E. coli infection modulates the pharmacokinetics of oral enrofloxacin by targeting P-glycoprotein in small intestine and CYP450 3A in liver and kidney of broilers.

P-glycoprotein (P-gp) expression determines the absorption, distribution, metabolism and excretion of many drugs in the body. Also, up-regulation of P-gp acts as a defense mechanism against acute inflammation. This study examined expression levels of abcb1 mRNA and localization of P-gp protein in the liver, kidney, duodenum, jejunum and ileum in healthy and E. coli infected broilers by real time RT-PCR and immunohistochemistry. Meanwhile, pharmacokinetics of orally administered enrofloxacin was also investigated in healthy and infected broilers by HPLC. The results indicated that E. coli infection up-regulated expression of abcb1 mRNA levels significantly in the kidney, jejunum and ileum (P<0.05), but not significantly in the liver and duodenum (P>0.05). However, the expression level of CYP 3A37 mRNA were observed significantly decreased only in liver and kidney of E. coli infected broilers (P<0.05) compared with healthy birds. Furthermore, the infection reduced absorption of orally administered enrofloxacin, significantly decreased Cmax (0.34 vs 0.98 µg mL(-1), P = 0.000) and AUC0-12h (4.37 vs 8.88 µg mL(-1) h, P = 0.042) of enrofloxacin, but increased Tmax (8.32 vs 3.28 h, P = 0.040), T1/2a(2.66 vs 1.64 h(-1), P = 0.050) and V/F (26.7 vs 5.2 L, P = 0.040). Treatment with verapamil, an inhibitor of P-gp, significantly improved the absorption of enrofloxacin in both healthy and infected broilers. The results suggest that the E. coli infection induces intestine P-gp expression, altering the absorption of orally administered enrofloxacin in broilers

Effect of Lipase and Lysolecithin Supplementation with Low Energy Diet on Growth Performance, Biochemical Attributes and Fatty Acid Profile of Breast Muscle of Broiler Chickens

This study aimed to investigate the effect of dietary lysolecithin (LYSO) and lipase supplementation on productive performance, nutrient retention, and meat quality of broiler chicken fed a low energy diet. For this purpose, a total of 360 chicks were randomly alienated into six treatments, having six replicates (no = 10) birds each replicate. The dietary treatments were followed as control (CON fed as normal energy diet), LE (CON—100 kcal/kg from BD. basal diet), LIP 0.04 (LE + 0.04% lipase), LYSO 0.04 (LE + 0.04% lysolecithin), LIP + LYSO 0.04 (LE + 0.04% lipase and lysolecithin), and LIP + LYSO 0.08 (LE. + 0.08% lipase and lysolecithin). The birds fed with LIP + LYSO 0.04 exhibited higher weight gain than LYSO 0.08 and CON (p p > 0.05). Effects of experimental diets on dry matter (DM), crude protein (CP), and fat digestibility were also non-significant (p > 0.05). Similarly, the blood biochemical profile (total cholesterol, triglycerides, LDL, HDL) of the broiler showed no significant difference (p > 0.05) by dietary treatments. Similarly, liver enzymes, AST and A.L.T., were also not statistically significant (p > 0.05) among all dietary treatments. Similarly, supplementation of LIP and LYSO had a non-significant (p > 0.05) effect on breast meat fatty acids composition. Conclusively, adding LIP + LYSO 0.08 to a low energy diet could demonstrate better growth performance and reduce the negative impact of a low-energy diet

Plasma concentration-time profiles of orally administered enrofloxacin (10 mg/kg b.w.) in the broilers of 4 and 8 week old.

<p>Data represent mean ± S.E. (n=10).</p

Expression of P-gp mRNA in broilers at different ages.

<p>(A) Expression levels of P-gp mRNA in liver, jejunum, ileum and duodenum in broilers at indicated ages, as detected by real time RT PCR. (B) Relative comparison of expression levels of P-gp mRNA in jejunum, ileum and duodenum in 4 week-old broilers, as detected by real time RT PCR. β-actin was used as a reference gene for normalization (n=5). ** difference between ages of tissues (<i>P</i><0.01).</p

Expression levels of <i>abcb1</i> mRNA in broilers by real time RT PCR (n = 5).

<p>A: Differences of <i>abcb1</i> mRNA level in liver, jejunum, ileum and duodenum between healthy and <i>E. coli</i> infected broilers; B: Comparison of <i>abcb1</i> mRNA level in different tissues of infected broilers. β-actin was used as a reference gene for normalization. All data were presented as mean ± S.E.M. and analyzed by one-way ANOVA using SPSS 16.0 for Windows followed by a least-significant difference (LSD) test for individual comparisons. * <i>P</i><0.05, ** <i>P</i><0.01.</p

Mean plasma enrofloxacin concentrations in broilers after enrofloxacin administration.

<p>A: enrofloxacin alone by single oral administration (10 mg/kg) to healthy (n = 10) and infected (n = 10) broilers; B: enrofloxacin after a single oral administration of 10 mg/kg alone (n = 10) and co-administration of verapamil (15 mg/kg, n = 10) to <i>E. coli</i> infected broilers C: enrofloxacin after a single oral administration of 10 mg/kg alone (n = 10) and co-administration of verapamil (15 mg/kg, n = 10) to healthy broilers. Each point represents the mean ±S.E.M. of 10 broilers.</p

Plasma concentration-time profiles of orally administered enrofloxacin (10 mg/kg b.w.) in the presence and absence of verapamil (15 mg/kg b.w.) in the broilers of 4 week old (A) and 8 week old (B).

<p>Data represent mean ± S.E. (n=10).</p

Parameters of oral enrofloxacin in healthy and infected broilers (mean ± S.E.M., n = 10).

*<p><i>P</i><0.05, ** <i>P</i><0.01 significant difference vs. healthy broliers. <i>K_e:</i>,elimination rate constant; <i>K_a</i>, absorption rate constant; <i>t</i>_1/2a, the absorption half-life; <i>t</i>_1/2e, the elimination half-life; T_max, the time to reach peak concentration; C_max, the peak concentration; AUC_0-12h, the area under the plasma concentration-time curve from zero to 12h; V/F, volume of distribution/F, where F is the faction of dose absorbed; Cl/F, Clearance/F, where F is the faction of dose absorbed.</p

Semi-quantification of P-gp in both healthy and <i>E. coli</i> infected broilers.

<p>The intensity of specific P-gp staining was evaluated by measuring the IOD, area of positive staining and scores of its expression respectively. Digital images of five sections from each broiler of the surface epithelium area were evaluated. Each section was divided into five sub-areas, and the IOD and positive area of the staining was analyzed using the Image-Pro Plus 4.1. software and scores were analyzed from 0 to 4 to estimate the positive staining in different areas under study.*<i>P</i><0.05, *<i>*P</i><0.01.</p

Immunohistochemical staining of P-glycoprotein in different tissues of healthy and <i>E. coli</i> infected broilers.

<p>Mouse monoclonal anti-P-gp antibody (C219) was used to detect P-gp. These figures are representatives of typical samples from 5 broilers in each group. The arrow showed the positive staining of P-gp. Magnifications are indicated by bar.</p