Enrichment of Food Mixtures with Essential Fatty Acids and Calcium from Nile Tilapia By-Products

ABSTRACT

This work aimed at increasing the content of calcium and the quality of fatty acid composition of food mixtures developed with by-products from Nile tilapia fed with flaxseed. Mixes using cassava flour and by-products were submitted to analyses of proximate composition, fatty acids and minerals quantification, and sensory assessment. The lipid and protein fractions were higher for the mix containing 30% addition of fish meal. There was an incorporation effect of essential fatty acids in the mix of flours containing fish fed with flaxseed. Calcium had the highest concentration among minerals. Sensory acceptance range was 55–65% for formulations with fish by-products.     

Morphological and physiological responses and the recovery ability of Paspalum accessions to water deficit and waterlogging

Limited knowledge about the agronomic potential of Paspalum species from the Americas hinders their use in pastures. The response mechanisms to water deficit and waterlogging were studied in five accessions of Paspalum sp. (P. regnellii cv. BRS Guará and BGP 397, P. conspersum BGP 402 and P. malacophyllum BGP 289 and BGP 293) and Urochloa brizantha cv. Marandu. Morphological and physiological traits at the end of the stress and after the recovery period were measured. All Paspalum accessions, especially BGP 289, BGP 402 and BGP 397, and also cv. Marandu, showed survival mechanisms to water deficit. BRS Guará showed adaptive features to waterlogging, although had with a low survival rate to water deficit. Under waterlogging, BGP 289 and cv. Marandu showed reduced growth, and after the recovery period, they presented low plant survival and root recovery. Although growth of BGP 293 was reduced during waterlogging, it presented high tiller survival rate. BGP 293, BGP 402 and BGP 397 showed adaptive potential strategies for waterlogging and water deficit. There is genetic variability among the evaluated accessions for water deficit and waterlogging stresses, suggesting that they may be used per se or as progenitors in crosses with other genotypes in breeding programmes.     

Selection of cassava accessions with multiple resistance to pathogens associated with root rot disease

Cassava root rot disease (CRRD) severely affects productivity in several countries. The objective of this study was to estimate genetic parameters and to identify multiple resistance sources against pathogens associated with CRRD. The symptoms caused by Fusarium spp., Phytophthora spp., and Botryosphaeriaceae species in peel and pulp from the roots were evaluated in 277 accessions using a whole tuberous root inoculation method. The resistance data were obtained by REML/BLUP (restricted maximum likelihood/best linear unbiased predictor). The classic selection index (CI), multiplicative (MI), and sum of ranks (SRI) were used to identify the accessions with multiple resistance. For all pathogens, the environmental variance (\(\sigma_{e}^{2}\)) was the most important component. Individual heritability \(\left( {h_{g}^{2} } \right)\) was of low magnitude for resistance to most pathogens (0.16 ± 0.02—peel and 0.31 ± 0.03—pulp for Fusarium spp.; 0.26 ± 0.03—peel and 0.30 ± 0.03—pulp for Phytophthora spp.; and 0.28 ± 0.03—peel and 0.27 ± 0.03—pulp for Botryosphaereacea species). The distribution of CRRD symptoms indicated the presence of quantitative inheritance. The direct selection of the 15 more resistant accessions based on the genotypic predicted values result in high reductions of disease (>50%). However, there was a low matching rate of the most resistant accessions for each pathogen and the different parts of the tuberous roots (peel and pulp). The CI and MI were the most promising compared to the SRI to ensure high and balanced resistance for each pathogen. Understanding the genetic basis of resistance to CRRD and the identification of sources with multiple resistance may be useful in various management strategies to control the disease.     

Detection of rubber tree orchards infested by Meloidogyne exigua using vegetation indexes obtained from satellite images

New Forests - Hevea brasiliensis natural rubber production is strategic for the world economy. Meloidogyne exigua causes the main root disease in this crop in Brazil. Its early diagnosis allows...     

Trophic ecology of speckled peacock bass Cichla temensis Humboldt 1821 in the middle Negro River,Amazon, Brazil

The aim of this study was to analyse the trophic ecology of speckled peacock bass Cichla temensis inhabiting two tributaries of the middle Negro River, the Aracá River and the Demeni River. Using an analysis of stomach contents and stable isotope composition (δ¹⁵N, δ¹³C) of scales, we describe the diet and evaluate the trophic position of subadult and adult individuals. We then test whether diet shifts and trophic positions occurred among successive size classes and among sample locations. The stomach content analysis confirmed the piscivorous feeding habit of the species and showed that the speckled peacock bass preyed on a variety species belonging to different trophic guilds. The length of the ingested prey increased with the size of the speckled peacock bass. Diet composition and trophic position were not different among size classes. δ¹³C values yielded significant shifts among the size classes: larger individuals displayed higher δ¹³C values than smaller individuals. Trophic position varied between locations, with lowest values observed in fish from the Aracá River. This study demonstrated that diet of C. temensis may vary according to the size of the fish, even at the subadult or adult stages, and according to the river/locality, even within a same basin. We then suggest that further studies take into account local availability of food resources to better explore C. temensis diet and tropic ecology.     

Tibiotarsus bone characteristics and tibial dyschondroplasia incidence of broilers fed diets supplemented with leucine and valine

Two experiments were conducted to study the effect of standardized ileal digestible (SID) leucine and valine levels on tibiotarsus bone characteristics and the incidence of tibial dyschondroplasia of broilers from day 1 to 21 (Experiment I) and day 21 to 42 post‐hatch (Experiment II). Each experimental phase was evaluated independently. In both experiments, a total of 1,500 one‐day‐old Cobb 500 male broiler chickens were distributed in a completely randomized design 5 × 5 factorial arrangement for a total of 25 treatments. The SID leucine and valine levels were ranged from 10.0 to 19.6 g/kg, and 6.0 to 12.0 g/kg from day 1 to 21 post‐hatch, respectively, while day 21 to 42 post‐hatch ranged from 10.0 to 18.0 g leucine/kg, and 5.2 to 11.2 g valine/kg. Serum calcium and phosphorus, bone concentrations of calcium, phosphorus and ash, diameter and Seedor index of the tibiotarsus were not affected (p > .05) by the treatments at 21 or 42 days of age. There was an interaction (p ≤.06) between the SID levels of leucine and valine on tibiotarsus breaking strength at 21 days, but not at 42 days of age (p > .05). Tibiotarsus breaking strength was maximized in broilers from day 1 to 21 with the dietary levels of leucine and valine at 14.2 and 9.0 g/kg respectively. Dietary leucine levels reduced linearly (p < .05) the hypertrophic zone of tibiotarsus cartilage at 21 days of age. Therefore, leucine and valine supplementation interact positively on bone strength of broilers from day 1 to 21 post‐hatch. Leucine can be a useful amino acid for reducing the hypertrophic cartilage zone in broilers from day 1 to 21, but not from day 21 to 42 post‐hatch.     

Total tract nutrient digestion and milk fatty acid profile of dairy cows fed diets containing different levels of whole raw soya beans

Whole oilseeds such as soya beans have been utilized in dairy rations to supply additional fat and protein. However, antinutritional components contained in soya beans, such as trypsin inhibitors and haemagglutinins (lectins) may alter digestibility of nutrients and consequently affect animal performance. The objective of the present experiment was to quantify the effect of different levels of whole raw soya beans in diets of dairy cows on nutrient intake, total tract digestion, nutrient balances and milk yield and composition. Sixteen mid to late‐lactation cows (228 ± 20 days in milk; mean ± SD) were used in four replicated 4 × 4 Latin square design experiment with 21‐d periods. Cows were assigned to each square according to milk yield and DIM. The animals were randomly allocated to treatments: control (without soya beans addition; CO), WS9, WS18 and WS27, with addition of 9%, 18% and 27% of whole raw soya bean in diet on a dry matter (DM) basis respectively. All diets contained identical forage and concentrate components and consisted of maize silage and concentrate based on ground corn and soya beans at a ratio of 60:40. There were no differences in OM, CP, NDF and NE_L intakes (kg/day and MJ/day) among the treatments (p > 0.05). However, DM and NFC intakes were negatively affected (p = 0.04 and p < 0.01, respectively) and ether extract (EE) intake was positively affected (p < 0.01). Total tract digestion increased linearly with whole raw soya beans for EE (p < 0.01) and NDF (p = 0.01). The excretion (kg/day) of digested soya beans grains increased linearly according to addition of whole raw soya beans. However, the nutritive characteristics of excreted grains were not altered. Milk (kg), milk lactose (kg) and protein (kg) yield decreased linearly (p < 0.01, p < 0.01 and p = 0.04, respectively) milk fat content (%) increased linearly (p < 0.01) with whole raw soya beans inclusion. Increasing addition of whole raw soya beans affected milk fatty acid profile with a linear decrease of cis‐9‐trans 11CLA and total saturated FA; and linear increase of total unsaturated and C_18:3 FA. Energy balance was positively affected (p = 0.03) by whole raw soya beans as well as efficiency of NEL milk/DE intake (p = 0.02). Nitrogen balance and microbial protein synthesis were not affected by whole raw soya beans. Increasing doses of whole raw soya beans decreased dry matter intake and milk yield, however, led to an increase of unsaturated acids in milk and higher milk fat concentration.     

The β‐amylase genes: negative regulators of disease resistance for Verticillium dahliae

Little is known about the role of plant primary metabolism in defence against pathogens. The present study is the first investigation published that examines the role of β‐amylase (BAM) genes upon fungal, Verticillium dahliae, infection. The responses of Arabidopsis thaliana plants impaired in BAM1, BAM2, BAM3, BAM4 genes, along with double, triple and quadruple mutants of those genes, were used to explore the involvement of BAM in the host plant–V. dahliae interaction. Less severe symptoms were recorded in bam mutants compared to wild type. Real‐time quantitative PCR (qPCR) revealed that the decrease in symptom severity shown in bam plants was correlated with reductions in the growth of the pathogen in the plants. Confocal microscopy of the most and least susceptible bam mutants and the wildtype plants showed that there were no differences between them in the number of attached conidia and penetration sites on the roots. BAM1, BAM2 and BAM3 expression was altered upon V. dahliae infection in the aerial tissues of the wild type. Analysis by qPCR of the PR1 and PDF1.2 expression in the bam3, bam1234, bam14 and wildtype plants showed that PR1 was up‐regulated in the roots of bam plants upon V. dahliae infection.     

Colletotrichum species causing grape ripe rot disease in Vitis labrusca and V. vinifera varieties in the highlands of southern Brazil

Ripe rot is one of the most important bunch diseases of grapes in the highlands of southern Brazil and a matter of concern for winegrowers. Sixty-one strains isolated from berries of Vitis labrusca and V. vinifera varieties with symptoms were classified by phylogenetic analysis of the sequences of β-tubulin, glyceraldehyde-3-phosphate dehydrogenase, D1/D2 domain of 28S rDNA, and rDNA internal transcribed spacer. They were also characterized by morphology, and their pathogenicity was evaluated. The combined molecular data allowed identification of six Colletotrichum species: C. fructicola, C. kahawae and C. viniferum (gloeosporioides complex), C. limitticola, C. nymphaeae (acutatum complex), and C. karstii (boninense complex). This is the first report of C. karstii and C. limitticola associated with the ripe rot of grapes. Morphological characteristics varied within and among species, confirming their separation at the complex level. Pathogenicity tests on V. vinifera berries showed that the most prevalent species, C. viniferum (37.8%) and C. fructicola (36.1%), were more virulent than the less prevalent species C. limitticola and C. karstii. Our findings indicate that there is a high diversity of Colletotrichum species associated with ripe rot disease of grapes in Brazil. There were no clear differences in the distribution of Colletotrichum species between V. labrusca and V. vinifera varieties. The determination of fungal species responsible for grape ripe rot in Brazilian vineyards may contribute to further epidemiological studies and the development of more efficient prophylactic methods for ripe rot management.