Impact of Intestinal Microbiota on Growth and Feed Efficiency in Pigs: A Review

Abstract

This review summarises the evidence for a link between the porcine intestinal microbiota and growth and feed efficiency (FE), and suggests microbiota-targeted strategies to improve productivity. However, there are challenges in identifying reliable microbial predictors of host phenotype; environmental factors impact the microbe–host interplay, sequential differences along the intestine result in segment-specific FE- and growth-associated taxa/functionality, and it is often difficult to distinguish cause and effect. However, bacterial taxa involved in nutrient processing and energy harvest, and those with anti-inflammatory effects, are consistently linked with improved productivity. In particular, evidence is emerging for an association of Treponema and methanogens such as Methanobrevibacter in the small and large intestines and Lactobacillus in the large intestine with a leaner phenotype and/or improved FE. Bacterial carbohydrate and/or lipid metabolism pathways are also generally enriched in the large intestine of leaner pigs and/or those with better growth/FE. Possible microbial signalling routes linked to superior growth and FE include increased intestinal propionate production and reduced inflammatory response. In summary, the bacterial taxa and/or metabolic pathways identified here could be used as biomarkers for FE/growth in pigs, the taxa exploited as probiotics or the taxa/functionality manipulated via dietary/breeding strategies in order to improve productivity in pigs.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

“…In humans, this window of time has been established as 100 days [ 56 ], a period during which dysbiosis and shifts in specific bacterial taxa have been related to an increased risk of asthma in future life [ 57 ]. While something similar is expected to occur in pigs [ 57 , 58 ], further research is needed to understand the impact of early life events on the piglet’s microbiome and its potential relevance for the pig industry [ 59 , 60 , 61 ]. Some authors have described how different exposure levels to stress or the use of antibiotics can determine changes in the gut microbial colonization of pigs eight days after birth with implications for immunity development [ 62 ].…”

Immunobiotic Feed Developed with Lactobacillus delbrueckii subsp. delbrueckii TUA4408L and the Soymilk By-Product Okara Improves Health and Growth Performance in Pigs

“…The improved growth performance and meat quality in pig production has been associated with good health status, particularly enhanced resistance to infections [ 2 , 3 , 19 ]. Hence, we studied the presence of symptoms associated with infectious diseases in the three experimental groups ( Table 2 ).…”

“…It was reported that the gut microbiota, through their metabolic activities and immunoregulatory functions, significantly influence the health of pigs and therefore, qualitative and/or quantitative changes in the intestinal microbial populations can significantly affect whole-body growth throughout the productive life cycle of these animals [ 3 , 38 ]. The most important modifications in the composition of the intestinal microbiota of pigs are produced during early life when piglets need to adapt to new diets and environments.…”

“…In this regard, probiotic microorganisms have been proposed as an alternative to avoid non-protective inflammation and to improve resistance against intestinal infections in piglets. These immunomodulatory probiotics or immunobiotics have been shown to positively influence the maturation of the immune system, the defenses against pathogens, and the control of detrimental inflammation [ 2 , 3 ]. Hence, the inclusion of immunobiotics in feed supplementation holds promise as a way to exert positive effects on weanling pigs [ 4 ].…”

Implications of Tributyrin on Gut Microbiota Shifts Related to Performances of Weaning Piglets

“…In addition to the above-described populations, other bacterial taxa resulted differentially present in the gut microbiota of tributyrin-fed piglets [ 46 ]. Most of the genera that are significantly increased in the tributyrin group have been described in previous works as enriched in high-feed efficiency pigs.…”