**4. Microbiota involvement during pregnancy, parturition and lactation**

The composition of gut microbiota constantly shifts over time and it is not constant. In sows, both diversity and abundance of certain microbial population increase with progression of the pregnancy until weaning [64]. Diversified gut microbiota can provide different metabolic capacities and functionality in sows, ensuring the sufficient supply of nutrients for fetal growth and development [64]. In a recent study carried out by Hasan et al. [65], at farrowing, from a phyla level perspective, most gut bacteria were classified in Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Candidatus. The Firmicutes represent the most abundant proportion of the total population, followed by Bacteroides. These two phyla accounted for approximately 98% of all bacteria present. These results are in line with the one published by Kim et al. [66], reporting Firmicutes and Bacteroides being 90% of total bacteria present in late pregnancy in the sow gut. However, the findings of the study by Ji et al. [64], reported that Bacteroides increased linearly with the progression of the pregnancy and represented the most dominant (45%) in late pregnancy. Jost et al. [67] reported that Firmicutes exhibited no detectable changes over perinatal period. There are some evidences that gestational body weight gain or increase in the back-fat thickness in the sows, may be associated with an increase in the abundance of Firmicutes or an increase in the Firmicutes to Bacteroides ratio [64, 68]. In terms of phyla, the abundance of Tenericutes, Fibrobacteres, and Cyanobacteria have been shown to increase with the progression of the pregnancy [64]. These phyla have some beneficial effects, for example, Tenericutes increase intestinal cells' integrity and Fibrobacteres are characterized by having the potential to metabolize non-soluble polysaccharides, such as cellulose, hemicellulose or pectin [64]. During late gestation Romboutsia was the dominant genus in sows which is from the phylum Firmicutes, followed by Clostridium sensu stricto, Lactobacillus, Oscillibacter, Intestinimonas, Sporobacter, Christensenella, Barnesiella, Flavonifractor, Terrisporobacter, Acidaminobacter, Lachnospiracea incertae sedis, and Turicibacter, other genera being much less 1% [65].

The changes in the diet can differentiate the composition of the microbiome, and in its potential functionality. Recent studies demonstrate the importance of dietary microbial modulation. Dietary supplementation of hydrolysed yeast [65], resin acid enriched composition [69], probiotics [70] and prebiotics [71, 72] in sow's late gestation diet, significantly changes microbial populations. Different levels and types of protein and fiber in the diet are also modulating the gut microbial population both in gestating sows and in weaning piglets. Fiber has various

**65**

pressed [65].

*Troubled Process of Parturition of the Domestic Pig DOI: http://dx.doi.org/10.5772/intechopen.94547*

physicochemical properties, and its supplementation during pregnancy effectively enhances the stability of the gut microbiota population in sow [71, 72]. The most important changes in the gut microbiota composition include a reduction in

Proteobacteria and an increase in Ruminococcaceae, Oscillospira, and Eubacterium. Additionally, the genus Eubacterium increases, after dietary soluble fiber supplementation during pregnancy, promoting propionate release, being one of the possible reasons by which dietary fiber increases insulin sensitivity and decrease the general inflammation in sows around farrowing [73]. Those microbiota capable to ferment indigestible carbohydrates, produce short chain fatty acids (SCFA) that can be an important energy source for the sow. Butyrate, in particular, is a gut health-promoting compound that acts as the main energy source for colonocytes and exerts anti-inflammatory properties [74]. The increased production of SCFAs promotes intestinal energy availability, which may contribute to the high energetic demands of hyper-prolific sows for the longer duration of farrowing process; therefore promoting the presence of fiber degrading gut microbiota seems to be favorable for gestating sows. The reduction of pathogenic bacteria in response to dietary supplementation is associated with an increase of beneficial microbiota, which in turn may modify the substrate availability and the physiological conditions of the gastrointestinal tract (e.g. fermentation products, luminal pH and bile acid concentration) [75]. Dietary supplementation of yeast hydrolysate in the pregnancy influenced beneficial and fermentative bacteria (Roseburia, Paraprevotella,

Eubacterium), while, some opportunistic pathogens like Desulfovibrio, Escherichia/Shigella and Helicobacter, of the phylum Proteobacteria, were sup-

**5. Robustness needed, resilience favored**

sensitive to heat in comparison to less productive breeds [81].

Proteobacteria are usually a minority presence within a normal gut microbial community [76]. However, a dysbiotic expansion of facultative anaerobic Proteobacteria are connected with gut inflammation, including irritable bowel syndrome, inflammatory bowel disease in humans [77], and with increased inflammatory responses of women in late pregnancy [78]. Recent studies have proposed that an expansion of Proteobacteria in the gut microbiota community is a potential diagnostic criterion for dysbiosis in gut microbiota and epithelial dysfunction [79, 80]. For instance, Hasan et al. [65] found that some positive sow's productive and physiological performances (high colostrum yield, high colostrum proteins content, high colostrum IgG content, normal blood progesterone level and normal farrowing duration) were positively correlated to the gut bacterial families *Lactobacillaceae, Ruminococcaceae and Prevotellaceae,* the last two being bacteria able to utilize different plant cell wall polysaccharides. On the contrary, unfavorable productive and physiological performances of the sow (low colostrum yield, low colostrum proteins content, low colostrum IgG content, high level of blood progesterone and long farrowing duration) clustered and were positively correlated with the gut bacterial families *Erysipelotrichaceae, Clostridiaceae, Streptococcaceae, Enterobacteriaceae, Desulfovibrionaceae and Bacteroidaceae,* many of these being known pig pathogens bacteria or part of the dysbiotic phylum Proteobacteria*.*

The climate change requires a brave vision regarding breeding goals in the pig in the future. Buildings housing pigs will need to be energy saving and reducing CO2 emissions in the future. On the other hand, hotter climate will need pigs to be robust and more resilient under heat with less susceptible to becoming stressed under those conditions. Hyper-prolific sows, however, may actually be quite

### *Troubled Process of Parturition of the Domestic Pig DOI: http://dx.doi.org/10.5772/intechopen.94547*

*Animal Reproduction in Veterinary Medicine*

suckling [2].

more plasma IgG (21.5 vs. 17.1%), probably because of their greater development of intestinal villi [60]. Klobasa et al. [61] found that birth order had an influence on the amount of immunoglobulin absorbed in a population of 600 piglets. The latest piglets born in the litters had the lower IgG level in their plasma, due to the fast decline in colostrum immunoglobulins level from the start of parturition. Correspondingly, another study reported a 4% decrease of plasma IgG concentration in piglets of smaller birth weight, when compared to their bigger siblings [62]. Manjarin et al. [63] indicated the farrowing-to-suckling interval to be fundamental in the acquisition of adequate IgG by piglets. A 4 h delayed intake of colostrum, after the start of parturition, significantly reduced the amount of piglets' plasma proteins 24 hours up to 12 days. It is therefore extremely important to consider also the time of birth of piglets in relation to the start of farrowing, when planning successful strategies to boost colostrum intake in large litters, like for instance split

**4. Microbiota involvement during pregnancy, parturition and lactation**

The composition of gut microbiota constantly shifts over time and it is not constant. In sows, both diversity and abundance of certain microbial population increase with progression of the pregnancy until weaning [64]. Diversified gut microbiota can provide different metabolic capacities and functionality in sows, ensuring the sufficient supply of nutrients for fetal growth and development [64]. In a recent study carried out by Hasan et al. [65], at farrowing, from a phyla level perspective, most gut bacteria were classified in Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Candidatus. The Firmicutes represent the most abundant proportion of the total population, followed by Bacteroides. These two phyla accounted for approximately 98% of all bacteria present. These results are in line with the one published by Kim et al. [66], reporting Firmicutes and Bacteroides being 90% of total bacteria present in late pregnancy in the sow gut. However, the findings of the study by Ji et al. [64], reported that Bacteroides increased linearly with the progression of the pregnancy and represented the most dominant (45%) in late pregnancy. Jost et al. [67] reported that Firmicutes exhibited no detectable changes over perinatal period. There are some evidences that gestational body weight gain or increase in the back-fat thickness in the sows, may be associated with an increase in the abundance of Firmicutes or an increase in the Firmicutes to Bacteroides ratio [64, 68]. In terms of phyla, the abundance of Tenericutes, Fibrobacteres, and Cyanobacteria have been shown to increase with the progression of the pregnancy [64]. These phyla have some beneficial effects, for example, Tenericutes increase intestinal cells' integrity and Fibrobacteres are characterized by having the potential to metabolize non-soluble polysaccharides, such as cellulose, hemicellulose or pectin [64]. During late gestation Romboutsia was the dominant genus in sows which is from the phylum Firmicutes, followed by Clostridium sensu stricto, Lactobacillus, Oscillibacter, Intestinimonas, Sporobacter, Christensenella, Barnesiella, Flavonifractor, Terrisporobacter, Acidaminobacter, Lachnospiracea

incertae sedis, and Turicibacter, other genera being much less 1% [65].

The changes in the diet can differentiate the composition of the microbiome, and in its potential functionality. Recent studies demonstrate the importance of dietary microbial modulation. Dietary supplementation of hydrolysed yeast [65], resin acid enriched composition [69], probiotics [70] and prebiotics [71, 72] in sow's late gestation diet, significantly changes microbial populations. Different levels and types of protein and fiber in the diet are also modulating the gut microbial population both in gestating sows and in weaning piglets. Fiber has various

**64**

physicochemical properties, and its supplementation during pregnancy effectively enhances the stability of the gut microbiota population in sow [71, 72]. The most important changes in the gut microbiota composition include a reduction in Proteobacteria and an increase in Ruminococcaceae, Oscillospira, and Eubacterium. Additionally, the genus Eubacterium increases, after dietary soluble fiber supplementation during pregnancy, promoting propionate release, being one of the possible reasons by which dietary fiber increases insulin sensitivity and decrease the general inflammation in sows around farrowing [73]. Those microbiota capable to ferment indigestible carbohydrates, produce short chain fatty acids (SCFA) that can be an important energy source for the sow. Butyrate, in particular, is a gut health-promoting compound that acts as the main energy source for colonocytes and exerts anti-inflammatory properties [74]. The increased production of SCFAs promotes intestinal energy availability, which may contribute to the high energetic demands of hyper-prolific sows for the longer duration of farrowing process; therefore promoting the presence of fiber degrading gut microbiota seems to be favorable for gestating sows. The reduction of pathogenic bacteria in response to dietary supplementation is associated with an increase of beneficial microbiota, which in turn may modify the substrate availability and the physiological conditions of the gastrointestinal tract (e.g. fermentation products, luminal pH and bile acid concentration) [75]. Dietary supplementation of yeast hydrolysate in the pregnancy influenced beneficial and fermentative bacteria (Roseburia, Paraprevotella, Eubacterium), while, some opportunistic pathogens like Desulfovibrio, Escherichia/Shigella and Helicobacter, of the phylum Proteobacteria, were suppressed [65].

Proteobacteria are usually a minority presence within a normal gut microbial community [76]. However, a dysbiotic expansion of facultative anaerobic Proteobacteria are connected with gut inflammation, including irritable bowel syndrome, inflammatory bowel disease in humans [77], and with increased inflammatory responses of women in late pregnancy [78]. Recent studies have proposed that an expansion of Proteobacteria in the gut microbiota community is a potential diagnostic criterion for dysbiosis in gut microbiota and epithelial dysfunction [79, 80]. For instance, Hasan et al. [65] found that some positive sow's productive and physiological performances (high colostrum yield, high colostrum proteins content, high colostrum IgG content, normal blood progesterone level and normal farrowing duration) were positively correlated to the gut bacterial families *Lactobacillaceae, Ruminococcaceae and Prevotellaceae,* the last two being bacteria able to utilize different plant cell wall polysaccharides. On the contrary, unfavorable productive and physiological performances of the sow (low colostrum yield, low colostrum proteins content, low colostrum IgG content, high level of blood progesterone and long farrowing duration) clustered and were positively correlated with the gut bacterial families *Erysipelotrichaceae, Clostridiaceae, Streptococcaceae, Enterobacteriaceae, Desulfovibrionaceae and Bacteroidaceae,* many of these being known pig pathogens bacteria or part of the dysbiotic phylum Proteobacteria*.*
