Vietnamese Pigs Research Articles

Analysis of troponin I gene polymorphisms and meat quality in Mongcai pigs

Troponin I is one of myofibrillar proteins required for the calcium regulation of skeletal muscle contraction. The expression of both genes, TNNI1 and TNNI2, in troponin is muscle fibre specific and may affect meat quality traits. In this study, the PCR-RFLP method was applied to genotype 120 Mongcai pigs at three single-nucleotide polymorphisms (SNPs), namely T5174C, C8350A for TNNI1 (EU743939) and C1167T for TNNI2 (EU696779). The two SNPs, T5174C and C1167T, were significantly associated with drip loss48 (measured after 48 h) and compression force, while the second TNNI1 SNP (C8350A) did not show any association with meat quality traits. The results also revealed a relationship between the proportion of IIx muscle fibre and TNNI2. Additional analysis showed a significant association of the TNNI2 SNP (C1167T) with blood glucose. Animals carrying the CT genotype had the highest glucose concentration (93.7 mg/dL). The results demonstrate that TNNI1 and TNNI2 are likely to play a relatively important role in the development of pork quality in Mongcai pigs.Keywords: TNNI1, TNNI2, drip loss, meat colour, pork, indigenous Vietnamese pigs

Physiological Performance of a Detergent Decellularized Heart Valve Implanted for 15 Months in Vietnamese Pigs: Surgical Procedure, Follow‐up, and Explant Inspection

This study features the longest experimental follow-up for decellularized heart valves implanted in an animal model. Porcine aortic heart valves were decellularized according to a disclosed standardized method in which TRITON X-100 and sodium cholate (TRICOL) are used in succession, followed by a further treatment with the endonuclease Benzonase to completely remove the nucleic acid remnants. Experimental animals (n = 17), represented by Vietnamese pigs (VPs), received a decellularized aortic allograft as a substitute for the replacement of their right ventricular outflow tract. The surgical implantation of the TRICOL-treated aortic valve conduit was successful in 11 VPs, while perioperative or postoperative complications occurred in the remaining six animals. In the sham-operated group (n = 4), the native pulmonary root was excised and immediately reimplanted orthotopically in the same animal. Echocardiography demonstrated a satisfactory hemodynamic performance of the TRICOL-treated valves during follow-up as well as the absence of relevant leaflet alterations concerning thickness and motility or valve insufficiency. At explantation, macroscopic inspection of tissue-engineered heart valve conduits did not evidence calcifications and showed a decreased wall thickness, comparable to that of the reimplanted native pulmonary roots. Noteworthy, extended functional performance, recovery of DNA content, and active extracellular matrix precursor incorporation are apparently compatible with the properties of a living self-supporting substitute.

Uncontrolled admixture and loss of genetic diversity in a local Vietnamese pig breed

The expansion of intensive livestock production systems in developing countries has increased the introduction of highly productive exotic breeds facilitating indiscriminate crossbreeding with local breeds. In this study, we set out to investigate the genetic status of the Vietnamese Black H’mong pig breed by evaluating (1) genetic diversity and (2) introgression from exotic breeds. Two exotic breeds, namely Landrace and Yorkshire used for crossbreeding, and the H’mong pig population from Ha Giang (HG) province were investigated using microsatellite markers. Within the province, three phenotypes were observed: a White, a Spotted and a Black phenotype. Genetic differentiation between phenotypes was low (0.5–6.1%). The White phenotypes showed intermediate admixture values between exotic breeds and the Black HG population (0.53), indicating a crossbreed status. Management practices were used to predict the rate of private diversity loss due to exotic gene introgressions. After 60 generations, 100% of Black private alleles will be lost. This loss is accelerated if the admixture rate is increased but can be slowed down if the mortality rate (e.g., recruitment rate) is decreased. Our study showed that a large number of markers are needed for accurately identifying hybrid classes for closely related populations. While our estimate of admixture still seems underestimated, genetic erosion can occur very fast even through indiscriminate crossbreeding.

Comparative Gastric Morphometry of Muong Indigenous and Vietnamese Wild Pigs

It is hypothesized that despite sharing a similar habitat, the Muong indigenous and Vietnamese wild pigs may reveal different gastric morphology. Due to the protective nature of procuring these pigs, a total of 12 Muong indigenous pigs and nine Vietnamese wild pigs stomach collected post mortem were analysed for selected biometric parameters and histology. The result indicated that the stomach of the Vietnamese wild pig is broader with a bigger capacity and greater proportion of proper gastric glands. Interestingly, the stomach mass correlated well with live body weight in both breeds apart from possessing similar histomorphometry of the gastric gland regions. On the other hand, the thicker (P < 0.05) submucosa in the Vietnamese wild pig is attributed to the presence of numerous loose connective tissues, abundant blood vessels, adipose tissues and nerve plexus. The appearance of lymphoid follicles underneath the tubular gastric glands in the Vietnamese wild pig exceeded that of Muong indigenous pigs. This finding suggested that the difference in feeding behavior as well as immunity. In conclusion, adaptations found in the Vietnamese wild pig indicated that this breed is equipped with a bigger and effectively functional stomach to suit its digestive physiology and immunity in the wild.

Introduction of Various Vietnamese Indigenous Pig Breeds and Their Conservation by Using Assisted Reproductive Techniques

Pigs are one of the most important domesticated animals in Vietnam. They are the main source of meat for the Vietnamese. According to FAO statistics, Vietnam is among the top 5 countries raising pigs in the world, with nearly 27 million hogs. This review article introduces the distribution, morphology, growth potential, meat-producing ability and reproductive efficiency of six Vietnamese indigenous pig breeds: I, Mong Cai, Muong Khuong, Soc, Meo and Co. The collected data showed that these Vietnamese pigs are less effective in comparison with Western pigs in terms of reproductive and meat-producing ability as well as weight growth. However, these Vietnamese indigenous breeds have some special characteristics, such as very early sexual maturity, and good adaptability to harsh raising conditions or poor feeding. Moreover, recent genetic research has shown that Vietnamese pigs are genetically diverse. Thus, conservation of these pig breeds using assisted reproductive techniques is urgent and important.

Assessing Nitrogen and Phosphorus in Excreta from Grower-finisher Pigs Fed Prevalent Rations in Vietnam

Livestock production in Vietnam is, as in most Asian countries, increasing rapidly and changing into specialized highly intensified operations. The volume of animal excreta generated exceeds the capacity of the operation land base and cannot be utilized efficiently. As a consequence, there is a loss of plant nutrients from livestock farms that causes environmental pollution. This study carried out a feed and excretion experiment measuring fecal characteristic, daily fecal production, daily nitrogen and phosphorous excretion from grower-finisher pigs fed prevalent rations in Vietnam. Furthermore, equations for assessing the excretion were tested, which can be used in farm models for optimal recycling of manure while focusing on reducing pollution. The results indicated that fecal production and nutrient excretion were affected by the different rations tested. This study showed that five selected equations for predicting excretion from grower-finisher pigs in Danish conditions can also be used with precision in Vietnamese pig farming systems. The equations have been proven valid and can, therefore, be used as a much needed tool for assessing fecal production and nitrogen in excreta on pig farms. The study also showed that about 12% of nitrogen excreted was emitted during housing. Waste water contains more than half of the nitrogen excreted, mainly in ammonium form which has a high potential for gaseous emission.

Altered expression of c-kit-positive cells in the ureterovesical junction after surgically created vesicoureteral reflux

Peristaltic contractions propel urine unidirectionally from the renal pelvis trough the ureter and into the bladder. A morphologically and functionally competent ureterovesical junction prevents vesicoureteral reflux (VUR). According to current knowledge, pyeloureteral peristalsis is driven by atypical muscle cells within the upper urinary tract. Another likely relevant cell population, which is c-kit-positive, has been shown to be present within the whole urinary tract. Morphological changes of c-kit-positive cells have been described in VUR and pyeloureteral junction (PUJ) obstruction. Nevertheless, the functional importance of c-kit-positive interstitial cells has not yet been elucidated fully. Therefore, we investigated the influence of experimentally created VUR on the expression of c-kit-positive cells. We created left-sided unilateral VUR in eight Vietnamese pigs using an open surgical technique. The VUR was shown to be grade II-III by voiding cystourethrogram (VCUG), 1 and 6 months after the procedure. The animals were killed after 6 months. The vesicoureteral junction and the distal ureters were excised and fixed in 4% PFA. Paraffin sections were stained using c-kit immunohistochemistry. A quantitative evaluation was performed by two independent investigators. The unaffected, contralateral, nonrefluxing ureters served as controls. We identified two types of c-kit-immunoreactive cells within the ureterovesical junction and distal ureter. The first group was comprised of round-shaped cells with substantial intracellular granulas, which resembled mast cells. Mast cells were found in the subepithelial region as well as between the muscle bundles. The number of mast cells was slightly increased in the VUR group. The second group consisted of spindle-shaped, bipolar ICC-like cells, which were seen mainly in the submucosal and muscular layers. The number of spindle-shaped c-kit-immunoreactive cells was markedly decreased in the refluxing ureter compared to the controls. Surgically created VUR leads to altered expression of c-kit-positive cells. The altered distribution of c-kit-positive ICC-like cells might further contribute to the impairment of coordinated pyeloureteral peristalsis.

Zearalenone, deoxynivalenol and aflatoxin B1 and their metabolites in pig urine as biomarkers for mycotoxin exposure

Methods to determine zearalenone (ZEA), deoxynivalenol (DON), aflatoxins (AF) and their metabolites in pig urine were developed as biomarkers for pig exposure to the mycotoxins in feed. Urine samples were incubated with β-glucuronidase to cleave conjugates, extracted and cleaned-up with solid phase and immunoaffinity columns, followed by HPLC with UV and fluorescence detection. Good recoveries (83-130%), low variation (2-10%), and low detection limits (0.3-9.9ng/ml) were obtained. The results of controlled AFB1 feeding trials found no difference in urine concentrations of AFB1 or AFM1 from pigs fed three different levels (127, 227, 327 µg/kg) of AFB1 in diets. The excretion of AFB1 and AFM1 in urine was on average 30% of the oral dose and the ratio AFB1 to AFM1 was around 23%. The analysis of 15 Vietnamese pig urine samples indicate a relatively high exposure of ZEA, DON and AF, which were found as toxin or metabolites in 47, 73, and 80% of the urine samples, respectively.

MtDNA variation in Vietnamese pigs, with particular emphasis on the genetic relationship between wild boars from Vietnam and the Ryukyu Islands

ABSTRACT To examine the genetic origin of Ryukyu wild boar, we sequenced mitochondrial DNA (mtDNA: 574-bp) from Vietnamese wild boar and Vietnamese indigenous domestic pigs and compared these sequences with the mtDNA of Ryukyu wild boar by phylogenetic analysis. Numerous Vietnamese wild boars were genetically related to Ryukyu wild boar, suggesting that descendants of the ancestors of Ryukyu wild boar still inhabit Vietnam. The mtDNA sequences of Vietnamese indigenous domestic pigs are extremely diverse and are thought to have contributed to the diversity of mtDNA among East Asian domestic pigs.

Pig production in Vietnam - a review.

Abstract Pigs are of great importance in Vietnam because of their contribution to human nutrition, their role in agricultural production systems and their economic function. Vietnam's pig herd is the largest in Southeast Asia. This paper reviews the Vietnamese pig production sector. Starting with an overview of natural conditions concerning pig production, including a description of prevalent pig breeds and pig production systems, the paper then takes a systematic view of the pig production infrastructure, including the breeding and feeding as well as the veterinary and extension systems, and product marketing. Finally, the political and economic environment and state policies relevant to pig production are described. While focussing on the present situation, the paper also incorporates information on historical developments, which have led to the current state, and derives trends for future development. This paper reviews published literature, legal documents, and reports accessed from development projects in Vietnam, and additionally includes information obtained from members of development projects, and from key people and stakeholders of the Vietnamese pig production sector.

Dynamics and developmental trends of smallholder pig production systems in North Vietnam

This study analyses developmental trends, and the driving forces behind them, in smallholder pig production systems in the marginalized mountainous areas of North-west Vietnam. Fieldwork was conducted from 2001 to 2002 in a total of 64 households in four villages in North Vietnam of varying remoteness. Data on developments in pig production were derived from structured household interviews and analysed by loglinear models. The findings of Rapid Rural Appraisal on historical developments are also presented. Spreadsheet models were developed simulating four production alternatives: demand-driven pig production with higher-yielding Vietnamese Mong Cai sows or resource-driven production with lower-yielding local Ban sows, generating offspring either through purebred boars of the respective breed or with higher-yielding Large White boars. Starting from the base models of the four genotype/production system combinations, the following scenarios were tested: (1) increased performance through improved management, (2) modification of end products, and variation of (3) input costs and (4) end-product prices. Evaluation variables were gross margin (GM) and net benefit (NB) of pig production. Results show a rapid transition process from subsistence to increasingly market-oriented production, beginning even before the reforms of 1986 (Doi Moi) but gaining considerable momentum afterwards. Differentiation of production systems was observed in regions that differed in remoteness and environmental conditions. In the base model, improved Large White × Mong Cai pigs yielded the highest GM and local Ban pigs the lowest; Large White × Ban pigs yielded the highest NB and Mong Cai pigs the lowest. Under a scenario of considerably increasing feed costs, Large White × Ban pigs became more beneficial than Large White × Mong Cai pigs based on GM as the decision criterion. Modelling results are compared with current conditions in the Vietnamese pig sector. The probability of local Ban pigs becoming a beneficial production alternative is critically discussed, as is the methodological approach of the study.

Comparison of Vietnamese and European pig breeds using microsatellites1

This study characterized autochthonous pig breeds of Vietnam and compared them with breeds from other regions. A total of 343 animals were considered from 5 indigenous pig breeds of Vietnam (Muong Khuong, Co, Meo, Tap Na, and Mong Cai), 2 exotic breeds kept in Vietnam (Landrace and Yorkshire), 3 European commercial breeds (German Land-race, Piétrain, and Large White), the Chinese breed Meishan, and the European Wild Boar. Each individual was genotyped for 20 selected polymorphic microsatellite loci. The Vietnamese autochthonous breeds showed higher degrees of polymorphism, allelic diversity, and heterozygosity than the other pig breeds. Also, large genetic diversity was observed across the area of distribution, with village-specific subpopulations, which led to significant inbreeding coefficients. As expected, genetic distances showed large differences among European-based, Chinese, and Vietnamese indigenous breeds and reflected the geographical distribution of breeds. In comparison with the European breeds, the Vietnamese indigenous pig breeds harbored a considerable amount of genetic diversity and, therefore, will be of significance for livestock bioconservation.

Studies of H5N1 Influenza Virus Infection of Pigs by Using Viruses Isolated in Vietnam and Thailand in 2004

To determine whether avian H5N1 influenza viruses associated with human infections in Vietnam had transmitted to pigs, we investigated serologic evidence of exposure to H5N1 influenza virus in Vietnamese pigs in 2004. Of the 3,175 pig sera tested, 8 (0.25%) were positive for avian H5N1 influenza viruses isolated in 2004 by virus neutralization assay and Western blot analysis. Experimental studies of replication and transmissibility of the 2004 Asian H5N1 viruses in pigs revealed that all viruses tested replicated in the swine respiratory tract but none were transmitted to contact pigs. Virus titers from nasal swabs peaked on day 2, and low titers were detected in the liver of two of the four pigs tested. Our findings indicate that pigs can be infected with highly lethal Asian H5N1 viruses but that these viruses are not readily transmitted between pigs under experimental conditions.

Variation in mitochondrial DNA of Vietnamese pigs: relationships with Asian domestic pigs and Ryukyu wild boars.

Mitochondrial DNA (mtDNA) sequences (574 bp) of 30 Vietnamese pigs (large and small) were examined and compared with those of 61 haplotypes from wild boars and domestic pigs from various locations in Asia. The large Vietnamese pigs had genetic links to Ryukyu wild boars in southern Japan. The small Vietnamese pigs were closely related to other East Asian domestic pigs. These results indicate that Vietnamese pigs are genetically diverse and may be descendents of wild and domestic pigs from other regions of Asia.

Three types of polymorphisms in exon 14 in porcine Mx1 gene.

Much is known about the antiviral activity of Mx proteins in species such as mouse and human. In the mouse, loss of resistability to influenza virus has been shown to be due to specific polymorphisms in the Mx gene. This gene is therefore an interesting candidate gene for disease resistance in farm animals. The porcine Mx1 gene has already been identified and characterized based on its homology with mouse Mx1; however, until now no evidence of polymorphisms in the porcine gene has been reported. In this study, we have found two new polymorphisms in exon 14 of porcine Mx1 by DNA sequencing and confirmed their presence in different breeds, using polymerase chain reaction (PCR)-restriction fragment length polymorphisms (RFLP) with NarI and NaeI restriction enzymes. On the basis of the deduced amino acid sequence, one allele contains a deletion that may result in a frameshift to yield several amino acid substitutions and extension of the carboxyl terminal region of Mx1 protein. The deletion allele, Mx1c, was found to be segregating in Landrace, Berkshire, Duroc, Hampshire, and Yucatan miniature pig. A second point mutation, Mx1b, was detected in Meishan and two Vietnamese native pig breeds. All other breeds tested were fixed for the Mx1a allele that is identical to the sequence reported previously. It will be interesting to determine if the Mx1c deletion is associated with variation in resistance to the myxovirus family in the pig.

Detection of deletion and mutation on pig Mx1 gene (gene resistance to influenza virus) with PCR-RFLP Nar I restriction

The study was done to detect the incident of deletion and mutation in exon 14th of Mx1 gene in pig. Six hundred base pairs at the position (1937 to 2537) of the 14th exon of the pig Mx1 gene was amplified by polymerase chain reaction (PCR) from 15 breed of pig DNA sample. The amplified PCR products were digested by Nar I enzyme that called restriction fragment length polymorphism (PCR-RFLP) technique. The results show genetic polymorphism at the 14th exon of pig Mx1 gene. The Nar I digested revealed three phenotyphic variation (C/C, C/N and N/N, designated for Nar I cut homozygote, heterozygote and for Nar I no cut homozygote, respectively). The Nar I (N/N or C/N) type is corresponding to (1) the deletion 11 bp at the position 2064 to 2075. This type was observed in Landrace breed. (2) the incidence of two point mutation at the position 2065 Guanine (G) change to Thymine (T) and at the position 2124 Guanine (G) change to Adenine (A).This type was observed in Chinese native pig (Meishan) and Vietnamese native pig. Key words : Deletion, mutation, pig Mx1 gene and PCR-RFLP

Acute septicaemic pasteurellosis in Vietnamese pigs

Sixteen isolates of Pasteurella multocida were cultured from cases diagnosed as acute septicaemic pasteurellosis in Vietnamese pigs. The HSB–PCR assay provided rapid presumptive determination of 10 isolates of P. multocida identified as haemorrhagic septicaemia (HS) causing type B cultures (B:2, B:5, B:2,5). Serological designation using the Carter and Heddleston typing systems confirmed these findings, and identified the six HSB–PCR negative cultures as either A:1, A:3 or D:3,4. Biochemical fermentation and REP–PCR revealed phenotypic and genotypic identity between P. multocida type A:1 isolated from Vietnamese pigs and poultry. Marked homogeneity was also demonstrated among HSB–PCR positive swine isolates, which were shown to possess genotypic identity with P. multocida type B:2 from buffaloes diagnosed with HS.

Effect of body composition, feed intake, and ambient temperature on heat production of Vietnamese Sway-back pigs.

From theoretical considerations animals with a higher protein-fat ratio in the body should have a higher maintenance energy requirement (MEm). The literature on this problem shows a non-uniform picture with deviating results. From the results of a series of experiments it is possible to compare the heat production (HP) of male and female animals of the Vietnamese Sway-back breed pigs which vary quite widely in their body composition. The protein-fat ratio was 1.2 for the male and 0.2 for the female animals. In the experiments 4 male and 4 female animals in the live weight range of 20-33 kg and 33-42 kg, respectively, were involved. The HP measurements were carried out in climatized respiration chambers on two levels of energy intake at ambient temperatures of 6 degrees C, 12 degrees C, 18 degrees C, 24 degrees C, 30 degrees C, and 35 degrees C. The dependence of HP on the ambient temperature has been described by a cubic regression function. Thermoneutral temperatures are lower in the female animals caused by the better insulation effect of the backfat. The difference in HP which was expected by the large difference in body composition, was not found. The absolute protein mass determined the correlation to HP. Certainly the difference increased after lowering the ambient temperature. The influence of different factors on HP is discussed.

Morphological and Histochemical Type Differentiation of Muscle Fibres in Newborn Piglets of the Vietnamese Breed

Kaman J.: Morphological and Histochemical Type Differentiation of Muscle Fibres in Newborn Piglets of the Vietnamese Breed. Acta Vet. Brno, 82, 1993: 139-149. A standard histological technique and a histochemical detection of myosin Ca­ ATPase with acid and alkaline pre-incubation were used in a study of 11 topo­ graphically and functionally different muscles in 11 male and female newborn piglets. Both extra- and intrafusal muscle fibres (MFs) of the newborns were fully morphologically and adequately histochemically differentiated. The myosin Ca­ ATPase detection method was used to differentiate between acid stable and alkali unstable muscle fibres of Type I, alkali stable and acid unstable muscle fibres of Type II (in some cases differentiated further into muscle fibres of Type IIA and lIB), and the intermediary muscle fibres of Type IIC with the MS, SS and, sporadically also SM subtypes transforming into Type I fibres. An objective type identification of muscle fibres is only possible when a comparison of myosin Ca-A TPase reactions in serial sections after acid and alkaline pre-incubations are made. The muscles examined were classified into two basic groups. Those with a higher number (2-7) of Type IIC fibres in the primary bundle (in. sternomastoideus, m. trapezius, m. tibialis cranialis) exhibited better morphological, and particularly histochemical, differentiation than others: these were characterized by a smaller number of Type IIC fibres with largely uniform morphological, but different histochemical, characteristics on the surface as well as in deep in the muscle. In view of our findings and because pigs belong to nidifugous mammals, we reject the views suggesting that the myofibrillar hypoplasia of muscle fibres in newborn piglets of meat breeds is a physiological phenomenon. Skeletal muscles, muscle fibre, morphological differentiation, type differentiation, histo­ chemistry, myojibrillar hypoplasia, splayleg, Vietnamese pig, newborn pig

Some characteristics of a laboratory produced strain of Oesophagostomum dentatum

The isolation of Oesophagostomum dentatum from pig is described, and several morphological characteristics of the parasite and some special features about its life-cycle are illustrated and discussed. Ninety-eight female worms with a tail-length of about 350 μm were isolated from one sow. The eggs were separated from the uterus and transferred to a culture medium. The infective larvae obtained were fed to a Vietnamese miniature pig. As a control for the species isolation, a Belgian landrace pig was infected with 2000 L 3, which had originated from the Vietnamese pig. Eight weeks later the control animal was slaughtered; the tail-length of 200 female worms isolated was measured. The measurements showed a symmetric and normal distribution with a mean of 313.23 μm. Five three-month-old sows were each infected orally with 50 000 O. dentatum larvae. The prepatent period was found to be between 26 and 28 days. The egg-counts fluctuated widely and after killing the pigs only a small number of mature worms were found to be present. Histological examination of the mucosa of the intestines did not show a prolonged histotropic phase. Two hundred worms from each pig were measured, and the lengths were 8.72 to 10.83 mm for females, 7.70 to 8.74 mm for males. The length of the spicules ranged from 1004 to 1043 μm, and the tail-length of the females from 299 to 18.75 μm. Only the measurements of the tail-length belonged to a symmetric population. The adult worms had a buccal capsule with parallel sides and a club-shaped oesophagus.