Ontogenesis of peptide transport and morphological changes in the ovine gastrointestinal tract

Abstract

Nutrient absorption is important in all stages of life. As the diet of an animal changes from birth on, morphological and biochemical adaptation can be anticipated in order to accommodate changing demands. The main focus of the present study was to examine the relationship between age and diet on the potential for peptide transport via PepT1 in the gastrointestinal tract of lambs and to relate changes of peptide transport capability to morphological changes. A 2x4 factorial arrangement of treatments was used with 32 crossbred lambs. Four blocks were created based upon gender, birth type (single or twin), birth weight, and birth date. Lambs were randomly allotted at birth to receive or not to receive a creep diet. All lambs were allowed to nurse. Sampling times of 2, 4, 6, or 8 wk were randomly allotted to lambs. Samples for RNA extraction and histological evaluation were taken from the dorsal rumen, ventral rumen, omasum, duodenum, jejunum, and ileum. Villi were about 7% shorter (P < 0.09) in lambs receiving creep feed. Papillary height and width increased linearly (P < 0.001 and P < 0.0001, respectively) with age. Total and keratinized epithelial cells in the stomach decreased (P < 0.03 and P < 0.004, respectively) with age and were fewer (P < 0.0002 and P < 0.0001, respectively) in lambs receiving creep feed. Creep feeding appears to have slightly altered the mucosal structure of the small intestine and it was advantageous in that it iii stimulated papillary growth and thus predisposed the rumen for the introduction of feed into the diet. A 2.8 kb oPepT1 mRNA was present in all tissues studied by 2 wk, and age did not significantly influence the abundance of oPepT1 mRNA in the small intestine or stomach. In the small intestine, abundance of oPepT1 mRNA was greatest (P < 0.0007) in the jejunum. In the stomach, abundance of oPepT1 mRNA was greatest (P < 0.01) in the dorsal rumen. In the stomach, particularly in the rumen, a greater abundance of oPepT1 mRNA was observed in lambs not receiving the creep diet. It seems likely that a stimulus for development is coming from the non-luminal direction, possibly bloodborne, and may be involved in the ontogenesis of oPepT1. Peptide transport appears to be a physiologically important process in the young lamb and the rumen appears to be involved in the transport of peptides, particularly in nursing lambs.

Morphological and HistochemicalStudy of Small Intestine InIndigenousDucks (Anasplayrhynchos)

“…The crypts depth was correlated with the intestinal cells turnover rate and the increase in crypts depth indicates the need for enterocyte replacement and higher tissue turnover [31]. The crypt depth may be an important factor that determines the ability of the crypts to sustain the increase in the villus height as well as to maintain the villus structure [32].The ratio of villus 30.09 ± 1.90 The different letters in one raw denoted that there were significant differences between male and female indigenous ducks, in all traits at p≤0.01.…”

BOARD-INVITED REVIEW: Peptide absorption and utilization: Implications for animal nutrition and health

“…The developmental regulation of ovine PepT1 in the dorsal rumen, ventral rumen, omasum, duodenum, jejunum, and ileum of lambs was studied at 2, 4, 6, and 8 wk of age (Poole et al, 2003). Ovine PepT1 was present in all tissues examined at 2 wk of age and was not influenced by age.…”

Colostro bovino liofilizado como substituto do colostro caprino e o desenvolvimento do epitélio intestinal de cabritos durante o período de aquisição de proteção passiva

“…Os valores para a atividade das peptidases e dissacaridases no duodeno são apresentados na Tabela No jejuno, vilosidades altas e digitiformes foram observadas, o que esta de acordo com a literatura (BESSI et al, 2002a;BESSI et al, 2002b;KINDLEIN et al;2008b;POOLE et al, 2003). Vilosidades em forma de folha, tais como as observados neste estudo, também foram detectadas por Kindlein et al (2008b) em bezerros com três dias de idade.…”

“…A maior altura das vilosidades presentes no jejuno está relacionada com aumento da área superficial e, conseqüentemente, com maior condição de absorção neste segmento do intestino delgado. Nos ruminantes recém-nascidos, a maior área superficial possui importância significativa, uma vez que, a absorção de imunoglobulinas nas primeiras horas de vida ocorre principalmente neste segmento (BESSI et al, 2002a;BESSI et al, 2002b;POOLE et al 2003).…”