2 results
Intestinal permeability induced by lipopolysaccharide and measured by lactulose, rhamnose and mannitol sugars in chickens
- S. Gilani, G. S. Howarth, S. M. Kitessa, C. D. Tran, R. E. A. Forder, R. J. Hughes
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Increased intestinal permeability (IP) can lead to compromised health. Limited in vivo IP research has been conducted in chickens. The objectives of the current study were to develop a model of increased IP utilizing lipopolysaccharide (LPS Escherichia coli O55:B5) and to evaluate IP changes using the lactulose, mannitol and rhamnose (LMR) sugar permeability test. In addition, fluorescein isothiocyanate dextran (FITC-d), d-lactate, zonula occludens (ZO-1) and diamine oxidase (DAO) permeability tests were employed. Male Ross chickens were reared until day 14 on the floor in an animal care facility and then transferred to individual cages in three separate experiments. In each of experiments 1 and 2, 36 chicks were randomly allocated to receive either saline (control) or LPS (n=18/group). Lactulose, mannitol and rhamnose sugar concentration in blood was measured at 0, 30, 60, 90, 120 and 180 min in experiment 1, at 60, 90 and 120 min in experiment 2 and at 90 min in experiment 3 (n=16/group). Lipopolysaccharide was injected intraperitoneally at doses of 0.5, 1 and 1 mg/kg BW in experiments 1, 2 and 3, respectively, on days 16, 18 and 20, whereas control received sterile saline. On day 21, only birds in experiments 1 and 2 were fasted for 19.5 h. Chicks were orally gavaged with the LMR sugars (0.25 gL, 0.05 gM, 0.05 gR/bird) followed by blood collection (from the brachial vein) as per time point for each experiment. Only in experiment 3, were birds given an additional oral gavage of FITC-d (2.2 mg/ml per bird) 60 min after the first gavage. Plasma d-lactate, ZO-1 and DAO concentrations were also determined by ELISA in experiment 3 (n=10). Administration of LPS did not affect IP as measured by the LMR sugar test compared with control. This was also confirmed by FITC-d and DAO levels in experiment 3 (P>0.05). The plasma levels of d-lactate were decreased (P<0.05). Plasma levels of ZO-1 were increased in the third experiment only and did not change in the first two experiments. Lipopolysaccharide at doses of 0.5 and 1 mg/kg did not increase IP in this model system. In conclusion, the LMR sugar can be detected in blood 90 min after the oral gavage. Further studies are needed for the applicability of LMR sugars tests.
The effect of continuous or rotational stocking on the intake and live-weight gain of cattle co-grazing with sheep on temperate pastures
- S. M. Kitessa, A. M. Nicol
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- Journal:
- Animal Science / Volume 72 / Issue 1 / February 2001
- Published online by Cambridge University Press:
- 18 August 2016, pp. 199-208
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- February 2001
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Two experiments were conducted to determine if type of stocking system influenced the intake and live-weight gain (LWG) of cattle co-grazed with sheep on sown ryegrass/white clover pasture.
In experiment 1 (134 days), yearling heifers (no. = 9) plus ewe hoggets (no. = 27) were co-grazed (1: 1 M0·75) using continuous (C-CS) or rotational (R-CS) stocking. In experiment 2 (126 days), a cattle alone (no. = 9) treatment was included under each stocking system (C-C and R-C). Initial live weight of heifers was 266 (s.e. 4·5) and 232 (s.e. 4·4) kg and that of hoggets was 54 (s.e. 0·9) and 47 (s.e. 0·7) kg in experiments 1 and 2, respectively. In both experiments, the area offered daily to R-CS group was manipulated to promote a weekly live-weight change in sheep similar to that on the C-CS treatment. C-C cattle in experiment 2 were grazed at similar sward surface height (SSH) to C-CS, and R-C cattle at similar pre- and post-grazing SSH to R-CS. SSH was measured daily on all treatments and regulated on the continuously stocked treatments by addition and removal of non-experimental animals. Organic matter intake (OMI) was determined from the ratio of n-alkanes in faeces and herbage. Animals were weighed weekly.
Mean SSH on continuously stocked pastures was 5·10 (s.e. 0·03) and 4·26 (s.e. 0·02) cm for C-CS in experiments 1 and 2, respectively, and 4·27 (s.e. 0·02) cm for C-C in experiment 2. The mean pre- and post-grazing SSH for R-CS was 15·9 (s.e. 0·12) and 5·60 (s.e. 0·07) cm, respectively in experiment 1, and 15·2 (s.e. 0·08) and 4·82 (s.e. 0·03) cm, respectively in experiment 2. On R-C swards pre- and post-grazing SSH was 14·9 (s.e. 0·08) and 4·87 (s.e. 0·03) cm, respectively.
In experiment 1, cattle continuously co-grazed with sheep grew significantly more slowly than those rotationally co-grazed with sheep (804 (s.e. 41·6) v. 1039 (s.e. 47·7) g/day, P < 0·01). Sheep LWG did not differ between stocking treatments (150 v. 138 g, P > 0·05 for C-CS and R-CS respectively). These findings were confirmed in the second experiment in which C-CS cattle only grew at 0·69 of the daily LWG achieved by R-CS cattle (706 v. 1028, (s.e. 72) g/day; P < 0·05) at similar sheep LWG (155 v. 147, (s.e. 6·5) g/day respectively). LWG of C-C and R-C cattle was similar (916 v. 1022, (s.e. 72) g/day; P > 0·05). LWG per ha in both experiments was higher on R-CS than on C-CS treatments, and on cattle alone than on CS treatments. Treatment effects on OMI and final fasted live weight were similar in pattern to LWG.
It is suggested that the observed disadvantage to cattle when co-grazed with sheep under continuous stocking and the lack of effect when rotationally co-grazed reflected a difference in the two stocking systems in providing opportunities for complementary/competitive use of pasture resources.