Birth weight and its variation within a litter is an important economic trait in animal production, because low birth weight in animal correlates with lower survival rates, poor growth performance and sub-optimal carcass quality. However, there is a 2- to 3-fold variation in birth weight among littermates from normally fed sows in pigs. Although much attention has been paid to low birth weight piglets, it is still unknown why they have lower survival and growth rates, and sub-optimal carcass quality.
Recently, Researchers from Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) and University of Guelph, University of Manitoba & University of Ottawa), Canada and French National Institute for Agricultural Research, France found out that dysfunctions in intestinal absorptive capacity for amino acid may be one of the factors involved in the negatively influence of low birth weight on mortality and growth performance in piglets. They cloned Huanjiang mini-pig acidic amino acid transporter (EAAC1), and found out that the intestinal mRNA expression of the EAAC1 was lower in low birth weight piglets than high birth weight piglets from d 0 t0 d 14, as well as the protein expression from d 0 to d 7. The intestinal mRNA expression of B0AT1 and ASCT2 (neutral amino acid transporters) was also lower in low birth weight piglets, compared with in high birth weight piglets, from d 0 to d 14 and d 0 to d 7 respectively. B0AT1 and ASCT2 protein expression in the intestine of low birth weight piglets was also lower than in the intestine of high birth weight piglets from d 0 to d 7 and on d 7 respectively.
“About half of low birth weight piglets died during suckling, and more than seventy-？ve percent of post-natal deaths for low birth weight piglets occurred during the early suckling period.” said YANG Huansheng, a doctoral researcher at ISA. “The present study showed that low birth weight piglets had lower expression of neutral and acidic amino acid transporters in the early suckling period, which provides a new method to improve the situation by improving intestinal AA absorption”.
This research was supported by National Basic Research Program of China (2012CB124704), National Natural Science Foundation of China (No. 31110103909, 30901040, 30928018, and 31101729), National Scientific and Technology Support Project (2011BAD26B002-5) and Chinese Academy of Sciences Visiting Professorship for Senior International Scientists Grant No.2011T2S15.
The main findings of this study have published on Plos One http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050921#close and Molecular Biology Reports (http://link.springer.com/article/10.1007%2Fs11033-012-2409-y).