Risk factors associated with Mycoplasma capricolum subspecies capripneumoniae and morbillivirus infection in small ruminants in Tanzania

Tropical Animal Health and Production - Mortality of domestic small ruminants caused by contagious caprine pleuropneumonia (CCPP) and Peste des petits ruminants (PPR) is frequently reported in...     

Variation in seed protein digestion of different pea (Pisum sativum L.) genotypes by cecectomized broiler chickens: 1. Endogenous amino acid losses, true digestibility and in vitro hydrolysis of proteins

The aim of this study was to investigate the cause of variation in the digestibility of pea protein in poultry and to find a tool to select genotypes with high digestibility potential by using an in vitro hydrolysis assay. Eight pea genotypes were selected for their difference in seed protein content and composition. To reduce the variation due to tannins and particle size, seeds from these 8 genotypes were dehulled and micro-ground. They were incorporated as the only protein source in 8 different experimental isoproteinaceous diets with similar metabolisable energy content. The amino acid digestibility was studied in cecectomized chickens. A balance method was used to obtain apparent digestibility, and the isotope dilution technique was used to determine endogenous losses and true digestibility, after feeding a double labelled test meal containing chromic oxide and ¹⁵N-labelled peas. The 8 diets showed differences in apparent amino acid digestibility. The average apparent digestibility for all amino acids varied between 79.5 and 86.3%, with the highest values for arginine (85.2 to 90.8%) and glutamic acid (85.2 to 90.5%), and the lowest values for cystine (63.3 to 69.7%) and tryptophan (69.1 to 80.3%). This variability of apparent amino acid digestibility was due to variations in endogenous losses and true digestibility among the 8 pea genotypes. The average endogenous losses as determined for 9 amino acids ranged from 3.6 to 5.4% of ingested amino acids, with the highest value for threonine (8.0 to 11.0%). The average true digestibility varied between 84.4 and 90.2%, with the highest values for lysine (89.0 to 95.0%), and the lowest for isoleucine (81.0 to 88.7%) and valine (82.4 to 88.7%). In vitro hydrolysis of protein from micro-ground seeds was performed for the 8 pea genotypes using three proteases (pepsin, trypsin and chymotrypsin). The quantity of small peptides (< 3 kDa) that appeared after the combined hydrolysis with pepsin (3 h) followed by trypsin and chymotrypsin (15 min) was significantly correlated with the average true digestibility of the 8 genotypes (R = 0.74; P < 0.05).     

Karyotype analysis of interspecific hybrids between Haliotis rufescens and Haliotis discus HANNAI

Evidence of hybridization in Haliotis has been mainly supported by hatchery experiences and collection of wild hybrid abalones among several species from natural populations worldwide. However, despite the importance to understand the role of the hybridization process through Haliotidae evolution, and also its impact on the abalone aquaculture, genetic studies in hybrid abalones have been poorly developed. Herein, cytogenetic approach allows studying the genetic conformation in hybrid organisms at the chromosome level. This paper reports a quantitative karyotype analysis in Haliotis rufescens, Haliotis discus hannai and their interspecific hybrid. Thus, to characterize chromosome pairs and establish cytogenetic comparisons, chromosome banding with distamycin‐A/4,6‐diamidino‐2‐phenylindole fluorochromes and morphologic measurements were performed. The results showed that the hybrids are successfully viable and their karyotypes evidenced a conservative chromosome number of 2n=36. The karyo‐idiogram showed a high correspondence in chromosome pair morphology among the hybrids and their parental species, except for a single heteromorphic pair that corresponds to the chromosome 16 from H. rufescens andH. d. hannai respectively. The implications of the abalone hybrid viability derived from its chromosome composition are discussed.     

Aluminium chloride‐induced toxicity in zebrafish larvae

Embryos at shield stage and larvae at protruding mouth stage were exposed to different concentrations of aluminium chloride (AlCl₃) for 72 h with the purpose to analyse their phenotype and lethality. After 24, 48 and 72 h of treatment, higher toxicity of the metal was observed on larvae with minimal lethal concentration of 0.25, 0.20 and 0.08 mm , respectively, while for embryos the corresponding values were 40, 25 and 16 mm . We observed pericardial oedema and alteration of heart rate in 50% of larvae after 48 h of exposure to 100 μm . In larvae exposed to the same concentration, there was also a neurological injury at the level of glial cells, with the number of glial fibrillary acidic protein‐positive cells being significantly reduced. This study confirms the toxic nature of this metal and shows that aluminium could also interestingly represent a cardiotoxin in addition to its neurotoxic ability.     

Effects of biofloc technology on reproduction and ovarian recrudescence in Nile tilapia

The objectives of this study were to evaluate the reproductive cycle, morphological changes of ovary and mobilization of energy reserves in Nile tilapia reared with biofloc technology (BFT). In general, the growth and reproductive performance were highly similar between BFT and Control system (clear water). Difference between the systems was found in the hepatosomatic index (using mixed‐effects models), which suggested that BFT can alter the energy mobilization in the post‐spawning period. The absolute and relative fecundity, fertilization rate, number of larvae produced per female, gonadosomatic index, proportion of oogenesis cells, number of post‐ovulatory and atretic follicles were similar between the two systems. We also did not detect a reduction in the reproductive cycle length in Nile tilapia reared in BFT. Because there was no evidence of the negative effects of BFT on Nile tilapia reproduction, we concluded that BFT might be used for breeder stocking of this species.     

Dietary organic acids blend alone or in combination with an essential oil on the survival,growth, gut/liver structure and de hemato‐immunological in Nile tilapia Oreochromis niloticus

This study evaluated the effects of dietary supplementation of organic acids blend (OAB) alone or in combination with essential oil, Lippia origanoides (OAE) for Nile tilapia fed supplemented diets for 30 days. Fish (1.1 ± 0.04 g) were fed control (Control), or OAB 0.5% or OAB 0.5% + essential oil 0.125% (OAE) respectively. At the end of the experiment, samples were collected for de hemato‐immunological, histological analysis of the intestine and liver, as well as microbiology of the intestine. The pH of the diets supplemented with OAB and OAE reduced 0.92 and 0.19 respectively. The growth and FCR were unaffected by the treatments, but survival was significantly higher in the OAB treatment. Fish fed the OAB diet showed reduced concentration of total heterotrophic bacteria and Pseudomonas sp. in the intestine. Increased glucose in fish fed OAB and high number of circulating monocytes in fish fed OAE diet were observed. The anterior intestine of fish fed OAE diet showed larger number of goblet cells and increased villi height. The diet supplemented with OAB, mainly, improved the intestinal health and survival of tilapia juveniles and can be used in juvenile production.     

The use of infrared spectroscopy and machine learning tools for detection of Meloidogyne infestations

Plant parasitic nematodes are generally soilborne pathogens that attack plants and cause economic losses in many crops. The infested plants show nonspecific symptoms or, often, are symptomless; therefore, diagnosis is performed by taking soil and root tissue samples. Here, we show that a combination of different infrared spectra analysis and machine learning algorithms can be used to detect plant parasitic nematode infestations before symptoms become visible, using leaves instead of roots and soil as samples. We found that tomato and guava plants infested with Meloidogyne enterorlobii produced different spectral patterns compared to uninfested plants. Using partial spectra from 1,450 to 900/cm as the "fingerprint region", principal component analyses indicated that after 5 (tomatoes) or 8 weeks (guava), plants with no visible symptoms of infestations were positively diagnosed. To improve the early detection response, we used machine learning modelling. A support vector machine (SVM) was used to obtain more robust, accurate models. The SVM model contained 34 support vectors, 17 for each level. The overall performance of the model was >97% and the total accuracy was significantly higher, demonstrating the absence of chance prediction. The best prediction of infestation was obtained at the second and fourth weeks for tomatoes and guavas, respectively, reducing the diagnostic time by half. The combined application of these techniques reduces the processing time from field to laboratory and shows enormous advantages by avoiding root and soil sampling.     

Chocolate is a powerful ex vivo and in vivo antioxidant, an antiatherosclerotic agent in an animal model, and a significant contributor to antioxidants in the European and American Diets

Chocolate today is often viewed as a food or snack with little nutritional value. The high saturated fat content of chocolate has also contributed to the belief that its consumption increases the risk of heart disease. However, recent human studies have proven that chocolate has beneficial effects on some pathogenic mechanisms of heart disease such as endothelial function and blood pressure. Although the antioxidant properties of chocolate have been known for some time, there has been no examination of its place in the U.S. diet as a source of antioxidants. This paper demonstrates that chocolate makes a significant contribution to U.S. per capita dietary antioxidants and by inference the European Community's. In the U.S. diet chocolate is the third highest daily per capita antioxidant source. An ex vivo study shows that epicatechin, a major polyphenol in chocolate and chocolate extracts, is a powerful inhibitor of plasma lipid oxidation due to polyphenols' ability to bind to lower density lipoproteins. Conversely, the fat from chocolate alone is a pro-oxidant in this model. This is also demonstrated in an in vivo human study. After consumption of dark chocolate and cocoa powder, the lower density lipoproteins isolated from plasma were protected from oxidation compared to the lipoproteins isolated after cocoa butter consumption, which were put under oxidative stress. In an animal model of atherosclerosis, cocoa powder at a human dose equivalent of two dark chocolate bars per day significantly inhibited atherosclerosis, lowered cholesterol, low-density lipoprotein, and triglycerides, raised high-density lipoprotein, and protected the lower density lipoproteins from oxidation. Chocolate has thus been shown to have potential beneficial effects with respect to heart disease.     

Small Area Estimation of Proportions with Constraint for National Resources Inventory Survey

Motivated by the need to produce small area estimates for the National Resources Inventory survey, we develop a spatial hierarchical model based on the generalized Dirichlet distribution to construct small area estimators of compositional proportions in several mutually exclusive and exhaustive landcover categories. At the observation level, the standard design-based estimators of the proportions are assumed to follow the generalized Dirichlet distribution. After proper transformation of the design-based estimators, beta regression is applicable. We consider a logit mixed model for the expectation of the beta distribution, which incorporates covariates through fixed effects and spatial effect through a conditionally autoregressive process. In a design-based evaluation study, the proposed model-based estimators are shown to have smaller root-mean-square error and relative root-mean-square error than design-based estimators and multinomial model-based estimators. Supplementary materials accompanying this paper appear online.