Equine chorionic gonadotropin pretreatment 15 days before fixed-time artificial insemination improves the reproductive performance of replacement gilts

Fixed-time artificial insemination (FTAI) technology uses exogenous reproductive hormones to regulate the sexual cycle and ovulation of sows without oestrus identification, which improves the sow breeding utilisation rate, reduces the number of non-productive days, and elevates the efficiency of pig farm management. In this study, we aimed to optimise FTAI procedures. Healthy 190-day-old and about 90 kg Large White × Landrace crossing breed replacement gilts (n = 166) which were of unknown reproductive status were randomly selected and divided into three groups: a control group (n = 62), an eCG-15D group in which the gilts were pretreated with equine chorionic gonadotropin (eCG) injection 15 days before starting FTAI (n = 50), and an eCG-20D group pretreated with eCG injection 20 days before starting FTAI (n = 54). All three groups were then subjected to the same conventional FTAI procedure. Pigs were orally administered Altrenogest (ALT, 20 mg per pig per day) for 18 days and then 42 h after ALT feeding was stopped, they were injected with 1 000 IU eCG followed by 100 μg GnRH 80 h later. The gilts were inseminated for the first time 24 h after gonadotropin-releasing hormone (GnRH) injection and then again 16 h later. After 42 h of ALT feeding, gilts in the eCG-15D group displayed a higher follicular diameter until artificial insemination (AI) than those from the other groups (P < 0.05). In addition, the ovulation times were the most synchronised in the eCG-15D group, with 100% of the gilts ovulating before the second AI on day 25 of FTAI. Furthermore, the gilts in the eCG-15D group achieved the highest pregnancy rate (92%), farrowing rate (90%), total pigs born (11.59), and pigs born alive (11.18). Together, the findings of this study demonstrate that reproductive performance can be optimised by pretreating gilts with eCG 15 days before conventional FTAI.     

Effect of VNTR polymorphism of the Muc1 gene on litter size of pigs

An investigation was undertaken to study the association between the variable number of tandem repeats polymorphism of the Muc1 gene and the litter size in pigs. Four different alleles were found in three breeds. The sequence analysis shows that the repetitive region of pig Muc1 gene is an array of 108-bp repeats. A total of 2,430 litter records from 897 sows genotyped at Muc1 gene were used to analyze the total number born (TNB) and number born alive (NBA). The study of the effects on litter size suggests that TNB and NBA of genotype AA are the highest in Large White, and the TNB and NBA of the third to ninth parities are 1.61 and 2.29 piglets per litter higher (P < 0.05) than those of the genotype DD, respectively. In Landrace, TNB and NBA of the genotype AA are 1.68 (P < 0.01) and 1.58 (P < 0.05) piglets per litter higher than those of the BB genotype in the third to ninth parities, but for all parities the TNB of genotype AA were 0.76 piglets per litter (P < 0.05) higher than BB. In Duroc, the TNB and NBA of genotype AA are about 1.5 piglets per litter more than those of DD in the third to ninth parities, though not significantly. The research suggests that the smaller allele tends to have higher litter size. The results indicate that Muc1 gene is significantly associated with litter size in pigs.     

Effect of polymorphism in the peroxisome proliferator-activated receptor gamma gene on litter size of pigs

The association of polymorphisms in peroxisome proliferator-activated receptor γ (PPARγ) gene with litter size was studied in Large White and Landrace pig. Three SNP loci (P1, P2 and P7) on PPARγ₂ gene were determined by PCR–SSCP and the results showed that there were A → G mutations at 220 and 324 bp in 5′-regulator region and at 147 bp in exon 6, respectively. Allele frequencies were analysed in two breeds. Information on 2341 litter records from 564 sows was used to analyse the trait total number born (TNB) and number born alive (NBA). In Large White, TNB and NBA of genotype BB for P2 locus were the lowest, and the TNB and NBA of third and following parities and all parities were 0.74 and 0.51 piglets per litter less (P < 0.001) than those of the highest genotype AB, respectively, but for P1 and P7 locus the beneficial genotype AA were more 0.4–0.8 piglets per litter (P < 0.05) than the inferior genotype AB. In landrace, TNB and NBA of the first parity of genotype BB for P1 locus were 2.0 piglets per litter higher than AA (P < 0.05), but for all parities the TNB and NBA of genotype BB were 0.66 and 0.97 piglets per litter (P < 0.05) higher than AA, respectively. At P2 locus, the TNB and NBA of the second parity of genotype AA were obviously higher than those of AB (P < 0.05). And at P7 locus, the TNB and NBA of each parity of genotype AA were both about 2 piglets per litter more than those of BB (P < 0.05). The results indicated that PPARγ gene was significantly associated with litter size in pigs.     

Arachidonate 15-lipoxygenase and ubiquitin as fertility markers in boars

Accurate semen analysis is an important issue in the swine industry. We evaluated two candidate fertility marker proteins associated with sperm cytoplasmic droplet (CD), including 15-lipoxygenase (15-LOX) and ubiquitin (UBI) in a controlled single-sire artificial insemination (AI) trial. Ejaculates (n=116) were collected from 18 fertile Large White boars monthly for 8 mo, and analyzed by semi-quantitative, densitometry-based Western blotting and flow cytometry with antibodies against 15-LOX and UBI. Data were correlated with farrowing rates (FR) and total numbers of piglets born (TNB) from 1754 AI services by 13 of 18 boars, and compared with a conventional microscopic semen analysis. In semi-quantitative Western blotting, both 15-LOX and UBI were correlated with seasonal changes in the percentage of normal (r=-0.38, P<0.01; r=-0.27, P<0.05, respectively) and CD-bearing spermatozoa (r=0.35, P<0.01; r=0.27, P<0.05, respectively). In flow cytometry, UBI and 15-LOX levels showed seasonal changes coinciding with seasonal changes of FR and TNB, representing 13 boars, 88 ejaculates and 1,232 AI services. There were correlations between flow cytometric values of UBI and FR (r=0.31; P<0.05), adjusted FR (r=0.30; P<0.05), TNB (r=-0.38; P<0.01) and adjusted TNB (r=-0.37; P<0.01). Flow cytometric measurements of 15-LOX correlated negatively with TNB (r=-0.33; P<0.05) and adjusted TNB (r=-0.34; P<0.05). These data suggested that boar fertility estimation could be achieved within a group of fertile boars by the use of objectively measurable fertility markers. Flow cytometry appeared more informative and more practical than semi-quantitative Western blotting. This technology could be further optimized for the selection of the most fertile sires in an artificial insemination program.     

Single step genome-wide association studies based on genotyping by sequence data reveals novel loci for the litter traits of domestic pigs

In this study, data genotyping by sequence (GBS) was used to perform single step GWAS (ssGWAS) to identify SNPs associated with the litter traits in domestic pigs and search for candidate genes in the region of significant SNPs. After quality control, 167,355 high-quality SNPs from 532 pigs were obtained. Phenotypic traits on 2112 gilt litters from 532 pigs were recorded including total number born (TNB), number born alive (NBA), and litter weight born alive (LWB). A single-step genomic BLUP approach (ssGBLUP) was used to implement the genome-wide association analysis at a 5% genome-wide significance level. A total of 8, 23 and 20 significant SNPs were associated with TNB, NBA, and LWB, respectively, and these significant SNPs accounted for 62.78%, 79.75%, and 58.79% of genetic variance. Furthermore, 1 (SSC14: 16314857), 4 (SSC1: 81986236, SSC1: 66599775, SSC1: 161999013, and SSC1: 267883107), and 5 (SSC9: 29030061, SSC2: 32368561, SSC5: 110375350, SSC13: 45619882 and SSC13: 45647829) significant SNPs for TNB, NBA, and LWB were inferred to be novel loci. At SSC1, the AIM1 and FOXO3 genes were found to be associated with NBA; these genes increase ovarian reproductive capacity and follicle number and decrease gonadotropin levels. The genes SLC36A4 and INTU are involved in cell growth, cytogenesis and development were found to be associated with LWB. These significant SNPs can be used as an indication for regions in the Sus scrofa genome for variability in litter traits, but further studies are expected to confirm causative mutations.     

MyoG基因对金华猪繁殖性状的影响

用PCR-RFLP方法对金华猪I系（109头）、II系（15头）、III系（25头）的MyoG基因的第二内含子内（PCR1- MspⅠ-RFLP）和3'-端（PCR2- MspⅠ-RFLP）位点进行了多态性分析。结果表明：PCR1- MspⅠ-RFLP位点有3种基因型（AA、AB、BB）,其基因型频率分别为0.1544,0.3826,0.4631;PCR2- MspⅠ-RFLP位点只有2种基因型（MM、MN）,其基因型频率分别为0.9953和0.0047。采用SPSS程序分析MyoG基因对金华猪繁殖性状的影响。结果表明：MyoG基因对金华母猪初胎的总产仔数、二胎的产活仔数影响显著（P<0.05）,而对其他胎次组合的总产仔数、产活仔数以及初生窝重没有显著影响（P<0.05）。     

5个与猪产仔数相关基因的效应分析

为了比较不同基因对猪产仔数效应大小,在相同的大白 （158头）、长白 （224头）猪群中采用PCR-RFLP法进行了ESR、FSHβ、PRL、PRLR、NCOA1 5种与产仔数相关基因的基因型频率检测及不同基因型的总产仔数和产活仔数效应分析,结果表明,对相同母猪群产仔数影响效应最大的是PRLR和NCOA1基因,AA型比BB型母猪总产仔数高2.28~3.33头（P<0.01）,产活仔数高1.57~3.30头（P<0.01）,其次为ESR和FSHβ基因,BB型比AA型母猪总产仔数高0.55~1.18头（P<0.05,长白例外）,产活仔数高0.37~1.20头（P<0.05）。PRL基因对产仔数效应不显著。     

Effect of polymorphism in the leukemia inhibitory factor gene on litter size in Large White pigs

DNA polymorphism of the porcine leukemia inhibitory factory (LIF) was investigated and used to study the effects on litter size in Large White pigs. A total of 2,167 litter records from 420 sows genotyped at two SNP loci (LIF1 and LIF2) within LIF gene were analyzed to determine whether LIF influenced total number born (TNB) and number born alive (NBA). The results indicated that B allele at LIF1 locus and A allele at LIF2 locus seem to have advantageous effects on litter size. However, the combined analyzed results demonstrated that genotype AAAA, ABBB, and BBBB are better than genotype AAAB, AABB, and ABAB for TNB and NBA in either third to eighth parity or all parities. In all parities, the sows with AAAA genotype had an advantage of 1.76 piglets (P < 0.001) for TNB and 1.44 piglets (P < 0.01) for NBA per litter over the AAAB sows, respectively. The results in this study demonstrated that LIF gene was significantly associated with litter size in pigs. H. C. Lin and G. F. Liu contributed equally to this work.     

Study on the Association Between Estrogen Receptor Gene (ESR) and Reproduction Traits in Landrace Pigs

To study the potential use of estrogen receptor gene (ESR) as a genetic marker to improve the reproductive traits of pigs, the genotypes of the ESR PCR product digested by Pvu II were determined in 2 239 litters from 612 Landrace sows. The data of the first, second, and later parities were separately evaluated. Although the frequency of the B allele was much lower than that of the A allele, likelihood ratio test showed that the gene frequencies were in Hardy-Weinberg equilibrium. The effects of ESR of different parities were not equal. In summary, the sows with the BB genotype showed better performance for total number of piglets born (TNB) and number of piglets born alive (NBA), but had a lower average piglet weight at birth (AWB). It was concluded that ESR could be used as a marker for the selection of litter size in the Landrace population.     

Pig melatonin receptor 1a (MTNR1A) genotype is associated with seasonal variation of sow litter size

The duration of nocturnal melatonin secretion reaches its minimum in summer, a physiological event that is likely related with the diminished sow fertility and delayed puberty typically observed in this season. Melatonin exerts its function by binding two different receptors named as MTNR1A and MTNR1B. Interestingly, the MTNR1A gene is located on a chromosome SSC17 region where QTL for prolificacy traits have been detected in previous studies. In this work, we have found a synonymous T162C polymorphism at exon 2 of the pig MTNR1A gene. An association analysis between this polymorphism and sow prolificacy in an Iberian ×  Meishan intercross was performed. The utilization of four statistical models of increasing complexity demonstrated that the MTNR1A gene has both additive and dominant effects on total number of born piglets (TNB) and number of piglets born alive (NBA). Additive effects were significant in summer (TNB, P < 0.01; NBA, P < 0.001), whereas dominant effects reached significance both in fall (TNB, P < 0.01; NBA, P < 0.05) and in winter (TNB, P < 0.001; NBA, P < 0.05). The seasonal variation observed for MTNR1A additive and dominant effects might be produced by the influence of photoperiod on the pattern and duration of melatonin secretion. These results illustrate that the complex interaction between genotype and environment can be an important source of phenotypic variation of reproductive traits.     

Consequences of timing of organic enrichment provision on pig performance,health and stress resilience after weaning and regrouping

Most pigs in slatted systems are provided with enrichment meeting only minimum legal requirements. We aimed to explore the effects of a novel enrichment treatment consisting of daily provided fodder beet and jute bags for pigs in slatted systems, and investigate the timing of enrichment provision on performance, health and stress resilience. We used 280 weaners allocated into standard (S, meeting only legal requirements consisting of a plastic toy and softwood) or enriched (E) treatment (n = 14 groups/treatment). At regrouping during the grower to finisher transition, pigs were either kept in the same treatment (EE, SS) or switched from enriched to standard (ES) and vice versa (SE); each treatment was replicated on five groups. Pigs were weighted at the start and end of weaner, and finisher stage, and feed intake was recorded. Occurrence of scouring, respiratory problems, locomotor disorders, tail, ear, and body lesions were recorded twice a week. Ten males per treatment were sampled for saliva on days 1, 2 and 4, either postweaning or after the housing switch. Saliva samples were analysed for cortisol, alpha-amylase, haptoglobin (Hp), and adenosine deaminase. Additionally, these pigs were sampled for hair at the start and end of weaner, and end of finisher stage to analyse for hair cortisol and cortisone. We found that E weaners consumed less feed (P = 0.04), had better FCR (feed conversion ratio, P = 0.03) and less ear lesions for two weeks postweaning (P = 0.04), and tended to have lower occurrence of scouring (P = 0.07) and higher salivary cortisol concentrations (P = 0.09) than S weaners. Effects of enrichment treatment during weaner stage on performance were carried through to finisher stage, with EE and ES pigs having better FCR (P = 0.0009) and higher BW (P = 0.0001) compared to SS and SE pigs. E treatment during finisher stage decreased feed intake (P = 0.04) and tended to decrease Hp levels (P = 0.07). There was a significant interaction between enrichment treatments during weaner and finisher stages on finisher body lesions: EE finishers had less lesions than SS, ES, and SE finishers (P = 0.04). There were no other significant differences caused either by enrichment treatment during weaner/finisher stage or their interaction. We conclude that the novel enrichment applied at weaner stage had positive effects on ear lesions and performance, which were carried through to finisher stage. Body lesions were affected by its application during both stages, with finishers receiving the enrichment treatment throughout (EE) having reduced body lesions than the rest of the finishers.     

北京黑猪FSHb 亚基基因的多态性与繁殖性状的关联分析

本研究以北京黑猪为研究对象, 以FSHb 亚基基因为产仔性状的候选基因, 分别采用PCR产物直接电泳和PCR-RFLP方法来检测FSHβ亚基基因2个位点的多态性。结合测序发现: FSHb-1位点上, 北京黑猪BB型的134与135 bp (D00621序列的6 473与6 474 bp) 之间插入273 bp的片段而产生多态, 序列分析表明该插入片段为一典型的逆转座子, 在插入片段中还发现了一个RNA 聚合酶Ⅲ内部启动子; FSHb-2位点上, 由于扩增片段173 bp处存在C→T的突变, 使得HaeⅢ酶切位点消失而产生多态; 2个位点的A、B等位基因在北京黑猪群体中都有分布, 且处于低度多态。χ2适合性检验结果表明, 该群体在这2个位点的突变都达到Hardy-Weinberg平衡状态 (P>0.05)。用SAS 8.2 软件最小二乘法拟合线性模型, 将基因座不同基因型与繁殖性状总产仔数 (TNB)、产活仔数 (NBA) 和出生重 (WB) 进行了关联分析, 结果表明: 就初产母猪而言, FSHb-1位点上, AA型比AB和BB型个体的TNB分别多0.96头和1.85头 (P＜0.05), AA和AB型比BB型个体的NBA分别多0.95头和1.69头(P＜0.05)。FSHb-2位点上, AA型比AB型和BB型个体的TNB分别多1.57头和2.15头 (P＜0.05); AA和AB型比BB型个体的NBA分别多1.00头和0.94头 (P＜0.05); 就经产母猪而言, FSHb-2位点上, AA型个体的WB比BB型的WB重0.25 kg (P＜0.05)。全部群体的FSHb-1位点的A等位基因和初产母猪FSHb-2位点的A等位基因对TNB、NBA和WB表现为正效应。     

Effects of soybean isoflavones on the growth performance,intestinal morphology and antioxidative properties in pigs

Soybean meal is rich in soybean isoflavones, which exhibit antioxidant, anti-inflammatory, antiviral and anticancer functions in humans and animals. This study was conducted to investigate the effects of soybean isoflavones on the growth performance, intestinal morphology and antioxidative properties in pigs. A total of 72 weaned piglets (7.45 ± 0.13 kg; 36 males and 36 females) were allocated into three treatments and fed corn-soybean meal (C-SBM), corn-soy protein concentrate (C-SPC) or C-SPC supplemented with equal levels of the isoflavones found in the C-SBM diet (C-SPC + ISF) for a 72-day trial. Each treatment had six replicates and four piglets per replicate, half male and half female. On day 42, one male pig from each replicate was selected and euthanized to collect intestinal samples. The results showed that compared to pigs fed the C-SPC diet, pigs fed the C-SBM and C-SPC + ISF diets had higher BW on day 72 (P < 0.05); pigs fed the C-SBM diet had significantly higher average daily gain (ADG) during days 14 to 28 (P < 0.05), with C-SPC + ISF being intermediate; pigs fed the C-SBM diet tended to have higher ADG during days 42 to 72 (P = 0.063), while pigs fed the C-SPC + ISF diet had significantly higher ADG during days 42 to 72 (P < 0.05). Moreover, compared to pigs fed the C-SPC diet, pigs fed the C-SBM diet tended to have greater villus height (P = 0.092), while pigs fed the C-SPC + ISF diet had significantly greater villus height (P < 0.05); pigs fed the C-SBM and C-SPC + ISF diets had significantly increased villus height-to-crypt depth ratio (P < 0.05). Compared with the C-SPC diet, dietary C-SPC + ISF tended to increase plasma superoxide dismutase activity on days 28 (P = 0.085) and 42 (P = 0.075) and reduce plasma malondialdehyde (MDA) content on day 42 (P = 0.089), as well as significantly decreased jejunal mucosa MDA content on day 42 (P < 0.05). However, no significant difference in the expression of tight junction genes among the three groups was found (P > 0.05). In conclusion, our results suggest that a long-term exposure to soybean isoflavones enhances the growth performance, protects the intestinal morphology and improves the antioxidative properties in pigs.     

Genome-wide association studies uncover genes associated with litter traits in the pig

Litter traits are critical economic variables in the pig industry as they represent a production indicator that can serve to determine sow fertility. In this study, a genome-wide association study on litter traits, including total number born (TNB), number born alive (NBA), litter birth weight (LBW), average birth weight (ABW), and piglet uniformity (PU), was carried out on two pig breeds (Yorkshire and Landrace). A total of 3 637 pigs of both breeds were genotyped using the GeneSeek GGP Porcine 50K SNP BeadChip. A mixed linear model (MLM) and fixed and random model circulating probability unification (FarmCPU) were employed in the genome-wide association studies for litter traits using combined data from the two pig breeds and data from each breed separately. Additionally, the heritability of traits was estimated using three methods—pedigree-based best linear unbiased prediction (PBLUP), genomic best linear unbiased prediction (GBLUP), and single-step best linear unbiased prediction (ssGBLUP)—and was found to lie between 0.065 and 0.1289, 0.0478 and 0.0938, 0.0793 and 0.0935, 0.1862 and 0.2163, and 0.0327 and 0.0419 for TNB, NBA, LBW, ABW, and PU, respectively. We also compared the genomic prediction accuracies and unbiasedness for litter traits of the three BLUP models. Our results indicated that the ssGBLUP method provided higher predictive accuracies and more rational unbiasedness compared with the PBLUP and GBLUP methodologies. Furthermore, based on their possible roles, eight candidate genes (INHBA, LEPR, HDHD2, CTNND2, RNF216, HMX1, PAPPA2, and NTN1) were identified as being linked with litter traits. In the middle of the test, these genes were found to be connected with pig metabolism and ovulation rate. Our results provide the insights into the genetic architecture of litter traits in pigs, and the potential single nucleotide polymorphisms (SNPs) and candidate genes identified may benefit economic profits in pig-breeding industry and contribute to improve litter traits.     

Nonlinear analysis of heart rate variability for evaluating the growing pig stress response to an acute heat episode

Heart rate variability (HRV) is a proxy measure of autonomic function and can be used as an indicator of swine stress. While traditional linear measures are used to distinguish between stressed and unstressed treatments, inclusion of nonlinear HRV measures that evaluate data structure and organization shows promise for improving HRV interpretation. The objective of this study was to evaluate the inclusion of nonlinear HRV measures in response to an acute heat episode. Twenty 12- to 14-week-old growing pigs were individually housed for 7 days and acclimated to thermoneutral conditions (20.35°C ± 0.01°C; 67.6% ± 0.2% RH) before undergoing one of the two treatments: (1) thermoneutral control (TN; n = 10 pigs) or (2) acute heat stress (HS; n = 10 pigs; 32.6°C ± 0.1°C; 26.2% ± 0.1% RH). In Phase 1 of the experimental procedure (P1; 60 min), pigs underwent a baseline HRV measurement period in thermoneutral conditions before treatment [Phase 2; P2; 60 min once gastrointestinal temperature (T_g) reached 40.6°C], where HS pigs were exposed to heated conditions and TN pigs remained in thermoneutral conditions. After P2, all pigs were moved back to thermoneutral conditions (Phase 3; P3; 60 min). During each phase, T_g data were collected every 5 min and behavioural data were collected to evaluate the amount of time each pig spent in an active posture. Additionally, linear (time and frequency domain) and nonlinear [sample entropy (SampEn), de-trended fluctuation analysis, percentage recurrence, percentage determinism (%DET), mean diagonal line length in a recurrence plot] HRV measures were quantified. Heat stressed pigs exhibited greater T_g (P = 0.002) and spent less time in an active posture compared to TN pigs during P2 (P = 0.0003). Additionally, low frequency to high frequency ratio was greater in HS pigs during P3 compared to TN pigs (P = 0.02). SampEn was reduced in HS pigs during P2 (P = 0.01) and P3 (P = 0.03) compared to TN pigs. Heat stressed pigs exhibited greater %DET during P3 (P = 0.03) and tended to have greater %DET (P = 0.09) during P2 than TN pigs. No differences between treatments were detected for the remaining HRV measures. In conclusion, linear HRV measures were largely unchanged during P2. However, changes to SampEn and %DET suggest increased heat stress as a result of the acute heat episode. Future work should continue to evaluate the benefits of including nonlinear HRV measures in HRV analysis of swine heat stress.     

Growth,blood, carcass and meat quality traits from local pig breeds and their crosses

Contrary to intensive pig production, local pig breeds and their production systems are able to respond to the high criteria and expectations of modern society in regard to some environmental aspects, animal welfare, food quality and healthiness. This study proposes the recovery, study and use of a cross between two local breeds, contributing to animal biodiversity conservation and to the income of local pig producers. This work studied the growth performance and blood, carcass and meat quality traits of Alentejano (AL), Bísaro (BI) and Ribatejano (RI) (AL × BI, BI × AL) castrated male pigs. Raised outdoors, pigs were fed commercial diets ad libitum and killed at ~65 kg (trial 1, n = 10 from each genotype) and ~150 kg BW (trial 2, n = 9 from each genotype). In trial 1, AL and AL × BI attained slaughter weight later than BI and BI × AL pigs, with AL presenting lower average daily gains than the other genotypes (P < 0.001). Alentejano and RI pigs presented higher (P < 0.01) levels of plasma total protein than BI. Overall, carcass traits were affected by genotype, with length (P < 0.01), yield (P = 0.07) and lean cut proportions (P < 0.01) lower in AL than BI, and intermediate values for crossed pigs. Conversely, AL pigs presented higher fat cut proportion (P < 0.01), average backfat thickness (P < 0.001) and ‘zwei punkte’ fat depth (P < 0.01) than BI and RI pigs. Alentejano pigs also presented higher Longissimus lumborum (LL) intramuscular fat (P < 0.05), myoglobin content and ultimate pH (P < 0.01), but lower total collagen (P < 0.05), drip (P < 0.001) and cooking losses (P < 0.01), and shear force (P < 0.001) than all other genotypes. Finally, LL showed a more intense red colour in AL than in BI pigs. In trial 2, AL pigs confirmed to be a slow-growing obese breed with lower bone and lean cut proportions than BI, and higher LL intramuscular fat, richer colour, lower water loss and higher tenderness. In both trials, RI pigs grew faster, with higher lean and lower fat cut proportions and backfat thickness, and with overall LL characteristics comparable to those observed in AL pigs. This work demonstrates some clear differences between AL and BI breeds while showing that their crosses present intermediate characteristics in most studied traits. These data on RI pigs can be useful to breeders’ associations and farmers in order to consider the use of these crosses as an option or complement to pure line breeding.     

Health-promoting effects of Lactobacillus-fermented barley in weaned pigs challenged with Escherichia coli K88 +

Fermented feeds are being considered as practical alternatives to antimicrobial growth promoters (AGP) supplemented in nursery pig diets. This study aimed to investigate health-promoting effects of fermented barley in weaned pigs challenged with Escherichia coli K88 ⁺. A total of 37 piglets were weaned at 21 ± 1 day of age (6.41 ± 0.47 kg of BW) and assigned to either of the following five treatment groups: (1) unchallenged control (UCC; n = 7), (2) challenged control (CC; n = 7), (3) AGP (CC + 0.1% AGP; n = 7), (4) Ferm1 (challenged and fed homofermentative Lactobacillus plantarum (Homo)-fermented barley; n = 8) and (5) Ferm2 (challenged and fed heterofermentative L. buchneri (Hetero)-fermented barley; n = 8). The control diet included unfermented barley. Barley was fermented with either Homo or Hetero for 90 days under anaerobic conditions. On day 10, all pigs except those in UCC group were orally inoculated with E. coli K88 ⁺ (6 × 10⁹ colony forming units/ml). The pre-planned orthogonal test was performed to compare (1) UCC and CC, (2) CC and AGP, (3) CC and Ferm1 + Ferm2, as well as (4) Ferm1 and Ferm2. Challenged control pigs showed shorter (P < 0.05) villus height (VH) in the duodenum and deeper (P < 0.05) crypt depth (CD) in the jejunum than UCC pigs. The AGP group had higher (P < 0.05) VH and lower (P < 0.05) IL-6 gene expression in the jejunum compared with CC group. Compared to CC, Ferm1 and Ferm2 had decreased (P < 0.05) CD in the duodenum, IL-6 gene expression in the jejunum and rectal temperature at 24 h post-challenge. Pigs fed fermented barley diets showed greater (P < 0.05) faecal abundance of Clostridium Cluster IV and Lactobacilli than those fed UCC diet. Ferm2-fed pigs showed lower (P < 0.05) concentrations of band cells, eosinophils and lymphocytes at 6, 24 and 48 h after challenge, respectively, and lower (P < 0.05) faecal abundance of Enterobacteriaceae 24 h after challenge than the Ferm1-fed pigs. In conclusion, the substitution of unfermented barley with fermented barley in a nursery diet showed similar results as those shown by AGP supplementation in terms of enhancing the intestinal morphology and modulating faecal microbiota composition, as well as down-regulating the pro-inflammatory cytokines; therefore, fermented barley can be a possible nutritional strategy for managing nursery pigs fed diets without in-feed AGP.     

SLA-11 mutations are associated with litter size traits in Large White and Chinese DIV pigs

Litter size is an important economic traits in pigs. SLA-11 gene is a member of SLA (swine leukocyte antigen) complex. In our previous study, the SLA-11 gene was differentially expressed in PMSG-hCG stimulated preovulatory ovarian follicles of Chinese Taihu and Large White sows. Here, we identified two mutations (c.754-132 T?>?C and c.1421?+?38 T?>?C) in SLA-11 gene and analyzed the associations of two SNPs with litter size traits in Large White (n?=?263) and DIV (n?=?117) sows. The results showed that in Large White pigs, SLA-11 c.754-132?CC sows produced 0.74 and 0.87 more pigs per litter for TNB and NBA of all parities than did TT sows (p?<?.05); In DIV pigs, SLA-11 c.754-132?CC sows produced 1.17 more pigs per litter for TNB of all parities than did TC sows (p?<?.05). In Large White pigs, SLA-11 c.1421?+?38?CC sows produced 0.9 more pigs per litter for TNB of all parities than did TT sows (p?<?.05), while in DIV pigs SLA-11 c.1421?+?38?CC sows produced 0.84 and 0.7 less pigs per litter for TNB and NBA of all parities than did TT sows (p?<?.05). Our research indicated that SLA-11 mutations were potential molecular markers for improving the litter size traits in pigs.     

Effects of rapid temperature fluctuations prior to breeding on reproductive efficiency in replacement gilts

Rapidly cooling pigs after heat stress (HS) results in a pathophysiological condition, and because rapid temperature fluctuations may be associated with reduced reproductive success in sows, it lends itself to the hypothesis that these conditions may be linked. Objectives were to determine the effects of rapid cooling on thermal response and future reproductive success in pigs. Thirty-six replacement gilts (137.8±0.9 kg BW) were estrus synchronized and then 14.1±0.4 d after estrus confirmation, pigs were exposed to thermoneutral conditions (TN; n=12; 19.7±0.9°C) for 6 h, or HS (36.3±0.5°C) for 3 h, followed by 3 h of rapid cooling (HSRC; n=12; immediate TN exposure and water dousing) or gradual cooling (HSGC; n=12; gradual decrease to TN conditions) repeated over 2 d. Vaginal (T_V) and gastrointestinal tract temperatures (T_GI) were obtained every 15 min, and blood was collected on d 1 and d 2 during the HS and recovery periods at 180 and 60 min, respectively. Pigs were bred 8.3±0.8 d after thermal treatments over 2 d. Reproductive tracts were collected and total fetus number and viability were recorded 28.0±0.8 d after insemination. HS increased T_V and T_GI (P=0.01; 0.98 °C) in HSRC and HSGC compared to TN pigs. During recovery, T_V was reduced from 15 to 105 min (P=0.01; 0.33 °C) in HSRC compared to HSGC pigs, but no overall differences in T_GI were detected (P<0.05; 39.67 °C). Rapid cooling increased (P<0.05) TNFα compared to HSGC and TN pigs during recovery-d 1 (55.2%), HS-d 2 (35.1%), and recovery-d 2 (64.9%). Viable fetuses tended to be reduced (P=0.08; 10.5%) and moribund fetuses tended to be increased (P=0.09; 159.3%) in HSRC compared to HSGC and TN pigs. In summary, rapid cooling prior to breeding may contribute to reduced fetal viability and reproductive success in pigs.     

Transient effect of single or repeated acute deoxynivalenol and zearalenone dietary challenge on fecal microbiota composition in female finishing pigs

Mycotoxins are a major contaminant of pig feed and have negative effects on health and performance. The present study investigated the impact of single or repeated acute challenges with a diet naturally contaminated with deoxynivalenol (DON) and zearalenone (ZEN) on growth performances of finishing pigs and their fecal microbiota composition. A total of 160 pigs (castrated males and females) in two successive batches were randomly divided into four experimental groups of 40 pigs each. The control group received a control finisher diet from 99 to 154 days of age. Challenged groups were subjected to a 7-day acute challenge by being fed a DON- and ZEN-contaminated diet (3.02 mg DON/kg feed and 0.76 mg ZEN/kg feed) at 113 days (group DC), 134 days (group CD) or both 113 and 134 days (group DD). Microbiota composition was analyzed via 16S rRNA sequencing from fecal samples collected from the 80 females at 99, 119, 140 and 154 days. Challenged pigs (i.e. groups DC, CD and DD) reduced their average daily feed intake by 25% and 27% (P < 0.001) and feed efficiency by 34% and 28% (P < 0.05) during the first and second mycotoxin exposure, respectively. Microbiota composition was affected by mycotoxin exposure (P = 0.07 during the first exposure and P = 0.01 during the second exposure). At the family level, mycotoxin exposure significantly (P < 0.05) decreased the relative abundances of Ruminococcaceae, Streptococcaceae and Veillonellaceae and increased that of Erysipelotrichaceae at both 119 and 140 days of age. After the 7-day DON/ZEN challenge, the relative abundance of 6 to 148 operational taxonomic units (OTUs) differed among the treatment groups. However, none of these OTUs changed in all treatment groups. Using 27 functional pathways, pigs exposed to DON/ZEN challenges could be distinguished from control pigs using sparse partial least squares discriminant analysis, with a 15% misclassification rate. Regarding the functionality of these predictors, two pathways were involved in detoxifying mycotoxins: drug metabolism and xenobiotic metabolism by cytochrome P450. In challenged pigs, microbiota composition returned to the initial state within 3 weeks after the end of a single or repeated DON/ZEN challenge, highlighting the resilience of the gut microbiome. The feeding and growth performances of the pigs during challenge periods were significantly correlated with biological pathways related to health problems and modifications in host metabolism. To conclude, short-term DON/ZEN challenges resulted in transient modifications in the composition and functions of fecal microbiota.