Developmental changes in morphometry of the small intestine and jejunal sucrase activity during the first nine weeks of postnatal growth in pigs1

Abstract

The objective of this study was to investigate the development of small intestinal size and digestive capacity of the jejunum in growing pigs. The weight, length, surface area, and mucosa weight of the small intestine were measured when pigs were 1, 3, 5, and 9 wk of age. Sucrase and alkaline phosphatase (ALP) activities of the jejunal brush-border membrane, prepared by differential centrifugation and Mg2+ precipitation, were determined at the respective postnatal stages. Body weights increased 7-fold from 2.7 kg at 1 wk to 23.32 kg at 9 wk postnatal. Body weight gains were greater (P < 0.05) from wk 3 to 5 than from wk 1 to 3. Weights of the small intestine and of the intestinal mucosa increased faster (P < 0.05) from 3 to 5 wk than from 1 to 3 wk; the slowest increase occurred from 5 to 9 wk. Weights of the duodenum, jejunum, and ileum, and mucosa from the respective sections increased (P < 0.05) as pigs grew from 3 to 9 wk. Mucosa weight relative to the weight of the section was greater (P < 0.05) for the duodenum and jejunum than for the ileum at 9 wk of age. Between the ages of 3 and 9 wk, the increase in mucosa weight was highest for the jejunum followed by the duodenum and the ileum. The increase was greatest for the duodenum followed by the jejunum and the ileum when mucosal weight was expressed per unit of appropriate intestinal section weight. There was a 55-fold increase in jejunal sucrase activity from 1 to 9 wk; the greatest rate of increase occurred between 5 and 9 wk. Total jejunal ALP activities in pigs at 9 wk was greater (P < 0.05) than at 5 wk, which in turn was greater than at 1 wk of age. In summary, increases in BW during the first 9 wk of postnatal growth in pigs are accompanied by significant developmental changes in digestive capacity including intestinal weights, length, and area as well as jejunal brush-border sucrase and ALP activities.

Developmental changes of jejunal brush-border enzyme activity in growing Jinhua gilts

“…The Jinhua gilt's intestinal weight and length increased in direct proportion to its body weight. The results are in accordance with previous reports (Aodeola and King, 2006). Jensen et al (1997) also reported that the weight of the small intestine and the length of the small intestine were described as a function of the body weight.…”

“…The result indicated that, from 35 to 125 days of age, the small intestine of Jinhua gilts undergoes a substantial increase in physical size to accommodate the processing of ingested nutrients. This result is similar to that reported by Adeola and King (2006), who observed that body weight, the weight and length of small intestine, as well as mucosa weight increase with age from 1 to 9 weeks. However, at the same age, Jinhua gilts have a lower weight and length of the small intestine compared with the breed previously reported (Jensen et al, 1997;Aodeola and King, 2006), which suggests that these differences may be attributed to the growth performance of different breeds.…”

“…In the current study, the duodenum, jejunum, and ileum represented 11, 8, and 7%, and 77, 83, and 85%, and 12, 9, and 8%, respectively, of length of the small intestine in 35-, 80-, and 125-day-old Jinhua gilts. The results indicate that the jejunum represents more of the length of small intestine as the pig grows (Adeola and King, 2006).…”

“…It has been reported that the duodenum, jejunum, and ileum represent 4 to 5%, 88 to 91%, and 4 to 5%, respectively, of the length of the small intestine in fully-grown pigs (Yen, 2001). Adeola and King (2006) also reported that the duodenum accounts for approximately 10, 9 and 7% of the length of the small intestine in 3-, 5-and 9-week-old pigs, respectively. Corresponding numbers for the jejunum are approximately 78, 81, and 84 % with values of 12, 10, and 9% for the ileum.…”

“…The growth of an animal depends in part on its capacity to digest and assimilate ingested macromolecules, and any impairment of this is expected to constrain growth (Adeola and King, 2006). Intestinal digestion is mainly carried out by enzymes bound to the microvillus membrane of absorptive cells.…”