Comparative Characterization of Enzymatic Digestion from Fish and Soybean Meal from Simulated Digestive Process of Pacific Bluefin Tuna,Thunnus orientalis

The digestive process of the Pacific bluefin tuna (PBT), Thunnus orientalis, was simulated through two phases of in vitro digestion: acidic digestion with porcine pepsin, followed by alkaline digestion with pancreatic crude extract (PCE) obtained from the PBT to hydrolyze fish meal (FM) and soybean meal (SBM) as protein substrates. The crude protein from FM resulted in a lower degree of hydrolysis (73.3%) compared with SBM (79.2%). However, the resulting digested products showed that FM contained 35% more small peptides, with sizes <6.5 kDa than those from the starting material (>150 kDa). The SBM had an increase of only 1.3% in the similar peptide cut‐offs found after hydrolysis. These results suggested that FM appeared to be a better source of protein according to the amount of low‐molecular weight peptides. In addition, the proteolytic activity of PCE showed that 88.9% of its alkaline proteolytic activity corresponded to trypsin and 2.9% corresponded to chymotrypsin activity. The results shown here demonstrate that peptide sizes are important in identifying suitable protein sources for aquafeed production to reinforce the primary results obtained from the in vitro digestibility using the pH‐Stat system. These results also contribute to a better understanding of the digestibility process in aquatic organisms.     

Effect of dietary protein:energy ratio on intake, growth and metabolism of juvenile green abalone Haliotis fulgens

Juvenile green abalone Haliotis rufescens were grown under laboratory conditions at 21±1 °C and fed formulated diets consisting of different protein:energy ratios (mg protein/kcal), 62, 74, 85, 100, 108, for 60 days. The level of crude protein ranged from approximately 26% to 44% while the energy content remained constant at about 4.1 kcal g⁻¹. Growth ranged from 3.63 to 12.33 mg day⁻¹. The growth of abalone fed the 100 and 108 diets was significantly greater than that of each of the other diets. Protein efficiency ratio increased as the dietary protein content increased except for the T108 diet (44% crude protein). Abalone apparently consume food to satisfy an energy requirement. Caloric expenditure due to metabolism was estimated for abalone fed diets with protein ratios of 62, 85, 100. Energy loss due to respiration did not vary appreciably among abalone fed the different diets. The proportional distribution of dietary energy into fecal, digestible, growth, and metabolic energy was estimated for abalone fed these diets. Apparent dry matter digestibility was among the lowest for abalone fed the 100 P:E diet, but growth of abalone fed this diet was significantly higher than that of each of the other treatments except the 108 diet. Unexplained energy loss to achieve balance ranged from 7% to 28.5%, some of which is probably due to differential mucus and ammonia production. Results suggest a potential for the reduction of both dietary protein and lipid without causing any adverse effects on the growth response.     

Fall Armyworm Damaged Maize Plant Identification using Digital Images

The objectives of precision agriculture are profit maximisation, agricultural input rationalisation and environmental damage reduction, by adjusting the agricultural practices to the site demands. The fall armyworm (Spodoptera frugiperda) is one of the most important maize pests in Brazil and the use of insecticide is the main control method. It is believed that site-specific control can be implemented by using a machine vision system. The objective of this work was to develop and evaluate an algorithm at simplified lighting conditions for identifying damaged maize plants by the fall armyworm using digital colour images. Images of damaged and non-damaged maize plants were taken in eight different stages and in three different light intensities. The proposed algorithm had two stages: the processing and the image analysis. During the first stage, the images were processed to create binary images where the leaves were segmented from the other pixels. At the second stage, the images were subdivided into blocks and classified as ‘damaged’ or ‘non-damaged’ depending on the number of objects found in each block. The algorithm correctly classified 94·72% of 720 images.     

Glyphosate injury on Cyperus esculent us leaves and basal bulbs: histological study

The effect of glyphosate on leaves and basal bulbs of yellow nutsedge (Cyperus esculentus L.) plants was studied. Treatment with glyphosate did not affect leaf anatomy, although light necrotic spots were seen on the veins. In contrast, basal bulb organization was greatly affected with large necrotic zones and disorganization in the vascular cylinder due to herbicide accumulation. Depletion or disappearance of vacuolar phenols was observed in bulbs of plants treated with the highest doses of glyphosate. The most remarkable effect of glyphosate was the appearance of one layer of sclerenchymatic cells between root and rhizome primordia and the cortical tissues which could play an important role in the inhibition of rhizome and root emergence by the herbicide.     

Effect of Breeding Activity on the Microflora of the External Genitalia and in the Semen of Stallions,and the Relationship Between Micro‐organisms on the Skin and on the External Genitalia

A possible role of breeding activities in the composition of the microbial population in stallions' external genitalia (EG) and the relationship between micro‐organisms colonizing the skin of the abdomen and the ones colonizing the EG have not been studied. In experiment 1, EG microbiological samples were collected from 41 stallions used for both natural cover and semen collection (BST) and from 18 non‐breeding stallions (NBST). A higher (p < 0.05) frequency of isolation of potentially pathogenic species was found for BST. Age did not influence number of micro‐organism species isolated both in BST and NBST. In experiment 2, the microbial content of the EG and semen was compared in 23 BST. Most micro‐organisms isolated from the EG were present in semen, albeit with a numerically lower prevalence. In 7 stallions, six microbial species isolated from semen were absent from the EG cultures, suggesting contamination by the operator. In experiment 3, a numerically higher number of micro‐organism species was isolated from the EG of 31 stallions, than from their skin of the ventral abdomen in contact with the penis or from the skin of the thorax. With the sole exception of Escherichia coli, potentially pathogenic bacteria were only isolated from the EG but not from the skin. Results suggest that breeding activity increased the number of species colonizing the EG; most species isolated from the EG were also found in semen even if with a lower frequency, and additional semen contamination seemed to occur during its manipulation. Many micro‐organism species of the skin were also isolated from the penis, but independently of being or not in contact with the penis, skin did not seem to provide an adequate environment for the growth of potentially pathogenic bacteria that were isolated from EG, with the sole exception for E. coli.     

Changes in productivity and profitability of wool-growing farms that follow recommendations from agricultural and veterinary studies

Objective To estimate the changes in productivity and profitability in a group of wool-growing farms as they adopted major recommendations from agricultural and veterinary studies.
Farms Four wool-growing farms in south western Victoria were selected from the clients of the Mackinnon Project, a farm consultancy service run from the University of Melbourne. Each farm had closely followed recommended procedures, kept comprehensive financial and physical records and had been clients for at least 5 years. The comparison group was the South Western Victoria Monitor Farm Project (SWVMFP), about 45 farms in the same region as the study farms that were monitored annually by Agriculture Victoria.
Procedure For a 7-year period, the financial and physical performance of both groups of farms was estimated. Stocking rate, wool production, gross farm income, farm operating costs, net farm income and return on assets were compared.
Results Mean gross farm income of the four study farms steadily rose from 86% of the average SWVMFP farm before the adoption of recommendations to an average of 155%. During the same period, net farm income rose from 70% to 207% of the average of the SWVMFP. Return on asset of the four farms rose irregularly from 26% to 145% of the average of the SWVMFP. Farm operating costs on the four farms were higher than for the SWVMFP group, but the ratio of costs remained relatively constant.
Conclusion The adoption of proven research results was associated with large increases in net farm income. An increase in gross income, rather than a reduction in costs was the main reason for this. Research results offer a way to increase the financial viability of wool-growing farmers, many of whom are currently unable to maintain their lifestyle, resources and infrastructure.     

Hanbury Brown Twiss effect for ultracold quantum gases

We have studied two-body correlations of atoms in an expanding cloud above and below the Bose-Einstein condensation threshold. The observed correlation function for a thermal cloud shows a bunching behavior, whereas the correlation is flat for a coherent sample. These quantum correlations are the atomic analog of the Hanbury Brown Twiss effect. We observed the effect in three dimensions and studied its dependence on cloud size.     

Effect of ensiled hop (Humulus lupulus L.) residues on plasma acetate turnover rate in sheep

An isotope dilution method using [1‐¹³C]sodium acetate was applied to determine the effect of feeding ensiled hop (Humulus lupulus L.) residues on plasma acetate turnover rate in six adult crossbred sheep. The sheep were fed 63 g/kg body weight (BW)^0.75/day of either mixed hay of orchardgrass (Dactylis glomerata L.) and reed canarygrass (Phalaris arundinacea L.) and round bale silage at 3:1 ratio (Hay‐diet), or another where round bale silage was replaced by ensiled hop residues (Hop‐diet) with a crossover design each of a 3‐week period. The isotope dilution method was performed on day 21 of each dietary treatment. Dry matter digestibility was similar between diets, and nitrogen (N) digestibility was lower (P = 0.001) for Hop‐diet than Hay‐diet. However, N retention did not differ between diets. Plasma acetate concentration was lower (P = 0.04) for Hop‐diet than Hay‐diet, and the turnover rate of plasma acetate did not differ between diets. Plasma concentration of lactate and non‐esterified fatty acids were similar between diets. Hop‐diet was found almost comparable to Hay‐diet on plasma acetate turnover rate in the present experimental conditions. Therefore, it could be concluded that hop residues partially could be used as an alternative to traditionally used round bale silage for rearing sheep.     

Follow-up of mercury levels in fish,human hair and urine in the Madeira and Tapajós basins,Amazon, Brazil

Informal economy of gold mining has contaminated some important river basins in Amazon. Follow-up studies on critical compartments showed some areas with high Hg levels in fish as well as in human hair samples. Average Hg in piscivorous fish in the Madeira river itself was 846 ppb (N=284) with a maximum of 3921 ppb. Mercury in fish from non polluted areas in this basin shows high variability, even for single species. A seasonal variation in Hg content was observed, with higher values at the end of the dry season. In the upper Tapajós basin comparable values were found for fish but with a definite decreasing trend downstream. Average value for piscivorous fish in the whole Tapajós basin is 482 ppb (N=122) with a maximum value of 3770 ppb. Hair Hg was higher in fishing villages in the Tapajós (average: 17 ppm; with N=432 and maximum value of 176 ppm) than in the Madeira (average: 9 ppm; N=169; maximum 71 ppm), and data from some areas of the Tapajós suggest a decrease with time. Mercury was much higher in urine of goldshop workers in Santarém (low Tapajós) than in Alta Floresta (high Tapajbs) and show a decreasing trend in both cases, probably related to the significant decline in gold mining activities during the study period (1986–1994).