1.48) in the gut mucosa from the upper jejunum, and α-amylase and lipase in the pancreas were measured. The hulls were analysed for their polysaccharide and tannin contents. Results showed that the hulls were mostly carbohydrate in composition, with cellulose the predominant polysaccharide. Tannins present in the hulls of two coloured-flowering varieties (Brunette and Minica) were of the condensed type. The diet with tannin-free hulls (white-flowering variety Medes) lowered slightly the digestion of amino acids, starch and lipid compared with the control diet. This effect was believed to be due to inhibition of digestive enzymes, possibly through their adsorption onto the hulls. Diets with tannin-rich hulls (varieties Brunette and Minica) caused a large reduction in the digestion of amino acids, starch and lipid compared with the control diet mainly due to inactivation of digestive enzymes by the formation of tannin–enzyme complexes in the digestive tract. Enzyme activities could be partially restored by the addition of polyvinylpyrrolidone to the digesta. Tannins inactivated trypsin the most, α-amylase to a lesser extent and lipase the least and as a consequence lowered the digestion of amino acids the most, starch to a lesser extent and lipid the least. Tannins did not induce an increased pancreatic production of digestive enzymes, nor did they affect activity of jejunum mucosal sucrase. Condensed tannins from Brunette and Minica hulls were partially extractable in methanol alone, but required acidic methanol for fuller extraction. The vanillin: anthocyanidin ratio suggested that tannins were polymerized to the same degree in the Brunette and Minica varieties, both in the methanol and acidic methanol extracts. Hulls from the variety Minica contained a greater amount of methanol-extractable tannins, the quantity of remaining tannins that required acidic methanol for extraction being the same for both varieties.