Saving genetic resources of native pigs in Occidental and Oriental countries - practical examples of the characterization and utilization of native pigs in Hungary and Laos

Feeding Ractopamine Improves the Growth Performance and Carcass Characteristics of the Lard-Type Mangalica Pig

Mangalica pigs are gaining popularity within the U.S. as a niche breed, given their reputation for superior-quality pork. However, slow growth rates, a poor lean yield, and excessive adiposity limit the widespread adoption of Mangalica. To determine if feeding the metabolic modifier, ractopamine hydrochloride (RAC), would improve growth performance without impairing pork quality in the Mangalica, pigs were fed either 0 or 20 mg per kg RAC for 21 days. At 24 h postharvest, pork quality and carcass composition measurements were recorded; then, primal cuts were fabricated and assessed. RAC increased ADG (p < 0.04) and gain efficiency (p < 0.03) by 24% and 21%, respectively. RAC increased Loin Eye Area (p < 0.0001) by 21% but did not impact the 10th rib fat depth (p > 0.90) or marbling score (p > 0.77). RAC failed to alter any primal cut weights. Feeding RAC lowered b* values (p < 0.04) and tended to lower L* values (p < 0.08) while not affecting a* values (p > 0.30), suggesting RAC darkened loin color. Finally, RAC decreased cook yield percentage (p < 0.02) by 11% without impacting Warner-Bratzler Shear Force (p > 0.31). These data support the hypothesis that feeding RAC to Mangalica improves growth performance without impairing pork quality in this breed.

The Role of lncRNAs in Pig Muscle in Response to Cold Exposure

Cold exposure is an essential factor affecting breeding efforts in cold regions. Muscle, as an important tissue for homeothermic animals, can produce heat through shivering thermogenesis (ST) and non-shivering thermogenesis (NST) under cold exposure. Long non-coding RNAs (lncRNAs) play important roles in regulating gene expression. However, the regulatory mechanisms of lncRNAs and their role in the thermogenesis of pigs are unclear. We examined lncRNAs in the skeletal muscle of an indigenous pig breed, the Enshi black pig, when the pigs were exposed to acute or chronic cold. Three pigs were maintained inside a pig house (control group), three pigs were maintained outside the pig house for 55 d (chronic cold group), and three pigs were suddenly exposed to the conditions outside the pig house for 3 days (acute cold group). After the experiment, the longissimus dorsi of each pig were collected, and their lncRNA profiles were sequenced and analyzed. Each sample obtained nearly 12.56 Gb of clean data. A total of 11,605 non-coding RNAs were obtained, including 10,802 novel lncRNAs. The number of differentially expressed lncRNAs (DElncRNAs) was identified under acute cold (427) and cold acclimation (376), with 215 and 192 upregulated lncRNAs, respectively. However, only 113 lncRNAs were commonly upregulated by acute cold and cold acclimation. In addition, 65% of the target genes were trans-regulated by DElncRNAs. The target genes were enriched in signal transduction, immune system, cell growth and death pathways, and amino acid and carbohydrate metabolism. Compared to cold acclimation, acute cold stress-induced more DElncRNAs and response pathways. In conclusion, low temperatures altered the expression levels of lncRNAs and their target genes in muscle tissue. Some potential mechanisms were revealed, including ion migration and the metabolism of amino acids and carbohydrates.

Characterization of Growth Performance, Pork Quality, and Body Composition in Mangalica Pigs

European heritage breeds, such as the Blonde (B), Red (R), and Swallow-bellied (SB) Mangalica pig, display an extreme propensity to fatten and are reputed to produce superior quality pork. This suggests that Mangalica pork should command a higher price, and the Mangalica is a candidate breed to target niche markets within the United States. Our objectives were to test this hypothesis by (1) directly comparing growth performance and carcass merit of purebred Yorkshire (Y), B, R, and SB Mangalica pigs to identify the best breed for adoption, and (2) comparing indices of pork quality in purebred R, Y, and crossbred (R × Y) pigs to determine if crossbreeding represented a viable alternative to the adoption of purebred Mangalica. Daily feed intake, average daily gain (ADG), and feed efficiency were highest in Y and lowest in SB pigs with B and R ranked intermediately (p < 0.001). Backfat thickness was greatest in B and lowest in Y with R and SB ranked intermediately (p < 0.001). Marbling score was greatest in R pigs and lowest in Y pigs with B and SB ranked intermediately (p < 0.01). In contrast, loin eye area (LEA) was greatest in Y pigs compared to B, R, and SB (p < 0.001). Indices of meat quality were then compared in R, R × Y, and Y pigs. Backfat thickness and marbling scores were greater in R than R × Y and Y pigs (p < 0.001) while LEA was greater in Y than R × Y and R pigs (p < 0.001). Loin and ham ultimate pH, color, and firmness scores were significantly greater in R than R × Y or Y pigs (p < 0.05). Meanwhile, cook loss was significantly less in R than Y pigs (p < 0.007) while Warner-Bratzler Shear Force (WBS) was not different in chops between groups (p < 0.11). These data indicate that though Mangalica exhibit poorer growth performance, Mangalica pork exhibits superior pork quality attributes, suggesting that higher price points for Mangalica pork in niche markets are justified.

Cryopreservation of immature oocytes of the indigeneous Vietnamese Ban Pig

We report the cryopreservation of oocytes from Ban miniature pigs which are endemic in Vietnam. Immature cumulus-oocyte complexes were collected from antral follicles of 7-8 mo old female cyclic Ban pigs and vitrified in micro-drops. Oocyte morphology, lipid content, post-warming survival, nuclear maturation, and embryo development were compared to those of oocytes from commercially slaughtered Landrace × Large white hybrid pigs. The size of oocytes in the two breeds was similar. However, significantly lower amounts of intracellular lipid were detected in Ban oocytes. There was no difference (p > 0.05) between Ban and Landrace × Large white oocytes in percentages of post-warming survival (93.1 ± 3.4% vs. 70.7 ± 16.7%, respectively) and nuclear maturation after in vitro maturation (80.4 ± 5.1% vs. 90.0 ± 1.3% respectively). Similarly, cleavage (30.8 ± 7.8% vs. 10.3 ± 6.1%, respectively) and blastocyst development rates (9.4 ± 5.0% vs. 0.79 ± 0.79, respectively) were not different (p > 0.05) between vitrified Ban and Landrace × Large white oocytes after in vitro fertilization and embryo culture. In conclusion, high survival and maturation rates were achieved after vitrification of immature Ban oocytes and their cryo-tolerance was similar to that of Landrace × Large white oocytes, despite the difference in lipid content. We succeeded to generate reasonable rates of blastocysts from vitrified Ban oocytes by in vitro fertilization.

Optimization of the in vitro fertilization protocol for frozen epididymal sperm with low fertilization ability in Ban-A native Vietnamese pigs

The aim of the present study was to improve the penetration during in vitro fertilization (IVF) of a frozen lot of epididymal sperm with a notoriously low fertilization ability of a Ban boar which is a native Vietnamese breed by optimizing different parameters of the IVF system. In Experiment 1, we determined that Pig-fertilization medium was superior medium to Tyrode's albumin lactate pyruvate-polyvinyl alcohol medium for IVF and defined the optimum the sperm concentration (1 × 10⁶  sperm/ml). In Experiment 2, we clarified that partial removal of cumulus cells from cumulus-oocyte complexes by hyaluronidase treatment before IVF enhances sperm penetration, whereas complete cumulus removal reduces penetration. Finally, in Experiment 3 the elevation of concentration of caffeine in Pig-fertilization medium from 2 to 5 mmol/L and the prolongation of the co-culture of gametes from 3 to 5 hr significantly increased the total penetration rate from 15.2% to over 50%. In conclusion, the combination of partial oocyte denudation, an elevated caffeine concentration in Pig-fertilization medium and an extended interval of IVF with using an optimized sperm concentration was a potent way to improve the fertilization results for a frozen epididymal Ban sperm lot with low fertility.

Invited review: reproductive physiology in commercial and premium pig breeds – history of 30-year-long cooperation

Abstract. Cooperation of the Hungarian Research Institute for Animal Breeding and Nutrition (ATK) with the German Leibniz Institute for Farm Animal Biology (FBN) goes back many decades. In 1988 the two departments of reproductive biology began a joint project concerning on ovulation investigation in Landrace pigs. This joint project laid the foundation for further joint projects and has existed for almost 30 years. Over the years, the main focus has always been on the events of the female reproductive tract in pigs, i.e., follicular growth, ovulation, transport of gametes in the oviduct, fertilization and early embryonic development. Nearly all studies were done under in vivo circumstances and using different clinical and endocrinological methods, enabling us to obtain more profound knowledge of the dynamics of reproductive processes. Even results considered to be basic scientific achievements were available for utilization in the daily practice of porcine reproductive management. Since the end of the 1990s, the common projects have been gradually shifted to the physiology of the Hungarian indigenous pig breed Mangalica. Research partners were convinced that modern utilization of indigenous pig breeds would open new doors for premium pork production. In addition to the Mangalica breed, this principal was broadened to non-European fatty-type native pig breeds as well and resulted in long-term, intercontinental scientific cooperation.

Differential expression of six genes in fat-type Hungarian Mangalica and other pigs

Abstract. In order to identify potential variances in gene expression of phenotypically different pig breeds, six fat-metabolism-related genes were analyzed in backfat and muscle tissues of fat-type Mangalica (MAN), Mangalica × Duroc (MD), and lean-type Hungarian Large White (HLW) and Pietrain × Duroc (PD) pigs by means of quantitative reverse transcription PCR (qRT-PCR). Higher (P < 0.05) adipocyte fatty-acid-binding protein (A-FABP) expression was observed in backfat and muscle tissues of purebred and crossbred MAN than in those of HLW and PD. In all breeds and crosses, adiponectin (ADIPOQ) was predominantly expressed in backfat at a similar level (P > 0.05), whereas muscle ADIPOQ expression was highest (P < 0.05) in MAN and MD. Levels of fatty acid synthase (FASN) mRNA were greatest in MAN, moderate in MD, and lowest in HLW and PD backfat and muscle. The fat mass and obesity-associated gene (FTO) was more abundant in MAN and MD backfat, whereas muscle expressions did not differ (P > 0.05) between breeds. Regarding leptin (LEP) expression, MAN produced the greatest levels in backfat, while HLW produced the lowest. In muscle, highest LEP was detected in MAN and MD. Between groups, perilipin 2 (PLIN2) was expressed similarly in backfat; however, PLIN2 was more abundant in muscle of MAN and MD than in that of HLW and PD. Differences in gene expression can contribute to the development of the characteristic fatty phenotype in MAN pigs. The identification of differentially expressed genes facilitates targeted sequencing and genotyping efforts for further studies.