Soil-water and soil physical properties under contour hedgerow systems on sloping oxisols

Hedgerows planted along the contour on steep lands in the humid tropics reduce soil erosion and build terraces over time. The objectives of this study in two Hapludoxes in the Philippines were to evaluate changes after 4 years in soil properties and soil water relations on transects perpendicular to the cropped alleys between four grass and tree hedgerow systems and a control. Hedgerow plants included Gliricidia sepium, Paspalum conjugatum, and Penisetum purpureum. Soil properties evaluated as a function of position in the alley (upper, middle, or lower elevation in an alley) included bulk density, mechanical impedance, soil water transmissivity, water retention, soil water pressure, and soil water content. In general, soil properties were not affected by hedgerow system, but were affected by position in the alley. Nearness to the hedgerow, but not hedgerow species, affected soil water distribution (P = 0.05). Plant available water at the 10–15 cm depth was 0.16 m³ m⁻³, 0.13 m³ m⁻³, and 0.08 m³ m⁻³ for the lower, middle, and upper alley position, respectively. Water transmissivity decreased from 0.49 mm s⁻¹ in the lower alley to 0.12 mm s⁻¹ in the upper alley. The lower soil water contents and soil water pressures in and near the hedgerows confirmed competition for water between the hedgerow species and the food crop in the alley, a condition that is expected to suppress food crop production.     

Preliminary nutritional evaluation of rubber seed and defatted rubber seed meals as plant protein sources for common carp Cyprinus carpio L. juvenile diet

The present study evaluates the use of rubber seed meal (RSM) and its defatted product on the growth and feeding performance of common carp Cyprinus carpio L. Digestibility test using chromium oxide as a tracer showed that defatted RSM (DRSM) resulted in significantly higher total feed, protein, Ca and P digestibility than those of unprocessed RSM (URSM). Growth test was performed with a control and three experimental diets which were 50% DRSM (50% of protein originated from DRSM), 75% DRSM (75% of protein originated from DRSM) and 50% URSM (50% protein originated from URSM). The use of diet containing URSM to replace 50% protein source resulted in the lowest growth and feeding performance which might correlate to the high cyanide content (1.16%) in the diet. Furthermore, providing the fish with this particular experimental diet also caused decline in fish haematological parameters and increased abnormalities in the fish intestine and kidney. Overall results suggested that the use of defatted RSM to replace 50% of other protein sources resulted in a comparable growth and feeding performance of common carp juvenile without any adverse effect.     

Ploidy screening of anthurium (Anthurium andreanum Linden ex André) regenerants derived from anther culture

Anther culture was successfully developed in Anthurium andreanum Linden ex André cv. ‘Tropical’, but resulted in variation in morphology and growth response of regenerants. Ploidy levels varied in different morphological variants. Finding a convenient, rapid, reliable, practical and indirect method to screen and determine anthurium ploidy level is important not only for anthurium, but for ornamentals in general. Regenerants derived from anther culture showing three different ploidy levels (haploids, diploids, triploids) were used in this study. Five indirect methods were used to assess chromosome number: chloroplast number in stomatal guard cells (M1), stomatal length and width ratio (M2), stomatal density (M3), ratio of length and width of leaves (M4), and microspore number per anther (M5). These were compared to chromosome counting as the direct and control method (M6). Through simple regression correlation analysis, when compared to M6, M1 was the most convenient and reliable indirect method to determine the ploidy level. This method was highly and significantly positively correlated to anthurium ploidy level (r = 0.945; p < 0.01). This method could also be applied much faster than the conventional chromosome method.     

Colonization and decomposition of leaf litter by ligninolytic fungi in Acacia mangium plantations and adjacent secondary forests

Colonization of leaf litter by ligninolytic fungi and relationships between mass loss and chemical qualities of surface leaf litter were examined in Acacia mangium plantations and adjacent secondary forests in southern Sumatra Island, Indonesia. Leaves were collected from eight A. mangium plantations of different ages and three secondary forests. Partly decomposed leaves beneath the surface leaf litter were used to measure the bleached area which indicated colonization by ligninolytic fungi. Surface leaf litter was used to measure initial chemical content and subjected to the pure culture decomposition test. The bleached area was greater in secondary forests than in A. mangium plantations. Nitrogen content was higher in all the A. mangium plantations than in the secondary forests, and acid unhydrolyzable residue (AUR) content was generally higher in the A. mangium plantations than in the secondary forests. The bleached area of leaf litter was negatively correlated with nitrogen content of surface leaf litter at all sites, indicating an inhibition of the colonization by ligninolytic fungi of leaves with higher nitrogen content. In a pure culture decomposition test inoculating a ligninolytic fungus to surface leaf litter, mass loss of leaves was negatively correlated with AUR content of surface leaf litter. Mass loss of leaves and AUR was not significantly related to nitrogen content. These results suggested that higher nitrogen content in A. mangium leaf litter had a negative effect by colonization of ligninolytic fungi, but the effect of high N in A. mangium leaf litter on the decomposition of leaf litter and AUR remained unsolved.     

Differential regulation of protein synthesis in skeletal muscle and liver of neonatal pigs by leucine through an mTORC1-dependent pathway

Neonatal growth is characterized by a high protein synthesis rate that is largely due to an enhanced sensitivity to the postprandial rise in insulin and amino acids, especially leucine. The mechanism of leucine’s action in vivo is not well understood. In this study, we investigated the effect of leucine infusion on protein synthesis in skeletal muscle and liver of neonatal pigs. To evaluate the mode of action of leucine, we used rapamycin, an inhibitor of mammalian target of rapamycin (mTOR) complex-1 (mTORC1). Overnight-fasted 7-day-old piglets were treated with rapamycin for 1 hour and then infused with leucine (400 μmol·kg -1 ·h -1 ) for 1 hour. Leucine infusion increased the rate of protein synthesis, and ribosomal protein S6 kinase 1 (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein-1 (4E-BP1) phosphorylation in gastrocnemius and masseter muscles (P < 0.05), but not in the liver. The leucine-induced stimulation of protein synthesis and S6K1 and 4E-BP1 phosphorylation were completely blocked by rapamycin, suggesting that leucine action is by an mTORC1-dependent mechanism. Neither leucine nor rapamycin had any effect on the activation of the upstream mTORC1 regulators, AMP-activated protein kinase and protein kinase B, in skeletal muscle or liver. The activation of eIF2a and elongation factor 2 was not affected by leucine or rapamycin, indicating that these two pathways are not limiting steps of leucine-induced protein synthesis. These results suggest that leucine stimulates muscle protein synthesis in neonatal pigs by inducing the activation of mTORC1 and its downstream pathway leading to mRNA translation.     

Isolation and characterization of antioxidant protein fractions from melinjo (Gnetum gnemon) seeds

The protein from the seeds of melinjo ( Gnetum gnemon ) was purified using a precipitation method and ion exchange chromatographic techniques to identify the potent antioxidant and free radical scavenging activities. Two antioxidant protein fractions were isolated from G. gnemon seed with molecular weights of approximately 30 kDa (Gg-AOPI) and 12 kDa (Gg-AOPII) by SDS-PAGE. The N-terminal amino acid sequence of Gg-AOPII is Gly-Asn-Gly-Lys-Ala-Thr-Val-Ala-Ile-Leu-Val-Lys-Glu-Lys-Val-Glu-Tyr-Gly-Glu-Glu, and the result of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis showed that they were distinct from each other; no protein in database matching was found to both Gg-AOPI and Gg-AOPII. The antioxidant or free radical scavenging activities of Gg-AOPs were investigated by employing in vitro assay systems including the inhibition of linoleic acid autoxidation, scavenging effect on α,α-diphenyl-β-picrylhydrazyl free radical (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), reducing power, chelating abilities of metal ions Cu(2+) and Fe(2+), and protections against hydroxyl radical-mediated DNA damages. The result showed that two protein fractions exhibited significant (p < 0.05) antioxidant activities against free radicals such as DPPH, ABTS, and superoxide anion and showed activities similar to those of glutathione (G-SH) and BHT in a linoleic acid emulsion assay system. Moreover, Gg-AOPI and Gg-AOPII also exhibited notable reducing power and strong chelating effect on Fe(2+) and protected hydroxyl radical induced oxidative DNA damage. The data obtained by the in vitro systems obviously established the antioxidant potency of Gg-AOPs.     

Evaluation of hydrolysed rubber seed meal as a dietary protein source for Nile tilapia Oreochromis niloticus L.

This study evaluated the use of hydrolysed rubber seed meal as a locally grown alternative feed ingredient to reduce the use of fishmeal within formulated feeds for tilapia. Five experimental diets were prepared by formulating different inclusion levels of hydrolysed rubber seed meal (0%, 25%, 50%, 75% and 100% of plant‐based protein contribution). Dried and defatted rubber seed meal was hydrolysed by adding rumen digesta liquid to the ingredient. For digestibility measurement, chromic oxide was added to each diet as an inert marker. The digestibility trial was conducted over a 14‐day period by collecting faecal matter from the rearing tanks. In addition, a growth trial was conducted over a period of 50 days using four replicates per dietary treatment. In both experiments, all fish were fed three times daily to apparent satiation. At the end of growth trial, the inclusion level of hydrolysed rubber seed meal up to 50% of plant‐based protein contribution did not give any significant difference compared to the control diet in terms of feed efficiency, specific growth rate and protein retention parameters. In the digestibility study, fish fed diets containing hydrolysed rubber seed meal up to a 50% of plant‐based protein inclusion level did not give any significant difference compared to the control diet in terms of protein and dry matter apparent digestibility. Based on the result of this growth and digestibility study, up to a 50% of plant‐based protein contribution of hydrolysed rubber seed meal can be used within formulated tilapia feeds without any adverse effect.     

Factors affecting soil loss at plot scale and sediment yield at catchment scale in a tropical volcanic agroforestry landscape

Tropical deforestation and land use change is often perceived as the major cause of soil loss by water erosion and of sediment load in rivers that has a negative impact on the functioning of hydropower storage reservoirs. The Sumberjaya area in Sumatra, Indonesia is representative for conflicts and evictions arising from this perception. The purpose of this study as part of a Negotiation Support System approach was to assess sediment yield both at plot and catchment scale and to relate it to a variety of possible clarifying factors i.e. land use, geology, soil and topography. Sediment yield at catchment scale per unit area, was found to be 3–10 times higher than soil loss measured in erosion plots. A stepwise regression showed that the dominant factors explaining sediment yield differences at catchment scale in this volcanic landscape were a particular lithology (Old Andesites) and slope angle followed by the silt fraction of the top soil. In lithologically sensitive areas soil loss at the plot scale under monoculture coffee gardens decreases over time from on average 7–11 Mg ha^? 1 yr^? 1 to 4–6 Mg ha^? 1 yr^? 1, mainly because of the development of surface litter layers as filters and top soil compaction in the areas without litter, but remains higher than under shade coffee systems or forest. The runoff coefficient under monoculture coffee remains on average significantly higher (10–15%) than under forest (4%) or under shade coffee systems (4–7%). In lithologically stable areas soil loss remained below 1.8 Mg ha^? 1 yr^? 1 and the runoff coefficient below 2.5% under all land use types, even bare soil plots or monoculture coffee gardens. Less than 20% of the catchment area produces almost 60% of the sediment yield. The reduction of negative off-site effects on e.g. the life time of a storage reservoir would benefit greatly from an improved assessment of the lithologies in volcanic landscapes and the consideration of potential sediment source and sink areas. In lithologically sensitive areas, a shift from sun to shade coffee systems may result in reducing surface runoff and soil loss, although water erosion at the plot scale is not the main contributor to sediment yield at the catchment scale. The quantification of land use effects on dominant erosive processes such as river bank and river bed erosion, landslides and the concentrated flow erosion on footpaths and roads can contribute to more targeted efforts and relevant incentives to reduce (or live with) sediment load of the rivers.     

Improved vitellogenesis,gonad development and egg diameter in catfish (Pangasianodon hypophthalmus) supplemented with turmeric (Curcuma longa) powder

An experiment was conducted to study the effect of supplementing catfish (Pangasianodon hypophthalmus) with turmeric (Curcuma longa) on the vitellogenic capacity of the liver as a new method to improve reproductive performance in oviparous animals. The experimental catfish were assigned to a completely randomized design consisting of four doses of supplemental turmeric (0, 1.2, 2.4 and 4.8 g/kg feed) with 10 catfish with body weights ranging from 2 to 4 kg in each group. Blood samples were collected on days 0, 14, 28, 42 and 56 of turmeric supplementation to measure the concentrations of plasma oestradiol‐17ß and vitellogenin. The weights of the body, gonads and liver were measured on days 0, 28 and 56. The fecundities of the catfish were measured on days 28 and 56 of turmeric supplementation, and egg diameters were measured on days 28 and 42. The results showed that catfish supplemented with turmeric at a dose of 2.4 or 4.8 g/kg feed had higher growth rates, higher plasma oestradiol‐17β and vitellogenin concentrations, and higher gonad somatic index values and egg diameters. This is the first report demonstrating that the hepatoprotective activity of the curcumin in turmeric could be used to improve both vitellogenin synthesis, which improves nutrient deposition in the ovulating eggs, and the reproductive performance of teleost fish and oviparous animals.     

Do cannibalistic fish possess an intrinsic higher growth capacity than others? A case study in the Asian redtail catfish Hemibagrus nemurus (Valenciennes, 1840)

This study relied on the day‐by‐day analysis of bioenergetics and prey size preference in larvae and juveniles of Hemibagrus nemurus selected at random, held in isolation (28.5°C, 12L:12D) and feeding ad libitum on conspecifics [21 fish, 12–46 mm total length (TL), dry mass (DM) of 1–145 mg]. Several traits concur to make young H. nemurus highly cannibalistic: (1) high predation capacities (largest prey = 88% and 70% TL in fish of 8 and >40 mm TL, respectively), (2) opportunistic feeding behaviours with no marked size preference and (3) an unusual combination of high food intake (>100% DM at 1 mg DM) and very high gross conversion efficiency (>0.70). A growth model was constructed from the top performances of fish feeding maximally (16 of 21 fish) and indicated that the risk of cannibalism would be high and permanent except for meal frequencies over five daily meals. Cannibals emerging spontaneously under communal rearing (6 fish L^?1, three daily meals) grew more slowly or just at the same rate as predicted by the growth model constructed from siblings selected at random. This indicates that the individuals that become cannibals do not possess higher intrinsic capacities for growth than others.