Archivos de Medicina Veterinaria

Aquaculture diversification: a Chilean program for the future

Revista Archivos de medicina veterinaria — 2016-12-30

In the productive agenda of Chile, the aquaculture industry represents one of the strategic areas for growth of national economy, which searchs for production diversification as a mechanism to reduce the impact of fluctuations on the economic and market environment. The growing global demand of food generates multiple opportunities. The UN estimate that the world population will exceed 9,000 million people in 2050. Current sources of food (agriculture, livestock and fisheries) will be insufficient to meet global food demand. While food production through agriculture and livestock is growing at a rate of 2% per year, fishery production is not, and food production through marine aquaculture has grown over 7% per year (FAO 2013). In the scenario of global aquaculture, our country has achieved a leading position among supplier and producers, thanks to sustained growth of salmon farming, and more recently of mussels. This development has required an investment in training the necessary human capital, technological capabilities and generate own experience; process in which universities and institutions of technical and higher education play a key role in training professionals, technicians and skilled manpower to meet the needs of the industry in areas such as production, processing, marketing etc., as well as service areas. All this has allowed to achieve an increase in productivity and exportation of products to international markets.

Campylobacter: fluoroquinolone resistance in Latin-American countries

H. Fernández — 2016-12-30

Campylobacter jejuni and C. coli are zoonotic bacteria recognised as a major cause of human gastroenteritis and frequent cause of bacterial food-borne illness around the world. A great variety of food-producing animals, especially poultry are important reservoir involved in their spread to humans. Campylobactergastroenteritis is generally a self-limiting disease avoiding antimicrobial prescription but, when antibiotic therapy is indicated, erythromycin and fluoroquinolone are the drugs of choice. However, Campylobacter has become increasingly resistant to fluoroquinolones with high isolation rates among human and animal strains. This review shows and discusses the data generated in Latin America in relation to fluoroquinolone resistance in Campylobacterhighlighting that i) fluorquinolone resistant strains are reported with high frequencies in several countries; ii) the available data allows to confirm that human infection by fluoroquinolone-resistant Campylobacter are originated mainly from the food chain animals and environmental sources; iii) Campylobacter isolation, identification and antimicrobial susceptibility testing have been performed with different analytical methods making necessary the harmonisation and standardisation of diagnostic methods and iv) strengthening Campylobacter antimicrobial resistance surveillance programs and capacity building with the association between public health services and the academic world are necessary.

Genetic-economic comparison of New Zealand Holstein and Jersey-New Zealand Holstein cross under a pastoral scheme in southern Chile

J. Delgadillo — 2016-12-30

Chilean bovine dairy production needs to increase milk solid content. This study evaluates and compares genetic and economic progress of New Zealand Holstein (HoNZ) and New Zealand Jersey-HoNz crossbreed (Fx) using selection indices. The traits analysed were: milk (L) with 3% fat and 3% protein (LB), fat (kg) over 3% in LB (PF), protein (kg) over 3% in LB (PP) and body weight (BW). A multivariate mixed model was used for genetic parameters estimation using AIREMLF90 software. Economic values were estimated using costs associated with dry matter (DM) intake required to supply energy requirements of each trait and income as defined by PROLESUR payment to producer scheme for LB, PF and PP. Genetic progress of PF, PP and BW were similar for the two studied genotypes, but LB progress was higher in HoNz. Economic progress was similar between genotypes, but the offspring of Fx achieves a greater economic benefit per animal and per surface of land, due to higher production of PF and PP. Genetic improvement of Fx using a selection index, allows to achieve higher average of solids production and higher economic benefit.

Cardiac biomarkers in dogs with visceral leishmaniasis

V. B.C. Silva — 2016-12-30

Although only a few studies have focused on the cardiac alterations in Leishmania spp. infected dogs, myocardial inflammation ascribed to such parasite has been documented in some animals. In spite of the increasing popularity of cardiac biomarkers in veterinary medicine in recent years, it remains unknown how most of these substances would perform in dogs with visceral leishmaniasis. In this study, we hypothesised that Leishmania spp. would damage cardiac myofibers resulting in increased circulating levels of cardiac specific markers in dogs. Therefore, biomarkers of myocyte injury and stress were investigated in 18 dogs with naturally-occurring visceral leishmaniasis presenting varying clinical signs, including completely asymptomatic animals. The median (min-max) concentrations of NT-proANP, NT-proBNP, cTnI, and CK-MB were 1138.0 (875-1175) pmol/L, 1160.0 (803-2034) fmol/L, 0.22 (0.15-0.51) ng/mL, and 116.7 (113-222) U/L, respectively. No differences were documented for the concentration of the natriuretic peptides and CK-MB in accordance with the severity of clinical signs, but for cTnI a significant difference was reported when comparing asymptomatic and symptomatic animals. Also, the compromise of renal tubular function seemed to interfere with the concentration of the natriuretic peptides and cTnI. In conclusion, all cardiac-specific biomarkers were elevated when compared to the normal range previously proposed for dogs. Measuring specific cardiac biomarkers has the potential to non-invasively document myocardial injuries attributable to visceral leishmaniasis.

Platelet indices in dogs with thrombocytopenia and dogs with normal platelet counts

A. M. Souza — 2016-12-30

It is well known that thrombocytopenia is the most commonly acquired haemostatic disorder in dogs and can be potentially life-threatening. With the use of automated analysers, platelet indices such as Mean Platelet Volume (MPV), Platelet Distribution Width (PDW), and Platelet Large Cell Ratio (P-LCR), became routinely available, allowing data comparison and error checks which results in a more effective quality control. The aim of this study was to evaluate the pattern of platelet indices (MPV, PDW and P-LCR) in dogs with thrombocytopenia and with normal platelet values. The results of 351 CBCs processed in an automated veterinary haematology counter Sysmex^® pocH-100iV Diff were analysed. Two groups of dogs were established, those with thrombocytopenia (45) and those with normal platelet counts (306). Thrombocytopenic dogs were subdivided in dogs with less than 150,000 platelets/μL of blood (19/42,2%) and dogs with over 150,000 platelets /μL of blood (26/ 57,8%). Mean values of PDW and P-LCR indices in thrombocytopenic animals were significantly higher than the mean values of animals with normal platelet counts. There was no significant difference in any of the indices in either group of thrombocytopenic dogs. Macroplatelets were present in the blood smears of thrombocytopenic dogs. Results suggested increased thrombopoiesis and release of different sized platelets. It was concluded that both PDW and P-LCR increase in dogs with thrombocytopenia and they are more sensitive than MPV. P-LCR is also important in thrombocytopenic dogs, especially when associated to the presence of large platelets in blood smears.

Serological survey of anti-Salmonella antibodies in coatis (Nasua narica) and raccoons (Procyon lotor) in southeast Mexico

J. L. de-la-Rosa-Arana — 2016-12-30

Infectious diseases are important threats for the conservation of wild carnivores, particularly when these animals are in close proximity to humans and domestic animals. However, available data regarding zoonotic infectious diseases in wild carnivores in tropical areas are scarce. The aim of this work was to perform a serological survey of Salmonella and other zoonotic bacteria in coatis (Nasua narica) and raccoons (Procyon lotor) from a semi-urban tropical environment. Coatis and raccoons were trapped and chemically restrained between 2009 and 2011. A total of 100 serum samples, 44 from coatis and 56 from raccoons, were analysed. Antibodies were determined using a commercial agglutination kit (Febriclin^®), and antigens "O" and "H" of Salmonella typhi, S. paratyphi "A", Brucella abortus and Proteus OX-19 were analysed. Antibodies against Salmonella typhi were found but not against the other bacteria. The general seroprevalence for Salmonella typhi antibodies was 63.6% for coatis and 67.9% for raccoons. Titers for both species ranged from 1:20 to 1:80. Antibodies to the "O" antigen were more prevalent (59.1% for coatis and 62.5% for raccoons) than those for the "H" antigen (36.4% for coatis and 50% for raccoons). Seroconversion and a loss of antibodies were detected. The results suggest that both procyonid populations had a high contact rate with Salmonella, although at a low titer level, but there was no evidence of contact with other zoonotic bacteria.

Incidence of ovarian follicular cysts and their effect on reproductive performance in dairy cows: A case study in Mexico

J. L. Pesántez — 2016-12-30

The incidence of ovarian follicular cysts (OFC) in relation to reproductive performance in a dairy herd was determined. A total of 1,249 reproductive records of cows during their previous lactation cycle were reviewed. Of all cows submitted to reproductive evaluation due to anestrus or to diagnose pregnancy, 23% (290/1249) had OFC; 44% (128/290) developed OFC after first service; and 30% of those with OFC (86/290) were found to be open upon diagnosis of pregnancy (40 to 45 days). Cows with pathological puerperium had a higher (Odds ratio 1.5) incidence of OFC than those with normal puerperium (pathological = 26% vs. normal = 20%). Multiparous cows had a higher (Odds ratio 2.2) incidence of OFC (27.5%) than primiparous cows (15.5%). The percentage of non-pregnant cows 150 days postpartum was higher (P < 0.05) in cows with OFC (76%) than in those without OFC (24%); furthermore, the percentage of non-pregnant cows 300 days postpartum was higher (P < 0.05) in cows with OFC (24%) than in those without OFC (3%). It is concluded that 23% of cows developed OFC, and the only sign was anestrus. The cows that developed OFC had a greater probability of remaining open 300 days postpartum, which demonstrates the negative impact of this ovarian condition on modern milk herds.

A note on the changes in the preweaning growth of Pelibuey lambs

J. Oliva-Hernández — 2016-12-30

The aim of this study was to determine the influence of age of dam (AD), type of birth (TB) and age of the lamb (AL) on growth measured in terms of body weight (BW) and average daily gain (ADG) in intermediate stages between birth and weaning of the Pelibuey lambs. Twenty-two Pelibuey ewes (primiparous = 10 and multiparous = 12) and their lambs (n = 34) were used in a 2 x 2 x 5 factorial design. The factors were AD (primiparous and multiparous), TB (single and multiple) and AL (1, 10, 20, 30 and 60 days old). BW and ADG of lambs between birth and 60 days old was studied. BW and ADG were affected (P < 0.05) by TB, AL and the interaction TB x AL. However, BW and ADG were not affected (P > 0.05) by AD and the interaction AD x AL. In conclusion, the body weight and average daily gain of the lambs were affected by type of birth, age of lamb and type of birth x age of lamb.

Ease of handling, physiological response, skin lesions and meat quality in pigs transported in two truck types

F. A. Dalla Costa — 2016-12-30

A total of 1,728 pigs were transported to slaughter using two double-decked trucks, one featuring a hydraulic deck (HD) to load and unload the upper level and the other presenting a fixed upper deck (FD) only accessible by a ramp. The aim of the research was to evaluate the effects of the loading and unloading system of the truck on behaviour, blood parameters (cortisol, lactate and creatine kinase [CK]), skin lesions and meat quality traits. The use of HD resulted in easier and faster loading (P < 0.05 for both) compared with the FD. Blood cortisol levels were influenced by the loading/unloading system, with lower (P < 0.05) levels being found in pigs using HD transport when compared to those using FD transport. Truck type had no effect on the incidence of skin lesions and pork quality in this study (P > 0.05). It can be concluded that the use of the truck model featuring the upper hydraulic deck should be recommended to ease of handling at loading improving animal welfare and reducing the work load of handlers.

Tiludronate infusion in horses previously submitted to bone scintigraphy

C. A. Dörner — 2016-12-30

This study was performed to evaluate the systemic short-term effects of tiludronate intravenous infusion on serum biochemical variables when administered as one single-dose in horses that undergo bone scintigraphy within 24 to 36 hours prior to treatment. Thirty-eight horses were enrolled in the study. Fifteen horses received a dose of technetium (0.3 mCi/kg), MDP (20 mg; medronate) and another fifteen horses received technetium (0.3 mCi/kg), MDP (20 mg), and furosemide (1 mg/kg). Then, 24 to 36 hours after the bone scintigraphy, eight horses were selected and received tiludronate (500 mg in 5L of 0.9% NaCl). Blood samples were collected 15 minutes prior, 24 and 48 hours after the treatment and a chemistry panel was assayed on the day of collection. Serum chemistry values were not significantly different between horses receiving tiludronate and those in both control groups. Additionally, one horse showed mild transient signs of colic recorded as pacing and stretching in the stall after 3 hours the injection of the tiludronic acid. The results suggest that tiludronate can be administered safely as one single dose in horses having undergone recent bone scintigraphy without additional complications or detrimental effect other than those previously described for the drug.

Frequency and antimicrobial behaviour of thermophilic Campylobacter species isolated from Ecuadorian backyard chickens

S. Ochoa — 2016-12-30

The prevalence and antimicrobial behaviour of Campylobacter jejuni/coli isolated from backyard chickens from Southern Ecuador were determined. This study revealed that Campylobacter sp. frequency was 41.7% with high resistance to tetracycline (94.0%) and ciprofloxacin (88%). C. jejuni was the most frequently isolated species (32.5%), followed by C. coli (9.2%) being poultry colonization by Campylobacter not region dependent. This is the first study on Campylobacter antimicrobial resistance in backyard chickens in Southern Ecuador.

Haematological and blood biochemical changes induced by the administration of low doses of Escherichia coli lipopolysaccharide in rabbits

A. K. Peñailillo — 2016-12-30

The aim was to investigate the haematological and blood biochemistry changes of adult rabbits after two intravenous administrations of low-doses of E. coli lipopolysacharide (LPS). Six clinically healthy rabbits were distributed through a cross over design to experimental groups: Group 1 (LPS) treated with two intravenous doses of 1 μg/kg bw of E. coli LPS at 6 h intervals. Group 2 (Control) treated with an equivalent volume of saline solution (SS) at similar intervals. Rectal temperature (T°R), serum concentrations of interleukin-6 (IL-6), C-reactive protein (CRP), haemogram, and the activity of enzymes aspartate aminotransferase (AST) and gamma glutamil transferase (GGT) were measured before and after LPS or SS administration. The administration of LPS in rabbits induced significant increases in IL-6 and CRP concentrations. Leukopenia associated to significant decreases of monocytes, lymphocytes and platelet count, with no significant changes in neutrophil count, were observed at 4 and 8 h after LPS administration. There were significant increases in total leukocytes and neutrophils count at 12 and 24 h. No significant changes (P > 0.05) were observed in mean values of PCV, total proteins, albumin and in the activity of enzymes AST and GGT. The administration of low doses of E. coli LPS induces a fast increase in body temperature, haematological and biochemical shifts, which are milder and have a lower intensity and shorter than previous reports in rabbits treated with high doses of LPS. These changes seem to be consistent with an initial inflammatory response induced by a gram-negative infection.

Polysiphonia spp as epibiont of Caligus rogercresseyi (Crustacea: Copepoda) in Salmo salar farming centers

R. Jaramillo — 2016-12-30

The association between Polysiphonia spp and ovigerous females of Caligus rogercresseyi is analysed. Females carrying egg sacs exhibited individuals of Polysiphonia spp externally attached to the cuticle of both dorsal cephalothorax and abdomen by a mounting disk without penetrating the tissues.