Hypergastrinaemia, abomasal bacterial population densities and pH in sheep infected with Ostertagia circumcincta

Simcock, D.C., Joblin, K.N., Scott, I., Burgess, D.M., Rogers, C.W., Pomroy, W.E., and Simpson, H.V. (1999) Hypergastrinaemia, abomasal bacterial population densities and pH in sheep infected with Ostertagia circumcincta. International Journal for Parasitology, 29 (7). pp. 1053-1063.

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Abstract

Serum gastrin and pepsinogen concentrations, food intake, abomasal pH and abomasal aerotolerant and anaerobic bacterial populations were measured in sheep infected with Ostertagia circumcincta to search for links between hypergastrinaemia, food intake and changes in the abomasal environment. Abomasal pH and serum gastrin and pepsinogen concentrations were elevated in each of five sheep infected via abomasal cannulae with 150 000 exsheathed larval stage three, followed 11 days later by 100 000 sheathed larvae given intraruminally. Unparasitised abomasa contained aerotolerant bacterial population densities of between 103 and 106 cells ml−1 and these did not change significantly following parasitism. In contrast, anaerobic bacterial population densities increased markedly by about 104-fold following parasitism. Anaerobic numbers changed rapidly when abomasal pH increased from 2.5 to 3.5. At pH 4 and above, anaerobic bacterial numbers approached levels expected in rumen contents but parameters other than pH did not relate to bacterial numbers. Brief periods when serum gastrin was lower than expected, coinciding with raised abomasal pH, were not explicable by increased bacterial numbers. Food intake, which decreased for a variable period from around Day 5 p.i., correlated poorly with serum gastrin concentration, suggesting hypergastrinaemia is not the sole cause of anorexia in parasitised animals. The survival of substantial numbers of rumen bacteria in the abomasum at only slightly raised pH may significantly lower the bacterial protein available to the sheep.

Item ID: 36388
Item Type: Article (Research - C1)
ISSN: 1879-0135
Keywords: abomasal ph; abomasal microbes; anaerobic bacteria; appetite; Ostertagia circumcincta; serum gastrin; sheep
Funders: C. Alma Baker Trust, E. & C. Thoms Bequest
Date Deposited: 24 Sep 2015 23:14
FoR Codes: 07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070707 Veterinary Microbiology (excl Virology) @ 50%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0707 Veterinary Sciences > 070708 Veterinary Parasitology @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970107 Expanding Knowledge in the Agricultural and Veterinary Sciences @ 100%
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