Area for nutrient absorption [28]. Moreover, the LBW piglets’ small intestine exhibited signs of immaturity, which may reduce the digestive and absorptive capacities [12]. To test whether the alterations of NAA contents in plasma, liver and skeletal muscle were related to the absorption process, the mRNA expression levels and protein abundances of two major NAA transporters, including Slc6a19 (B0AT1) and Slc1a5 (ASCT2), were examined. Consistent with the content alterations of NAA, the expression levels of both Slc6a19 (B0AT1) and Slc1a5 (ASCT2) were changed at early suckling period. These findings 22948146 suggested a relationship between 
intestine dysfunction and physiological change of other organs in the LBW piglets. Further work should be conducted to confirm this relationship. Other studies 
demonstrated that LBW in piglets correlates with decreased survival rates [2,5,6]. Two-thirds of piglets with BW lessthan 0.8 kg died during suckling, the mortality for piglets with BW of 0.81 to 1.0 kg is 34 and less than 10 for piglets above 1.6 kg BW [6]. More than Seventy-five percent of post-natal deaths for LBW piglets occurred within the first week after birth. According to the results of the present study, LBW piglets had alterations in contents of some of NAA in plasma, liver and skeletal muscle, and lower jejunal expression of Slc6a19 (B0AT1) and Slc1a5 (ASCT2) during the first week after birth, which suggested that the intestinal dysfunction may be one of the reason for the high mortality of LBW piglets. Other studies showed that the differences in the intestinal shape and enzymatic functions between IUGR and order SC 1 normal BW piglets lessen with the increase of age [12], the alterations in NAA contents and their transporters between HBW and LBW piglets also faded out with increasing age. Moreover, the difference in mortality of HBW and LBW piglets was also disappeared as animals became older [6]. Pigs with LBW required a longer growing time to reach the same market weight than their HBW Docosahexaenoyl ethanolamide biological activity littermates [29]. A number of possible mechanisms underlying these differences are under discussion. Long-term modifications in the growth-regulating hormonal 23727046 axes could be the reason for lower growth performances of LBW neonates. Indeed, low BW piglets had a lower circulating concentration of IGF-1 compared with their HBW littermates [30]. Another hypothesis is that the LBW piglets consumed less milk per suckling and compete less effectively for food than their HBW littermates [31]. It is also possible that LBW suffer long-term negative effects on the efficiency of feed utilization, since the intestine of LBW piglets not only exhibited morphological changes but also with physiological and functional alterations. The results of the present study demonstrated inhibition of expression of NAA transporters in the jejunum of LBW piglets during the early suckling period, which is in agreement with the hypothesis the lower growth performances of LBW piglets may be due to theirNeutral Amino Acids in Mini-Pigletsinefficiency in using dietary nutrient. The low intestinal capacity for AA transport in LBW piglets’ intestine would further limit the development and growth of piglets with an already lower BW. Although the differences in plasma, liver and skeletal muscle NAA contents, and jejunal expression of transporters for NAA between LBW and HBW piglets was gradually disappeared during suckling, the difference in growth performance between LBW and HBW pigs was also disappear.Area for nutrient absorption [28]. Moreover, the LBW piglets’ small intestine exhibited signs of immaturity, which may reduce the digestive and absorptive capacities [12]. To test whether the alterations of NAA contents in plasma, liver and skeletal muscle were related to the absorption process, the mRNA expression levels and protein abundances of two major NAA transporters, including Slc6a19 (B0AT1) and Slc1a5 (ASCT2), were examined. Consistent with the content alterations of NAA, the expression levels of both Slc6a19 (B0AT1) and Slc1a5 (ASCT2) were changed at early suckling period. These findings 22948146 suggested a relationship between intestine dysfunction and physiological change of other organs in the LBW piglets. Further work should be conducted to confirm this relationship. Other studies demonstrated that LBW in piglets correlates with decreased survival rates [2,5,6]. Two-thirds of piglets with BW lessthan 0.8 kg died during suckling, the mortality for piglets with BW of 0.81 to 1.0 kg is 34 and less than 10 for piglets above 1.6 kg BW [6]. More than Seventy-five percent of post-natal deaths for LBW piglets occurred within the first week after birth. According to the results of the present study, LBW piglets had alterations in contents of some of NAA in plasma, liver and skeletal muscle, and lower jejunal expression of Slc6a19 (B0AT1) and Slc1a5 (ASCT2) during the first week after birth, which suggested that the intestinal dysfunction may be one of the reason for the high mortality of LBW piglets. Other studies showed that the differences in the intestinal shape and enzymatic functions between IUGR and normal BW piglets lessen with the increase of age [12], the alterations in NAA contents and their transporters between HBW and LBW piglets also faded out with increasing age. Moreover, the difference in mortality of HBW and LBW piglets was also disappeared as animals became older [6]. Pigs with LBW required a longer growing time to reach the same market weight than their HBW littermates [29]. A number of possible mechanisms underlying these differences are under discussion. Long-term modifications in the growth-regulating hormonal 23727046 axes could be the reason for lower growth performances of LBW neonates. Indeed, low BW piglets had a lower circulating concentration of IGF-1 compared with their HBW littermates [30]. Another hypothesis is that the LBW piglets consumed less milk per suckling and compete less effectively for food than their HBW littermates [31]. It is also possible that LBW suffer long-term negative effects on the efficiency of feed utilization, since the intestine of LBW piglets not only exhibited morphological changes but also with physiological and functional alterations. The results of the present study demonstrated inhibition of expression of NAA transporters in the jejunum of LBW piglets during the early suckling period, which is in agreement with the hypothesis the lower growth performances of LBW piglets may be due to theirNeutral Amino Acids in Mini-Pigletsinefficiency in using dietary nutrient. The low intestinal capacity for AA transport in LBW piglets’ intestine would further limit the development and growth of piglets with an already lower BW. Although the differences in plasma, liver and skeletal muscle NAA contents, and jejunal expression of transporters for NAA between LBW and HBW piglets was gradually disappeared during suckling, the difference in growth performance between LBW and HBW pigs was also disappear.