Evaluation of transcutaneous Doppler ultrasonography for the measurement of blood flow in the femoral artery of pigs

OBJECTIVE: To compare measurements of blood flow in the common femoral artery obtained by duplex Doppler ultrasonography (DDU) and a reference ultrasonic transit-time flow (TTF) method and to examine the impact of Doppler spectral waveform measurement techniques on volumetric estimates. ANIMALS: 5 healthy female pigs. PROCEDURES: Femoral arterial blood flow was measured simultaneously in anesthetized pigs by use of a TTF probe (left femoral artery) and transcutaneous DDU (right femoral artery). A range of flow states was induced pharmacologically by using xylazine, bradykinin, dobutamine, and isoflurane. Volumetric blood flow was calculated from DDU waveforms, using the product of the flow velocity integral (FVI), the cross-sectional vessel area, and heart rate. Three calculations of FVI were obtained by manually tracing the Doppler spectral envelopes at the outer envelope, the modal, and the inner envelope of the spectral dispersion pattern. Data analysis included calculation of Pearson correlation coefficients and Bland-Altman limits of agreement. RESULTS: Blood flow measured by DDU was more closely correlated with TTF measurements when the modal or inner envelope tracing method was used (r, 0.76 and 0.78; limits of agreement, -100 to 54.2 and -48.5 to 770 mL/min, respectively). Limits of agreement for the outer envelope tracing method were -238.5 to 64 mL/min. CONCLUSIONS AND CLINICAL RELEVANCE: Transcutaneous DDU is a reliable noninvasive technique for measuring blood flow in the femoral artery of pigs over a range of flow states. Tracing the inner envelope of the Doppler spectral dispersion pattern provided the best estimate of blood flow in this study.     

Compensatory growth of Nile tilapia Oreochromis niloticus,L. subjected to cyclic periods of feed restriction and feeding in a biofloc system

The compensatory growth, productive performance, proximal composition and somatic indices of Nile tilapia (Oreochromis niloticus) cultivated in biofloc were evaluated during a 144‐day period under five cyclic regimes of feed restriction and feeding. Five treatment groups, in which the frequency of feed restriction (R) and feeding (F) varied by periods (days) as follows: R1:F3, R3:F9, R6:F18, R8:F24 and R12:F36; each treatment was evaluated in triplicate. The cycles were repeated throughout the culture period. The control group received feed daily. Fish were cultivated in 18 circular tanks (3 m³) at a density of 50 fish/m³ per tank. At the end of the study, the survival of Nile tilapia was greater than 90% in all the treatments. Complete compensation in growth was achieved in R6:F18 and R12:F36. At the end of the feed restriction period, both crude protein and total lipid content of the tilapia muscle tissue taken from fish of the treatment groups were similar to samples of muscle tissue derived from fish of the control group; however, a reduction of more than 40% in somatic indices compared with the control was observed, but these recovered by the end of the feeding phase. The results indicate that cyclic feeding based on 12 days of feed restriction and 36 days of feeding (R12:F36) induced a complete compensation in weight and restoration of energy reserves, with similar measures of productive performance observed when compared to the control treatment during the culture of Nile tilapia in biofloc, and food reduction did not affect proximal composition.     

A molecular tool for parentage analysis in the Mediterranean mussel (Mytilus galloprovincialis)

Estimation of selection response and genealogical tracing in family mixtures require an appropriate tool for parentage analysis. In this study, we tested 19 marker loci for parentage analysis allocation in Mediterranean mussel (Mytilus galloprovincialis). To this aim, we reared families in tanks isolated from wild mussel seed, analysed them using the 19 marker loci and characterized their performances based on Mendelian rules. Probabilities of exclusion of a false parent were estimated for different groups of loci and contrasted to the real paternity assignment. Based on this, we chose nine microsatellites with the highest exclusion probabilities and a real paternity assignment of 99.6%. Next, we analysed 600 individuals reared as in the usual production process, where contamination from wild seed is likely. We obtained a real assignment of 94.7% and were able to identify individuals from the wild as the most likely hypothesis to explain the observed incompatibilities with candidate parents. This information was used to evaluate parental contribution in offspring obtained from gamete mixtures of several parents, which bestowed results of interest for future breeding programs of Mediterranean mussel.     

Effects of age, body weight, and heart rate on transmitral and pulmonary venous flow in clinically normal dogs

OBJECTIVE: To determine the influence of age, body weight (BW), heart rate (HR), sex, and left ventricular shortening fraction (LVSF) on transmitral and pulmonary venous flow in clinically normal dogs. ANIMALS: 92 client-owned dogs 3 months to 19 years old. PROCEDURE: Transthoracic Doppler echocardiography recordings of transmitral flow and pulmonary venous flow were obtained in conscious unsedated dogs. Influence of age, BW, HR, sex, and LVSF on diastolic variables was assessed, using statistical methods such as ANOVA on ranks and univariate and multivariate forward stepwise linear regression analyses. RESULTS: Age significantly influenced isovolumic relaxation time (IVRT, r = 0.56), ratio between peak velocity of the early diastolic mitral flow wave-to-peak velocity of late diastolic mitral flow wave (E:A; r = -0.44), deceleration time of early diastolic mitral flow (DTE; r = 0.26), and peak velocity of atrial reversal pulmonary venous flow wave (AR-wave; r = 0.37). Significant changes of mitral inflow and pulmonary venous flow variables were evident only in dogs > 6 and > 10 years old, respectively. Body weight significantly influenced DTE (r = 0.63), late diastolic flow duration (r = 0.60), and AR duration (r = 0.47), whereas HR significantly affected DTE (r = -0.34), IVRT (r = -0.33), and peak velocity of AR (r = 0.24). Sex or LVSF (range 22 to 48%) did not influence any echocardiographic variables. CONCLUSIONS AND CLINICAL RELEVANCE: Age, BW, and HR are important factors that affect filling of the left atrium and left ventricle in clinically normal dogs.     

Genotypic characterization of Chilean llama (Lama glama) and alpaca (Vicugna pacos) pestivirus isolates

Llamas and alpacas are domesticated South American camelids (SACs) important to ancestral population in the Altiplano region, and to different communities worldwide where they have been introduced. These ungulates have shown to be susceptible to several livestock viral pathogens such as members of the Pestivirus genus, in particular Bovine Viral Diarrhea (BVDV), but there is little data available on Pestivirus infections in SACs. In this study we aimed to detect and identify Pestivirus genotypes and subgroups infecting SACs in both wild and confined environments. Samples were collected from 136 llamas and 30 alpacas from different areas in the Chilean Altiplano (wild animals), and from 22 llamas and 26 alpacas diagnosed as Pestivirus positive from the Metropolitana region in Chile (confined animals). Seroneutralization tests showed titers lower than 2 in all 166 samples from Chilean Altiplano. These samples were also negative to BVDV isolation, indicating that these animals have not been exposed to Pestivirus. After reactivation of positive samples from the Metropolitana region, the 5′ non-codifying region (5′NCR) and E2 glycoprotein were amplified by RT-PCR from the Pestivirus genome. Viral sequences were pairwise compared and phylogenetic trees were constructed. The 5′NCR analysis showed that all 12 sequenced isolates belonged to BVDV-1. Of particular interest, isolates from eight llama and two alpaca were BVDV-1j and two alpacas were BVDV-1b. In agreement with these results, E2 phylogenetic analysis rendered a similar grouping indicating that all 16 isolates belong to BVDV-1. However, the lower availability of E2 sequences determines the creation of a smaller number of sub-groups than the 5′NCR sequences. Based on the E2 sequences, the 5′NCR BVDV 1j group consisting of all the llamas and 3 alpacas are completely included in the E2 BVDV 1e group. Due to the universal availability of the 5′NCR segment, we propose the classification of these Chilean llamas and alpacas Pestivirus isolates as BVDV 1j and BVDV 1b respectively. Thus, this is the first time BVDV-1j is obtained in SACs. In addition, these results indicate Pestivirus infection in llamas and alpacas is associated with bovine population as genotypes and sub-groups are the same as those affecting Chilean livestock.     

Comparison of mortality of wild and released reared 0-group turbot, Scophthalmus maximus, on an exposed beach (Ría de Vigo, NW Spain) and a study of the population dynamics and ecology of the natural population

Abstract  Marked reared turbot, Scophthalmus maximus (L.) (594) were released onto an exposed beach nursery ground together with marked wild fish (438) of approximately the same size (4–6 cm TL) and were sampled at intervals for 38 days. A consistent ratio of marked wild: unmarked wild indicated that marking did not increase mortality. The wild 0-group turbot population size was estimated at 1540 at the time of release, indicating that hatchery-reared individuals could theoretically make a significant contribution to the local population size. However, the absolute and relative catches of the marked, reared fish were lower than those of the marked wild fish, and no reared fish were caught after 23 days. The higher mortality rate was attributed to both a smaller size and their hatchery-reared origin. The population dynamics of the 1994–1995 year-classes of wild turbot were also studied. Recruitment of post-larvae (3 cm) to the beach started in March and continued until October. Population size peaked over the August–October period. Juvenile turbot remained on the nursery beach until June of the following year when they presumably emigrated to deeper water. During this 15-month period their length increased from 3 to 12–15 cm.