Dynamics of porcine circovirus type 2 infection in a herd of pigs with postweaning multisystemic wasting syndrome

OBJECTIVE: To determine the pattern of infection for porcine circovirus type 2 (PCV2) in a herd of pigs with postweaning multisystemic wasting syndrome (PMWS). ANIMALS: 29 sows and 250 pigs. PROCEDURE: Blood samples were collected from all 3-, 7-, and 12-week old pigs and 59 pigs at 28 weeks of age. Pigs that died during the study were necropsied. Porcine parvovirus and PCV2 antibodies were assayed. A polymerase chain reaction (PCR) was used to detect PCV2 genome in serum of selected pigs. RESULTS: The PMWS started when pigs were 8 weeks old, with a prevalence of 30% in 8- to 10-week-old pigs. Eighty-three pigs died during the period between 3 and 12 weeks of age. Microscopic lesions consistent with PMWS were observed, and PCV2 nucleic acid was detected (50 of 68 pigs). Antibodies to PCV2 decreased from 3 to 7 weeks of age, increased at 12 weeks of age, and were maintained until 28 weeks of age. One sow had a positive result for PCR of serum. Nine, 37 and 8 pigs had PCV2 genome in serum obtained at 7, 12, and 28 weeks of age, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with PCV2 coincided with severe clinical signs; however, infected 28-week-old pigs did not have evidence of disease. Immunity declined over time in young pigs. A long duration of PCV2 viremia was apparent in a high percentage of infected pigs, which may affect transmission and persistence of the virus in a herd.     

Seed Shattering of Cañahua (Chenopodium pallidicaule Aellen)

Cañahua (Chenopodium pallidicaule Aellen) is a semi‐domesticated relative of quinoa (Chenopodium quinoa Willd.) with high nutritious quality. It is tolerant to frost, drought, saline soils and pests. One seed yield limitation is seed loss during the maturity stages. Two greenhouse experiments in Denmark and field experiments in Bolivia were carried out to determine seed shattering in landraces and cultivars with different growth habits. 15–21 % of the seed shattering in the fields took place whilst the plants still were flowering and 25–35 % during physiological maturity. Seed shattering varied between locations on the Bolivian Altiplano. Cañahua types with the semi‐prostrate growth (‘lasta’) had the highest seed shattering rate in the greenhouse experiments. The Umacutama landrace had lower seed shattering (1 %) than the cultivar Kullaca (7.2 %) both of the ‘lasta’ type. Under field conditions, the cultivar Illimani with the erect growth (‘saihua’) had the highest seed shattering rate (6.4–33.7 %) at both locations and at four different sowing dates. The Umacutama had the lowest rate (0.5–1.5 %). There were no significant differences between plants of the ‘lasta’ and the ‘saihua’ types. The landrace had significantly less seed loss than the cultivars. However, in the greenhouse, the landrace yield was approximately 25 % lower than the yields of the cultivars. In general, cañahua cultivars had higher yield compared to landraces, but also a higher seed shattering rate. Landraces may be used in breeding programmes to develop high‐yielding cultivars with reduced seed shattering.     

Pregnancy Rate in Zebu Cows with Two Different Postpartum Intervals Exposed to a Two-Bull Rotational System

In order to evaluate the reproductive effect of a rotational breeding system, the pregnancy rate of 69 Zebu cows was assessed, 32 late postpartum (211±93 days postpartum, LP) and 37 early postpartum (averaging 63±8 days after calving, EP). In the LP group, 60% (19/32) were cycling before exposure to the bulls but only 38% (14/37) in the EP group. The two groups were dissimilar from the start (p<0.05). The cows were exposed in a rotational breeding system, with six Brahman bulls with previous sexual experience paired off in three groups (A–B, C–D and E–F). The cows were exposed to each pair of bulls for a period of 3 weeks, with one week in between each period, when the females were without the presence of a male. In the LP group, the pair of bulls A–B obtained a pregnancy rate of 72% (23/32), whereas for bulls C–D the pregnancy rate was 33% (3/9) and for bulls E–F the pregnancy rate was 67% (4/6). In contrast, for the EP cows, bulls A–B obtained a pregnancy rate of 32% (12/37), bulls C–D a pregnancy rate of 67% (12/18) and for bulls E–F a pregnancy rate of 55% (6/11). The percentage pregnancy obtained using the pair of bulls A–B differed (p<0.05) between LP and EP, whereas for bulls C–D and E–F it was similar. The pregnancy rate was different (p<0.05) in the first 3 weeks of mating for the LP group, the highest number of cows becoming pregnant during the first 3 weeks of the study. In contrast, the highest number of pregnancies in EP occurred evenly during the last 6 weeks. This study suggests that the reproductive performance of pairs of bulls in a 9-week rotational programme with the overall pregnancy rate is similar (94% in the LP and 81% in the EP). However, the time taken for the females to become pregnant, and hence the performance of the bulls, is related to the average number of days postpartum for the cows.     

Diversity of Cryphonectria parasitica in western Spain and identification of hypovirus‐infected isolates

Isolates of the chestnut blight fungus Cryphonectria parasitica were obtained from 44 localities in four provinces in Western Spain and characterized for vegetative compatibility (vc) types, mating types and the presence of Cryphonectria hypovirus 1 (CHV1). Among the 1232 isolates recovered from chestnut blight cankers, 11 vc types were identified: five known vc types included in EU1 to EU74 (EU1, EU11, EU12, EU28 and EU66) and six unknown vc types (CL4, CL5 CL6, CL8, CL9 and CL10). The number of vc types found per province varied between two and seven. The vc type EU11 was present in all provinces and accounted for 48.9% of all isolates. EU1 was detected in three provinces and accounted for 39.1% of the isolates. The vc types EU12, EU66, CL5 and CL6 were present in one or two provinces and comprised between 2.4% and 3% of the isolates. The other vc types were represented by only one or very few isolates. The mating type MAT‐1 was largely dominant in the provinces Leon and Avila, while both mating types MAT‐1 and MAT‐2 were found in Salamanca and Zamora. Fourteen hypovirus‐infected C. parasitica isolates were found, nine were in vc type EU1 and five in EU11, and they were detected only in the province León. All isolates analysed contained the French hypovirus subtype CHV1‐F1.     

Chemical Characterization and Release of Polyphenols from Pecan Nut Shell [<Emphasis Type="Italic">Carya illinoinensis</Emphasis> (Wangenh) C. Koch] in Zein Microparticles for Bioactive Applications

The pecan nut [Carya illinoinensis (Wangenh) C. Koch] is a natural source of polyphenols with antioxidant properties. In this study, the encapsulation of aqueous and hydroalcoholic extracts of pecan nut shell were evaluated for the release of bioactive compounds and antioxidant potential in order to explore food applications using zein as encapsulating agent. The extracts showed high contents of total phenolics, condensed tannins and high antioxidant activity. Concentrations of proanthocyanidins were 9-fold higher in hydroalcoholic extracts. The LC-DAD analysis showed that catechins were the major phenolic compounds in samples, with epigallocatechin levels up to 138.62 mg mL^?1. Zein microparticles loaded with aqueous extract released 2.3 times more phenolic compounds than the hydroalcoholic extracts and the DSC thermograms showed that extracts of pecan nut shell remained thermally stable up to 240 °C. The zein microcapsules obtained in this study were efficiently encapsulated and represent an interesting additive due its high antioxidant capacity, physicochemical characteristics and morphology. The use of zein microparticles combined with natural extracts constitute a step forward in the improvement of current technology for delivering phenolic compounds with applications in functional foods and nutraceuticals.     

Chronological study of Mycoplasma hyopneumoniae infection, seroconversion and associated lung lesions in vaccinated and non-vaccinated pigs

A field trial was conducted to study Mycoplasma hyopneumoniae (Mh) infection dynamics by nested polymerase chain reaction (nPCR) and serology in pigs of a farm affected by enzootic pneumonia (EP). Moreover, correlation of Mh detection at different respiratory tract sites with presence of EP gross and microscopic lung lesions was assessed. These parameters were studied and compared between vaccinated (two doses at 1 and 3 weeks of age versus one dose at 6 weeks of age) and non-vaccinated pigs. Animals were monitored from birth to slaughter by nPCR from nasal swabs and by serology. From 3 to 22 weeks of age, an average of three pigs per treatment and per batch were necropsied (n = 302). The remaining pigs were sent to the slaughter (n = 103). Nasal, bronchial and tonsillar swabs were taken from the necropsied/slaughtered pigs; gross and microscopic EP-suggestive lung lesions were also assessed. Single and double vaccination resulted in earlier seroconversion and higher percentage of Mh seropositive pigs compared to control group. At slaughter, double vaccinated pigs showed lower percentage of EP-compatible gross lung lesions and lower Mh prevalence at upper respiratory tract sites (nasal cavity and tonsil) than control pigs.     

Modelling transport of chokka squid (Loligo reynaudii) paralarvae off South Africa: reviewing,testing and extending the ‘Westward Transport Hypothesis’

Annual landings of chokka squid (Loligo reynaudii), an important fishing resource for South Africa, fluctuate greatly, and are believed to be related to recruitment success. The ‘Westward Transport Hypothesis’ (WTH) attributes recruitment strength to variability in transport of newly hatched paralarvae from spawning grounds to the ‘cold ridge’ nursery region some 100–200 km to the west, where oceanographic conditions sustain high productivity. We used an individual‐based model (IBM) coupled with a 3‐D hydrodynamic model (ROMS) to test the WTH and assessed four factors that might influence successful transport – Release Area, Month, Specific Gravity (body density) and Diel Vertical Migration (DVM) – in numerical experiments that estimated successful transport of squid paralarvae to the cold ridge. A multifactor ANOVA was used to identify the primary determinants of transport success in the various experimental simulations. Among these, release area was found to be the most important, implying that adult spawning behaviour (i.e., birth site fidelity) may be more important than paralarval behaviour in determining paralarval transport variability. However, specific gravity and DVM were found to play a role by retaining paralarvae on the shelf and optimizing early transport, respectively. Upwelling events seem to facilitate transport by moving paralarvae higher in the water column and thus exposing them to faster surface currents.