Detection of Toxoplasma gondii DNA in Fresh and Frozen Semen from Rams in Brazil

The aim of this study was to estimate the prevalence of genomic DNA of Toxoplasma gondii in semen samples from commercial rams in artificial insemination centres in Brazil, as well as in fresh semen from rams in the northeast of Brazil. In total, 108 semen samples were obtained from artificial insemination centres, and genomic DNA of T. gondii was detected in 24 of 108 (22.2%). The prevalence of antibodies anti‐Toxoplasma gondii among sheep on rural properties was 9.2% (10/109), and 100% of the semen samples of these animals were positive in the PCR for T. gondii DNA. The molecular identity was confirmed through sequencing, which indicated 99.9% similarity with the T. gondii DNA sequences stored in the GenBank. This study reports the first occurrence of T. gondii DNA in the semen of rams, which came from artificial insemination centres in Brazil, as well as the occurrence of T. gondii DNA in the fresh semen of naturally infected rams in the northeast of Brazil.     

KAP1．3基因与绵羊产毛性能的相关分析

本实验采用PCR—SSCP的标记技术,对羊毛纤维组成蛋白中的KAP1.3的部分序列进行多态性的研究。结果表明,在引物1中,BB基因型的产毛量性状极显著高于其他基因型（p〈0．01）,在拉伸长度性状上,AB基因型与BB基因型差异极显著（p〈0．01）,AA基因型与BB基因型差异显著（0．01〈p〈0．05）。在引物2中,各基因型不存在显著差异。     

Prevalence of <Emphasis Type="Italic">Toxoplasma gondii</Emphasis> and <Emphasis Type="Italic">Neospora caninum</Emphasis> infections in sheep from Federal District,central region of Brazil

Serum samples from 1028 sheep were collected from 32 herds within Federal District, in the central region of Brazil. The samples were examined by indirect fluorescent antibody test (IFAT) using sera diluted 1:64 and 1:50 as cut-off values for the detection of antibodies against Toxoplasma gondii and Neospora caninum, respectively. The observed prevalence for T. gondii infection was 38.22% (26.81%<CI 0.95<49.62%), and the titers ranged from 64 to 65536. The observed prevalence for N. caninum infection was 8.81% (7.08%<CI 0.95<10.53%). The titers ranged from 50 to 51200. The reactant sera to both pathogens corresponded to 4.67% of the samples. The risk factors were not determined because of the absence of negative herds for T. gondii and the high proportion of positive herds for N. caninum (87.50%). The prevalence for T. gondii infection was significantly higher among males than in females. The present work is the first report on seroprevalence of T. gondii and N. caninum in sheep from Federal District and shows that infection by both parasites is widespread in the ovine population from this region.     

Photo-Assisted Degradation,Toxicological Assessment,and Modeling Using Artificial Neural Networks of Reactive Gray BF-2R Dye

This work investigates the degradation of Reactive Gray BF-2R dye (a blend of reactive yellow 145, reactive orange 122 and reactive black 5 dyes) using UV/H₂O₂, Fenton, and photo-Fenton-advanced oxidative processes, with artificial sunlight and UV-C radiations. The photo-Fenton process employing UV-C radiation was the most efficient under the conditions studied. The ideal conditions for the degradation of the dye, determined using a factorial design 2³ and a study of the concentration of hydrogen peroxide ([H₂O₂]), were [H₂O₂] equal to 40 mg L^?1, iron concentration [Fe] of 1 mg L^?1, and pH between 3 and 4. The Chan and Chu non-linear kinetic model predicted the kinetic data with a degradation of over 98% for color and 68% for aromatics after 60 min. The behavior of the chemical oxygen demand fitted the first-order kinetic model well, with a degradation of 64% after 60 min. The Multilayer Perceptron 7-11-2 artificial neural network model enabled to model the degradation process of the aromatics and accurately predict the experimental data. Toxicity tests indicated that the post-treatment samples were non-toxic for Escherichia coli bacteria, and Portulaca grandiflora and Basil sabory seeds. However, they inhibited the growth of Lactuca sativa seeds and Salmonella enteritidis bacteria. The photo-Fenton process with UV-C radiation degraded the dye studied efficiently and the degradation percentages were, on average, 7% and 5% higher for color than those observed when employing the Fenton and UV/H₂O₂ processes, respectively. With the aromatic, however, they were 84% and 62% higher, thus justifying the use of this process.     

Effect of feeding frequency on growth and enzymatic activity of Litopenaeus vannamei during nursery phase in biofloc system

This study evaluated the zootechnical performance and enzymatic activity of Litopenaeus vannamei reared at different feeding frequencies during the nursery phase in biofloc system. The experiment consisted of four treatments, corresponding to the feeding frequencies of one, two, three and four times a day. Twelve‐day postlarvae (PL12) were stocked in 12 circular tanks at a density of 3,000/m² for 35 days. These tanks were connected to a recirculation system supplied by a matrix tank where biofloc management was carried out. Water quality remained within acceptable limits for the species over the experiment. Food frequencies had no influence on survival (88.5–92.7%) and feed conversion ratio (1.5–1.7), but the final mean weight (0.43–0.56 g) was significantly higher in shrimp fed three times a day. This fact is probably associated with amylase (14.58 U/mg) and trypsin (23.84 U/mg) activities, as well as the significant increase of chymotrypsin (11.74 U/mg) and lipase (1.27 U/mg) in shrimp of this treatment at the end of culture period. Feeding three times a day provided the highest enzymatic activity and the best zootechnical performance of L. vannamei during the nursery phase in biofloc system.     

Effects of addition of Navicula sp. (diatom) in different densities to postlarvae of shrimp Litopenaeus vannamei reared in a BFT system: Growth,survival, productivity and fatty acid profile

The objective of this study was to evaluate the effect of the addition of Navicula sp. on the growth and fatty acids profile of Litopenaeus vannamei postlarvae in a biofloc system (BFT). Four treatments were used: BFT; BFT 2.5N (addition of 2.5 × 10⁴ cells/ml of Navicula sp.); BFT 5N (addition of 5 × 10⁴ cells/ml of Navicula sp.) and BFT 10N (addition of 10 × 10⁴ cells/ml of Navicula sp.), all in triplicate. The shrimp (1 ± 0.01 mg) were stocked at a density of 3,000 postlarvae/m³ and fed with commercial feed. The diatom was added every 10 days, and at the end of 42 days, shrimp performance, water quality and proximal composition were evaluated. The BFT 5N and BFT 10N treatments had higher performance values, highlighting the values of productivity (2.30 and 2.42 kg/m³) and specific growth rate (15.92 and 16.08%/day), which were higher than the other treatments. In addition, the highest levels of fatty acids were observed in treatments with diatom (BFT 5N and BFT 10N), indicating the benefits of Navicula sp. on growth enhancement and fatty acid content of L. vannamei postlarvae grown in biofloc systems.