H. C. Azevedo

Hormonal induction and semen characteristics of tambaqui Colossoma macropomum.

In the hatchery-bred tambaqui Colossoma macropomum, spontaneous semen release does not occur, and hand-stripping produces reduced semen volume. The goal of this work is to evaluate the effects of hormonal induction with carp pituitary extract (CPE) on both qualitative (visual aspect, pH, motility, viability and morphological abnormalities) and quantitative (volume, concentration and number of spermatozoa per ejaculate) traits of tambaqui semen. Eleven males were treated with CPE (induced), and 11 were left untreated as a control (non-induced). All analysed parameters except motility and percentage of viable spermatozoa presented significant differences (p < 0.05) between the induced and non-induced treatments. CPE induction resulted in a 25-fold increase in semen volume and a 10-fold increase in the number of spermatozoa collected. However, both sperm concentration and the frequency of sperm with morphological abnormalities (commonly detached heads or bent tails) were significantly lower in CPE-induced fish. The hormonal induction of tambaqui males with CPE is efficient and positively influences some qualitative and quantitative properties of semen. Additionally, semen collection via gentle abdominal massage occurs more readily in CPE-induced fish.

Genetic factors of sheep affecting gastrointestinal parasite infections in the Distrito Federal, Brazil

Three sheep farms were used in the Distrito Federal, Central Brazil, to study the occurrence of parasites in the feces. A total of 1798 collections were taken over the period of a year. A total of 1205 were taken in Santa Inês breed (SI) in all three farms, 323 in Bergamasca (Berg), 54 in Ile de France, 49 in IlexSI, 103 in Morada Nova (MN) and 64 in TexelxSI, these last five groups being on a single farm. The animals were drenched soon after weaning and feces collected every 3 weeks to calculate fecal egg count (FEC), at least on two occasions on each animal. In some cases, blood was collected to determine packed cell volume (PCV) at fecal collection. Fixed effects included farm, breed/genetic group within farm, animal age (months), birth type (simple, twin) and sex. (Co)variance components were estimated for Santa Inês sheep using restricted maximum likelihood under an animal model. FECs were affected by month and farm showing that climate and management are important sources of variation for the parasites studied. While age and birth type of the lambs did not affect infection level, their genetic group was important, showing that breeding strategies can help control these parasites. Heritabilities for infection level in the sheep varied between 0.09 for Strongyloides and 0.31 for Moniezia expansa. Genetic selection strategies for sheep aimed at reducing these infections should result in more resistant animals.

Avaliação de uma metodologia profilática contra a mastite clínica em ovelhas da raça Santa Inês

Mastitis is an important problem for the Santa Ines ewes and is a disease strongly related to the management carried out in the herd. A comparative study was carried out between the proposed method based on drying (treatment) and the traditional method (control). Sixty-two Santa Ines ewes raised in a semi-extensive system were divided in two groups of 31 ewes each: treatment group (G1) and control group (G2). The animals were monitored each week searching for clinical sings of mastitis. In 8.4% of G1 and 41.3% of G2 animals, the udder was warm and hyperemic. The presence of residual milk was lower in G1 (24.3%) compared to those of G2 (74.2%). The proposed treatment for the control of ovine mastitis significantly reduced the frequency of the clinical signs of the disease.

Use of cryotubes for the cryopreservation of tambaqui fish semen (Colossoma macropomum).

Tambaqui (Colossoma macropomum) is a freshwater fish of great importance to aquaculture in several South American countries. Recent studies have developed a protocol for semen cryopreservation in 0.25 and 0.5 mL straws; however, this technique has limitations for fingerling production at a large scale due to the high fecundity of tambaqui. The main objective of this study was to evaluate the feasibility of using cryotubes (1.6 and 4.5 mL) for tambaqui semen cryopreservation. Semen samples were diluted in freezing solution (5% glucose solution, 10% methylglycol, 5% egg yolk), stored in 1.6 and 4.5 mL cryotubes, frozen in liquid nitrogen vapor at -175°C and transferred to a cryogenic container at -196°C. The cryotubes were thawed in a water bath at 60°C for 70 or 90 s and the motility (total motility - TM; progressive motility - PM; curvilinear velocity - VCL; straight line velocity - VSL and average path velocity - VAP) and the viability of sperm were evaluated. There was no significant difference in sperm motility and viability post-thawing between 1.6 and 4.5m L cryotubes, except for TM (47% and 40%, respectively). Thawing for 90 s provided better results, being used in fertilization trials. Although the fertilization rate did not differ between the cryotubes (41-45%), it was significantly lower than that for fresh semen (74%). A strong positive correlation was observed between the sperm motility and fertilization rate (r=0.69-0.89). We conclude that 1.6 and 4.5 mL cryotubes have high potential for tambaqui semen cryopreservation when thawed for a minimum time of 90 s at 60°C.

Estimação de parâmetros genéticos de ovinos da raça Santa Inês utilizando modelos uni e bicaracterística

Objetivou-se nesse trabalho, estimar os parâmetros geneticos para caracteristicas de crescimento em ovinos da raca Santa Ines atraves do Metodo da Maxima Verossimilhanca Restrita (REML). Os componentes de (co)variâncias e os parâmetros geneticos foram estimados pelo Software MTDFREML (Multiple Trait Derivative-Free Restricted Maximum Likelihood). As caracteristicas avaliadas em modelos uni e bicaracteristica foram: peso ao nascimento (PN) e peso ao desmame (P90). Alem dos efeitos fixos de sexo, grupo contemporâneo e tipo de parto, foram utilizados os seguintes efeitos aleatorios: efeito genetico aditivo direto, efeito genetico aditivo materno e efeito residual. As estimativas de herdabilidade aditiva direta para PN foram 0,20 e 0,21, para os modelos uni e bicaracteristica, respectivamente. As estimativas de herdabilidade aditiva direta para P90 foram 0,04 e 0,07, para os modelos uni e bicaracteristica, respectivamente. A correlacao genetica entre PN e P90 foi de 0,11, indicando que ambas as caracteristicas devem ser trabalhadas simultaneamente.

Rapid serum agglutination and agar gel immunodiffusion tests associated to clinical signs in rams experimentally infected with Brucella ovis

The purpose of this study was to evaluate the agar gel immunodiffusion and the rapid serum agglutination tests associated to clinical signs in rams experimentally infected with Brucella ovis. The serological profile during the 12 months of infection showed a large fluctuation of antibodies that favors the failure in the diagnostic. The evaluation of tests after the experimental infection allowed to suggest that none of the tests were able to detect the infection throughout the period of study. The study reinforces the importance of considering the clinical signs to support the diagnosis of Brucella ovis infection in rams.

Teste de soro aglutinação rápida e do teste de imunodifusão em gel de ágar associados aos sinais clínicos em carneiros infectados experimentalmente com Brucella ovis

The purpose of this study was to evaluate the agar gel immunodiffusion and the rapid serum agglutination tests associated to clinical signs in rams experimentally infected with Brucella ovis. The serological profile during the 12 months of infection showed a large fluctuation of antibodies that favors the failure in the diagnostic. The evaluation of tests after the experimental infection allowed to suggest that none of the tests were able to detect the infection throughout the period of study. The study reinforces the importance of considering the clinical signs to support the diagnosis of Brucella ovis infection in rams.