Anthelmintic resistance impact on tropical beef cattle productivity: effect on weight gain of weaned calves

The performance of grazing cattle in tropical areas is deeply influenced by parasitism, and the increasing reports of resistance are a threat to effective nematode control. The present study aimed to evaluate the effect of avermectins on the performance of weaned calves naturally infected by ivermectin-resistant gastrointestinal nematodes. The effect of four commercial endectocides (ivermectin 2.25 % + abamectin 1.25 %, ivermectin 3.15 %, doramectin 3.15 %, and doramectin 1 %) on parasitism and performance of a hundred weaned Nellore calves were evaluated during 112 days. The most effective anthelmintic showed efficacy of 84 % and resulted in an increase (P?<?0.05) of live weight gain of 11.85 kg, compared to untreated group, 9.05 and 9.41 kg compared to those treated with more ineffective avermectins which showed efficacy of 0 and 48.2 %, respectively. A significant (P?<?0.05) and weak negative correlation (r?=??0.22) between the eggs per gram (EPG) and body weight was observed, indicating that even the low mean EPG (175?±?150) observed at day 0 in the control group, with predominance of Haemonchus sp., was responsible for production losses. These results indicate that control of nematode parasites in beef cattle in the weaning phase may not result in increased productivity when carried out without technical criteria.     

Comparison of the Central Composite Rotatable Design with Doehlert Matrix on the Optimization of the Synthetic Dairy Effluent Treatment

The objective of this work was to optimize the synthetic dairy effluent (SDE) treatment using the central composite rotatable design (CCRD) and the Doehlert matrix to evaluate the adjustment of the models to the data, besides verifying if it is possible to find the same optimum point to the turbidity removal, chemical oxygen demand (COD), and UV₂₅₄ compounds using two experimental designs. The coagulation and flocculation assays were made in jar test and the flotation in a flotatest in bench scale. For each experimental design, the effect of two organic coagulants was evaluated in the removal of turbidity, COD, and UV₂₅₄ compounds of the SDE: the polyacrylamide (PAM) and the Tanfloc. The generated mathematical models in both experimental designs adjusted well to the data, showing a high capacity of prediction. To the PAM coagulant, the optimal point found in the CCRD design was 46.49 mg L^?1 of coagulant in a pH of 6.53; in the Doehlert design, the optimal point in the CCRD was 48.40 mg L^?1 of coagulant in a pH of 6.50. When Tanfloc was used, in the CCRD, the optimal point found was 40.42 mg L^?1 of coagulant in a pH of 5.00 and, in Doehlert design, the optimum found was 37.57 mg L^?1 in a pH of 5.05. It is concluded that, using a smaller number of runs, through Doehlert design is possible to find the optimal point really close to the obtained through CCRD in which are observed efficiencies of similar pollutant removal.     

Evaluation of Vertical-Flow Constructed Wetlands for Swine Wastewater Treatment

In this study, the role of Cyperus sp. was evaluated for removal of pollutants from swine wastewater. Vertical-flow pilot scale constructed wetlands (CWs) operating with a hydraulic retention time (HRT) of 72 h were monitored in a greenhouse, located in Viçosa, Brazil. Significant differences were observed for the following parameters: Kjeldahl nitrogen, total phosphorus, alkalinity and electric conductivity, with averages removals of 37.5 and 28.5%, 55.9 and 44.4%, 30.2 and 25.6 and 26.1% and 22.9% (for planted and unplanted CWs, respectively). The rate of dry matter yield from Cyperus sp. was 7.5 g?m^?2 day^?1, and the nutrient uptake capacities were 21.8, 2.1, 14.0 and 0.9 g?m^?2 of N, P, K and Na, respectively. Evapotranspiration (2.7 mm day^?1) was statistically higher in the planted CWs. Plants in the CWs are important for achieving high nutrient removal.     

A New Basic Chromosome Number for the Genus Brachiaria (Trin.)Griseb. (Poaceae: Panicoideae: Paniceae)

The genus Brachiaria (Trin.) Griseb. has been characterized as having two basic chromosome numbers to this date: x = 7 and x = 9, with the predominance of the latter. Cytological studies performed on five accessions of Brachiaria dictyoneura (Fig. et De Not.). Stapf revealed a new chromosome number for the genus, x = 6. The origin of x = 6 is still unknown. All accessions examined for this species presented 2n = 24 and typical meiotic abnormalities of polyploids. The use of such accessions in the Brachiaria hybridization breeding program is discussed.     

The seven impediments in invertebrate conservation and how to overcome them

Despite their high diversity and importance for humankind, invertebrates are often neglected in biodiversity conservation policies. We identify seven impediments to their effective protection: (1) invertebrates and their ecological services are mostly unknown to the general public (the public dilemma); (2) policymakers and stakeholders are mostly unaware of invertebrate conservation problems (the political dilemma); (3) basic science on invertebrates is scarce and underfunded (the scientific dilemma); (4) most species are undescribed (the Linnean shortfall); (5) the distribution of described species is mostly unknown (the Wallacean shortfall); (6) the abundance of species and their changes in space and time are unknown (the Prestonian shortfall); (7) species ways of life and sensitivities to habitat change are largely unknown (the Hutchinsonian shortfall).Numerous recent developments in taxonomy, inventorying, monitoring, data compilation, statistical analysis and science communication facilitate overcoming these impediments in both policy and practice. We suggest as possible solutions for the public dilemma: better public information and marketing. For the political dilemma: red-listing, legal priority listing and inclusion in environmental impact assessment studies. For the scientific dilemma: parataxonomy, citizen science programs and biodiversity informatics. For the Linnean shortfall: biodiversity surrogacy, increased support for taxonomy and advances in taxonomic publications. For the Wallacean shortfall: funding of inventories, compilation of data in public repositories and species distribution modeling. For the Prestonian shortfall: standardized protocols for inventorying and monitoring, widespread use of analogous protocols and increased support for natural history collections. For the Hutchinsonian shortfall: identifying good indicator taxa and studying extinction rates by indirect evidence.     

Combining ability among apomictic and sexual parents of Urochloa humidicola

The diallel cross constitutes an informative genetic design for choosing genitors and crosses in breeding programmes since it provides estimates of general (GCA) and specific (SCA) combining abilities. Because the breeding programme for Urochloa humidicola ([Rendle] Morrone & Zuloaga; syn. Brachiaria humidicola [Rendle] Schweick) at Embrapa Beef Cattle is recent, these estimates are still unknown. Thus, the aim of this study was to obtain the estimates of GCA and SCA from the partial diallel cross design between sexual and apomictic parents. The crosses involved nine sexual and ten apomictic parents. Seventy‐one full‐sib progenies were obtained and evaluated in an incomplete block design, using all parents and the cv. BRS Tupi as a check. The agronomic and forage quality traits were evaluated using seven harvests. Statistical analysis was performed using the mixed model approach. Significant variations were associated with GCA among sexual parents for biomass yield and forage quality traits. However, this cannot be observed for apomictic parents for GCA. The SCA effect was not significant for the assessed traits. These results showed the predominance of additive effects. Sexual parents SEX3 and SEX4 presented the highest potential for contributing favourable alleles in hybrid combinations. The absence of GCA among apomictic parents and SCA suggests the need to increase genetic variability for the generation of breeding populations of U. humidicola.     

Use of trichostatin A alters the expression of HDAC3 and KAT2 and improves in vitro development of bovine embryos cloned using less methylated mesenchymal stem cells

The aim of this work was to investigate the methylation and hydroxymethylation status of mesenchymal stem cells (MSC) from amniotic fluid (MSC‐AF), adipose tissue (MSC‐AT) and fibroblasts (FIB‐control) and to verify the effect of trichostatin A (TSA) on gene expression and development of cloned bovine embryos produced using these cells. Characterization of MSC from two animals (BOV1 and BOV2) was performed by flow cytometry, immunophenotyping and analysis of cellular differentiation genes expression. The cells were used in the nuclear transfer in the absence or presence of 50 nM TSA for 20 hr in embryo culture. Expression of HDAC1, HDAC3 and KAT2A genes was measured in embryos by qRT‐PCR. Methylation results showed difference between animals, with MSC from BOV2 demonstrating lower methylation rate than BOV1. Meanwhile, MSC‐AF were less hydroxymethylated for both animals. MSC‐AF from BOV2 produced 44.92 ± 8.88% of blastocysts when embryos were exposed to TSA and similar to embryo rate of MSC‐AT also treated with TSA (37.96 ± 15.80%). However, when methylation was lower in FIB compared to MSC, as found in BOV1, the use of TSA was not sufficient to increase embryo production. MSC‐AF embryos expressed less HDAC3 when treated with TSA, and expression of KAT2A was higher in embryos produced with all MSC and treated with TSA than embryos produced with FIB. The use of MSC less methylated and more hydroxymethylated in combination with embryo incubation with TSA can induce lower expression of HDAC3 and higher expression of KAT2A in the embryos and consequently improve bovine embryo production.     

The evolution of a discard policy in Europe

Ocean sustainability is a widespread public concern in Europe, and the issue of fisheries discards is one that is now widely known. With this increase in public awareness comes the need to adapt fisheries management policies to manage issues like fisheries discards that were not previously taken into account. In this context, this study analyses the evolution of the European Union's discard policy since its inception in 2006 until the present day and the events that shaped its current format. It analyses the policy's advantages and disadvantages, and its political, environmental and scientific consequences. It argues that an increase in public awareness, due to public campaigns against fisheries discards, has focused managers' attention onto a symptom of fisheries mismanagement, rather than on its underlying causes of over‐exploitation and lack of fisheries control. This has distorted the discussion of the reform of the Common Fisheries Policy and potentially undermined its provisions relating to discards.     

Evaluation of microalgae and industrial cheese whey as diets for Tapes decussatus (L.) seed: effects on water quality, growth, survival, condition and filtration rate

As reference diets for bivalve molluscs are missing, this study first evaluated the best mixed algal diet (Tetraselmis suecica Butch/Phaeodactylum tricornutum Bohlin) concentration for 4‐mm‐length Tapes decussatus (L.) clams. It also assessed the performance of an industrial by‐product (cheese whey) as a single diet or supplement for the best algal ration previously determined. Growth, survival, condition index and filtration rate were used to compare the different diets. Implications of rations tested on rearing water quality were also investigated, especially ammonium and heterotrophic bacteria levels. With a food concentration as algal dry weight per total seed live weight of 0.7% day^?1, seed for grow‐out (7 mm) could be obtained within 1 month. A mixture of 25% algal ration and 75% cheese whey gave the best performances. Artificial diets resulted in lower growth rates than live food (20 % to 40% of the best algal ration), but could be considered good maintenance rations in energetic terms. Using cheese whey, and without any algae, hatchery produced seed can be kept economically indoors for at least 30 days without loss in condition.