Estimating Amino Acid Requirement of Brazilian Freshwater Fish from Muscle Amino Acid Profile

Information on nutritional requirement of some Brazilian farmed fish species, especially essential amino acids (EAA) requirements, is scarce. The estimation of amino acids requirements based on amino acid composition of fish is a fast and reliable alternative. Matrinxa, Brycon amazonicus, and curimbata, Prochilodus lineatus, are two important Brazilian fish with potential for aquaculture. The objective of the present study was to estimate amino acid requirements of these species and analyze similarities among amino acid composition of different fish species by cluster analysis. To estimate amino acid requirement, the following formula was used: amino acid requirement = [(amount of an individual amino acid in fish muscle tissue) × (average totalEAA requirement among channel catfish, Ictalurus punctatus, Nile tilapia, Oreochromis niloticus, and common carp, Cyprinus carpio)]/(average fish muscle totalEAA). Most values found lie within the range of requirements determined for other omnivorous fish species, in exception of leucine requirement estimated for both species, and arginine requirement estimated for matrinxa alone. Rather than writing off the need for regular dose–response assays under the ideal protein concept to determine EAA requirements of curimbata and matrinxa, results set solid base for the study of tropical species dietary amino acids requirements.     

Evaluation of practical diets containing different protein levels on gonad development of female redclaw crayfish Cherax quadricarinatus

The effect of five experimental diets with different crude protein content (220, 270, 330, 390 and 450 g kg⁻¹) on gonad development of female Cherax quadricarinatus was tested under laboratory conditions. After 70 days, a significant linear relationship indicated that higher concentrations of protein and carbohydrates in the hepatopancreas were produced as the dietary crude protein increased ( P  < 0.05). There were significant responses of the gonadosomatic index, hepatosomatic index, biochemical composition of the gonad (protein, lipids, carbohydrates and energy) and frequency of secondary vitellogenic oocytes to dietary protein level, as indicated by significant fits of the quadratic equation to the observed experimental data. The optimal response of the criteria parameters corresponded to levels of crude protein in the range 284–355 g kg⁻¹. Overall, 330 g kg⁻¹ crude protein with a protein : energy ratio of 15.6 mg kJ^–1 was considered the most adequate concentration of dietary protein for gonad development and biochemical composition in female redclaw crayfish.     

Environmentally friendly methods for controlling pine pitch canker

Fusarium circinatum is a highly virulent invasive pathogen that causes the disease commonly known as pine pitch canker (PPC). On mature trees, the most common symptoms of PPC include resin bleeding, resinous cankers, wilting of needles and dieback. In nurseries the main symptoms are yellowish needles, and wilting of foliage and shoots. PPC is considered one of the most important diseases of conifers globally and at least 60 species of Pinus along with Pseudotsuga menziesii are known to be susceptible. Quarantine regulations are crucial to minimize the risk of new introductions into disease-free countries. However, if these measures fail, implementation of environmentally friendly control methods is currently encouraged in an integrated management approach that minimizes the use of chemicals in forests. This review therefore summarizes current knowledge of biological control using endophytic fungi, bacteria and viruses, and other environmentally friendly methods to control PPC, including thermotherapy, natural products with fungicidal effects, promoters of innate host resistance mechanisms and breeding for resistance. Key research gaps to be addressed for improvement of effective management of this disease are discussed.     

Functionality of Agave Bagasse as Supplement for the Development of Prebiotics-Enriched Foods

Plant Foods for Human Nutrition - Agave bagasse is a fibrous-like material obtained during aguamiel extraction, which is also in contact with indigenous microbiota of agave plant during aguamiel...     

First report of rhizopus soft rot on soursop (Annona muricata) caused by Rhizopus oryzae in México

Journal of Plant Diseases and Protection - The soursop (Annona muricata) is an important tropical plant in the Pacific and Gulf region of México. In a farmer plantation during May, severe soft...     

An effective field screening method for flood tolerance in soybean

Flooding is an abiotic stress that causes considerable reductions in crop growth and yield worldwide. Soybean (Glycine max [L.] Merr.) cultivars are generally sensitive to flooding stress. The objective of this study was to develop an effective flooding tolerance screening method in the field. A total of 40 soybean genotypes were evaluated for flooding tolerance at V5 and R1 growth stages. At each stage, genotypes were exposed to different durations of flooding stress (3, 6, 9, 12 and 15 days). Plant foliar damage score (FDS) and plant survival rate (PSR) were used as the indicators of flooding tolerance. Soybeans were more sensitive to flooding at R1 growth stage than V5 growth stage. Length of flooding duration accounted for the variance of FDS and PSR. Soybean genotypes exposed to a 3‐day flooding in either V5 or R1 growth stage, did not show obvious foliar damage, while genotypes exposed to a 12‐ or 15‐day flooding showed significant foliar damage and plant death. The optimum flooding duration to screen for flooding tolerance in the field was determined to be 9 and 6 days for V5 and R1 growth stages, respectively, as distinguishable responses to flooding allowed genotypes to be classified as either being flooding tolerant or flooding sensitive. High correlation between FDS and PSR (.99, p < .0001) was observed. Similarly, FDS and PSR were highly correlated with grain yield (.95 and .95, p < .0001). The field screening method for flooding tolerance developed in our study will be favourable for selection of soybean flooding‐tolerant germplasm.     

Climate,oceanography, and recruitment: the case of the Bay of Biscay anchovy (Engraulis encrasicolus)

The Bay of Biscay anchovy has experienced, since 2001, a succession of low recruitments, resulting in the collapse of the stock in 2005; this has led to successive closures of the fishery. This study investigates the possible impact of different controlling factors [North Atlantic Oscillation (NAO), East Atlantic (EA) pattern, turbulence, upwelling, and river flow] upon anchovy recruitment and fishery catches. Fifty‐five percent of the recruitment variability of this fishery can be explained by upwelling over the spawning area; this is related, in turn, to the EA pattern. The conceptual understanding of the system proposed for the Bay of Biscay anchovy suggests that negative EA periods are associated with northeasterly wind circulation, which produces weak upwelling over the continental shelf. This pattern results in hydrodynamic stability over the area, leading, probably, to adequate food availability. A positive EA (which extends onwards, from 1998) is associated with southwesterly winds and downwelling over the continental shelf; this leads, probably, to the dispersion of anchovy food and larvae, together with increasing mortality.