Natural alternatives to in-feed antibiotics in pig production: can immunomodulators play a role?

As a result of the European ban of in-feed growth-promoting antibiotics, new strategies are being developed to increase the resistance to disease in farm animals. In pig production, this is of particular importance during the weaning transition when piglets are subjected to major stressful events, making them highly sensitive to digestive disorders. At this time, the development of both innate and adaptive immunity at the mucosal surface is critical in preventing the potential harmful effects of intestinal pathogenic agents. Strategies aiming at stimulating natural host defences through the use of substances able to modulate immune functions have gained increasing interest in animal research, and different bioactive components a priori sharing those properties have been the subject of in vivo nutritional investigations in pig. Among these, yeast derivates (β-glucans and mannans) are able to interact with immune cells, particularly phagocytic cells. However, studies where they have been fed to pigs have shown inconsistent results, suggesting that their ability to target the sensitive immune cells through the oral route is questionable. The plant extracts, which would benefit from a positive image in the public opinion, have also been tested. However, due to a lack of data on the bioactive components of particular plants and the large diversity of species, it has proved difficult to prepare extracts of equivalent potency and thus, the literature on their influence on pig immunity remains inconclusive. In considering piglet immunity and health benefits, the most promising results to date have been obtained with spray-dried animal plasma, whose positive effects would be provided by specific antibodies and non-specific competition of some plasma components with bacteria for intestinal receptors. The major positive effect of spray-dried animal plasma is in reducing the infiltration of gut-associated lymphoid tissue by immune cells, which is likely to be the result of a decreased colonisation by potentially harmful bacteria. This review also highlights the limitations of some of the published in vivo studies on the immunomodulatory activity of certain feed additives. Among those, the lack of standardisation of extracts and the heterogeneity of piglet-rearing conditions (e.g. exposure to pathogens) are likely the most limiting.     

应用微卫星标记研究Dunkin Hartley豚鼠封闭群的遗传背景

目的检测我国现有Dunkin Hartley豚鼠封闭的遗传背景,分析评估其遗传多样性水平和遗传分离情况,为建立标准化的豚鼠封闭群监测方法提供基础资料。方法应用筛选获得的8个微卫星位点,从一个数量为1000的豚鼠封闭群中随机选择72个个体,通过PCR扩增和聚丙烯酰胺凝胶电泳的方法,进行等位基因检测。并根据检测结果分析评估了该豚鼠封闭群的遗传现状。结果共检测到28个等位基因,每个座位的等位基因数为2～5个,有效等位基因数为1.5191～3.4422,平均2.3093。平均期望杂合度为0.5294。各位点多态信息含量在0.3154～0.6545之间,平均值为0.4687。有5个位点显著偏离Hardy-Weinberg平衡。结论豚鼠封闭群的遗传多态性处于中等水平,遗传平衡检测结果提示种群的繁殖过程未能实现完全随机交配,近交现象一定程度上存在。本研究的结果将为豚鼠封闭群遗传监测方法和标准的建立提供基础。     

Expression patterns and association analysis of the porcine DHX58 gene

RIG-1 signalling is responsible for the detection of cytoplasmic viral RNA molecules. DEXH (Asp-Glu-X-His) box polypeptide 58 (encoded by DHX58) is a negative regulator of the RIG-1 signalling pathway. In human, the DHX58 gene can be upregulated and can inhibit the RIG-1 signalling pathway during viral infection. In this study, porcine DHX58 gene expression patterns were studied. According to our results, the porcine DHX58 gene was upregulated not only by the stimulation of Poly I:C but also by the stimulation of 1ipopolysaccharides (LPS). One polymorphism (g.4919G>C), detected in the ninth intron, was significantly associated with some blood parameters including the red cell distribution width of 1-day-old pigs and white blood cell counts, lymphocyte absolute counts, and platelet distribution width of 17-day-old pigs (P < 0.05). Moreover, the individuals with the genotype GG have a significantly higher mean white blood cell count than individuals with genotype CC or GC (P < 0.05). Our study indicates that DHX58 is an important gene that is associated with the immune response in swine.     

Fixed-time artificial insemination protocols on brazilian locally adapted breed gilts on ovulatory response and embryo production

The aim of this study was to use estrus synchronization protocols to favor fixed-time artificial insemination and consequently fixed-time embryo collection, and increase embryo production using eCG, in gits. In a cross over design, nine Piau breed gilts were subjected to 18 days of oral progesterone; P4 group did not receive any further; GnRH group received 25µg of GnRH 104 hours after the final application of P4; and eCG+GnRH group received 1000IU of eCG 24 hours after the final P4 in addition to GnRH for subsequent embryo collection, that was performed six days after first AI, by laparotomy. Artificial insemination was performed after 12 and 24 hours of estrus in P4 group, and 128 and 144 hours in GnRH and eCG+GnRH groups. The number of CL (8.6±3.9; 8.3±2.1; 26.7±15.0) and anovulatory follicles (4.3±3.7; 3.9±3.9; 17.2±9.5) was higher in the eCG+GnRH gilts (P<0.05). However, the use of 1000 IU of eCG reduced (P<0.05) the number of total structures (5.2±3.6; 5.1±3.1; 1.7±2.7), viable embryos (5.0±3.5; 4.8±3.3; 0.4±0.7), freezable embryos (3.6±3.4; 3.3±3.8; 0.1±0.3) and recovery rate (63.7±38.9; 58.6±24.7; 5.38±9.5). P4 and GnRH protocols were effective in the production and recovery of embryos. However, the use of 1000 IU of eCG, 24 hours after P4, was not effective in promoting the production of embryos, although the animals had superovulated.     

Characterization of Iberian pig genotypes using AFLP markers

The use of the AFLP (amplified fragment length polymorphism) technique for the characterization of highly inbred Iberian pig breed genotypes and the detection of strain-specific polymorphisms is demonstrated. Twelve different primer combinations were used on individual DNA samples from animals belonging to two black hairless Iberian pig strains, Guadyerbas and Coronado. These amplification reactions allowed the detection of more than 1700 amplification products of which 26 were identified as strain-specific markers, present in all individuals of one strain and absent in the other. Comparison of male and female amplification products within one strain also allowed the identification of 8 male-specific amplified bands. AFLP showed a great power of marker detection due to a high multiplex ratio and high reproducibility. Comparison of similarity and co-ancestry coefficient matrices also showed the usefulness of AFLP markers to estimate genetic relationships between individuals pigs.     

Heat stress upregulation of Toll-like receptors 2/4 and acute inflammatory cytokines in peripheral blood mononuclear cell (PBMC) of Bama miniature pigs: an in vivo and in vitro study

Global warming is a challenge to animal health, because of increased heat stress, with subsequent induction of immunosuppression and increased susceptibility to disease. Toll-like receptors (TLR) are pattern recognition receptors that act as sentinels of pathogen invasion and tissue damage. Ligation of TLRs results in a signaling cascade and production of inflammatory cytokines, which eradicate pathogens and maintain the health of the host. We hypothesized that the TLR signaling pathway plays a role in immunosuppression in heat-stressed pigs. We explored the changes in the expression of TLR2, TLR4 and the concentration of acute inflammatory cytokines, such as IL-2, IL-8, IL-12 and IFN-γ in Bama miniature pigs subjected to 21 consecutive days of heat stress, both in vitro and in vivo models. The results showed that heat stress induced the upregulation of cortisol in the plasma of pigs (P<0.05); TLR4 mRNA was elevated, but IL-2 was reduced in peripheral blood mononuclear cells (PBMC, P<0.05). The white blood cell count and the percentage of granulocytes (eosinophilic+basophilic) decreased significantly in heat-stressed pigs (P<0.05). In the in vitro model (PBMC heat shocked for 1 h followed by a 9 h recovery period), TLR2 and TLR4 mRNA expression also increased, as did the concentration of IL-12 in supernatants. However, IFN-γ was significantly reduced in PBMC culture supernatants (P<0.05). We concluded that a consecutive heat stress period elevated the expression of TLR2 and TLR4 in PBMC and increased the plasma levels of inflammatory cytokines. These data indicate that TLR activation and dysregulation of cytokine expression in response to prolonged heat stress may be associated with immunosuppression and increased susceptibility to antigenic challenge in Bama miniature pigs.     

Effect of dietary protein level on carcass traits and meat properties of Cinta Senese pigs

The aim of this study was to test the effect of various dietary protein contents (CP) on the carcass traits and the meat quality of Cinta Senese pigs. A total of 60 Cinta Senese pigs were equally distributed in four dietary groups that were balanced for sex (barrows and gilts) and live weight. The animals in the groups were fed one of four diets (80CP, 100CP, 130CP and 160CP) containing different CP contents (80, 100, 130 and 160 g/kg, respectively). The diets were administered to the pigs during the entire growing–fattening period in a controlled dose of 90 g/kg W^0.75, to a maximum of 2.5 kg/day per animal. The duration of the trial was ~250 days, ending when the animals reached the target slaughter weight of 145 kg. The 80CP diet produced fatter carcasses than did the other diets; no differences in carcass composition were found among the animals fed the other three diets (total lean cuts: 57.4%, 61.4%, 60.8% and 61.3% for 80CP, 100CP, 130CP and 160CP diet, respectively). The sample joint composition confirmed the highest fatness and the lowest meatiness of pigs fed 80CP. This same pattern was evident for the composition of the muscle (Longissimus lumborum) containing the largest amount of i.m. fat, and the lowest protein content in the 80CP group. Moreover, the 80CP diet resulted in the lightest and yellowest meat with the highest cooking loss. A principal component analysis of the physical and chemical traits of the meat revealed three first factors that explained 56% of the total variance. Among them, only the intersection of Factor1, which combined mainly lower pH at 24 h postmortem and higher drip loss, cooking loss, lightness and yellowness, with Factor2, which associated higher toughness, higher protein and lower fat content, graphically appeared to discriminate the 80CP diet from the other ones. In conclusion, a diet with 80 g/kg of CP content was inadequate for this local breed, while, in consideration of the cost of protein feed and the need to reduce N pollution, the 100CP diet would be an optimal compromise for the growth–fattening of Cinta Senese pigs.     

编辑MSTN半胱氨酸节基元促进两广小花猪肌肉生长

肌生长抑制素(myostatin,MSTN)是转化生长因子 β(transforming growth factor-β,TGF-β)家族成员之一,是一种肌肉生长抑制因子.解除MSTN的生长抑制功能是提高畜禽肌肉产量的一种有效途径.TGF-β 的半胱氨酸节结构基元(cystine knot motif)能够稳定MSTN...     

Relationship Among H-FABP Gene Polymorphism, Intramuscular Fat Content, and Adipocyte Lipid Droplet Content in Main Pig Breeds with Different Genotypes in Western China

H-FABP (Heart fatty acid-binding protein), a member of FABP family, plays an essential role in long-chain fatty acid uptake and metabolic homeostasis. Its role in pig intramuscular fat content remains poorly understood, especially in local pig breeds in western China. In this study, the genetic variations of 5′-upstream region and the second intron in porcine H-FABP gene were investigated by PCR-RFLP in 256 pigs including Duroc, Large White, Landrace, Neijiang, Rongchang, Bamei pig, Hanjiang Black, Hanzhong White, and the wild ones. The effect of H-FABP gene on the IMF content was analyzed by the least square method. Lipid droplet morphology and content in adipocytes cultured from pigs with different H-FABP genotypes, were studied by oil red O staining and a triglyceride assay kit. Results showed a Hinf I -RFLP in these eight pig breeds and wild pigs, among which Large white, Bamei pig, Hanjiang Black, Hanzhong White, and wild pigs presented with low polymorphism while the other breeds had intermediate polymorphism. There was no Hae III or Msp I -RFLPs in the four Chinese local pig breeds tested, but Duroc, Landrace, Large White, Hanzhong White and wild pig had polymorphism. Landrace, Large White and wild pigs had low levels of Hae III-and Msp I -RFLP, whereas others had intermediate polymorphism. H-FABP genotypes significantly affected the IMF content (P<0.05). The IMF content ordered by H-FABP genotypes were HH>Hh>hh, DD<Dd<dd, and AA<Aa<aa. The genetic effect values were 3.89, 3.42, 3.17, 2.27, 2.49, 2.91, 2.28, 2.70, and 2.95, respectively. Fat deposition in adipocytes was stronger in the HH, dd and aa genotypes than in others. The results suggest that porcine meat quality may be improved by increasing the frequency of genotype aa-dd-HH in pig breeds.