Intestinal development of bovine foetuses during gestation is affected by foetal sex and maternal nutrition

We aimed to evaluate the effects of maternal nutrition (MN) and foetal sex on the intestinal development of bovine foetuses throughout different days of gestation (DG). Forty‐four multiparous, dry Holstein × Gyr cows with average initial body weight of 480 ± 10 kg were fed the same diet of either restricted feeding at 1.15% of body weight (CO, n = 24) or fed ad libitum (overnourished, ON, n = 20). Six cows from CO group and five cows from ON group were slaughtered at 139, 199, 241 and 268 DG, and foetuses were necropsied to evaluate the intestinal development. The mass, length and density of foetal intestines were not affected by MN (p ≥ 0.260). An interaction between MN and DG was observed for the villi length of jejunum (p = 0.006) and ileum (p < 0.001). Villi length of jejunum and ileum was higher (p < 0.10) in foetuses from ON‐fed cows than in foetuses from CO‐fed cows at 139 DG. However, at 199 DG, the villi length of jejunum and ileum of foetuses from CO‐fed cows was higher than in foetuses from ON‐fed cows. Despite these differences, MN did not affect the villi length of jejunum and ileum at 268 DG (p > 0.10). Female foetuses had greater small intestine mass (p = 0.093), large intestine mass (p = 0.022), small intestine mass in proportion to body mass (p = 0.017) and large intestine mass in proportion to body mass (p < 0.001) than male foetuses. Female foetuses had also longer small intestine (p = 0.077) and greater small intestine density (p = 0.021) and villi length of jejunum (p = 0.001) and ileum (p = 0.010) than males. We conclude that MN affects the pathway for the development of foetal villi length throughout the gestation in bovine foetuses without changing the final villi length. Female foetuses had higher intestinal mass, density and villi length than males during the foetal phase in bovines.     

Genetic diversity in Fusarium oxysporum f. sp. melonis*

Fusarium oxysporum f. sp. melonis is an important vascular wilt pathogen of melon. Races 1, 2 and 1–2 of this fungus have been identified in Portugal by pathogenicity tests with appropriate hosts. The aim of this research was to examine the relationships between different races of F. o. melonis of Portuguese and French origin through analysis of random amplified polymorphic DNAs (RAPDs). DNA fingerprint profiles were developed for all the accessions. Each isolate showed 5–10 DNA bands with each of the 16 primers employed. A total of 126 bands was obtained. The size of amplified DNA fragments generated with these primers ranged from 0.5 to 3.2 kb. A phenogram based on the Jaccard coefficient of similarity was computed by the unweighed pair group method using arithmetic averages (UPGMA). It was found that Portuguese race 2 is very similar to French race 1, while French race 2 is the most dissimilar being clearly separated from all other races. The genetic diversity of these isolates is also being studied for vegetative compatibility by using the nit mutant system.     

Fusarium oxysporum Fo47 confers protection to pepper plants against Verticillium dahliae and Phytophthora capsici,and induces the expression of defence genes

The application of the nonpathogenic isolate Fusarium oxysporum 47 (Fo47) reduced the symptoms of verticillium wilt, phytophthora root rot and phytophthora blight in pepper plants. Botrytis cinerea was also tested on the leaves of plants treated with Fo47, but no protection was observed. Verticillium dahliae colonies cultured in the presence of Fo47 grew slower than control cultures, but Phytophthora capsici growth was unaffected by Fo47. At least part of the protection effect observed against V. dahliae could therefore be due to antagonism or competition. In order to search for induced resistance mechanisms, three defence genes previously related to pepper resistance were monitored over time. These genes encode a basic PR‐1 protein (CABPR1), a class II chitinase (CACHI2) and a sesquiterpene cyclase (CASC1) involved in the synthesis of capsidiol, a phytoalexin. These three genes were transiently up‐regulated in the roots by Fo47 in the absence of inoculation with the pathogen, but in the stem only CABPR1 was up‐regulated. In plants that were inoculated with V. dahliae after the Fo47 treatment, the three genes had a higher relative expression level than the control in both the roots and the stem.     

Phenotypic and genetic variability of fungal isolates associated with the Septoria leaf spot disease of lettuce (Lactuca sativa) in Brazil

Journal of Plant Diseases and Protection - Septoria leaf spot is a severe disease of lettuce in tropical and subtropical regions, inducing yield/quality losses and increasing production costs....     

Applying ecological knowledge to decisions about seed tree retention in selective logging in tropical forests

In production forests in the moist tropics, trees are selected for felling or retention primarily by species and size. Tree regeneration requirements and forest stand responses to harvesting are often ignored, and consequently, the regeneration of the residual forest is not ensured. We developed and tested an alternative approach to tree selection, where seed trees were retained as a proportion of harvestable trees, with the proportion defined as a function of species’ ecological attributes and local abundance (100 ha), in contrast to the conventional approach which retained 10% of harvestable trees, uniformly across commercial species at the compartmental scale (1000 ha). The study was conducted in Democracia Project, a forest management operation in Amazonas, Brazil. The conventional approach failed to retain any seed trees at the 100 ha block scale for 7 of 37 commercial species, whereas the alternative approach retained a minimum number of seed trees per 100 ha block for all commercial species. The conventional approach resulted in the retention of relatively high proportions of potential seed trees for common species (e.g., 22% for Eperua oleifera and 36% for Maquira sclerophila) that are shade bearers and recruit readily at the site; alternately, for species with constraints to regeneration, it retained relatively low proportions (e.g., 2% for Dinizia excelsa and Hymenolobium nitidum). The alternative approach effectively retained lower proportions of common species (e.g., 10% for E. oleifera and 13% for M. sclerophila) and relatively high proportions of species with regeneration constraints (e.g., 20% for D. excelsa and 16% for H. nitidum). Our study demonstrates that it is feasible to implement at an operational scale, species-specific retention rules that take into account local abundance when inventory data are digitised and spatially explicit. Monitoring regeneration in the residual stands over time will provide the evidence to assess the ecological benefits of the adoption of our alternative approach.     

Replacement levels of elephant grass by moist pineapple by-product silage in diets of Santa Inês crossbred sheep: performance and digestibility

The present study evaluated the effect of replacing elephant grass (EG) with moist pineapple by-product silage (PS) on the apparent digestibility, consumption of digestible nutrients and performance of 25 castrated male lambs Santa Ines crossbreds. The lambs had an initial body weight of 20.2?±?3.5 kg and were housed in individual pens in a completely randomised design with five treatments (replacement of EG by PS at five proportions of 0, 25, 50, 75 and 100 %) and five replicates during 74 days. There was no significant effect of PS replacement proportions on the intake of dry matter (DM), organic matter (OM), total carbohydrates (TC), non-fibrous carbohydrates or total digestible nutrients (TDN). The consumption of crude protein (CP) decreased linearly with the inclusion of PS in the diets. The digestibility of DM, OM and TCs as well as levels of TDN increased linearly with the addition of PS. The use of PS in the diets had no significant effect on the digestibility of CP and neutral detergent fibre corrected for ashes and protein (NDFom(n)). These results demonstrated that there was no difference in the performance of animals fed diets with or without PS.     

Foetal development of skeletal muscle in bovines as a function of maternal nutrition,foetal sex and gestational age

To determine the effects of maternal nutrition on modifications of foetal development of the skeletal muscle and possible increase in the potential of skeletal muscle growth in cattle, gestating cows were either fed 190% NRC recommendations (overnourished; ON) or 100% NRC recommendation (control; CO). Interaction between maternal nutrition (MN) and the foetal sex (FS) was also investigated. Foetuses were necropsied at four different time points throughout gestation (139, 199, 241 and 268 days of gestation) to assess the mRNA expression of myogenic, adipogenic and fibrogenic markers in skeletal muscle. Phenotypic indicators of the development of skeletal muscle fibres, intramuscular lipogenesis and collagen development were also evaluated. Modifications in mRNA expression of skeletal muscle of foetuses were observed in function of MN and FS despite the lack of effect of MN and FS on foetal weight at necropsy. Maternal ON increased the mRNA expression of the myogenic marker Cadherin‐associated protein, beta 1 (CTNNB1) and adipogenic markers Peroxissome proliferator‐activated receptor gamma (PPARG) and Zinc finger protein 423 (ZNF423) at midgestation. However, no differences on foetal skeletal muscle development were observed between treatments at late gestation indicating that a compensatory development may have occurred on CO foetuses making the effect of MN on skeletal muscle development not significant at late gestation. Moreover, our data have shown an evidence of sexual dimorphism during foetal stage with a greater skeletal muscle development in male than in female foetuses. In conclusion, providing a higher nutritional level to pregnant cows changes the trajectory of the development of skeletal muscle during midgestation, but apparently does not change the potential of post‐natal growth of muscle mass of the offspring, as no differences in skeletal muscle development were observed in late gestation.     

Reforestation with loblolly pine can restore the initial soil carbon stock relative to a subtropical natural forest after 30 years

We hypothesized that long-term loblolly pine (Pinus taeda L.) land-use restores SOC stock and lability of a subtropical Cambisol to the original levels of the natural forest (NF). Additionally, we hypothesized that roots are the major contributor to SOC and that soil stores most of the ecosystem total carbon (ETC). We investigated a chronosequence of loblolly pine land-use of 17 (first rotation) and 32 years (second rotation, unthinned or thinned) following clearing of the NF. The original SOC stock to 100 cm of NF (209?±?9.4 Mg C ha^?1) was depleted by 22% after 17 years of pine, possibly because of intense soil disturbance and low quantity and quality of the residue inputted during the pine stand implementation. However, the SOC stock was restored to the original stock of NF after 32 years of pine, with the input of above and belowground biomass at harvest of the first rotation possibly playing a role in this recovery. Thinning did not affect SOC stocks after 1 year. The POM-C reduced after 17 years and was not recovered after 32 years. We could not ascertain in 5-year evaluation whether root or litter was the major contributor to SOC. Soil held 72% of the ETC in NF and 48–59% in pine plantations, confirming that it stores most of the ETC. Overall, long-term loblolly pine land-use seems to restore the original soil carbon stock in this subtropical site, regardless of some lability losses.