Dietary tributyrin intervention ameliorates the development of internal organs in IUGR piglets

1． The adverse effect of IUGR

Intrauterine growth retardation (IUGR) usually refers to the retarded growth and development of the fetus or its inner organs during the perinatal period due to various factors, which not only reduces the birth quality and survival rate of piglets, but also negatively affected their growth and development after birth (Longo et al., 2014). The incidence of IUGR in pigs is as high as 20%, which brings huge losses to the pig production (Wu et al., 2004).

2．Effect of dietary tributyrin intervention on IUGR piglets

Li et al. (2015) and He et al. (2016) have conducted several studies regarding the dietary tributyrin intervention on the IUGR piglets. Three treatments were included in the studies, including the normal group (NBW group, normal piglets + basic artificial milk), the IUGR group (IUGR piglets + basic artificial milk), and the tributyrin-fed group (IT group, IUGR piglets + basic artificial milk + 0.1% tributyrin). The results are as follows:

2.1  Dietary tributyrin intervention improved the pancreas and liver development in IUGR piglets

Their results showed that the weights of pancreas and liver in the IUGR pigs were lower than that in the normal ones (P < 0.05), while dietary tributyrin intervention on the IUGR pigs increased the weights of these organs by 31.03% and 52.32% when compared with those in the IUGR pigs consuming normal feed, respectively. The central vein and portal area of liver in the IUGR pigs were seriously congested, while no such pathologic changes were observed in response to dietary tributyrin intervention.

2.2  Dietary tributyrin intervention improved the intestinal villi morphology in the IUGR pigs

2.3  Dietary tributyrin intervention ameliorated the liver congestion in IUGR piglets

2.4 Dietary tributyrin intervention improved the pancreatic enzyme activity in IUGR piglets

The trypsin, pancreatic lipase and amylase in the IUGR piglets were lower than those in the normal pigs (P < 0.05), while these in the IUGR pigs with dietary tributyrin intervention were increased by 36.92%, 52.30% and 141.37%, respectively.

2.5  Dietary tributyrin intervention reduced the inflammation response in the liver of IUGR piglets

The liver contents of tumor necrosis factor (TNF-) and interleukin 4 (il-4) were significantly higher in the IUGR piglets than those in the normal ones, while these in the IUGR pigs with dietary tributyrin intervention were reduced by 35.20% and 20.52%, respectively.

2.6  Dietary tributyrin intervention improved the antioxidant capacity of IUGR piglets

The SOD and GSH are important antioxidants and free radical scavenger, while GSH-Px is an important organic peroxide decomposition enzyme, and MDA is the end product of lipid peroxidation. Dietary tributyrin intervention increased the activities of SOD, GSH and GSH-Px, and reduced the MDA content in IUGR piglets, respectively. 

2.7  Dietary tributyrin intervention ameliorated the mitochondria function in liver of IUGR piglets

Mitochondria is the place where nutrients are oxidized and metabolized to produce ATP, which  is the main place where oxygen free radicals are produced as well. Mitochondria content is extremely high in the liver tissues. SDH is the only enzyme embedded in the inner membrane of mitochondrial in the tricarboxylic acid cycle. MDH is an important oxidoretase, and Mn-SOD mainly exists in the mitochondrial matrix. As an antioxidant, Mn-SOD plays an important role for diseases prevention. The results showed that dietary tributyrin intervention increased the activity of SDH, MDH and Mn-SOD in liver of IUGR piglets (P < 0.05).

2.8  Summary

(1) Dietary tributyrin intervention increased the weight of pancreas and liver of IUGR piglets;

(2) Dietary tributyrin intervention improved the intestinal morphology of IUGR piglets;

(3) Dietary tributyrin intervention relieved liver congestion in IUGR piglets;

(4) Dietary tributyrin intervention enhanced the activity of various pancreatic enzyme in IUGR piglets;

(5) Dietary tributyrin intervention reduced inflammation responses in IUGR piglets;

(6) Dietary tributyrin intervention improved the antioxidant capacity of IUGR piglets;

(7) Dietary tributyrin intervention improved the mitochondrial function in the liver of IUGR piglet.