Duroc Piglets Research Articles

Effect of swine leukocyte antigen-DQA gene variation on diarrhea in Large White, Landrace, and Duroc piglets.

Piglet diarrhea is one of the most common factors that affects the benefits of the swine industry. Although recent studies have shown that exon 2 of SLA-DQA is associated with piglet resistance to diarrhea, contributions of genetic variation in the additional exon coding regions of this gene remain unclear. Here, we investigated variation in exons 1, 3 and 4 of the SLA-DQA gene and evaluated their effects on diarrheal infection in 425 suckling piglets. No variation was identified in exon 1. In exon 3, there were eight alleles detected, generated by 14 single nucleotide polymorphisms (SNPs) and three nucleotide deletions, eight SNPs being newly identified. Four allele sequences and three SNPs were identified in exon 4, only one SNP being newly identified. Statistical analysis showed that the genotypes of exon 3 are significantly associated with piglet diarrhea; indeed, genotypes DQA*wb01/wb02 and wb04/wb05 are clearly associated with resistance to piglet diarrhea, as they have the lowest probabilities of infection (P<0.05). However, no significant association was found between the genotypes of exon 4 and diarrhea (P>0.05). These results provide important new information concerning the level of genetic diversity at the SLA-DQA locus and suggest that further genetic association studies of piglet diarrhea resistance should include analyses of both exons 2 and 3 of this locus.

Genetic association of sequence variation in exon 3 of the swine leukocyte antigen-DQA gene with piglet diarrhea in Large White, Landrace, and Duroc piglets.

Piglet diarrhea is one of the primary factors that affects the benefits of the swine industry. Recent studies have shown that exon 2 of the swine leukocyte antigen-DQA gene is associated with piglet resistance to diarrhea; however, the contributions of additional exon coding regions of this gene remain unclear. Here, we detected and sequenced variants in the exon 3 region and examined their associations with diarrhea infection in 425 suckling piglets using the polymerase chain reaction-single-strand conformational polymorphism and sequencing analysis. The results revealed that exon 3 of the swine leukocyte antigen-DQA gene is highly polymorphic and pivotal to both diarrhea susceptibility and resistance in piglets. We identified 14 genotypes (AA, AB, BB, BC, CC, EE, EF, BE, BF, CF, DD, DH, GG, and GF) and eight alleles (A-H) that were generated by 14 nucleotide variants, eight of which were novel, and three nucleotide deletions. Statistical analyses revealed that the genotypes AB and EF were associated with resistance to diarrheal disease (P < 0.05), and the genotype DD may contribute to diarrhea susceptibility but was unique to Large White pigs (P > 0.05). These results elucidate the genetic and immunological background to piglet diarrhea, and provide useful information for resistance breeding programs.

Effects of dietary supplementation of a zinc oxide product encapsulated with lipid on growth performance, intestinal morphology, and digestive enzyme activities in weanling pigs

The present experiment was performed to investigate the effects of a lipid-encapsulated ZnO product (Shield Zn) on growth, intestinal morphology, and digestive enzyme activities in (Yorkshire×Landrace)×Duroc piglets. A total of 408 21-day-old weanling pigs were allotted by sex and body weight to 12 pens, with 34 animals per pen, in a randomized complete block design. The animals were fed a ZnO-free basal nursery diet supplemented with 125mg ZnO (100mg Zn)/kg (ZnO-100), 3125mg ZnO/kg (ZnO-2500), or 139mg of lipid-encapsulated Shield Zn (100mg Zn)/kg (Shield Zn-100) for 14 days, after which 24 animals were killed for examination of intestinal morphology and digestive enzyme activities. The average daily gain of the Shield Zn-100 group (207g/d) was greater (P<0.01) than that of the ZnO-100 group (184g/d), but was less (P<0.01) than that of the ZnO-2500 group (235g/d). The average daily feed intake was less in the Shield Zn-100 (326g/d) than in the Zn-2500 group (367g/d; P<0.01), not being different between the former and the ZnO-100 group (309g/d; P=0.23). However, the gain:feed ratio was not influenced by the treatment. The fecal consistency (diarrhea) score subjectively measured by a 3-notch integer scale was greater (P<0.01) in the Shield Zn-100 (1.30) and ZnO-100 (1.31) groups vs. ZnO-2500 group (1.06). Hepatic and circulating Zn concentrations were less (P<0.01) in the Shield Zn-100 and ZnO-100 groups vs. ZnO-2500, not being different between the former two groups. The villus height, crypt depth and villus height:crypt depth ratio in the duodenum, jejunum, and ileum as well as specific activities of sucrase, maltase, leucine aminopeptidase in these intestinal regions and amylase and trypsin activities in the pancreas were not influenced by the dietary treatment. In conclusion, the present results indicate that supplementation of Shield Zn at a physiological level is superior to that of native ZnO at the same level in supporting weight gain of weanling pigs, but that the former is inferior to pharmacological ZnO in the growth-enhancing and diarrhea-suppressing effects.

Production of Middle White Piglets after Transfer of Embryos Produced &lt;i&gt;In Vitro&lt;/i&gt;

The present study was conducted to examine the feasibility of in vitro embryo production and transfer technologies for producing Middle White piglets. After collection from three retired Middle White sows, a total of 222 oocytes were matured, fertilized and cultured in vitro, and a total of 50 embryos from the 4-cell to blastocyst stage were produced by the 4th or 5th day. These embryos were transferred individually into three recipients along with 5 in vivo-derived Duroc blastocysts. All of the recipients became pregnant, and they farrowed a total of 9 Middle White and 9 Duroc piglets. These results suggest that in vitro embryo production using ovaries from retired sows is useful for reproduction of pigs of pure breeds including the Middle White for breeding activities and conservation/utilization of genetic resources.

Supplementation with branched-chain amino acids to a low-protein diet regulates intestinal expression of amino acid and peptide transporters in weanling pigs

This study determined the effects of dietary branched-chain amino acids (AA) (BCAA) on growth performance, expression of jejunal AA and peptide transporters, and the colonic microflora of weanling piglets fed a low-protein (LP) diet. One hundred and eight Large White × Landrace × Duroc piglets (weaned at 28 days of age) were fed a normal protein diet (NP, 20.9 % crude protein), an LP diet (LP, 17.1 % crude protein), or an LP diet supplemented with BCAA (LP + BCAA, 17.9 % crude protein) for 14 days. Dietary protein restriction reduced piglet growth performance and small-intestinal villous height, which were restored by BCAA supplementation to the LP diet to values for the NP diet. Serum concentrations of BCAA were reduced in piglets fed the LP diet while those in piglets fed the LP + BCAA diet were similar to values for the NP group. mRNA levels for Na(+)-neutral AA exchanger-2, cationic AA transporter-1, b(0,+) AA transporter, and 4F2 heavy chain were more abundant in piglets fed the LP + BCAA diet than the LP diet. However, mRNA and protein levels for peptide transporter-1 were lower in piglets fed the LP + BCAA diet as compared to the LP diet. The colonic microflora did not differ among the three groups of pigs. In conclusion, growth performance, intestinal development, and intestinal expression of AA transporters in weanling piglets are enhanced by BCAA supplementation to LP diets. Our findings provide a new molecular basis for further understanding of BCAA as functional AA in animal nutrition.

The influence of dietary locust bean gum and live yeast on some digestive immunological parameters of piglets experimentally challenged with Escherichia coli1

Gums and yeast cells are natural mannose-rich products that can be used as subtracts for adhesion of gram-negative bacteria. The aim of the study was to investigate the role of dietary locust bean gum (LBG; Salmosan, ITPSA, Spain) or live yeast (Saccharomyces cerevisiae Sc47; Actisaf, Lesaffre, France) as immunological enhancers of the intestinal function of piglets. Treatments included a noninfected group fed with a control diet and 4 other groups orally challenged with 1x10(8) cfu of Escherichia coli K88. The challenged groups were fed the control or the control diet supplemented with colistin, LBG, or yeast. Twenty-five Landrace × Duroc piglets weaned at 4 wk were used. The animals were group housed, challenged on day 14, and euthanized 2 d later. Blood, bile, ileum, and mesenteric lymph node (MLN) samples were obtained for analysis of C-reactive protein (CRP), secretory immunoglobulin A (sIgA), and Toll-like receptors 2 (TLR2) and 4 (TLR4). Challenge increased the level of CRP of piglets fed the control diet, but this did not happen in the piglets fed the supplemented diets (P < 0.001). Challenge upregulated TLR2 in MLN and TLR4 in ileum and MLN (P < 0.05). This was prevented by yeast supplementation for the TLR2 in MLN and TLR4 in ileum. Pigs fed colistin and LBG diets showed intermediate but nonsignificant responses. In conclusion, the results suggest that colistin, live yeast, and LBG reduce the levels of CRP in blood of piglets challenged with E. coli, and yeast reduces the expression of Toll-like receptors in the intestine.

Achyranthes bidentata polysaccharide enhances growth performance and health status in weaned piglets

This study is conducted to investigate the effects of Achyranthes bidentata polysaccharide (ABP) as a dietary additive on growth performance, plasma parametre profile and the mRNA abundances of IGF-1 and IL-1β in liver, jejunal mucosa and mesentery lymph node. A total of 200 three-hybreded (Landrace×Yorkshire×Duroc) piglets weaned at 28 days of age were allocated into five dietary treatment groups on the basis of body weight and litter of origin in a complete randomised design. Five diets were tested for 35 days, including the basal control diet, the antibiotic treatment diet (basal control diet+500 mg/kg flavomycin), and three ABP treatment diets, in which ABP were added to basal control diet with 500, 1000 and 1500 mg/kg, respectively. There was higher average daily feed intake (ADFI) in animals fed with 500 mg/kg ABP when compared with animals in other groups (P<0.05). However, there was no significant deference in ADFI among animals in control group, antibiotics group (500 mg/kg flavomycin), high dose ABP supplementation group (1000 and 1500 mg/kg ABP) (P>0.05). Flavomycin (500 mg/kg) and different dose of ABP supplementation significantly increased average daily gain (P<0.05). Compared with animals in control group, there was low FiG in animals fed with 500 mg/kg flavomycin, 500, 1000 and 1500 mg/kg ABP, respectively (P<0.05). Flavomycin (500 mg/kg) and different dose of ABP supplementation significantly decreased the diarrhoea frequency of weaned piglets (P<0.05). Moreover, there was lower diarrhoea frequency in animals fed with different dose of ABP compared with animals fed 500 mg/kg flavomycin (P<0.05). Supplementation of ABP increased plasma concentrations of hormones, antibodies, and alkaline phosphatase (P<0.05) and IL-1β mRNA abundance in liver, jejunal mucosa and lymph nodes. These findings indicate that ABP is effective in improving growth performance and defending capacity, which suggests that ABP can be used as a diet additive for weanling piglets.

Influence of diet and rearing system on heavy pig performance, carcass and meat quality

Identifying alternative dietary protein sources and new types of outdoor rearing techniques that enhance animal welfare, thus optimising costs and production performance, are among the main objectives of nutritionists and breeders. The aim of this study was to compare two types of rations where pea and potato concentrate completely substituted soybean in intensively and extensively bred swine.Forty Large White × Duroc piglets weighing about 40 kg were divided into 4 groups of 10 sex- and weight-matched individuals: Indoor rearing + Control diet, Indoor rearing + Experimental diet, Outdoor rearing + Control diet, Outdoor rearing + Experimental diet. Different diets were formulated for the growing phase (40-100 kg) and the fattening period (100-slaughter); pigs, weighed individually every 40 days to estimate the average daily gain and feed conversion rate, were slaughtered when they reached the weight for Italian ham production. The following measurements were obtained: carcass weight, slaughtered yield, weight of lean cuts, pH 45 minutes and 24 hours post mortem. 40 semimembranosus muscle samples were analysed for colour parameters (L*, a* and b*), moisture, fat, protein and ash while the energy values were calculated. Semimembranosus intramuscular fat and ham backfat were analysed for fatty acid profile.Statistical analysis of performances data was conducted using design with repeated measures and the slaughterhouse, meat and fat composition data were subjected to ANOVA. The results show that soybean can be completely substituted with other protein crops. Rearing and slaughterhouse performances were not affected by the diet, whereas significant differences emerged with the rearing system. Diet composition significantly affected lean meat proportion (50.0 vs 48.2) and fat thickness of 3/4 Thoracic Vertebra (25.3 vs 28.3 mm), while the rearing system significantly affected all carcass quality measures. Some parameters were better in outdoorthan indoor-subjects. Meat colour was also significantly influenced by the rearing effect, being less light and yellow in the former subjects (L* 49.9 vs 37.3; b* 3.7 vs 2.3). Chemical analysis demonstrated that the meat of outdoor-reared subjects was leaner (1.96% vs 1.38% fat) and had a lower water content (72.8% vs 71.8%).The complete replacement of soybean is thus compatible with a strong characterization and an enhancement of the value of swine products. In addition, the rearing system can result in distinctive quality features, such as ham colour and fat content, allowing products from outdoor rearing to be clearly recognized from those obtained from intensive rearing.

2, 4-Thiazolidindion Induced Plasticity of Myoblast (C2C12) and Satellite Cells (Porcine) - A Comparative Study

This study was conducted to determine the difference between satellite cells (porcine) and myoblasts (C2C12) in their differentiation under the influence of 2, 4-thiazolidindion. C2C12 myoblast cells and porcine satellite cells (isolated from 10 do ld Landrace×Duroc piglets) were grown to absolute confluency. Post confluent cells (day 0) were further exposed to adipogenic induction medium along with 2, 4-thiazolidindion (8 µM) for 2 d. Thereafter, cells were exposed to 2, 4-thiazolidindion alone every 2 d till day 10 and analysed. The control was cultured in differentiation medium without any treatment. Increased (p<0.05) expression of transcriptional factors i.e. C/EBP-α and PPAR-γ and transition of cells to adipocyte morphology was noticed from 2 d and 4 d onwards in satellite cells (Porcine) and myoblasts (C2C12) respectively. Myogenesis was observed to be suppressed completely in case of satellite cells compared to myoblasts in response to 2, 4-thiazolidindion. Pax-7 (transcriptional factor) appeared as a sole entity to satellite cells only, as it was not identified in case of myoblasts. Although both the cells were converting to adipoblasts, the degree of their conversion was different in response to 2, 4-thiazolidindion. Therefore, the hypothesis that satellite cells contribute various domains to the growing myoblasts appeared obscured and found to be dependent on the proliferative energy/or degree of fusion. However, it revealed satellite cells as currency to myoblasts/muscle. (Key Words : Adipogenesis, Myoblast (C2C12), Satellite Cells (Porcine), Pax-7, 2, 4-Thiazolidindion)

Valor nutritivo e desempenho de leitões alimentados com rações contendo silagem de grãos úmidos de milho

Um ensaio de digestibilidade (experimento 1) foi conduzido para determinar os coeficientes de digestibilidade aparentes da matéria seca (CDMS), proteína bruta (CDPB), amido (CDAM) e energia bruta (CDEB) e o coeficiente de metabolização da energia bruta (CMEB) da silagem de grãos úmidos de milho (SGUM). Foram utilizados 12 suínos mestiços (Landrace, Large-White e Duroc) machos castrados, alojados em gaiolas de metabolismo, distribuídos em um delineamento experimental inteiramente casualizado. O método utilizado foi o da coleta total de fezes e urina. Os valores de matéria seca digestível (MSD), proteína digestível (PD), amido digestível (AD), energia digestível (ED) e energia metabolizável (EM), na matéria natural (60,18% de MS), foram, respectivamente, 48,70; 3,77; 42,35%; 2.389 e 2.327 kcal/kg de SGUM. O experimento 2 foi conduzido para avaliar o desempenho de leitões e a viabilidade econômica da utilização das rações com diferentes níveis de substituição do milho seco por SGUM. Foram utilizados 48 suínos mestiços (Landrace, Large White e Duroc), distribuídos em um delineamento inteiramente casualizado, com seis repetições e dois animais por unidade experimental. Os tratamentos consistiram de uma ração à base de milho e farelo de soja e outras três com 33, 66 e 100% de substituição do milho seco por SGUM com base nos valores de energia digestível. Não houve efeito da inclusão de SGUM sobre o ganho de peso e o consumo de ração, porém ocorreu redução linear na conversão alimentar e no custo da ração por quilograma de peso vivo ganho. Os dados indicam que o milho seco pode ser totalmente substituído pela SGUM em rações para leitões em fase de creche, com melhora nos índices produtivos e econômicos.

Interactions between environmental temperature and porcine growth hormone (pGH) treatment in neonatal pigs

Age-dependent interactions between environmental temperature and porcine growth hormone (pGH) treatment on the function of the somatotrophic axis were evaluated in the neonatal pig. At 3 d of age, 40 Landrace x Yorkshire x Duroc piglets received intraperitoneal implants containing either recombinant pGH (0.5 mg/d; n = 20) or vehicle (control; n = 20). Piglets were maintained at either a low (21°C, 50% relative humidity; n = 20) or high (32°C, 50% relative humidity; n = 20) temperature. At 4 and 6 wk of age, 5 pGH-treated and 5 control piglets from each thermal group were sacrificed for tissue collection. Blood samples were collected at the time of sacrifice and analyzed for serum concentrations of GH, insulin-like growth factor 1 (IGF-1), and IGF-2. Liver RNA was analyzed for mRNAs specific for the GH receptor, IGF-1, IGF-2, and IGF binding protein 3. There was no effect of pGH treatment (P = 0.4) on average daily gain; however, both age (P = 0.002) and temperature (P = 0.001) had an effect on average daily gain such that those animals maintained at a low temperature and those sacrificed at 6 wk had greater average daily gains. Serum concentration of GH was elevated (P = 0.003) by pGH treatment and was lowest in the 6-wk-old group (P = 0.008). Serum concentration of IGF-1 was elevated (P = 0.007) by pGH treatment and increased with age (P = 0.01). Liver GH receptor mRNA was unaffected (P > 0.5) by pGH treatment, but was greater in the 6-wk-old group (P < 0.0001) and in piglets maintained at the high temperature (P = 0.04). IGF-1 mRNA was enhanced by pGH treatment (P = 0.0003) and by exposure to the high temperature (P = 0.04), but did not differ (P > 0.5) between age groups. IGF-2 mRNA was greater (P = 0.0009) in the 4-wk-old group and in piglets maintained at the high temperature (P = 0.007), but was unaffected (P = 0.5) by pGH treatment. IGF binding protein 3 mRNA increased with age (P = 0.0004) and was stimulated by pGH treatment in the 6-wk-old group (P = 0.034). The relatively lower level of GH receptor and IGF mRNAs in conjunction with greater growth in the cold environment suggests that somatotrophic gene expression in the liver is not rate limiting for growth in the neonatal pig.

Variation in the immune status of two Australian pig breeds.

To investigate the variation in immune competence of two Australian pig breeds. A panel of immune tests were used to assess breed and sire differences in weaner piglets of Large White and Duroc breeds. All piglets were immunised against porcine leptospirosis. Blood samples were taken for studies on lymphocyte phenotypes, mitogenic responses of blood cells and serological analysis. Significantly larger blood leucocyte numbers were found in Large White piglets compared with Duroc piglets after vaccinations. No significant difference in concanavalin A induced blood cell proliferation was found between these two breeds before or after vaccinations. Some significant breed variation in blood lymphocyte phenotypes was found. While the age-related changes of lymphocyte phenotypes were similar for the two breeds, the Large White breed had significantly larger numbers of CD2+ and CD4+ cells than the Duroc breed after the two vaccinations. There were also significant sire effects on CD8+ cells within the Large White breed after the first vaccination. No significant breed difference was detectable in serum IgG concentrations but sire differences within each breed before the primary vaccination were found. The serum antibody response to vaccination against leptospirosis was generally small, and showed no variations due to either breed or sire. No gender effects were found during the entire study. The study demonstrated significant differences in some important immune components of the pig breeds studied. This may in turn indicate the variation in their immune competence or disease resistance. However, further investigation into the heritability and correlation with specific immune responses is required.