Evaluation of micronized lupin seed meal as an alternative protein source in diets for gilthead sea bream Sparus aurata L. juveniles

A 12‐week growth trial was performed to evaluate the effect of lupin seed meal as a protein source in diets for gilthead sea bream (Sparus aurata) juveniles. Six experimental diets were formulated to be isonitrogenous and isoenergetic and to contain 10%, 20% and 30% of raw lupin (Lupinus angustifolius) seed meal protein or 20% and 30% lupin (L. angustifolius) seed meal processed by infrared radiation (micronized) in place of fish meal protein, the only protein source of the control diet. Fish accepted all diets well and no significant differences in feed utilization among groups were noticed during the trial. Final weight of fish fed the experimental diets was identical or higher than the control group. Final weight of fish fed diets including 20% micronized lupin protein was even significantly higher than that of fish fed the fish meal‐based control diet. Moreover, at the same dietary lupin seed meal protein inclusion levels, final weight of fish fed diets including micronized lupin was significantly higher than with raw lupin. A trend was also noticed for a decrease of final weight with the increase in lupin seed meal in the diets. At the end of the trial no significant differences in proximate whole‐body composition, hepatosomatic and visceral indices were observed among groups. It is concluded that lupin seed meal can replace up to 30% fish meal protein in diets for gilthead sea bream juveniles with no negative effects on growth performance. Furthermore, micronization of lupin seeds improves its dietary value for gilthead sea bream juveniles. At the same dietary lupin inclusion levels, diets including micronized lupin seeds promote significantly higher growth rates than raw lupin seeds.     

An AFLP diversity study of the genus Passiflora focusing on subgenus Tacsonia

DNA variation was studied at the intra- andinterspecific levels within the genus Passiflora, with particular emphasis on the subgenusTacsonia and its relationship with the subgenusPassiflora. AFLP fingerprints were generated for35 accessions from 21 species, 14 of which belong to subgenusTacsonia, and four to subgenusPassiflora. The morphologically intermediateP. manicata (subgenusManicata) was also included, as wereP. trinervia (subgenusPsylanthus) and P.alnifolia (subgenus Decaloba). The two latter were used as outgroup species. Twoprimer combinations generated 34–80 scorable fragments pergenotype for a total of 260 fragments. Polymorphism analyses spannedthe levels from individual genotype to section. SubgenusTacsonia presented wide genetic variability atboth intra- and interspecific levels, particularly within wildspecies. The classification based on these markers generally agreeswell with current taxonomic definitions of common species, but lesswith definitions of sections. A geographical component was evident inthe intraspecific variation of P.mixta, P.tripartita var. mollissimaand P. tarminiana, withwider variation in Ecuador and Peru than in Colombia and Venezuela.These same three species, plus P.cumbalensis, formed adjacent clusters, showingcloser affinity with each other than with the other species ofsubgenus Tacsonia. As expected, P. manicata clustered at anintermediate position between subgenera Tacsoniaand Passiflora.     

Organic fertilizers derived from plant materials Part II: Turnover in field trials

Our aim was to investigate two different organic fertilizers derived from plant materials (OFDP) with respect to their nitrogen (N) and carbon (C) turnover in field trials planted with small radish (Raphanus sativus L. var. sativus) and white cabbage (Brassica oleracea L. convar. capitata var. alba) or fallow. The two fertilizers investigated were coarse seed meal of yellow lupin (Lupinus luteus L.) and coarse meal of castor cake (Ricinus communis L.). Under cool spring conditions, the soil turnover of yellow lupin–seed meal was slightly enhanced compared to castor‐cake meal. During the vegetation period of the vegetables, N added with both fertilizers was metabolized more or less completely by soil microorganisms. Due to similar efficiencies of the fertilizers tested, no significant difference could be found in the N uptake of plants. From this point of view, yellow lupin–seed meal, which can be produced by farmers themselves, has the potential to replace the widely used castor‐cake meal. Considerable amounts of N may remain in the field after fertilization with OFDPs either as mineral N or as easily mineralizable organic N. This N should be utilized immediately by a succeeding crop to avoid leaching losses.     

Effects of intensifying organic manuring and tillage practices on penetration resistance and infiltration rate

Soil erosion, along with the contributing factors of soil crusting and sealing, have received minimal scientific attention to date in Latin America. This study was conducted in an Andean hillside environment to determine how the local organic manuring and tillage practices influence the development of soil crusting and sealing, and the extent to which these practices influence soil water infiltration. The aim of this study was to identify treatments that prevented superficial soil structural constraints, i.e. treatments which maintain infiltration and therefore reduce potential soil erosion and run-off.

Treatment results were measured with a pocket penetrometer and a mini-rain simulator on nine different cropping systems, mainly based on cassava (Manihot esculenta Crantz), from February to November 2000 and 2001. The cropping systems were laid out on a Ferrallic Cambisol, an acid, vulcanically influenced soil of the Andean region.

In both cropping cycles, treatments with chicken manure application developed superficial soil crusts during the dry season. For a treatment manured with 8 t ha⁻¹ chicken manure, this crust meant an increase in penetration resistance from 2.3 kg cm⁻² in April 2000 to 16.2 kg cm⁻² in July 2000. The change in superficial soil structure created a notable reduction in final infiltration from 92 to 42.2 mm h⁻¹. A minimum tillage treatment which displayed the highest penetration resistance during the dry periods of up to 46.4 kg cm⁻² presented no restricting effects on soil water intake (76.2 mm h⁻¹ final infiltration in 2000) due to an optimal aggregate development during 10 years of consecutive conservation practice.

Measurements of penetration resistance and infiltration showed that soil conserving treatments, such as minimum tillage and crop rotations, improved the physical soil status and prevented soil crusting developing along with its negative effects on infiltration. These methods can therefore be strongly recommended to farmers.     

Subunit composition of proteins from seeds of Lupinus albus

All the main globulins in the seeds ofLupinus Albus are oligomeric glycoproteins. Legumins (33%) consist of two similar protein molecules which contain protomers linked by disulphide bridges. They result from a partial proteolytic breakdown of an original polypeptide chain. Vicilins (44%) consist of four similar protein molecules with several protomers linked together by non-covalent bonds. Globulin 1 (6%) has a native M.W. of 199 kd and is formed by four 45.0 kd subunits consisting of two smaller protomers (28.0 and 16.0 kd) linked by -S-S- bonds. Globulin 9b (12.5%) has the lowest M.W. (44.0 kd) and is made up of three protomers, two of which are linked by disulphide bonds.     

CADMIUM CONCENTRATION IN YELLOW LUPIN GRAIN IS DECREASED BY ZINC APPLICATIONS TO SOIL BUT IS INCREASED BY PHOSPHORUS APPLICATIONS TO SOIL

Yellow lupin (Lupinus luteus L.), which is grown as a grain legume in rotation with spring wheat (Triticum aestivum L.) on acidic, sandy soils of south-western Australia, accumulates cadmium (Cd) in grain. Application of fertilizer is required to combat zinc (Zn) and phosphorus (P) deficiency for yellow lupin production on these soils, which may affect Cd concentration in grain. In the same field experiment conducted at two sites on acidified sand over clay duplex soils, five Zn levels (0, 0.8, 1.6, 3.2, 6.4 kg Zn ha^-1), as Zn oxide, and three P levels (0, 10, and 20 kg P ha^-1), as triple superphosphate, were applied. At both sites, applying increasing Zn levels decreased Cd concentration in grain, whereas applying increasing P levels increased Cd concentration in grain. The ZnxP interaction was not significant for either grain yield or Cd concentration in grain. At the 8–10 leaf stage, Zn and P concentration was measured in whole shoots (WS), and Zn concentration was also measured in the youngest mature growth (YMG). The concentrations of the elements that were related to 90% of the maximum grain yield (critical prognostic plant test Zn and P) was i) for WS, 29 mg kg^-1for Zn and 3.5 g kg^-1for P; and ii) for YMG, was 23 mg kg^-1for Zn.     

Growth,enzymatic glutathione peroxidase activity and biochemical status of juvenile barramundi (Lates calcarifer) fed dietary fermented lupin meal supplemented with organic selenium

To investigate the effects of high level of lupin meal (LM) supplemented with organic selenium (OS) on the growth and blood biochemistry of barramundi (Lates calcarifer), four isocaloric and isonitrogenous diets were prepared, containing either non‐fermented or fermented LM, and either supplemented with 2 mg OS/kg (LM, LM_OS, FLM and FLM_OS), or not. A fishmeal (FM)‐based diet formulated for juvenile barramundi was used as a control diet. Fish (initial mean weight of 5.88 g) were triplicated and fed the test diets for 75 days. The findings demonstrated that growth performance of fish fed with the FLM and FLM_OS diets were similar to fish fed with the FM diet (p > .05). The antioxidant glutathione peroxidase (GPx) activity, and haemoglobin (Hb) of fish fed with the FLM_OS diet were significantly higher than that of FM‐fed fish (p < .05). Plasma alanine aminotransferase (ALT) activity was significantly increased in fish fed with non‐fermented diets (LM and LM_OS) than in those fed with fermented LM diets (FLM and FLM_OS) (p < .05). However, there were no significant differences in ALT activity among LM_OS, FLM, FLM_OS and FM diets. There was an interaction between the LM and OS on plasma CK activity; the CK of fish fed with diets supplemented with OS was higher in non‐fermented LM diets but lower in fermented LM diets (p < .05). This study suggests that fermented LM have an obvious potential to substantially replace 75% FM protein in the diets of barramundi.     

What controls fish functional diversity patterns in Colombian Andean streams?

Understanding the mechanisms that structure communities have been a major challenge in ecological theory. Functional trait-based approaches are increasingly used for studying the processes underlying community assembly. However, species-poor systems of Andean streams these processes are largely unknown. Tropical Andean streams are highly variable in space-time and characterised by the harsh or stable environment, resulting in a high taxonomic and ecological diversity. In this study, we tested the influence of environmental variables on the fish functional structure. We proposed that in ecosystems with harsh environments, environmental filtering will structure fish assemblages, and in ecosystems with a more stable environment, limiting similarity will prevail, increasing functional diversity. We analysed fish assemblages using functional diversity indices, fourth-corner RLQ analyses and multiple regression models. Environmental variables such as altitude, stream width, sub-Andean vegetation and pH influenced functional diversity. For instance, high values of functional redundancy were registered at high elevation streams, reflecting fish assemblages composed of highly dominant species with similar functional traits such as species of the genus Astroblepus. However, we found differences between Astroblepus species in the number and distance of gill rakers which might indicate resource partitioning and coexistence. On the other hand, our results show both stochastic dynamics and environmental filtering are structuring fish assemblages in low and high elevation Andean streams respectively.