Increases in circulating amino acids with in-feed antibiotics correlated with gene expression of intestinal amino acid transporters in piglets

Abstract

In-feed antibiotics have been commonly used to promote the growth performance of piglets. The antibiotics can increase protein utilization, but the underlying mechanism is largely unknown. The present study investigated the effects of in-feed antibiotics on intestinal AA transporters and receptors to test the hypothesis that the alteration of circulating AA profiles may be concomitant with the change of intestinal AA transporters and receptors. Sixteen litters of piglets at day 7 started to receive creep feed with (Antibiotic) or without (Control) antibiotic. Piglets were weaned at day 23 after birth, and fed the same diets until day 42. In-feed antibiotics did not affect the BW of 23-day-old (P = 0.248), or 42-day-old piglets (P = 0.089), but increased the weight gain to feed ratio from day 23 to 42 (P = 0.020). At day 42 after birth, antibiotic treatment increased the concentrations of most AAs in serum (P < 0.05), and decreased the concentrations of most AAs in jejunal and ileal digesta. Antibiotics upregulated (P < 0.05) the mRNA expression levels for jejunal AAs transporters (CAT1, EAAC1, ASCT2, yLAT1), peptide transporters (PepT1), and Na-K-ATPase (ATP1A1), and ileal AA transporters (ASCT2, yLAT1, bAT, and BAT1), and ATP1A1. The antibiotics also upregulated the mRNA expression of jejunal AAs receptors T1R3 and CaSR, and ileal T1R3. Protein expression levels for jejunal AA transporters (EAAC1, bAT, and ASCT2) and PepT1 were also upregulated. Correlation analysis revealed that the alterations of AA profiles in serum after the in-feed antibiotics were correlated with the upregulations of mRNA expression levels for key AA transporters and receptors in the small intestine. In conclusion, the in-feed antibiotics increased serum level of most AAs and decreased most AAs in the small intestine. These changes correlated with the upregulations of mRNA expression levels for key AA transporters and receptors in the small intestine. The findings provide further insights into the mechanism of in-feed antibiotics, which may provide new framework for designing alternatives to antibiotics in animal feed in the future.

Increasing carbohydrate availability in the hindgut promotes hypothalamic neurotransmitter synthesis: aromatic amino acids linking the microbiota–brain axis

“…; Yu et al . ), was up‐regulated by 6.25‐fold in the colon as revealed by qRT‐PCR (Fig. a, p < 0.05), while the gene expression of LAT1 remained unchanged (Fig.…”

“…The western blotting of signaling factors in AAA‐treated neuronal cells was performed according to a method previously described (Yu et al . ). In brief, mouse neuronal cells treated with single AAA for 24 h were lysed using lysis buffer (Sigma‐Aldrich) according to the manufacturer's instructions.…”

Antibiotics‐induced modulation of large intestinal microbiota altered aromatic amino acid profile and expression of neurotransmitters in the hypothalamus of piglets

“…The small intestine is the major site for amino acid absorption and AAAs have been reported to be transported via neutral amino acid transporters, such as large amino acid transporter (Yu et al . ). In the present study, while the concentrations of these AAAs remained unaltered in the small intestine, they were decreased in the large intestine.…”

Caecal infusion of the short‐chain fatty acid propionate affects the microbiota and expression of inflammatory cytokines in the colon in a fistula pig model

“…The primers for genes related inflammation are listed in Table S2. Amplification was performed by the ABI 7300 Real‐Time qPCR system (Applied Biosystems, Foster, CA, USA) with fluorescence detection of SYBR green dye, the reaction conditions were previously described by Yu and colleagues (). The relative expression of genes was calculated using the method.…”